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.

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...

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

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

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...

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.

Qualitative and quantitative assessment of Illumina's forensic STR and SNP kits on MiSeq FGx™.

PubMed

Sharma, Vishakha; Chow, Hoi Yan; Siegel, Donald; Wurmbach, Elisa

2017-01-01

Massively parallel sequencing (MPS) is a powerful tool transforming DNA analysis in multiple fields ranging from medicine, to environmental science, to evolutionary biology. In forensic applications, MPS offers the ability to significantly increase the discriminatory power of human identification as well as aid in mixture deconvolution. However, before the benefits of any new technology can be employed, a thorough evaluation of its quality, consistency, sensitivity, and specificity must be rigorously evaluated in order to gain a detailed understanding of the technique including sources of error, error rates, and other restrictions/limitations. This extensive study assessed the performance of Illumina's MiSeq FGx MPS system and ForenSeq™ kit in nine experimental runs including 314 reaction samples. In-depth data analysis evaluated the consequences of different assay conditions on test results. Variables included: sample numbers per run, targets per run, DNA input per sample, and replications. Results are presented as heat maps revealing patterns for each locus. Data analysis focused on read numbers (allele coverage), drop-outs, drop-ins, and sequence analysis. The study revealed that loci with high read numbers performed better and resulted in fewer drop-outs and well balanced heterozygous alleles. Several loci were prone to drop-outs which led to falsely typed homozygotes and therefore to genotype errors. Sequence analysis of allele drop-in typically revealed a single nucleotide change (deletion, insertion, or substitution). Analyses of sequences, no template controls, and spurious alleles suggest no contamination during library preparation, pooling, and sequencing, but indicate that sequencing or PCR errors may have occurred due to DNA polymerase infidelities. Finally, we found utilizing Illumina's FGx System at recommended conditions does not guarantee 100% outcomes for all samples tested, including the positive control, and required manual editing due to low read numbers and/or allele drop-in. These findings are important for progressing towards implementation of MPS in forensic DNA testing.

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...

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.

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

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.

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.

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...

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 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.

A Boilerplate Capsule Test Technique for the Orion Parachute Test Program

NASA Technical Reports Server (NTRS)

Moore, James W.; Fraire, Usbaldo, Jr.

2013-01-01

The test program developing parachutes for the Orion/MPCV includes drop tests of a Parachute Test Vehicle designed to emulate the wake of the Orion capsule. Delivery of this test vehicle to the initial velocity, altitude, and orientation required for the test is a difficult problem involving multiple engineering disciplines. The available delivery of aircraft options imposed constraints on the test vehicle development and concept of operations. This paper describes the development of this test technique. The engineering challenges include the extraction from an aircraft and separation of two aerodynamically unstable vehicles, one of which will be delivered to a specific orientation with reasonably small rates. The desired attitude is achieved by precisely targeting the separation point using on-board monitoring of the motion. The design of the test vehicle is described. The trajectory simulations and other analyses used to develop this technique and predict the behavior of the test article are reviewed in detail. The application of the technique on several successful drop tests is summarized.

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.

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.

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.

Blast Mitigation Seat Analysis - Assessment of the Effect of Personal Protective Equipment on the 5th Percentile Female Anthropomorphic Test Devices Performance in Drop Tower Evaluations (Briefing Charts)

DTIC Science & Technology

2015-08-01

for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data ...sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden...UNCLASSIFIED UNCLASSIFIED • Baseline drop tower data collected from Anthropomorphic Test Devices (ATDs) seated in 12 models of Commercial Off-The-Shelf

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...

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

Refuelling the future: Progress towards testing drop-in biofuels in replacing conventional fuel for commercial flights

NASA Astrophysics Data System (ADS)

Noh, H. Mohd; Mahamad Taher, M. N.; Rodrigo, G. A.; Rahman, N. A. Abdul; Ismail, S.; Mat Rani, M.; Salleh, I. Mohd; Dahdi, Y.; Wan, W. N. S.; Razak, Abdul; Mat Ghani, M. S.; Yusoff, M. R.; Benito, A.

2018-05-01

Due to different motivations, including the interest in reducing the dependency on fossil fuel and environmental implications, drop-in biofuels are a reality in today’s commercial aviation. This paper summarizes the state-of-the-art of biomass-origin kerosene certification and provides references to the commercial flights performed so far by all airlines around the world. Results prove that the normal operation of the flights using the drop-in biofuel do not experience any repercussion in the performance in both engine and maintenance.

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 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.

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.

Current Trends on the Applicability of Ground Aerospace Materials Test Data to Space System Environments

NASA Technical Reports Server (NTRS)

Hirsch, David B.

2010-01-01

This slide presentation discusses the application of testing aerospace materials to the environment of space for flammability. Test environments include use of drop towers, and the parabolic flight to simulate the low gravity environment of space.

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.

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.

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.

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.

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.

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.

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.

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

Instrumentation and telemetry systems for free-flight drop model testing

NASA Technical Reports Server (NTRS)

Hyde, Charles R.; Massie, Jeffrey J.

1993-01-01

This paper presents instrumentation and telemetry system techniques used in free-flight research drop model testing at the NASA Langley Research Center. The free-flight drop model test technique is used to conduct flight dynamics research of high performance aircraft using dynamically scaled models. The free-flight drop model flight testing supplements research using computer analysis and wind tunnel testing. The drop models are scaled to approximately 20 percent of the size of the actual aircraft. This paper presents an introduction to the Free-Flight Drop Model Program which is followed by a description of the current instrumentation and telemetry systems used at the NASA Langley Research Center, Plum Tree Test Site. The paper describes three telemetry downlinks used to acquire the data, video, and radar tracking information from the model. Also described are two telemetry uplinks, one used to fly the model employing a ground-based flight control computer and a second to activate commands for visual tracking and parachute recovery of the model. The paper concludes with a discussion of free-flight drop model instrumentation and telemetry system development currently in progress for future drop model projects at the NASA Langley Research Center.

NASA Glenn Icing Research Tunnel: 2014 and 2015 Cloud Calibration Procedures and Results

NASA Technical Reports Server (NTRS)

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

2015-01-01

This report summarizes the current status of the NASA Glenn Research Center (GRC) Icing Research Tunnel cloud calibration: specifically, the cloud uniformity, liquid water content, and drop-size calibration results from both the January-February 2014 full cloud calibration and the January 2015 interim cloud calibration. Some aspects of the cloud have remained the same as what was reported for the 2014 full calibration, including the cloud uniformity from the Standard nozzles, the drop-size equations for Standard and Mod1 nozzles, and the liquid water content for large-drop conditions. Overall, the tests performed in January 2015 showed good repeatability to 2014, but there is new information to report as well. There have been minor updates to the Mod1 cloud uniformity on the north side of the test section. Also, successful testing with the OAP-230Y has allowed the IRT to re-expand its operating envelopes for large-drop conditions to a maximum median volumetric diameter of 270 microns. Lastly, improvements to the collection-efficiency correction for the SEA multi-wire have resulted in new calibration equations for Standard- and Mod1-nozzle liquid water content.

Drop finger caused by 8th cervical nerve root impairment: a clinical case series.

PubMed

Koda, Masao; Furuya, Takeo; Rokkaku, Tomoyuki; Murakami, Masazumi; Ijima, Yasushi; Saito, Junya; Kitamura, Mitsuhiro; Ohtori, Seiji; Orita, Sumihisa; Inage, Kazuhide; Yamazaki, Masashi; Mannoji, Chikato

2017-04-01

Recently, it has been reported that impairment by an 8th cervical nerve root lesion can cause drop finger, namely C8 drop finger. Here, we report a clinical case series of C8 drop finger to reveal the clinical outcome of surgical treatments to allow for a better choice of treatment. The present study included 17 consecutive patients who were diagnosed as having C8 drop finger, in which muscle strength of the extensor digitorum communis (EDC) showed a manual muscle testing (MMT) grade of 3 or less. We retrospectively investigated the clinical characteristics of C8 drop finger and recovery of muscle power was measured by subtraction of preoperative MMT of the EDC from the final follow-up values. Nine cases showed recovery of muscle power of EDC, whereas the remaining eight cases did not show any recovery including two cases of deterioration. None of the conservatively treated patients showed any recovery. Surgically treated cases included two cases of deterioration. In the cases showing recovery, recovery began 9.9 months after surgery on average and recovery took 13.8 months after surgery on average. There was a significant difference in the recovery of MMT grade between the groups treated conservatively and surgically (p = 0.049). Preoperative MMT grade of EDC showed a moderate correlation with postoperative recovery (r 2  = 0.45, p = 0.003). In other words, the severity of preoperative muscular weakness correlated negatively with postoperative recovery. C8 drop finger is better treated by surgery than conservative therapy.

Puddle Jumping

NASA Astrophysics Data System (ADS)

Wollman, Andrew; Snyder, Trevor; Weislogel, Mark

2014-11-01

Rebounding droplets from superhydrophobic surfaces have attracted significant public and scientific attention because they are both enjoyable as well as industrially relevant. Demonstrations of bouncing droplets with volumes between 0.003 and 0.03 ml are common in the literature and limited primarily by gravity. In this presentation we demonstrate large droplet ``rebounds'' made possible by low-gravity testing in a drop tower. The up to 300 ml drops are best described as puddles that launch in a nearly identical manner to rebounding drops 4 orders of magnitude smaller in volume. A variety of jumping liquid and gas puddles are shown including puddles of highly specified and unusual initial geometry. The large length sales of the capillary fluidic surfaces ~ O (10 cm) enable 3D printing of all superhydrophobic surface topologies demonstrated. In addition, we demonstrate such puddle jumping as a passive drop-on-demand technique for large low-gravity drop dynamics investigations; such as collisions, rebounds, heat and mass transfer, and containerless possessing.

Technical activities report: Heat, water, and mechanical studies

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

Alexander, W.K.

1951-10-04

Topics in the heat studies section include: front and rear face reflector shields at the C-pile; process tube channel thermocouples; water temperature limits for horizontal rods; slug temperature and thermal conductivity calculations; maximum slug-end cap temperature; boiling consideration studies; scram time limit for Panellit alarm; heat transfer test; slug stresses; thermal insulation of bottom tube row at C-pile; flow tests; present pile enrichment; electric analog; and measurement of thermal contact resistance. Topics in the water studies section include: 100-D flow laboratory; process water studies; fundamental studies on film formation; coatings on tip-offs; can difference tests; slug jacket abrasion at highmore » flow rates; corrosion studies; front tube dummy slugs; metallographic examination of tubes from H-pile; fifty-tube mock-up; induction heating facility; operational procedures and standards; vertical safety rod dropping time tests; recirculation; and power recovery. Mechanical development studies include: effect of Sphincter seal and lubricant VSR drop time; slug damage; slug bubble tester; P-13 removal; chemical slug stripper; effect of process tube rib spacing and width; ink facility installation; charging and discharging machines; process tube creep; flapper nozzle assembly test; test of single gun barrel assembly; pigtail fixture test; horizontal rod gland seal test; function test of C-pile; and intermediate test of Ball 3-X and VSR systems.« less

Virtual prototyping of drop test using explicit analysis

NASA Astrophysics Data System (ADS)

Todorov, Georgi; Kamberov, Konstantin

2017-12-01

Increased requirements for reliability and safety, included in contemporary standards and norms, has high impact over new product development. New numerical techniques based on virtual prototyping technology, facilitates imrpoving product development cycle, resutling in reduced time/money spent for this stage as well as increased knowledge about certain failure mechanism. So called "drop test" became nearly a "must" step in development of any human operated product. This study aims to demonstrate dynamic behaviour assessment of a structure under impact loads, based on virtual prototyping using a typical nonlinear analysis - explicit dynamics. An example is presneted, based on a plastic container that is used as cartridge for a dispenser machine exposed to various work conditions. Different drop orientations were analyzed and critical load cases and design weaknesses have been found. Several design modifications have been proposed, based on detailed analyses results review.

Short Duration Reduced Gravity Drop Tower Design and Development

NASA Astrophysics Data System (ADS)

Osborne, B.; Welch, C.

The industrial and commercial development of space-related activities is intimately linked to the ability to conduct reduced gravity research. Reduced gravity experimentation is important to many diverse fields of research in the understanding of fundamental and applied aspects of physical phenomena. Both terrestrial and extra-terrestrial experimental facilities are currently available to allow researchers access to reduced gravity environments. This paper discusses two drop tower designs, a 2.0 second facility built in Australia and a proposed 2.2 second facility in the United Kingdom. Both drop towers utilise a drag shield for isolating the falling experiment from the drag forces of the air during the test. The design and development of The University of Queensland's (Australia) 2.0 second drop tower, including its specifications and operational procedures is discussed first. Sensitive aspects of the design process are examined. Future plans are then presented for a new short duration (2.2 sec) ground-based reduced gravity drop tower. The new drop tower has been designed for Kingston University (United Kingdom) to support teaching and research in the field of reduced gravity physics. The design has been informed by the previous UQ drop tower design process and utilises a catapult mechanism to increase test time and also incorporates features to allow participants for a variety of backgrounds (from high school students through to university researchers) to learn and experiment in reduced gravity. Operational performance expectations for this new facility are also discussed.

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

30 CFR 250.527 - What must I include in my casing pressure request?

Code of Federal Regulations, 2010 CFR

2010-07-01

... and the calculated daily production rate during last well test (oil, gas, basic sediment, and water... (dry tree, hybrid, or subsea); (n) Date of diagnostic test; (o) Well schematic; (p) Water depth; (q...: (1) Bleed down/buildup test; (2) Shut-in the well and monitor the pressure drop test; (3) Constant...

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.

The effect of dropping height on jumping performance in trained and untrained prepubertal boys and girls.

PubMed

Bassa, Eleni I; Patikas, Dimitrios A; Panagiotidou, Aikaterini I; Papadopoulou, Sophia D; Pylianidis, Theofilos C; Kotzamanidis, Christos M

2012-08-01

Plyometric training in children, including different types of jumps, has become common practice during the last few years in different sports, although there is limited information about the adaptability of children with respect to different loads and the differences in performance between various jump types. The purpose of this study was to examine the effect of gender and training background on the optimal drop jump height of 9- to 11-year-old children. Sixty prepubertal (untrained and track and field athletes, boys and girls, equally distributed in each group [n = 15]), performed the following in random order: 3 squat jumps, 3 countermovement jumps (CMJs) and 3 drop jumps from heights of 10, 20, 30, 40, and 50 cm. The trial with the best performance in jump height of each test was used for further analysis. The jump type significantly affected the jump height. The jump height during the CMJ was the highest among all other jump types, resulting in advanced performance for both trained and untrained prepubertal boys and girls. However, increasing the dropping height did not change the jumping height or contact time during the drop jump. This possibly indicates an inability of prepubertal children to use their stored elastic energy to increase jumping height during drop jumps, irrespective of their gender or training status. This indicates that children, independent of gender and training status, have no performance gain during drop jumps from heights up to 50 cm, and therefore, it is recommended that only low drop jump heights be included in plyometric training to limit the probability of sustaining injuries.

Experimental Study of Grit Particle Enhancement in Non-Shock Ignition

NASA Astrophysics Data System (ADS)

Browning, Richard V.; Peterson, Paul D.; Roemer, Edward L.; Oldenborg, Michael R.; Thompson, Darla G.; Deluca, Racci

2006-07-01

The drop weight impact test is the most commonly used configuration for evaluating sensitivity of explosives to non-shock ignition. Although developed 60 years ago and widely used both as a material compression test and as a test bed for understanding the ignition process itself, little is known about the flow mechanisms or involvement of grit particles as sensitizing agents. In this paper, we present the results of a series of experiments designed to study the flow mechanisms and events leading up to ignition. The experimental configuration used involves two pellet sizes, 3 and 5 mm in diameter, tested with three conditions: (1) smooth steel anvils, (2) standard flint sandpaper, and (3) shed grit particles loaded between the steel anvils and the pellet faces. Diagnostics include optical micrographs, and scanning electron micrographs. Un-reacted samples show a variety of morphologies, including what appear to be quenched reaction sites, even at very low drop heights. Quasi-static crushing experiments were also done to quantify load-time histories.

Experimental Study of Grit Particle Enhancement in Non-Shock Ignition of PBX 9501

NASA Astrophysics Data System (ADS)

Peterson, Paul

2005-07-01

The drop weight impact test is the most commonly used configuration for evaluating sensitivity of explosives to non-shock ignition. Although developed 60 years ago and widely used both as a material compression test and as a test bed for understanding the ignition process itself, little is known about the flow mechanisms or involvement of grit particles as sensitizing agents. In this paper we present the results of a series of experiments designed to study the flow mechanisms and events leading up to ignition. The experimental configuration used involves two pellet sizes, 3 and 5 mm in diameter, tested in three conditions, (1) with smooth steel anvils, (2) with standard flint sandpaper, and (3) with shed grit particles loaded between the steel anvils and the pellet faces. Diagnostics include optical micrographs, and scanning electron micrographs. Un-reacted samples show a variety of morphologies, including what appear to be quenched reaction sites, even at very low drop heights. Quasi-static crushing experiments were also done to quantify load-time histories.

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.

Blood drop size in passive dripping from weapons.

PubMed

Kabaliuk, N; Jermy, M C; Morison, K; Stotesbury, T; Taylor, M C; Williams, E

2013-05-10

Passive dripping, the slow dripping of blood under gravity, is responsible for some bloodstains found at crime scenes, particularly drip trails left by a person moving through the scene. Previous work by other authors has established relationships, under ideal conditions, between the size of the stain, the number of spines and satellite stains, the roughness of the surface, the size of the blood droplet and the height from which it falls. To apply these relationships to infer the height of fall requires independent knowledge of the size of the droplet. This work aims to measure the size of droplets falling from objects representative of hand-held weapons. Pig blood was used, with density, surface tension and viscosity controlled to fall within the normal range for human blood. Distilled water was also tested as a reference. Drips were formed from stainless steel objects with different roughnesses including cylinders of diameter between 10 and 100 mm, and flat plates. Small radius objects including a knife and a wrench were also tested. High speed images of the falling drops were captured. The primary blood drop size ranged from 4.15±0.11 mm up to 6.15±0.15 mm (depending on the object), with the smaller values from sharper objects. The primary drop size correlated only weakly with surface roughness, over the roughness range studied. The number of accompanying droplets increased with the object size, but no significant correlation with surface texture was observed. Dripping of blood produced slightly smaller drops, with more accompanying droplets, than dripping water. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

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.

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.

Design and testing of an energy-absorbing crewseat for the F/FB-111 aircraft. Volume 3: Data from crew module testing

NASA Technical Reports Server (NTRS)

Shane, S. J.

1985-01-01

Over the past years, several papers and reports have documented the unacceptably high injury rate during the escape sequence (including the ejection and ground impact) of the crew module for F/FB-111 aircraft. This report documents a program to determine if the injury potential could be reduced by replacing the existing crewseats with energy absorbing crewseats. 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 werre conducted. The vertical drop tests were used to obtain comparative data between the energy absorbing and operational seats.

Drop-out from a drug treatment clinic and associated reasons.

PubMed

Hoseinie, Leila; Gholami, Zhaleh; Shadloo, Behrang; Mokri, Azarakhsh; Amin-Esmaeili, Masoumeh; Rahimi-Movaghar, Afarin

2017-05-01

The aim of this study was to assess drop-out rates and associated reasons among patients at the Iranian National Center for Addiction Studies (INCAS) clinic. In a one-year period (April 2014 to March 2015), all patients with drug dependence who had been referred for treatment and attended for a first assessment were included in this study (N=242). Those who received treatment were followed until March 2016. Survival analysis showed that 70.2% had dropped out from treatment. Log rank test showed that treatment drop-out rates differed between the different approaches used (P < 0.001), with the lowest slope inbuprenorphine maintenance treatment and the highest in the detoxification programme. Drop-out rates within the first three months was 62% (SE= 0.05) and 82.4% (SE=0.03) for opioids and stimulants dependence, respectively. Analyses were performed using SPSS (Version 21.0) and STATA software, (version 13.0). From the patients' perspective, motivational inconsistencies were considered as the main reason for not starting or leaving treatment. The findings of this study could give service providers a better grasp of drop-out rates and the associated reasons.

An Airborne Parachute Compartment Test Bed for the Orion Parachute Test Program

NASA Technical Reports Server (NTRS)

Moore, James W.; Romero, Leah M.

2013-01-01

The test program developing parachutes for the Orion/MPCV includes drop tests with parachutes deployed from an Orion-like parachute compartment at a wide range of dynamic pressures. Aircraft and altitude constraints precluded the use of an Orion boilerplate capsule for several test points. Therefore, a dart-shaped test vehicle with a hi-fidelity mock-up of the Orion parachute compartment has been developed. The available aircraft options imposed constraints on the test vehicle development and concept of operations. Delivery of this test vehicle to the desired velocity, altitude, and orientation required for the test is a di cult problem involving multiple engineering disciplines. This paper describes the development of the test technique. The engineering challenges include extraction from an aircraft, reposition of the extraction parachute, and mid-air separation of two vehicles, neither of which has an active attitude control system. The desired separation behavior is achieved by precisely controlling the release point using on-board monitoring of the motion. The design of the test vehicle is also described. The trajectory simulations and other analyses used to develop this technique and predict the behavior of the test vehicle are reviewed in detail. The application of the technique on several successful drop tests is summarized.

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.

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.

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.

384 hanging drop arrays give excellent Z-factors and allow versatile formation of co-culture spheroids.

PubMed

Hsiao, Amy Y; Tung, Yi-Chung; Qu, Xianggui; Patel, Lalit R; Pienta, Kenneth J; Takayama, Shuichi

2012-05-01

We previously reported the development of a simple, user-friendly, and versatile 384 hanging drop array plate for 3D spheroid culture and the importance of utilizing 3D cellular models in anti-cancer drug sensitivity testing. The 384 hanging drop array plate allows for high-throughput capabilities and offers significant improvements over existing 3D spheroid culture methods. To allow for practical 3D cell-based high-throughput screening and enable broader use of the plate, we characterize the robustness of the 384 hanging drop array plate in terms of assay performance and demonstrate the versatility of the plate. We find that the 384 hanging drop array plate performance is robust in fluorescence- and colorimetric-based assays through Z-factor calculations. Finally, we demonstrate different plate capabilities and applications, including: spheroid transfer and retrieval for Janus spheroid formation, sequential addition of cells for concentric layer patterning of different cell types, and culture of a wide variety of cell types. Copyright © 2011 Wiley Periodicals, Inc.

384 Hanging Drop Arrays Give Excellent Z-factors and Allow Versatile Formation of Co-culture Spheroids

PubMed Central

Hsiao, Amy Y.; Tung, Yi-Chung; Qu, Xianggui; Patel, Lalit R.; Pienta, Kenneth J.; Takayama, Shuichi

2012-01-01

We previously reported the development of a simple, user-friendly, and versatile 384 hanging drop array plate for 3D spheroid culture and the importance of utilizing 3D cellular models in anti-cancer drug sensitivity testing. The 384 hanging drop array plate allows for high-throughput capabilities and offers significant improvements over existing 3D spheroid culture methods. To allow for practical 3D cell-based high-throughput screening and enable broader use of the plate, we characterize the robustness of the 384 hanging drop array plate in terms of assay performance and demonstrate the versatility of the plate. We find that the 384 hanging drop array plate performance is robust in fluorescence- and colorimetric-based assays through z-factor calculations. Finally, we demonstrate different plate capabilities and applications, including: spheroid transfer and retrieval for Janus spheroid formation, sequential addition of cells for concentric layer patterning of different cell types, and culture of a wide variety of cell types. PMID:22161651

Pressure Drop Across Woven Screens Under Uniform and Nonuniform Flow Conditions. [flow characteristics of water through Dutch twill and square weave fabrics

NASA Technical Reports Server (NTRS)

Ludewig, M.; Omori, S.; Rao, G. L.

1974-01-01

Tests were conducted to determine the experimental pressure drop and velocity data for water flowing through woven screens. The types of materials used are dutch twill and square weave fabrics. Pressure drop measures were made at four locations in a rectangular channel. The data are presented as change in pressure compared with the average entry velocity and the numerical relationship is determined by dividing the volumetric flow rate by the screen area open to flow. The equations of continuity and momentum are presented. A computer program listing an extension of a theoretical model and data from that computer program are included.

Orion Swing Drop 6

NASA Image and Video Library

2017-09-25

Water impact test of an 18,000-pound (8,165 kilogram) test version of the Orion spacecraft at NASA's Langley Research Center. NASA is swing drop testing this Orion capsule mock-up at Langley's Hydro Impact Basin to certify the actual Orion spacecraft for water landings. In a series of tests, Orion is being dropped in a variety of different conditions to help fine-tune NASA's predictions of Orion's landing loads.

Enhanced intelligent water drops algorithm for multi-depot vehicle routing problem

PubMed Central

Akutsah, Francis; Olusanya, Micheal O.; Adewumi, Aderemi O.

2018-01-01

The intelligent water drop algorithm is a swarm-based metaheuristic algorithm, inspired by the characteristics of water drops in the river and the environmental changes resulting from the action of the flowing river. Since its appearance as an alternative stochastic optimization method, the algorithm has found applications in solving a wide range of combinatorial and functional optimization problems. This paper presents an improved intelligent water drop algorithm for solving multi-depot vehicle routing problems. A simulated annealing algorithm was introduced into the proposed algorithm as a local search metaheuristic to prevent the intelligent water drop algorithm from getting trapped into local minima and also improve its solution quality. In addition, some of the potential problematic issues associated with using simulated annealing that include high computational runtime and exponential calculation of the probability of acceptance criteria, are investigated. The exponential calculation of the probability of acceptance criteria for the simulated annealing based techniques is computationally expensive. Therefore, in order to maximize the performance of the intelligent water drop algorithm using simulated annealing, a better way of calculating the probability of acceptance criteria is considered. The performance of the proposed hybrid algorithm is evaluated by using 33 standard test problems, with the results obtained compared with the solutions offered by four well-known techniques from the subject literature. Experimental results and statistical tests show that the new method possesses outstanding performance in terms of solution quality and runtime consumed. In addition, the proposed algorithm is suitable for solving large-scale problems. PMID:29554662

Enhanced intelligent water drops algorithm for multi-depot vehicle routing problem.

PubMed

Ezugwu, Absalom E; Akutsah, Francis; Olusanya, Micheal O; Adewumi, Aderemi O

2018-01-01

The intelligent water drop algorithm is a swarm-based metaheuristic algorithm, inspired by the characteristics of water drops in the river and the environmental changes resulting from the action of the flowing river. Since its appearance as an alternative stochastic optimization method, the algorithm has found applications in solving a wide range of combinatorial and functional optimization problems. This paper presents an improved intelligent water drop algorithm for solving multi-depot vehicle routing problems. A simulated annealing algorithm was introduced into the proposed algorithm as a local search metaheuristic to prevent the intelligent water drop algorithm from getting trapped into local minima and also improve its solution quality. In addition, some of the potential problematic issues associated with using simulated annealing that include high computational runtime and exponential calculation of the probability of acceptance criteria, are investigated. The exponential calculation of the probability of acceptance criteria for the simulated annealing based techniques is computationally expensive. Therefore, in order to maximize the performance of the intelligent water drop algorithm using simulated annealing, a better way of calculating the probability of acceptance criteria is considered. The performance of the proposed hybrid algorithm is evaluated by using 33 standard test problems, with the results obtained compared with the solutions offered by four well-known techniques from the subject literature. Experimental results and statistical tests show that the new method possesses outstanding performance in terms of solution quality and runtime consumed. In addition, the proposed algorithm is suitable for solving large-scale problems.

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

NASA Technical Reports Server (NTRS)

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

1989-01-01

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

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...

Preliminary drop-tower experiments on liquid-interface geometry in partially filled containers at zero gravity

NASA Technical Reports Server (NTRS)

Smedley, G.

1990-01-01

Plexiglass containers with rounded trapezoidal cross sections were designed and built to test the validity of Concus and Finn's existence theorem (1974, 1983) for a bounded free liquid surface at zero gravity. Experiments were carried out at the NASA Lewis two-second drop tower. Dyed ethanol-water solutions and three immiscible liquid pairs, with one liquid dyed, were tested. High-speed movies were used to record the liquid motion. Liquid rose to the top of the smaller end of the containers when the contact angle was small enough, in agreement with the theory. Liquid interface motion demonstrated a strong dependence on physical properties, including surface roughness and contamination.

Comparison of stretch reflex responses evoked during drop jumping in highly skilled atheles versus untrained subjects.

PubMed

Judge, L W; Burke, J R

2015-06-01

The purpose of the study was to describe changes in the excitability of the stretch reflex response (SRR) during different drop jumps as a function of training background and as an adaptation to a preseason sport-specific resistance training program. Twelve collegiate field event athletes (discus, hammer, javelin, shot put, and weight; 9 males and 3 females) and 12 college-aged control subjects performed the following three jumps: (1) countermovement jump (CMJ); (2) countermovement drop jump; and (3) bounce-drop jump (BDJ). Neuromechanical changes in the performance of drop jumps by athletes were measured during the sport-specific resistance training program. Pre-post testing of drop jump performance by control subjects was included for comparison. For each jump trial, ground reaction forces (GRF), electromyograms (EMG) and cinematographic data were collected. There were no training adaptations. However, jump heights were greater for the athletes than the controls among the different jumps with the jump heights for all subjects being less during the BDJ than CMJ and CDJ. In athletes only, there was a differential modulation of the SRR from the gastrocnemius muscle with different levels of background muscle activity for the CDJ and BDJ. There were changes in excitability of SRR from the gastrocnemius muscle as a function of training background. Interrelated neuromechanical mechanisms to include landing biomechanics, intrinsic musculotendinous tissue properties of the ankle, and centrally regulated motor commands may underlie the facilitation of the SRR from the gastrocnemius muscle in athletes as compared to controls.

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.

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

Fuel thermal stability effects on spray characteristics

NASA Technical Reports Server (NTRS)

Lefebvre, A. H.; Nickolaus, D.

1987-01-01

The propensity of a heated hydrocarbon fuel toward solids deposition within a fuel injector is investigated experimentally. Fuel is arranged to flow through the injector at constant temperature, pressure, and flow rate and the pressure drop across the nozzle is monitored to provide an indication of the amount of deposition. After deposits have formed, the nozzle is removed from the test rig and its spray performance is compared with its performance before deposition. The spray characteristics measured include mean drop size, drop-size distribution, and radial and circumferential fuel distribution. It is found that small amounts of deposition can produce severe distortion of the fuel spray pattern. More extensive deposition restores spray uniformity, but the nozzle flow rate is seriously curtailed.

A computer-controlled apparatus for micrometric drop deposition at liquid surfaces

NASA Astrophysics Data System (ADS)

Peña-Polo, Franklin; Trujillo, Leonardo; Sigalotti, Leonardo Di G.

2010-05-01

A low-cost, automated apparatus has been used to perform micrometric deposition of small pendant drops onto a quiet liquid surface. The approach of the drop to the surface is obtained by means of discrete, micron-scale translations in order to achieve deposition at adiabatically zero velocity. This process is not only widely used in scientific investigations in fluid mechanics and thermal sciences but also in engineering and biomedical applications. The apparatus has been designed to produce accurate deposition onto the surface and minimize the vibrations induced in the drop by the movement of the capillary tip. Calibration tests of the apparatus have shown that a descent of the drop by discrete translational steps of ˜5.6 μm and duration of 150-200 ms is sufficient to minimize its penetration depth into the liquid when it touches the surface layer and reduce to a level of noise the vibrations transmitted to it by the translation of the dispenser. Different settings of the experimental setup can be easily implemented for use in a variety of other applications, including deposition onto solid surfaces, surface tension measurements of pendant drops, and wire bonding in microelectronics.

