Testing equivalence of mediating models of income, parenting, and school readiness for white, black, and Hispanic children in a national sample.

PubMed

Raver, C Cybele; Gershoff, Elizabeth T; Aber, J Lawrence

2007-01-01

This paper examines complex models of the associations between family income, material hardship, parenting, and school readiness among White, Black, and Hispanic 6-year-olds, using the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K). It is critical to test the universality of such complex models, particularly given their implications for intervention, prevention, and public policy. Therefore this study asks: Do measures and models of low income and early school readiness indicators fit differently or similarly for White, Black, and Hispanic children? Measurement equivalence of material hardship, parent stress, parenting behaviors, child cognitive skills, and child social competence is first tested. Model equivalence is then tested by examining whether category membership in a race/ethnic group moderates associations between predictors and young children's school readiness.

Testing Equivalence of Mediating Models of Income, Parenting, and School Readiness for White, Black, and Hispanic Children in a National Sample

PubMed Central

Raver, C. Cybele; Gershoff, Elizabeth T.; Aber, J. Lawrence

2010-01-01

This paper examines complex models of the associations between family income, material hardship, parenting, and school readiness among White, Black, and Hispanic 6-year-olds, using the Early Childhood Longitudinal Study – Kindergarten Cohort (ECLS – K). It is critical to test the universality of such complex models, particularly given their implications for intervention, prevention, and public policy. Therefore this study asks: Do measures and models of low income and early school readiness indicators fit differently or similarly for White, Black, and Hispanic children? Measurement equivalence of material hardship, parent stress, parenting behaviors, child cognitive skills, and child social competence is first tested. Model equivalence is then tested by examining whether category membership in a race/ethnic group moderates associations between predictors and young children’s school readiness. PMID:17328695

46 CFR 182.455 - Fuel piping.

Code of Federal Regulations, 2011 CFR

2011-10-01

... piping of other materials, such as seamless steel pipe or tubing, which provide equivalent safety may be... shock. Fuel filters fitted with bowls of other than steel construction must be approved by the Commandant and be protected from mechanical damage. Approval of bowls of other than steel construction will...

46 CFR 182.455 - Fuel piping.

Code of Federal Regulations, 2012 CFR

2012-10-01

... piping of other materials, such as seamless steel pipe or tubing, which provide equivalent safety may be... shock. Fuel filters fitted with bowls of other than steel construction must be approved by the Commandant and be protected from mechanical damage. Approval of bowls of other than steel construction will...

46 CFR 182.455 - Fuel piping.

Code of Federal Regulations, 2013 CFR

2013-10-01

... piping of other materials, such as seamless steel pipe or tubing, which provide equivalent safety may be... shock. Fuel filters fitted with bowls of other than steel construction must be approved by the Commandant and be protected from mechanical damage. Approval of bowls of other than steel construction will...

46 CFR 182.455 - Fuel piping.

Code of Federal Regulations, 2014 CFR

2014-10-01

... piping of other materials, such as seamless steel pipe or tubing, which provide equivalent safety may be... shock. Fuel filters fitted with bowls of other than steel construction must be approved by the Commandant and be protected from mechanical damage. Approval of bowls of other than steel construction will...

46 CFR 132.100 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... equivalent fire-resistant material; and (2) Fitted with a commercial garden-hose nozzle of high-grade bronze..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS FIRE-PROTECTION EQUIPMENT Fire Main § 132... equipped with a fire main that complies with this subpart. (b) Each vessel of less than 100 gross tons and...

30 CFR 250.1002 - Design requirements for DOI pipelines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Design requirements for DOI pipelines. 250.1002 Section 250.1002 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... stresses for pipe of the same or equivalent material. The actual bursting strength of the fitting shall at...

46 CFR 151.55-1 - General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... section provides special requirements for the materials of construction of equipment that may come into..., valves, fittings, and other items of equipment that may come in contact with the cargo liquid or vapor... of equipment that may come in contact with the cargo liquid or vapor. (Equivalent to § 151.56-1(b),(c...

46 CFR 151.55-1 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... section provides special requirements for the materials of construction of equipment that may come into..., valves, fittings, and other items of equipment that may come in contact with the cargo liquid or vapor... of equipment that may come in contact with the cargo liquid or vapor. (Equivalent to § 151.56-1(b),(c...

46 CFR 151.55-1 - General.

Code of Federal Regulations, 2014 CFR

2014-10-01

... section provides special requirements for the materials of construction of equipment that may come into..., valves, fittings, and other items of equipment that may come in contact with the cargo liquid or vapor... of equipment that may come in contact with the cargo liquid or vapor. (Equivalent to § 151.56-1(b),(c...

46 CFR 151.55-1 - General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... section provides special requirements for the materials of construction of equipment that may come into..., valves, fittings, and other items of equipment that may come in contact with the cargo liquid or vapor... of equipment that may come in contact with the cargo liquid or vapor. (Equivalent to § 151.56-1(b),(c...

46 CFR 151.55-1 - General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... section provides special requirements for the materials of construction of equipment that may come into..., valves, fittings, and other items of equipment that may come in contact with the cargo liquid or vapor... of equipment that may come in contact with the cargo liquid or vapor. (Equivalent to § 151.56-1(b),(c...

46 CFR 160.135-7 - Design, construction, and performance of lifeboats.

Code of Federal Regulations, 2013 CFR

2013-10-01

... materials equivalent or superior in strength, design, wet out, and efficiency will be given consideration on.... (8) Starting system batteries. Any battery fitted in a totally enclosed lifeboat must be stored in a... starting battery is required per engine. (9) Exhaust. Engine exhaust must be routed away from bilge and...

46 CFR 160.135-7 - Design, construction, and performance of lifeboats.

Code of Federal Regulations, 2012 CFR

2012-10-01

... materials equivalent or superior in strength, design, wet out, and efficiency will be given consideration on.... (8) Starting system batteries. Any battery fitted in a totally enclosed lifeboat must be stored in a... starting battery is required per engine. (9) Exhaust. Engine exhaust must be routed away from bilge and...

46 CFR 160.135-7 - Design, construction, and performance of lifeboats.

Code of Federal Regulations, 2014 CFR

2014-10-01

... materials equivalent or superior in strength, design, wet out, and efficiency will be given consideration on.... (8) Starting system batteries. Any battery fitted in a totally enclosed lifeboat must be stored in a... starting battery is required per engine. (9) Exhaust. Engine exhaust must be routed away from bilge and...

Design on the wide band absorber with low density based on the particle distribution

NASA Astrophysics Data System (ADS)

Zheng, Dianliang; Liu, Ting; Liu, Longbin; Xu, Yonggang

2018-04-01

In order to widen the absorbing band, an equivalent gradient structure absorber was designed based on the particle distribution. Firstly, the electromagnetic parameter of the absorbent with uniform dispersion was tested using the vector network analyzer in 8-18 GHz. Three different equivalent materials of the spherical, square and hexagon empty shape were designed. The scattering parameters and the monostatic reflection loss (RL) of the periodic structural materials were simulated in the commercial software. Then the effective permittivity and the permeability was derived by the Nicolson-Ross-Weir algorithm and fitted by Maxwell-Garnett mixing rule. The results showed that the simulated reflectance and transmission parameters of equivalent composites with the different shapes were very close. The derived effective permittivity and permeability of the composite with different absorbent content was also close, and the average deviation was about 0.52 + j0.15 and 0.15 + j0.01 respectively. Finally, the wide band absorbing material was designed using the genetic algorithm. The optimized RL result showed that the absorbing composites with thickness 3 mm had an excellent absorbing property (RL <-10 dB) in 8-18 GHz, the equivalent absorber density could be decreased 30.7% compared with the uniform structure.

Mechanistic equivalent circuit modelling of a commercial polymer electrolyte membrane fuel cell

NASA Astrophysics Data System (ADS)

Giner-Sanz, J. J.; Ortega, E. M.; Pérez-Herranz, V.

2018-03-01

Electrochemical impedance spectroscopy (EIS) has been widely used in the fuel cell field since it allows deconvolving the different physic-chemical processes that affect the fuel cell performance. Typically, EIS spectra are modelled using electric equivalent circuits. In this work, EIS spectra of an individual cell of a commercial PEM fuel cell stack were obtained experimentally. The goal was to obtain a mechanistic electric equivalent circuit in order to model the experimental EIS spectra. A mechanistic electric equivalent circuit is a semiempirical modelling technique which is based on obtaining an equivalent circuit that does not only correctly fit the experimental spectra, but which elements have a mechanistic physical meaning. In order to obtain the aforementioned electric equivalent circuit, 12 different models with defined physical meanings were proposed. These equivalent circuits were fitted to the obtained EIS spectra. A 2 step selection process was performed. In the first step, a group of 4 circuits were preselected out of the initial list of 12, based on general fitting indicators as the determination coefficient and the fitted parameter uncertainty. In the second step, one of the 4 preselected circuits was selected on account of the consistency of the fitted parameter values with the physical meaning of each parameter.

Energy absorption buildup factors, exposure buildup factors and Kerma for optically stimulated luminescence materials and their tissue equivalence for radiation dosimetry

NASA Astrophysics Data System (ADS)

Singh, Vishwanath P.; Badiger, N. M.

2014-11-01

Optically stimulated luminescence (OSL) materials are sensitive dosimetric materials used for precise and accurate dose measurement for low-energy ionizing radiation. Low dose measurement capability with improved sensitivity makes these dosimeters very useful for diagnostic imaging, personnel monitoring and environmental radiation dosimetry. Gamma ray energy absorption buildup factors and exposure build factors were computed for OSL materials using the five-parameter Geometric Progression (G-P) fitting method in the energy range 0.015-15 MeV for penetration depths up to 40 mean free path. The computed energy absorption buildup factor and exposure buildup factor values were studied as a function of penetration depth and incident photon energy. Effective atomic numbers and Kerma relative to air of the selected OSL materials and tissue equivalence were computed and compared with that of water, PMMA and ICRU standard tissues. The buildup factors and kerma relative to air were found dependent upon effective atomic numbers. Buildup factors determined in the present work should be useful in radiation dosimetry, medical diagnostics and therapy, space dosimetry, accident dosimetry and personnel monitoring.

Aleatory Uncertainty and Scale Effects in Computational Damage Models for Failure and Fragmentation

DTIC Science & Technology

2014-09-01

larger specimens, small specimens have, on average, higher strengths. Equivalently, because curves for small specimens fall below those of larger...the material strength associated with each realization parameter R in Equation (7), and strength distribution curves associated with multiple...effects in brittle media [58], which applies micromorphological dimensional analysis to obtain a universal curve which closely fits rate-dependent

Attenuation properties of diagnostic x-ray shielding materials.

PubMed

Archer, B R; Fewell, T R; Conway, B J; Quinn, P W

1994-09-01

Single- and three-phase broad-beam x-ray attenuation data have been obtained using lead, steel, plate glass, gypsum wallboard, lead acrylic, and wood. Tube voltages of 50, 70, 100, 125, and 150 kVp were employed and the resulting curves were compared to transmission data found in the literature. To simplify computation of barrier requirements, all data sets were parametrized by nonlinear least-squares fit to a previously described mathematical model. High attenuation half value layers and the lead equivalence of the alternate materials were also determined.

Laser Doppler Experiments

DTIC Science & Technology

1992-06-19

Spacer material: Zerodur , ULE or equivalent 3. Mirrors to be optically contacted to spacer 4. Mirror surfaces: matched to better than Vd120, after...the mechanical, optical and electronic design of the apparatus to date. The Contraves mount was fitted with new coude mirrors for the YAG laser; the...accuracy  MHz. The choice of mirror reflectances for the interferometer plates and the tolerance to be placed on the field of view have been

Assembly and insertion of a self-fitting hearing aid: design of effective instruction materials.

PubMed

Caposecco, Andrea; Hickson, Louise; Meyer, Carly

2011-12-01

A self-fitting hearing aid has been proposed as a viable option to meet the need for rehabilitation in areas where audiology services are unreliable. A successful outcome with a self-fitting hearing aid pivots in part on the clarity of the instructions accompanying the device. The aims of this article are (a) to review the literature to determine features that should be incorporated into written health-care materials and factors to consider in the design process when developing written instructions for a target audience of older adults and (b) to apply this information to the development of a set of written instructions as the first step in self-fitting of a hearing aid, assembling four parts and inserting the aid into the ear. The method involved a literature review of published peer reviewed research. The literature revealed four steps in the development of written health-care materials: planning, design, assessment of suitability, and pilot testing. Best practice design principles for each step were applied in the development of instructions for how to assemble and insert a hearing aid. Separate booklets were developed for the left and right aids and the content of each consisted of simple line drawings accompanied by captions. The reading level was Grade 3.5 equivalent and the Flesch Reading Ease Score was 91.1 indicating that the materials were "very easy" to read. It is essential to follow best practice design principles when developing written health-care materials to motivate the reader, maximize comprehension, and increase the likelihood of successful application of the content.

SU-C-213-05: Evaluation of a Composite Copper-Plastic Material for a 3D Printed Radiation Therapy Bolus

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

Vitzthum, L; Ehler, E; Sterling, D

2015-06-15

Purpose: To evaluate a novel 3D printed bolus fabricated from a copper-plastic composite as a thin flexible, custom fitting device that can replicate doses achieved with conventional bolus techniques. Methods: Two models of bolus were created on a 3D printer using a composite copper-PLA/PHA. Firstly, boluses were constructed at thicknesses of 0.4, 0.6 and 0.8 mm. Relative dose measurements were performed under the bolus with an Attix Chamber as well as with radiochromic film. Results were compared to superficial Attix Chamber measurements in a water equivalent material to determine the dosimetric water equivalence of the copper-PLA/PHA plastic. Secondly, CT imagesmore » of a RANDO phantom were used to create a custom fitting bolus across the anterolateral scalp. Surface dose with the bolus placed on the RANDO phantom was measured with radiochromic film at tangential angles with 6, 10, 10 flattening filter free (FFF) and 18 MV photon beams. Results: Mean surface doses for 6, 10, 10FFF and 18 MV were measured as a percent of Dmax for the flat bolus devices of each thickness. The 0.4 mm thickness bolus was determined to be near equivalent to 2.5 mm depth in water for all four energies. Surface doses ranged from 59–63% without bolus and 85–90% with the custom 0.4 mm copper-plastic bolus relative to the prescribed dose for an oblique tangential beam arrangement on the RANDO phantom. Conclusion: Sub-millimeter thickness, 3D printed composite copper-PLA/PHA bolus can provide a build-up effect equivalent to conventional bolus. At this thickness, the 3D printed bolus allows a level of flexure that may provide more patient comfort than current 3D printing materials used in bolus fabrication while still retaining the CT based custom patient shape. Funding provided by an intra-department grant of the University of Minnesota Department of Radiation Oncology.« less

Proton exchange membrane fuel cell model for aging predictions: Simulated equivalent active surface area loss and comparisons with durability tests

NASA Astrophysics Data System (ADS)

Robin, C.; Gérard, M.; Quinaud, M.; d'Arbigny, J.; Bultel, Y.

2016-09-01

The prediction of Proton Exchange Membrane Fuel Cell (PEMFC) lifetime is one of the major challenges to optimize both material properties and dynamic control of the fuel cell system. In this study, by a multiscale modeling approach, a mechanistic catalyst dissolution model is coupled to a dynamic PEMFC cell model to predict the performance loss of the PEMFC. Results are compared to two 2000-h experimental aging tests. More precisely, an original approach is introduced to estimate the loss of an equivalent active surface area during an aging test. Indeed, when the computed Electrochemical Catalyst Surface Area profile is fitted on the experimental measures from Cyclic Voltammetry, the computed performance loss of the PEMFC is underestimated. To be able to predict the performance loss measured by polarization curves during the aging test, an equivalent active surface area is obtained by a model inversion. This methodology enables to successfully find back the experimental cell voltage decay during time. The model parameters are fitted from the polarization curves so that they include the global degradation. Moreover, the model captures the aging heterogeneities along the surface of the cell observed experimentally. Finally, a second 2000-h durability test in dynamic operating conditions validates the approach.

Assessment of the Radiation-Equivalent of Chemotherapy Contributions in 1-Phase Radio-chemotherapy Treatment of Muscle-Invasive Bladder Cancer

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

Plataniotis, George A., E-mail: george.plataniotis@nhs.net; Dale, Roger G.

2014-03-15

Purpose: To estimate the radiation equivalent of the chemotherapy contribution to observed complete response rates in published results of 1-phase radio-chemotherapy of muscle-invasive bladder cancer. Methods and Materials: A standard logistic dose–response curve was fitted to data from radiation therapy-alone trials and then used as the platform from which to quantify the chemotherapy contribution in 1-phase radio-chemotherapy trials. Two possible mechanisms of chemotherapy effect were assumed (1) a fixed radiation-independent contribution to local control; or (2) a fixed degree of chemotherapy-induced radiosensitization. A combination of both mechanisms was also considered. Results: The respective best-fit values of the independent chemotherapy-induced completemore » response (CCR) and radiosensitization (s) coefficients were 0.40 (95% confidence interval −0.07 to 0.87) and 1.30 (95% confidence interval 0.86-1.70). Independent chemotherapy effect was slightly favored by the analysis, and the derived CCR value was consistent with reports of pathologic complete response rates seen in neoadjuvant chemotherapy-alone treatments of muscle-invasive bladder cancer. The radiation equivalent of the CCR was 36.3 Gy. Conclusion: Although the data points in the analyzed radio-chemotherapy studies are widely dispersed (largely on account of the diverse range of chemotherapy schedules used), it is nonetheless possible to fit plausible-looking response curves. The methodology used here is based on a standard technique for analyzing dose-response in radiation therapy-alone studies and is capable of application to other mixed-modality treatment combinations involving radiation therapy.« less

Assembly and Insertion of a Self-Fitting Hearing Aid

PubMed Central

Hickson, Louise; Meyer, Carly

2011-01-01

A self-fitting hearing aid has been proposed as a viable option to meet the need for rehabilitation in areas where audiology services are unreliable. A successful outcome with a self-fitting hearing aid pivots in part on the clarity of the instructions accompanying the device. The aims of this article are (a) to review the literature to determine features that should be incorporated into written health-care materials and factors to consider in the design process when developing written instructions for a target audience of older adults and (b) to apply this information to the development of a set of written instructions as the first step in self-fitting of a hearing aid, assembling four parts and inserting the aid into the ear. The method involved a literature review of published peer reviewed research. The literature revealed four steps in the development of written health-care materials: planning, design, assessment of suitability, and pilot testing. Best practice design principles for each step were applied in the development of instructions for how to assemble and insert a hearing aid. Separate booklets were developed for the left and right aids and the content of each consisted of simple line drawings accompanied by captions. The reading level was Grade 3.5 equivalent and the Flesch Reading Ease Score was 91.1 indicating that the materials were “very easy” to read. It is essential to follow best practice design principles when developing written health-care materials to motivate the reader, maximize comprehension, and increase the likelihood of successful application of the content. PMID:22389434

Accurate Measurement of Bone Density with QCT

NASA Technical Reports Server (NTRS)

Cleek, Tammy M.; Beaupre, Gary S.; Matsubara, Miki; Whalen, Robert T.; Dalton, Bonnie P. (Technical Monitor)

2002-01-01

The objective of this study was to determine the accuracy of bone density measurement with a new OCT technology. A phantom was fabricated using two materials, a water-equivalent compound and hydroxyapatite (HA), combined in precise proportions (QRM GrnbH, Germany). The phantom was designed to have the approximate physical size and range in bone density as a human calcaneus, with regions of 0, 50, 100, 200, 400, and 800 mg/cc HA. The phantom was scanned at 80, 120 and 140 KVp with a GE CT/i HiSpeed Advantage scanner. A ring of highly attenuating material (polyvinyl chloride or teflon) was slipped over the phantom to alter the image by introducing non-axi-symmetric beam hardening. Images were corrected with a new OCT technology using an estimate of the effective X-ray beam spectrum to eliminate beam hardening artifacts. The algorithm computes the volume fraction of HA and water-equivalent matrix in each voxel. We found excellent agreement between expected and computed HA volume fractions. Results were insensitive to beam hardening ring material, HA concentration, and scan voltage settings. Data from all 3 voltages with a best fit linear regression are displays.

46 CFR 169.109 - Equivalents.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Equivalents. 169.109 Section 169.109 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS General Provisions § 169.109 Equivalents. Substitutes for a fitting, appliance, apparatus, or equipment, may be...

46 CFR 169.109 - Equivalents.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Equivalents. 169.109 Section 169.109 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS General Provisions § 169.109 Equivalents. Substitutes for a fitting, appliance, apparatus, or equipment, may be...

Research on Al-alloy sheet forming formability during warm/hot sheet hydroforming based on elliptical warm bulging test

NASA Astrophysics Data System (ADS)

Cai, Gaoshen; Wu, Chuanyu; Gao, Zepu; Lang, Lihui; Alexandrov, Sergei

2018-05-01

An elliptical warm/hot sheet bulging test under different temperatures and pressure rates was carried out to predict Al-alloy sheet forming limit during warm/hot sheet hydroforming. Using relevant formulas of ultimate strain to calculate and dispose experimental data, forming limit curves (FLCS) in tension-tension state of strain (TTSS) area are obtained. Combining with the basic experimental data obtained by uniaxial tensile test under the equivalent condition with bulging test, complete forming limit diagrams (FLDS) of Al-alloy are established. Using a quadratic polynomial curve fitting method, material constants of fitting function are calculated and a prediction model equation for sheet metal forming limit is established, by which the corresponding forming limit curves in TTSS area can be obtained. The bulging test and fitting results indicated that the sheet metal FLCS obtained were very accurate. Also, the model equation can be used to instruct warm/hot sheet bulging test.

DOD Ammunition and Explosives Safety Standards

DTIC Science & Technology

2008-02-29

8. The equivalent explosive weight of the hybrid rocket system N2O4 liquid oxidizer combined with PBAN solid fuel was evaluated as 15 percent for an...separate isolated system and fitting types to preclude intermixing, and the energetic liquids are of required purity. Otherwise, equivalent...Water outlets in a toxic chemical agent operational facility shall be fitted with backflow devices. C11.8.2.7. Dedicated liquid waste systems

Multi-modality gellan gum-based tissue-mimicking phantom with targeted mechanical, electrical, and thermal properties.

PubMed

Chen, Roland K; Shih, A J

2013-08-21

This study develops a new class of gellan gum-based tissue-mimicking phantom material and a model to predict and control the elastic modulus, thermal conductivity, and electrical conductivity by adjusting the mass fractions of gellan gum, propylene glycol, and sodium chloride, respectively. One of the advantages of gellan gum is its gelling efficiency allowing highly regulable mechanical properties (elastic modulus, toughness, etc). An experiment was performed on 16 gellan gum-based tissue-mimicking phantoms and a regression model was fit to quantitatively predict three material properties (elastic modulus, thermal conductivity, and electrical conductivity) based on the phantom material's composition. Based on these material properties and the regression model developed, tissue-mimicking phantoms of porcine spinal cord and liver were formulated. These gellan gum tissue-mimicking phantoms have the mechanical, thermal, and electrical properties approximately equivalent to those of the spinal cord and the liver.

Material Properties from Air Puff Corneal Deformation by Numerical Simulations on Model Corneas.

PubMed

Bekesi, Nandor; Dorronsoro, Carlos; de la Hoz, Andrés; Marcos, Susana

2016-01-01

To validate a new method for reconstructing corneal biomechanical properties from air puff corneal deformation images using hydrogel polymer model corneas and porcine corneas. Air puff deformation imaging was performed on model eyes with artificial corneas made out of three different hydrogel materials with three different thicknesses and on porcine eyes, at constant intraocular pressure of 15 mmHg. The cornea air puff deformation was modeled using finite elements, and hyperelastic material parameters were determined through inverse modeling, minimizing the difference between the simulated and the measured central deformation amplitude and central-peripheral deformation ratio parameters. Uniaxial tensile tests were performed on the model cornea materials as well as on corneal strips, and the results were compared to stress-strain simulations assuming the reconstructed material parameters. The measured and simulated spatial and temporal profiles of the air puff deformation tests were in good agreement (< 7% average discrepancy). The simulated stress-strain curves of the studied hydrogel corneal materials fitted well the experimental stress-strain curves from uniaxial extensiometry, particularly in the 0-0.4 range. Equivalent Young´s moduli of the reconstructed material properties from air-puff were 0.31, 0.58 and 0.48 MPa for the three polymer materials respectively which differed < 1% from those obtained from extensiometry. The simulations of the same material but different thickness resulted in similar reconstructed material properties. The air-puff reconstructed average equivalent Young´s modulus of the porcine corneas was 1.3 MPa, within 18% of that obtained from extensiometry. Air puff corneal deformation imaging with inverse finite element modeling can retrieve material properties of model hydrogel polymer corneas and real corneas, which are in good correspondence with those obtained from uniaxial extensiometry, suggesting that this is a promising technique to retrieve quantitative corneal biomechanical properties.

Synthesized tissue-equivalent dielectric phantoms using salt and polyvinylpyrrolidone solutions.

PubMed

Ianniello, Carlotta; de Zwart, Jacco A; Duan, Qi; Deniz, Cem M; Alon, Leeor; Lee, Jae-Seung; Lattanzi, Riccardo; Brown, Ryan

2018-07-01

To explore the use of polyvinylpyrrolidone (PVP) for simulated materials with tissue-equivalent dielectric properties. PVP and salt were used to control, respectively, relative permittivity and electrical conductivity in a collection of 63 samples with a range of solute concentrations. Their dielectric properties were measured with a commercial probe and fitted to a 3D polynomial in order to establish an empirical recipe. The material's thermal properties and MR spectra were measured. The empirical polynomial recipe (available at https://www.amri.ninds.nih.gov/cgi-bin/phantomrecipe) provides the PVP and salt concentrations required for dielectric materials with permittivity and electrical conductivity values between approximately 45 and 78, and 0.1 to 2 siemens per meter, respectively, from 50 MHz to 4.5 GHz. The second- (solute concentrations) and seventh- (frequency) order polynomial recipe provided less than 2.5% relative error between the measured and target properties. PVP side peaks in the spectra were minor and unaffected by temperature changes. PVP-based phantoms are easy to prepare and nontoxic, and their semitransparency makes air bubbles easy to identify. The polymer can be used to create simulated material with a range of dielectric properties, negligible spectral side peaks, and long T 2 relaxation time, which are favorable in many MR applications. Magn Reson Med 80:413-419, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

The organic surface of 5145 Pholus: Constraints set by scattering theory

NASA Technical Reports Server (NTRS)

Wilson, Peter D.; Sagan, Carl; Thompson, W. Reid

1994-01-01

No known body in the Solar System has a spectrum redder than that of object 5145 Pholus. We use Hapke scattering theory and optical constants measured in this laboratory to examine the ability of mixtures of a number of organic solids and ices to reproduce the observed spectrum and phase variation. The primary materials considered are poly-HCN, kerogen, Murchison organic extract, Titan tholin, ice tholin, and water ice. In a computer grid search of over 10 million models, we find an intraparticle mixture of 15% Titan tholin, 10% poly-HCN, and 75% water ice with 10-micrometers particles to provide an excellent fit. Replacing water ice with ammonia ice improves the fits significantly while using a pure hydrocarbon tholin, Tholin alpha, instead of Titan tholin makes only modest improvements. All acceptable fits require Titan tholin or some comparable material to provide the steep slope in the visible, and poly-HCN or some comparable material to provide strong absorption in the near-infrared. A pure Titan tholin surface with 16-micrometers particles, as well as all acceptable Pholus models, fit the present spectrophotometric data for the transplutonian object 1992 QB(sub 1). The feasibility of gas-phase chemistry to generate material like Titan tholin on such small objects is examined. An irradiated transient atmosphere arising from sublimating ices may generate at most a few centimeters of tholin over the lifetime of the Solar System, but this is insignificant compared to the expected lag deposit of primordial contaminants left behind by the sublimating ice. Irradiation of subsurface N2/CH4 or NH3/CH4 ice by cosmic rays may generate approximately 20 cm of tholin in the upper 10 m of regolith in the same time scale but the identity of this tholin to its gas-phase equivalent has not been demonstrated.

Polyvinylidene fluoride membranes probed by electrochemical impedance spectroscopy

NASA Astrophysics Data System (ADS)

Luo, Qi-Zhao; Huang, Qing; Chen, Zhe; Yao, Lei; Fu, Ping; Lin, Zhi-Dong

2018-06-01

Electrochemical impedance spectroscopy (EIS) has been applied to characterize the structure of polyvinylidene fluoride (PVDF) membranes. The characteristic frequency, which directly obtained from the original EIS data, was used to clarify the difference of the membranes’ structures. The experimental data indicated the equivalence between the characteristic frequency and the membrane resistance fitted from the equivalent circuit. The results evidenced that the characteristic frequency obtained directly from original EIS data without any fitting calculation can be used for in situ characterizing a membrane instead of the membrane resistance.

Generalized Fractional Derivative Anisotropic Viscoelastic Characterization.

PubMed

Hilton, Harry H

2012-01-18

Isotropic linear and nonlinear fractional derivative constitutive relations are formulated and examined in terms of many parameter generalized Kelvin models and are analytically extended to cover general anisotropic homogeneous or non-homogeneous as well as functionally graded viscoelastic material behavior. Equivalent integral constitutive relations, which are computationally more powerful, are derived from fractional differential ones and the associated anisotropic temperature-moisture-degree-of-cure shift functions and reduced times are established. Approximate Fourier transform inversions for fractional derivative relations are formulated and their accuracy is evaluated. The efficacy of integer and fractional derivative constitutive relations is compared and the preferential use of either characterization in analyzing isotropic and anisotropic real materials must be examined on a case-by-case basis. Approximate protocols for curve fitting analytical fractional derivative results to experimental data are formulated and evaluated.

[The effect of composition and structure of radiological equivalent materials on radiological equivalent].

PubMed

Wang, Y; Lin, D; Fu, T

1997-03-01

Morphology of inorganic material powders before and after being treated by ultrafine crush was observed by transformite electron microscope. The length and diameter of granules were measured. Polymers inorganic material powders before and after being treated by ultrafine crush were used for preparing radiological equivalent materials. Blending compatibility of inorganic meterials with polymer materials was observed by scanning electron microscope. CT values of tissue equivalent materials were measured by X-ray CT. Distribution of inorganic materials was examined. The compactness of materials was determined by the water absorbed method. The elastic module of materials was measured by laser speckle interferementry method. The results showed that the inorganic material powders treated by the ultrafine crush blent well with polymer and the distribution of these powders in the polymer was homogeneous. The equivalent errors of linear attenuation coefficients and CT values of equivalent materials were small. Their elastic modules increased one order of magnitude from 6.028 x 10(2) kg/cm2 to 9.753 x 10(3) kg/cm2. In addition, the rod inorganic material powders having rod granule blent easily with polymer. The present study provides a theoretical guidance and experimental basis for the design and synthesis of radiological equivalent materials.

Reduced cardiovascular fitness associated with exposure to clozapine in individuals with chronic schizophrenia.

PubMed

Kim, David D; Lang, Donna J; Procyshyn, Ric M; Woodward, Melissa L; Kaufman, Kai; White, Randall F; Honer, William G; Warburton, Darren E R

2018-04-01

Studies show that individuals with schizophrenia have impaired cardiovascular fitness (i.e., low peak aerobic power (VO 2 peak)). It is speculated that antipsychotics with adverse cardiovascular and metabolic profiles, in particular clozapine, have a significant impact on VO 2 peak. In this cross-sectional study, we examined whether exposure to clozapine was associated with further reduced VO 2 peak compared with non-clozapine antipsychotics. Thirty participants with chronic schizophrenia or schizoaffective disorder were divided into clozapine and non-clozapine groups. Mean daily doses of antipsychotics were standardized to chlorpromazine equivalents and haloperidol equivalents for antagonism of alpha 1 - and alpha 2 -adrenergic receptors. Participants completed an incremental-to-maximal symptom-limited exercise test on a cycle ergometer for the assessment of VO 2 peak. The clozapine group demonstrated significantly lower VO 2 peak than the non-clozapine group. Haloperidol equivalents for alpha-adrenergic receptor antagonism, but not chlorpromazine equivalents, demonstrated significant inverse associations with VO 2 peak. The clozapine group had a significantly higher amount of antagonistic activity at alpha-adrenergic receptors than the non-clozapine group. In conclusion, exposure to clozapine was associated with further reduced cardiovascular fitness, which may be explained by the drug's greater antagonistic activity at alpha-adrenergic receptors. Cardiovascular fitness needs to be promoted in individuals treated with antipsychotics, particularly clozapine, to prevent the risk of cardiovascular disease and mortality. Copyright © 2018 Elsevier B.V. All rights reserved.

Determining Intensity Levels of Selected Wii Fit Activities in College Aged Individuals

ERIC Educational Resources Information Center

Grieser, Joshua D.; Gao, Yong; Ransdell, Lynda; Simonson, Shawn

2012-01-01

The purpose of this study was to determine the intensity of Nintendo Wii Fit games using indirect calorimetry. Twenty-five college students completed Wii Fit activity sessions at two difficulty levels within aerobics, strength, and yoga categories. Resting metabolic rate and exercise oxygen uptake were measured, and metabolic equivalents were…

Material Properties from Air Puff Corneal Deformation by Numerical Simulations on Model Corneas

PubMed Central

Dorronsoro, Carlos; de la Hoz, Andrés; Marcos, Susana

2016-01-01

Objective To validate a new method for reconstructing corneal biomechanical properties from air puff corneal deformation images using hydrogel polymer model corneas and porcine corneas. Methods Air puff deformation imaging was performed on model eyes with artificial corneas made out of three different hydrogel materials with three different thicknesses and on porcine eyes, at constant intraocular pressure of 15 mmHg. The cornea air puff deformation was modeled using finite elements, and hyperelastic material parameters were determined through inverse modeling, minimizing the difference between the simulated and the measured central deformation amplitude and central-peripheral deformation ratio parameters. Uniaxial tensile tests were performed on the model cornea materials as well as on corneal strips, and the results were compared to stress-strain simulations assuming the reconstructed material parameters. Results The measured and simulated spatial and temporal profiles of the air puff deformation tests were in good agreement (< 7% average discrepancy). The simulated stress-strain curves of the studied hydrogel corneal materials fitted well the experimental stress-strain curves from uniaxial extensiometry, particularly in the 0–0.4 range. Equivalent Young´s moduli of the reconstructed material properties from air-puff were 0.31, 0.58 and 0.48 MPa for the three polymer materials respectively which differed < 1% from those obtained from extensiometry. The simulations of the same material but different thickness resulted in similar reconstructed material properties. The air-puff reconstructed average equivalent Young´s modulus of the porcine corneas was 1.3 MPa, within 18% of that obtained from extensiometry. Conclusions Air puff corneal deformation imaging with inverse finite element modeling can retrieve material properties of model hydrogel polymer corneas and real corneas, which are in good correspondence with those obtained from uniaxial extensiometry, suggesting that this is a promising technique to retrieve quantitative corneal biomechanical properties. PMID:27792759

NTCP Modeling of Subacute/Late Laryngeal Edema Scored by Fiberoptic Examination

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

Rancati, Tiziana; Fiorino, Claudio, E-mail: fiorino.claudio@hsr.i; Sanguineti, Giuseppe

2009-11-01

Purpose: Finding best-fit parameters of normal tissue complication probability (NTCP) models for laryngeal edema after radiotherapy for head and neck cancer. Methods and Materials: Forty-eight patients were considered for this study who met the following criteria: (1) grossly uninvolved larynx, (2) no prior major surgery except for neck dissection and tonsillectomy, (3) at least one fiberoptic examination of the larynx within 2 years from radiotherapy, (4) minimum follow-up of 15 months. Larynx dose-volume histograms (DVHs) were corrected into a linear quadratic equivalent one at 2 Gy/fr with alpha/beta = 3 Gy. Subacute/late edema was prospectively scored at each follow-up examinationmore » according to the Radiation Therapy Oncology Group scale. G2-G3 edema within 15 months from RT was considered as our endpoint. Two NTCP models were considered: (1) the Lyman model with DVH reduced to the equivalent uniform dose (EUD; LEUD) and (2) the Logit model with DVH reduced to the EUD (LOGEUD). The parameters for the models were fit to patient data using a maximum likelihood analysis. Results: All patients had a minimum of 15 months follow-up (only 8/48 received concurrent chemotherapy): 25/48 (52.1%) experienced G2-G3 edema. Both NTCP models fit well the clinical data: with LOGEUD the relationship between EUD and NTCP can be described with TD50 = 46.7 +- 2.1 Gy, n = 1.41 +- 0.8 and a steepness parameter k = 7.2 +- 2.5 Gy. Best fit parameters for LEUD are n = 1.17 +- 0.6, m = 0.23 +- 0.07 and TD50 = 47.3 +- 2.1 Gy. Conclusions: A clear volume effect was found for edema, consistent with a parallel architecture of the larynx for this endpoint. On the basis of our findings, an EUD <30-35 Gy should drastically reduce the risk of G2-G3 edema.« less

Using Generalized Equivalent Uniform Dose Atlases to Combine and Analyze Prospective Dosimetric and Radiation Pneumonitis Data From 2 Non-Small Cell Lung Cancer Dose Escalation Protocols

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

Liu Fan; Yorke, Ellen D.; Belderbos, Jose S.A.

2013-01-01

Purpose: To demonstrate the use of generalized equivalent uniform dose (gEUD) atlas for data pooling in radiation pneumonitis (RP) modeling, to determine the dependence of RP on gEUD, to study the consistency between data sets, and to verify the increased statistical power of the combination. Methods and Materials: Patients enrolled in prospective phase I/II dose escalation studies of radiation therapy of non-small cell lung cancer at Memorial Sloan-Kettering Cancer Center (MSKCC) (78 pts) and the Netherlands Cancer Institute (NKI) (86 pts) were included; 10 (13%) and 14 (17%) experienced RP requiring steroids (RPS) within 6 months after treatment. gEUD wasmore » calculated from dose-volume histograms. Atlases for each data set were created using 1-Gy steps from exact gEUDs and RPS data. The Lyman-Kutcher-Burman model was fit to the atlas and exact gEUD data. Heterogeneity and inconsistency statistics for the fitted parameters were computed. gEUD maps of the probability of RPS rate {>=}20% were plotted. Results: The 2 data sets were homogeneous and consistent. The best fit values of the volume effect parameter a were small, with upper 95% confidence limit around 1.0 in the joint data. The likelihood profiles around the best fit a values were flat in all cases, making determination of the best fit a weak. All confidence intervals (CIs) were narrower in the joint than in the individual data sets. The minimum P value for correlations of gEUD with RPS in the joint data was .002, compared with P=.01 and .05 for MSKCC and NKI data sets, respectively. gEUD maps showed that at small a, RPS risk increases with gEUD. Conclusions: The atlas can be used to combine gEUD and RPS information from different institutions and model gEUD dependence of RPS. RPS has a large volume effect with the mean dose model barely included in the 95% CI. Data pooling increased statistical power.« less

Effect of Cerium Doped on the Poly(3-(Trimethoxysilyl)propyl methacrylate) Characteristic as Corrosion Protection Material of Carbon Steel

NASA Astrophysics Data System (ADS)

Rochmah, D. N.; Syakir, N.; Susilawati, T.; Suryaningsih, S.; Fitrilawati

2017-05-01

The hybrid polymer precursor was synthesized from monomer of 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) using sol-gel method and doped with inhibitor of Cerium Nitrate Hexahydrate with a concentration of 0.2%. The synthesized material was coated on a carbon steel surface by solution casting technique and followed by a photopolymerisation process. Corrosion tests were performed by using Electrochemical Impedance Spectroscopy (EIS) in 3.5% NaCl at the critical temperature of 75°C. Result of EIS data and their fitting analysis using an equivalent circuit model shows that a coating of poly(TMSPMA)-Cerium on the surface of carbon steel form a layer of protection and caused increasing of impedance value significantly. The impedance is higher compared to the carbon steel that coated with poly(TMSPMA) only.

Modelling the Impact of Fractionation on Late Urinary Toxicity After Postprostatectomy Radiation Therapy

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

Fiorino, Claudio, E-mail: fiorino.claudio@hsr.it; Cozzarini, Cesare; Rancati, Tiziana

2014-12-01

Purpose: To fit urinary toxicity data of patients treated with postprostatectomy radiation therapy with the linear quadratic (LQ) model with/without introducing a time factor. Methods and Materials: Between 1993 and 2010, 1176 patients were treated with conventional fractionation (1.8 Gy per fraction, median 70.2 Gy, n=929) or hypofractionation (2.35-2.90 Gy per fraction, n=247). Data referred to 2004-2010 (when all schemes were in use, n=563; conventional fractionation: 316; hypofractionation: 247) were fitted as a logit function of biological equivalent dose (BED), according to the LQ model with/without including a time factor γ (fixing α/β = 5 Gy). The 3-year risks of severe urethral stenosis, incontinence, and hematuriamore » were considered as endpoints. Best-fit parameters were derived, and the resulting BEDs were taken in multivariable backward logistic models, including relevant clinical variables, considering the whole population. Results: The 3-year incidences of severe stenosis, incontinence, and hematuria were, respectively, 6.6%, 4.8%, and 3.3% in the group treated in 2004-2010. The best-fitted α/β values were 0.81 Gy and 0.74 Gy for incontinence and hematuria, respectively, with the classic LQ formula. When fixing α/β = 5 Gy, best-fit values for γ were, respectively, 0.66 Gy/d and 0.85 Gy/d. Sensitivity analyses showed reasonable values for γ (0.6-1.0 Gy/d), with comparable goodness of fit for α/β values between 3.5 and 6.5 Gy. Likelihood ratio tests showed that the fits with/without including γ were equivalent. The resulting multivariable backward logistic models in the whole population included BED, pT4, and use of antihypertensives (area under the curve [AUC] = 0.72) for incontinence and BED, pT4, and year of surgery (AUC = 0.80) for hematuria. Stenosis data could not be fitted: a 4-variable model including only clinical factors (acute urinary toxicity, pT4, year of surgery, and use of antihypertensives) was suggested (AUC = 0.73). Conclusions: The unexpected impact of moderate hypofractionation on severe incontinence and hematuria after postprostatectomy radiation therapy may be explained by a bladder α/β value <1 Gy or, radiobiologically more plausible, by introducing a time factor likely to represent a previously hypothesized consequential component of late effect.« less

40 CFR 53.1 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... followed by a gravimetric mass determination, but which is not a Class I equivalent method because of... MONITORING REFERENCE AND EQUIVALENT METHODS General Provisions § 53.1 Definitions. Terms used but not defined... slope of a linear plot fitted to corresponding candidate and reference method mean measurement data...

Effects of immobilization mask material on surface dose

PubMed Central

Hadley, Scott W.; Kelly, Robin; Lam, Kwok

2005-01-01

This work investigates the increase in surface dose caused by thermoplastic masks used for patient positioning and immobilization. A thermoplastic mask is custom fit by stretching a heated mask over the patient at the time of treatment simulation. This mask is then used at treatment to increase the reproducibility of the patient position. The skin sparing effect of mega‐voltage X‐ray beams can be reduced when the patient's skin surface is under the mask material. The sheet of thermoplastic mask has holes to reduce this effect and is available from one manufacturer with two different sizes of holes, one larger than the other. This work investigates the increase in surface dose caused by the mask material and quantifies the difference between the two samples of masks available. The change in the dose buildup was measured using an Attix parallel plate chamber by measuring tissue maximum ratios (TMRs) using solid water. Measurements were made with and without the mask material on the surface of the solid water for 6‐MV and 15‐MV X‐ray beams. The effective thickness of equivalent water was estimated from the TMR curves, and the increase in surface dose was estimated. The buildup effect was measured to be equivalent to 2.2 mm to 0.6 mm for masks that have been stretched by different amounts. The surface dose was estimated to change from 16% and 12% for 6 MV and 15 MV, respectively, to 27% to 61% for 6 MV and 18% to 40% for 15 MV with the mask samples. PACS number: 87.53.Dq PMID:15770192

Particle size distributions by transmission electron microscopy: an interlaboratory comparison case study

PubMed Central

Rice, Stephen B; Chan, Christopher; Brown, Scott C; Eschbach, Peter; Han, Li; Ensor, David S; Stefaniak, Aleksandr B; Bonevich, John; Vladár, András E; Hight Walker, Angela R; Zheng, Jiwen; Starnes, Catherine; Stromberg, Arnold; Ye, Jia; Grulke, Eric A

2015-01-01

This paper reports an interlaboratory comparison that evaluated a protocol for measuring and analysing the particle size distribution of discrete, metallic, spheroidal nanoparticles using transmission electron microscopy (TEM). The study was focused on automated image capture and automated particle analysis. NIST RM8012 gold nanoparticles (30 nm nominal diameter) were measured for area-equivalent diameter distributions by eight laboratories. Statistical analysis was used to (1) assess the data quality without using size distribution reference models, (2) determine reference model parameters for different size distribution reference models and non-linear regression fitting methods and (3) assess the measurement uncertainty of a size distribution parameter by using its coefficient of variation. The interlaboratory area-equivalent diameter mean, 27.6 nm ± 2.4 nm (computed based on a normal distribution), was quite similar to the area-equivalent diameter, 27.6 nm, assigned to NIST RM8012. The lognormal reference model was the preferred choice for these particle size distributions as, for all laboratories, its parameters had lower relative standard errors (RSEs) than the other size distribution reference models tested (normal, Weibull and Rosin–Rammler–Bennett). The RSEs for the fitted standard deviations were two orders of magnitude higher than those for the fitted means, suggesting that most of the parameter estimate errors were associated with estimating the breadth of the distributions. The coefficients of variation for the interlaboratory statistics also confirmed the lognormal reference model as the preferred choice. From quasi-linear plots, the typical range for good fits between the model and cumulative number-based distributions was 1.9 fitted standard deviations less than the mean to 2.3 fitted standard deviations above the mean. Automated image capture, automated particle analysis and statistical evaluation of the data and fitting coefficients provide a framework for assessing nanoparticle size distributions using TEM for image acquisition. PMID:26361398

Electrochemical Analysis of Conducting Polymer Thin Films

PubMed Central

Vyas, Ritesh N.; Wang, Bin

2010-01-01

Polyelectrolyte multilayers built via the layer-by-layer (LbL) method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material by means of electrostatic interaction. The thickness of the adsorbed layers can be tuned precisely in the nanometer range. Stable, semiconducting thin films are interesting research subjects. We use a conducting polymer, poly(p-phenylene vinylene) (PPV), in the preparation of a stable thin film via the LbL method. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to characterize the ionic conductivity of the PPV multilayer films. The ionic conductivity of the films has been found to be dependent on the polymerization temperature. The film conductivity can be fitted to a modified Randle’s circuit. The circuit equivalent calculations are performed to provide the diffusion coefficient values. PMID:20480052

Quantification of biological tissue and construction of patient equivalent phantom (skull and chest) for infants (1-5 years old)

NASA Astrophysics Data System (ADS)

Alves, A. F.; Pina, D. R.; Bacchim Neto, F. A.; Ribeiro, S. M.; Miranda, J. R. A.