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

Feasibility of granular bed filtration of an aerosol of ultrafine metallic particles including a pressure drop regeneration system.

PubMed

Bémer, D; Wingert, L; Morele, Y; Subra, I

2015-09-01

A process for filtering an aerosol of ultrafine metallic particles (UFP) has been designed and tested, based on the principle of a multistage granular bed. The filtration system comprised a succession of granular beds of varying thickness composed of glass beads of different diameters. This system allows the pressure drop to be regenerated during filtration ("on-line" mode) using a vibrating probe. Tests monitoring the pressure drop were conducted on a "10-L/min" low airflow rate device and on a "100-m(3)/hr" prototype. Granular bed unclogging is automated on the latter. The cyclic operation and filtration performances are similar to that of filter medium-based industrial dust collectors. Filtration of ultrafine metallic particles generated by different industrial processes such as arc welding, metal cutting, or spraying constitutes a difficult problem due to the high filter clogging properties of these particles and to the high temperatures generally encountered. Granular beds represent an advantageous means of filtering these aerosols with difficult properties.

Proceedings of the Second International Colloquium on Drops and Bubbles

NASA Technical Reports Server (NTRS)

Lecroissette, D. H. (Editor)

1982-01-01

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

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.

Evaluating Material Flammability in Microgravity and Martian Gravity Compared to the NASA Standard Normal Gravity Test

NASA Technical Reports Server (NTRS)

Oslon, Sandra. L.; Ferkul, Paul

2012-01-01

Drop tower tests are conducted at Martian gravity to determine the flammability of three materials compared to previous tests in other normal gravity and reduced gravity environments. The comparison is made with consideration of a modified NASA standard test protocol. Material flammability limits in the different gravity and flow environments are tabulated to determine the factor of safety associated with normal gravity flammability screening. Previous testing at microgravity and Lunar gravity indicated that some materials burned to lower oxygen concentrations in low gravity than in normal gravity, although the low g extinction limit criteria are not the same as 1g due to time constraints in drop testing. Similarly, the data presented in this paper for Martian gravity suggest that there is a gravity level below Earth s at which materials burn more readily than on Earth. If proven for more materials, this may indicate the need to include a factor of safety on 1g flammability limits.

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

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.

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...

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.

The Effect of a Combined High-Intensity Plyometric and Speed Training Program on the Running and Jumping Ability of Male Handball Players

PubMed Central

Cherif, Monsef; Said, Mohamed; Chaatani, Sana; Nejlaoui, Olfa; Gomri, Daghbaji; Abdallah, Aouidet

2012-01-01

Purpose The aim of this study was to investigate the effect of a combined program including sprint repetitions and drop jump training in the same session on male handball players. Methods Twenty-two male handball players aged more than 20 years were assigned into 2 groups: experimental group (n=11) and control group (n=11). Selection was based on variables “axis” and “lines”, goalkeepers were not included. The experimental group was subjected to 2 testing periods (test and retest) separated by 12 weeks of an additional combined plyometric and running speed training program. The control group performed the usual handball training. The testing period comprised, at the first day, a medical checking, anthropometric measurements and an incremental exercise test called yo-yo intermittent recovery test. 2 days later, participants performed the Repeated Sprint Ability test (RSA), and performed the Jumping Performance using 3 different events: Squat jump (SJ), Countermovement jump without (CMJ) and with arms (CMJA), and Drop jump (DJ). At the end of the training period, participants performed again the repeated sprint ability test, and the jumping performance. Results The conventional combined program improved the explosive force ability of handball players in CMJ (P=0.01), CMJA (P=0.01) and DJR (P=0.03). The change was 2.78, 2.42 and 2.62% respectively. No significant changes were noted in performances of the experimental group at the squat jump test and the drop jump with the left leg test. The training intervention also improved the running speed ability of the experimental group (P=0.003). No statistical differences were observed between lines or axes. Conclusion Additional combined training program between sprint repetition and vertical jump in the same training session positively influence the jumping ability and the sprint ability of handball players. PMID:22461962

The effect of a combined high-intensity plyometric and speed training program on the running and jumping ability of male handball players.

PubMed

Cherif, Monsef; Said, Mohamed; Chaatani, Sana; Nejlaoui, Olfa; Gomri, Daghbaji; Abdallah, Aouidet

2012-03-01

The aim of this study was to investigate the effect of a combined program including sprint repetitions and drop jump training in the same session on male handball players. Twenty-two male handball players aged more than 20 years were assigned into 2 groups: experimental group (n=11) and control group (n=11). Selection was based on variables "axis" and "lines", goalkeepers were not included. The experimental group was subjected to 2 testing periods (test and retest) separated by 12 weeks of an additional combined plyometric and running speed training program. The control group performed the usual handball training. The testing period comprised, at the first day, a medical checking, anthropometric measurements and an incremental exercise test called yo-yo intermittent recovery test. 2 days later, participants performed the Repeated Sprint Ability test (RSA), and performed the Jumping Performance using 3 different events: Squat jump (SJ), Countermovement jump without (CMJ) and with arms (CMJA), and Drop jump (DJ). At the end of the training period, participants performed again the repeated sprint ability test, and the jumping performance. The conventional combined program improved the explosive force ability of handball players in CMJ (P=0.01), CMJA (P=0.01) and DJR (P=0.03). The change was 2.78, 2.42 and 2.62% respectively. No significant changes were noted in performances of the experimental group at the squat jump test and the drop jump with the left leg test. The training intervention also improved the running speed ability of the experimental group (P=0.003). No statistical differences were observed between lines or axes. Additional combined training program between sprint repetition and vertical jump in the same training session positively influence the jumping ability and the sprint ability of handball players.

Colleges Making SAT Optional as Admissions Requirement

ERIC Educational Resources Information Center

Gilroy, Marilyn

2007-01-01

This article reports that more colleges are dropping the SAT as a requirement for admission and, in many cases, these institutions are attracting a larger and more diverse pool of applicants. According to the National Center for Fair & Open Testing (FairTest), 740 schools have made the SATs optional. The list includes some of the nation's most…

The Vertical Drop Jump Is a Poor Screening Test for ACL Injuries in Female Elite Soccer and Handball Players: A Prospective Cohort Study of 710 Athletes.

PubMed

Krosshaug, Tron; Steffen, Kathrin; Kristianslund, Eirik; Nilstad, Agnethe; Mok, Kam-Ming; Myklebust, Grethe; Andersen, Thor Einar; Holme, Ingar; Engebretsen, Lars; Bahr, Roald

2016-04-01

The evidence linking knee kinematics and kinetics during a vertical drop jump (VDJ) to anterior cruciate ligament (ACL) injury risk is restricted to a single small sample. Still, the VDJ test continues to be advocated for clinical screening purposes. To test whether 5 selected kinematic and kinetic variables were associated with future ACL injuries in a large cohort of Norwegian female elite soccer and handball players. Furthermore, we wanted to assess whether the VDJ test can be recommended as a screening test to identify players with increased risk. Cohort study; Level of evidence, 2. Elite female soccer and handball players participated in preseason screening tests from 2007 through 2014. The tests included marker-based 3-dimensional motion analysis of a drop-jump landing. We followed a predefined statistical protocol in which we included the following candidate risk factors in 5 separate logistic regression analyses, with new ACL injury as the outcome: (1) knee valgus angle at initial contact, (2) peak knee abduction moment, (3) peak knee flexion angle, (4) peak vertical ground-reaction force, and (5) medial knee displacement. A total of 782 players were tested (age, 21 ± 4 years; height, 170 ± 7 cm; body mass, 67 ± 8 kg), of which 710 were included in the analyses. We registered 42 new noncontact ACL injuries, including 12 in previously ACL-injured players. Previous ACL injury (relative risk, 3.8; 95% CI, 2.1-7.1) and medial knee displacement (odds ratio, 1.40; 95% CI, 1.12-1.74 per 1-SD change) were associated with increased risk for injury. However, among the 643 players without previous injury, we found no association with medial knee displacement. A receiver operating characteristic curve analysis of medial knee displacement showed an area under the curve of 0.6, indicating a poor-to-failed combined sensitivity and specificity of the test, even when including previously injured players. Of the 5 risk factors considered, medial knee displacement was the only factor associated with increased risk for ACL. However, receiver operating characteristic curve analysis indicated a poor combined sensitivity and specificity when medial knee displacement was used as a screening test for predicting ACL injury. For players with no previous injury, none of the VDJ variables were associated with increased injury risk. VDJ tests cannot predict ACL injuries in female elite soccer and handball players. © 2016 The Author(s).

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.

Forward Bay Cover Separation Modeling and Testing for the Orion Multi-Purpose Crew Vehicle

NASA Technical Reports Server (NTRS)

Ali, Yasmin; Chuhta, Jesse D.; Hughes, Michael P.; Radke, Tara S.

2015-01-01

Spacecraft multi-body separation events during atmospheric descent require complex testing and analysis to validate the flight separation dynamics models used to verify no re-contact. The NASA Orion Multi-Purpose Crew Vehicle (MPCV) architecture includes a highly-integrated Forward Bay Cover (FBC) jettison assembly design that combines parachutes and piston thrusters to separate the FBC from the Crew Module (CM) and avoid re-contact. A multi-disciplinary team across numerous organizations examined key model parameters and risk areas to develop a robust but affordable test campaign in order to validate and verify the FBC separation event for Exploration Flight Test-1 (EFT-1). The FBC jettison simulation model is highly complex, consisting of dozens of parameters varied simultaneously, with numerous multi-parameter interactions (coupling and feedback) among the various model elements, and encompassing distinct near-field, mid-field, and far-field regimes. The test campaign was composed of component-level testing (for example gas-piston thrusters and parachute mortars), ground FBC jettison tests, and FBC jettison air-drop tests that were accomplished by a highly multi-disciplinary team. Three ground jettison tests isolated the testing of mechanisms and structures to anchor the simulation models excluding aerodynamic effects. Subsequently, two air-drop tests added aerodynamic and parachute elements, and served as integrated system demonstrations, which had been preliminarily explored during the Orion Pad Abort-1 (PA-1) flight test in May 2010. Both ground and drop tests provided extensive data to validate analytical models and to verify the FBC jettison event for EFT-1. Additional testing will be required to support human certification of this separation event, for which NASA and Lockheed Martin are applying knowledge from Apollo and EFT-1 testing and modeling to develop a robust human-rated FBC separation event.

Design and testing of an energy-absorbing crewseat for the F/FB-111 aircraft. Volume 2: Data from seat testing

NASA Technical Reports Server (NTRS)

Shane, S. J.

1985-01-01

The unacceptably high injury rate during the escape sequence (including the ejection and ground impact) of the crew module for F/FB-111 aircraft is reviewed. A program to determine if the injury potential could be reduced by replacing the existing crewseats with energy absorbing crewseats is presented. An energy absorbing test seat is designed using much of the existing seat hardware. An extensive dynamic seat test series, designed to duplicate various crew module ground impact conditions is conducted at a sled test facility. Comparative tests with operational F-111 crewseats are also conducted. After successful dynamic testing of the seat, more testing is conducted with the seats mounted in an F-111 crew module. Both swing tests and vertical drop tests are conducted. The vertical drop tests are 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. Volume 2 presents the data obtained during the seat test series, while Volume 3 presents the data from the crew module test series.

Comparison analysis on the thermal runaway of lithium-ion battery under two heating modes.

PubMed

Wu, Tangqin; Chen, Haodong; Wang, Qingsong; Sun, Jinhua

2018-02-15

The thermal stability evaluation of materials in a soft-pack commercial cell is tested using C80 calorimeter, including anode, cathode, separator and full cell (mixing of the three materials including additional electrolyte). Thermal runaway characteristic of the commercial cell is tested on the accelerating rate calorimeter (ARC) with two heating modes, including internal heating mode and external heating mode. The results show that the thermal stability of internal material for tested cell follows the below order: anode

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.

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...

Constitutive Soil Properties for Mason Sand and Kennedy Space Center

NASA Technical Reports Server (NTRS)

Thomas, Michael A.; Chitty, Daniel E.

2011-01-01

Accurate soil models are required for numerical simulations of land landings for the Orion Crew Exploration Vehicle (CEV). This report provides constitutive material models for two soil conditions at Kennedy Space Center (KSC) and four conditions of Mason Sand. The Mason Sand is the test sand for LaRC s drop tests and swing tests of the Orion. The soil models are based on mechanical and compressive behavior observed during geotechnical laboratory testing of remolded soil samples. The test specimens were reconstituted to measured in situ density and moisture content. Tests included: triaxial compression, hydrostatic compression, and uniaxial strain. A fit to the triaxial test results defines the strength envelope. Hydrostatic and uniaxial tests define the compressibility. The constitutive properties are presented in the format of LSDYNA Material Model 5: Soil and Foam. However, the laboratory test data provided can be used to construct other material models. The soil models are intended to be specific to the soil conditions they were tested at. The two KSC models represent two conditions at KSC: low density dry sand and high density in-situ moisture sand. The Mason Sand model was tested at four conditions which encompass measured conditions at LaRC s drop test site.

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.

Experimental measurement of cooling tower emissions using image processing of sensitive papers

NASA Astrophysics Data System (ADS)

Ruiz, J.; Kaiser, A. S.; Ballesta, M.; Gil, A.; Lucas, M.

2013-04-01

Cooling tower emissions are harmful for several reasons such as air polluting, wetting, icing and solid particle deposition, but mainly due to human health hazards (i.e. Legionella). There are several methods for measuring drift drops. This paper is focussed on the sensitive paper technique, which is suitable in low drift scenarios and real conditions. The lack of an automatic classification method motivated the development of a digital image process algorithm for the Sensitive Paper method. This paper presents a detailed description of this method, in which, drop-like elements are identified by means of the Canny edge detector combined with some morphological operations. Afterwards, the application of a J48 decision tree is proposed as one of the most relevant contributions. This classification method allows us to discern between stains whose origin is a drop and stains whose origin is not a drop. The method is applied to a real case and results are presented in terms of drift and PM10 emissions. This involves the calculation of the main features of the droplet distribution at the cooling tower exit surface in terms of drop size distribution data, cumulative mass distribution curve and characteristic drop diameters. The Log-normal and the Rosin-Rammler distribution functions have been fitted to the experimental data collected in the tests and it can been concluded that the first one is the most suitable for experimental data among the functions tested (whereas the second one is less suitable). Realistic PM10 calculations include the measurement of drift emissions and Total Dissolved Solids as well as the size and number of drops. Results are compared to the method proposed by the U.S. Environmental Protection Agency assessing its overestimation. Drift emissions have found to be 0.0517% of the recirculating water, which is over the Spanish standards limit (0.05%).

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.

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.

A theoretical and experimental study of turbulent nonevaporating sprays

NASA Technical Reports Server (NTRS)

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

1984-01-01

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

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

NASA Technical Reports Server (NTRS)

McKenzie, Clifford; Parness, Aaron

2011-01-01

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

Characterization of Vertical Impact Device Acceleration Pulses Using Parametric Assessment: Phase IV Dual Impact Pulses

DTIC Science & Technology

2017-01-04

response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining...configurations with a restrained manikin, was evaluated in four different test series . Test Series 1 was conducted to determine the materials and...5 ms TTP. Test Series 2 was conducted to determine the materials and drop heights required for energy attenuation of the seat pan to generate a 4 m

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.

Space station common module thermal management: Design and construction of a test bed

NASA Technical Reports Server (NTRS)

Barile, R. G.

1986-01-01

In this project, a thermal test bed was designed, simulated, and planned for construction. The thermal system features interior and exterior thermal loads and interfacing with the central-radiator thermal bus. Components of the test bed include body mounted radiator loop with interface heat exchangers (600 Btu/hr); an internal loop with cabin air-conditioning and cold plates (3400 Btu/hr); interface heat exchangers to the central bus (13,000 Btu/hr); and provisions for new technology including advanced radiators, thermal storage, and refrigeration. The apparatus will be mounted in a chamber, heated with lamps, and tested in a vacuum chamber with LN2-cooled walls. Simulation of the test bed was accomplished using a DEC PRO 350 computer and the software package TK! olver. Key input variables were absorbed solar radiation and cold plate loads. The results indicate temperatures on the two loops will be nominal when the radiation and cold plate loads are in the range of 25% to 75% of peak loads. If all loads fall to zero, except the cabin air system which was fixed, the radiator fluid will drop below -100 F and may cause excessive pressure drop. If all loads reach 100%, the cabin air temperature could rise to 96 F.

Development of a Methodology to Conduct Usability Evaluation for Hand Tools that May Reduce the Amount of Small Parts that are Dropped During Installation while Processing Space Flight Hardware

NASA Technical Reports Server (NTRS)

Miller, Darcy

2000-01-01

Foreign object debris (FOD) is an important concern while processing space flight hardware. FOD can be defined as "The debris that is left in or around flight hardware, where it could cause damage to that flight hardware," (United Space Alliance, 2000). Just one small screw left unintentionally in the wrong place could delay a launch schedule while it is retrieved, increase the cost of processing, or cause a potentially fatal accident. At this time, there is not a single solution to help reduce the number of dropped parts such as screws, bolts, nuts, and washers during installation. Most of the effort is currently focused on training employees and on capturing the parts once they are dropped. Advances in ergonomics and hand tool design suggest that a solution may be possible, in the form of specialty hand tools, which secure the small parts while they are being handled. To assist in the development of these new advances, a test methodology was developed to conduct a usability evaluation of hand tools, while performing tasks with risk of creating FOD. The methodology also includes hardware in the form of a testing board and the small parts that can be installed onto the board during a test. The usability of new hand tools was determined based on efficiency and the number of dropped parts. To validate the methodology, participants were tested while performing a task that is representative of the type of work that may be done when processing space flight hardware. Test participants installed small parts using their hands and two commercially available tools. The participants were from three groups: (1) students, (2) engineers / managers and (3) technicians. The test was conducted to evaluate the differences in performance when using the three installation methods, as well as the difference in performance of the three participant groups.

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.

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...

[Predicting drop-out during the systems training for emotional predictability and problem solving (STEPPS)].

PubMed

van Diepen, J B; de Groot, I W

2016-01-01

Drop-out is a complex problem in mental health care and in STEPPS. Research has revealed a variety of predicting factors and has produced contradictory results. To investigate whether the information available at the start of STEPPS can pinpoint predictors of drop-out. The ROM data for 150 patients were used to test the link between the following factors: age, gender, education, employment, substance abuse, anxiety, hostility, interpersonal relations, responsibility and social concordance with drop-out. The method used for testing was logistic regression analysis. Factors that contributed significantly to the prediction of drop-out were gender and employment status. These factors made up 16% of the explained variation (R2 Nagelkerkes) in drop-out. Gender was the strongest predictive factor. Concerning the other factors, no differences were found between groups (drop-out and non-dropouts). In its present form STEPPS does not suit a large number of the male participants. Drop-out during STEPPS is hard to predict on the basis of ROM-questionnaires. Future research should focus on preconditions and marginal conditions that influence patients to complete their training.

Inertial Gait Phase Detection for control of a drop foot stimulator Inertial sensing for gait phase detection.

PubMed

Kotiadis, D; Hermens, H J; Veltink, P H

2010-05-01

An Inertial Gait Phase Detection system was developed to replace heel switches and footswitches currently being used for the triggering of drop foot stimulators. A series of four algorithms utilising accelerometers and gyroscopes individually and in combination were tested and initial results are shown. Sensors were positioned on the outside of the upper shank. Tests were performed on data gathered from a subject, sufferer of stroke, implanted with a drop foot stimulator and triggered with the current trigger, the heel switch. Data tested includes a variety of activities representing everyday life. Flat surface walking, rough terrain and carpet walking show 100% detection and the ability of the algorithms to ignore non-gait events such as weight shifts. Timing analysis is performed against the current triggering method, the heel switch. After evaluating the heel switch timing against a reference system, namely the Vicon 370 marker and force plates system. Initial results show a close correlation between the current trigger detection and the inertial sensor based triggering algorithms. Algorithms were tested for stairs up and stairs down. Best results are observed for algorithms using gyroscope data. Algorithms were designed using threshold techniques for lowest possible computational load and with least possible sensor components to minimize power requirements and to allow for potential future implantation of sensor system.

Vestibular evoked myogenic potential (VEMP) in patients with Ménière's disease with drop attacks.

PubMed

Timmer, Ferdinand C A; Zhou, Guangwei; Guinan, John J; Kujawa, Sharon G; Herrmann, Barbara S; Rauch, Steven D

2006-05-01

In this retrospective study, we tested the hypothesis that vestibular evoked myogenic potential (VEMP) thresholds are more often elevated or absent in patients with Ménière's disease experiencing Tumarkin drop attacks than in other patients with Ménière's disease. Subjects included normal subjects (n = 14) and patients with unilateral Ménière's disease by AAO-HNS (1995) diagnostic criteria with (n = 12) and without (n = 82) Tumarkin drop attacks at a large specialty hospital otology service. VEMP threshold testing was conducted using 250, 500, and 1,000 Hz tone burst stimuli. VEMP responses were present in at all frequencies in both ears of all normal subjects. In unaffected ears of patients with unilateral Ménière's disease, VEMPs were undetectable in 13% of measurements attempted. This number rose to 18% in affected ears of patients with unilateral Ménière's disease and to 41% in Meniere ears with Tumarkin drop attacks. Frequency tuning of the VEMP response in normal subjects showed lowest thresholds at 500 Hz. In Meniere ears, the tuning was altered such that the 500-Hz thresholds were higher than the 1,000-Hz thresholds. There was a gradient of threshold elevation and altered tuning that corresponded to the gradient of worsening disease. Our findings support the hypothesis that Tumarkin drop attacks arise from advanced disease involving the saccule and that VEMP may be a clinically valuable metric of disease severity or progression in patients with Ménière's disease.

The Predictive Validity of Using Admissions Testing and Multiple Mini-Interviews in Undergraduate University Admissions

ERIC Educational Resources Information Center

Makransky, Guido; Havmose, Philip; Vang, Maria Louison; Andersen, Tonny Elmose; Nielsen, Tine

2017-01-01

The aim of this study was to evaluate the predictive validity of a two-step admissions procedure that included a cognitive ability test followed by multiple mini-interviews (MMIs) used to assess non-cognitive skills, compared to grade-based admissions relative to subsequent drop-out rates and academic achievement after one and two years of study.…

TRACT 2 Frame Drop Test AT NASA Langley Research Center's Landin

NASA Image and Video Library

2014-05-09

(Tract)2 Transport Rotorcraft Airframe Crash Testbed; Full Frame Drop Test: rotary wing crash worthiness, impact research at NASA Langley Research Center's Landing and Impact Research (LandIR) Facility Building 1297

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

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.

Capabilities and constraints of NASA's ground-based reduced gravity facilities

NASA Technical Reports Server (NTRS)

Lekan, Jack; Neumann, Eric S.; Sotos, Raymond G.

1993-01-01

The ground-based reduced gravity facilities of NASA have been utilized to support numerous investigations addressing various processes and phenomina in several disciplines for the past 30 years. These facilities, which include drop towers, drop tubes, aircraft, and sounding rockets are able to provide a low gravity environment (gravitational levels that range from 10(exp -2)g to 10(exp -6)g) by creating a free fall or semi-free fall condition where the force of gravity on an experiment is offset by its linear acceleration during the 'fall' (drop or parabola). The low gravity condition obtained on the ground is the same as that of an orbiting spacecraft which is in a state of perpetual free fall. The gravitational levels and associated duration times associated with the full spectrum of reduced gravity facilities including spaced-based facilities are summarized. Even though ground-based facilities offer a relatively short experiment time, this available test time has been found to be sufficient to advance the scientific understanding of many phenomena and to provide meaningful hardware tests during the flight experiment development process. Also, since experiments can be quickly repeated in these facilities, multistep phenomena that have longer characteristic times associated with them can sometimes be examined in a step-by-step process. There is a large body of literature which has reported the study results achieved through using reduced-gravity data obtained from the facilities.

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.

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.

Anomalous Transport in Single-Well Push-Pull Tracer Tests

NASA Astrophysics Data System (ADS)

Chen, K.; Zhan, H.

2016-12-01

Single-Well Push-Pull (SWPP) tracer test was conducted to estimate the hydraulic and transport properties in a fractured aquifer at Newark basin. A common phenomenon observed for a set of SWPP tests with different incubation time is the heavy tailing of breakthrough curve (BTC) in pumping phase. A novel model with fractional-in-time and (or) -space was developed to interpret the anomalous transport behavior in SWPP tests. The fractal models, including fractional-in-time, fractional-in-space and fractional-in-time-and-space, were solved in radial coordinate using implicit Euler method. A semi-analytical solution of the mobile-immobile (MIM) model was derived as well for comparison purpose. It is found that the fractional-in-space and fractional-in-time-and-space models match the experimental data well. The BTC of the MIM model drops slower than that of the fractional-in-space model at the beginning of pumping and drops much faster at late time. The best match of fractional-in-space model with the experimental data demonstrates that the non-local transport in space plays an important role in SWPP tests conducted in fractured aquifers.

Properties of Controlled Low Strength Material with Circulating Fluidized Bed Combustion Ash and Recycled Aggregates

PubMed Central

Weng, Tsai-Lung; Cheng, An; Chao, Sao-Jeng; Hsu, Hui-Mi

2018-01-01

This study aims to investigate the effect of adding circulating fluidized bed combustion (CFBC) ash, desulfurization slag, air-cooled blast-furnace slag and coal bottom ash to the controlled low-strength material (CLSM). Test methods include slump flow test, ball drop test, water soluble chloride ion content measurement, compressive strength and length change measurement. The results show that (1) the use of CFBC hydration ash with desulfurization slag of slump flow is the best, and the use of CFBC hydration ash with coal bottom ash and slump flow is the worst; (2) CFBC hydration ash with desulfurization slag and chloride ion content is the highest; (3) 24 h ball drop test (diameter ≤ 76 mm), and test results are 70 mm to 76 mm; (4) CFBC hydration ash with desulfurization slag and compression strength is the highest, with the coal bottom ash being the lowest; increase of CFBC hydration ash can reduce compressive strength; and (5) the water-quenched blast furnace slag and CFBC hydration ash would expand, which results in length changes of CLSM specimens. PMID:29724055

Determination of selection criteria for spray drift reduction from atomization data

USDA-ARS?s Scientific Manuscript database

When testing and evaluating drift reduction technologies (DRT), there are different metrics that can be used to determine if the technology reduces drift as compared to a reference system. These metrics can include reduction in percent of fine drops, measured spray drift from a field trial, or comp...

Relationship of Personality Traits to Student Retention

ERIC Educational Resources Information Center

Liang, John Paul

2010-01-01

Carl Jung's theory of psychological types has been the basis for the development of personality categorization, including tests such as Myers-Briggs Type Indicator (MBTI). This study analyzed the extent of the relationship between MBTI and Tinto (1993) retention factors that influence Oriental medicine students' choice of staying or dropping out…

A programmable and portable NMES device for drop foot correction and blood flow assist applications.

PubMed

Breen, Paul P; Corley, Gavin J; O'Keeffe, Derek T; Conway, Richard; Olaighin, Gearóid

2009-04-01

The Duo-STIM, a new, programmable and portable neuromuscular stimulation system for drop foot correction and blood flow assist applications is presented. The system consists of a programmer unit and a portable, programmable stimulator unit. The portable stimulator features fully programmable, sensor-controlled, constant-voltage, dual-channel stimulation and accommodates a range of customized stimulation profiles. Trapezoidal and free-form adaptive stimulation intensity envelope algorithms are provided for drop foot correction applications, while time dependent and activity dependent algorithms are provided for blood flow assist applications. A variety of sensor types can be used with the portable unit, including force sensitive resistor-based foot switches and MEMS-based accelerometer and gyroscope devices. The paper provides a detailed description of the hardware and block-level system design for both units. The programming and operating procedures for the system are also presented. Finally, functional bench test results for the system are presented.

A programmable and portable NMES device for drop foot correction and blood flow assist applications.

PubMed

Breen, Paul P; Corley, Gavin J; O'Keeffe, Derek T; Conway, Richard; OLaighin, Gearoid

2007-01-01

The Duo-STIM, a new, programmable and portable neuromuscular stimulation system for drop foot correction and blood flow assist applications is presented. The system consists of a programmer unit and a portable, programmable stimulator unit. The portable stimulator features fully programmable, sensor-controlled, constant-voltage, dual-channel stimulation and accommodates a range of customized stimulation profiles. Trapezoidal and free-form adaptive stimulation intensity envelope algorithms are provided for drop foot correction applications, while time dependent and activity dependent algorithms are provided for blood flow assist applications. A variety of sensor types can be used with the portable unit, including force sensitive resistor based foot switches and NMES based accelerometer and gyroscope devices. The paper provides a detailed description of the hardware and block-level system design for both units. The programming and operating procedures for the system are also presented. Finally, functional bench test results for the system are presented.

Estimation of dynamic stability parameters from drop model flight tests

NASA Technical Reports Server (NTRS)

Chambers, J. R.; Iliff, K. W.

1981-01-01

A recent NASA application of a remotely-piloted drop model to studies of the high angle-of-attack and spinning characteristics of a fighter configuration has provided an opportunity to evaluate and develop parameter estimation methods for the complex aerodynamic environment associated with high angles of attack. The paper discusses the overall drop model operation including descriptions of the model, instrumentation, launch and recovery operations, piloting concept, and parameter identification methods used. Static and dynamic stability derivatives were obtained for an angle-of-attack range from -20 deg to 53 deg. The results of the study indicated that the variations of the estimates with angle of attack were consistent for most of the static derivatives, and the effects of configuration modifications to the model (such as nose strakes) were apparent in the static derivative estimates. The dynamic derivatives exhibited greater uncertainty levels than the static derivatives, possibly due to nonlinear aerodynamics, model response characteristics, or additional derivatives.

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.

Development of technology for the fabrication of reliable laminar flow control panels on subsonic transports

NASA Technical Reports Server (NTRS)

1976-01-01

The feasibility of using porous composite materials (Kevlar, Doweave, and Leno Weave) as lightweight, efficient laminar flow control (LFC) surface materials is compared to the metallic 319L stainless Dynapore surfaces and electron beam drilled composite surfaces. Areas investigated include: (1) selection of the LFC-suitable surface materials, structural materials, and fabrication techniques for the LFC aircraft skins; (2) aerodynamic static air flow test results in terms of pressure drop through the LFC panel and the corresponding effective porosity; (3) structural design definition and analyses of the panels, and (4) contamination effects on static drop and effective porosity. Conclusions are presented and discussed.

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...

Evaluation of Off-season Potential Breeding Sources for Spotted Wing Drosophila (Drosophila suzukii Matsumura) in Michigan.

PubMed

Bal, Harit K; Adams, Christopher; Grieshop, Matthew

2017-12-05

It has been suggested that fruit wastes including dropped and unharvested fruits, and fruit byproducts (i.e., pomace) found in fruit plantings and cideries or wine-making facilities could serve as potential off-season breeding sites for spotted wing Drosophila (Drosophila suzukii Matsumura (Diptera: Drosophilidae)). This idea, however, has yet to be widely tested. The goal of our study was to determine the potential of dropped fruit and fruit wastes as Fall spotted wing Drosophila breeding resources in Michigan, USA. Fruit waste samples were collected from 15 farms across the lower peninsula of Michigan and were evaluated for spotted wing Drosophila and other drosophilid emergence and used in host suitability bioassays. All of the dropped apples, pears, grapes, and raspberries and 40% of apple and 100% of grape fruit pomace evaluated were found to contain spotted wing Drosophila with the highest numbers collected from dropped grapes and pears. Greater spotted wing Drosophila recovery was found in fruit wastes at sites attached with cideries and wine-making facilities and with multiple cultivated fruit crops than sites with no cideries and only one crop. Females oviposited in raspberry, pear, apple, grape, apple pomace and grape pomace samples with the highest rates of reproduction in raspberries. Our results demonstrate that fruit wastes including dropped berry, pomme and stone fruits, as well as fruit compost may be important late season reproductive resources for spotted wing Drosophila. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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.

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.

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.

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.

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.

Sandia National Laboratories, Tonopah Test Range Askania Tower (Building 02-00): Photographs and Written Historical and Descriptive Data

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

Ullrich, Rebecca A.

The Askania Tower (Building 02-00) was built in 1956 as part of the first wave of construction at the newly established Tonopah Test Range (TTR). Located at Station 2, near the primary target area at the range, the tower was one of the first four built to house Askania phototheodolites used in tracking test units dropped from aircraft. This report includes historical information, architectural information, sources of information, project information, maps, blueprints, and photographs.

Size Distribution and Velocity of Ethanol Drops in a Rocket Combustor Burning Ethanol and Liquid Oxygen

NASA Technical Reports Server (NTRS)

Ingebo, Robert D.

1961-01-01

Single jets of ethanol were studied photomicrographically inside a rocket chamber as they broke up into sprays of drops which underwent simultaneous acceleration and vaporization with chemical reaction occurring in the surrounding combustion gas stream. In each rocket test-firing, liquid oxygen was used as the oxidant. Both drop velocity and drop size distribution data were obtained from photomicrographs of the ethanol drops taken with an ultra-high speed tracking camera developed at NASA, Lewis Research Center.

Acoustic Levitation and its Applications in the Study of Liquid Surface Rheology.

NASA Astrophysics Data System (ADS)

Tian, Yuren

Due to its non-contact manipulation and requirement of small amounts of test sample, acoustical levitation has been used to investigate the interfacial dynamics of liquids. In this current work, the surface rheology of liquid drops levitated in air has been studied. The surrounding of a gaseous medium simplifies the theoretical analysis and the interpretation of experimental results. For a ground-based experiment, the effect of gravity and the levitation sound field can change a levitated drop into a nonspherical shape. A theory which involves the multiple interactions between the drop and the sound field, the acoustic scattering by a nonspherical object and the limitation of droplet volume variation is developed. The droplet aspect ratio is determined as a function of the sound pressure, frequency (or wavelength) and the surface tension of liquid under both zero and nonzero gravity environments. The dynamics of a liquid drop of surfactant solution is also theoretically analyzed by including the different surfactant transfer processes at the droplet surface. The approximate solutions of the resonance frequency and damping constant of droplet free quadrupole shape oscillation are derived analytically and verified with the exact numerical solutions. The phase relationship between the driving force and the droplet response is established for the case of forced droplet shape oscillation. The surface viscoelasticity of liquid has shown a strong effect on the droplet dynamics. An acoustic levitation apparatus is constructed and used to levitate a liquid drop in air. By gauging the static shape of the drop versus its spatial location, the equilibrium surface tension of the liquid can be determined. The surface elasticity and viscosity are evaluated from the measurements of the resonance frequency, damping constant and phase relationship of the droplet quadrupole shape oscillation. Different kind of liquids are tested. For surfactant solutions, the experimental results illustrate the existence of surface viscoelasticities.

Experimental Investigation of two-phase nitrogen Cryo transfer line

NASA Astrophysics Data System (ADS)

Singh, G. K.; Nimavat, H.; Panchal, R.; Garg, A.; Srikanth, GLN; Patel, K.; Shah, P.; Tanna, V. L.; Pradhan, S.

2017-02-01

A 6-m long liquid nitrogen based cryo transfer line has been designed, developed and tested at IPR. The test objectives include the thermo-hydraulic characteristics of Cryo transfer line under single phase as well as two phase flow conditions. It is always easy in experimentation to investigate the thermo-hydraulic parameters in case of single phase flow of cryogen but it is real challenge when one deals with the two phase flow of cryogen due to availibity of mass flow measurements (direct) under two phase flow conditions. Established models have been reported in the literature where one of the well-known model of Lockhart-Martenelli relationship has been used to determine the value of quality at the outlet of Cryo transfer line. Under homogenous flow conditions, by taking the ratio of the single-phase pressure drop and the two-phase pressure drop, we estimated the quality at the outlet. Based on these equations, vapor quality at the outlet of the transfer line was predicted at different heat loads. Experimental rresults shown that from inlet to outlet, there is a considerable increment in the pressure drop and vapour quality of the outlet depending upon heat load and mass flow rate of nitrogen flowing through the line.

Some new tests at the Gottingen laboratory

NASA Technical Reports Server (NTRS)

1921-01-01

The tests at the Gottingen laboratory included: friction tests on a surface treated with omelette, verification tests on the M.V.A. 356 wing, and comparative tests of wing no. 36 at the Eiffel laboratory. The examination of all these experiments leads to the belief that, at large incidences, the speeds registered by the suction manometer of the testing chamber of the Eiffel laboratory wind tunnel are, owing to pressure drop, greater than the actual speeds. Therefore, the values of k(sub x) and k(sub y) measured at the Eiffel laboratory at large incidences are too low.

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

Log-normal spray drop distribution...analyzed by two new computer programs

Treesearch

Gerald S. Walton

1968-01-01

Results of U.S. Forest Service research on chemical insecticides suggest that large drops are not as effective as small drops in carrying insecticides to target insects. Two new computer programs have been written to analyze size distribution properties of drops from spray nozzles. Coded in Fortran IV, the programs have been tested on both the CDC 6400 and the IBM 7094...

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.

Multiple Off-Ice Performance Variables Predict On-Ice Skating Performance in Male and Female Division III Ice Hockey Players.

PubMed

Janot, Jeffrey M; Beltz, Nicholas M; Dalleck, Lance D

2015-09-01

The purpose of this study was to determine if off-ice performance variables could predict on-ice skating performance in Division III collegiate hockey players. Both men (n = 15) and women (n = 11) hockey players (age = 20.5 ± 1.4 years) participated in the study. The skating tests were agility cornering S-turn, 6.10 m acceleration, 44.80 m speed, modified repeat skate, and 15.20 m full speed. Off-ice variables assessed were years of playing experience, height, weight and percent body fat and off-ice performance variables included vertical jump (VJ), 40-yd dash (36.58m), 1-RM squat, pro-agility, Wingate peak power and peak power percentage drop (% drop), and 1.5 mile (2.4km) run. Results indicated that 40-yd dash (36.58m), VJ, 1.5 mile (2.4km) run, and % drop were significant predictors of skating performance for repeat skate (slowest, fastest, and average time) and 44.80 m speed time, respectively. Four predictive equations were derived from multiple regression analyses: 1) slowest repeat skate time = 2.362 + (1.68 x 40-yd dash time) + (0.005 x 1.5 mile run), 2) fastest repeat skate time = 9.762 - (0.089 x VJ) - (0.998 x 40-yd dash time), 3) average repeat skate time = 7.770 + (1.041 x 40-yd dash time) - (0.63 x VJ) + (0.003 x 1.5 mile time), and 4) 47.85 m speed test = 7.707 - (0.050 x VJ) - (0.01 x % drop). It was concluded that selected off-ice tests could be used to predict on-ice performance regarding speed and recovery ability in Division III male and female hockey players. Key pointsThe 40-yd dash (36.58m) and vertical jump tests are significant predictors of on-ice skating performance specific to speed.In addition to 40-yd dash and vertical jump, the 1.5 mile (2.4km) run for time and percent power drop from the Wingate anaerobic power test were also significant predictors of skating performance that incorporates the aspect of recovery from skating activity.Due to the specificity of selected off-ice variables as predictors of on-ice performance, coaches can elect to assess player performance off-ice and focus on other uses of valuable ice time for their individual teams.

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.

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.

Modeling the Restraint of Liquid Jets by Surface Tension in Microgravity

NASA Technical Reports Server (NTRS)

Chato, David J.; Jacqmim, David A.

2001-01-01

An axisymmetric phase field model is developed and used to model surface tension forces on liquid jets in microgravity. The previous work in this area is reviewed and a baseline drop tower experiment selected 'for model comparison. A mathematical model is developed which includes a free surface. a symmetric centerline and wall boundaries with given contact angles. The model is solved numerically with a compact fourth order stencil on a equally spaced axisymmetric grid. After grid convergence studies, a grid is selected and all drop tower tests modeled. Agreement was assessed by comparing predicted and measured free surface rise. Trend wise agreement is good but agreement in magnitude is only fair. Suspected sources of disagreement are suspected to be lack of a turbulence model and the existence of slosh baffles in the experiment which were not included in the model.

Inelastic deformation and damage at high temperature

NASA Astrophysics Data System (ADS)

Krempl, E.

1992-06-01

Combined experimental and theoretical investigations into the inelastic deformation and damage behavior of engineering alloys at elevated temperatures are being pursued. The analysis of previously performed strain rate change and relaxation tests on modified 9Cr-1Mo steel showed the need for inclusion of a recovery of state term in the growth laws for the state variables of the viscoplasticity theory based on overstress (VBO). Recovery of state terms were introduced and the experimental results were satisfactorily simulated. The finite deformation theory of VBO has been developed further to include a convected derivative rationale for the choice of the objective stress rate. The reversing direct current voltage drop measurements during low cycle fatigue at elevated temperature were improved. A passive filter bank and new positioning devices for the coils were installed. Tests at 650 C and lasting several days showed excessive, uncontrollable temperature changes. It was decided to drop the test temperature to 538 C which is close to the operating temperature of type 304 stainless steel. The temperature fluctuations in torsion tests were within +/- 3 C which was considered satisfactory.

Validation of CTF Droplet Entrainment and Annular/Mist Closure Models using Riso Steam/Water Experiments

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

Wysocki, Aaron J.; Salko, Robert K.

This report summarizes the work done to validate the droplet entrainment and de-entrainment models as well as two-phase closure models in the CTF code by comparison with experimental data obtained at Riso National Laboratory. The Riso data included a series of over 250 steam/water experiments that were performed in both tube and annulus geometries over a range of various pressures and outlet qualities. Experimental conditions were set so that the majority of cases were in the annular/mist ow regime. Measurements included liquid lm ow rate, droplet ow rate, lm thickness, and two-phase pressure drop. CTF was used to model 180more » of the tubular geometry cases, matching experimental geometry, outlet pressure, and outlet ow quality to experimental values. CTF results were compared to the experimental data at the outlet of the test section in terms of vapor and entrained liquid ow fractions, pressure drop per unit length, and liquid lm thickness. The entire process of generating CTF input decks, running cases, extracting data, and generating comparison plots was scripted using Python and Matplotlib for a completely automated validation process. All test cases and scripting tools have been committed to the COBRA-TF master repository and selected cases have been added to the continuous testing system to serve as regression tests. The dierences between the CTF- and experimentally-calculated ow fraction values were con- sistent with previous calculations by Wurtz, who applied the same entrainment correlation to the same data. It has been found that CTF's entrainment/de-entrainment predictive capability in the annular/mist ow regime for this particular facility is comparable to the licensed industry code, COBRAG. While lm and droplet predictions are generally good, it has been found that accuracy is diminished at lower ow qualities. This nding is consistent with the noted deciencies in the Wurtz entrainment model employed by CTF. The CTF predicted two-phase pressure drop in the annular/mist ow regime has been found to be highly inaccurate, exhibiting a clear bias with respect to the experimental data. This inaccuracy led to an investigation that revealed deciencies in the implementation of the annular/mist interfacial friction model, which should be investigated further in the future. Looking to published COBRAG results for this same facility reveal it exhibits no bias with regard to experimental pressure drop results. In addition to the problems with pressure drop prediction, the lm thickness was also signicantly under-predicted by CTF compared to both experimental data and Wurtz's analytical calculations. Film thickness is calculated using a simple geometric relationship and lm void fraction in CTF, which is dependent on slip ratio and interfacial friction. It is possible that the issues aecting the pressure drop and lm void prediction are related.« less

76 FR 9449 - National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-17

... chemistry, scrubber pressure drop, and scrubber inlet gas temperature hourly. The final rule does not... pressure) and inlet gas temperature to be based on the minimum flow rate (or line pressure) or maximum inlet gas temperature established during the initial performance test. It also includes two additional...

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.

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.

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.

Understanding the Importance of the Teres Minor for Shoulder Function: Functional Anatomy and Pathology.

PubMed

Williams, Matthew D; Edwards, Thomas Bradley; Walch, Gilles

2018-03-01

Although the teres minor is often overlooked in a normal shoulder, it becomes a key component in maintaining shoulder function when other rotator cuff tendons fail. The teres minor maintains a balanced glenohumeral joint and changes from an insignificant to the most significant external rotator in the presence of major rotator cuff pathology. The presence or absence of the teres minor provides prognostic information on the outcomes of reverse total shoulder arthroplasty and tendon transfers. Clinical tests include the Patte test, the Neer dropping sign, the external rotation lag sign, and the Hertel drop sign. Advanced imaging of the teres minor can be used for classification using the Walch system. Understanding the function and pathology surrounding the teres minor is paramount in comprehensive management of the patient with shoulder pathology. Appropriate clinical examination and imaging of the teres minor are important for preoperative stratification and postoperative expectations.

Crashworthiness of the AT-400A shipping container

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

Gruda, J.D.; York, A.R. II

1996-05-01

Shipping containers used for transporting radioactive material must be certified using federal regulations. These regulations require the container be tested or evaluated in severe mechanical and thermal environments which represent hypothetical accident scenarios. The containers are certified if the inner container remains leaktight. This paper presents results from finite element simulations of the accidents which include subjecting the AT-400A (for Pu from dismantled nuclear weapons) to a 30-foot (9 m) drop onto an unyielding target and crushing the container with an 1100 lb (500 kg) steel plate dropped from 30 feet. The nonlinear PRONTO3D finite element results were validated usingmore » test results. The simulations of the various impacts and crushes identified trends and worst-case orientations. They also showed that there is a significant margin of safety based on the failure of the containment vessel.« less

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...

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.

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

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?

Insights from the pollination drop proteome and the ovule transcriptome of Cephalotaxus at the time of pollination drop production

PubMed Central

Pirone-Davies, Cary; Prior, Natalie; von Aderkas, Patrick; Smith, Derek; Hardie, Darryl; Friedman, William E.; Mathews, Sarah

2016-01-01

Background and Aims Many gymnosperms produce an ovular secretion, the pollination drop, during reproduction. The drops serve as a landing site for pollen, but also contain a suite of ions and organic compounds, including proteins, that suggests diverse roles for the drop during pollination. Proteins in the drops of species of Chamaecyparis, Juniperus, Taxus, Pseudotsuga, Ephedra and Welwitschia are thought to function in the conversion of sugars, defence against pathogens, and pollen growth and development. To better understand gymnosperm pollination biology, the pollination drop proteomes of pollination drops from two species of Cephalotaxus have been characterized and an ovular transcriptome for C. sinensis has been assembled. Methods Mass spectrometry was used to identify proteins in the pollination drops of Cephalotaxus sinensis and C. koreana. RNA-sequencing (RNA-Seq) was employed to assemble a transcriptome and identify transcripts present in the ovules of C. sinensis at the time of pollination drop production. Key Results About 30 proteins were detected in the pollination drops of both species. Many of these have been detected in the drops of other gymnosperms and probably function in defence, polysaccharide metabolism and pollen tube growth. Other proteins appear to be unique to Cephalotaxus, and their putative functions include starch and callose degradation, among others. Together, the proteins appear either to have been secreted into the drop or to occur there due to breakdown of ovular cells during drop production. Ovular transcripts represent a wide range of gene ontology categories, and some may be involved in drop formation, ovule development and pollen–ovule interactions. Conclusions The proteome of Cephalotaxus pollination drops shares a number of components with those of other conifers and gnetophytes, including proteins for defence such as chitinases and for carbohydrate modification such as β-galactosidase. Proteins likely to be of intracellular origin, however, form a larger component of drops from Cephalotaxus than expected from studies of other conifers. This is consistent with the observation of nucellar breakdown during drop formation in Cephalotaxus. The transcriptome data provide a framework for understanding multiple metabolic processes that occur within the ovule and the pollination drop just before fertilization. They reveal the deep conservation of WUSCHEL expression in ovules and raise questions about whether any of the S-locus transcripts in Cephalotaxus ovules might be involved in pollen–ovule recognition. PMID:27045089

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.

Interrelating the breakage and composition of mined and drill core coal

NASA Astrophysics Data System (ADS)

Wilson, Terril Edward

Particle size distribution of coal is important if the coal is to be beneficiated, or if a coal sales contract includes particle size specifications. An exploration bore core sample of coal ought to be reduced from its original cylindrical form to a particle size distribution and particle composition that reflects, insofar as possible, a process stream of raw coal it represents. Often, coal cores are reduced with a laboratory crushing machine, the product of which does not match the raw coal size distribution. This study proceeds from work in coal bore core reduction by Australian investigators. In this study, as differentiated from the Australian work, drop-shatter impact breakage followed by dry batch tumbling in steel cylinder rotated about its transverse axis are employed to characterize the core material in terms of first-order and zeroth-order breakage rate constants, which are indices of the propensity of the coal to degrade during excavation and handling. Initial drop-shatter and dry tumbling calibrations were done with synthetic cores composed of controlled low-strength concrete incorporating fly ash (as a partial substitute for Portland cement) in order to reduce material variables and conserve difficult-to-obtain coal cores. Cores of three different coalbeds--Illinois No. 6, Upper Freeport, and Pocahontas No. 5 were subjected to drop-shatter and dry batch tumbling tests to determine breakage response. First-order breakage, characterized by a first-order breakage index for each coal, occurred in the drop-shatter tests. First- and zeroth-order breakage occurred in dry batch tumbling; disappearance of coarse particles and creation of fine particles occurred in a systematic way that could be represented mathematically. Certain of the coal cores available for testing were dry and friable. Comparison of coal preparation plant feed with a crushed bore core and a bore core prepared by drop-shatter and tumbling (all from the same Illinois No.6 coal mining property) indicated that the size distribution and size fraction composition of the drop-shattered/tumbled core more closely resembled the plant feed than the crushed core. An attempt to determine breakage parameters (to allow use of selection and breakage functions and population balance models in the description of bore core size reduction) was initiated. Rank determination of the three coal types was done, indicating that higher rank associates with higher breakage propensity. The two step procedure of drop-shatter and dry batch tumbling simulates the first-order (volume breakage) and zeroth-order (abrasion of particle surfaces) that occur in excavation and handling operations, and is appropriate for drill core reduction prior to laboratory analysis.

Effect of airstream velocity on mean drop diameters of water sprays produced by pressure and air atomizing nozzles. [for combustion studies

NASA Technical Reports Server (NTRS)

Ingebo, R. D.

1977-01-01

A scanning radiometer was used to determine the effect of airstream velocity on the mean drop diameter of water sprays produced by pressure atomizing and air atomizing fuel nozzles used in previous combustion studies. Increasing airstream velocity from 23 to 53.4 meters per second reduced the Sauter mean diameter by approximately 50 percent with both types of fuel nozzles. The use of a sonic cup attached to the tip of an air assist nozzle reduced the Sauter mean diameter by approximately 40 percent. Test conditions included airstream velocities of 23 to 53.4 meters per second at 293 K and atmospheric pressure.

Effect of airstream velocity on mean drop diameters of water sprays produced by pressure and air atomizing nozzles

NASA Technical Reports Server (NTRS)

Ingebo, R. D.

1977-01-01

A scanning radiometer was used to determine the effect of airstream velocity on the mean drop diameter of water sprays produced by pressure atomizing and air atomizing fuel nozzles used in previous combustion studies. Increasing airstream velocity from 23 to 53.4 meters per second reduced the Sauter mean diameter by approximately 50 percent with both types of fuel nozzles. The use of a sonic cup attached to the tip of an air assist nozzle reduced the Sauter mean diameter by approximately 40 percent. Test conditions included airstream velocities of 23 to 53.4 meters per second at 293 K and atmospheric pressure.

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

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.

Maximizing coupling strength of magnetically anchored surgical instruments: how thick can we go?

PubMed

Best, Sara L; Bergs, Richard; Gedeon, Makram; Paramo, Juan; Fernandez, Raul; Cadeddu, Jeffrey A; Scott, Daniel J

2011-01-01

The Magnetic Anchoring and Guidance System (MAGS) includes an external magnet that controls intra-abdominal surgical instruments via magnetic attraction forces. We have performed NOTES (Natural Orifice Transluminal Endoscopic Surgery) and LESS (Laparoendoscopic Single Site) procedures using MAGS instruments in porcine models with up to 2.5-cm-thick abdominal walls, but this distance may not be sufficient in some humans. The purpose of this study was to determine the maximal abdominal wall thickness for which the current MAGS platform is suitable. Successive iterations of prototype instruments were developed; those evaluated in this study include external (134-583 g, 38-61 mm diameter) and internal (8-39 g, 10-22 mm diameter) components using various grades, diameters, thicknesses, and stacking/shielding/focusing configurations of permanent Neodymium-iron-boron (NdFeB) magnets. Nine configurations were tested for coupling strength across distances of 0.1-10 cm. The force-distance tests across an air medium were conducted at 0.5-mm increments using a robotic arm fitted with a force sensor. A minimum theoretical instrument drop-off (decoupling) threshold was defined as the separation distance at which force decreased below the weight of the heaviest internal component (39 g). Magnetic attraction forces decreased exponentially over distance. For the nine configurations tested, the average forces were 3,334 ± 1,239 gf at 0.1 cm, 158 ± 98 gf at 2.5 cm, and 8.7 ± 12 gf at 5 cm; the drop-off threshold was 3.64 ± 0.8 cm. The larger stacking configurations and magnets yielded up to a 592% increase in attraction force at 2.5 cm and extended the drop-off threshold distance by up to 107% over single-stack anchors. For the strongest configuration, coupling force ranged from 5,337 gf at 0.1 cm to 0 gf at 6.95 cm and yielded a drop-off threshold distance of 4.78 cm. This study suggests that the strongest configuration of currently available MAGS instruments is suitable for clinically relevant abdominal wall thicknesses. Further platform development and optimization are warranted.

Evaluation of lower limb kinetics during gait, sprint and hop tests before and after anterior cruciate ligament reconstruction.

PubMed

Moya-Angeler, Joaquín; Vaquero, Javier; Forriol, Francisco

2017-06-01

The purpose of this study was to evaluate the functional status prior to and at different times after anterior cruciate ligament reconstruction (ACLR), and to analyze the changes in the kinetic patterns of the involved and uninvolved lower limb during gait, sprint and three hop tests. Seventy-four male patients with an ACL injury were included in the study. All patients performed a standardized kinetic protocol including gait, sprint and three hop tests (single-leg hop, drop vertical jump and vertical jump tests), preoperatively and at 3, 6, and 12 months after ACLR with a semitendinosus gracilis tendon autograft. Measurements were performed with two force plates. The lower limb symmetry index (LSI) was calculated to determine whether a side-to-side leg difference was classified as normal (LSI >90%) or abnormal (LSI <90%). The LSI presented high values (>90%) at almost all times before and after ACLR in gait, sprint and single-leg hop tests (p < 0.005), with a tendency to increase postoperatively. A lower LSI was observed (<90%) in tests where both extremities were tested simultaneously, such as the drop vertical jump and vertical hop tests (p < 0.05). We observed a tendency to increase symmetry restoration in the kinetics of the involved and uninvolved limb up to twelve months after ACLR, especially in those tests, in which, both limbs were tested individually (gait analysis, sprint and single-leg hop tests). Therefore, the isolation of the involved and uninvolved limb seems to be a critical component in the functional rehabilitation and evaluation of patients before and after ACLR. level III.

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.

On-sun testing of an advanced falling particle receiver system

NASA Astrophysics Data System (ADS)

Ho, Clifford K.; Christian, Joshua M.; Yellowhair, Julius; Siegel, Nathan; Jeter, Sheldon; Golob, Matthew; Abdel-Khalik, Said I.; Nguyen, Clayton; Al-Ansary, Hany

2016-05-01

A 1 MWth high-temperature falling particle receiver was constructed and tested at the National Solar Thermal Test Facility at Sandia National Laboratories. The continuously recirculating system included a particle elevator, top and bottom hoppers, and a cavity receiver that comprised a staggered array of porous chevron-shaped mesh structures that slowed the particle flow through the concentrated solar flux. Initial tests were performed with a peak irradiance of ~300 kW/m2 and a particle mass flow rate of 3.3 kg/s. Peak particle temperatures reached over 700 °C near the center of the receiver, but the particle temperature increase near the sides was lower due to a non-uniform irradiance distribution. At a particle inlet temperature of ~440 °C, the particle temperature increase was 27 °C per meter of drop length, and the thermal efficiency was ~60% for an average irradiance of 110 kW/m2. At an average irradiance of 211 kW/m2, the particle temperature increase was 57.1 °C per meter of drop length, and the thermal efficiency was ~65%. Tests with higher irradiances are being performed and are expected to yield greater particle temperature increases and efficiencies.

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.

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

NASA Technical Reports Server (NTRS)

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

1988-01-01

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

Drop-on-Demand System for Manufacturing of Melt-based Solid Oral Dosage: Effect of Critical Process Parameters on Product Quality.

PubMed

Içten, Elçin; Giridhar, Arun; Nagy, Zoltan K; Reklaitis, Gintaras V

2016-04-01

The features of a drop-on-demand-based system developed for the manufacture of melt-based pharmaceuticals have been previously reported. In this paper, a supervisory control system, which is designed to ensure reproducible production of high quality of melt-based solid oral dosages, is presented. This control system enables the production of individual dosage forms with the desired critical quality attributes: amount of active ingredient and drug morphology by monitoring and controlling critical process parameters, such as drop size and product and process temperatures. The effects of these process parameters on the final product quality are investigated, and the properties of the produced dosage forms characterized using various techniques, such as Raman spectroscopy, optical microscopy, and dissolution testing. A crystallization temperature control strategy, including controlled temperature cycles, is presented to tailor the crystallization behavior of drug deposits and to achieve consistent drug morphology. This control strategy can be used to achieve the desired bioavailability of the drug by mitigating variations in the dissolution profiles. The supervisor control strategy enables the application of the drop-on-demand system to the production of individualized dosage required for personalized drug regimens.

Different behavioural responses of larval fish under microgravity and morphological correlates in the inner ear -a drop-tower study

NASA Astrophysics Data System (ADS)

Hilbig, Reinhard; Weigele, Jochen; Knie, Miriam; Hendrik Anken, Ralf

In vertebrates altered gravitational environments such as weightlessness (microgravity, g) in-duce changes in central and peripheral interpretation of sensory input leading to alterations in motor behaviour (e.g., intersensory-conflicts) including space motion sickness, a sensory motor kinetosis normally accompanied by malaise and vomiting. In fish it had been repeatedly shown that some fish of a given batch reveal motion sickness after transition from hypergravity (pull up) to microgravity microgravity in the course of parabolic aircraft flight (PF= low quality microgravity = LQM) experiments or in the case of drop tower experiments at ZARM (Bre-men) immediately after release of the capsule. The drop-tower studies were designed to further elucidate the role of otolith asymmetry concerning an individually different susceptibility to kinetoses. In order to test, whether the differing results between the PF and the drop-tower experiment were based exclusively on the differing quality of diminished gravity, or, if further parameters of the PF and the drop-tower environment need to be taken into consideration (e.g., vibrations and changing accelerations during PFs or the brisk compression of the drop-capsule at its release) to explain the differing results, drop-tower flights were performed at a series of increasing accelerations, by centrifugation in the drop capsule. This simulation of "differ-ent micro" gravity was carried out in housing larval cichlid fish (Oreochromis mossambicus) within a centrifuge at high quality microgravity 10-6g (HQM) and 10-4g to 0.3g during the drop-tower flights. The percentual ratios of the swimming behaviour at drop-tower changed significantly according to the increasing acceleration force of the centrifuge during flight. With increasing acceleration (= detectable gravity for fish) the relative proportion of looping an d spinning movements decreased in favour of normal swimming an at 0.3g nearly no kinetotic behaviour was observed. When during centrifugation in the drop-tower capsule LQM ranged between those of PF LQM the fish displayed comparable types of behaviour (normal and kine-totic swimming). This indicates that some normally swimming fish during PFs and drop-tower LQM use the residual gravity as a cue for orientation. Whereas kinetoses were exhibited by some 90 The present findings on otolith asymmetry support the concept, according to which kinetosis susceptibility is based on highly asymmetric inner ear stones.

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

USDA-ARS?s Scientific Manuscript database

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

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.

Custom Unit Pump Development for the EVA PLSS

NASA Technical Reports Server (NTRS)

Schuller, Michael; Kurwitz, Cable; Little, Frank; Oinuma, Ryoji; Larsen, Ben; Goldman, Jeff; Reinis, Filip; Trevino, Luis

2010-01-01

This paper describes the effort by the Texas Engineering Experiment Station (TEES) and Honeywell for NASA to design and test a pre-flight prototype pump for use in the Extra-vehicular activity (EVA) portable life support subsystem (PLSS). Major design decisions were driven by the need to reduce the pump s mass, power, and volume compared to the existing PLSS pump. In addition, the pump must accommodate a much wider range of abnormal conditions than the existing pump, including vapor/gas bubbles and increased pressure drop when employed to cool two suits simultaneously. A positive displacement, external gear type pump was selected because it offers the most compact and highest efficiency solution over the required range of flow rates and pressure drops. An additional benefit of selecting a gear pump design is that it is self priming and capable of ingesting non-condensable gas without becoming air locked. The chosen pump design consists of a 28 V DC, brushless, seal-less, permanent magnet motor driven, external gear pump that utilizes a Honeywell development that eliminates the need for magnetic coupling. The pump design was based on existing Honeywell designs, but incorporated features specifically for the PLSS application, including all of the key features of the flight pump. Testing at TEES verified that the pump meets the design requirements for range of flow rates, pressure drop, power consumption, working fluid temperature, operating time, gas ingestion, and restart capability under both ambient and vacuum conditions. The pump operated at 40 to 240 lbm/hr flow rate, 35 to 100 oF pump temperature, and 5 to 10 psid pressure rise. Power consumption of the pump controller at the nominal operating point in both ambient and vacuum conditions was 9.5 W, which was less than the 12 W predicted. Gas ingestion capabilities were tested by injecting 100 cc of air into the fluid line; the pump operated normally throughout this test.

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.

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.

Academic and Non-Academic Variables Related to Persistence, Transfer, and Attrition of Engineering Students.

ERIC Educational Resources Information Center

Van Erdewyk, Zeno Martin

Identified were characteristics of students who persisted in engineering, transferred to another major, or dropped out of college. Four hundred-thirty freshmen, sophomores, and juniors in the College of Engineering at the University of North Dakota were involved in the study during 1965-66. Data on students included American College Test scores,…

77 FR 37477 - Federal Motor Vehicle Safety Standards; Glazing Materials

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-21

... 4. Half Pound Ball Drop--Tempered Glass 5. Fracture Test 6. Shot Bag and Dart Drop Tests 7. Half... Rapporteurs) that assist WP.29 in researching, analyzing and developing technical regulations. One of the GRs... proposal concerning markings for GTRs in general, at the one-hundred-and- fortieth session of WP.29 in...

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...

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.

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.

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.

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.

Insights from the pollination drop proteome and the ovule transcriptome of Cephalotaxus at the time of pollination drop production.