2014-03-01

Our main purpose in this study was to quantify biological tissue in computed tomography (CT) examinations with the aim of developing a skull and a chest patient equivalent phantom (PEP), both specific to infants, aged between 1 and 5 years old. This type of phantom is widely used in the development of optimization procedures for radiographic techniques, especially in computed radiography (CR) systems. In order to classify and quantify the biological tissue, we used a computational algorithm developed in Matlab ®. The algorithm performed a histogram of each CT slice followed by a Gaussian fitting of each tissue type. The algorithm determined the mean thickness for the biological tissues (bone, soft, fat, and lung) and also converted them into the corresponding thicknesses of the simulator material (aluminum, PMMA, and air). We retrospectively analyzed 148 CT examinations of infant patients, 56 for skull exams and 92 were for chest. The results provided sufficient data to construct a phantom to simulate the infant chest and skull in the posterior-anterior or anterior-posterior (PA/AP) view. Both patient equivalent phantoms developed in this study can be used to assess physical variables such as noise power spectrum (NPS) and signal to noise ratio (SNR) or perform dosimetric control specific to pediatric protocols.

New Objective Refraction Metric Based on Sphere Fitting to the Wavefront

PubMed Central

Martínez-Finkelshtein, Andreí

2017-01-01

Purpose To develop an objective refraction formula based on the ocular wavefront error (WFE) expressed in terms of Zernike coefficients and pupil radius, which would be an accurate predictor of subjective spherical equivalent (SE) for different pupil sizes. Methods A sphere is fitted to the ocular wavefront at the center and at a variable distance, t. The optimal fitting distance, topt, is obtained empirically from a dataset of 308 eyes as a function of objective refraction pupil radius, r0, and used to define the formula of a new wavefront refraction metric (MTR). The metric is tested in another, independent dataset of 200 eyes. Results For pupil radii r0 ≤ 2 mm, the new metric predicts the equivalent sphere with similar accuracy (<0.1D), however, for r0 > 2 mm, the mean error of traditional metrics can increase beyond 0.25D, and the MTR remains accurate. The proposed metric allows clinicians to obtain an accurate clinical spherical equivalent value without rescaling/refitting of the wavefront coefficients. It has the potential to be developed into a metric which will be able to predict full spherocylindrical refraction for the desired illumination conditions and corresponding pupil size. PMID:29104804

New Objective Refraction Metric Based on Sphere Fitting to the Wavefront.

PubMed

Jaskulski, Mateusz; Martínez-Finkelshtein, Andreí; López-Gil, Norberto

2017-01-01

To develop an objective refraction formula based on the ocular wavefront error (WFE) expressed in terms of Zernike coefficients and pupil radius, which would be an accurate predictor of subjective spherical equivalent (SE) for different pupil sizes. A sphere is fitted to the ocular wavefront at the center and at a variable distance, t . The optimal fitting distance, t opt , is obtained empirically from a dataset of 308 eyes as a function of objective refraction pupil radius, r 0 , and used to define the formula of a new wavefront refraction metric (MTR). The metric is tested in another, independent dataset of 200 eyes. For pupil radii r 0 ≤ 2 mm, the new metric predicts the equivalent sphere with similar accuracy (<0.1D), however, for r 0 > 2 mm, the mean error of traditional metrics can increase beyond 0.25D, and the MTR remains accurate. The proposed metric allows clinicians to obtain an accurate clinical spherical equivalent value without rescaling/refitting of the wavefront coefficients. It has the potential to be developed into a metric which will be able to predict full spherocylindrical refraction for the desired illumination conditions and corresponding pupil size.

Attenuation analysis of real GPR wavelets: The equivalent amplitude spectrum (EAS)

NASA Astrophysics Data System (ADS)

Economou, Nikos; Kritikakis, George

2016-03-01

Absorption of a Ground Penetrating Radar (GPR) pulse is a frequency dependent attenuation mechanism which causes a spectral shift on the dominant frequency of GPR data. Both energy variation of GPR amplitude spectrum and spectral shift were used for the estimation of Quality Factor (Q*) and subsequently the characterization of the subsurface material properties. The variation of the amplitude spectrum energy has been studied by Spectral Ratio (SR) method and the frequency shift by the estimation of the Frequency Centroid Shift (FCS) or the Frequency Peak Shift (FPS) methods. The FPS method is more automatic, less robust. This work aims to increase the robustness of the FPS method by fitting a part of the amplitude spectrum of GPR data with Ricker, Gaussian, Sigmoid-Gaussian or Ricker-Gaussian functions. These functions fit different parts of the spectrum of a GPR reference wavelet and the Equivalent Amplitude Spectrum (EAS) is selected, reproducing Q* values used in forward Q* modeling analysis. Then, only the peak frequencies and the time differences between the reference wavelet and the subsequent reflected wavelets are used to estimate Q*. As long as the EAS is estimated, it is used for Q* evaluation in all the GPR section, under the assumption that the selected reference wavelet is representative. De-phasing and constant phase shift, for obtaining symmetrical wavelets, proved useful in the sufficiency of the horizons picking. Synthetic, experimental and real GPR data were examined in order to demonstrate the effectiveness of the proposed methodology.

46 CFR 72.05-25 - Doors, other than watertight.

Code of Federal Regulations, 2011 CFR

2011-10-01

... glass shall be fitted in steel or equivalent metal frames and shall be retained by steel or equivalent metal glazing beads or angles. (5) Where wire-inserted glass is required, and the single wire type is.... The cut for the hose port should be approximately 6 inches square. A hinged or pivoted steel or...

46 CFR 72.05-25 - Doors, other than watertight.

Code of Federal Regulations, 2010 CFR

2010-10-01

... glass shall be fitted in steel or equivalent metal frames and shall be retained by steel or equivalent metal glazing beads or angles. (5) Where wire-inserted glass is required, and the single wire type is.... The cut for the hose port should be approximately 6 inches square. A hinged or pivoted steel or...

46 CFR 72.05-30 - Windows and airports.

Code of Federal Regulations, 2011 CFR

2011-10-01

... strength purposes in certain locations. All glass shall be fitted in steel or equivalent metal frames and shall be retained by steel or equivalent metal glazing beads or angles. (b) Where wire-inserted glass is required, and the single wire type is employed, the strands shall run horizontally and shall be not more...

46 CFR 72.05-30 - Windows and airports.

Code of Federal Regulations, 2010 CFR

2010-10-01

... strength purposes in certain locations. All glass shall be fitted in steel or equivalent metal frames and shall be retained by steel or equivalent metal glazing beads or angles. (b) Where wire-inserted glass is required, and the single wire type is employed, the strands shall run horizontally and shall be not more...

Determination of shielding requirements for mammography.

PubMed

Okunade, Akintunde Akangbe; Ademoroti, Olalekan Albert

2004-05-01

Shielding requirements for mammography when considerations are to be given to attenuation by compression paddle, breast tissue, grid and image receptor (intervening materials) has been investigated. By matching of the attenuation and hardening properties, comparisons are made between shielding afforded by breast tissue materials (water, Lucite and 50%-50% adipose-glandular tissue) and some materials considered for shielding diagnostic x-ray beams, namely lead, steel and gypsum wallboard. Results show that significant differences exist between the thickness required to produce equal attenuation and that required to produce equal hardening of a given incident beam. While attenuation equivalent thickness produces equal exposure, it does not produce equal hardening. For shielding purposes, equivalence in exposure reduction without equivalence in penetrating power of an emerging beam does not amount to equivalence in shielding affordable by two different materials. Presented are models and results of sample calculations of additional shielding requirements apart from that provided by intervening materials. The shielding requirements for the integrated beam emerging from intervening materials are different from those for the integrated beam emerging from materials (lead/steel/gypsum wallboard) with attenuation equivalent thicknesses of these intervening materials.

Characterization of viscoelastic response and damping of composite materials used in flywheel rotors

NASA Astrophysics Data System (ADS)

Chen, Jianmin

The long-term goal for spacecraft flywheel systems with higher energy density at the system level requires new and innovative composite material concepts. Multi-Direction Composite (MDC) offers significant advantages over traditional filament-wound and multi-ring press-fit filament-wound wheels in providing higher energy density (i.e., less mass), better crack resistance, and enhanced safety. However there is a lack of systematic characterization for dynamic properties of MDC composite materials. In order to improve the flywheel materials reliability, durability and life time, it is very important to evaluate the time dependent aging effects and damping properties of MDC material, which are significant dynamic parameter for vibration and sound control, fatigue endurance, and impact resistance. The physical aging effects are quantified based on a set of creep curves measured at different aging time or different aging temperature. One parameter (tau) curve fit was proposed to represent the relationship of aging time and aging temperature between different master curves. The long term mechanical behavior was predicted by obtained master curves. The time and temperature shift factors of matrix were obtained from creep curves and the aging time shift rate were calculated. The aging effects on composite are obtained from experiments and compared with prediction. The mechanical quasi-behavior of MDC composite was analyzed. The correspondence principle was used to relate quasi-static elastic properties of composite materials to time-dependent properties of its constituent materials (i.e., fiber and matrix). The Prony series combined with the multi-data fitting method was applied to inverse Laplace transform and to calculate the time dependent stiffness matrix effectively. Accelerated time-dependent deformation of two flywheel rim designs were studied for a period equivalent to 31 years and are compared with hoop reinforcement only composite. Damping of pure resin and T700/epoxy composite lamina and laminate in longitudinal and transverse directions were investigated experimentally and analytically. The effect of aging on damping was also studied by placing samples at 60°C in an oven for extended periods. Damping master curves versus frequency were constructed from individual curves at different temperatures based on the Arrhenius equation. The damping response of the composite lamina was used to predict the response of laminate composites. Analytical results give close numerical values to experimental results from damping of cantilever beam laminated composite samples.

Normal Tissue Complication Probability Modeling of Radiation-Induced Hypothyroidism After Head-and-Neck Radiation Therapy

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

Bakhshandeh, Mohsen; Hashemi, Bijan, E-mail: bhashemi@modares.ac.ir; Mahdavi, Seied Rabi Mehdi

Purpose: To determine the dose-response relationship of the thyroid for radiation-induced hypothyroidism in head-and-neck radiation therapy, according to 6 normal tissue complication probability models, and to find the best-fit parameters of the models. Methods and Materials: Sixty-five patients treated with primary or postoperative radiation therapy for various cancers in the head-and-neck region were prospectively evaluated. Patient serum samples (tri-iodothyronine, thyroxine, thyroid-stimulating hormone [TSH], free tri-iodothyronine, and free thyroxine) were measured before and at regular time intervals until 1 year after the completion of radiation therapy. Dose-volume histograms (DVHs) of the patients' thyroid gland were derived from their computed tomography (CT)-basedmore » treatment planning data. Hypothyroidism was defined as increased TSH (subclinical hypothyroidism) or increased TSH in combination with decreased free thyroxine and thyroxine (clinical hypothyroidism). Thyroid DVHs were converted to 2 Gy/fraction equivalent doses using the linear-quadratic formula with {alpha}/{beta} = 3 Gy. The evaluated models included the following: Lyman with the DVH reduced to the equivalent uniform dose (EUD), known as LEUD; Logit-EUD; mean dose; relative seriality; individual critical volume; and population critical volume models. The parameters of the models were obtained by fitting the patients' data using a maximum likelihood analysis method. The goodness of fit of the models was determined by the 2-sample Kolmogorov-Smirnov test. Ranking of the models was made according to Akaike's information criterion. Results: Twenty-nine patients (44.6%) experienced hypothyroidism. None of the models was rejected according to the evaluation of the goodness of fit. The mean dose model was ranked as the best model on the basis of its Akaike's information criterion value. The D{sub 50} estimated from the models was approximately 44 Gy. Conclusions: The implemented normal tissue complication probability models showed a parallel architecture for the thyroid. The mean dose model can be used as the best model to describe the dose-response relationship for hypothyroidism complication.« less

Incorporating Cancer Stem Cells in Radiation Therapy Treatment Response Modeling and the Implication in Glioblastoma Multiforme Treatment Resistance

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

Yu, Victoria Y.; Nguyen, Dan; Pajonk, Frank

Purpose: To perform a preliminary exploration with a simplistic mathematical cancer stem cell (CSC) interaction model to determine whether the tumor-intrinsic heterogeneity and dynamic equilibrium between CSCs and differentiated cancer cells (DCCs) can better explain radiation therapy treatment response with a dual-compartment linear-quadratic (DLQ) model. Methods and Materials: The radiosensitivity parameters of CSCs and DCCs for cancer cell lines including glioblastoma multiforme (GBM), non–small cell lung cancer, melanoma, osteosarcoma, and prostate, cervical, and breast cancer were determined by performing robust least-square fitting using the DLQ model on published clonogenic survival data. Fitting performance was compared with the single-compartment LQ (SLQ) and universalmore » survival curve models. The fitting results were then used in an ordinary differential equation describing the kinetics of DCCs and CSCs in response to 2- to 14.3-Gy fractionated treatments. The total dose to achieve tumor control and the fraction size that achieved the least normal biological equivalent dose were calculated. Results: Smaller cell survival fitting errors were observed using DLQ, with the exception of melanoma, which had a low α/β = 0.16 in SLQ. Ordinary differential equation simulation indicated lower normal tissue biological equivalent dose to achieve the same tumor control with a hypofractionated approach for 4 cell lines for the DLQ model, in contrast to SLQ, which favored 2 Gy per fraction for all cells except melanoma. The DLQ model indicated greater tumor radioresistance than SLQ, but the radioresistance was overcome by hypofractionation, other than the GBM cells, which responded poorly to all fractionations. Conclusion: The distinct radiosensitivity and dynamics between CSCs and DCCs in radiation therapy response could perhaps be one possible explanation for the heterogeneous intertumor response to hypofractionation and in some cases superior outcome from stereotactic ablative radiation therapy. The DLQ model also predicted the remarkable GBM radioresistance, a result that is highly consistent with clinical observations. The radioresistance putatively stemmed from accelerated DCC regrowth that rapidly restored compartmental equilibrium between CSCs and DCCs.« less

Soccer players' fitting perception of different upper boot materials.

PubMed

Olaso Melis, J C; Priego Quesada, J I; Lucas-Cuevas, A G; González García, J C; Puigcerver Palau, S

2016-07-01

The present study assessed the influence of upper boot materials on fitting perception. Twenty players tested three soccer boots only differing in the upper boot material (natural calf leather, natural kangaroo leather and synthetic leather). Players reported fitting perception and preference on specific foot areas using a perceived fitting scale. Ratings were averaged for every foot area. Repeated measures ANOVA was used to analyze the differences between boots. The kangaroo leather boots were perceived tighter and closer to the preferred fitting in general fitting, metatarsals area and instep area. The synthetic leather boots were perceived as the loosest and as the most distant boot from the preferred fitting in medial front area and instep area. In conclusion, the type of upper boot material influences the fitting perception of soccer players. The kangaroo leather was the material whose fitting was perceived closest to the players fitting preference. Copyright © 2016 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Pyrotechnic Tubing Connector

NASA Technical Reports Server (NTRS)

Graves, Thomas J.; Yang, Robert A.

1988-01-01

Tool forms mechanical seal at joint without levers or hydraulic apparatus. Proposed tool intended for use in outer space used on Earth by heavily garbed workers to join tubing in difficult environments. Called Pyrotool, used with Lokring (or equivalent) fittings. Piston slides in cylinder when pushed by gas from detonating pyrotechnic charge. Impulse of piston compresses fittings, sealing around butting ends of tubes.

Comparing Indirect Effects in SEM: A Sequential Model Fitting Method Using Covariance-Equivalent Specifications

ERIC Educational Resources Information Center

Chan, Wai

2007-01-01

In social science research, an indirect effect occurs when the influence of an antecedent variable on the effect variable is mediated by an intervening variable. To compare indirect effects within a sample or across different samples, structural equation modeling (SEM) can be used if the computer program supports model fitting with nonlinear…

The Jig Experiment: Development and Evaluation of a Cultural Dance Active Video Game for Promoting Youth Fitness

ERIC Educational Resources Information Center

Rincker, Meg; Misner, Susan

2017-01-01

School physical education teachers promote fitness by offering children a variety of aerobic activities. Our interdisciplinary team developed a cultural dance active video game (AVG) and tested whether the AVG was equivalent to traditional face-to-face instructor lessons or hybrid instruction at dance mastery, increasing heart rates, and student…

Equivalent Electromagnetic Constants for Microwave Application to Composite Materials for the Multi-Scale Problem

PubMed Central

Fujisaki, Keisuke; Ikeda, Tomoyuki

2013-01-01

To connect different scale models in the multi-scale problem of microwave use, equivalent material constants were researched numerically by a three-dimensional electromagnetic field, taking into account eddy current and displacement current. A volume averaged method and a standing wave method were used to introduce the equivalent material constants; water particles and aluminum particles are used as composite materials. Consumed electrical power is used for the evaluation. Water particles have the same equivalent material constants for both methods; the same electrical power is obtained for both the precise model (micro-model) and the homogeneous model (macro-model). However, aluminum particles have dissimilar equivalent material constants for both methods; different electric power is obtained for both models. The varying electromagnetic phenomena are derived from the expression of eddy current. For small electrical conductivity such as water, the macro-current which flows in the macro-model and the micro-current which flows in the micro-model express the same electromagnetic phenomena. However, for large electrical conductivity such as aluminum, the macro-current and micro-current express different electromagnetic phenomena. The eddy current which is observed in the micro-model is not expressed by the macro-model. Therefore, the equivalent material constant derived from the volume averaged method and the standing wave method is applicable to water with a small electrical conductivity, although not applicable to aluminum with a large electrical conductivity. PMID:28788395

Grain size effect on the permittivity of La1.5Sr0.5NiO4 nanoparticles

NASA Astrophysics Data System (ADS)

Dang Thanh, Tran; Van Hong, Le

2009-09-01

Using the annealing at different temperatures the La1.5Sr0.5NiO4 ceramic samples with different mean grain size were manufactured. Mean grain size () of the samples was evaluated by Warren-Averbach method and their SEM images. The obtained results of both methods are almost the same, changing from 16.2 to 95 nm in dependence on the annealing temperature. The frequency dependence of dielectric constant in the frequency range of (1-13 MHz) was recorded for all samples. The real (ɛ') and the imaginary parts (ɛ") of the permittivity of La1.5Sr0.5NiO4 samples abnormally depend on the frequency, exhibiting a dielectric resonance around 500 kHz. R-L-C in series equivalent-circuit fitted well for the obtained result. It was supposed that there exists magnetic contribution in material that suggests the material is a multiferroic one. Dependence of the (ɛ') on the mean grain size supposed that the colossal dielectric property is an intrinsic behaviour of La1.5Sr0.5NiO4 material.

Weight concerns scale applied to college students: comparison between pencil-and-paper and online formats.

PubMed

Dias, Juliana Chioda Ribeiro; Maroco, João; Campos, Juliana Alvares Duarte Bonini

2015-03-01

Online data collection is becoming increasingly common and has some advantages compared to traditional paper-and-pencil formats, such as reducing loss of data, increasing participants' privacy, and decreasing the effect of social desirability. However, the validity and reliability of this administration format must be established before results can be considered acceptable. The aim of this study was to evaluate the validity, reliability, and equivalence of paper-and-pencil and online versions of the Weight Concerns Scale (WCS) when applied to Brazilian university students. A crossover design was used, and the Portuguese version of the WCS (in both paper-and-pencil and online formats) was completed by 100 college students. The results indicated adequate fit in both formats. The simultaneous fit of data for both groups was excellent, with strong invariance between models. Adequate convergent validity, internal consistency, and mean score equivalence of the WCS in both formats were observed. Thus, the WCS presented adequate reliability and validity in both administration formats, with equivalence/stability between answers.

Characterization of heat transfer in nutrient materials, part 2

NASA Technical Reports Server (NTRS)

Cox, J. E.; Bannerot, R. B.; Chen, C. K.; Witte, L. C.

1973-01-01

A thermal model is analyzed that takes into account phase changes in the nutrient material. The behavior of fluids in low gravity environments is discussed along with low gravity heat transfer. Thermal contact resistance in the Skylab food heater is analyzed. The original model is modified to include: equivalent conductance due to radiation, radial equivalent conductance, wall equivalent conductance, and equivalent heat capacity. A constant wall-temperature model is presented.

Polyimide Prepregs With Improved Tack

NASA Technical Reports Server (NTRS)

Vanucci, R.

1987-01-01

Drape and tack improved without loss of strength. Composites made with PMR-15 (or equivalent) polyimides have gained acceptance as viable engineering materials for high-use-temperature applications. Acceptance due to both thermo-oxidative stability of PMR-15 (or equivalent) and ease which PMR-15 (or equivalent) prepreg materials processed into composite structures.

Insight into collision zone dynamics from topography: numerical modelling results and observations

NASA Astrophysics Data System (ADS)

Bottrill, A. D.; van Hunen, J.; Allen, M. B.