PubMed

Pirone-Davies, Cary; Prior, Natalie; von Aderkas, Patrick; Smith, Derek; Hardie, Darryl; Friedman, William E; Mathews, Sarah

2016-05-01

Many gymnosperms produce an ovular secretion, the pollination drop, during reproduction. The drops serve as a landing site for pollen, but also contain a suite of ions and organic compounds, including proteins, that suggests diverse roles for the drop during pollination. Proteins in the drops of species of Chamaecyparis, Juniperus, Taxus, Pseudotsuga, Ephedra and Welwitschia are thought to function in the conversion of sugars, defence against pathogens, and pollen growth and development. To better understand gymnosperm pollination biology, the pollination drop proteomes of pollination drops from two species of Cephalotaxus have been characterized and an ovular transcriptome for C. sinensis has been assembled. Mass spectrometry was used to identify proteins in the pollination drops of Cephalotaxus sinensis and C. koreana RNA-sequencing (RNA-Seq) was employed to assemble a transcriptome and identify transcripts present in the ovules of C. sinensis at the time of pollination drop production. About 30 proteins were detected in the pollination drops of both species. Many of these have been detected in the drops of other gymnosperms and probably function in defence, polysaccharide metabolism and pollen tube growth. Other proteins appear to be unique to Cephalotaxus, and their putative functions include starch and callose degradation, among others. Together, the proteins appear either to have been secreted into the drop or to occur there due to breakdown of ovular cells during drop production. Ovular transcripts represent a wide range of gene ontology categories, and some may be involved in drop formation, ovule development and pollen-ovule interactions. The proteome of Cephalotaxus pollination drops shares a number of components with those of other conifers and gnetophytes, including proteins for defence such as chitinases and for carbohydrate modification such as β-galactosidase. Proteins likely to be of intracellular origin, however, form a larger component of drops from Cephalotaxus than expected from studies of other conifers. This is consistent with the observation of nucellar breakdown during drop formation in Cephalotaxus The transcriptome data provide a framework for understanding multiple metabolic processes that occur within the ovule and the pollination drop just before fertilization. They reveal the deep conservation of WUSCHEL expression in ovules and raise questions about whether any of the S-locus transcripts in Cephalotaxus ovules might be involved in pollen-ovule recognition. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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.

Calculation of Water Drop Trajectories to and About Arbitrary Three-Dimensional Bodies in Potential Airflow

NASA Technical Reports Server (NTRS)

Norment, H. G.

1980-01-01

Calculations can be performed for any atmospheric conditions and for all water drop sizes, from the smallest cloud droplet to large raindrops. Any subsonic, external, non-lifting flow can be accommodated; flow into, but not through, inlets also can be simulated. Experimental water drop drag relations are used in the water drop equations of motion and effects of gravity settling are included. Seven codes are described: (1) a code used to debug and plot body surface description data; (2) a code that processes the body surface data to yield the potential flow field; (3) a code that computes flow velocities at arrays of points in space; (4) a code that computes water drop trajectories from an array of points in space; (5) a code that computes water drop trajectories and fluxes to arbitrary target points; (6) a code that computes water drop trajectories tangent to the body; and (7) a code that produces stereo pair plots which include both the body and trajectories. Code descriptions include operating instructions, card inputs and printouts for example problems, and listing of the FORTRAN codes. Accuracy of the calculations is discussed, and trajectory calculation results are compared with prior calculations and with experimental data.

Impact of virus strain characteristics on early detection of highly pathogenic avian influenza infection in commercial table-egg layer flocks and implications for outbreak control.

PubMed

Weaver, J Todd; Malladi, Sasidhar; Goldsmith, Timothy J; Hueston, Will; Hennessey, Morgan; Lee, Brendan; Voss, Shauna; Funk, Janel; Der, Christina; Bjork, Kathe E; Clouse, Timothy L; Halvorson, David A

2012-12-01

Early detection of highly pathogenic avian influenza (HPAI) infection in commercial poultry flocks is a critical component of outbreak control. Reducing the time to detect HPAI infection can reduce the risk of disease transmission to other flocks. The timeliness of different types of detection triggers could be dependent on clinical signs that are first observed in a flock, signs that might vary due to HPAI virus strain characteristics. We developed a stochastic disease transmission model to evaluate how transmission characteristics of various HPAI strains might effect the relative importance of increased mortality, drop in egg production, or daily real-time reverse transcriptase (RRT)-PCR testing, toward detecting HPAI infection in a commercial table-egg layer flock. On average, daily RRT-PCR testing resulted in the shortest time to detection (from 3.5 to 6.1 days) depending on the HPAI virus strain and was less variable over a range of transmission parameters compared with other triggers evaluated. Our results indicate that a trigger to detect a drop in egg production would be useful for HPAI virus strains with long infectious periods (6-8 days) and including an egg-drop detection trigger in emergency response plans would lead to earlier and consistent reporting in some cases. We discuss implications for outbreak control and risk of HPAI spread attributed to different HPAI strain characteristics where an increase in mortality or a drop in egg production or both would be among the first clinical signs observed in an infected flock.

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.

Characterization of microporous separators for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Venugopal, Ganesh; Moore, John; Howard, Jason; Pendalwar, Shekhar

Several properties including porosity, pore-size distribution, thickness value, electrochemical stability and mechanical properties have to be optimized before a membrane can qualify as a separator for a lithium-ion battery. In this paper we present results of characterization studies carried out on some commercially available lithium-ion battery separators. The relevance of these results to battery performance and safety are also discussed. Porosity values were measured using a simple liquid absorption test and gas permeabilities were measured using a novel pressure drop technique that is similar in principle to the Gurley test. For separators from one particular manufacturer, the trend observed in the pressure drop times was found to be in agreement with the Gurley numbers reported by the separator manufacturer. Shutdown characteristics of the separators were studied by measuring the impedance of batteries containing the separators as a function of temperature. Overcharge tests were also performed to confirm that separator shutdown is indeed a useful mechanism for preventing thermal runaway situations. Polyethylene containing separators, in particular trilayer laminates of polypropylene, polyethylene and polypropylene, appear to have the most attractive properties for preventing thermal runaway in lithium ion cells.

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.

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.

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...

Cooling and solidification of liquid-metal drops in a gaseous atmosphere

NASA Technical Reports Server (NTRS)

Mccoy, J. K.; Markworth, A. J.; Collings, E. W.; Brodkey, R. S.

1992-01-01

The free fall of a liquid-metal drop, heat transfer from the drop to its environment, and solidification of the drop are described for both gaseous and vacuum atmospheres. A simple model, in which the drop is assumed to fall rectilinearly, with behavior like that of a rigid particle, is developed to describe cooling behavior. Recalescence of supercooled drops is assumed to occur instantaneously when a specified temperature is passed. The effects of solidification and experimental parameters on drop cooling are calculated and discussed. Major results include temperature as a function of time, and of drag, time to complete solidification, and drag as a function of the fraction of the drop solidified.

Multiple Off-Ice Performance Variables Predict On-Ice Skating Performance in Male and Female Division III Ice Hockey Players

PubMed Central

Janot, Jeffrey M.; Beltz, Nicholas M.; Dalleck, Lance D.

2015-01-01

The purpose of this study was to determine if off-ice performance variables could predict on-ice skating performance in Division III collegiate hockey players. Both men (n = 15) and women (n = 11) hockey players (age = 20.5 ± 1.4 years) participated in the study. The skating tests were agility cornering S-turn, 6.10 m acceleration, 44.80 m speed, modified repeat skate, and 15.20 m full speed. Off-ice variables assessed were years of playing experience, height, weight and percent body fat and off-ice performance variables included vertical jump (VJ), 40-yd dash (36.58m), 1-RM squat, pro-agility, Wingate peak power and peak power percentage drop (% drop), and 1.5 mile (2.4km) run. Results indicated that 40-yd dash (36.58m), VJ, 1.5 mile (2.4km) run, and % drop were significant predictors of skating performance for repeat skate (slowest, fastest, and average time) and 44.80 m speed time, respectively. Four predictive equations were derived from multiple regression analyses: 1) slowest repeat skate time = 2.362 + (1.68 x 40-yd dash time) + (0.005 x 1.5 mile run), 2) fastest repeat skate time = 9.762 - (0.089 x VJ) - (0.998 x 40-yd dash time), 3) average repeat skate time = 7.770 + (1.041 x 40-yd dash time) - (0.63 x VJ) + (0.003 x 1.5 mile time), and 4) 47.85 m speed test = 7.707 - (0.050 x VJ) - (0.01 x % drop). It was concluded that selected off-ice tests could be used to predict on-ice performance regarding speed and recovery ability in Division III male and female hockey players. Key points The 40-yd dash (36.58m) and vertical jump tests are significant predictors of on-ice skating performance specific to speed. In addition to 40-yd dash and vertical jump, the 1.5 mile (2.4km) run for time and percent power drop from the Wingate anaerobic power test were also significant predictors of skating performance that incorporates the aspect of recovery from skating activity. Due to the specificity of selected off-ice variables as predictors of on-ice performance, coaches can elect to assess player performance off-ice and focus on other uses of valuable ice time for their individual teams. PMID:26336338

Variation of rain intensity and drop size distribution with General Weather Patterns (GWL)

NASA Astrophysics Data System (ADS)

Ghada, Wael; Buras, Allan; Lüpke, Marvin; Menzel, Annette

2017-04-01

Short-duration rainfall extremes may cause flash floods in certain catchments (e.g. cities or fast responding watersheds) and pose a great risk to affected communities. In order to predict their occurrence under future climate change scenarios, their link to atmospheric circulation patterns needs to be well understood. We used a comprehensive data set of meteorological data (temperature, rain gauge precipitation) and precipitation spectra measured by a disdrometer (OTT PARSIVEL) between October 2008 and June 2010 at Freising, southern Germany. For the 21 months of the study period, we integrated the disdrometer spectra over intervals of 10 minutes to correspond to the temporal resolution of the weather station data and discarded measurements with air temperatures below 0°C. Daily General Weather Patterns ("Großwetterlagen", GWL) were downloaded from the website of the German Meteorological Service. Out of the 29 GWL, 14 were included in the analysis for which we had at least 12 rain events during our study period. For the definition of a rain event, we tested different lengths of minimum inter-event times and chose 30 min as a good compromise between number and length of resulting events; rain events started when more than 0.001 mm/h (sensitivity of the disdrometer) were recorded. The length of the rain events ranged between 10 min and 28 h (median 130 min) with the maximum rain intensity recorded being 134 mm/h on 24-07-2009. Seasonal differences were identified for rain event average intensities and maximum intensities per event. The influence of GWL on rain properties such as rain intensity and drop size distribution per time step and per event was investigated based on the above mentioned rain event definition. Pairwise Wilcoxon-tests revealed that higher rain intensity and larger drops were associated with the GWL "Low over the British Isles" (TB), whereas low rain intensities and less drops per interval were associated with the GWL "High over Central Europe" (HM). "Trough over Central Europe" (TRM) was linked to smaller drops and "High Scandinavia-Iceland, Trough C. Europe" (HNFZ) had fewer drops per time step when compared to other GWL types. We also investigated the intra-event behavior regarding fluctuations in rain intensity, rain drop counts, and drop size distribution with time. When combined with predictions of circulation patterns, our analysis provides a detailed insight into the characteristics of rain events under different future climate scenarios, but definitively an extended measurement period and more measurement locations are needed for validation.

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.

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…

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…

[Effect of anti-inflammatory therapy on the treatment of dry eye syndrome].

PubMed

Mrukwa-Kominek, Ewa; Rogowska-Godela, Anna; Gierek-Ciaciura, Stanisława

2007-01-01

Dry eye syndrome is a common chronic disease; agents and strategies for its effective management are still lacking. The syndrome tends to be accompanied by ocular surface inflammation; therefore, the use of anti-inflammatory agents might prove beneficial. The authors present up-to-date guidelines, strategies, and efficacy of dry eye syndrome management, including anti-inflammatory treatment. As no diagnostic tests are now available to assess ocular surface inflammation severity, the right timing to launch an anti-inflammatory agent is difficult to determine. Patients with mild intermittent bouts of symptoms which can be alleviated with ophthalmic lubricants do not typically require anti-inflammatory therapy. The latter should be considered in those who do not respond to lubricating drops, obtain poor results on clinical tests, and show symptoms of ocular surface irritation (eg. conjunctivae redness). Anti-inflammatory treatment of dry eye syndrome may include short-term corticosteroids, cyclosporine A emulsion, oral tetracycline therapy, oral omega-3 fatty acid supplements, and autologous serum eye drops. Anti-inflammatory treatment should be safe and effective; potential benefits should be evaluated for each individual patient. The authors have reviewed the advantages of anti-inflammatory treatment in dry eye syndrome, presented in literature.

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

77 FR 69620 - Proposed Information Collection Request; Comment Request; Renewable Fuels Standard (RFS2) Program

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-20

.../intend to own RINs which include blenders, brokers and marketers dropped significantly. Importers dropped... marketers dropped from 3000 responses to 1650 thus lessoning the reporting burden. The number of responses...

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.

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.

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

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.

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

A theoretical and experimental study of turbulent evaporating sprays

NASA Technical Reports Server (NTRS)

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

1984-01-01

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

Electrowetting-driven spreading and jumping of drops in oil

NASA Astrophysics Data System (ADS)

Hong, Jiwoo; Lee, Sang Joon

2013-11-01

Electrowetting-based practical applications include digital microfluidics, liquid lenses, and reflective displays. Most of them are performed in water/oil system, because oil medium reduces the contact-angle hysteresis and prevents drop evaporation. In this study, the effects of drop volume, oil viscosity, and applied voltage on the dynamic behaviors of spreading drops, such as transition of spreading pattern and response time, are investigated. Interestingly, jumping phenomena of drops are observed in oil when the applied voltage is turned off after reaching the electrowetted equilibrium radius of drops. A numerical model to predict the transient behavior of jumping drops is formulated based on the phase-field method. The numerical results for the transient deformation of jumping drops show quantitative agreement with the experimental results.

North American XF-82 Twin Mustang Prepares for Ramjet Test Flight

NASA Image and Video Library

1949-04-21

Pilot William Swann, right cockpit, prepares the North American XF-82 Twin Mustang for flight at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The aircraft was one of only two prototypes built by North American in October 1945 and powered by Packard Merlin V-1650 piston engines. Over 270 of the F-82 long-distance pursuit fighters were produced during the 1940s. The Mustang’s unique two-pilot configuration allowed one pilot to rest during the long missions and thus be ready for action upon arrival. The NACA took possession of this XF-82 in October 1947. NACA Lewis used the XF-82 as a test bed for ramjet flight tests. Ramjets are continually burning tubes that use the compressed atmospheric air to produce thrust. Ramjets are extremely efficient at high speeds, but rely on some sort of booster to attain that high speed. NACA Lewis undertook an extensive ramjet program in the 1940s that included combustion studies in the Altitude Wind Tunnel, a number of flight tests, and missile drops from aircraft. The 16-inch diameter ramjet missile was fixed to the XF-82 Mustang’s wing and dropped from high altitudes off of Wallops Island. The tests determined the ramjet’s performance and operational characteristics in the transonic range.

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.

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

Application of a Novel DCPD Adjustment Method for the J-R Curve Characterization: A study based on ORNL and ASTM Interlaboratory Results

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

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

Material fracture toughness in the fully ductile region can be described by a J-integral vs. crack growth resistance curve (J-R curve). As a conventional J-R curve measurement method, the elastic unloading compliance (EUC) method becomes impractical for elevated temperature testing due to relaxation of the material and friction induced back-up shape of the J-R curve. One alternative solution of J-R curve testing applies the Direct Current Potential Drop (DCPD) technique for measuring crack extension. However, besides crack growth, potential drop can also be influenced by plastic deformation, crack tip blunting, etc., and uncertainties exist in the current DCPD methodology especiallymore » in differentiating potential drop due to stable crack growth and due to material deformation. Thus, using DCPD for J-R curve determination remains a challenging task. In this study, a new adjustment procedure for applying DCPD to derive the J-R curve has been developed for conventional fracture toughness specimens, including compact tension, three-point bend, and disk-shaped compact specimens. Data analysis has been performed on Oak Ridge National Laboratory (ORNL) and American Society for Testing and Materials (ASTM) interlaboratory results covering different specimen thicknesses, test temperatures, and materials, to evaluate the applicability of the new DCPD adjustment procedure for J-R curve characterization. After applying the newly-developed procedure, direct comparison between the DCPD method and the normalization method on the same specimens indicated close agreement for the overall J-R curves, as well as the provisional values of fracture toughness near the onset of ductile crack extension, Jq, and of tearing modulus.« less

Linking women who test HIV-positive in pregnancy-related services to long-term HIV care and treatment services: a systematic review.

PubMed

Ferguson, Laura; Grant, Alison D; Watson-Jones, Deborah; Kahawita, Tanya; Ong'ech, John O; Ross, David A

2012-05-01

To quantify attrition between women testing HIV-positive in pregnancy-related services and accessing long-term HIV care and treatment services in low- or middle-income countries and to explore the reasons underlying client drop-out by synthesising current literature on this topic. A systematic search in Medline, EMBASE, Global Health and the International Bibliography of the Social Sciences of literature published 2000-2010. Only studies meeting pre-defined quality criteria were included. Of 2543 articles retrieved, 20 met the inclusion criteria. Sixteen (80%) drew on data from sub-Saharan Africa. The pathway between testing HIV-positive in pregnancy-related services and accessing long-term HIV-related services is complex, and attrition was usually high. There was a failure to initiate highly active antiretroviral therapy (HAART) among 38-88% of known-eligible women. Providing 'family-focused care', and integrating CD4 testing and HAART provision into prevention of mother-to-child HIV transmission services appear promising for increasing women's uptake of HIV-related services. Individual-level factors that need to be addressed include financial constraints and fear of stigma. Too few women negotiate the many steps between testing HIV-positive in pregnancy-related services and accessing HIV-related services for themselves. Recent efforts to stem patient drop-out, such as the MTCT-Plus Initiative, hold promise. Addressing barriers and enabling factors both within health facilities and at the levels of the individual woman, her family and society will be essential to improve the uptake of services. © 2012 Blackwell Publishing Ltd.

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.

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

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.

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.

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.

SHERPA Electromechanical Test Bed

NASA Technical Reports Server (NTRS)

Wason, John D.

2005-01-01

SHERPA (Strap-on High-altitude Entry Reconnaissance and Precision Aeromaneuver system) is a concept for low-cost-high-accuracy Martian reentry guidance for small scout-class missions with a capsule diameter of approximately 1 meter. This system uses moving masses to change the center of gravity of the capsule in order to control the lift generated by the controlled imbalance. This project involved designing a small proof-of-concept demonstration system that can be used to test the concept through bench-top testing, hardware-in-the-loop testing, and eventually through a drop test from a helicopter. This project has focused on the Mechatronic design aspects of the system including the mechanical, electrical, computer, and low-level control of the concept demonstration system.

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.

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

Analysis of cryogenic propellant behavior in microgravity and low thrust environments

NASA Technical Reports Server (NTRS)

Fisher, Mark F.; Schmidt, George R.; Martin, James J.

1991-01-01

Predictions of a CFD program calculating a fluid-free surface shape and motion as a function of imposed acceleration are validated against the drop-tower test data collected to support design and performance assessments of the Saturn S-IVB stage liquid-hydrogen tank. The drop-tower facility, experimental package, and experiment procedures are outlined, and the program is described. It is noted that the validation analysis confirms the program's suitability for predicting low-g fluid slosh behavior, and that a similar analysis could examine the effect of incorporating baffles and screens to impede initiation of any unwanted side loads due to slosh. It is concluded that in actual vehicle applications, the engine thrust tailoff profile should be included in computer simulations if the precise interface versus time definition is needed.

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.

A Fast and Easily-Realized Concentration Sensor for Binary Gas Mixtures and Its Design Analysis.

PubMed

Guan, Yu; Lu, Song; Zhang, Dan; Hu, Yang; Yuan, Wei

2018-04-19

A low-cost and easily-realized sensing device used for the detection of gas mixtures at different concentrations is presented. Its sensing part includes a small critical nozzle, a laminar structure, and a differential pressure sensor. When gas flows through the laminar structure, there is a pressure drop between both ends of it, and for different components of gas, the pressure drop is different. Based on this feature, the concentration detection is achieved. Concentration tests for two types of fire extinguishing agents CBrF₃ and C₃HF₇ are presented. The results show the characteristics of fast response/recovery time, high accuracy, and good repeatability. Based on the theoretical analysis, the effects of the design parameters on the sensing performance to concentration detection are discussed in detail.

Interaction of a liquid jet with an oncoming gas stream

NASA Astrophysics Data System (ADS)

Koval', M. A.; Shvets, A. I.

1987-06-01

Wind-tunnel tests were carried out to study the interaction between water jets issuing from various types of nozzles (including cylindrical) and subsonic and supersonic air streams with Mach numbers from 0.3 to 3 and Reynolds numbers from 1 x 10 to the 6th to 3 x 10 to the 7th. The following interaction structure was observed: (1) at moderate outflow velocities, the liquid jet has an extended region, which subsequently expands abruptly as a spherical or mushroom-shaped drop; (2) this drop is atomized in the peripheral region and is carried away as a gas-liquid mixture; (3) a shock wave is formed in front of the jet in the oncoming supersonic stream; and (4) a separated flow region is present in the vicinity of the cylindrical nozzle section.

Rectangular Drop Vehicle in the Zero Gravity Research Facility

NASA Image and Video Library

1969-03-21

A rectangular drop test vehicle perched above 450-foot shaft at the Zero Gravity Research Facility at NASA Lewis Research Center. The drop tower was designed to provide five seconds of microgravity during a normal drop, but had a pneumatic gun that could quickly propel the vehicle to the top of the shaft prior to its drop, thus providing ten seconds of microgravity. The shaft contained a steel-lined vacuum chamber 20 feet in diameter and 469 feet deep. The package was stopped at the bottom of the pit by a 15-foot deep deceleration cart filled with polystyrene pellets. 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 ten second drops. After the test vehicle was prepared it was suspended above the shaft from the top of the chamber. A lid was used to seal the top of the chamber. The vacuum system reduced the pressure levels inside the chamber. The bolt holding the vehicle was then sheared and the vehicle plummeted into the deceleration cart.

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

Simple, robust storage of drops and fluids in a microfluidic device.

PubMed

Boukellal, Hakim; Selimović, Seila; Jia, Yanwei; Cristobal, Galder; Fraden, Seth

2009-01-21

We describe a single microfluidic device and two methods for the passive storage of aqueous drops in a continuous stream of oil without any external control but hydrodynamic flow. Advantages of this device are that it is simple to manufacture, robust under operation, and drops never come into contact with each other, making it unnecessary to stabilize drops against coalescence. In one method the device can be used to store drops that are created upstream from the storage zone. In the second method the same device can be used to simultaneously create and store drops from a single large continuous fluid stream without resorting to the usual flow focusing or T-junction drop generation processes. Additionally, this device stores all the fluid introduced, including the first amount, with zero waste. Transport of drops in this device depends, however, on whether or not the aqueous drops wet the device walls. Analysis of drop transport in these two cases is presented. Finally, a method for extraction of the drops from the device is also presented, which works best when drops do not wet the walls of the chip.

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.

Relationship of starch changes to puffing expansion of parboiled rice.

PubMed

Mahanta, Charu Lata; Bhattacharya, K R

2010-03-01

'Intan' variety of paddy (Oryza sativa) was tested for puffing. It was parboiled under a wide range of paddy moisture content, steaming pressure and time, as also temperature and time of sand heating. The resulting milled rices were studied for their diverse properties including puffing. Indices of starch changes in the samples were calculated as: (1) gelatinisation index from the solubility of amylose in 0.2 N KOH; (2) amylopectin retrogradation from the post-production drop in room-temperature hydration power of the parboiled paddy during air-drying, (3) thermal breakdown of starch from the drop in gel permeation chromatographic fraction I of starch; lipid-amylose complexation indirectly from (4) drop in rate of water uptake during cooking and (5) cooked-rice firmness. It was found that the puffing expansion was very highly correlated with the combined above 5 indices of starch changes, as much as 90% of the variation in puffing being explainable on that basis. Puffing was promoted by gelatinisation as well as lipid-amylose complexation, but was retarded by amylopectin retrogradation and probably starch breakdown.

Behavior of sulfur mustard in sand, concrete, and asphalt matrices: Evaporation, degradation, and decontamination.

PubMed

Jung, Hyunsook; Choi, Seungki

2017-10-15

The evaporation, degradation, and decontamination of sulfur mustard on environmental matrices including sand, concrete, and asphalt are described. A specially designed wind tunnel and thermal desorber in combination with gas chromatograph (GC) produced profiles of vapor concentration obtained from samples of the chemical agent deposited as a drop on the surfaces of the matrices. The matrices were exposed to the chemical agent at room temperature, and the degradation reactions were monitored and characterized. A vapor emission test was also performed after a decontamination process. The results showed that on sand, the drop of agent spread laterally while evaporating. On concrete, the drop of the agent was absorbed immediately into the matrix while spreading and evaporating. However, the asphalt surface conserved the agent and slowly released parts of the agent over an extended period of time. The degradation reactions of the agent followed pseudo first order behavior on the matrices. Trace amounts of the residual agent present at the surface were also released as vapor after decontamination, posing a threat to the exposed individual and environment.

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

NASA Astrophysics Data System (ADS)

Liu, Yanxiong; Liaw, Benjamin

2010-02-01

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

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.

Specialized neuromuscular training to improve neuromuscular function and biomechanics in a patient with quiescent juvenile rheumatoid arthritis.

PubMed

Myer, Gregory D; Brunner, Hermine I; Melson, Paula G; Paterno, Mark V; Ford, Kevin R; Hewett, Timothy E

2005-08-01

The purpose of this case report is to describe a novel multidisciplinary approach for evaluating and preparing a patient with quiescent juvenile rheumatoid arthritis (JRA) for safe sports participation. The patient was a 10-year-old girl with a history of bilateral knee arthritis who desired to participate in soccer and basketball. Range of motion and manual muscle testing of the lower extremity were within normal limits. Neuromuscular testing included kinematic and kinetic testing, isokinetic assessment, and postural stability testing. The patient's gait was near normal; however, she had narrowed step width and increased knee flexion at heel-strike. Landing analysis during a box drop vertical jump task showed increased and imbalanced (right versus left lower extremity) peak impact forces. The testing was followed by specialized neuromuscular training (SNT). Following SNT, heel-strike and step width were within normal limits, peak impact forces on the box drop test decreased by 31%, imbalance decreased by 46%, and vertical jump increased 15%. The isokinetic strength ratio between knee flexors and extensors and the overall balance measures were within normal limits and equal bilaterally. Patients with quiescent JRA may have abnormal biomechanics, which could place them at increased risk for injury or future articular cartilage damage. Specialized neuromuscular training may have helped to decrease the patient's risk for future injury or disease progression.

Bioinspired plate-based fog collectors.

PubMed

Heng, Xin; Luo, Cheng

2014-09-24

In a recent work, we explored the feeding mechanism of a shorebird to transport liquid drops by repeatedly opening and closing its beak. In this work, we apply the corresponding results to develop a new artificial fog collector. The collector includes two nonparallel plates. It has three advantages in comparison with existing artificial collectors: (i) easy fabrication, (ii) simple design to scale up, and (iii) active transport of condensed water drops. Two collectors have been built. A small one with dimensions of 4.2 × 2.1 × 0.05 cm(3) (length × width × thickness) was first built and tested to examine (i) the time evolution of condensed drop sizes and (ii) the collection processes and efficiencies on the glass, SiO2, and SU-8 plates. Under similar experimental conditions, the amount of water collected per unit area on the small collector is about 9.0, 4.7, and 3.7 times, respectively, as much as the ones reported for beetles, grasses, and metal wires, and the total amount of water collected is around 33, 18, and 15 times. On the basis of the understanding gained from the tests on the small collector, a large collector with dimensions of 26 × 10 × 0.2 cm(3) was further built and tested, which was capable of collecting 15.8 mL of water during a period of 36 min. The amount of water collected, when it is scaled from 36 to 120 min, is about 878, 479, or 405 times more than what was collected by individual beetles, grasses, or metal wires.

Space shuttle phase B wind tunnel model and test information. Volume 3: Launch configuration

NASA Technical Reports Server (NTRS)

Glynn, J. L.; Poucher, D. E.

1988-01-01

Archived wind tunnel test data are available for flyback booster or other alternate recoverable configuration as well as reusable orbiters studied during initial development (Phase B) of the Space Shuttle, including contractor data for an extensive variety of configurations with an array of wing and body planforms. The test data have been compiled into a database and are available for application to current winged flyback or recoverable booster aerodynamic studies. The Space Shuttle Phase B Wind Tunnel Database is structured by vehicle component and configuration. Basic components include booster, orbiter, and launch vehicle. Booster configuration types include straight and delta wings, canard, cylindrical, retroglide and twin body. Orbiter configurations include straight and delta wings, lifting body, drop tanks and double delta wings. Launch configurations include booster and orbiter components in various stacked and tandem combinations. The digital database consists of 220 files containing basic tunnel data. Database structure is documented in a series of reports which include configuration sketches for the various planforms tested. This is Volume 3 -- launch configurations.

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.

Behavior of fluids in a weightless environment

NASA Technical Reports Server (NTRS)

Fester, D. A.; Eberhardt, R. N.; Tegart, J. R.

1977-01-01

Fluid behavior in a low-g environment is controlled primarily by surface tension forces. Certain fluid and system characteristics determine the magnitude of these forces for both a free liquid surface and liquid in contact with a solid. These characteristics, including surface tension, wettability or contact angle, system geometry, and the relationships governing their interaction, are discussed. Various aspects of fluid behavior in a low-g environment are then presented. This includes the formation of static interface shapes, oscillation and rotation of drops, coalescence, the formation of foams, tendency for cavitation, and diffusion in liquids which were observed during the Skylab fluid mechanics science demonstrations. Liquid reorientation and capillary pumping to establish equilibrium configurations for various system geometries, observed during various free-fall (drop-tower) low-g tests, are also presented. Several passive low-g fluid storage and transfer systems are discussed. These systems use surface tension forces to control the liquid/vapor interface and provide gas-free liquid transfer and liquid-free vapor venting.

Two-phase pressure drop in a helical coil flow boiling system

NASA Astrophysics Data System (ADS)

Hardik, B. K.; Prabhu, S. V.

2018-05-01

The objective of the present work is to study the two-phase pressure drop in helical coils. Literature on the two-phase pressure drop in a helical coil suggests the complexity in flow boiling inside a helical coil due to secondary flow. Most of correlations reported in the literature on the two-phase pressure drop in a helical coil are limited to a specific operating range. No general correlation is available for a helical coil which is applicable for all fluids. In the present study, an experimental databank collected containing a total of 832 data points includes the data from the present study and from the literature. The data includes diabatic pressure drop of two fluids namely water and R123. Data covers a range of parameters namely a mass flux of 120-2058 kg/m2 s, a heat flux of 18-2831 kW/m2, an exit quality of 0.03-1, a density ratio of 32-1404 and a coil to tube diameter ratio of 14-58. The databank is compared with eighteen empirical correlations which include well referred correlations of straight tubes and the available correlations of helical coils. The straight tube correlations are not working well for the present data set. The helical coil correlations work reasonably well for the present databank. A correlation is suggested to predict the two-phase pressure drop in helical coils. The present study suggests that the influence of a helical coil is completely included in the single phase pressure drop correlation for helical coils.

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.

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.

Free-to-Roll Testing of Airplane Models in Wind Tunnels

NASA Technical Reports Server (NTRS)

Capone, Francis J.; Owens, D. Bruce; Hall, Robert M.

2007-01-01

A free-to-roll (FTR) test technique and test rig make it possible to evaluate both the transonic performance and the wingdrop/ rock behavior of a high-strength airplane model in a single wind-tunnel entry. The free-to-roll test technique is a single degree-of-motion method in which the model is free to roll about the longitudinal axis. The rolling motion is observed, recorded, and analyzed to gain insight into wing-drop/rock behavior. Wing-drop/rock is one of several phenomena symptomatic of abrupt wing stall. FTR testing was developed as part of the NASA/Navy Abrupt Wing Stall Program, which was established for the purposes of understanding and preventing significant unexpected and uncommanded (thus, highly undesirable) lateral-directional motions associated with wing-drop/rock, which have been observed mostly in fighter airplanes under high-subsonic and transonic maneuvering conditions. Before FTR testing became available, wingrock/ drop behavior of high-performance airplanes undergoing development was not recognized until flight testing. FTR testing is a reliable means of detecting, and evaluating design modifications for reducing or preventing, very complex abrupt wing stall phenomena in a ground facility prior to flight testing. The FTR test rig was designed to replace an older sting attachment butt, such that a model with its force balance and support sting could freely rotate about the longitudinal axis. The rig (see figure) includes a rotary head supported in a stationary head with a forward spherical roller bearing and an aft needle bearing. Rotation is amplified by a set of gears and measured by a shaft-angle resolver; the roll angle can be resolved to within 0.067 degrees at a rotational speed up to 1,000 degrees/s. An assembly of electrically actuated brakes between the rotary and stationary heads can be used to hold the model against a rolling torque at a commanded roll angle. When static testing is required, a locking bar is used to fix the rotating head rigidly to the stationary head. Switching between the static and FTR test modes takes only about 30 minutes. The FTR test rig was originally mounted in a 16-ft (approximately 4.0-m) transonic wind tunnel, but could just as well be adapted to use in any large wind tunnel. In one series of tests on the FTR rig, static and dynamic characteristics of models of four different fighter airplanes were measured. Two of the models exhibited uncommanded lateral motions; the other two did not. A figure of merit was developed to discern the severity of lateral motions. Using this figure of merit, it was shown that the FTR test technique enabled identification of conditions under which the uncommanded lateral motions occurred. The wind-tunnel conditions thus identified were found to be correlated with flight conditions under which the corresponding full-size airplanes exhibited uncommanded lateral motions.

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.

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

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)

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.

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.

Impact Delamination and Fracture in Aluminum/Acrylic Sandwich Plates

NASA Technical Reports Server (NTRS)

Liaw, Benjamin; Zeichner, Glenn; Liu, Yanxiong; Bowles, Kenneth J. (Technical Monitor)

2000-01-01

Impact-induced delamination and fracture in 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy were generated in an instrumented drop-weight impact machine. Although only a small dent was produced on the aluminum side when a hemispherical penetrator tup was dropped onto it from a couple of inches, a large ring of delamination at the interface was observed. The delamination damage was often accompanied by severe shattering in the acrylic substratum. Damage patterns in the acrylic layer include radial and ring cracks and, together with delamination at the interface, may cause peeling-off of acrylic material from the sandwich plate. Theory of stress-wave propagation can be used to explain these damage patterns. The impact tests were conducted at various temperatures. The results also show clearly that temperature effect is very important in impact damage. For pure cast acrylic nil-ductile transition (NDT) occurs between 185-195 F. Excessive impact energy was dissipated into fracture energy when tested at temperature below this range or through plastic deformation when tested at temperature above the NDT temperature. Results from this study will be used as baseline data for studying fiber-metal laminates, such as GLARE and ARALL for advanced aeronautical and astronautical applications.

Malfunction of medical equipment as a result of mains borne interference.

PubMed

Railton, R; Currie, G D; Corner, G A; Evans, A L

1993-08-01

Medical equipment has become more intelligent as the manufacturers have incorporated the latest microprocessor based technology. Equipment malfunction can be caused at any time by inherent errors in the control program but it is particularly important that this is designed to cope with the effects of electrical interference which, in addition, may cause corruption of the software. We have considered interference found in the mains supply in the hospital environment. Using a test protocol with appropriate interference simulators, a wide range of medical equipment was removed temporarily from use and its immunity to electrical mains borne interference tested. Battery operated mains rechargeable devices were unaffected by mains voltage variations including drop-outs and sags whereas mains powered devices were affected to varying degrees of severity. In particular, repetitive drop-outs caused loss of power due to fuse blowing in some life support equipment. Impulses affected 25% and pulse bursts 50% of the equipment tested with some evidence that the more recent designs coped better. The EEC Directive on electro-medical compatibility compliance may cause the design of equipment to be improved but hospitals will have to cope with the above problems in their existing equipment for many years to come.

Small-Scale Drop-Size Variability: Empirical Models for Drop-Size-Dependent Clustering in Clouds

NASA Technical Reports Server (NTRS)

Marshak, Alexander; Knyazikhin, Yuri; Larsen, Michael L.; Wiscombe, Warren J.

2005-01-01

By analyzing aircraft measurements of individual drop sizes in clouds, it has been shown in a companion paper that the probability of finding a drop of radius r at a linear scale l decreases as l(sup D(r)), where 0 less than or equals D(r) less than or equals 1. This paper shows striking examples of the spatial distribution of large cloud drops using models that simulate the observed power laws. In contrast to currently used models that assume homogeneity and a Poisson distribution of cloud drops, these models illustrate strong drop clustering, especially with larger drops. The degree of clustering is determined by the observed exponents D(r). The strong clustering of large drops arises naturally from the observed power-law statistics. This clustering has vital consequences for rain physics, including how fast rain can form. For radiative transfer theory, clustering of large drops enhances their impact on the cloud optical path. The clustering phenomenon also helps explain why remotely sensed cloud drop size is generally larger than that measured in situ.

Mechanical testing and finite element analysis of orthodontic teardrop loop.

PubMed

Coimbra, Maria Elisa Rodrigues; Penedo, Norman Duque; de Gouvêa, Jayme Pereira; Elias, Carlos Nelson; de Souza Araújo, Mônica Tirre; Coelho, Paulo Guilherme

2008-02-01

Understanding how teeth move in response to mechanical loads is an important aspect of orthodontic treatment. Treatment planning should include consideration of the appliances that will meet the desired loading of the teeth to result in optimized treatment outcomes. The purpose of this study was to evaluate the use of computer simulation to predict the force and the torsion obtained after the activation of tear drop loops of 3 heights. Seventy-five retraction loops were divided into 3 groups according to height (6, 7, and 8 mm). The loops were subjected to tensile load through displacements of 0.5, 1.0, 1.5, and 2.0 mm, and the resulting forces and torques were recorded. The loops were designed in AutoCAD software(2005; Autodesk Systems, Alpharetta, GA), and finite element analysis was performed with Ansys software(version 7.0; Swanson Analysis System, Canonsburg, PA). Statistical analysis of the mechanical experiment results was obtained by ANOVA and the Tukey post-hoc test (P < .01). The correlation test and the paired t test (P < .05) were used to compare the computer simulation with the mechanical experiment. The computer simulation accurately predicted the experimentally determined mechanical behavior of tear drop loops of different heights and should be considered an alternative for designing orthodontic appliances before treatment.

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.

Pressure Profiles in a Loop Heat Pipe Under Gravity Influence

NASA Technical Reports Server (NTRS)

Ku, Jentung

2015-01-01

During the operation of a loop heat pipe (LHP), the viscous flow induces pressure drops in various elements of the loop. The total pressure drop is equal to the sum of pressure drops in vapor grooves, vapor line, condenser, liquid line and primary wick, and is sustained by menisci at liquid and vapor interfaces on the outer surface of the primary wick in the evaporator. The menisci will curve naturally so that the resulting capillary pressure matches the total pressure drop. In ground testing, an additional gravitational pressure head may be present and must be included in the total pressure drop when LHP components are placed in a non-planar configuration. Under gravity-neutral and anti-gravity conditions, the fluid circulation in the LHP is driven solely by the capillary force. With gravity assist, however, the flow circulation can be driven by the combination of capillary and gravitational forces, or by the gravitational force alone. For a gravity-assist LHP at a given elevation between the horizontal condenser and evaporator, there exists a threshold heat load below which the LHP operation is gravity driven and above which the LHP operation is capillary force and gravity co-driven. The gravitational pressure head can have profound effects on the LHP operation, and such effects depend on the elevation, evaporator heat load, and condenser sink temperature. This paper presents a theoretical study on LHP operations under gravity neutral, anti-gravity, and gravity-assist modes using pressure diagrams to help understand the underlying physical processes. Effects of the condenser configuration on the gravitational pressure head and LHP operation are also discussed.

Pressure Profiles in a Loop Heat Pipe under Gravity Influence

NASA Technical Reports Server (NTRS)

Ku, Jentung

2015-01-01

During the operation of a loop heat pipe (LHP), the viscous flow induces pressure drops in various elements of the loop. The total pressure drop is equal to the sum of pressure drops in vapor grooves, vapor line, condenser, liquid line and primary wick, and is sustained by menisci at liquid and vapor interfaces on the outer surface of the primary wick in the evaporator. The menisci will curve naturally so that the resulting capillary pressure matches the total pressure drop. In ground testing, an additional gravitational pressure head may be present and must be included in the total pressure drop when LHP components are placed in a non-planar configuration. Under gravity-neutral and anti-gravity conditions, the fluid circulation in the LHP is driven solely by the capillary force. With gravity assist, however, the flow circulation can be driven by the combination of capillary and gravitational forces, or by the gravitational force alone. For a gravity-assist LHP at a given elevation between the horizontal condenser and evaporator, there exists a threshold heat load below which the LHP operation is gravity driven and above which the LHP operation is capillary force and gravity co-driven. The gravitational pressure head can have profound effects on the LHP operation, and such effects depend on the elevation, evaporator heat load, and condenser sink temperature. This paper presents a theoretical study on LHP operations under gravity-neutral, anti-gravity, and gravity-assist modes using pressure diagrams to help understand the underlying physical processes. Effects of the condenser configuration on the gravitational pressure head and LHP operation are also discussed.

Smoothed particle hydrodynamics method for evaporating multiphase flows.

PubMed

Yang, Xiufeng; Kong, Song-Charng

2017-09-01

The smoothed particle hydrodynamics (SPH) method has been increasingly used for simulating fluid flows; however, its ability to simulate evaporating flow requires significant improvements. This paper proposes an SPH method for evaporating multiphase flows. The present SPH method can simulate the heat and mass transfers across the liquid-gas interfaces. The conservation equations of mass, momentum, and energy were reformulated based on SPH, then were used to govern the fluid flow and heat transfer in both the liquid and gas phases. The continuity equation of the vapor species was employed to simulate the vapor mass fraction in the gas phase. The vapor mass fraction at the interface was predicted by the Clausius-Clapeyron correlation. An evaporation rate was derived to predict the mass transfer from the liquid phase to the gas phase at the interface. Because of the mass transfer across the liquid-gas interface, the mass of an SPH particle was allowed to change. Alternative particle splitting and merging techniques were developed to avoid large mass difference between SPH particles of the same phase. The proposed method was tested by simulating three problems, including the Stefan problem, evaporation of a static drop, and evaporation of a drop impacting a hot surface. For the Stefan problem, the SPH results of the evaporation rate at the interface agreed well with the analytical solution. For drop evaporation, the SPH result was compared with the result predicted by a level-set method from the literature. In the case of drop impact on a hot surface, the evolution of the shape of the drop, temperature, and vapor mass fraction were predicted.

Development flight tests of the Viking decelerator system.

NASA Technical Reports Server (NTRS)

Murrow, H. N.; Eckstrom, C. V.; Henke, D. W.

1973-01-01

Significant aspects of a low altitude flight test phase of the overall Viking decelerator system development are given. This test series included nine aircraft drop tests that were conducted at the Joint Parachute Test Facility, El Centro, California, between September 1971 and May 1972. The test technique and analytical planning method utilized to best simulate loading conditions in a low density environment are presented and some test results are shown to assess their adequacy. Performance effects relating to suspension line lengths of 1.7 D sub o with different canopy loadings are noted. System hardware developments are described, in particular the utilization of a fabric deployment mortar cover which remained attached to the parachute canopy. Finally, the contribution of this test series to the overall program is assessed.

Impact Testing and Simulation of Composite Airframe Structures

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Littell, Justin D.; Horta, Lucas G.; Annett, Martin S.; Fasanella, Edwin L.; Seal, Michael D., II

2014-01-01

Dynamic tests were performed at NASA Langley Research Center on composite airframe structural components of increasing complexity to evaluate their energy absorption behavior when subjected to impact loading. A second objective was to assess the capabilities of predicting the dynamic response of composite airframe structures, including damage initiation and progression, using a state-of-the-art nonlinear, explicit transient dynamic finite element code, LS-DYNA. The test specimens were extracted from a previously tested composite prototype fuselage section developed and manufactured by Sikorsky Aircraft Corporation under the US Army's Survivable Affordable Repairable Airframe Program (SARAP). Laminate characterization testing was conducted in tension and compression. In addition, dynamic impact tests were performed on several components, including I-beams, T-sections, and cruciform sections. Finally, tests were conducted on two full-scale components including a subfloor section and a framed fuselage section. These tests included a modal vibration and longitudinal impact test of the subfloor section and a quasi-static, modal vibration, and vertical drop test of the framed fuselage section. 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 instrumentation such as accelerometers and strain gages and from full-field photogrammetry.

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.

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.

25 CFR 542.3 - How do I comply with this part?

Code of Federal Regulations, 2010 CFR

2010-04-01

... provide for drop/count observations, inclusive of hard drop/count, soft drop/count and currency acceptor... observations would be unexpected, the hard count and soft count rooms may be entered simultaneously... should be included in the Agreed-Upon Procedures report transmitted to the Commission. (4) Report Format...

Summary of CPAS EDU Testing Analysis Results

NASA Technical Reports Server (NTRS)

Romero, Leah M.; Bledsoe, Kristin J.; Davidson, John.; Engert, Meagan E.; Fraire, Usbaldo, Jr.; Galaviz, Fernando S.; Galvin, Patrick J.; Ray, Eric S.; Varela, Jose

2015-01-01

The Orion program's Capsule Parachute Assembly System (CPAS) project is currently conducting its third generation of testing, the Engineering Development Unit (EDU) series. This series utilizes two test articles, a dart-shaped Parachute Compartment Drop Test Vehicle (PCDTV) and capsule-shaped Parachute Test Vehicle (PTV), both of which include a full size, flight-like parachute system and require a pallet delivery system for aircraft extraction. To date, 15 tests have been completed, including six with PCDTVs and nine with PTVs. Two of the PTV tests included the Forward Bay Cover (FBC) provided by Lockheed Martin. Advancements in modeling techniques applicable to parachute fly-out, vehicle rate of descent, torque, and load train, also occurred during the EDU testing series. An upgrade from a composite to an independent parachute simulation allowed parachute modeling at a higher level of fidelity than during previous generations. The complexity of separating the test vehicles from their pallet delivery systems necessitated the use the Automatic Dynamic Analysis of Mechanical Systems (ADAMS) simulator for modeling mated vehicle aircraft extraction and separation. This paper gives an overview of each EDU test and summarizes the development of CPAS analysis tools and techniques during EDU testing.

Comparison of nonwoven fiberglass and stainless steel microfiber media in aerosol coalescence filtration

NASA Astrophysics Data System (ADS)

Manzo, Gabriel

Coalescing filters are used to remove small liquid droplets from air streams. They have numerous industrial applications including dehumidification, cabin air filtration, compressed air filtration, metal working, CCV, and agriculture. In compressed air systems, oils used for lubrication of compressor parts can aerosolize into the main air stream causing potential contamination concerns for downstream applications. In many systems, humid air can present problems to sensitive equipment and sensors. As the humid air cools, small water drops condense and can disrupt components that need to be kept dry. Fibrous nonwoven filter media are commonly used to coalesce small drops into larger drops for easier removal. The coalescing performance of a medium is dependent upon several parameters including permeability, porosity, and wettability. In many coalescing filters, glass fibers are used. In this work, the properties of steel fiber media are measured to see how these properties compare to glass fiber media. Steel fiber media has different permeability, porosity and wettability to oil and water than fiber glass media. These differences can impact coalescence performance. The impact of these differences in properties on coalescence filtration performance was evaluated in a coalescence test apparatus. The overall coalescence performance of the steel and glass nonwoven fiber media are compared using a filtration efficiency and filtration index. In many cases, the stainless steel media performed comparably to fiber glass media with efficiencies near 90%. Since stainless steel media had lower pressure drops than fiber glass media, its filtration index values were significantly higher. Broader impact of this work is the use of stainless steel fiber media as an alternative to fiber glass media in applications where aerosol filtration is needed to protect the environment or sensitive equipment and sensors.

The 13th Aerospace Mechanisms Symposium

NASA Technical Reports Server (NTRS)

Bond, A. C.

1979-01-01

Technological areas covered include propulsion, motion compensation, instrument pointing and adjustment, centrifuge testing, bearing design, vehicle braking, and cargo handling. Devices for satellite, missile, and hypersonic-wind-tunnel applications; space shuttle mechanical and thermal protection systems; and techniques for building large space structures are described. In addition, a fluid drop injector device for a Spacelab experiment, a helical grip for cable cars, and applications of rare earth permanent magnets are discussed.

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.

Testing of a controller for a hybrid capillary pumped loop thermal control system

NASA Technical Reports Server (NTRS)

Schweickart, Russell; Ottenstein, Laura; Cullimore, Brent; Egan, Curtis; Wolf, Dave

1989-01-01

A controller for a series hybrid capillary pumped loop (CPL) system that requires no moving parts does not resrict fluid flow has been tested and has demonstrated improved performance characteristics over a plain CPL system and simple hybrid CPL systems. These include heat load sharing, phase separation, self-regulated flow control and distribution, all independent of most system pressure drop. In addition, the controlled system demonstrated a greater heat transport capability than the simple CPL system but without the large fluid inventory requirement of the hybrid systems. A description of the testing is presented along with data that show the advantages of the system.

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.

[Safety and efficacy of a new preservative-free levocabastine ophthalmic solution (Levofree®) using the conjunctival provocation test].

PubMed

Allaire, C; Siou-Mermet, R; Bassols, A

2012-09-01

To evaluate the safety and efficacy of preservative-free levocabastine 0.05 % ophthalmic solution compared to placebo (vehicle) and to preserved levocabastine 0.05 % ophthalmic suspension in the prevention of allergic conjunctivitis induced by a conjunctival provocation test. Ninety-two subjects (18-50 years) with a previous history of allergic conjunctivitis to pollen were randomised to receive either preservative-free levocabastine solution in one eye and preserved levocabastine suspension in the fellow eye (n=69), or preservative-free levocabastine in one eye and placebo in the fellow eye (n=23). One drop of each product was administered 10 minutes (visit 3) and 4 hours (visit 4) prior to the provocation test. The primary efficacy criterion was the sum of the itching and conjunctival hyperemia scores assessed at 3, 5 and 10 minutes after the provocation test. The safety evaluation included adverse events, visual acuity, intra-ocular pressure and study drug drop sensation. The efficacy of the preservative-free solution was significantly higher than that of placebo at all time points (P≤0.01) with one exception at visit 4 (3 minutes after the provocation test). It was significantly higher than that of the preserved suspension at visit 3, and equivalent at visit 4. The incidence of adverse events was lower with the preservative-free solution than with the preserved suspension. 94.2 % and 95.7 % subjects rated preservative-free levocabastine drop sensation as "good" or "very good" at visits 3 and 4 respectively, whereas these rates were 68.1 % and 63.8 % with preserved levocabastine. This difference between the two formulations was highly statistically significant (P<0.001). The efficacy of preservative-free levocabastine was superior to that of the placebo and of the preserved suspension at visit 3, at least as effective as the preserved suspension at visit 4, and better tolerated at each visit. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

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

NASA Technical Reports Server (NTRS)

Zhang, Neng-Li; Chao, David F.

2001-01-01

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

Oscillations of a deformed liquid drop in an acoustic field

NASA Astrophysics Data System (ADS)

Shi, Tao; Apfel, Robert E.

1995-07-01

The oscillations of an axially symmetric liquid drop in an acoustic standing wave field in air have been studied using the boundary integral method. The interaction between the drop oscillation and sound field has been included in this analysis. Our computations focus on the frequency shift of small-amplitude oscillations of an acoustically deformed drop typical of a drop levitated in air. In the presence or absence of gravity, the trend and the magnitude of the frequency shift have been given in terms of drop size, drop deformation, and the strength of the sound field. Our calculations are compared with experiments performed on the United States Microgravity Laboratory (USML-1) and with ground-based measurements, and are found to be in good agreement within the accuracy of the experimental data.

Simultaneous Estimation of Ofloxacin, Clotrimazole, and Lignocaine Hydrochloride in Their Combined Ear-Drop Formulation by Two Spectrophotometric Methods.

PubMed

Bodiwala, Kunjan; Shah, Shailesh; Patel, Yogini; Prajapati, Pintu; Marolia, Bhavin; Kalyankar, Gajanan

2017-01-01

Two sensitive, accurate, and precise spectrophotometric methods have been developed and validated for the simultaneous estimation of ofloxacin (OFX), clotrimazole (CLZ), and lignocaine hydrochloride (LGN) in their combined dosage form (ear drops) without prior separation. The derivative ratio spectra method (method 1) includes the measurement of OFX and CLZ at zero-crossing points (ZCPs) of each other obtained from the ratio derivative spectra using standard LGN as a divisor, whereas the measurement of LGN at the ZCP of CLZ is obtained from the ratio derivative spectra using standard OFX as a divisor. The double divisor-ratio derivative method (method 2) includes the measurement of each drug at its amplitude in the double divisor-ratio spectra obtained using a standard mixture of the other two drugs as the divisor. Both methods were found to be linear (correlation coefficients of >0.996) over the ranges of 3-15, 10-50, and 20-100 μg/mL for OFX, CLZ, and LGN, respectively; precise (RSD of <2%); and accurate (recovery of >98%) for the estimation of each drug. The developed methods were successfully applied for the estimation of these drugs in a marketed ear-drop formulation. Excipients and other ingredients did not interfere with the estimation of these drugs. Both methods were statistically compared using the t-test.

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.

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.

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

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

NASA Technical Reports Server (NTRS)

Ku, Jen-Tung; Hoang, Triem T.

1998-01-01

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

Higher Drop in Speed during a Repeated Sprint Test in Soccer Players Reporting Former Hamstring Strain Injury

PubMed Central

Røksund, Ola D.; Kristoffersen, Morten; Bogen, Bård E.; Wisnes, Alexander; Engeseth, Merete S.; Nilsen, Ann-Kristin; Iversen, Vegard V.; Mæland, Silje; Gundersen, Hilde

2017-01-01

Aim: Hamstring strain injury is common in soccer. The aim of this study was to evaluate the physical capacity of players who have and have not suffered from hamstring strain injury in a sample of semi-professional and professional Norwegian soccer players in order to evaluate characteristics and to identify possible indications of insufficient rehabilitation. Method: Seventy-five semi-professional and professional soccer players (19 ± 3 years) playing at the second and third level in the Norwegian league participated in the study. All players answered a questionnaire, including one question about hamstring strain injury (yes/no) during the previous 2 years. They also performed a 40 m maximal sprint test, a repeated sprint test (8 × 20 m), a countermovement jump, a maximal oxygen consumption (VO2max) test, strength tests and flexibility tests. Independent sample t-tests were used to evaluate differences in the physical capacity of the players who had suffered from hamstring strain injury and those who had not. Mixed between-within subject's analyses of variance was used to compare changes in speed during the repeated sprint test between groups. Results: Players who reported hamstring strain injury during the previous two years (16%) had a significantly higher drop in speed (0.07 vs. 0.02 s, p = 0.007) during the repeated sprint test, compared to players reporting no previous hamstring strain injury. In addition, there was a significant interaction (groups × time) (F = 3.22, p = 0.002), showing that speed in the two groups changed differently during the repeated sprint test. There were no significant differences in relations to age, weight, height, body fat, linear speed, countermovement jump height, leg strength, VO2max, or hamstring flexibility between the groups. Conclusion: Soccer players who reported hamstring strain injury during the previous 2 years showed significant higher drop in speed during the repeated sprint test compared to players with no hamstring strain injury. The maximal speed, leg strength, ability to produce maximal power, endurance capacity, and hamstring flexibility was similar for both groups. Thus, a repeated sprint test consisting of 8 × 20 m could be used as a field-based diagnostic tool to identify players in need of reconditioning programs to ensure complete post-injury rehabilitation. PMID:28190999

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.

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.

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.

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.

Application of damage tolerance methodology in certification of the Piaggio P-180 Avanti

NASA Technical Reports Server (NTRS)

Johnson, Jerry

1992-01-01

The Piaggio P-180 Avanti, a twin pusher-prop engine nine-passenger business aircraft was certified in 1990, to the requirements of FAR Part 23 and Associated Special Conditions for Composite Structure. Certification included the application of a damage tolerant methodology to the design of the composite forward wing and empennage (vertical fin, horizontal stabilizer, tailcone, and rudder) structure. This methodology included an extensive analytical evaluation coupled with sub-component and full-scale testing of the structure. The work from the Damage Tolerance Analysis Assessment was incorporated into the full-scale testing. Damage representing hazards such as dropped tools, ground equipment, handling, and runway debris, was applied to the test articles. Additional substantiation included allowing manufacturing discrepancies to exist unrepaired on the full-scale articles and simulated bondline failures in critical elements. The importance of full-scale testing in the critical environmental conditions and the application of critical damage are addressed. The implication of damage tolerance on static and fatigue testing is discussed. Good correlation between finite element solutions and experimental test data was observed.

Surface settling in partially filled containers upon step reduction in gravity

NASA Technical Reports Server (NTRS)

Weislogel, Marl M.; Ross, Howard D.

1990-01-01

A large literature exists concerning the equilibrium configurations of free liquid/gas surfaces in reduced gravity environments. Such conditions generally yield surfaces of constant curvature meeting the container wall at a particular (contact) angle. The time required to reach and stabilize about this configuration is less studied for the case of sudden changes in gravity level, e.g. from normal- to low-gravity, as can occur in many drop tower experiments. The particular interest here was to determine the total reorientation time for such surfaces in cylinders (mainly), as a function primarily of contact angle and kinematic viscosity, in order to aid in the development of drop tower experiment design. A large parametric range of tests were performed and, based on an accompanying scale analysis, the complete data set was correlated. The results of other investigations are included for comparison.

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.

On the rising motion of a drop in stratified fluids

NASA Astrophysics Data System (ADS)

Bayareh, M.; Doostmohammadi, A.; Dabiri, S.; Ardekani, A. M.

2013-10-01

The rising dynamics of a deformable drop in a linearly stratified fluid is numerically obtained using a finite-volume/front-tracking method. Our results show that the drag coefficient of a spherical drop in a stratified fluid enhances as C_{d,s}/C_{d,h}-1˜ Fr_d^{-2.86} for drop Froude numbers in the range of 4 < Frd < 16. The role of the deformability of the drop on the temporal evolution of the motion is investigated along with stratification and inertial effects. We also present the important role of stratification on the transient rising motion of the drop. It is shown that a drop can levitate in the presence of a vertical density gradient. The drop undergoes a fading oscillatory motion around its neutrally buoyant position except for high viscosity ratio drops where the oscillation occurs around a density level lighter than the neutral buoyancy level. In addition, a detailed characterization of the flow signature of a rising drop in a linearly stratified fluid including the buoyancy induced vortices and the resultant buoyant jet is presented.

Dynamics of Oscillating and Rotating Liquid Drop using Electrostatic Levitator

NASA Astrophysics Data System (ADS)

Matsumoto, Satoshi; Awazu, Shigeru; Abe, Yutaka; Watanabe, Tadashi; Nishinari, Katsuhiro; Yoda, Shinichi

2006-11-01

In order to understand the nonlinear behavior of liquid drop with oscillatory and/or rotational motions, an experimental study was performed. The electrostatic levitator was employed to achieve liquid drop formation on ground. A liquid drop with about 3 mm in diameter was levitated. The oscillation of mode n=2 along the vertical axis was induced by an external electrostatic force. The oscillatory motions were observed to clarify the nonlinearities of oscillatory behavior. A relationship between amplitude and frequency shift was made clear and the effect of frequency shift on amplitude agreed well with the theory. The frequency shift became larger with increasing the amplitude of oscillation. To confirm the nonlinear effects, we modeled the oscillation by employing the mass-spring-damper system included the nonlinear term. The result indicates that the large-amplitude oscillation includes the effect of nonlinear oscillation. The sound pressure was imposed to rotate the liquid drop along a vertical axis by using a pair of acoustic transducers. The drop transited to the two lobed shape due to centrifugal force when nondimensional angular velocity exceeded to 0.58.

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.

Thermal imaging of levitated fresh and salt water drops during laser irradiation

NASA Astrophysics Data System (ADS)

Brownell, Cody; Biggs, Harrison

2017-11-01

Simulation of high energy laser propagation and scattering in the maritime environment is problematic, due to the high likelihood of turbulence, fog, and rain or sea spray within the beam path. Considering large water drops (diameters of approximately 1-mm), such as those found in a light rain, an incident high energy laser will lead to rapid evaporation of the water drop as it traverses the beam path. In this work we present surface temperature measurements of a water drop obtained using a FLIR IR camera. The drop is acoustically levitated, and subject to a continuous wave laser with a wavelength of 1070-nm and a mean irradiance of approximately 800 W/cm2. These measurements show that the steady-state surface temperature of the drop is well below the saturation temperature, and for pure substances the equilibrium temperature decreases with decreasing drop volume similar to observations with smaller aqueous aerosols. Temperature non-uniformity within the drop is also assessed from statistics of the surface temperature fluctuations. Preliminary results from irradiated salt water drops show notably different behavior from fresh water drops, including temperature spikes as the drop volume decreases and occasional nucleate boiling. Acknowledge support from ONR #N00014-17-WX-00031.

Effectiveness of Autologous Serum Eye Drops Combined With Punctal Plugs for the Treatment of Sjögren Syndrome-Related Dry Eye.

PubMed

Liu, Ying; Hirayama, Masatoshi; Cui, Xin; Connell, Samuel; Kawakita, Tetsuya; Tsubota, Kazuo

2015-10-01

To evaluate the efficacy and safety of autologous serum (AS) eye drops combined with punctal plugs (PPs) in patients with Sjögren syndrome (SS)-related dry eye. A retrospective clinical study was performed in patients with dry eye caused by SS. We evaluated the Schirmer test value, tear breakup time (tBUT), and fluorescein and Rose Bengal (RB) staining scores at baseline, 3 months, 6 months, 1 year, and >1 year after treatment. The dry eye indexes were also evaluated in 2 subgroups, which determined by the using of PPs, including the AS + PP group and AS only group. A total of 56 eyes of 28 patients were investigated with a mean follow-up of 42.3 ± 26.1 months. After the application of AS eye drops, the Schirmer test showed no significant changes. The tBUT (2.7 ± 1.9 seconds) was significantly improved at each time point (3.9 ± 3.1, 4.5 ± 3.1, 3.7 ± 2.5, and 5.1 ± 4.0; P < 0.01), fluorescein staining (4.3 ± 2.8) was significantly improved at each time point (2.2 ± 2.2, 1.9 ± 1.9, 1.8 ± 1.6, and 1.8 ± 1.8; P < 0.01), and RB (2.6 ± 3.0) staining was significantly improved from 6-month treatment (1.5 ± 1.9, 1.9 ± 1.9, and 1.4 ± 1.8; P < 0.05, 0.01, and 0.01, respectively). When combined with PPs, the tBUT and RB staining scores were found to be significantly improved in the AS + PP group compared with those of the AS only group. Long-term application of AS eye drops was found to be an effective and apparently safe treatment for SS dry eye. Furthermore, PPs in combination with AS eye drops were considered to have an additive effect on SS dry eye.