2012-11-01

Dynamic models of subduction and continental collision are used to predict dynamic topography changes on the overriding plate. The modelling results show a distinct evolution of topography on the overriding plate, during subduction, continental collision and slab break-off. A prominent topographic feature is a temporary (few Myrs) basin on the overriding plate after initial collision. This "collisional mantle dynamic basin" (CMDB) is caused by slab steepening drawing, material away from the base of the overriding plate. Also, during this initial collision phase, surface uplift is predicted on the overriding plate between the suture zone and the CMDB, due to the subduction of buoyant continental material and its isostatic compensation. After slab detachment, redistribution of stresses and underplating of the overriding plate cause the uplift to spread further into the overriding plate. This topographic evolution fits the stratigraphy found on the overriding plate of the Arabia-Eurasia collision zone in Iran and south east Turkey. The sedimentary record from the overriding plate contains Upper Oligocene-Lower Miocene marine carbonates deposited between terrestrial clastic sedimentary rocks, in units such as the Qom Formation and its lateral equivalents. This stratigraphy shows that during the Late Oligocene-Early Miocene the surface of the overriding plate sank below sea level before rising back above sea level, without major compressional deformation recorded in the same area. Our modelled topography changes fit well with this observed uplift and subsidence.

30 CFR 75.204 - Roof bolting.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Bearing plates used directly against the mine roof shall be at least 6 inches square or the equivalent... or the equivalent may be used. (3) Bearing plates used with wood or metal materials shall be at least 4 inches square or the equivalent. (4) Wooden materials that are used between a bearing plate and...

30 CFR 75.204 - Roof bolting.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Bearing plates used directly against the mine roof shall be at least 6 inches square or the equivalent... or the equivalent may be used. (3) Bearing plates used with wood or metal materials shall be at least 4 inches square or the equivalent. (4) Wooden materials that are used between a bearing plate and...

30 CFR 75.204 - Roof bolting.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Bearing plates used directly against the mine roof shall be at least 6 inches square or the equivalent... or the equivalent may be used. (3) Bearing plates used with wood or metal materials shall be at least 4 inches square or the equivalent. (4) Wooden materials that are used between a bearing plate and...

30 CFR 75.204 - Roof bolting.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Bearing plates used directly against the mine roof shall be at least 6 inches square or the equivalent... or the equivalent may be used. (3) Bearing plates used with wood or metal materials shall be at least 4 inches square or the equivalent. (4) Wooden materials that are used between a bearing plate and...

Dose equivalent rate constants and barrier transmission data for nuclear medicine facility dose calculations and shielding design.

PubMed

Kusano, Maggie; Caldwell, Curtis B

2014-07-01

A primary goal of nuclear medicine facility design is to keep public and worker radiation doses As Low As Reasonably Achievable (ALARA). To estimate dose and shielding requirements, one needs to know both the dose equivalent rate constants for soft tissue and barrier transmission factors (TFs) for all radionuclides of interest. Dose equivalent rate constants are most commonly calculated using published air kerma or exposure rate constants, while transmission factors are most commonly calculated using published tenth-value layers (TVLs). Values can be calculated more accurately using the radionuclide's photon emission spectrum and the physical properties of lead, concrete, and/or tissue at these energies. These calculations may be non-trivial due to the polyenergetic nature of the radionuclides used in nuclear medicine. In this paper, the effects of dose equivalent rate constant and transmission factor on nuclear medicine dose and shielding calculations are investigated, and new values based on up-to-date nuclear data and thresholds specific to nuclear medicine are proposed. To facilitate practical use, transmission curves were fitted to the three-parameter Archer equation. Finally, the results of this work were applied to the design of a sample nuclear medicine facility and compared to doses calculated using common methods to investigate the effects of these values on dose estimates and shielding decisions. Dose equivalent rate constants generally agreed well with those derived from the literature with the exception of those from NCRP 124. Depending on the situation, Archer fit TFs could be significantly more accurate than TVL-based TFs. These results were reflected in the sample shielding problem, with unshielded dose estimates agreeing well, with the exception of those based on NCRP 124, and Archer fit TFs providing a more accurate alternative to TVL TFs and a simpler alternative to full spectral-based calculations. The data provided by this paper should assist in improving the accuracy and tractability of dose and shielding calculations for nuclear medicine facility design.

49 CFR 178.507 - Standards for plywood drums.

Code of Federal Regulations, 2013 CFR

2013-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR PACKAGINGS Non... effectiveness of the drum for the purpose intended. A material other than plywood, of at least equivalent..., lids must be lined with kraft paper or some other equivalent material which must be securely fastened...

Computational micromechanics of woven composites

NASA Technical Reports Server (NTRS)

Hopkins, Dale A.; Saigal, Sunil; Zeng, Xiaogang

1991-01-01

The bounds on the equivalent elastic material properties of a composite are presently addressed by a unified energy approach which is valid for both unidirectional and 2D and 3D woven composites. The unit cell considered is assumed to consist, first, of the actual composite arrangement of the fibers and matrix material, and then, of an equivalent pseudohomogeneous material. Equating the strain energies due to the two arrangements yields an estimate of the upper bound for the material equivalent properties; successive increases in the order of displacement field that is assumed in the composite arrangement will successively produce improved upper bound estimates.

Final report on EURAMET.QM-K12: EURAMET key comparison on the determination of the mass fraction of creatinine in serum

NASA Astrophysics Data System (ADS)

Bell, David; Hopley, Chris; Ellison, Stephen L. R.; O'Connor, Gavin

2013-01-01

Creatinine is a well-known marker for the evaluation of kidney function. Its routine measurement is undertaken by many clinical laboratories and comparable results over distance and time are required for effective diagnosis. To address this need many National Measurement Institutes (or designated institutes) provide services in this area via the provision of higher order standards or reference measurements. The organic analysis working group of the consultative committee for amount of substance have conducted two previous key comparisons to assess the equivalence of institutes who provide such services. The purpose of this study was to enable institutes who missed the previous studies to demonstrate their capability for characterizing serum materials containing 1 µg/g to 100 µg/g of creatinine. The study material consisted of two lyophilized serum samples which were used in an external quality control proficiency testing scheme. No target values were available for these materials and all participants reported results within the one month timeframe given for analysis. Five institutes participated in the key study and a single institute submitted results for the parallel pilot study. All participants in the key study used isotope dilution with either gas or liquid chromatography coupled with mass spectrometry. The pilot study laboratory used a novel isotope dilution surface-enhanced Raman spectroscopy method. The comparison reference value for each material was set as the mean of all results submitted by those participating in the key study. The choice of the reference value estimator was constrained as it was deemed more appropriate to treat the data in a similar manner to CCQM-K12 if the relative degrees of equivalence were to be compared. This resulted in reference values of (54.27 ± 0.72) µg/g and (38.01 ± 0.42) µg/g for the two separate materials. The relative degrees of equivalence were calculated and these were compared with the relative degrees of equivalence of participants in CCQM-K12. The range of participants' results in EURAMET.QM-K12 for both levels (2% and 3% respectively for materials A and B) was greater than the 1% achieved in CCQM-K12. However, it was concluded that this study was suitable to support CMCs for creatinine in serum for 1 µg/g to 100 µg/g with uncertainties at the 1% to 1.5% level. This was found to be fit for purpose and consistent with the majority of CMCs currently approved. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Explosive materials equivalency, test methods and evaluation

NASA Technical Reports Server (NTRS)

Koger, D. M.; Mcintyre, F. L.

1980-01-01

Attention is given to concepts of explosive equivalency of energetic materials based on specific airblast parameters. A description is provided of a wide bandwidth high accuracy instrumentation system which has been used extensively in obtaining pressure time profiles of energetic materials. The object of the considered test method is to determine the maximum output from the detonation of explosive materials in terms of airblast overpressure and positive impulse. The measured pressure and impulse values are compared with known characteristics of hemispherical TNT data to determine the equivalency of the test material in relation to TNT. An investigation shows that meaningful comparisons between various explosives and a standard reference material such as TNT should be based upon the same parameters. The tests should be conducted under the same conditions.

Life Cycle Assessment for Chemical Agent Resistant Coating.

DTIC Science & Technology

1996-09-01

994) document to develop HVs from 1 to 2.5. The final equivalency factor for a chemical was based on the formula: Equivalency Factor = (toxicity HV...applicable to the development of processes/procedures and their implementation, likely would fit better with a true LCA- based design exercise for a product...Johnny Springer, Jr., National Risk Management Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency

On-line monitoring of the crystallization process: relationship between crystal size and electrical impedance spectra

NASA Astrophysics Data System (ADS)

Zhao, Yanlin; Yao, Jun; Wang, Mi

2016-07-01

On-line monitoring of crystal size in the crystallization process is crucial to many pharmaceutical and fine-chemical industrial applications. In this paper, a novel method is proposed for the on-line monitoring of the cooling crystallization process of L-glutamic acid (LGA) using electrical impedance spectroscopy (EIS). The EIS method can be used to monitor the growth of crystal particles relying on the presence of an electrical double layer on the charged particle surface and the polarization of double layer under the excitation of alternating electrical field. The electrical impedance spectra and crystal size were measured on-line simultaneously by an impedance analyzer and focused beam reflectance measurement (FBRM), respectively. The impedance spectra were analyzed using the equivalent circuit model and the equivalent circuit elements in the model can be obtained by fitting the experimental data. Two equivalent circuit elements, including capacitance (C 2) and resistance (R 2) from the dielectric polarization of the LGA solution and crystal particle/solution interface, are in relation with the crystal size. The mathematical relationship between the crystal size and the equivalent circuit elements can be obtained by a non-linear fitting method. The function can be used to predict the change of crystal size during the crystallization process.

Simulated effects of YY-male stocking and manual suppression for eradicating nonnative Brook Trout populations

USGS Publications Warehouse

Schill, Daniel J.; Meyer, Kevin A.; Hansen, Michael J.

2017-01-01

Eradication of nonnative Brook Trout Salvelinus fontinalis populations is difficult to achieve with standard techniques, such as electrofishing removal or piscicides; new approaches are needed. A novel concept is to stock “supermale” hatchery fish with wild conspecifics. Supermales (MYY) have two Y-chromosomes, resulting in offspring that are all males; over time, successful supermale reproduction could eradicate the wild population. We constructed an age-structured stochastic model to investigate the effects of manually suppressing wild fish and stocking MYY fingerlings on the long-term viability of hypothetical nonnative Brook Trout populations. In streams, an annual stocking rate of supermales equivalent to 50% of wild age-0 Brook Trout density combined with an annual selective suppression rate equivalent to 50% of wild Brook Trout density resulted in a time to extirpation of only 2–4 years if supermale fitness was equivalent to wild male fitness. However, time to extirpation in streams was 5–15 years if supermale fitness was 80% lower than wild male fitness. In alpine lakes, higher supermale stocking rates and nonselective gillnetting were required to eradicate Brook Trout populations. If supermales were assumed to be as fit as wild males, however, any supermale stocking rate greater than 49% in alpine lakes or 60% in streams achieved eradication in 10 years or less, regardless of the suppression rate. Because manual suppression and the stocking of MYY fingerlings can readily be conducted at the levels assumed in our simulations, use of such an integrated pest management (IPM) approach could extirpate undesirable Brook Trout populations within reasonably short periods of time. Given the recent successful development of an MYY Brook Trout broodstock capable of producing large numbers of MYY fingerlings and given the positive results of the present simulations for both streams and alpine lakes, field testing of MYY stocking is warranted within an IPM program that includes manual suppression for eradicating undesirable Brook Trout populations.

Influential Nonegligible Parameters under the Search Linear Model.

DTIC Science & Technology

1986-04-25

lack of fit as wi 2 SSL0F(1 ) - I n u~ -(M) (12) and the sum of squares due to pure error as SSPE - I I (Y V-2 (13) For I 1,.,2) we define F(i) SSL0F...SSE (I) Noting that the numerator on the RHS of the above expression does not depend on i, we get the equivalence of (a) and (b). Again, SSE ) SSPE ...SSLOFM I and SSPE does not depend on i. Therefore (a) and (c) are equivalent. - From (14), the equivalence of (c) and (d) is clear. From (3), (6

Quantitative evaluation method for nonlinear characteristics of piezoelectric transducers under high stress with complex nonlinear elastic constant

NASA Astrophysics Data System (ADS)

Miyake, Susumu; Kasashima, Takashi; Yamazaki, Masato; Okimura, Yasuyuki; Nagata, Hajime; Hosaka, Hiroshi; Morita, Takeshi

2018-07-01

The high power properties of piezoelectric transducers were evaluated considering a complex nonlinear elastic constant. The piezoelectric LCR equivalent circuit with nonlinear circuit parameters was utilized to measure them. The deformed admittance curve of piezoelectric transducers was measured under a high stress and the complex nonlinear elastic constant was calculated by curve fitting. Transducers with various piezoelectric materials, Pb(Zr,Ti)O3, (K,Na)NbO3, and Ba(Zr,Ti)O3–(Ba,Ca)TiO3, were investigated by the proposed method. The measured complex nonlinear elastic constant strongly depends on the linear elastic and piezoelectric constants. This relationship indicates that piezoelectric high power properties can be controlled by modifying the linear elastic and piezoelectric constants.

Magnetically tunable graphene-based reflector under linear polarized incidence at room temperature

NASA Astrophysics Data System (ADS)

Yang, Liang; Tian, Jing; Giddens, Henry; Poumirol, Jean-Marie; Wu, JingBo; Kuzmenko, Alexey B.; Hao, Yang

2018-04-01

At the terahertz spectrum, the 2D material graphene has diagonal and Hall conductivities in the presence of a magnetic field. These peculiar properties provide graphene-based structures with a magnetically tunable response to electromagnetic waves. In this work, the absolute reflection intensity was measured for a graphene-based reflector illuminated by linearly polarized incident waves at room temperature, which demonstrated the intensity modulation depth (IMD) under different magnetostatic biases by up to 15%. Experimental data were fitted and analyzed by a modified equivalent circuit model. In addition, as an important phenomenon of the graphene gyrotropic response, Kerr rotation is discussed according to results achieved from full-wave simulations. It is concluded that the IMD is reduced for the best Kerr rotation in the proposed graphene-based reflector.

Energy absorption buildup factors of human organs and tissues at energies and penetration depths relevant for radiotherapy and diagnostics

PubMed Central

Hanagodimath, S. M.; Gerward, L.

2011-01-01

Energy absorption geometric progression (GP) fitting parameters and the corresponding buildup factors have been computed for human organs and tissues, such as adipose tissue, blood (whole), cortical bone, brain (grey/white matter), breast tissue, eye lens, lung tissue, skeletal muscle, ovary, testis, soft tissue, and soft tissue (4‐component), for the photon energy range 0.015–15 MeV and for penetration depths up to 40 mfp (mean free path). The chemical composition of human organs and tissues is seen to influence the energy absorption buildup factors. It is also found that the buildup factor of human organs and tissues changes significantly with the change of incident photon energy and effective atomic number, Zeff. These changes are due to the dominance of different photon interaction processes in different energy regions and different chemical compositions of human organs and tissues. With the proper knowledge of buildup factors of human organs and tissues, energy absorption in the human body can be carefully controlled. The present results will help in estimating safe dose levels for radiotherapy patients and also useful in diagnostics and dosimetry. The tissue‐equivalent materials for skeletal muscle, adipose tissue, cortical bone, and lung tissue are also discussed. It is observed that water and MS20 are good tissue equivalent materials for skeletal muscle in the extended energy range. PACS numbers: 32.80‐t, 87.53‐j, 78.70‐g, 78.70‐Ck PMID:22089011

Experimental Design for a Sponge-Wipe Study to Relate the Recovery Efficiency and False Negative Rate to the Concentration of a Bacillus anthracis Surrogate for Six Surface Materials

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

Piepel, Gregory F.; Amidan, Brett G.; Krauter, Paula

2010-12-16

Two concerns were raised by the Government Accountability Office following the 2001 building contaminations via letters containing Bacillus anthracis (BA). These included the: 1) lack of validated sampling methods, and 2) need to use statistical sampling to quantify the confidence of no contamination when all samples have negative results. Critical to addressing these concerns is quantifying the probability of correct detection (PCD) (or equivalently the false negative rate FNR = 1 - PCD). The PCD/FNR may depend on the 1) method of contaminant deposition, 2) surface concentration of the contaminant, 3) surface material being sampled, 4) sample collection method, 5)more » sample storage/transportation conditions, 6) sample processing method, and 7) sample analytical method. A review of the literature found 17 laboratory studies that focused on swab, wipe, or vacuum samples collected from a variety of surface materials contaminated by BA or a surrogate, and used culture methods to determine the surface contaminant concentration. These studies quantified performance of the sampling and analysis methods in terms of recovery efficiency (RE) and not PCD/FNR (which left a major gap in available information). Quantifying the PCD/FNR under a variety of conditions is a key aspect of validating sample and analysis methods, and also for calculating the confidence in characterization or clearance decisions based on a statistical sampling plan. A laboratory study was planned to partially fill the gap in PCD/FNR results. This report documents the experimental design developed by Pacific Northwest National Laboratory and Sandia National Laboratories (SNL) for a sponge-wipe method. The study will investigate the effects on key response variables from six surface materials contaminated with eight surface concentrations of a BA surrogate (Bacillus atrophaeus). The key response variables include measures of the contamination on test coupons of surface materials tested, contamination recovered from coupons by sponge-wipe samples, RE, and PCD/FNR. The experimental design involves 16 test runs, to be performed in two blocks of eight runs. Three surface materials (stainless steel, vinyl tile, and ceramic tile) were tested in the first block, while three other surface materials (plastic, painted wood paneling, and faux leather) will be tested in the second block. The eight surface concentrations of the surrogate were randomly assigned to test runs within each block. Some of the concentrations will be very low and may present challenges for deposition, sampling, and analysis. However, such tests are needed to investigate RE and PCD/FNR over the full range of concentrations of interest. In each run, there will be 10 test coupons of each of the three surface materials. A positive control sample will be generated prior to each test sample. The positive control results will be used to 1) calculate RE values for the wipe sampling and analysis method, and 2) fit RE- and PCD-concentration equations, for each of the six surface materials. Data analyses will support 1) estimating the PCD for each combination of contaminant concentration and surface material, 2) estimating the surface concentrations and their uncertainties of the contaminant for each combination of concentration and surface material, 3) estimating RE (%) and their uncertainties for each combination of contaminant concentration and surface material, 4) fitting PCD-concentration and RE-concentration equations for each of the six surface materials, 5) assessing goodness-of-fit of the equations, and 6) quantifying the uncertainty in PCD and RE predictions made with the fitted equations.« less

VizieR Online Data Catalog: DIB in VLT-FLAMES Tarantula Survey (van Loon+, 2013)

NASA Astrophysics Data System (ADS)

van Loon, J. T.; Bailey, M.; Tatton, B. L.; Maíz Apellániz, J.; Crowther, P. A.; de Koter, A.; Evans, C. J.; Henault-Brunet, V.; Howarth, I. D.; Richter, P.; Sana, H.; Simon-Diaz, S.; Taylor, W.; Walborn, N. R.

2012-11-01

Equivalent widths of the 4428, 5780, 5797 and 6614 Diffuse Interstellar Bands (DIBs) were measured for up to 800 OB-type stars in the Tarantula Nebula (30 Doradus, containing the massive compact star cluster R136) in the Large Magellanic Cloud (LMC). The Galactic foreground and LMC components were fitted simultaneously, with Lorentzians for the 4428 DIB and Gaussians for the other DIBs. All fits were inspected by eye, and a flag was reset to zero if the fit was rejected. (3 data files).

Effects of Nordic walking training on exercise capacity and fitness in men participating in early, short-term inpatient cardiac rehabilitation after an acute coronary syndrome--a controlled trial.

PubMed

Kocur, Piotr; Deskur-Smielecka, Ewa; Wilk, Malgorzata; Dylewicz, Piotr

2009-11-01

To investigate the effects of Nordic Walking training supplemental to a standard, early rehabilitation programme on exercise capacity and physical fitness in men after an acute coronary syndrome. A controlled trial. Cardiac rehabilitation service of a provincial hospital. Eighty men 2-3 weeks after an acute coronary syndrome, with good exercise tolerance. Three-week, inpatient cardiac rehabilitation programme (control group) supplemented with Nordic Walking (Nordic Walking group), or with traditional walking training (walking training group). Exercise capacity was assessed as peak energy cost (in metabolic equivalents) in symptom-limited treadmill exercise test, and physical fitness with the Fullerton Functional Fitness Test. Exercise capacity after the rehabilitation programme was higher in the Nordic Walking group than in the control group (10.8 +/- 1.8 versus 9.2 +/- 2.2 metabolic equivalents, P =0.025). The improvement in exercise capacity in the Nordic Walking group was higher than in the control group (1.8 +/- 1.5 versus 0.7 +/- 1.4 metabolic equivalents, P =0.002). In contrast to the control group, the results of all components of the Fullerton test improved in the Nordic Walking and walking training groups. After the programme, lower body endurance, and dynamic balance were significantly better in the Nordic Walking group in comparison with the walking training and control groups, and upper body endurance was significantly better in the Nordic Walking and walking training groups than in the control group. Nordic Walking may improve exercise capacity, lower body endurance and coordination of movements in patients with good exercise tolerance participating in early, short-term rehabilitation after an acute coronary syndrome.

Maximal exercise testing variables and 10-year survival: fitness risk score derivation from the FIT Project.