Small Liquid Hydrogen Tank for Drop Tower Tests

NASA Image and Video Library

1964-11-21

A researcher fills a small container used to represent a liquid hydrogen tank in preparation for a microgravity test in the 2.2-Second Drop Tower at the National Aeronautics and Space Administration (NASA) Lewis Research Center. For over a decade, NASA Lewis endeavored to make liquid hydrogen a viable propellant. Hydrogen’s light weight and high energy made it very appealing for rocket propulsion. One of the unknowns at the time was the behavior of fluids in the microgravity of space. Rocket designers needed to know where the propellant would be inside the fuel tank in order to pump it to the engine. NASA Lewis utilized sounding rockets, research aircraft, and the 2.2 Second Drop Tower to study liquids in microgravity. The drop tower, originally built as a fuel distillation tower in 1948, descended into a steep ravine. By early 1961 the facility was converted into an eight-floor, 100-foot tower connected to a shop and laboratory space. Small glass tanks, like this one, were installed in experiment carts with cameras to film the liquid’s behavior during freefall. Thousands of drop tower tests in the early 1960s provided an increased understanding of low-gravity processes and phenomena. The tower only afforded a relatively short experiment time but was sufficient enough that the research could be expanded upon using longer duration freefalls on sounding rockets or aircraft. The results of the early experimental fluid studies verified predictions made by Lewis researchers that the total surface energy would be minimized in microgravity.

Study of Impact Damage in PVA-ECC Beam under Low-Velocity Impact Loading Using Piezoceramic Transducers and PVDF Thin-Film Transducers.

PubMed

Qi, Baoxin; Kong, Qingzhao; Qian, Hui; Patil, Devendra; Lim, Ing; Li, Mo; Liu, Dong; Song, Gangbing

2018-02-24

Compared to conventional concrete, polyvinyl alcohol fiber reinforced engineering cementitious composite (PVA-ECC) offers high-strength, ductility, formability, and excellent fatigue resistance. However, impact-induced structural damage is a major concern and has not been previously characterized in PVA-ECC structures. We investigate the damage of PVA-ECC beams under low-velocity impact loading. A series of ball-drop impact tests were performed at different drop weights and heights to simulate various impact energies. The impact results of PVA-ECC beams were compared with mortar beams. A combination of polyvinylidene fluoride (PVDF) thin-film sensors and piezoceramic-based smart aggregate were used for impact monitoring, which included impact initiation and crack evolution. Short-time Fourier transform (STFT) of the signal received by PVDF thin-film sensors was performed to identify impact events, while active-sensing approach was utilized to detect impact-induced crack evolution by the attenuation of a propagated guided wave. Wavelet packet-based energy analysis was performed to quantify failure development under repeated impact tests.

Study of Impact Damage in PVA-ECC Beam under Low-Velocity Impact Loading Using Piezoceramic Transducers and PVDF Thin-Film Transducers

PubMed Central

Qian, Hui; Li, Mo; Liu, Dong; Song, Gangbing

2018-01-01

Compared to conventional concrete, polyvinyl alcohol fiber reinforced engineering cementitious composite (PVA-ECC) offers high-strength, ductility, formability, and excellent fatigue resistance. However, impact-induced structural damage is a major concern and has not been previously characterized in PVA-ECC structures. We investigate the damage of PVA-ECC beams under low-velocity impact loading. A series of ball-drop impact tests were performed at different drop weights and heights to simulate various impact energies. The impact results of PVA-ECC beams were compared with mortar beams. A combination of polyvinylidene fluoride (PVDF) thin-film sensors and piezoceramic-based smart aggregate were used for impact monitoring, which included impact initiation and crack evolution. Short-time Fourier transform (STFT) of the signal received by PVDF thin-film sensors was performed to identify impact events, while active-sensing approach was utilized to detect impact-induced crack evolution by the attenuation of a propagated guided wave. Wavelet packet-based energy analysis was performed to quantify failure development under repeated impact tests. PMID:29495277

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.

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

Space shuttle phase B wind tunnel model and test information. Volume 2: Orbiter configuration

NASA Technical Reports Server (NTRS)

Glynn, J. L.; Poucher, D. E.

1988-01-01

Archived wind tunnel test data are available for flyback booster or other alternative recoverable configurations as well as reusable orbiters studied during initial development (Phase B) of the Space Shuttle. Considerable wind tunnel data was acquired by the competing contractors and the NASA centers for an extensive variety of configurations with an array of wing and body planforms. All contractor and NASA wind tunnel test data acquired in the Phase B development have been compiled into a data base and are available for applying to current winged flyback or recoverable booster aerodynamic studies. The Space Shuttle Phase B Wind Tunnel Data Base is structured by vehicle component and configuration type. Basic components include the booster, the orbiter, and the launch vehicle. Booster configuration types include straight and delta wings, canard, cylindrical, retro-glide and twin body. Orbiter configuration types include straight and delta wings, lifting body, drop tanks, and double delta wings. Launch configuration types include booster and orbiter components in various stacked and tandem combinations.

Asteroid Composite Tape

NASA Astrophysics Data System (ADS)

1998-07-01

This is a composite tape showing 10 short segments primarily about asteroids. The segments have short introductory slides, which include brief descriptions about the shots. The segments are: (1) Radar movie of asteroid 1620 Geographos; (2) Animation of the trajectories of Toutatis and Earth (3) Animation of a landing on Toutatis; (4) Simulated encounter of an asteroid with Earth, includes a simulated impact trajectory; (5) An animated overview of the Manrover vehicle; (6) The Near Earth Asteroid Tracking project, includes a photograph of USAF Station in Hawaii, and animation of Earth approaching 4179 Toutatis and the asteroid Gaspara; (7) live video of the anchor tests of the Champoleon anchoring apparatus; (8) a second live video of the Champoleon anchor tests showing anchoring spikes, and collision rings; (9) An animated segment with narration about the Stardust mission with sound, which describes the mission to fly close to a comet, and capture cometary material for return to Earth; (10) live video of the drop test of a Stardust replica from a hot air balloon; this includes sound but is not narrated.

Synchronization Dynamics of Coupled Chemical Oscillators

NASA Astrophysics Data System (ADS)

Tompkins, Nathan

The synchronization dynamics of complex networks have been extensively studied over the past few decades due to their ubiquity in the natural world. Prominent examples include cardiac rhythms, circadian rhythms, the flashing of fireflies, predator/prey population dynamics, mammalian gait, human applause, pendulum clocks, the electrical grid, and of the course the brain. Detailed experiments have been done to map the topology of many of these systems and significant advances have been made to describe the mathematics of these networks. Compared to these bodies of work relatively little has been done to directly test the role of topology in the synchronization dynamics of coupled oscillators. This Dissertation develops technology to examine the dynamics due to topology within networks of discrete oscillatory components. The oscillatory system used here consists of the photo-inhibitable Belousov-Zhabotinsky (BZ) reaction water-in-oil emulsion where the oscillatory drops are diffusively coupled to one another and the topology is defined by the geometry of the diffusive connections. Ring networks are created from a close-packed 2D array of drops using the Programmable Illumination Microscope (PIM) in order to test Turing's theory of morphogenesis directly. Further technology is developed to create custom planar networks of BZ drops in more complicated topologies which can be individually perturbed using illumination from the PIM. The work presented here establishes the validity of using the BZ emulsion system with a PIM to study the topology induced effects on the synchronization dynamics of coupled chemical oscillators, tests the successes and limitations of Turing's theory of morphogenesis, and develops new technology to further probe the effects of network topology on a system of coupled oscillators. Finally, this Dissertation concludes by describing ongoing experiments which utilize this new technology to examine topology induced transitions of synchronization dynamics of diffusively coupled chemical oscillators.

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

Role of Structural Asymmetry in Controlling Drop Spacing in Microfluidic Ladder Networks

NASA Astrophysics Data System (ADS)

Wang, William; Maddala, Jeevan; Vanapalli, Siva; Rengasamy, Raghunathan

2012-02-01

Manipulation of drop spacing is crucial to many processes in microfluidic devices including drop coalescence, detection and storage. Microfluidic ladder networks ---where two droplet-carrying parallel channels are connected by narrow bypass channels through which the motion of drops is forbidden---have been proposed as a means to control relative separation between pairs of drops. Prior studies in microfluidic ladder networks with vertical bypasses, which possess fore-aft structural symmetry, have revealed that pairs of drops can only undergo reduction in drop spacing at the ladder exit. We investigate the dynamics of drops in microfluidic ladder networks with both vertical and slanted bypasses. Our analytical results indicate that unlike symmetric ladder networks, structural asymmetry introduced by a single slanted bypass can be used to modulate the relative spacing between drops, enabling them to contract, synchronize, expand or even flip at the ladder exit. Our experiments confirm all the behaviors predicted by theory. Numerical analysis further shows that ladders containing several identical bypasses can only linearly transform the input drop spacing. Finally, we find that ladders with specific combinations of vertical and slanted bypasses can generate non-linear transformation of input drop spacing, despite the absence of drop decision-making events at the bypass junctions.

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.

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.

Calculation of water drop trajectories to and about arbitrary three-dimensional lifting and nonlifting bodies in potential airflow

NASA Technical Reports Server (NTRS)

Norment, H. G.

1985-01-01

Subsonic, external flow about nonlifting bodies, lifting bodies or combinations of lifting and nonlifting bodies is calculated by a modified version of the Hess lifting code. Trajectory calculations can be performed for any atmospheric conditions and for all water drop sizes, from the smallest cloud droplet to large raindrops. Experimental water drop drag relations are used in the water drop equations of motion and effects of gravity settling are included. Inlet flow can be accommodated, and high Mach number compressibility effects are corrected for approximately. Seven codes are described: (1) a code used to debug and plot body surface description data; (2) a code that processes the body surface data to yield the potential flow field; (3) a code that computes flow velocities at arrays of points in space; (4) a code that computes water drop trajectories from an array of points in space; (5) a code that computes water drop trajectories and fluxes to arbitrary target points; (6) a code that computes water drop trajectories tangent to the body; and (7) a code that produces stereo pair plots which include both the body and trajectories. Accuracy of the calculations is discussed, and trajectory calculation results are compared with prior calculations and with experimental data.

Type testing of the Siemens Plessey electronic personal dosemeter.

PubMed

Hirning, C R; Yuen, P S

1995-07-01

This paper presents the results of a laboratory assessment of the performance of a new type of personal dosimeter, the Electronic Personal Dosemeter made by Siemens Plessey Controls Limited. Twenty pre-production dosimeters and a reader were purchased by Ontario Hydro for the assessment. Tests were performed on radiological performance, including reproducibility, accuracy, linearity, detection threshold, energy response, angular response, neutron response, and response time. There were also tests on the effects of a variety of environmental factors, such as temperature, humidity, pulsed magnetic and electric fields, low- and high-frequency electromagnetic fields, light exposure, drop impact, vibration, and splashing. Other characteristics that were tested were alarm volume, clip force, and battery life. The test results were compared with the relevant requirements of three standards: an Ontario Hydro standard for personal alarming dosimeters, an International Electrotechnical Commission draft standard for direct reading personal dose monitors, and an International Electrotechnical Commission standard for thermoluminescence dosimetry systems for personal monitoring. In general, the performance of the Electronic Personal Dosemeter was found to be quite acceptable: it met most of the relevant requirements of the three standards. However, the following deficiencies were found: slow response time; sensitivity to high-frequency electromagnetic fields; poor resistance to dropping; and an alarm that was not loud enough. In addition, the response of the electronic personal dosimeter to low-energy beta rays may be too low for some applications. Problems were experienced with the reliability of operation of the pre-production dosimeters used in these tests.

NASA Ares I Launch Vehicle First Stage Roll Control System Cold Flow Development Test Program Overview

NASA Technical Reports Server (NTRS)

Butt, Adam; Popp, Christopher G.; Holt, Kimberly A.; Pitts, Hank M.

2010-01-01

The Ares I launch vehicle is the selected design, chosen to return humans to the moon, Mars, and beyond. It is configured in two inline stages: the First Stage is a Space Shuttle derived five-segment Solid Rocket Booster and the Upper Stage is powered by a Saturn V derived J-2X engine. During launch, roll control for the First Stage (FS) is handled by a dedicated Roll Control System (RoCS) located on the connecting Interstage. That system will provide the Ares I with the ability to counteract induced roll torque while any induced yaw or pitch moments are handled by vectoring of the booster nozzle. This paper provides an overview of NASA s Ares I FS RoCS cold flow development test program including detailed test objectives, types of tests run to meet those objectives, an overview of the results, and applicable lessons learned. The test article was built and tested at the NASA Marshall Space Flight Center in Huntsville, AL. The FS RoCS System Development Test Article (SDTA) is a full scale, flight representative water flow test article whose primary objective was to obtain fluid system performance data to evaluate integrated system level performance characteristics and verify analytical models. Development testing and model correlation was deemed necessary as there is little historical precedent for similar large flow, pulsing systems such as the FS RoCS. The cold flow development test program consisted of flight-similar tanks, pressure regulators, and thruster valves, as well as plumbing simulating flight geometries, combined with other facility grade components and structure. Orifices downstream of the thruster valves were used to simulate the pressure drop through the thrusters. Additional primary objectives of this test program were to: evaluate system surge pressure (waterhammer) characteristics due to thruster valve operation over a range of mission duty cycles at various feed system pressures, evaluate temperature transients and heat transfer in the pressurization system, including regulator blowdown and propellant ullage performance, measure system pressure drops for comparison to analysis of tubing and components, and validate system activation and re-activation procedures for the helium pressurant system. Secondary objectives included: validating system processes for loading, unloading, and purging, validating procedures and system response for multiple failure scenarios, including relief valve operation, and evaluating system performance for contingency scenarios. The test results of the cold flow development test program are essential in validating the performance and interaction of the Roll Control System and anchoring analysis tools and results to a Critical Design Review level of fidelity.

Environmental and reliability test of FBG based geophone as geophysical exploration instrument

NASA Astrophysics Data System (ADS)

Zhang, Xiaolei; Min, Li; Li, Ming; Jiang, Shaodong; Zhang, Faxiang; Sun, Zhihui; Ni, Jiasheng; Peng, Gangding; Wang, Chang

2017-10-01

A fiber Bragg grating (FBG) based geophone is designed for low-frequency signal detection has high acceleration response of about 60 dB re pm/g in a low frequency range of 5 Hz 60 Hz. To Guarantee normal operation in field test and practical application, an acceleration amplitude restriction is added in the mechanical design of the FBG geophone. Then a series of environmental and reliability test have been proceeded with online or offline monitoring of its working performance, including high and low temperature test, vibration test, shock test and free drop test. All the tests are planned according to National standard or Oil & Gas Industry Standard. And the experimental results indicate that our FBG geophone meet the criterion of oil and gas industry product and is capable of field application.

Synchronous Half-Wave Rectifier

NASA Technical Reports Server (NTRS)

Rippel, Wally E.

1989-01-01

Synchronous rectifying circuit behaves like diode having unusually low voltage drop during forward-voltage half cycles. Circuit particularly useful in power supplies with potentials of 5 Vdc or less, where normal forward-voltage drops in ordinary diodes unacceptably large. Fabricated as monolithic assembly or as hybrid. Synchronous half-wave rectifier includes active circuits to attain low forward voltage drop and high rectification efficiency.

[Effects of false memories on the Concealed Information Test].

PubMed

Zaitsu, Wataru

2012-10-01

The effects of false memories on polygraph examinations with the Concealed Information Test (CIT) were investigated by using the Deese-Roediger-McDermott (DRM) paradigm, which allows participants to evoke false memories. Physiological responses to questions consisting of learned, lure, and unlearned items were measured and recorded. The results indicated that responses to lure questions showed critical responses to questions about learned items. These responses included repression of respiration, an increase in electrodermal activity, and a drop in heart rate. These results suggest that critical response patterns are generated in the peripheral nervous system by true and false memories.

Space shuttle orbiter mechanical refrigeration system

NASA Technical Reports Server (NTRS)

Williams, J. L.

1974-01-01

A radiator/condenser was designed which is efficient in both condensation (refrigeration) and liquid phase (radiator) operating modes, including switchover from the refrigeration mode to the radiator mode and vice versa. A method for predicting the pressure drop of a condensing two-phase flow in zero-gravity was developed along with a method for predicting the flow regime which would prevail along the condensation path. The hybrid refrigeration system was assembled with the two radiator/condenser panels installed in a space environment simulator. The system was tested under both atmospheric and vacuum conditions. Results of the tests are presented.

Highlights of the high-temperature falling particle receiver project: 2012 - 2016

NASA Astrophysics Data System (ADS)

Ho, C. K.; Christian, J.; Yellowhair, J.; Jeter, S.; Golob, M.; Nguyen, C.; Repole, K.; Abdel-Khalik, S.; Siegel, N.; Al-Ansary, H.; El-Leathy, A.; Gobereit, B.

2017-06-01

A 1 MWt continuously recirculating falling particle receiver has been demonstrated at Sandia National Laboratories. Free-fall and obstructed-flow receiver designs were tested with particle mass flow rates of ˜1 - 7 kg/s and average irradiances up to 1,000 suns. Average particle outlet temperatures exceeded 700 °C for the free-fall tests and reached nearly 800 °C for the obstructed-flow tests, with peak particle temperatures exceeding 900 °C. High particle heating rates of ˜50 to 200 °C per meter of illuminated drop length were achieved for the free-fall tests with mass flow rates ranging from 1 - 7 kg/s and for average irradiances up to ˜ 700 kW/m2. Higher temperatures were achieved at the lower particle mass flow rates due to less shading. The obstructed-flow design yielded particle heating rates over 300 °C per meter of illuminated drop length for mass flow rates of 1 - 3 kg/s for irradiances up to ˜1,000 kW/m2. The thermal efficiency was determined to be ˜60 - 70% for the free-falling particle tests and up to ˜80% for the obstructed-flow tests. Challenges encountered during the tests include particle attrition and particle loss through the aperture, reduced particle mass flow rates at high temperatures due to slot aperture narrowing and increased friction, and deterioration of the obstructed-flow structures due to wear and oxidation. Computational models were validated using the test data and will be used in future studies to design receiver configurations that can increase the thermal efficiency.

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.

Climatology of atmospheric PM10 concentration in the Po Valley

NASA Astrophysics Data System (ADS)

Bigi, A.; Ghermandi, G.

2014-01-01

The limits to atmospheric pollutant concentration set by the European Commission provide a challenging target for the municipalities in the Po Valley, because of the characteristic climatic conditions and high population density of this region. In order to assess climatology and trends in the concentration of atmospheric particles in the Po Valley, a dataset of PM10 data from 41 sites across the Po Valley have been analysed, including both traffic and background sites (either urban, suburban or rural). Of these 41 sites, 18 with 10 yr or longer record have been analysed for long term trend in de-seasonalized monthly means, in annual quantiles and in monthly frequency distribution. A widespread significant decreasing trend has been observed at most sites, up to few percent per year, by Generalised Least Square and Theil-Sen method. All 41 sites have been tested for significant weekly periodicity by Kruskal-Wallis test for mean anomalies and by Wilcoxon test for weekend effect magnitude. A significant weekly periodicity has been observed for most PM10 series, particularly in summer and ascribed mainly to anthropic particulate emissions. A cluster analysis has been applied in order to highlight stations sharing similar pollution conditions over the reference period. Five clusters have been found, two gathering the metropolitan areas of Torino and Milano and their respective nearby sites and the other three clusters gathering north-east, north-west and central Po Valley sites respectively. Finally the observed trends in atmospheric PM10 have been compared to trends in provincial emissions of particulates and PM precursors, and analysed along with data on vehicular fleet age, composition and fuel sales. Significant basin-wide drop in emissions occurred for gaseous pollutants, contrarily to emissions of PM10 and PM2.5, whose drop resulted low and restricted to few provinces. It is not clear whether the decrease for only gaseous emissions is sufficient to explain the observed drop in atmospheric PM10, or if the low drop in particulate emissions is indeed due to the uncertainty in the emission inventory data for this species.

Long-term trend and variability of atmospheric PM10 concentration in the Po Valley

NASA Astrophysics Data System (ADS)

Bigi, A.; Ghermandi, G.

2014-05-01

The limits to atmospheric pollutant concentration set by the European Commission provide a challenging target for the municipalities in the Po Valley, because of the characteristic climatic conditions and high population density of this region. In order to assess climatology and trends in the concentration of atmospheric particles in the Po Valley, a data set of PM10 data from 41 sites across the Po Valley have been analysed, including both traffic and background sites (either urban, suburban or rural). Of these 41 sites, 18 with 10 yr or longer record have been analysed for long-term trend in deseasonalized monthly means, in annual quantiles and in monthly frequency distribution. A widespread significant decreasing trend has been observed at most sites, up to a few percent per year, by a generalized least squares and Theil-Sen method. All 41 sites have been tested for significant weekly periodicity by Kruskal-Wallis test for mean anomalies and by Wilcoxon test for weekend effect magnitude. A significant weekly periodicity has been observed for most PM10 series, particularly in summer and ascribed mainly to anthropic particulate emissions. A cluster analysis has been applied in order to highlight stations sharing similar pollution conditions over the reference period. Five clusters have been found, two encompassing the metropolitan areas of Turin and Milan and their respective nearby sites and the other three clusters gathering northeast, northwest and central Po Valley sites respectively. Finally, the observed trends in atmospheric PM10 have been compared to trends in provincial emissions of particulates and PM precursors, and analysed along with data on vehicular fleet age, composition and fuel sales. A significant basin-wide drop in emissions occurred for gaseous pollutants, contrarily to emissions of PM10 and PM2.5, whose drop was low and restricted to a few provinces. It is not clear whether the decrease for only gaseous emissions is sufficient to explain the observed drop in atmospheric PM10, or if the low drop in particulate emissions is indeed due to the uncertainty in the emission inventory data for this species.

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.

Science Support for Space-Based Droplet Combustion: Drop Tower Experiments and Detailed Numerical Modeling

NASA Technical Reports Server (NTRS)

Marchese, Anthony J.; Dryer, Frederick L.

1997-01-01

This program supports the engineering design, data analysis, and data interpretation requirements for the study of initially single component, spherically symmetric, isolated droplet combustion studies. Experimental emphasis is on the study of simple alcohols (methanol, ethanol) and alkanes (n-heptane, n-decane) as fuels with time dependent measurements of drop size, flame-stand-off, liquid-phase composition, and finally, extinction. Experiments have included bench-scale studies at Princeton, studies in the 2.2 and 5.18 drop towers at NASA-LeRC, and both the Fiber Supported Droplet Combustion (FSDC-1, FSDC-2) and the free Droplet Combustion Experiment (DCE) studies aboard the shuttle. Test matrix and data interpretation are performed through spherically-symmetric, time-dependent numerical computations which embody detailed sub-models for physical and chemical processes. The computed burning rate, flame stand-off, and extinction diameter are compared with the respective measurements for each individual experiment. In particular, the data from FSDC-1 and subsequent space-based experiments provide the opportunity to compare all three types of data simultaneously with the computed parameters. Recent numerical efforts are extending the computational tools to consider time dependent, axisymmetric 2-dimensional reactive flow situations.

Two-phase gas-liquid flow characteristics inside a plate heat exchanger

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

Nilpueng, Kitti; Wongwises, Somchai

In the present study, the air-water two-phase flow characteristics including flow pattern and pressure drop inside a plate heat exchanger are experimentally investigated. A plate heat exchanger with single pass under the condition of counter flow is operated for the experiment. Three stainless steel commercial plates with a corrugated sinusoidal shape of unsymmetrical chevron angles of 55 and 10 are utilized for the pressure drop measurement. A transparent plate having the same configuration as the stainless steel plates is cast and used as a cover plate in order to observe the flow pattern inside the plate heat exchanger. The air-watermore » mixture flow which is used as a cold stream is tested in vertical downward and upward flow. The results from the present experiment show that the annular-liquid bridge flow pattern appeared in both upward and downward flows. However, the bubbly flow pattern and the slug flow pattern are only found in upward flow and downward flow, respectively. The variation of the water and air velocity has a significant effect on the two-phase pressure drop. Based on the present data, a two-phase multiplier correlation is proposed for practical application. (author)« less

Clinical, biochemical, and experimental studies on lactation. II. Clinical effects of gestagens on lactation.

PubMed

Kamal, I; Hefnawi, F; Ghoneim, M; Talaat, M; Younis, N; Tagui, A; Abdalla, M

1969-10-01

To measure the effect of steroid contraceptives on lactation and baby's growth, 120 Egyptian women were given steroids in a double-blind study from 6-10 weeks postpartum until weaning. Drugs included Lyndiol 2.5 (2.5 mg lynestrenol and .075 mg mestranol, combined), Lyndiol 1 (1 mg lynestrenol and .1 mg mestranol, combined), .5 mg lynestrenol alone, continuously, Deladroxate injection (150 mg dihydroxyprogesterone acetophenide and 10 mg estradiol enanthate, monthly), and placebo with IUD. Tests were conducted bimonthly until baby was 24 weeks, then monthly, and consisted of weighing the infant before and after suckling at 9 and 12 a.m., and weighing milk pumped from the other breast before each feeding. Average age of infant at beginning of supplementary feeding was younger than with previous children in all groups, but 23.6 weeks younger with Deladroxate and 28.2 weeks with Lyndiol 2.5. Milk yield measurements were higher from weighing the baby, but more accurate with the pump. Results, figured as percent adequacy based on infant weight, showed 50% for placebo and no drop, 45 and 46% drop after 12 weeks with Lyndiol 1 and Lyndiol 2.5, 25% drop with Deladroxate, and 20% drop with .5 mg lynestrenol. Children's growth curves were within normal range but dropped below 10th percentile for those whose mothers were given Lyndiol 2.5 or Deladroxate injection. These 2 groups of babies lost weight in the first 4 weeks and 5 died of gastroenteritis: 3 from the Deladroxate group and 2 from the Lyndiol 2.5 group. The continuous lynestrenol pill was the least harmful of the medications by all criteria.

Modeling drop impacts on inclined flowing soap films

NASA Astrophysics Data System (ADS)

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

2015-11-01

Small drops impinging on soap films flowing at an angle primarily exhibit three fundamental regimes of post-impact dynamics: (a) the drop bounces off the film surface, (b) it coalesces with the downstream flow, and (c) it pierces through the film. During impact, the drop deforms along with a simultaneous, almost elastic deformation of the film transverse to the stream direction. Hence, the governing dynamics for this interaction present the rare opportunity to explore the in-tandem effects of elasticity and hydrodynamics alike. In this talk, we outline the analytical framework to study the drop impact dynamics. The model assumes a deformable drop and a deformable three-dimensional soap film and invokes a parametric study to qualify the three mentioned impact types. The physical parameters include the impact angle, drop impact speed, and the diameters of the drop prior to and during impact when it deforms and spreads out. Our model system offers a path towards optimization of interactions between a spray and a flowing liquid.

Trapping of drops by wetting defects

PubMed Central

't Mannetje, Dieter; Ghosh, Somnath; Lagraauw, Rudy; Otten, Simon; Pit, Arjen; Berendsen, Christian; Zeegers, Jos; van den Ende, Dirk; Mugele, Frieder

2014-01-01

Controlling the motion of drops on solid surfaces is crucial in many natural phenomena and technological processes including the collection and removal of rain drops, cleaning technology and heat exchangers. Topographic and chemical heterogeneities on solid surfaces give rise to pinning forces that can capture and steer drops in desired directions. Here we determine general physical conditions required for capturing sliding drops on an inclined plane that is equipped with electrically tunable wetting defects. By mapping the drop dynamics on the one-dimensional motion of a point mass, we demonstrate that the trapping process is controlled by two dimensionless parameters, the trapping strength measured in units of the driving force and the ratio between a viscous and an inertial time scale. Complementary experiments involving superhydrophobic surfaces with wetting defects demonstrate the general applicability of the concept. Moreover, we show that electrically tunable defects can be used to guide sliding drops along actively switchable tracks—with potential applications in microfluidics. PMID:24721935

Outcome regimes of binary raindrop collisions

NASA Astrophysics Data System (ADS)

Testik, Firat Y.

2009-11-01

This study delineates the physical conditions that are responsible for the occurrence of main outcome regimes (i.e., bounce, coalescence, and breakup) for binary drop collisions with a precipitation microphysics perspective. Physical considerations based on the collision kinetic energy and the surface energies of the colliding drops lead to the development of a theoretical regime diagram for the drop/raindrop collision outcomes in the We- p plane ( We — Weber number, p — raindrop diameter ratio). This theoretical regime diagram is supported by laboratory experimental observations of drop collisions using high-speed imaging. Results of this fundamental study bring in new insights into the quantitative understanding of drop dynamics, applications of which extend beyond precipitation microphysics. In particular, results of this drop collision study are expected to give impetus to the physics-based dynamic modeling of the drop size distributions that is essential for various typical modern engineering applications, including numerical modeling of evolution of raindrop size distribution in rain shaft.

Automatic Control of Arc Process for Making Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Scott, Carl D.; Pulumbarit, Robert B.; Victor, Joe

2004-01-01

An automatic-control system has been devised for a process in which carbon nanotubes are produced in an arc between a catalyst-filled carbon anode and a graphite cathode. The control system includes a motor-driven screw that adjusts the distance between the electrodes. The system also includes a bridge circuit that puts out a voltage proportional to the difference between (1) the actual value of potential drop across the arc and (2) a reference value between 38 and 40 V (corresponding to a current of about 100 A) at which the yield of carbon nanotubes is maximized. Utilizing the fact that the potential drop across the arc increases with the interelectrode gap, the output of the bridge circuit is fed to a motor-control circuit that causes the motor to move the anode toward or away from the cathode if the actual potential drop is more or less, respectively, than the reference potential. Thus, the system regulates the interelectrode gap to maintain the optimum potential drop. The system also includes circuitry that records the potential drop across the arc and the relative position of the anode holder as function of time.

Compound Capillary Flows in Complex Containers: Drop Tower Test Results

NASA Astrophysics Data System (ADS)

Bolleddula, Daniel A.; Chen, Yongkang; Semerjian, Ben; Tavan, Noël; Weislogel, Mark M.

2010-10-01

Drop towers continue to provide unique capabilities to investigate capillary flow phenomena relevant to terrestrial and space-based capillary fluidics applications. In this study certain `capillary rise' flows and the value of drop tower experimental investigations are briefly reviewed. A new analytic solution for flows along planar interior edges is presented. A selection of test cell geometries are then discussed where compound capillary flows occur spontaneously and simultaneously over local and global length scales. Sample experimental results are provided. Tertiary experiments on a family of asymmetric geometries that isolate the global component of such flows are then presented along with a qualitative analysis that may be used to either avoid or exploit such flows. The latter may also serve as a design tool with which to assess the impact of inadvertent container asymmetry.