PubMed

Ahmed, Haitham M; Al-Mallah, Mouaz H; McEvoy, John W; Nasir, Khurram; Blumenthal, Roger S; Jones, Steven R; Brawner, Clinton A; Keteyian, Steven J; Blaha, Michael J

2015-03-01

To determine which routinely collected exercise test variables most strongly correlate with survival and to derive a fitness risk score that can be used to predict 10-year survival. This was a retrospective cohort study of 58,020 adults aged 18 to 96 years who were free of established heart disease and were referred for an exercise stress test from January 1, 1991, through May 31, 2009. Demographic, clinical, exercise, and mortality data were collected on all patients as part of the Henry Ford ExercIse Testing (FIT) Project. Cox proportional hazards models were used to identify exercise test variables most predictive of survival. A "FIT Treadmill Score" was then derived from the β coefficients of the model with the highest survival discrimination. The median age of the 58,020 participants was 53 years (interquartile range, 45-62 years), and 28,201 (49%) were female. Over a median of 10 years (interquartile range, 8-14 years), 6456 patients (11%) died. After age and sex, peak metabolic equivalents of task and percentage of maximum predicted heart rate achieved were most highly predictive of survival (P<.001). Subsequent addition of baseline blood pressure and heart rate, change in vital signs, double product, and risk factor data did not further improve survival discrimination. The FIT Treadmill Score, calculated as [percentage of maximum predicted heart rate + 12(metabolic equivalents of task) - 4(age) + 43 if female], ranged from -200 to 200 across the cohort, was near normally distributed, and was found to be highly predictive of 10-year survival (Harrell C statistic, 0.811). The FIT Treadmill Score is easily attainable from any standard exercise test and translates basic treadmill performance measures into a fitness-related mortality risk score. The FIT Treadmill Score should be validated in external populations. Copyright © 2015 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Quasi-Fermi level splitting and sub-bandgap absorptivity from semiconductor photoluminescence

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

Katahara, John K.; Hillhouse, Hugh W., E-mail: h2@uw.edu

A unified model for the direct gap absorption coefficient (band-edge and sub-bandgap) is developed that encompasses the functional forms of the Urbach, Thomas-Fermi, screened Thomas-Fermi, and Franz-Keldysh models of sub-bandgap absorption as specific cases. We combine this model of absorption with an occupation-corrected non-equilibrium Planck law for the spontaneous emission of photons to yield a model of photoluminescence (PL) with broad applicability to band-band photoluminescence from intrinsic, heavily doped, and strongly compensated semiconductors. The utility of the model is that it is amenable to full-spectrum fitting of absolute intensity PL data and yields: (1) the quasi-Fermi level splitting, (2) themore » local lattice temperature, (3) the direct bandgap, (4) the functional form of the sub-bandgap absorption, and (5) the energy broadening parameter (Urbach energy, magnitude of potential fluctuations, etc.). The accuracy of the model is demonstrated by fitting the room temperature PL spectrum of GaAs. It is then applied to Cu(In,Ga)(S,Se){sub 2} (CIGSSe) and Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) to reveal the nature of their tail states. For GaAs, the model fit is excellent, and fitted parameters match literature values for the bandgap (1.42 eV), functional form of the sub-bandgap states (purely Urbach in nature), and energy broadening parameter (Urbach energy of 9.4 meV). For CIGSSe and CZTSSe, the model fits yield quasi-Fermi leveling splittings that match well with the open circuit voltages measured on devices made from the same materials and bandgaps that match well with those extracted from EQE measurements on the devices. The power of the exponential decay of the absorption coefficient into the bandgap is found to be in the range of 1.2 to 1.6, suggesting that tunneling in the presence of local electrostatic potential fluctuations is a dominant factor contributing to the sub-bandgap absorption by either purely electrostatic (screened Thomas-Fermi) or a photon-assisted tunneling mechanism (Franz-Keldysh). A Gaussian distribution of bandgaps (local E{sub g} fluctuation) is found to be inconsistent with the data. The sub-bandgap absorption of the CZTSSe absorber is found to be larger than that for CIGSSe for materials that yield roughly equivalent photovoltaic devices (8% efficient). Further, it is shown that fitting only portions of the PL spectrum (e.g., low energy for energy broadening parameter and high energy for quasi-Fermi level splitting) may lead to significant errors for materials with substantial sub-bandgap absorption and emission.« less

Computer simulations and models for the performance characteristics of spectrally equivalent X-ray beams in medical diagnostic radiology

PubMed Central

Okunade, Akintunde A.

2007-01-01

In order to achieve uniformity in radiological imaging, it is recommended that the concept of equivalence in shape (quality) and size (quantity) of clinical Xray beams should be used for carrying out the comparative evaluation of image and patient dose. When used under the same irradiation geometry, X-ray beams that are strictly or relatively equivalent in terms of shape and size will produce identical or relatively identical image quality and patient dose. Simple mathematical models and software program EQSPECT.FOR were developed for the comparative evaluation of the performance characteristics in terms of contrast (C), contrast to noise ratio (CNR) and figure-of-merit (FOM = CNR2/DOSE) for spectrally equivalent beams transmitted through filter materials referred to as conventional and k-edged. At the same value of operating potential (kVp), results show that spectrally equivalent beam transmitted through conventional filter with higher atomic number (Z-value) in comparison with that transmitted through conventional filter with lower Z-value resulted in the same value of C and FOM. However, in comparison with the spectrally equivalent beam transmitted through filter of lower Z-value, the beam through filter of higher Z-value produced higher value of CNR and DOSE at equal tube loading (mAs) and kVp. Under the condition of equivalence of spectrum, at scaled (or reduced) tube loading and same kVp, filter materials of higher Z-value can produce the same values of C, CNR, DOSE and FOM as filter materials of lower Z-value. Unlike the case of comparison of spectrally equivalent beam transmitted through one conventional filter and that through another conventional filter, it is not possible to derive simple mathematical formulations for the relative performance of spectrally equivalent beam transmitted through a given conventional filter material and that through kedge filter material. PMID:21224928

46 CFR 108.105 - Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations...

Code of Federal Regulations, 2010 CFR

2010-10-01

....105 Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations, and tests. (a) Where this subchapter requires a particular fitting, material, apparatus, equipment... satisfaction of the Commandant that the use of any particular equipment, apparatus, arrangement, or test is...

46 CFR 108.105 - Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations...

Code of Federal Regulations, 2011 CFR

2011-10-01

....105 Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations, and tests. (a) Where this subchapter requires a particular fitting, material, apparatus, equipment... satisfaction of the Commandant that the use of any particular equipment, apparatus, arrangement, or test is...

Anelastic characterization of soft poroelastic materials by anelastography

NASA Astrophysics Data System (ADS)

Flores B, Carolina; Ammann, Jean Jacques; Rivera, Ricardo

2008-11-01

This paper presents the ID characterization of the local anelastic strain determined in soft poroelastic materials through acoustic scattering in a creep test configuration. Backscattering signals are obtained at successive times in a specimen submitted to a constant stress, applied coaxially to the acoustic beam of a 5 MHz ultrasonic transducer operated in pulse-echo mode. The local displacement is measured by determining the local shift between the RF traces by performing a running cross-correlation operation between equivalent segments extracted from two pairs of RF traces. The local strain the in the specimen is obtained as the displacement gradient. The method has been implemented on biphasic porous materials that present poroelastic behaviors such as synthetic latex sponges impregnated with viscous liquids. The strain/time curves have been interpreted through a continuous bimodal anelastic model (CBA), composed of an infinite set of Kelvin-Voigt cells connected in series with an elastic spring. The fit of an experimental strain/time curve selected at a specific depth through the CBA model allow characterizing the local anelastic behavior through a set of 7 characteristics parameters for the specimen at this location: three short-term and three long-term anelastic parameters and one elastic constant.

Analysis of multi-layered films. [determining dye densities by applying a regression analysis to the spectral response of the composite transparency

NASA Technical Reports Server (NTRS)

Scarpace, F. L.; Voss, A. W.

1973-01-01

Dye densities of multi-layered films are determined by applying a regression analysis to the spectral response of the composite transparency. The amount of dye in each layer is determined by fitting the sum of the individual dye layer densities to the measured dye densities. From this, dye content constants are calculated. Methods of calculating equivalent exposures are discussed. Equivalent exposures are a constant amount of energy over a limited band-width that will give the same dye content constants as the real incident energy. Methods of using these equivalent exposures for analysis of photographic data are presented.

Structural evaluation of asphalt pavements with full-depth reclaimed base.

DOT National Transportation Integrated Search

2012-12-01

Currently, MnDOT pavement design recommends granular equivalency, GE = 1.0 for non-stabilized full-depth : reclamation (FDR) material, which is equivalent to class 5 material. For stabilized full-depth reclamation (SFDR), : there was no guideline for...

Heart rate recovery, exercise capacity, and mortality risk in male veterans.

PubMed

Kokkinos, Peter; Myers, Jonathan; Doumas, Michael; Faselis, Charles; Pittaras, Andreas; Manolis, Athanasios; Kokkinos, John Peter; Narayan, Puneet; Papademetriou, Vasilios; Fletcher, Ross

2012-04-01

Both impaired heart rate recovery (HRR) and low fitness are associated with higher mortality risk. In addition, HRR is influenced by fitness status. The interaction between HRR, mortality, and fitness has not been clearly defined. Thus, we sought to evaluate the association between HRR and all-cause mortality and to assess the effects of fitness on this association. Treadmill exercise testing was performed in 5974 male veterans for clinical reasons at two Veterans Affairs Medical Centers (Washington, DC and Palo Alto, CA). HRR was calculated at 1 and 2 min of recovery. All-cause mortality was determined over a mean 6.2-year follow-up period. Mortality risk was significantly and inversely associated with HRR, only at 2 min. A cut-off value of 14 beats/min at 2 min recovery was the strongest predictor of mortality for the cohort (hazard ratio = 2.4; CI 1.6-3.5). The mortality risk was overestimated when exercise capacity was not considered. When both low fitness and low HRR were present (≤6 metabolic equivalents and ≤14 beats/min), mortality risk was approximately seven-fold higher compared to the High-fit + High-HRR group (>6 metabolic equivalents and >14 beats/min). HRR at 2 min post exercise is strongly and inversely associated with all-cause mortality. Exercise capacity affects HRR-associated mortality substantially and should be considered when applying HRR to estimate mortality.

Correlation between adenoma detection rate in colonoscopy- and fecal immunochemical testing-based colorectal cancer screening programs.

PubMed

Cubiella, Joaquín; Castells, Antoni; Andreu, Montserrat; Bujanda, Luis; Carballo, Fernando; Jover, Rodrigo; Lanas, Ángel; Morillas, Juan Diego; Salas, Dolores; Quintero, Enrique

2017-03-01

The adenoma detection rate (ADR) is the main quality indicator of colonoscopy. The ADR recommended in fecal immunochemical testing (FIT)-based colorectal cancer screening programs is unknown. Using the COLONPREV (NCT00906997) study dataset, we performed a post-hoc analysis to determine if there was a correlation between the ADR in primary and work-up colonoscopy, and the equivalent figure to the minimal 20% ADR recommended. Colonoscopy was performed in 5722 individuals: 5059 as primary strategy and 663 after a positive FIT result (OC-Sensor™; cut-off level 15 µg/g of feces). We developed a predictive model based on a multivariable lineal regression analysis including confounding variables. The median ADR was 31% (range, 14%-51%) in the colonoscopy group and 55% (range, 21%-83%) in the FIT group. There was a positive correlation in the ADR between primary and work-up colonoscopy (Pearson's coefficient 0.716; p  < 0.001). ADR in the FIT group was independently related to ADR in the colonoscopy group: regression coefficient for colonoscopy ADR, 0.71 ( p  = 0.009); sex, 0.09 ( p  = 0.09); age, 0.3 ( p  = 0.5); and region 0.00 ( p  = 0.9). The equivalent figure to the 20% ADR was 45% (95% confidence interval, 35%-56%). ADR in primary and work-up colonoscopy of a FIT-positive result are positively and significantly correlated.

Correlation between adenoma detection rate in colonoscopy- and fecal immunochemical testing-based colorectal cancer screening programs

PubMed Central

Castells, Antoni; Andreu, Montserrat; Bujanda, Luis; Carballo, Fernando; Jover, Rodrigo; Lanas, Ángel; Morillas, Juan Diego; Salas, Dolores; Quintero, Enrique

2016-01-01

Background The adenoma detection rate (ADR) is the main quality indicator of colonoscopy. The ADR recommended in fecal immunochemical testing (FIT)-based colorectal cancer screening programs is unknown. Methods Using the COLONPREV (NCT00906997) study dataset, we performed a post-hoc analysis to determine if there was a correlation between the ADR in primary and work-up colonoscopy, and the equivalent figure to the minimal 20% ADR recommended. Colonoscopy was performed in 5722 individuals: 5059 as primary strategy and 663 after a positive FIT result (OC-Sensor™; cut-off level 15 µg/g of feces). We developed a predictive model based on a multivariable lineal regression analysis including confounding variables. Results The median ADR was 31% (range, 14%–51%) in the colonoscopy group and 55% (range, 21%–83%) in the FIT group. There was a positive correlation in the ADR between primary and work-up colonoscopy (Pearson’s coefficient 0.716; p < 0.001). ADR in the FIT group was independently related to ADR in the colonoscopy group: regression coefficient for colonoscopy ADR, 0.71 (p = 0.009); sex, 0.09 (p = 0.09); age, 0.3 (p = 0.5); and region 0.00 (p = 0.9). The equivalent figure to the 20% ADR was 45% (95% confidence interval, 35%–56%). Conclusions ADR in primary and work-up colonoscopy of a FIT-positive result are positively and significantly correlated. PMID:28344793

Autism as the Low-Fitness Extreme of a Parentally Selected Fitness Indicator.

PubMed

Shaner, Andrew; Miller, Geoffrey; Mintz, Jim

2008-12-01

Siblings compete for parental care and feeding, while parents must allocate scarce resources to those offspring most likely to survive and reproduce. This could cause offspring to evolve traits that advertise health, and thereby attract parental resources. For example, experimental evidence suggests that bright orange filaments covering the heads of North American coot chicks may have evolved for this fitness-advertising purpose. Could any human mental disorders be the equivalent of dull filaments in coot chicks-low-fitness extremes of mental abilities that evolved as fitness indicators? One possibility is autism. Suppose that the ability of very young children to charm their parents evolved as a parentally selected fitness indicator. Young children would vary greatly in their ability to charm parents, that variation would correlate with underlying fitness, and autism could be the low-fitness extreme of this variation. This view explains many seemingly disparate facts about autism and leads to some surprising and testable predictions.

Theoretical prediction on corrugated sandwich panels under bending loads

NASA Astrophysics Data System (ADS)

Shu, Chengfu; Hou, Shujuan

2018-05-01

In this paper, an aluminum corrugated sandwich panel with triangular core under bending loads was investigated. Firstly, the equivalent material parameters of the triangular corrugated core layer, which could be considered as an orthotropic panel, were obtained by using Castigliano's theorem and equivalent homogeneous model. Secondly, contributions of the corrugated core layer and two face panels were both considered to compute the equivalent material parameters of the whole structure through the classical lamination theory, and these equivalent material parameters were compared with finite element analysis solutions. Then, based on the Mindlin orthotropic plate theory, this study obtain the closed-form solutions of the displacement for a corrugated sandwich panel under bending loads in specified boundary conditions, and parameters study and comparison by the finite element method were executed simultaneously.

Three-Dimensional Digital Evaluation of the Fit of Endocrowns Fabricated from Different CAD/CAM Materials.

PubMed

Zimmermann, Moritz; Valcanaia, Andre; Neiva, Gisele; Mehl, Albert; Fasbinder, Dennis

2018-03-06

A wide variety of CAD/CAM materials are available for single-tooth restorations. CAD/CAM material characteristics are different and may influence CAM fabrication accuracy. There is no study investigating the influence of different CAD/CAM materials on the final fit of the restoration. The aim of this study was to evaluate the fit of endocrowns fabricated from different CAD/CAM materials using a new 3D evaluation method with an intraoral scanning system. The null hypothesis was that there are no significant differences for the fitting accuracy of different CAD/CAM materials. Preparation for an endocrown was performed on a maxillary right first molar on a typodont, and restorations were fabricated with a chairside CAD/CAM system (CEREC Omnicam, MCXL). Three groups using three different CAD/CAM materials were established (each n = 10): zirconia-reinforced lithium silicate ceramic (Celtra Duo; CD), leucite-reinforced silicate ceramic (Empress CAD; EM), resin nanoceramic (Lava Ultimate; LU). A 3D digital measurement technique (OraCheck, Cyfex AG) using an intraoral scanner (CEREC Omnicam) was used to measure the difference in fit between the three materials for a master endocrown preparation. The preparation scan and the endocrown fit scan were matched with special difference analysis software OraCheck. Three areas were selected for fitting accuracy measurements: margin (MA), axial (AX), occlusal (OC). Statistical analysis was performed using 80% percentile, one-way ANOVA, and post-hoc Scheffé test. Significance level was set to p = 0.05. Results varied from best 88.9 ± 7.7 μm for marginal fit of resin nanoceramic restorations (LU_MA) to worst 182.3 ± 24.0 μm for occlusal fit of zirconia-reinforced lithium silicate restorations (CD_OC). Statistically significant differences were found both within and among the test groups. Group CD performed statistically significantly different from group LU for marginal fit (MA) and axial fit (AX) (p < 0.05). For occlusal fit (OC), no statistically significant differences were found within all three test groups (p > 0.05). Deviation pattern for differences was visually analyzed with a color-coded scheme for each restoration. Statistically significant differences were found for different CAD/CAM materials if the CAM procedure was identical. Within the limitations of this study, the choice of CAD/CAM material may influence the fitting accuracy of CAD/CAM-fabricated restorations. © 2018 by the American College of Prosthodontists.

Nanostructured gold and platinum electrodes on silicon structures for biosensing

NASA Astrophysics Data System (ADS)

Ogurtsov, V. I.; Sheehan, M. M.

2005-01-01

Gold and platinum metal electrodes on Si/SiO2 having undergone anisotropic potassium hydroxide (KOH) etch treatment are considered. This treatment etches at different rates and directions in the material resulting in creation of numerous pyramid shaped holes in the silicon substrate. This surface is used to make metal electrodes with increased electrode efficiency. The electrodes can serve as the sensors or as the sensor substrates (for surface polymer modification) and because both gold and platinum are inert they have applications for food safety biosensing. Wine, an economically significant food product, was chosen as a matrix, and impedance spectroscopy (EIS) was selected as a method of investigation of electrode behaviour. Based on results of EIS, different complexity equivalent circuits were determined by applying fitting mean square root optimisation of sensor complex impedance measurements.

77 FR 5305 - Hazardous Materials: Special Permit and Approval Applicant Fitness Determinations; Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-02

.... PHMSA-2011-0283; Notice No. 12-2] Hazardous Materials: Special Permit and Approval Applicant Fitness... conduct a public meeting to discuss Special Permit and Approval applicant fitness determinations. The... used when determining an applicant's minimum level of fitness. DATES: Public Meeting: Wednesday...

BioProgrammable One, Two, and Three Dimensional Materials

DTIC Science & Technology

2017-01-18

or three- dimensional architectures. The Mirkin group has used DNA-functionalized nanoparticles as “programmable atom equivalents (PAEs)” as material...with electron beam lithography to simultaneously control material structure at the nano- and macroscopic length scales. The Nguyen group has...synthesized and assembled small molecule-DNA hybrids (SMDHs) as part of programmable atom equivalents . The Rosi group identified design rules for using

Exercise Testing Reveals Everyday Physical Challenges of Bariatric Surgery Candidates.

PubMed

Creel, David B; Schuh, Leslie M; Newton, Robert L; Stote, Joseph J; Cacucci, Brenda M

2017-12-01

Few studies have quantified cardiorespiratory fitness among individuals seeking bariatric surgery. Treadmill testing allows researchers to determine exercise capacity through metabolic equivalents. These findings can assist clinicians in understanding patients' capabilities to carry out various activities of daily living. The purpose of this study was to determine exercise tolerance and the variables associated with fitness, among individuals seeking bariatric surgery. Bariatric surgery candidates completed submaximal treadmill testing and provided ratings of perceived exertion. Each participant also completed questionnaires related to history of exercise, mood, and perceived barriers/benefits of exercise. Over half of participants reported that exercise was "hard to very hard" before reaching 70% of heart rate reserve, and one-third of participants reported that exercise was "moderately hard" at less than 3 metabolic equivalents (light activity). Body mass index and age accounted for the majority of the variance in exercise tolerance, but athletic history, employment status, and perceived health benefits also contributed. Perceived benefit scores were higher than barrier scores. Categories commonly used to describe moderate-intensity exercise (3-6 metabolic equivalents) do not coincide with perceptions of intensity among many bariatric surgery candidates, especially those with a body mass index of 50 or more.

Determination of the elastic and stiffness characteristics of cross-laminated timber plates from flexural wave velocity measurements

NASA Astrophysics Data System (ADS)

Santoni, Andrea; Schoenwald, Stefan; Van Damme, Bart; Fausti, Patrizio

2017-07-01

Cross-laminated timber (CLT) is an engineered wood with good structural properties and it is also economically competitive with the traditional building construction materials. However, due to its low volume density combined with its high stiffness, it does not provide sufficient sound insulation, thus it is necessary to develop specific acoustic treatments in order to increase the noise reduction performance. The material's mechanical properties are required as input data to perform the vibro-acoustic analyses necessary during the design process. In this paper the elastic constants of a CLT plate are derived by fitting the real component of the experimental flexural wave velocity with Mindlin's dispersion relation for thick plates, neglecting the influence of the plate's size and boundary conditions. Furthermore, its apparent elastic and stiffness properties are derived from the same set of experimental data, for the plate considered to be thin. Under this latter assumption the orthotropic behaviour of an equivalent thin CLT plate is described by using an elliptic model and verified with experimental results.

Fatigue-Life Prediction Methodology Using Small-Crack Theory

NASA Technical Reports Server (NTRS)

Newmann, James C., Jr.; Phillips, Edward P.; Swain, M. H.

1997-01-01

This paper reviews the capabilities of a plasticity-induced crack-closure model to predict fatigue lives of metallic materials using 'small-crack theory' for various materials and loading conditions. Crack-tip constraint factors, to account for three-dimensional state-of-stress effects, were selected to correlate large-crack growth rate data as a function of the effective-stress-intensity factor range (delta K(eff)) under constant-amplitude loading. Some modifications to the delta k(eff)-rate relations were needed in the near-threshold regime to fit measured small-crack growth rate behavior and fatigue endurance limits. The model was then used to calculate small- and large-crack growth rates, and to predict total fatigue lives, for notched and un-notched specimens made of two aluminum alloys and a steel under constant-amplitude and spectrum loading. Fatigue lives were calculated using the crack-growth relations and microstructural features like those that initiated cracks for the aluminum alloys and steel for edge-notched specimens. An equivalent-initial-flaw-size concept was used to calculate fatigue lives in other cases. Results from the tests and analyses agreed well.

Detour factors in water and plastic phantoms and their use for range and depth scaling in electron-beam dosimetry.

PubMed

Fernández-Varea, J M; Andreo, P; Tabata, T

1996-07-01

Average penetration depths and detour factors of 1-50 MeV electrons in water and plastic materials have been computed by means of analytical calculation, within the continuous-slowing-down approximation and including multiple scattering, and using the Monte Carlo codes ITS and PENELOPE. Results are compared to detour factors from alternative definitions previously proposed in the literature. Different procedures used in low-energy electron-beam dosimetry to convert ranges and depths measured in plastic phantoms into water-equivalent ranges and depths are analysed. A new simple and accurate scaling method, based on Monte Carlo-derived ratios of average electron penetration depths and thus incorporating the effect of multiple scattering, is presented. Data are given for most plastics used in electron-beam dosimetry together with a fit which extends the method to any other low-Z plastic material. A study of scaled depth-dose curves and mean energies as a function of depth for some plastics of common usage shows that the method improves the consistency and results of other scaling procedures in dosimetry with electron beams at therapeutic energies.

75 FR 44841 - Hazardous Materials: Special Permits and Approvals-Minimum Level of Fitness Determinations...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-29

... Materials: Special Permits and Approvals--Minimum Level of Fitness Determinations; Public Meeting AGENCY... Special Permit and Approval applicant fitness determinations. PHMSA will hold a public meeting on August... minimum level of fitness. DATES: Public Meeting: August 19, 2010; starting at 9:30 a.m. and ending by 3:30...

Using a second‐order differential model to fit data without baselines in protein isothermal chemical denaturation

PubMed Central

Tang, Chuanning; Lew, Scott

2016-01-01

Abstract In vitro protein stability studies are commonly conducted via thermal or chemical denaturation/renaturation of protein. Conventional data analyses on the protein unfolding/(re)folding require well‐defined pre‐ and post‐transition baselines to evaluate Gibbs free‐energy change associated with the protein unfolding/(re)folding. This evaluation becomes problematic when there is insufficient data for determining the pre‐ or post‐transition baselines. In this study, fitting on such partial data obtained in protein chemical denaturation is established by introducing second‐order differential (SOD) analysis to overcome the limitations that the conventional fitting method has. By reducing numbers of the baseline‐related fitting parameters, the SOD analysis can successfully fit incomplete chemical denaturation data sets with high agreement to the conventional evaluation on the equivalent completed data, where the conventional fitting fails in analyzing them. This SOD fitting for the abbreviated isothermal chemical denaturation further fulfills data analysis methods on the insufficient data sets conducted in the two prevalent protein stability studies. PMID:26757366

Application of genetic algorithm in modeling on-wafer inductors for up to 110 Ghz

NASA Astrophysics Data System (ADS)

Liu, Nianhong; Fu, Jun; Liu, Hui; Cui, Wenpu; Liu, Zhihong; Liu, Linlin; Zhou, Wei; Wang, Quan; Guo, Ao

2018-05-01

In this work, the genetic algorithm has been introducted into parameter extraction for on-wafer inductors for up to 110 GHz millimeter-wave operations, and nine independent parameters of the equivalent circuit model are optimized together. With the genetic algorithm, the model with the optimized parameters gives a better fitting accuracy than the preliminary parameters without optimization. Especially, the fitting accuracy of the Q value achieves a significant improvement after the optimization.

The canonical equation of adaptive dynamics for life histories: from fitness-returns to selection gradients and Pontryagin's maximum principle.

PubMed

Metz, Johan A Jacob; Staňková, Kateřina; Johansson, Jacob

2016-03-01

This paper should be read as addendum to Dieckmann et al. (J Theor Biol 241:370-389, 2006) and Parvinen et al. (J Math Biol 67: 509-533, 2013). Our goal is, using little more than high-school calculus, to (1) exhibit the form of the canonical equation of adaptive dynamics for classical life history problems, where the examples in Dieckmann et al. (J Theor Biol 241:370-389, 2006) and Parvinen et al. (J Math Biol 67: 509-533, 2013) are chosen such that they avoid a number of the problems that one gets in this most relevant of applications, (2) derive the fitness gradient occurring in the CE from simple fitness return arguments, (3) show explicitly that setting said fitness gradient equal to zero results in the classical marginal value principle from evolutionary ecology, (4) show that the latter in turn is equivalent to Pontryagin's maximum principle, a well known equivalence that however in the literature is given either ex cathedra or is proven with more advanced tools, (5) connect the classical optimisation arguments of life history theory a little better to real biology (Mendelian populations with separate sexes subject to an environmental feedback loop), (6) make a minor improvement to the form of the CE for the examples in Dieckmann et al. and Parvinen et al.

THE PEAKS AND GEOMETRY OF FITNESS LANDSCAPES

PubMed Central

CRONA, KRISTINA; GREENE, DEVIN; BARLOW, MIRIAM

2012-01-01

Fitness landscapes are central in the theory of adaptation. Recent work compares global and local properties of fitness landscapes. It has been shown that multi-peaked fitness landscapes have a local property called reciprocal sign epistasis interactions. The converse is not true. We show that no condition phrased in terms of reciprocal sign epistasis interactions only, implies multiple peaks. We give a sufficient condition for multiple peaks phrased in terms of two-way interactions. This result is surprising since it has been claimed that no sufficient local condition for multiple peaks exist. We show that our result cannot be generalized to sufficient conditions for three or more peaks. Our proof depends on fitness graphs, where nodes represent genotypes and where arrows point toward more fit genotypes. We also use fitness graphs in order to give a new brief proof of the equivalent characterizations of fitness landscapes lacking genetic constraints on accessible mutational trajectories. We compare a recent geometric classification of fitness landscape based on triangulations of polytopes with qualitative aspects of gene interactions. One observation is that fitness graphs provide information not contained in the geometric classification. We argue that a qualitative perspective may help relating theory of fitness landscapes and empirical observations. PMID:23036916

Environment and Materials Stewardship | NREL

Science.gov Websites

dioxide equivalent of natural gas in heating facilities and experiments; 105metric tons of carbon dioxide equivalent in fleet and equipment; 15 metric tons of carbon dioxide equivalent in fluorinated gases and refrigerants; and 10 metric tons of carbon dioxide equivalent in dry ice use in laboratories. Scope 2 accounts

78 FR 4478 - New Postal Product

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-22

... Equivalent Global Plus 2C Contract Negotiated Service Agreement and Application for Non-Public Treatment of... Equivalent Global Plus 2C Agreements, January 13, 2012. Customers for Global Plus 2C contracts are Postal... application for non-public treatment of material filed under seal. The material filed under seal consists of...

49 CFR 178.507 - Standards for plywood drums.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.507 Standards for plywood drums. (a) The... effectiveness of the drum for the purpose intended. A material other than plywood, of at least equivalent..., lids must be lined with kraft paper or some other equivalent material which must be securely fastened...

77 FR 64450 - Hazardous Materials: Incorporation of Certain Special Permits and Competent Authorities Into...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-22

... varies from the regulations provided an equivalent level of safety is maintained. An approval is a... materials regulations (HMR) provided an equivalent level of safety is maintained. A competent authority (CA... drums. Transportation of spent bleaching earth. Requalification of non-DOT specification cylinders in...

Further Evidence for Increasing Pressure and a Non-spherical Shape in Triton's Atmosphere

NASA Astrophysics Data System (ADS)

Person, M. J.; Elliot, J. L.; McDonald, S. W.; Buie, M. W.; Dunham, E. W.; Millis, R. L.; Nye, R. A.; Olkin, C. B.; Wasserman, L. H.; Young, L. A.; Hubbard, W. B.; Hill, R.; Reitsema, H. J.; Pasachoff, J. M.; Babcock, B. A.; McConnochie, T. M.; Stone, R. C.

2000-10-01

An occultation by Triton of a star denoted as Tr176 by McDonald & Elliot (AJ 109, 1352), was observed on 1997 July 18 from various locations in Australia and North America. After an extensive prediction effort, two complete chords of the occultation were recorded by our PCCD portable data systems. These chords were combined with three others recorded by another group (Sicardy et al., BAAS 30, 1107) to provide an overall geometric solution for Triton's atmosphere at the occultation pressure. A simple circular fit to these five chords yielded a half-light radius of 1439 +/- 10 km, however least squares fitting revealed a significant deviation from the simple circular projection of a spherical atmosphere. The best fitting ellipse (a first order deviation from the circular solution) yielded a mean radius of 1440 +/- 6 km and an ellipticity of 0.040 +/- 0.003. To further characterize the non-spherical solutions to the geometric fits, methods were developed to analyze the data assuming both circular and elliptical profiles. Circular and elliptically focused light curve models corresponding to the best fitting circular and elliptical geometric solutions were fit to the data. Using these light curve fits, the mean pressure at the 1400 km radius (48 km altitude) derived from all the data was 2.23 +/- 0.28 microbar for the circular model and 2.45 +/- 0.32 microbar for the elliptical model. These pressures agree with those for the Tr180 occultation (which occurred a few months later), so these results are consistent with the conclusions of Elliot et al. (Icarus 143, 425) that Triton's surface pressure has increased from 14.0 microbar at the time of the Voyager encounter to 19.0 microbar in 1997. The mean equivalent-isothermal temperature at 1400 km was 43.6 +/- 3.7 K for the circular model and 42.0 +/- 3.6 K for the elliptical model. Within their calculated errors, the equivalent-isothermal temperatures were the same for all Triton latitudes probed.

Applying Rasch analysis to evaluate measurement equivalence of different administration formats of the Activity Limitation scale of the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR).

PubMed

Twiss, J; McKenna, S P; Graham, J; Swetz, K; Sloan, J; Gomberg-Maitland, M

2016-04-09

Electronic formats of patient-reported outcome (PRO) measures are now routinely used in clinical research studies. When changing from a validated paper and pen to electronic administration it is necessary to establish their equivalence. This study reports on the value of Rasch analysis in this process. Three groups of US pulmonary hypertension (PH) patients participated. The first completed an electronic version of the CAMPHOR Activity Limitation scale (e-sample) and this was compared with two pen and paper administrated samples (pp1 and pp2). The three databases were combined and analysed for fit to the Rasch model. Equivalence was evaluated by differential item functioning (DIF) analyses. The three datasets were matched randomly in terms of sample size (n = 147). Mean age (years) and percentage of male respondents were as follows: e-sample (51.7, 16.0 %); pp1 (50.0, 14.0 %); pp2 (55.5, 40.4 %). The combined dataset achieved fit to the Rasch model. Two items showed evidence of borderline DIF. Further analyses showed the inclusion of these items had little impact on Rasch estimates indicating the DIF identified was unimportant. Differences between the performance of the electronic and pen and paper administrations of the CAMPHOR Activity Limitation scale were minor. The results were successful in showing how the Rasch model can be used to determine the equivalence of alternative formats of PRO measures.

Evaluation of marginal and internal fit of ceramic and metallic crown copings using x-ray microtomography (micro-CT) technology.

PubMed

Pimenta, Manuel Antonio; Frasca, Luis Carlos; Lopes, Ricardo; Rivaldo, Elken

2015-08-01

Prosthetic crown fit to the walls of the tooth preparation may vary depending on the material used for crown fabrication. The purpose of this study was to compare the marginal and internal fit of crown copings fabricated from 3 different materials. The selected materials were zirconia (ZirkonZahn system, group Y-TZP), lithium disilicate (IPS e.max Press system, group LSZ), and nickel-chromium alloy (lost-wax casting, group NiCr). Five specimens of each material were seated on standard dies. An x-ray microtomography (micro-CT) device was used to obtain volumetric reconstructions of each specimen. Points for fit measurement were located in Adobe Photoshop, and measurements were obtained in the CTAn SkyScan software environment. Marginal fit was measured at 4 points and internal fit at 9 points in each coping. Mean measurements from the 3 groups were compared by analysis of variance (ANOVA) at the 5% significance level, and between-group differences were assessed with the Tukey range test. The nickel-chromium alloy exhibited the best marginal fit overall, comparable with zirconia and significantly different from lithium disilicate. Lithium disilicate exhibited the lowest mean values for internal fit, similar to zirconia and significantly different from the nickel-chrome alloy. The marginal and internal fit parameters of the 3 tested materials were within clinically acceptable range. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

SU-E-T-353: Verification of Water Equivalent Thickness (WET) and Water Equivalent Spreadness (WES) of Proton Beam

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

Demez, N; Lee, T; Keppel, Cynthia

Purpose: To verify calculated water equivalent thickness (WET) and water equivalent spreadness (WES) in various tissue equivalent media for proton therapy Methods: Water equivalent thicknesses (WET) of tissue equivalent materials have been calculated using the Bragg-Kleeman rule. Lateral spreadness and fluence reduction of proton beams both in those media were calculated using proton loss model (PLM) algorithm. In addition, we calculated lateral spreadness ratios with respect to that in water at the same WET depth and so the WES was defined. The WETs of those media for different proton beam energies were measured using MLIC (Multi-Layered Ionization Chamber). Also, fluencemore » and field sizes in those materials of various thicknesses were measured with ionization chambers and films Results: Calculated WETs are in agreement with measured WETs within 0.5%. We found that water equivalent spreadness (WES) is constant and the fluence and field size measurements verify that fluence can be estimated using the concept of WES. Conclusions: Calculation of WET based on the Bragg-Kleeman rule as well as the constant WES of proton beams for tissue equivalent phantoms can be used to predict fluence and field sizes at the depths of interest both in tissue equivalent media accurately for clinically available protonenergies.« less

Investigation of empirical damping laws for the space shuttle

NASA Technical Reports Server (NTRS)

Bernstein, E. L.

1973-01-01

An analysis of dynamic test data from vibration testing of a number of aerospace vehicles was made to develop an empirical structural damping law. A systematic attempt was made to fit dissipated energy/cycle to combinations of all dynamic variables. The best-fit laws for bending, torsion, and longitudinal motion are given, with error bounds. A discussion and estimate are made of error sources. Programs are developed for predicting equivalent linear structural damping coefficients and finding the response of nonlinearly damped structures.

On the Dust Environment of Comet C/2012 S1 (ISON) from 12 AU Pre-perihelion to the End of its Activity around Perihelion

NASA Astrophysics Data System (ADS)

Moreno, F.; Pozuelos, F.; Aceituno, F.; Casanova, V.; Duffard, R.; López-Moreno, J. J.; Molina, A.; Ortiz, J. L.; Santos-Sanz, P.; Sota, A.; Diepvens, A.; Segundo, A. S.; Bell, C.; Labordena, C.; Bryssinck, E.; Cortés, E.; Reina, E.; García, F.; Gómez, F.; Limón, F.; Soldán, F.; Tifner, F.; Muler, G.; Almendros, I.; Aledo, J.; Bel, J.; Carrillo, J.; Castellano, J.; Curto, J.; Gaitan, J.; Salto, J. L.; Lopesino, J.; Lozano, J.; Hernández, J. F.; González, J. J.; Martín, J. L.; Aymamí, J. M.; Bosch, J. M.; Fernández, J. M.; Vidal, J. R.; Montoro, L.; Tremosa, L.; Campas, M.; Canales, O.; Dekelver, P. J.; Benavides, R.; Naves, R.; Castillo, R.; Climent, T.; Cupillari, T.; Yanamandra-Fisher, P.

2014-08-01

A Monte Carlo dust tail model has been applied to extract the dust environment parameters of the comet C/2012 S1 (ISON) from both Earth-based and SOHO LASCO C3 observations, performed from about six astronomical units (AU) inbound, to just after perihelion passage, when only a small portion of the original comet nucleus has survived in the form of a cloud of tiny particles. The early Afρ and image data are consistent with particle ejection from an extended active area located at latitudes 35°N to 90°N (for a prograde rotating nucleus), with the spin axis having a large obliquity (I ~ 70°). This configuration nicely fits the early images and Afρ data until 3.9 AU inbound, when the emission should become isotropic in order to fit the data. The analysis of LASCO images reveals that, assuming an original nucleus of RN = 500 m with ρ = 1000 kg m-3, at least half of its mass was vaporized when the comet was at about 17 R ⊙ inbound. We conclude that at that time the nucleus suffered a cataclysmic fragmentation releasing a huge amount of material of 2.3 ×1011 kg, equivalent to a sphere of 380 m in radius with density 1000 kg m-3. The surviving material after perihelion passage consists of very small dust particles of 0.1-50 μm in radius with a total mass of just 6.7×108 kg.

Water-equivalent fiber radiation dosimeter with two scintillating materials

PubMed Central

Qin, Zhuang; Hu, Yaosheng; Ma, Yu; Lin, Wei; Luo, Xianping; Zhao, Wenhui; Sun, Weimin; Zhang, Daxin; Chen, Ziyin; Wang, Boran; Lewis, Elfed

2016-01-01

An inorganic scintillating material plastic optical fiber (POF) dosimeter for measuring ionizing radiation during radiotherapy applications is reported. It is necessary that an ideal dosimeter exhibits many desirable qualities, including water equivalence, energy independence, reproducibility, dose linearity. There has been much recent research concerning inorganic dosimeters. However, little reference has been made to date of the depth-dose characteristics of dosimeter materials. In the case of inorganic scintillating materials, they are predominantly non water-equivalent, with their effective atomic weight (Zeff) being typically much greater than that of water. This has been a barrier in preventing inorganic scintillating material dosimeter from being used in actual clinical applications. In this paper, we propose a parallel-paired fiber light guide structure to solve this problem. Two different inorganic scintillating materials are embedded separately in the parallel-paired fiber. It is shown that the information of water depth and absorbed dose at the point of measurement can be extracted by utilizing their different depth-dose properties. PMID:28018715

Toward Worldwide Hepcidin Assay Harmonization: Identification of a Commutable Secondary Reference Material.

PubMed

van der Vorm, Lisa N; Hendriks, Jan C M; Laarakkers, Coby M; Klaver, Siem; Armitage, Andrew E; Bamberg, Alison; Geurts-Moespot, Anneke J; Girelli, Domenico; Herkert, Matthias; Itkonen, Outi; Konrad, Robert J; Tomosugi, Naohisa; Westerman, Mark; Bansal, Sukhvinder S; Campostrini, Natascia; Drakesmith, Hal; Fillet, Marianne; Olbina, Gordana; Pasricha, Sant-Rayn; Pitts, Kelly R; Sloan, John H; Tagliaro, Franco; Weykamp, Cas W; Swinkels, Dorine W

2016-07-01

Absolute plasma hepcidin concentrations measured by various procedures differ substantially, complicating interpretation of results and rendering reference intervals method dependent. We investigated the degree of equivalence achievable by harmonization and the identification of a commutable secondary reference material to accomplish this goal. We applied technical procedures to achieve harmonization developed by the Consortium for Harmonization of Clinical Laboratory Results. Eleven plasma hepcidin measurement procedures (5 mass spectrometry based and 6 immunochemical based) quantified native individual plasma samples (n = 32) and native plasma pools (n = 8) to assess analytical performance and current and achievable equivalence. In addition, 8 types of candidate reference materials (3 concentrations each, n = 24) were assessed for their suitability, most notably in terms of commutability, to serve as secondary reference material. Absolute hepcidin values and reproducibility (intrameasurement procedure CVs 2.9%-8.7%) differed substantially between measurement procedures, but all were linear and correlated well. The current equivalence (intermeasurement procedure CV 28.6%) between the methods was mainly attributable to differences in calibration and could thus be improved by harmonization with a common calibrator. Linear regression analysis and standardized residuals showed that a candidate reference material consisting of native lyophilized plasma with cryolyoprotectant was commutable for all measurement procedures. Mathematically simulated harmonization with this calibrator resulted in a maximum achievable equivalence of 7.7%. The secondary reference material identified in this study has the potential to substantially improve equivalence between hepcidin measurement procedures and contributes to the establishment of a traceability chain that will ultimately allow standardization of hepcidin measurement results. © 2016 American Association for Clinical Chemistry.

Quantification of breast lesion compositions using low-dose spectral mammography: A feasibility study

PubMed Central

Ding, Huanjun; Sennung, David; Cho, Hyo-Min; Molloi, Sabee

2016-01-01

Purpose: The positive predictive power for malignancy can potentially be improved, if the chemical compositions of suspicious breast lesions can be reliably measured in screening mammography. The purpose of this study is to investigate the feasibility of quantifying breast lesion composition, in terms of water and lipid contents, with spectral mammography. Methods: Phantom and tissue samples were imaged with a spectral mammography system based on silicon-strip photon-counting detectors. Dual-energy calibration was performed for material decomposition, using plastic water and adipose-equivalent phantoms as the basis materials. The step wedge calibration phantom consisted of 20 calibration configurations, which ranged from 2 to 8 cm in thickness and from 0% to 100% in plastic water density. A nonlinear rational fitting function was used in dual-energy calibration of the imaging system. Breast lesion phantoms, made from various combinations of plastic water and adipose-equivalent disks, were embedded in a breast mammography phantom with a heterogeneous background pattern. Lesion phantoms with water densities ranging from 0% to 100% were placed at different locations of the heterogeneous background phantom. The water density in the lesion phantoms was measured using dual-energy material decomposition. The thickness and density of the background phantom were varied to test the accuracy of the decomposition technique in different configurations. In addition, an in vitro study was also performed using mixtures of lean and fat bovine tissue of 25%, 50%, and 80% lean weight percentages as the background. Lesions were simulated by using breast lesion phantoms, as well as small bovine tissue samples, composed of carefully weighed lean and fat bovine tissues. The water densities in tissue samples were measured using spectral mammography and compared to measurement using chemical decomposition of the tissue. Results: The thickness of measured and known water contents was compared for various lesion configurations. There was a good linear correlation between the measured and the known values. The root-mean-square errors in water thickness measurements were 0.3 and 0.2 mm for the plastic phantom and bovine tissue backgrounds, respectively. Conclusions: The results indicate that spectral mammography can be used to accurately characterize breast lesion composition in terms of their equivalent water and lipid contents. PMID:27782705

75 FR 42364 - Hazardous Materials: Incorporation of Certain Cargo Tank Special Permits Into Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-21

... ``ROADWAY STRIPING''. (5) Operational controls. A non-DOT specification cargo tank used for roadway striping... package or ship a hazardous material in a manner that varies from the regulations provided an equivalent... least an equivalent level of safety to that specified in the HMR. Implementation of new technologies and...

Toward quantitative estimation of material properties with dynamic mode atomic force microscopy: a comparative study.

PubMed

Ghosal, Sayan; Gannepalli, Anil; Salapaka, Murti

2017-08-11

In this article, we explore methods that enable estimation of material properties with the dynamic mode atomic force microscopy suitable for soft matter investigation. The article presents the viewpoint of casting the system, comprising of a flexure probe interacting with the sample, as an equivalent cantilever system and compares a steady-state analysis based method with a recursive estimation technique for determining the parameters of the equivalent cantilever system in real time. The steady-state analysis of the equivalent cantilever model, which has been implicitly assumed in studies on material property determination, is validated analytically and experimentally. We show that the steady-state based technique yields results that quantitatively agree with the recursive method in the domain of its validity. The steady-state technique is considerably simpler to implement, however, slower compared to the recursive technique. The parameters of the equivalent system are utilized to interpret storage and dissipative properties of the sample. Finally, the article identifies key pitfalls that need to be avoided toward the quantitative estimation of material properties.

Methodological questions of creating tissue-equivalent phantoms

NASA Technical Reports Server (NTRS)

Kolodkin, A. V.; Popov, V. I.; Sychkov, M. A.; Nikl, I.; Erdei, M.; Eyben, O.

1974-01-01

On the basis of analysis and generalization of literature data, the composition of tissue equivalent plastic was justified, parameters of a standard man were determined, plaster and metal forms were created for casting dummies, and an experimental model was produced from tissue equivalent material.