Custom Unit Pump Design and Testing for the EVA PLSS

NASA Technical Reports Server (NTRS)

Schuller, Michael; Kurwitz, Cable; Goldman, Jeff; Morris, Kim; Trevino, Luis

2009-01-01

This paper describes the effort by the Texas Engineering Experiment Station (TEES) and Honeywell for NASA to design and test a pre-flight prototype pump for use in the Extra-vehicular activity (EVA) portable life support subsystem (PLSS). Major design decisions were driven by the need to reduce the pump s mass, power, and volume compared to the existing PLSS pump. In addition, the pump must accommodate a much wider range of abnormal conditions than the existing pump, including vapor/gas bubbles and increased pressure drop when employed to cool two suits simultaneously. A positive displacement, external gear type pump was selected because it offers the most compact and highest efficiency solution over the required range of flow rates and pressure drops. An additional benefit of selecting a gear pump design is that it is self priming and capable of ingesting non-condensable gas without becoming air locked. The chosen pump design consists of a 28 V DC, brushless, sealless, permanent magnet motor driven, external gear pump that utilizes a Honeywell development that eliminates the need for magnetic coupling. Although the planned flight unit will use a sensorless motor with custom designed controller, the pre-flight prototype to be provided for this project incorporates Hall effect sensors, allowing an interface with a readily available commercial motor controller. This design approach reduced the cost of this project and gives NASA more flexibility in future PLSS laboratory testing. The pump design was based on existing Honeywell designs, but incorporated features specifically for the PLSS application, including all of the key features of the flight pump. Testing at TEES verified that the pump meets the design requirements for range of flow rates, pressure drop, power consumption, working fluid temperature, operating time, gas ingestion , and restart capability under both ambient and vacuum conditions. The pump operated between 40 and 240 lbm/hr flowrate, 35 to 100 F pump temperature range, and 5 to 10 psid pressure rise. Power consumption of the pump controller at the nominal operating point in both ambient and vacuum conditions was 9.5 W, which was less than the 12 W predicted. Gas ingestion capabilities were tested by injecting 100 cc of air into the fluid line; the pump operated normally throughout this test. The test results contained a number of anomalies, specifically power increases and a few flow stoppages, that prompted TEES and Honeywell to disassemble and inspect the pump. Inspection indicated contamination in the pump and fit issues may have played roles in the observed anomalies. Testing following reassembly indicated that the performance of the pump 1) matched both the predicted performance values, 2) the performance values measured prior to disassembly, and 3) was free of the anomalies noted in the pre-disassembly testing.

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

Drop-out phagemid vector for switching from phage displayed affinity reagents to expression formats.

PubMed

Pershad, Kritika; Sullivan, Mark A; Kay, Brian K

2011-05-15

Affinity reagents that are generated by phage display are typically subcloned into an expression vector for further biochemical characterization. This insert transfer process is time consuming and laborious especially if many inserts are to be subcloned. To simplify the transfer process, we have constructed a "drop-out" phagemid vector that can be rapidly converted to an expression vector by a simple restriction enzyme digestion with MfeI (to "drop-out" the gene III coding sequence), which generates alkaline phosphatase (AP) fusions of the affinity reagents on religation. Subsequently, restriction digestion with AscI drops out the AP coding region and religation generates affinity reagents with a C-terminal six-histidine tag. To validate the usefulness of this vector, four different human single chain Fragments of variable regions (scFv) were tested, three of which show specific binding to three zebrafish (Danio rerio) proteins, namely suppression of tumorigenicity 13, recoverin, and Ppib and the fourth binds to human Lactoferrin protein. For each of the constructs tested, the gene III and AP drop-out efficiency was between 90% and 100%. This vector is especially useful in speeding up the downstream screening of affinity reagents and bypassing the time-consuming subcloning experiments. Copyright © 2011 Elsevier Inc. All rights reserved.

Application of hanging drop technique for stem cell differentiation and cytotoxicity studies.

PubMed

Banerjee, Meenal; Bhonde, Ramesh R

2006-05-01

The aim of our study is to explore the possibility of using an ancient method of culture technique- the hanging drop technique for stem cell differentiation and cytotoxicity testing. We demonstrate here a variety of novel applications of this age old technique not only to harness the differentiation potential of stem cells into specific lineages but also for cytotoxicity studies. Here we have prepared hanging drop cultures by placing 20 microl micro-drops of nutrient media and 10% Fetal Calf Serum (FCS) containing cells of interest on the lids of 60 mm dishes. Bottom plates of the dishes were filled with sterile Phosphate Buffer Saline (PBS) to avoid desiccation of samples. Lids were then placed on the bottom plates to achieve hanging drop cultures. We utilized this technique for cultivation of ciliated epithelia to study cytotoxicity and differentiation of bone marrow stromal cells. Most importantly the modified culture technique presented here is simple, economical and cost effective in terms of the time taken and the reagents required and are amenable to goal specific modification such as cytotoxicity testing. It is advantageous over the existing system in terms of retention of viability and functionality for longer duration and for providing three dimensional growth micro-environment making it useful for organotypic cultures and in vivo simulation.

Solid surface wetting and the deployment of drops in microgravity

NASA Technical Reports Server (NTRS)

Trinh, E. H.; Depew, J.

1994-01-01

The complete or partial deployment of liquid samples in low gravity is primarily influenced by the interfacial properties of the specific liquid and solid materials used because the overwhelming bias of the Earth gravitational acceleration is removed. This study addresses the engineering aspects of injecting and deploying drops of prescribed volume into an acoustic positioning chamber in microgravity. The specific problems of interest are the design, testing, and implementation of injector tips to be used in a simultaneously retracting dual-injector system in the Drop Physics Module microgravity experiment facility. Prior to release, the liquid to be deployed must be retained within a restricted area at the very end of the injectors under dynamic stimuli from the continuous injection flow as well as from the stepped motion of the injectors. The final released drop must have a well determined volume and negligible residual linear or angular momentum. The outcome of Earth-based short-duration low gravity experiments had been the selection of two types of injector tips which were flown as back-up parts. They were successfully utilized during the USML-1 Spacelab mission as the primary tips. The combination of a larger contact surface, liquid pinning with a sharp edge, and selective coating of strategic tip surfaces with a non-wetting compound has allowed a significant increase in the success rate of deployment of simple and compound drops of aqueous solutions of glycerol and silicone oil. The diameter of the samples studied in the Drop Physics Module range between 0.3 and 2.7 cm. The tests conducted on-orbit with a manually operated small device have allowed the calibration of the volume deployed for a few drop sizes. The design for improved tips to be used during the next USML flight is based on these results.

Solid Surface Wetting and the Deployment of Drops in Microgravity

NASA Technical Reports Server (NTRS)

Trinh, E. H.; Depew, J.

1994-01-01

The complete or partial deployment of liquid samples in low gravity is primarily influenced by the interfacial properties of the specific liquid and solid materials used because the overwhelming bias of the Earth gravitational acceleration is removed. This study addresses the engineering aspects of injecting and deploying drops of prescribed volume into an acoustic positioning chamber in microgravity. The specific problems of interest are the design, testing, and implementation of injector tips to be used in a simuttaneously retracting dual-injector system used in the Drop Physics Module microgravity experiment facility. Prior to release, the liquid to be deployed must be retained within a restricted area at the very end of the injectors even under dynamic stimuli due to continuous injection flow as well as to the stepped motion of the injectors, and the final released drop must have a well determined volume as well as negligible residual linear or angular momentum from the deployment process. The outcome of Earthbased short-duration low gravity experiments had been the selection of two types of injector tips which were flown as back-up parts and were successfully utilized during the USML-1 Spacelab mission. The combination of a larger contact surface, liquid pinning with a sharp edge, and selective coating of strategic tip surfaces with a non-wetting compound has allowed a significant increase in the success rate of deployment of simple and compound drops of aqueous solutions of glycerol and silicone oil. The diameter of the samples studied in the Drop Physics Module ranged between 0.3 and 2.7 cm. The tests conducted onsrbit with a manually operated small device have allowed the calibration of the volume deployed for a few drop sizes. The design for improved tips to be used during the next USML flight is based on these results.

Finger force changes in the absence of visual feedback in patients with Parkinson’s disease

PubMed Central

Jo, Hang Jin; Ambike, Satyajit; Lewis, Mechelle M.; Huang, Xuemei; Latash, Mark L.

2015-01-01

Objectives We investigated the unintentional drift in total force and in sharing of the force between fingers in two-finger accurate force production tasks performed without visual feedback by patients with Parkinson’s disease (PD) and healthy controls. In particular, we were testing a hypothesis that adaptation to the documented loss of action stability could lead to faster force drop in PD. Methods PD patients and healthy controls performed accurate constant force production tasks without visual feedback by different finger pairs, starting with different force levels and different sharing patterns of force between the two fingers. Results Both groups showed an exponential force drop with time and a drift of the sharing pattern towards 50:50. The PD group showed a significantly faster force drop without a change in speed of the sharing drift. These results were consistent across initial force levels, sharing patterns, and finger pairs. A pilot test of four subjects, two PD and two controls, showed no consistent effects of memory on the force drop. Conclusions We interpret the force drop as a consequence of back-coupling between the actual and referent finger coordinates that draws the referent coordinate towards the actual one. The faster force drop in the PD group is interpreted as adaptive to the loss of action stability in PD. The lack of group differences in the sharing drift suggests two potentially independent physiological mechanisms contributing to the force and sharing drifts. Significance The hypothesis on adaptive changes in PD with the purpose to ensure stability of steady states may have important implications for treatment of PD. The speed of force drop may turn into a useful tool to quantify such adaptive changes. PMID:26072437

Correlation Of Giant Nuclei With Cloud Droplet Concentration

NASA Astrophysics Data System (ADS)

Jha, V.; Hudson, J. G.; Noble, S.

2011-12-01

The effect of giant nuclei (GN; larger than 1 micrometer particles produced by wind on the ocean surface) on warm rain has been debated for decades. During RICO (Rain in Cumulus over the Ocean) Hudson et al. (2011) found a negative correlation (R) between CCN concentrations at 1% supersaturation (S) and large cloud droplet concentrations (Fig. 1A). This reversal from positive R for CCN with total (or small) cloud droplet concentrations (left side of Fig. 1A) was explained by the greater competition for condensate, which thus limits droplet sizes when CCN concentrations are higher. The negative R increased in magnitude with altitude, and the droplet size where the maximum negative R occurred increased with altitude (Fig. 1A). However, at all altitudes this negative R decreased in magnitude for even larger cloud and drizzle drops (right side of Fig. 1A except highest altitude). The decrease in magnitude of the negative R was greater for increasing drop sizes at higher altitudes. Thus, at the higher altitudes, R for CCN with large drizzle drops was of low negative magnitude and even positive at the highest RICO altitudes. The disparity between CCN and drizzle drop concentrations precluded a causal relationship. But the high R between GN and drizzle drop concentrations at the highest altitudes (Fig. 1B) and the comparable concentrations indicated that GN were engendering drizzle. This is supported by the increasing R with altitude of the GN-drizzle drop R (right side of Fig. 1B). The conclusion of a GN-drizzle connection is also supported by the fact that CCN concentrations should inhibit drizzle. This analysis of Hudson et al. (2011) is here expanded to include correlations of CCN concentrations at lower S with cloud and drizzle drop concentrations to investigate intermediate relationships; i.e., between large nuclei (i.e., 0.1-1 micrometer; critical S 0.1-0.01%) and drizzle drop concentrations. A shortcoming of Hudson et al. (2011) was the small number of high altitude flights, which limited the significance of the R values. The very recent (July 2011) ICE-T project was a similar study in the same region (Caribbean). The greater number of high altitude cloud measurements during the summer season should provide better statistics to test the GN warm rain hypothesis.

The silicon-glass microreactor with embedded sensors—technology and results of preliminary qualitative tests, toward intelligent microreaction plant

NASA Astrophysics Data System (ADS)

Knapkiewicz, P.

2013-03-01

The technology and preliminary qualitative tests of silicon-glass microreactors with embedded pressure and temperature sensors are presented. The concept of microreactors for leading highly exothermic reactions, e.g. nitration of hydrocarbons, and design process-included computer-aided simulations are described in detail. The silicon-glass microreactor chip consisting of two micromixers (multistream micromixer), reaction channels, cooling/heating chambers has been proposed. The microreactor chip was equipped with a set of pressure and temperature sensors and packaged. Tests of mixing quality, pressure drops in channels, heat exchange efficiency and dynamic behavior of pressure and temperature sensors were documented. Finally, two applications were described.

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.

Influence of Computational Drop Representation in LES of a Droplet-Laden Mixing Layer

NASA Technical Reports Server (NTRS)

Bellan, Josette; Radhakrishnan, Senthilkumaran

2013-01-01

Multiphase turbulent flows are encountered in many practical applications including turbine engines or natural phenomena involving particle dispersion. Numerical computations of multiphase turbulent flows are important because they provide a cheaper alternative to performing experiments during an engine design process or because they can provide predictions of pollutant dispersion, etc. Two-phase flows contain millions and sometimes billions of particles. For flows with volumetrically dilute particle loading, the most accurate method of numerically simulating the flow is based on direct numerical simulation (DNS) of the governing equations in which all scales of the flow including the small scales that are responsible for the overwhelming amount of dissipation are resolved. DNS, however, requires high computational cost and cannot be used in engineering design applications where iterations among several design conditions are necessary. Because of high computational cost, numerical simulations of such flows cannot track all these drops. The objective of this work is to quantify the influence of the number of computational drops and grid spacing on the accuracy of predicted flow statistics, and to possibly identify the minimum number, or, if not possible, the optimal number of computational drops that provide minimal error in flow prediction. For this purpose, several Large Eddy Simulation (LES) of a mixing layer with evaporating drops have been performed by using coarse, medium, and fine grid spacings and computational drops, rather than physical drops. To define computational drops, an integer NR is introduced that represents the ratio of the number of existing physical drops to the desired number of computational drops; for example, if NR=8, this means that a computational drop represents 8 physical drops in the flow field. The desired number of computational drops is determined by the available computational resources; the larger NR is, the less computationally intensive is the simulation. A set of first order and second order flow statistics, and of drop statistics are extracted from LES predictions and are compared to results obtained by filtering a DNS database. First order statistics such as Favre averaged stream-wise velocity, Favre averaged vapor mass fraction, and the drop stream-wise velocity, are predicted accurately independent of the number of computational drops and grid spacing. Second order flow statistics depend both on the number of computational drops and on grid spacing. The scalar variance and turbulent vapor flux are predicted accurately by the fine mesh LES only when NR is less than 32, and by the coarse mesh LES reasonably accurately for all NR values. This is attributed to the fact that when the grid spacing is coarsened, the number of drops in a computational cell must not be significantly lower than that in the DNS.

Young People's Use and Views of a School-Based Sexual Health Drop-In Service in Areas of High Deprivation

ERIC Educational Resources Information Center

Ingram, Jenny; Salmon, Debra

2010-01-01

Objective: To describe patterns and reasons of attendance and young people's views of the drop-in service. Design: Analysis of a prospective database, questionnaire survey and qualitative interviews and discussions. Setting: Sexual health drop-in clinics in 16 secondary schools (including three pupil-referral units) in deprived areas of a city in…

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…

LASIK and dry eye.

PubMed

Toda, Ikuko

2007-01-01

Dry eye is one of the most common complications after laser-assisted in situ keratomileusis (LASIK). The clinical signs of post-LASIK dry eye include positive vital staining of ocular surface, decreased tear film breakup time and Schirmer test, reduced corneal sensitivity, and decreased functional visual acuity. The symptoms and signs last at least 1 month after LASIK. Although the mechanisms for developing post-LASIK dry eye are not completely understood, loss of corneal innervation by flap-making may affect the reflex loops of the corneal-lacrimal gland, corneal-blinking, and blinking-meibomian gland, and blinking-meibomian gland, resulting in decreased aqueous and lipid tear secretion and mucin expression. As LASIK enhancement by flap-lifting induces less dry eye symptoms and signs than first surgery, it is suggested that other factors rather than loss of neurotrophic effect may be involved in the mechanisms of post-LASIK dry eye. The treatments of dry eye include artificial tears, topical cyclosporine, hot compress, punctal plugs, and autologous serum eye drops. For patients with severe preoperative dry eye, a combination of punctal plugs and serum eye drops is required to be used before surgery.

Comparison of pressure drop and filtration efficiency of particulate respirators using welding fumes and sodium chloride.

PubMed

Cho, Hyun-Woo; Yoon, Chung-Sik; Lee, Jin-Ho; Lee, Seung-Joo; Viner, Andrew; Johnson, Erik W

2011-07-01

Respirators are used to help reduce exposure to a variety of contaminants in workplaces. Test aerosols used for certification of particulate respirators (PRs) include sodium chloride (NaCl), dioctyl phthalate, and paraffin oil. These aerosols are generally assumed to be worst case surrogates for aerosols found in the workplace. No data have been published to date on the performance of PRs with welding fumes, a hazardous aerosol that exists in real workplace settings. The aim of this study was to compare the performance of respirators and filters against a NaCl aerosol and a welding fume aerosol and determine whether or not a correlation between the two could be made. Fifteen commercial PRs and filters (seven filtering facepiece, two replaceable single-type filters, and six replaceable dual-type filters) were chosen for investigation. Four of the filtering facepiece respirators, one of the single-type filters, and all of the dual-type filters contained carbon to help reduce exposure to ozone and other vapors generated during the welding process. For the NaCl test, a modified National Institute for Occupational Safety and Health protocol was adopted for use with the TSI Model 8130 automated filter tester. For the welding fume test, welding fumes from mild steel flux-cored arcs were generated and measured with a SIBATA filter tester (AP-634A, Japan) and a manometer in the upstream and downstream sections of the test chamber. Size distributions of the two aerosols were measured using a scanning mobility particle sizer. Penetration and pressure drop were measured over a period of aerosol loading onto the respirator or filter. Photos and scanning electron microscope images of clean and exposed respirators were taken. The count median diameter (CMD) and mass median diameter (MMD) for the NaCl aerosol were smaller than the welding fumes (CMD: 74 versus 216 nm; MMD: 198 versus 528 nm, respectively). Initial penetration and peak penetration were higher with the NaCl aerosol. However, pressure drop increased much more rapidly in the welding fume test than the NaCl aerosol test. The data and images clearly show differences in performance trends between respirator models. Therefore, general correlations between NaCl and weld fume data could not be made. These findings suggest that respirators certified with a surrogate test aerosol such as NaCl are appropriate for filtering welding fume (based on penetration). However, some respirators may have a more rapid increase in pressure drop from the welding fume accumulating on the filter. Therefore, welders will need to choose which models are easier to breathe through for the duration of their use and replace respirators or filters according to the user instructions and local regulations.

Contact ice nucleation by submicron atmospheric aerosols

NASA Technical Reports Server (NTRS)

Deshler, T.

1982-01-01

An apparatus designed to measure the concentrations of submicron contact ice nuclei is described. Here, natural forces transfer nuclei to supercooled sample drops suspended in an aerosol stream. Experimental measurements of the scavenging rate of the sample drops for several humidities and aerosol sizes are found to be in agreement with theory to within a factor of two. This fact, together with the statistical tests showing a difference between the data and control samples, is seen as indicating that a reliable measurement of the concentrations of submicron contact ice nuclei has been effected. A figure is included showing the ice nucleus concentrations as a function of temperature and assumed aerosol radius. For a 0.01 micron radius, the average is 1/liter at -15 C and 3/liter at -18 C. It is noted that the measurements are in fair agreement with ice crystal concentrations in stable winter clouds measured over Elk Mountain, WY (Vali et al., 1982).

Lower cognitive performance in 81-year-old men with greater nocturnal blood pressure dipping

PubMed Central

Axelsson, Johan; Reinprecht, Faina; Siennicki-Lantz, Arkadiusz; Elmståhl, Sölve

2008-01-01

Abnormal day-to-night blood pressure (BP) pattern have been found to be associated with cerebrovascular damage, yet studies of the elderly 80 years of age and above, for whom the risk pattern may be different due to ageing and age-associated diseases, are lacking. Ninety-seven 81-year-old men underwent ambulatory BP monitoring and were given six cognitive tests, 79 of the men completing the cognitive test battery. The odds ratio (OR) for performing one standard deviation below the mean on any cognitive test was calculated using a forward stepwise logistic regression model, confounding factors being controlled for. Groups defined in terms of day-to-night changes in BP were compared in this respect. Cognitive performance was lower (OR 3.6; P = 0.017) in the group usually described as dippers (10%–20% nocturnal drop in systolic BP [SBP]) as compared with nondippers (<10% drop). The tertile with the greatest SBP fall (10.6%–19.8%, a range considered as normal among middle aged) showed lowest cognitive performance (OR 4.7; P = 0.008) as compared with the middle tertile (5.1%–10.5% drop). The mean nocturnal fall in SBP was 7.4%, significantly greater in those with lower rather than higher cognitive performance. A nocturnal drop in SBP of ≥10% was associated with lower cognitive performance in these elderly men. The limits to normal dipping appear to be shifted in the direction of a lesser drop in the very elderly. PMID:20428409

Drop impact and wettability: From hydrophilic to superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Antonini, Carlo; Amirfazli, Alidad; Marengo, Marco

2012-10-01

Experiments to understand the effect of surface wettability on impact characteristics of water drops onto solid dry surfaces were conducted. Various surfaces were used to cover a wide range of contact angles (advancing contact angle from 48° to 166°, and contact angle hysteresis from 5° to 56°). Several different impact conditions were analyzed (12 impact velocities on 9 different surfaces, among which 2 were superhydrophobic). Results from impact tests with millimetric drops show that two different regimes can be identified: a moderate Weber number regime (30 < We < 200), in which wettability affects both drop maximum spreading and spreading characteristic time; and a high Weber number regime (We > 200), in which wettability effect is secondary, because capillary forces are overcome by inertial effects. In particular, results show the role of advancing contact angle and contact angle hysteresis as fundamental wetting parameters to allow understanding of different phases of drop spreading and beginning of recoiling. It is also shown that drop spreading on hydrophilic and superhydrophobic surfaces occurs with different time scales. Finally, if the surface is superhydrophobic, eventual impalement, i.e., transition from Cassie to Wenzel wetting state, which might occur in the vicinity of the drop impact area, does not influence drop maximum spreading.

Prevalence of ocular symptoms and signs with preserved and preservative free glaucoma medication

PubMed Central

Pisella, P J; Pouliquen, P; Baudouin, C

2002-01-01

Aim: To determine the incidence of ocular toxicity of preservatives with glaucoma medications. Methods: A prospective epidemiological survey was carried out in 1999 by 249 ophthalmologists on 4107 patients. Ocular symptoms, conjunctiva, cornea, and eyelids were assessed. A χ2 test was used for differences between preserved eye drops (P) and preservative free eye drops (PF). Results: 84% patients used P, 13% received PF, and 3% a combination of P and PF eye drops. All symptoms were more prevalent with P than with PF drops (p<0.001): discomfort upon instillation (43% versus 17%), and symptoms between instillations such as burning-stinging (40% versus 22%), foreign body sensation (31% versus 14%), dry eye sensation (23% versus 14%), tearing (21% versus 14%), and eyelid itching (18% versus 10%). An increased incidence (>2 times) of ocular signs was seen with P eye drops. The prevalence of signs and symptoms was dose dependent, increasing with the number of P drops. A reduction in the symptoms and signs was observed when patients changed from P to PF eye drops (p<0.001). Conclusions: Symptoms and signs are less prevalent when PF drops are used. Moreover, most of the adverse reactions induced by P glaucoma medication are reversible after removing preservatives. PMID:11914211

DNA commission of the International Society of Forensic Genetics: Recommendations on the evaluation of STR typing results that may include drop-out and/or drop-in using probabilistic methods

PubMed Central

Gill, P.; Gusmão, L.; Haned, H.; Mayr, W.R.; Morling, N.; Parson, W.; Prieto, L.; Prinz, M.; Schneider, H.; Schneider, P.M.; Weir, B.S.

2015-01-01

DNA profiling of biological material from scenes of crimes is often complicated because the amount of DNA is limited and the quality of the DNA may be compromised. Furthermore, the sensitivity of STR typing kits has been continuously improved to detect low level DNA traces. This may lead to (1) partial DNA profiles and (2) detection of additional alleles. There are two key phenomena to consider: allelic or locus ‘drop-out’, i.e. ‘missing’ alleles at one or more genetic loci, while ‘drop-in’ may explain alleles in the DNA profile that are additional to the assumed main contributor(s). The drop-in phenomenon is restricted to 1 or 2 alleles per profile. If multiple alleles are observed at more than two loci then these are considered as alleles from an extra contributor and analysis can proceed as a mixture of two or more contributors. Here, we give recommendations on how to estimate probabilities considering drop-out, Pr(D), and drop-in, Pr(C). For reasons of clarity, we have deliberately restricted the current recommendations considering drop-out and/or drop-in at only one locus. Furthermore, we offer recommendations on how to use Pr(D) and Pr(C) with the likelihood ratio principles that are generally recommended by the International Society of Forensic Genetics (ISFG) as measure of the weight of the evidence in forensic genetics. Examples of calculations are included. An Excel spreadsheet is provided so that scientists and laboratories may explore the models and input their own data. PMID:22864188

Analysis of preparation of Chinese traditional medicine based on the fiber fingerprint drop trace

NASA Astrophysics Data System (ADS)

Zhang, Zhilin; Wang, Jialu; Sun, Weimin; Yan, Qi

2010-11-01

The purpose of the fiber micro-drop analyzing technique is to measure the characteristics of liquids using optical methods. The fiber fingerprint drop trace (FFDT) is a curve of light intensity vs. time. This curve indicates the forming, growing and dripping processes of the liquid drops. A pair of fibers was used to monitor the dripping process. The FFDTs are acquired and analyzed by a computer. Different liquid samples of many kinds of preparation of Chinese traditional medicines were tested by using the fiber micro-drop sensor in the experiments. The FFDTs of preparation of Chinese traditional medicines with different concentrations were analyzed in different ways. Considering the characters of the FFDTs, a novel method is proposed to measure the different preparation of Chinese traditional medicines and its concentration based on the corresponding relationship of FFDTs and the physical and chemical parameters of the liquids.

Results of a Multicenter, Randomized, Double-Masked, Placebo-Controlled Clinical Study of the Efficacy and Safety of Visomitin Eye Drops in Patients with Dry Eye Syndrome.

PubMed

Brzheskiy, Vladimir V; Efimova, Elena L; Vorontsova, Tatiana N; Alekseev, Vladimir N; Gusarevich, Olga G; Shaidurova, Ksenia N; Ryabtseva, Alla A; Andryukhina, Olga M; Kamenskikh, Tatiana G; Sumarokova, Elena S; Miljudin, Eugeny S; Egorov, Eugeny A; Lebedev, Oleg I; Surov, Alexander V; Korol, Andrii R; Nasinnyk, Illia O; Bezditko, Pavel A; Muzhychuk, Olena P; Vygodin, Vladimir A; Yani, Elena V; Savchenko, Alla Y; Karger, Elena M; Fedorkin, Oleg N; Mironov, Alexander N; Ostapenko, Victoria; Popeko, Natalia A; Skulachev, Vladimir P; Skulachev, Maxim V

2015-12-01

This article presents the results of an international, multicenter, randomized, double-masked, placebo-controlled clinical study of Visomitin (Mitotech LLC, Moscow, Russian Federation) eye drops in patients with dry eye syndrome (DES). Visomitin is the first registered (in Russia) drug with a mitochondria-targeted antioxidant (SkQ1) as the active ingredient. In this multicenter (10 sites) study of 240 subjects with DES, study drug (Visomitin or placebo) was self-administered three times daily (TID) for 6 weeks, followed by a 6-week follow-up period. Seven in-office study visits occurred every 2 weeks during both the treatment and follow-up periods. Efficacy measures included Schirmer's test, tear break-up time, fluorescein staining, meniscus height, and visual acuity. Safety measures included adverse events, slit lamp biomicroscopy, tonometry, blood pressure, and heart rate. Tolerability was also evaluated. This clinical study showed the effectiveness of Visomitin eye drops in the treatment of signs and symptoms of DES compared with placebo. The study showed that a 6-week course of TID topical instillation of Visomitin significantly improved the functional state of the cornea; Visomitin increased tear film stability and reduced corneal damage. Significant reduction of dry eye symptoms (such as dryness, burning, grittiness, and blurred vision) was also observed. Based on the results of this study, Visomitin is effective and safe for use in eye patients with DES for protection from corneal damage. Mitotech LLC.

Kinematic And Neuromuscular Measures Of Intensity During Plyometric Jumps.

PubMed

Andrade, David Cristóbal; Manzo, Oscar; Beltrán, Ana Rosa; Álvarez, Cristian; Del Rio, Rodrigo; Toledo, Camilo; Moran, Jason; Ramirez-Campillo, Rodrigo

2017-08-15

The aim of this study was to assess jumping performance and neuromuscular activity in lower limb muscles after drop jumps (DJ) from different drop heights (intensity) and during continuous jumping (fatigue), using markers such as reactive strength, jump height, mechanical power and surface electromyography (sEMG). The eccentric (EC) and concentric (CON) sEMG from the medial gastrocnemius (MG), biceps femoris (BF) and rectus (R) muscles were assessed during all tests. In a cross-sectional, randomized study, eleven volleyball players (age 24.4±3.2 years) completed 20 to 90-cm (DJ20 to DJ90) drop jumps and a 60-s continuous jump test. A one-way ANOVA test was used for comparisons, with Sidak post-hoc. The α level was <0.05. Reactive strength was greater for DJ40 compared to DJ90 (p<0.05; ES: 1.27). Additionally jump height was greater for DJ40 and DJ60 compared to DJ20 (p<0.05; ES: 1.26 and 1.27, respectively). No clear pattern of neuromuscular activity appeared during DJ20 to DJ90: some muscles showed greater, lower, or no change with increasing heights for both agonist and antagonist muscles, as well as for eccentric and concentric activity. Mechanical power, but not reactive strength, was reduced in the 60-s jump test (p<0.05; ES: 3.46). No changes were observed in sEMG for any muscle during the eccentric phase nor for the R muscle during the concentric phase of the 60-s jump test. However, for both MG and BF, concentric sEMG was reduced during the 60-s jump test (p<0.05; ES: 5.10 and 4.61, respectively). In conclusion, jumping performance and neuromuscular markers are sensitive to DJ height (intensity), although not in a clear dose-response fashion. In addition, markers such as mechanical power and sEMG are especially sensitive to the effects of continuous jumping (fatigue). Therefore, increasing the drop height during DJ does not ensure a greater training intensity and a combination of different drop heights may be required to elicit adaptations.

"Feminine Protection": The Effects of Menstruation on Attitudes towards Women

ERIC Educational Resources Information Center

Roberts, Tomi-Ann; Goldenberg, Jamie L.; Power, Cathleen; Pyszczynski, Tom

2002-01-01

An experiment tested the hypothesis that reminders of a woman's menstrual status lead to more negative reactions to her and increased objectification of women in general. Participants interacted with a female confederate who ostensibly accidentally dropped either a tampon or hair clip out of her handbag. Dropping the tampon led to lower…

THE INFLUENCE OF X-RAYS ON THE AGGLUTINATION REACTION IN ANIMALS VACCINATED AGAINST BRUCELLOSIS (in Russian)

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

Zhidovtsev, V.M.

1961-08-01

Tests on rabbits immunized with dry. live brucellosis vaccine and irradiated with 100, 200, and 400 r at the height of agglutination showed a drop in agglutin titer with increased x-ray dose. The higher the dose the faster is the drop n agglutin. (R.V.J.)

Comparison of Drop and Wind-Tunnel Experiments on Bomb Drag at High Subsonic Speeds

NASA Technical Reports Server (NTRS)

Gothert, B.