33 CFR 155.120 - Equivalents.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120 Equivalents...

33 CFR 155.120 - Equivalents.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120 Equivalents...

33 CFR 155.120 - Equivalents.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120 Equivalents...

CA II K-line metallicity indicator for field RR Lyrae stars

NASA Astrophysics Data System (ADS)

Clementini, Gisella; Tosi, Monica; Merighi, Roberto

In order to check and, possibly, improve the Preston's Delta S calibration scale, CCD spectra have been obtained for 25 field RR Lyrae variables. Eleven of the program stars have values of (Fe/H) derived by Butler and Deming (1979) from the Fe II lines' strength. For them we find that the equivalent width of the Ca II K line is extremely well correlated to the (Fe/H) values, the best fit relation being: (Fe/H) = 0.43W(K) - 2.75 where W(K) is the equivalent width of the K line. We conclude that the use of the K line equivalent width is at present the best method to derive the (Fe/H) abundance of the RR Lyrae stars.

High energy neutron dosimeter

DOEpatents

Sun, Rai Ko S.F.

1994-01-01

A device for measuring dose equivalents in neutron radiation fields. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning.

X-ray observations of EX Hydrae with the Einstein Solid State Spectrometer

NASA Technical Reports Server (NTRS)

Singh, Jyoti; Swank, Jean

1993-01-01

Einstein SSS X-ray observations of the eclipsing intermediate polar EX Hya are presented. The SSS data have a better resolution at energies extending below 2 keV than do the EXOSAT data. These data reveal the presence of a soft component with a temperature of about 0.74 keV. The phase-resolved data can be fitted to a model of two-temperature thermal plasma with a single absorber, with the result that only the normalization varies with phase. This suggests that part of the soft component might become occulted at minimum. If we assume that the reduction in the flux occurs due to the photoelectric absorption, we find that a high-density material covering only about 40 percent of the emission can fit the data equally well. The EXOSAT and Ginga data of this source favor the accretion curtain model rather than the occultation model. We modify the accretion curtain model by assuming that the modulation is caused by an absorber which partially covers the accreting column at the minimum of the 67-min pulse. An emission line at 1.72 keV is present in the data. The equivalent width of this line varies in phase with the continuum. We associate this line with Si fluorescence.

A general dual-bolus approach for quantitative DCE-MRI.

PubMed

Kershaw, Lucy E; Cheng, Hai-Ling Margaret

2011-02-01

To present a dual-bolus technique for quantitative dynamic contrast-enhanced MRI (DCE-MRI) and show that it can give an arterial input function (AIF) measurement equivalent to that from a single-bolus protocol. Five rabbits were imaged using a dual-bolus technique applicable for high-resolution DCE-MRI, incorporating a time resolved imaging of contrast kinetics (TRICKS) sequence for rapid temporal sampling. AIFs were measured from both the low-dose prebolus and the high-dose main bolus in the abdominal aorta. In one animal, TRICKS and fast spoiled gradient echo (FSPGR) acquisitions were compared. The scaled prebolus AIF was shown to match the main bolus AIF, with 95% confidence intervals overlapping for fits of gamma-variate functions to the first pass and linear fits to the washout phase, with the exception of one case. The AIFs measured using TRICKS and FSPGR were shown to be equivalent in one animal. The proposed technique can capture even the rapid circulation kinetics in the rabbit aorta, and the scaled prebolus AIF is equivalent to the AIF from a high-dose injection. This allows separate measurements of the AIF and tissue uptake curves, meaning that each curve can then be acquired using a protocol tailored to its specific requirements. Copyright © 2011 Elsevier Inc. All rights reserved.

A quality control method for intensity-modulated radiation therapy planning based on generalized equivalent uniform dose.

PubMed

Pang, Haowen; Sun, Xiaoyang; Yang, Bo; Wu, Jingbo

2018-05-01

To ensure good quality intensity-modulated radiation therapy (IMRT) planning, we proposed the use of a quality control method based on generalized equivalent uniform dose (gEUD) that predicts absorbed radiation doses in organs at risk (OAR). We conducted a retrospective analysis of patients who underwent IMRT for the treatment of cervical carcinoma, nasopharyngeal carcinoma (NPC), or non-small cell lung cancer (NSCLC). IMRT plans were randomly divided into data acquisition and data verification groups. OAR in the data acquisition group for cervical carcinoma and NPC were further classified as sub-organs at risk (sOAR). The normalized volume of sOAR and normalized gEUD (a = 1) were analyzed using multiple linear regression to establish a fitting formula. For NSCLC, the normalized intersection volume of the planning target volume (PTV) and lung, the maximum diameter of the PTV (left-right, anterior-posterior, and superior-inferior), and the normalized gEUD (a = 1) were analyzed using multiple linear regression to establish a fitting formula for the lung gEUD (a = 1). The r-squared and P values indicated that the fitting formula was a good fit. In the data verification group, IMRT plans verified the accuracy of the fitting formula, and compared the gEUD (a = 1) for each OAR between the subjective method and the gEUD-based method. In conclusion, the gEUD-based method can be used effectively for quality control and can reduce the influence of subjective factors on IMRT planning optimization. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

A novel method for patient exit and entrance dose prediction based on water equivalent path length measured with an amorphous silicon electronic portal imaging device.

PubMed

Kavuma, Awusi; Glegg, Martin; Metwaly, Mohamed; Currie, Garry; Elliott, Alex

2010-01-21

In vivo dosimetry is one of the quality assurance tools used in radiotherapy to monitor the dose delivered to the patient. Electronic portal imaging device (EPID) images for a set of solid water phantoms of varying thicknesses were acquired and the data fitted onto a quadratic equation, which relates the reduction in photon beam intensity to the attenuation coefficient and material thickness at a reference condition. The quadratic model is used to convert the measured grey scale value into water equivalent path length (EPL) at each pixel for any material imaged by the detector. For any other non-reference conditions, scatter, field size and MU variation effects on the image were corrected by relative measurements using an ionization chamber and an EPID. The 2D EPL is linked to the percentage exit dose table, for different thicknesses and field sizes, thereby converting the plane pixel values at each point into a 2D dose map. The off-axis ratio is corrected using envelope and boundary profiles generated from the treatment planning system (TPS). The method requires field size, monitor unit and source-to-surface distance (SSD) as clinical input parameters to predict the exit dose, which is then used to determine the entrance dose. The measured pixel dose maps were compared with calculated doses from TPS for both entrance and exit depth of phantom. The gamma index at 3% dose difference (DD) and 3 mm distance to agreement (DTA) resulted in an average of 97% passing for the square fields of 5, 10, 15 and 20 cm. The exit dose EPID dose distributions predicted by the algorithm were in better agreement with TPS-calculated doses than phantom entrance dose distributions.

A novel method for patient exit and entrance dose prediction based on water equivalent path length measured with an amorphous silicon electronic portal imaging device

NASA Astrophysics Data System (ADS)

Kavuma, Awusi; Glegg, Martin; Metwaly, Mohamed; Currie, Garry; Elliott, Alex

2010-01-01

In vivo dosimetry is one of the quality assurance tools used in radiotherapy to monitor the dose delivered to the patient. Electronic portal imaging device (EPID) images for a set of solid water phantoms of varying thicknesses were acquired and the data fitted onto a quadratic equation, which relates the reduction in photon beam intensity to the attenuation coefficient and material thickness at a reference condition. The quadratic model is used to convert the measured grey scale value into water equivalent path length (EPL) at each pixel for any material imaged by the detector. For any other non-reference conditions, scatter, field size and MU variation effects on the image were corrected by relative measurements using an ionization chamber and an EPID. The 2D EPL is linked to the percentage exit dose table, for different thicknesses and field sizes, thereby converting the plane pixel values at each point into a 2D dose map. The off-axis ratio is corrected using envelope and boundary profiles generated from the treatment planning system (TPS). The method requires field size, monitor unit and source-to-surface distance (SSD) as clinical input parameters to predict the exit dose, which is then used to determine the entrance dose. The measured pixel dose maps were compared with calculated doses from TPS for both entrance and exit depth of phantom. The gamma index at 3% dose difference (DD) and 3 mm distance to agreement (DTA) resulted in an average of 97% passing for the square fields of 5, 10, 15 and 20 cm. The exit dose EPID dose distributions predicted by the algorithm were in better agreement with TPS-calculated doses than phantom entrance dose distributions.

MO-F-CAMPUS-I-03: Tissue Equivalent Material Phantom to Test and Optimize Coherent Scatter Imaging for Tumor Classification

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

Albanese, K; Morris, R; Lakshmanan, M

Purpose: To accurately model different breast geometries using a tissue equivalent phantom, and to classify these tissues in a coherent x-ray scatter imaging system. Methods: A breast phantom has been designed to assess the capability of coded aperture coherent x-ray scatter imaging system to classify different types of breast tissue (adipose, fibroglandular, tumor). The tissue-equivalent phantom was modeled as a hollow plastic cylinder containing multiple cylindrical and spherical inserts that can be positioned, rearranged, or removed to model different breast geometries. Each enclosure can be filled with a tissue-equivalent material and excised human tumors. In this study, beef and lard,more » placed inside 2-mm diameter plastic Nalgene containers, were used as surrogates for fibroglandular and adipose tissue, respectively. The phantom was imaged at 125 kVp, 40 mA for 10 seconds each with a 1-mm pencil beam. The raw data were reconstructed using a model-based reconstruction algorithm and yielded the location and form factor, or momentum transfer (q) spectrum of the materials that were imaged. The measured material form factors were then compared to the ground truth measurements acquired by x-ray diffraction (XRD) imaging. Results: The tissue equivalent phantom was found to accurately model different types of breast tissue by qualitatively comparing our measured form factors to those of adipose and fibroglandular tissue from literature. Our imaging system has been able to define the location and composition of the various materials in the phantom. Conclusion: This work introduces a new tissue equivalent phantom for testing and optimization of our coherent scatter imaging system for material classification. In future studies, the phantom will enable the use of a variety of materials including excised human tissue specimens in evaluating and optimizing our imaging system using pencil- and fan-beam geometries. United States Department of Homeland Security Duke University Medical Center - Department of Radiology Carl E Ravin Advanced Imaging Laboratories Duke University Medical Physics Graduate Program.« less

Uncertainties in extracted parameters of a Gaussian emission line profile with continuum background.

PubMed

Minin, Serge; Kamalabadi, Farzad

2009-12-20

We derive analytical equations for uncertainties in parameters extracted by nonlinear least-squares fitting of a Gaussian emission function with an unknown continuum background component in the presence of additive white Gaussian noise. The derivation is based on the inversion of the full curvature matrix (equivalent to Fisher information matrix) of the least-squares error, chi(2), in a four-variable fitting parameter space. The derived uncertainty formulas (equivalent to Cramer-Rao error bounds) are found to be in good agreement with the numerically computed uncertainties from a large ensemble of simulated measurements. The derived formulas can be used for estimating minimum achievable errors for a given signal-to-noise ratio and for investigating some aspects of measurement setup trade-offs and optimization. While the intended application is Fabry-Perot spectroscopy for wind and temperature measurements in the upper atmosphere, the derivation is generic and applicable to other spectroscopy problems with a Gaussian line shape.

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

Zhang Yueyang; Deng Licai; Liu Chao

A total of {approx}640, 000 objects from the LAMOST pilot survey have been publicly released. In this work, we present a catalog of DA white dwarfs (DAWDs) from the entire pilot survey. We outline a new algorithm for the selection of white dwarfs (WDs) by fitting Sersic profiles to the Balmer H{beta}, H{gamma}, and H{delta} lines of the spectra, and calculating the equivalent width of the Ca II K line. Two thousand nine hundred sixty-four candidates are selected by constraining the fitting parameters and the equivalent width of the Ca II K line. All the spectra of candidates are visuallymore » inspected. We identify 230 DAWDs (59 of which are already included in the Villanova and SDSS WD catalogs), 20 of which are DAWDs with non-degenerate companions. In addition, 128 candidates are classified as DAWDs/subdwarfs, which means the classifications are ambiguous. The result is consistent with the expected DAWD number estimated based on the LEGUE target selection algorithm.« less

Bacterial growth laws reflect the evolutionary importance of energy efficiency.

PubMed

Maitra, Arijit; Dill, Ken A

2015-01-13

We are interested in the balance of energy and protein synthesis in bacterial growth. How has evolution optimized this balance? We describe an analytical model that leverages extensive literature data on growth laws to infer the underlying fitness landscape and to draw inferences about what evolution has optimized in Escherichia coli. Is E. coli optimized for growth speed, energy efficiency, or some other property? Experimental data show that at its replication speed limit, E. coli produces about four mass equivalents of nonribosomal proteins for every mass equivalent of ribosomes. This ratio can be explained if the cell's fitness function is the the energy efficiency of cells under fast growth conditions, indicating a tradeoff between the high energy costs of ribosomes under fast growth and the high energy costs of turning over nonribosomal proteins under slow growth. This model gives insight into some of the complex nonlinear relationships between energy utilization and ribosomal and nonribosomal production as a function of cell growth conditions.

Factor structure and psychometric properties of the Body Appreciation Scale among adults in Hong Kong.

PubMed

Ng, Siu-Kuen; Barron, David; Swami, Viren

2015-03-01

Previous research has suggested that the factor structure of Body Appreciation Scale (BAS), a widely-used measure of positive body image, may not be cross-culturally equivalent. Here, we used confirmatory factor analysis to evaluate the conceptual equivalence of a Chinese (Cantonese) translation of the BAS among women (n=1319) and men (n=1084) in Hong Kong. Results showed that neither the one-dimensional nor proposed two-dimensional factor structures had adequate fit. Instead, a modified two-dimensional structure, which retained 9 of the 13 BAS items in two factors, had the best fit. However, only one of these factors, reflective of General Body Appreciation, had adequate internal consistency. This factor also had good patterns of construct validity, as indicated through significant correlations with participant body mass index, self-esteem, and (among women) actual-ideal weight discrepancy. The present results suggest that there may be cultural differences in the concept and experience of body appreciation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Crash Testing of Helicopter Airframe Fittings

NASA Technical Reports Server (NTRS)

Clarke, Charles W.; Townsend, William; Boitnott, Richard

2004-01-01

As part of the Rotary Wing Structures Technology Demonstration (RWSTD) program, a surrogate RAH-66 seat attachment fitting was dynamically tested to assess its response to transient, crash impact loads. The dynamic response of this composite material fitting was compared to the performance of an identical fitting subjected to quasi-static loads of similar magnitude. Static and dynamic tests were conducted of both smaller bench level and larger full-scale test articles. At the bench level, the seat fitting was supported in a steel fixture, and in the full-scale tests, the fitting was integrated into a surrogate RAH-66 forward fuselage. Based upon the lessons learned, an improved method to design, analyze, and test similar composite material fittings is proposed.

Heritability of refractive error and ocular biometrics: the Genes in Myopia (GEM) twin study.

PubMed

Dirani, Mohamed; Chamberlain, Matthew; Shekar, Sri N; Islam, Amirul F M; Garoufalis, Pam; Chen, Christine Y; Guymer, Robyn H; Baird, Paul N

2006-11-01

A classic twin study was undertaken to assess the contribution of genes and environment to the development of refractive errors and ocular biometrics in a twin population. A total of 1224 twins (345 monozygotic [MZ] and 267 dizygotic [DZ] twin pairs) aged between 18 and 88 years were examined. All twins completed a questionnaire consisting of a medical history, education, and zygosity. Objective refraction was measured in all twins, and biometric measurements were obtained using partial coherence interferometry. Intrapair correlations for spherical equivalent and ocular biometrics were significantly higher in the MZ than in the DZ twin pairs (P < 0.05), when refraction was considered as a continuous variable. A significant gender difference in the variation of spherical equivalent and ocular biometrics was found (P < 0.05). A genetic model specifying an additive, dominant, and unique environmental factor that was sex limited was the best fit for all measured variables. Heritability of spherical equivalents of 88% and 75% were found in the men and women, respectively, whereas, that of axial length was 94% and 92%, respectively. Additive genetic effects accounted for a greater proportion of the variance in spherical equivalent, whereas the variance in ocular biometrics, particularly axial length was explained mostly by dominant genetic effects. Genetic factors, both additive and dominant, play a significant role in refractive error (myopia and hypermetropia) as well as in ocular biometrics, particularly axial length. The sex limitation ADE model (additive genetic, nonadditive genetic, and environmental components) provided the best-fit genetic model for all parameters.

The Voronoi volume and molecular representation of molar volume: equilibrium simple fluids.

PubMed

Hunjan, Jagtar Singh; Eu, Byung Chan

2010-04-07

The Voronoi volume of simple fluids was previously made use of in connection with volume transport phenomena in nonequilibrium simple fluids. To investigate volume transport phenomena, it is important to develop a method to compute the Voronoi volume of fluids in nonequilibrium. In this work, as a first step to this goal, we investigate the equilibrium limit of the nonequilibrium Voronoi volume together with its attendant related molar (molal) and specific volumes. It is proved that the equilibrium Voronoi volume is equivalent to the molar (molal) volume. The latter, in turn, is proved equivalent to the specific volume. This chain of equivalences provides an alternative procedure of computing the equilibrium Voronoi volume from the molar volume/specific volume. We also show approximate methods of computing the Voronoi and molar volumes from the information on the pair correlation function. These methods may be employed for their quick estimation, but also provide some aspects of the fluid structure and its relation to the Voronoi volume. The Voronoi volume obtained from computer simulations is fitted to a function of temperature and pressure in the region above the triple point but below the critical point. Since the fitting function is given in terms of reduced variables for the Lennard-Jones (LJ) model and the kindred volumes (i.e., specific and molar volumes) are in essence equivalent to the equation of state, the formula obtained is a reduced equation state for simple fluids obeying the LJ model potential in the range of temperature and pressure examined and hence can be used for other simple fluids.

Dimensional structure of DSM-5 posttraumatic stress symptoms in Spanish trauma victims

PubMed Central

Soberón, Carmen; Crespo, María; del Mar Gómez-Gutiérrez, María; Fernández-Lansac, Violeta; Armour, Cherie

2016-01-01

Background Confirmatory factor analytic studies have shown that posttraumatic stress disorder (PTSD) symptoms included in the fifth edition of the Diagnostic and Statistical Manual Disorders (DSM-5) may be better explained by two 6-factor models (the Externalizing Behaviours model and the Anhedonia model) and a 7-factor Hybrid model. The latter model comprises the symptom clusters of intrusion, avoidance, negative affect, anhedonia, externalizing behaviours, and anxious and dysphoric arousal. This model has received empirical support mainly in American samples. Of note, there have been a limited number of studies conducted on samples from other countries. Objective This study aimed to examine the underlying dimensionality of DSM-5 PTSD symptoms in a Spanish clinical sample exposed to a range of traumatic events. Method Participants included 165 adults (78.8% females) seeking treatment in trauma services in the Madrid area (Spain). PTSD was assessed using the Global Assessment of Posttraumatic Stress Scale 5, a Spanish self-report instrument assessing posttraumatic symptoms according to the DSM-5 criteria. Confirmatory factor analyses were conducted in Mplus. Results Both the 7-factor Hybrid model and the 6-factor Anhedonia model demonstrated good and equivalent fit to the data. Conclusions The findings of this study replicate and extend previous research by providing support for both the 7-factor Hybrid model and the 6-factor Anhedonia model in a clinical sample of Spanish trauma survivors. Given equivalent fit for these two models and the fewer number of latent factors in the Anhedonia model, it was selected as optimal in a traumatized Spanish sample. Implications and future research directions are discussed. Highlights of the article The 7-factor Hybrid model (which comprises the intrusion, avoidance, negative affect, anhedonia, externalizing behaviours, and anxious and dysphoric arousal symptoms clusters) and the 6-factor Anhedonia model (in which the externalizing behaviour symptoms are part of the dysphoric arousal symptom cluster) provided equivalent fit to the data. The Anhedonia model is the most parsimonious and thus the optimal-fitting model in the current sample. The findings support the distinctiveness between dysphoric arousal, anxious arousal, negative affect, and anhedonia factors. The separation of the externalizing behaviour symptoms from the dysphoric arousal symptoms does not improve the model fit in the current sample. PMID:27974133

Characterization of low-frequency acoustic wave propagation through a periodic corrugated waveguide

NASA Astrophysics Data System (ADS)

Jiang, Changyong; Huang, Lixi

2018-03-01

In this paper, a periodic corrugated waveguide structure is proposed, and its unit-cell is analyzed by the wave finite element method. In low-frequency range, the unit-cell is treated as an equivalent fluid through a homogenization process, and the equivalent acoustic parameters are obtained, which are validated by finite structure simulations and experiments. The proposed structure is shown to add tortuosity to the waveguide, hence higher equivalent fluid density is achieved, while the system elastic modulus remains unchanged. As a result, the equivalent speed of sound is smaller than normal air. The application of such change of speed of sound is demonstrated in the classic quarter-wavelength resonator based on the corrugated waveguide, which gives a lower resonance frequency with the same side branch length. When the waveguide is filled with porous materials, the added tortuosity enhances the broadband, low-frequency sound absorption by increasing the equivalent mass without bringing in excess damping, the latter being partly responsible for the poor performance of usual porous materials in the low-frequency region. Therefore, the proposed structure provides another dimension for the design and optimization of porous sound absorption materials.

The cardiovascular and metabolic responses to Wii Fit video game playing in middle-aged and older adults.

PubMed

Guderian, B; Borreson, L A; Sletten, L E; Cable, K; Stecker, T P; Probst, M A; Dalleck, L C

2010-12-01

The purpose of this study was (a) to assess the cardiovascular and metabolic responses to Wii Fit video games and (b) to determine if Wii Fit video games meet the American College of Sports Medicine guidelines for improving and maintaining cardiorespiratory fitness. Twenty men and women (mean±SD age, height, and weight: = 58.1±8.8 years, 172.1±10.5 cm, 87.1±22.8 kg, respectively) completed a 20-min Wii Fit testing session consisting of six separate aerobic and balance games. Cardiovascular and metabolic data were collected via a portable calorimetric measurement system. Mean relative exercise intensity was 43.4±16.7% of heart rate reserve. Absolute exercise intensity in metabolic equivalents (METS) was 3.5±0.96. Total net energy expenditure for the Wii Fit video game playing session was 116.2±40.9 kcal/session. Results indicate that playing Wii Fit video games is a feasible alternative to more traditional aerobic exercise modalities for middle-aged and older adults that fulfills the American College of Sports Medicine guidelines for improving and maintaining cardiorespiratory fitness.

Transition from positive to neutral in mutation fixation along with continuing rising fitness in thermal adaptive evolution.