1948-01-01

The drag coefficients of bombs at high velocities velocity of fall was 97 percent of the speed of sound) (the highest are determined by drop tests and compared with measurements taken in the DVL high-speed closed wind tunnel and the open jet at AVA - Gottingen.

Forward Bay Cover Separation Modeling and Testing for the Orion Multi-Purpose Crew Vehicle

NASA Technical Reports Server (NTRS)

Ali, Yasmin; Radke, Tara; Chuhta, Jesse; Hughes, Michael

2014-01-01

Spacecraft multi-body separation events during atmospheric descent require complex testing and analysis to validate the flight separation dynamics model and to verify no recontact. NASA Orion Multi-Purpose Crew Vehicle (MPCV) teams examined key model parameters and risk areas to develop a robust but affordable test campaign in order to validate and verify the Forward Bay Cover (FBC) separation event for Exploration Flight Test-1 (EFT-1). The FBC jettison simulation model is highly complex, consisting of dozens of parameters varied simultaneously, with numerous multi-parameter interactions (coupling and feedback) among the various model elements, and encompassing distinct near-field, mid-field, and far-field regimes. The test campaign was composed of component-level testing (for example gas-piston thrusters and parachute mortars), ground FBC jettison tests, and FBC jettison air-drop tests that were accomplished by a highly multi-disciplinary team. Three ground jettison tests isolated the testing of mechanisms and structures to anchor the simulation models excluding aerodynamic effects. Subsequently, two air-drop tests added aerodynamic and parachute parameters, and served as integrated system demonstrations, which had been preliminarily explored during the Orion Pad Abort-1 (PA-1) flight test in May 2010. Both ground and drop tests provided extensive data to validate analytical models and to verify the FBC jettison event for EFT-1, but more testing is required to support human certification, for which NASA and Lockheed Martin are applying knowledge from Apollo and EFT-1 testing and modeling to develop a robust but affordable human spacecraft capability.

Structural testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container

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

Bronowski, D.R.; Madsen, M.M.

The Heat Source/Radioisotopic Thermoelectric Generator shipping container is a Type B packaging design currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to the normal and hypothetical accident environments defined in Title 10 Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this package design. This report documents the test program portion of the design verification, using several prototype packages. Four types of testing were performed: 30-foot hypothetical accident condition drop tests in threemore » orientations, 40-inch hypothetical accident condition puncture tests in five orientations, a 21 psi external overpressure test, and a normal conditions of transport test consisting of a water spray and a 4 foot drop test. 18 refs., 104 figs., 13 tabs.« less

Filter aids influence on pressure drop across a filtration system

NASA Astrophysics Data System (ADS)

Hajar, S.; Rashid, M.; Nurnadia, A.; Ammar, M. R.; Hasfalina, C. M.

2017-06-01

Filter aids is commonly used to reduce pressure drop across air filtration system as it helps to increase the efficiency of filtration of accumulated filter cake. Filtration velocity is one of the main parameters that affect the performance of filter aids material. In this study, a formulated filter aids consisting of PreKot™ and activated carbon mixture (designated as PrekotAC) was tested on PTFE filter media under various filtration velocities of 5, 6, and 8 m/min at a constant material loading of 0.2 mg/mm2. Results showed that pressure drop is highly influenced by filtration velocity where higher filtration velocity leads to a higher pressure drop across the filter cake. It was found that PrekotAC performed better in terms of reducing the pressure drop across the filter cake even at the highest filtration velocity. The diversity in different particle size distribution of non-uniform particle size in the formulated PrekotAC mixture presents a higher permeability causes a lower pressure drop across the accumulated filter cake. The finding suggests that PrekotAC is a promising filter aids material that helps reducing the pressure drop across fabric filtration system.

Bubble, Drop and Particle Unit (BDPU)

NASA Technical Reports Server (NTRS)

1998-01-01

This section of the Life and Microgravity Spacelab (LMS) publication includes the following articles entitled: (1) Oscillatory Thermocapillary Instability; (2) Thermocapillary Convection in Multilayer Systems; (3) Bubble and Drop Interaction with Solidification Front; (4) A Liquid Electrohydrodynamics Experiment; (5) Boiling on Small Plate Heaters under Microgravity and a Comparison with Earth Gravity; (6) Thermocapillary Migration and Interactions of Bubbles and Drops; and (7) Nonlinear Surface Tension Driven Bubble Migration

Undercooling of acoustically levitated molten drops

NASA Technical Reports Server (NTRS)

Ohsaka, K.; Trinh, E. H.; Glicksman, M. E.

1990-01-01

It was observed that the acoustically levitated molten SCN (succinonitrile) drops can generally be undercooled to a degree where the impurities in the drop are responsible for the nucleation of the solid phase. However, it was also observed that ultrasound occasionally terminates undercooling of the levitated drops by initiating the nucleation of the solid at an undercooling level which is lower than that found for the nucleation catalyzed by the impurities in the drop. This premature nucleation can be explained by thermodynamic considerations which predict an increase in effective undercooling of the liquid upon the collapse of cavities. Pre-existing gas microbubbles which grow under the influence of ultrasound are suggested as the source of cavitation. The highly undercooled SCN drops can be utilized to measure the growth velocity of the solid in the deeply undercooled region including the hypercooled region.

Novel Process for Removal and Recovery of Vapor Phase Mercury

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

Greenwell, Collin; Roberts, Daryl L; Albiston, Jason

We demonstrated in the Phase I program all key attributes of a new technology for removing mercury from flue gases, namely, a) removal of greater than 95% of both elemental and oxidized forms of mercury, both in the laboratory and in the field b) regenerability of the sorbent c) ability to scale up, and d) favorable economics. The Phase I program consisted of four tasks other than project reporting: Task I-1 Screen Sorbent Configurations in the Laboratory Task I-2 Design and Fabricate Bench-Scale Equipment Task I-3 Test Bench-Scale Equipment on Pilot Combustor Task I-4 Evaluate Economics Based on Bench-Scale Resultsmore » In Task I-1, we demonstrated that the sorbents are thermally durable and are regenerable through at least 55 cycles of mercury uptake and desorption. We also demonstrated two low-pressure- drop configurations of the sorbent, namely, a particulate form and a monolithic form. We showed that the particulate form of the sorbent would take up 100% of the mercury so long as the residence time in a bed of the sorbent exceeded 0.1 seconds. In principle, the particulate form of the sorbent could be imbedded in the back side of a higher temperature bag filter in a full-scale application. With typical bag face velocities of four feet per minute, the thickness of the particulate layer would need to be about 2000 microns to accomplish the uptake of the mercury. For heat transfer efficiency, however, we believed the monolithic form of the sorbent would be the more practical in a full scale application. Therefore, we purchased commercially-available metallic monoliths and applied the sorbent to the inside of the flow channels of the monoliths. At face velocities we tested (up to 1.5 ft/sec), these monoliths had less than 0.05 inches of water pressure drop. We tested the monolithic form of the sorbent through 21 cycles of mercury sorption and desorption in the laboratory and included a test of simultaneous uptake of both mercury and mercuric chloride. Overall, in Task I-1, we found that the particulate and monolith forms of the sorbent were thermally stable and durable and would repeatedly sorb and desorb 100% of the mercury, including mercuric chloride, with low pressure drop and short residence times at realistic flue gas conditions.« less

The effect of temperature, matrix alloying and substrate coatings on wettability and shear strength of Al/Al2O3 couples

NASA Astrophysics Data System (ADS)

Sobczak, N.; Ksiazek, M.; Radziwill, W.; Asthana, R.; Mikulowski, B.

2004-03-01

A fresh approach has been advanced to examine in the Al/Al2O3 system the effects of temperature, alloying of Al with Ti or Sn, and Ti and Sn coatings on the substrate, on contact angles measured using a sessile-drop test, and on interface strength measured using a modified push-off test that allows shearing of solidified droplets with less than 90 deg contact angle. In the modified test, the solidified sessile-drop samples are bisected perpendicular to the drop/Al2O3 interface at the midplane of the contact circle to obtain samples that permit bond strength measurement by stress application to the flat surface of the bisected couple. The test results show that interface strength is strongly influenced by the wetting properties; low contact angles correspond to high interface strength, which also exhibits a strong temperature dependence. An increase in the wettability test temperature led to an increase in the interface strength in the low-temperature range where contact angles were large and wettability was poor. The room-temperature shear tests conducted on thermally cycled sessile-drop test specimens revealed the effect of chemically formed interfacial oxides; a weakening of the thermally cycled Al/Al2O3 interface was caused under the following conditions: (1) slow contact heating and short contact times in the wettability test, and (2) fast contact heating and longer contact times. The addition of 6 wt pct Ti or 7 wt pct Sn to Al only marginally influenced the contact angle and interfacial shear strength. However, Al2O3 substrates having thin (<1 µm) Ti coatings yielded relatively low contact angles and high bond strength, which appears to be related to the dissolution of the coating in Al and formation of a favorable interface structure.

Investigating performance of microchannel evaporators for automobile air conditioning with different port structures

NASA Astrophysics Data System (ADS)

Zhou, Guoliang; Su, Lin; Cheng, Qia; Wu, Longbing

2017-08-01

Microchannel evaporator has been widely applied in automobile air conditioning, while it faces the problem of refrigerant maldistribution which deteriorates the thermal performance of evaporator. In this study, the performances of microchannel evaporators with different port structures are experimentally investigated for purpose of reducing evaporator pressure drop. Four evaporator samples with different port number and hydraulic diameter are made for this study. The performances of the evaporator samples are tested on a psychometric calorimeter test bench with the refrigerant R-134A at a real automobile air conditioning. The results on the variations of the evaporator pressure drop and evaporator surface temperature distribution are presented and analyzed. By studying the performance of an evaporator, seeking proper port structure is an approach to reduce refrigerant pressure drop as well as improve refrigerant distribution.

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.

Water Pump Development for the EVA PLSS

NASA Technical Reports Server (NTRS)

Schuller, Michael; Kurwitz, Cable; Goldman, Jeff; Morris, Kim; Trevino, Luis

2009-01-01

This paper describes the effort by the Texas Engineering Experiment Station (TEES) and Honeywell for NASA to design, fabricate, and test a preflight prototype pump for use in the Extravehicular activity (EVA) portable life support subsystem (PLSS). Major design decisions were driven by the need to reduce the pump s mass, power, and volume compared to the existing PLSS pump. In addition, the pump will accommodate a much wider range of abnormal conditions than the existing pump, including vapor/gas bubbles and increased pressure drop when employed to cool two suits simultaneously. A positive displacement, external gear type pump was selected because it offers the most compact and highest efficiency solution over the required range of flow rates and pressure drops. An additional benefit of selecting a gear pump design is that it is self priming and capable of ingesting noncondensable gas without becoming "air locked." The chosen pump design consists of a 28 V DC, brushless, sealless, permanent magnet motor driven, external gear pump that utilizes a Honeywell development that eliminates the need for magnetic coupling. Although the planned flight unit will use a sensorless motor with custom designed controller, the preflight prototype to be provided for this project incorporates Hall effect sensors, allowing an interface with a readily available commercial motor controller. This design approach reduced the cost of this project and gives NASA more flexibility in future PLSS laboratory testing. The pump design was based on existing Honeywell designs, but incorporated features specifically for the PLSS application, including all of the key features of the flight pump. Testing at TEES will simulate the vacuum environment in which the flight pump will operate. Testing will verify that the pump meets design requirements for range of flow rates, pressure rise, power consumption, working fluid temperature, operating time, and restart capability. Pump testing is currently scheduled for March, 2009, after which the pump will be delivered to NASA for further testing.

Control group design, contamination and drop-out in exercise oncology trials: a systematic review.

PubMed

Steins Bisschop, Charlotte N; Courneya, Kerry S; Velthuis, Miranda J; Monninkhof, Evelyn M; Jones, Lee W; Friedenreich, Christine; van der Wall, Elsken; Peeters, Petra H M; May, Anne M

2015-01-01

Important considerations for exercise trials in cancer patients are contamination and differential drop-out among the control group members that might jeopardize the internal validity. This systematic review provides an overview of different control groups design characteristics of exercise-oncology trials and explores the association with contamination and drop-out rates. Randomized controlled exercise-oncology trials from two Cochrane reviews were included. Additionally, a computer-aided search using Medline (Pubmed), Embase and CINAHL was conducted after completion date of the Cochrane reviews. Eligible studies were classified according to three control group design characteristics: the exercise instruction given to controls before start of the study (exercise allowed or not); and the intervention the control group was offered during (any (e.g., education sessions or telephone contacts) or none) or after (any (e.g., cross-over or exercise instruction) or none) the intervention period. Contamination (yes or no) and excess drop-out rates (i.e., drop-out rate of the control group minus the drop-out rate exercise group) were described according to the three design characteristics of the control group and according to the combinations of these three characteristics; so we additionally made subgroups based on combinations of type and timing of instructions received. 40 exercise-oncology trials were included based on pre-specified eligibility criteria. The lowest contamination (7.1% of studies) and low drop-out rates (excess drop-out rate -4.7±9.2) were found in control groups offered an intervention after the intervention period. When control groups were offered an intervention both during and after the intervention period, contamination (0%) and excess drop-out rates (-10.0±12.8%) were even lower. Control groups receiving an intervention during and after the study intervention period have lower contamination and drop-out rates. The present findings can be considered when designing future exercise-oncology trials.

Irreversible Entropy Production in Two-Phase Mixing Layers

NASA Technical Reports Server (NTRS)

Okongo, Nora

2003-01-01

This report presents a study of dissipation (irreversible production of entropy) in three-dimensional, temporal mixing layers laden with evaporating liquid drops. The purpose of the study is to examine the effects of evaporating drops on the development of turbulent features in flows. Direct numerical simulations were performed to analyze transitional states of three mixing layers: one without drops, and two that included drops at different initial mass loadings. Without drops, the dissipation is essentially due to viscous effects. It was found that in the presence of drops, the largest contribution to dissipation was made by heating and evaporation of the drops, and that at large length scales, this contribution is positive (signifying that the drops reduce turbulence), while at small scales, this contribution is negative (the drops increase turbulence). The second largest contribution to dissipation was found to be associated with the chemical potential, which leads to an increase in turbulence at large scales and a decrease in turbulence at small scales. The next smaller contribution was found to be that of viscosity. The fact that viscosity effects are only third in order of magnitude in the dissipation is in sharp contrast to the situation for the mixing layer without the drops. The next smaller contribution - that of the drag and momentum of the vapor from the drops - was found to be negative at lower mass loading but to become positive at higher mass loading.

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

PubMed

Xie, Chiyu; Liu, Guangzhi; Wang, Moran

2016-08-16

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

Wetting-induced formation of controllable monodisperse multiple emulsions in microfluidics.

PubMed

Deng, Nan-Nan; Wang, Wei; Ju, Xiao-Jie; Xie, Rui; Weitz, David A; Chu, Liang-Yin

2013-10-21

Multiple emulsions, which are widely applied in a myriad of fields because of their unique ability to encapsulate and protect active ingredients, are typically produced by sequential drop-formations and drop-encapsulations using shear-induced emulsification. Here we report a qualitatively novel method of creating highly controlled multiple emulsions from lower-order emulsions. By carefully controlling the interfacial energies, we adjust the spreading coefficients between different phases to cause drops of one fluid to completely engulf other drops of immiscible fluids; as a result multiple emulsions are directly formed by simply putting preformed lower-order emulsion drops together. Our approach has highly controllable flexibility. We demonstrate this in preparation of both double and triple emulsions with a controlled number of inner drops and precisely adjusted shell thicknesses including ultra-thin shells. Moreover, this controllable drop-engulfing-drop approach has a high potential in further investigations and applications of microfluidics. Importantly, this innovative approach opens a window to exploit new phenomena occurring in fluids at the microscale level, which is of great significance for developing novel microfluidics.

14 CFR 29.307 - Proof of structure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... loading condition accounting for the environment to which the structure will be exposed in operation... measurement tests; (5) Landing gear drop tests; and (6) Any additional tests required for new or unusual...

Evaluation of lower leg function in patients with Achilles tendinopathy.

PubMed

Silbernagel, Karin Grävare; Gustavsson, Alexander; Thomeé, Roland; Karlsson, Jon

2006-11-01

Achilles tendinopathy is considered to be one of the most common overuse injuries in elite and recreational athletes. However, the effect that the Achilles tendinopathy has on patients' physical performance is still unclear. The purpose of this study was to evaluate if Achilles tendinopathy caused functional deficits on the injured side compared with the non-injured side in patients. A test battery comprised of tests for different aspects of muscle-tendon function of the gastrocnemius, soleus and Achilles tendon complex was developed to evaluate lower leg function. The test battery's test-retest reliability and sensitivity (the percent probability that the tests would demonstrate abnormal lower limb symmetry index in patients) were also evaluated. The test battery consisted of three jump tests, a counter movements jump (CMJ), a drop counter movement jump (drop CMJ) and hopping, and two strength tests, concentric toe-raises, eccentric-concentric toe-raises and toe-raises for endurance. The reliability was evaluated through a test-retest design on 15 healthy subjects. The test battery's sensitivity and possible functional deficits in patients with Achilles tendinopathy were evaluated on 42 patients (19 women and 23 men). An excellent reliability was found between test days 1-2 and 2-3 for all tests (ICC = 0.76-0.94) except for concentric toe-raise, test 2-3, which had fair reliability (ICC = 0.73). The methodological error ranged from 8 to 17%. There were significant differences (P = 0.001-0.049) between the non-injured (or least symptomatic) side and injured (most symptomatic) side for hopping, drop CMJ, concentric and eccentric-concentric toe-raises, and significant differences (P = 0.000-0.012) in the level of pain during CMJ, hopping, and drop CMJ. The sensitivity of the test battery at a 90% capacity was 88. Achilles tendinopathy causes not only pain and symptoms in patients but also apparent impairments in various aspects of lower leg muscle-tendon function as measured with the test battery. This test battery is reliable and able to detect differences in lower leg function between the injured or "most symptomatic" and non-injured or "least symptomatic" side in patients with Achilles tendinopathy. The test battery has higher demand on patients' function compared with each individual test.

Effects of Auroral Potential Drops on Field-Aligned Currents and Nightside Reconnection Dynamos

NASA Astrophysics Data System (ADS)

Lotko, W.; Xi, S.; Zhang, B.; Wiltberger, M. J.; Lyon, J.

2016-12-01

The reaction of the magnetosphere-ionosphere system to dynamic auroral potential drops is investigated using the Lyon-Fedder-Mobarry global model and, for the first time in a global simulation, including the dissipative load of field-aligned potential drops in the low-altitude boundary condition. This extra load reduces the demand for field-aligned current (j||) from nightside reconnection dynamos. The system adapts by forcing the nightside x-line closer to Earth to reduce current lensing (j||/B = constant) at the ionosphere, with the plasma sheet undergoing additional contraction during substorm recovery and steady magnetospheric convection. For steady and moderate solar wind driving and with constant ionospheric conductance, the cross-polar cap potential and hemispheric field-aligned current are lower by approximately the ratio of the peak field-aligned potential drop to the cross polar cap potential (10-15%) when potential drops are included. Hemispheric ionospheric Joule dissipation is less by 8%, while the area-integrated, average work done on the fluid by the reconnecting magnetotail field increases by 50% within |y| < 8 RE. Effects on the nightside plasma sheet include: (1) an average x-line 4 RE closer to Earth; (2) a 12% higher mean reconnection rate; and (3) dawn-dusk asymmetry in reconnection with a 17% higher rate in the premidnight sector.

Effects of auroral potential drops on plasma sheet dynamics

NASA Astrophysics Data System (ADS)

Xi, Sheng; Lotko, William; Zhang, Binzheng; Wiltberger, Michael; Lyon, John

2016-11-01

The reaction of the magnetosphere-ionosphere system to dynamic auroral potential drops is investigated using the Lyon-Fedder-Mobarry global model including, for the first time in a global simulation, the dissipative load of field-aligned potential drops in the low-altitude boundary condition. This extra load reduces the field-aligned current (j||) supplied by nightside reconnection dynamos. The system adapts by forcing the nightside X line closer to Earth, with a corresponding reduction in current lensing (j||/B = constant) at the ionosphere and additional contraction of the plasma sheet during substorm recovery and steady magnetospheric convection. For steady and moderate solar wind driving and with constant ionospheric conductance, the cross polar cap potential and hemispheric field-aligned current are lower by approximately the ratio of the peak field-aligned potential drop to the cross polar cap potential (10-15%) when potential drops are included. Hemispheric ionospheric Joule dissipation is less by 8%, while the area-integrated, average work done on the fluid by the reconnecting magnetotail field increases by 50% within |y| < 8 RE. Effects on the nightside plasma sheet include (1) an average X line 4 RE closer to Earth; (2) a 12% higher mean reconnection rate; and (3) dawn-dusk asymmetry in reconnection with a 17% higher rate in the premidnight sector.

Spectrometer system for optical reflectance measurements

NASA Technical Reports Server (NTRS)

Phillipps, Patrick G. (Inventor); Soller, Babs R. (Inventor); Parker, Michael S. (Inventor)

2007-01-01

A spectrometer system includes a thermal light source for illuminating a sample, where the thermal light source includes a filament that emits light when heated. The system additionally includes a spectrograph for measuring a light spectrum from the sample and an electrical circuit for supplying electrical current to the filament to heat the filament and for controlling a resistance of the filament. The electrical circuit includes a power supply that supplies current to the filament, first electrical components that sense a current through the filament, second electrical components that sense a voltage drop across the filament, third electrical components that compare a ratio of the sensed voltage drop and the sensed current with a predetermined value, and fourth electrical components that control the current through the filament or the voltage drop across the filament to cause the ratio to equal substantially the predetermined value.

Measuring the Densities of Aqueous Glasses at Cryogenic Temperatures.

PubMed

Shen, Chen; Julius, Ethan F; Tyree, Timothy J; Dan, Ritwik; Moreau, David W; Thorne, Robert

2017-06-28

We demonstrate a method for determining the vitreous phase cryogenic temperature densities of aqueous mixtures, and other samples that require rapid cooling, to prepare the desired cryogenic temperature phase. Microliter to picoliter size drops are cooled by projection into a liquid nitrogen-argon (N2-Ar) mixture. The cryogenic temperature phase of the drop is evaluated using a visual assay that correlates with X-ray diffraction measurements. The density of the liquid N2-Ar mixture is adjusted by adding N2 or Ar until the drop becomes neutrally buoyant. The density of this mixture and thus of the drop is determined using a test mass and Archimedes principle. With appropriate care in drop preparation, management of gas above the liquid cryogen mixture to minimize icing, and regular mixing of the cryogenic mixture to prevent density stratification and phase separation, densities accurate to <0.5% of drops as small as 50 pL can readily be determined. Measurements on aqueous cryoprotectant mixtures provide insight into cryoprotectant action, and provide quantitative data to facilitate thermal contraction matching in biological cryopreservation.

14 CFR 27.307 - Proof of structure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... loading condition accounting for the environment to which the structure will be exposed in operation... measurement tests; (5) Landing gear drop tests; and (6) Any additional test required for new or unusual design...

Validation of an Active Gear, Flexible Aircraft Take-off and Landing analysis (AGFATL)

NASA Technical Reports Server (NTRS)

Mcgehee, J. R.

1984-01-01

The results of an analytical investigation using a computer program for active gear, flexible aircraft take off and landing analysis (AGFATL) are compared with experimental data from shaker tests, drop tests, and simulated landing tests to validate the AGFATL computer program. Comparison of experimental and analytical responses for both passive and active gears indicates good agreement for shaker tests and drop tests. For the simulated landing tests, the passive and active gears were influenced by large strut binding friction forces. The inclusion of these undefined forces in the analytical simulations was difficult, and consequently only fair to good agreement was obtained. An assessment of the results from the investigation indicates that the AGFATL computer program is a valid tool for the study and initial design of series hydraulic active control landing gear systems.

Reaching Graduation with Credit Recovery

ERIC Educational Resources Information Center

Dessoff, Alan

2009-01-01

When students fail courses or drop out of school, it isn't good for them or their districts, which are under federal and state mandates to improve test scores and graduation rates. With those mandates and about 1.2 million students dropping out each year--or one every 26 seconds--there is more pressure today than ever to help students stay in…

Predictors of Weapon Carrying in Youth Attending Drop-in Centers

ERIC Educational Resources Information Center

Blumberg, Elaine J.; Liles, Sandy; Kelley, Norma J.; Hovell, Melbourne F.; Bousman, Chad A.; Shillington, Audrey M.; Ji, Ming; Clapp, John

2009-01-01

Objective: To test and compare 2 predictive models of weapon carrying in youth (n=308) recruited from 4 drop-in centers in San Diego and Imperial counties. Methods: Both models were based on the Behavioral Ecological Model (BEM). Results: The first and second models significantly explained 39% and 53% of the variance in weapon carrying,…

The Scholar Identity Institute: Guiding Darnel and Other Black Males

ERIC Educational Resources Information Center

Whiting, Gilman W.

2009-01-01

Despite the major push for higher student outcomes in graduation, school achievement, and test scores, even when legislated (NCLB, 2001), too many students fail to persist in school, often choosing to drop out as their last resort (Bridgeland, DiIulio, & Morison, 2006). Specifically, one third of the nation's students drop out of school, even when…

Japanese supply ship delivers to space station on This Week @NASA – August 28, 2015

NASA Image and Video Library

2015-08-28

It was a busy week for the crew aboard the International Space Station. The Japanese Aerospace Exploration Agency’s fifth H-II Transfer Vehicle, or HTV-5 arrived on Aug. 24 with more than 8,000 pounds of equipment, supplies and experiments in its pressurized cargo compartment. The delivery included an investigation that will search for signatures of dark matter, as well as enough additional food and supplies to last through 2015. Also, Soyuz relocated to Zvezda, Orion parachute drop test, Rising Seas, Hurricane Katrina remembrance, Tail first crash test, Webb telescope’s backplane arrives and Hubble’s double black hole!

Analysis of Skylab IV fluid mechanic science demonstration

NASA Technical Reports Server (NTRS)

Klett, M. G.; Bourgeois, S. V.

1975-01-01

Several science demonstrations performed on Skylab III and IV were concerned with the behavior of fluid drops free floating in microgravity. These demonstrations, with large liquid drops, included the oscillation, rotation, impact and coalescence, and air injection into the drops. Rayleigh's analysis of the oscillation of spherical drops of a liquid predicts accurately the effect of size and surface tension on the frequency of vibrated water globules in the Skylab demonstration. However, damping occurred much faster than predicted by Lamb's or Scriven's analyses of the damping time for spherical drops. The impact demonstrations indicated that a minimum velocity is necessary to overcome surface forces and effect a coalescence, but a precise criterion for the coalescence of liquids in low g could not be determined.

Evaluation of Two Crew Module Boilerplate Tests Using Newly Developed Calibration Metrics

NASA Technical Reports Server (NTRS)

Horta, Lucas G.; Reaves, Mercedes C.

2012-01-01

The paper discusses a application of multi-dimensional calibration metrics to evaluate pressure data from water drop tests of the Max Launch Abort System (MLAS) crew module boilerplate. Specifically, three metrics are discussed: 1) a metric to assess the probability of enveloping the measured data with the model, 2) a multi-dimensional orthogonality metric to assess model adequacy between test and analysis, and 3) a prediction error metric to conduct sensor placement to minimize pressure prediction errors. Data from similar (nearly repeated) capsule drop tests shows significant variability in the measured pressure responses. When compared to expected variability using model predictions, it is demonstrated that the measured variability cannot be explained by the model under the current uncertainty assumptions.

Temperature-mediated absorption of phenylmercuric nitrate on polyethylene and polypropylene containers in chloramphenicol eye drops.

PubMed

Charoo, Naseem; Chiew, Magdalene; Tay, Amelia; Lian, Lai

2014-09-01

The aim of this work was to find the effect of temperature and manufacturing source of phenylmercuric nitrate (PMN) on PMN absorption on low-density polyethylene (LDPE) and polypropylene containers in chloramphenicol eye drops. Two factorial experiments were designed to study the effect of temperature on PMN assay in chloramphenicol eye drops stored in LDPE and prepared from two different PMN sources. PMN source had no effect on PMN assay at 2-8 °C, however at stress conditions (30 °C/75%RH) for 3 weeks, the effect of PMN source on PMN assay was found significant (p < 0.05) in formulations stored in LDPE bottles. Temperature was the major contributor to decreased PMN assay. In formulations stored in polypropylene containers, PMN source had significant effect on PMN assay at 2-8 °C and 30 °C/75%RH. Overall, new PMN and polypropylene bottles performed better. The eye drops complied with preservative efficacy test both initially and at the end of shelf life. The concentration exponent of PMN is very low and in spite of its high absorption by container/closure, PMN was still able to protect the eye drops at the end of shelf life. It can be inferred that preservative efficacy test is the better indicator of preservative activity.

Prediction of orthostatic hypotension in multiple system atrophy and Parkinson disease

PubMed Central

Sun, Zhanfang; Jia, Dandan; Shi, Yuting; Hou, Xuan; Yang, Xiaosu; Guo, Jifeng; Li, Nan; Wang, Junling; Sun, Qiying; Zhang, Hainan; Lei, Lifang; Shen, Lu; Yan, Xinxiang; Xia, Kun; Jiang, Hong; Tang, Beisha

2016-01-01

Orthostatic hypotension (OH) is common in multiple system atrophy (MSA) and Parkinson disease (PD), generally assessed through a lying-to-standing orthostatic test. However, standing blood pressure may not be available due to orthostatic intolerance or immobilization for such patients. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were successively measured in supine, sitting, and standing positions in patients with MSA and PD. Receiver operating characteristic analysis was used to evaluate diagnostic performance of the drops of sitting SBP or DBP. OH and severe OH were respectively regarded as “gold standard”. The drops of SBP in standing position were associated with increased disease severity for MSA and correlated with age for PD. In MSA group, drops in sitting SBP ≥ 14 mmHg or DBP ≥ 6 mmHg had highest validity for prediction of OH, and drops in sitting SBP ≥ 18 mmHg or DBP ≥ 8 mmHg for severe OH. In PD group, drops in sitting SBP ≥ 10 mmHg or DBP ≥ 6 mmHg had highest validity for prediction of OH. The lying-to-sitting orthostatic test is an alternative method for detection of OH in MSA and PD, especially when standing BP could not be validly measured due to various reasons. PMID:26867507

Viscosity Measurement Using Drop Coalescence in Microgravity

NASA Technical Reports Server (NTRS)

Antar, Basil N.; Ethridge, Edwin C.; Maxwell, Daniel; Curreri, Peter A. (Technical Monitor)

2002-01-01

We present in here validation studies of a new method for application in microgravity environment which measures the viscosity of highly viscous undercooled liquids using drop coalescence. The method has the advantage of avoiding heterogeneous nucleation at container walls caused by crystallization of undercooled liquids during processing. Homogeneous nucleation can also be avoided due to the rapidity of the measurement using this method. The technique relies on measurements from experiments conducted in near zero gravity environment as well as highly accurate analytical formulation for the coalescence process. The viscosity of the liquid is determined by allowing the computed free surface shape relaxation time to be adjusted in response to the measured free surface velocity for two coalescing drops. Results are presented from two sets of validation experiments for the method which were conducted on board aircraft flying parabolic trajectories. In these tests the viscosity of a highly viscous liquid, namely glycerin, was determined at different temperatures using the drop coalescence method described in here. The experiments measured the free surface velocity of two glycerin drops coalescing under the action of surface tension alone in low gravity environment using high speed photography. The liquid viscosity was determined by adjusting the computed free surface velocity values to the measured experimental data. The results of these experiments were found to agree reasonably well with the known viscosity for the test liquid used.