PubMed

Kishimoto, Toshihiko; Iijima, Leo; Tatsumi, Makoto; Ono, Naoaki; Oyake, Ayana; Hashimoto, Tomomi; Matsuo, Moe; Okubo, Masato; Suzuki, Shingo; Mori, Kotaro; Kashiwagi, Akiko; Furusawa, Chikara; Ying, Bei-Wen; Yomo, Tetsuya

2010-10-21

It remains to be determined experimentally whether increasing fitness is related to positive selection, while stationary fitness is related to neutral evolution. Long-term laboratory evolution in Escherichia coli was performed under conditions of thermal stress under defined laboratory conditions. The complete cell growth data showed common continuous fitness recovery to every 2°C or 4°C stepwise temperature upshift, finally resulting in an evolved E. coli strain with an improved upper temperature limit as high as 45.9°C after 523 days of serial transfer, equivalent to 7,560 generations, in minimal medium. Two-phase fitness dynamics, a rapid growth recovery phase followed by a gradual increasing growth phase, was clearly observed at diverse temperatures throughout the entire evolutionary process. Whole-genome sequence analysis revealed the transition from positive to neutral in mutation fixation, accompanied with a considerable escalation of spontaneous substitution rate in the late fitness recovery phase. It suggested that continually increasing fitness not always resulted in the reduction of genetic diversity due to the sequential takeovers by fit mutants, but caused the accumulation of a considerable number of mutations that facilitated the neutral evolution.

SU-E-T-409: Evaluation of Tissue Composition Effect On Dose Distribution in Radiotherapy with 6 MV Photon Beam of a Medical Linac

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

Ghorbani, M; Tabatabaei, Z; Noghreiyan, A Vejdani

Purpose: The aim of this study is to evaluate soft tissue composition effect on dose distribution for various soft tissues and various depths in radiotherapy with 6 MV photon beam of a medical linac. Methods: A phantom and Siemens Primus linear accelerator were simulated using MCNPX Monte Carlo code. In a homogeneous cubic phantom, six types of soft tissue and three types of tissue-equivalent materials were defined separately. The soft tissues were muscle (skeletal), adipose tissue, blood (whole), breast tissue, soft tissue (9-component) and soft tissue (4-component). The tissue-equivalent materials included: water, A-150 tissue-equivalent plastic and perspex. Photon dose relativemore » to dose in 9-component soft tissue at various depths on the beam’s central axis was determined for the 6 MV photon beam. The relative dose was also calculated and compared for various MCNPX tallies including,F8, F6 and,F4. Results: The results of the relative photon dose in various materials relative to dose in 9-component soft tissue and using different tallies are reported in the form of tabulated data. Minor differences between dose distributions in various soft tissues and tissue-equivalent materials were observed. The results from F6 and F4 were practically the same but different with,F8 tally. Conclusion: Based on the calculations performed, the differences in dose distributions in various soft tissues and tissue-equivalent materials are minor but they could be corrected in radiotherapy calculations to upgrade the accuracy of the dosimetric calculations.« less

Sports Nutrition Knowledge, Perceptions, Resources, and Advice Given by Certified CrossFit Trainers

PubMed Central

Maxwell, Cassie; Ruth, Kyle; Friesen, Carol

2017-01-01

Background: CrossFit is a large, growing force in the fitness community. Currently, Level 1 and 2 CrossFit certification classes do not include nutrition education. The purpose of this study was to identify sports nutrition knowledge, perceptions, resources, and advice given by Certified CrossFit Trainers. Methods: An online questionnaire that measured these four constructs was placed on a private Facebook community, open only to certified CrossFit trainers, for 10 days. Results: Complete surveys were obtained from 289 CrossFit trainers. The mean Sport Nutrition Knowledge (SNK) score was 11.1 ± 2.1, equivalent to 65.3% ± 12.4% correct. The trainers perceived nutrition to be extremely important to athletic performance (9.4 ± 0.9 on a 10 point scale). Overall, the trainers graded their SNK higher than that of their CrossFit peers. The internet and CrossFit peers were the most frequently reported sources for nutrition information; Registered Dietitians were the least reported source. The Paleo and Zone diets were the most common dietary regimens recommended by CrossFit trainers. Results indicated a positive correlation between a CrossFit trainer’s self-reported hours of nutrition education and their SNK score (r = 0.17; p < 0.01). Conclusion: Nutrition education modules for Level 1 and 2 CrossFit trainers, developed with input from Board Certified Specialists in Sports Dietetics, are recommended.

State of charge modeling of lithium-ion batteries using dual exponential functions

NASA Astrophysics Data System (ADS)

Kuo, Ting-Jung; Lee, Kung-Yen; Huang, Chien-Kang; Chen, Jau-Horng; Chiu, Wei-Li; Huang, Chih-Fang; Wu, Shuen-De

2016-05-01

A mathematical model is developed by fitting the discharging curve of LiFePO4 batteries and used to investigate the relationship between the state of charge and the closed-circuit voltage. The proposed mathematical model consists of dual exponential terms and a constant term which can fit the characteristics of dual equivalent RC circuits closely, representing a LiFePO4 battery. One exponential term presents the stable discharging behavior and the other one presents the unstable discharging behavior and the constant term presents the cut-off voltage.

High energy neutron dosimeter

DOEpatents

Rai, K.S.F.

1994-01-11

A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures.

Material parameters from frequency dispersion simulation of floating gate memory with Ge nanocrystals in HfO2

NASA Astrophysics Data System (ADS)

Palade, C.; Lepadatu, A. M.; Slav, A.; Lazanu, S.; Teodorescu, V. S.; Stoica, T.; Ciurea, M. L.

2018-01-01

Trilayer memory capacitors with Ge nanocrystals (NCs) floating gate in HfO2 were obtained by magnetron sputtering deposition on p-type Si substrate followed by rapid thermal annealing at relatively low temperature of 600 °C. The frequency dispersion of capacitance and resistance was measured in accumulation regime of Al/HfO2 gate oxide/Ge NCs in HfO2 floating gate/HfO2 tunnel oxide/SiOx/p-Si/Al memory capacitors. For simulation of the frequency dispersion a complex circuit model was used considering an equivalent parallel RC circuit for each layer of the trilayer structure. A series resistance due to metallic contacts and Si substrate was necessary to be included in the model. A very good fit to the experimental data was obtained and the parameters of each layer in the memory capacitor, i.e. capacitances and resistances were determined and in turn the intrinsic material parameters, i.e. dielectric constants and resistivities of layers were evaluated. The results are very important for the study and optimization of the hysteresis behaviour of floating gate memories based on NCs embedded in oxide.

MUSCLE EQUIVALENT MATERIAL

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

Kawashima, K.; Takaku, Y.; Inada, T.

1961-01-01

A tissue-equivalent material was constructed from the following components: polyethylene (CH/sub 2/)/sub n/, 71.4% (by weight), NaNO/sub 3/ 21.3%, Al/sub 2/O/sub 3/ 5.5%, and TiC/sub 2/ 1.8%. The attenuation coefficients of this solid compound, Mix. p in x or gamma rays (40kev --1.25 Mev), were shown to be equal to those of a section of pork loin (m. longissimus dorsi). Thus, Mix. p is concluded to be good phantom material for depth dose measuremeat and suitable material for walls of ionizatlon chambers. (Abstr. Japan Med., 2: No. 3, March 1962)

Equivalent-Continuum Modeling of Nano-Structured Materials

NASA Technical Reports Server (NTRS)

Odegard, Gregory M.; Gates, Thomas S.; Nicholson, Lee M.; Wise, Kristopher E.

2001-01-01

A method has been developed for modeling structure-property relationships of nano-structured materials. This method serves as a link between computational chemistry and solid mechanics by substituting discrete molecular structures with an equivalent-continuum model. It has been shown that this substitution may be accomplished by equating the vibrational potential energy of a nano-structured material with the strain energy of representative truss and continuum models. As an important example with direct application to the development and characterization of single-walled carbon nanotubes, the model has been applied to determine the effective continuum geometry of a graphene sheet. A representative volume element of the equivalent-continuum model has been developed with an effective thickness. This effective thickness has been shown to be similar to, but slightly smaller than, the interatomic spacing of graphite.

Determination of lead equivalent values according to IEC 61331-1:2014—Report and short guidelines for testing laboratories

NASA Astrophysics Data System (ADS)

Büermann, L.

2016-09-01

Materials used for the production of protective devices against diagnostic medical X-radiation described in the international standard IEC 61331-3 need to be specified in terms of their lead attenuation equivalent thickness according to the methods described in IEC 61331-1. In May 2014 the IEC published the second edition of these standards which contain improved methods for the determination of attenuation ratios and the corresponding lead attenuation equivalent thicknesses of lead-reduced or lead-free materials. These methods include the measurement of scattered photons behind the protective material which were hitherto neglected but are becoming more important because of the increasing use of lead-reduced or even lead-free materials. They can offer the same protective effect but are up to 20% lighter and also easier to dispose of. The new method is based on attenuation ratios measured with the so-called ``inverse broad beam condition''. Since the corresponding measurement procedure is new and in some respects more complex than the methods used in the past, it was regarded as being helpful to have a description of how such measurements can reliably be performed. This technical report describes in detail the attenuation ratio measurements and corresponding procedures for the lead equivalent determinations of sample materials using the method with the inverse broad beam condition as carried out at the Physikalisch-Technische Bundesanstalt (PTB). PTB still offers material testing and certification for the German responsible notified body. In addition to the description of the measurements at PTB, a short technical guide is provided for testing laboratories which intend to establish this kind of protective material certification. The guide includes technical recommendations for the testing equipment like X-ray facilities, reference lead sheets and radiation detectors; special procedures for the determination of the lead attenuation equivalent thickness; their uncertainties and the necessary contents of the test certificate.

Accurate Sloshing Modes Modeling: A New Analytical Solution and its Consequences on Control

NASA Astrophysics Data System (ADS)

Gonidou, Luc-Olivier; Desmariaux, Jean

2014-06-01

This study addresses the issue of sloshing modes modeling for GNC analyses purposes. On European launchers, equivalent mechanical systems are commonly used for modeling sloshing effects on launcher dynamics. The representativeness of such a methodology is discussed here. First an exact analytical formulation of the launcher dynamics fitted with sloshing modes is proposed and discrepancies with equivalent mechanical system approach are emphasized. Then preliminary comparative GNC analyses are performed using the different models of dynamics in order to evaluate the impact of the aforementioned discrepancies from GNC standpoint. Special attention is paid to system stability.

Quantitative determination of radio-opacity: equivalence of digital and film X-ray systems.

PubMed

Nomoto, R; Mishima, A; Kobayashi, K; McCabe, J F; Darvell, B W; Watts, D C; Momoi, Y; Hirano, S

2008-01-01

To evaluate the equivalence of a digital X-ray system (DenOptix) to conventional X-ray film in terms of the measured radio-opacity of known filled-resin materials and the suitability of attenuation coefficient for radio-opacity determination. Discs of five thicknesses (0.5-2.5mm) and step-wedges of each of three composite materials of nominal aluminum-equivalence of 50%, 200% and 450% were used. X-ray images of a set of discs (or step-wedge), an aluminum step-wedge, and a lead block were taken at 65 kV and 10 mA at a focus-film distance of 400 mm for 0.15s and 1.6s using an X-ray film or imaging plate. Radio-opacity was determined as equivalent aluminum thickness and attenuation coefficient. The logarithm of the individual optical density or gray scale value, corrected for background, was plotted against thickness, and the attenuation coefficient determined from the slope. The method of ISO 4049 was used for equivalent aluminum thickness. The equivalent aluminum thickness method is not suitable for materials of low radio-opacity, while the attenuation coefficient method could be used for all without difficulty. The digital system gave attenuation coefficients of greater precision than did film, but the use of automatic gain control (AGC) distorted the outcome unusably. Attenuation coefficient is a more precise and generally applicable approach to the determination of radio-opacity. The digital system was equivalent to film but with less noise. The use of AGC is inappropriate for such determinations.

Wing Shape Sensing from Measured Strain

NASA Technical Reports Server (NTRS)

Pak, Chan-Gi

2015-01-01

A new two step theory is investigated for predicting the deflection and slope of an entire structure using strain measurements at discrete locations. In the first step, a measured strain is fitted using a piecewise least squares curve fitting method together with the cubic spline technique. These fitted strains are integrated twice to obtain deflection data along the fibers. In the second step, computed deflection along the fibers are combined with a finite element model of the structure in order to extrapolate the deflection and slope of the entire structure through the use of System Equivalent Reduction and Expansion Process. The theory is first validated on a computational model, a cantilevered rectangular wing. It is then applied to test data from a cantilevered swept wing model.

Analysis and fit of stellar spectra using a mega-database of CMFGEN models

NASA Astrophysics Data System (ADS)

Fierro-Santillán, Celia; Zsargó, Janos; Klapp, Jaime; Díaz-Azuara, Santiago Alfredo; Arrieta, Anabel; Arias, Lorena

2017-11-01

We present a tool for analysis and fit of stellar spectra using a mega database of 15,000 atmosphere models for OB stars. We have developed software tools, which allow us to find the model that best fits to an observed spectrum, comparing equivalent widths and line ratios in the observed spectrum with all models of the database. We use the Hα, Hβ, Hγ, and Hδ lines as criterion of stellar gravity and ratios of He II λ4541/He I λ4471, He II λ4200/(He I+He II λ4026), He II λ4541/He I λ4387, and He II λ4200/He I λ4144 as criterion of T eff.

Dosimetry audit of radiotherapy treatment planning systems.

PubMed

Bulski, Wojciech; Chełmiński, Krzysztof; Rostkowska, Joanna

2015-07-01

In radiotherapy Treatment Planning Systems (TPS) various calculation algorithms are used. The accuracy of dose calculations has to be verified. Numerous phantom types, detectors and measurement methodologies are proposed to verify the TPS calculations with dosimetric measurements. A heterogeneous slab phantom has been designed within a Coordinated Research Project (CRP) of the IAEA. The heterogeneous phantom was developed in the frame of the IAEA CRP. The phantom consists of frame slabs made with polystyrene and exchangeable inhomogeneity slabs equivalent to bone or lung tissue. Special inserts allow to position thermoluminescent dosimeters (TLD) capsules within the polystyrene slabs below the bone or lung equivalent slabs and also within the lung equivalent material. Additionally, there are inserts that allow to position films or ionisation chamber in the phantom. Ten Polish radiotherapy centres (of 30 in total) were audited during on-site visits. Six different TPSs and five calculation algorithms were examined in the presence of inhomogeneities. Generally, most of the results from TLD were within 5 % tolerance. Differences between doses calculated by TPSs and measured with TLD did not exceed 4 % for bone and polystyrene equivalent materials. Under the lung equivalent material, on the beam axis the differences were lower than 5 %, whereas inside the lung equivalent material, off the beam axis, in some cases they were of around 7 %. The TLD results were confirmed with the ionisation chamber measurements. The comparison results of the calculations and the measurements allow to detect limitations of TPS calculation algorithms. The audits performed with the use of heterogeneous phantom and TLD seem to be an effective tool for detecting the limitations in the TPS performance or beam configuration errors at audited radiotherapy departments. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

X-ray phase contrast imaging of the breast: Analysis of tissue simulating materials

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

Vedantham, Srinivasan; Karellas, Andrew

Purpose: Phase contrast imaging, particularly of the breast, is being actively investigated. The purpose of this work is to investigate the x-ray phase contrast properties of breast tissues and commonly used breast tissue substitutes or phantom materials with an aim of determining the phantom materials best representative of breast tissues. Methods: Elemental compositions of breast tissues including adipose, fibroglandular, and skin were used to determine the refractive index, n= 1 -{delta}+i {beta}. The real part of the refractive index, specifically the refractive index decrement ({delta}), over the energy range of 5-50 keV were determined using XOP software (version 2.3, Europeanmore » Synchrotron Radiation Facility, France). Calcium oxalate and calcium hydroxyapatite were considered to represent the material compositions of microcalcifications in vivo. Nineteen tissue substitutes were considered as possible candidates to represent adipose tissue, fibroglandular tissue and skin, and four phantom materials were considered as possible candidates to represent microcalcifications. For each material, either the molecular formula, if available, or the elemental composition based on weight fraction, was used to determine {delta}. At each x-ray photon energy, the absolute percent difference in {delta} between the breast tissue and the substitute material was determined, from which three candidates were selected. From these candidate tissue substitutes, the material that minimized the absolute percent difference in linear attenuation coefficient {mu}, and hence {beta}, was considered to be best representative of that breast tissue. Results: Over the energy range of 5-50 keV, while the {delta} of CB3 and fibroglandular tissue-equivalent material were within 1% of that of fibroglandular tissue, the {mu} of fibroglandular tissue-equivalent material better approximated the fibroglandular tissue. While the {delta} of BR10 and adipose tissue-equivalent material were within 1% of that of adipose tissue, the tissue-equivalent material better approximated the adipose tissue in terms of {mu}. Polymethyl methacrylate, a commonly used tissue substitute, exhibited {delta} greater than fibroglandular tissue by {approx}12%. The A-150 plastic closely approximated the skin. Several materials exhibited {delta} between that of adipose and fibroglandular tissue. However, there was an energy-dependent mismatch in terms of equivalent fibroglandular weight fraction between {delta} and {mu} for these materials. For microcalcifications, aluminum and calcium carbonate were observed to straddle the {delta} and {mu} of calcium oxalate and calcium hydroxyapatite. Aluminum oxide, commonly used to represent microcalcifications in the American College of Radiology recommended phantoms for accreditation exhibited {delta} greater than calcium hydroxyapatite by {approx}23%. Conclusions: A breast phantom comprising A-150 plastic to represent the skin, commercially available adipose and fibroglandular tissue-equivalent formulations to represent adipose and fibroglandular tissue, respectively, was found to be best suited for x-ray phase-sensitive imaging of the breast. Calcium carbonate or aluminum can be used to represent microcalcifications.« less

X-ray phase contrast imaging of the breast: Analysis of tissue simulating materials1

PubMed Central

Vedantham, Srinivasan; Karellas, Andrew

2013-01-01

Purpose: Phase contrast imaging, particularly of the breast, is being actively investigated. The purpose of this work is to investigate the x-ray phase contrast properties of breast tissues and commonly used breast tissue substitutes or phantom materials with an aim of determining the phantom materials best representative of breast tissues. Methods: Elemental compositions of breast tissues including adipose, fibroglandular, and skin were used to determine the refractive index, n = 1 − δ + i β. The real part of the refractive index, specifically the refractive index decrement (δ), over the energy range of 5–50 keV were determined using XOP software (version 2.3, European Synchrotron Radiation Facility, France). Calcium oxalate and calcium hydroxyapatite were considered to represent the material compositions of microcalcifications in vivo. Nineteen tissue substitutes were considered as possible candidates to represent adipose tissue, fibroglandular tissue and skin, and four phantom materials were considered as possible candidates to represent microcalcifications. For each material, either the molecular formula, if available, or the elemental composition based on weight fraction, was used to determine δ. At each x-ray photon energy, the absolute percent difference in δ between the breast tissue and the substitute material was determined, from which three candidates were selected. From these candidate tissue substitutes, the material that minimized the absolute percent difference in linear attenuation coefficient μ, and hence β, was considered to be best representative of that breast tissue. Results: Over the energy range of 5–50 keV, while the δ of CB3 and fibroglandular tissue-equivalent material were within 1% of that of fibroglandular tissue, the μ of fibroglandular tissue-equivalent material better approximated the fibroglandular tissue. While the δ of BR10 and adipose tissue-equivalent material were within 1% of that of adipose tissue, the tissue-equivalent material better approximated the adipose tissue in terms of μ. Polymethyl methacrylate, a commonly used tissue substitute, exhibited δ greater than fibroglandular tissue by ∼12%. The A-150 plastic closely approximated the skin. Several materials exhibited δ between that of adipose and fibroglandular tissue. However, there was an energy-dependent mismatch in terms of equivalent fibroglandular weight fraction between δ and μ for these materials. For microcalcifications, aluminum and calcium carbonate were observed to straddle the δ and μ of calcium oxalate and calcium hydroxyapatite. Aluminum oxide, commonly used to represent microcalcifications in the American College of Radiology recommended phantoms for accreditation exhibited δ greater than calcium hydroxyapatite by ∼23%. Conclusions: A breast phantom comprising A-150 plastic to represent the skin, commercially available adipose and fibroglandular tissue-equivalent formulations to represent adipose and fibroglandular tissue, respectively, was found to be best suited for x-ray phase-sensitive imaging of the breast. Calcium carbonate or aluminum can be used to represent microcalcifications. PMID:23556900

On the dust environment of comet C/2012 S1 (ISON) from 12 AU pre-perihelion to the end of its activity around perihelion

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

Moreno, F.; Pozuelos, F.; Aceituno, F.

2014-08-20

A Monte Carlo dust tail model has been applied to extract the dust environment parameters of the comet C/2012 S1 (ISON) from both Earth-based and SOHO LASCO C3 observations, performed from about six astronomical units (AU) inbound, to just after perihelion passage, when only a small portion of the original comet nucleus has survived in the form of a cloud of tiny particles. The early Afρ and image data are consistent with particle ejection from an extended active area located at latitudes 35°N to 90°N (for a prograde rotating nucleus), with the spin axis having a large obliquity (I ∼more » 70°). This configuration nicely fits the early images and Afρ data until 3.9 AU inbound, when the emission should become isotropic in order to fit the data. The analysis of LASCO images reveals that, assuming an original nucleus of R{sub N} = 500 m with ρ = 1000 kg m{sup –3}, at least half of its mass was vaporized when the comet was at about 17 R {sub ☉} inbound. We conclude that at that time the nucleus suffered a cataclysmic fragmentation releasing a huge amount of material of 2.3 ×10{sup 11} kg, equivalent to a sphere of 380 m in radius with density 1000 kg m{sup –3}. The surviving material after perihelion passage consists of very small dust particles of 0.1-50 μm in radius with a total mass of just 6.7×10{sup 8} kg.« less

SU-F-T-181: Proton Therapy Tissue-Equivalence of 3D Printed Materials

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

Taylor, P; Craft, D; Followill, D

Purpose: This work investigated the proton tissue-equivalence of various 3D printed materials. Methods: Three 3D printers were used to create 5 cm cubic phantoms made of different plastics with varying percentages of infill. White resin, polylactic acid (PLA), and NinjaFlex plastics were used. The infills ranged from 15% to 100%. Each phantom was scanned with a CT scanner to obtain the HU value. The relative linear stopping power (RLSP) was then determined using a multi-layer ion chamber in a 200 MeV proton beam. The RLSP was measured both parallel and perpendicular to the print direction for each material. Results: Themore » HU values of the materials ranged from lung-equivalent (−820 HU σ160) when using a low infill, to soft-tissue-equivalent 159 (σ12). The RLSP of the materials depended on the orientation of the beam relative to the print direction. When the proton beam was parallel to the print direction, the RLSP was generally higher than the RLSP in the perpendicular orientation, by up to 45%. This difference was smaller (less than 6%) for the materials with 100% infill. For low infill cubes irradiated parallel to the print direction, the SOBP curve showed extreme degradation of the beam in the distal region. The materials with 15–25% infill had wide-ranging agreement with a clinical HU-RLSP conversion curve, with some measurements falling within 1% of the curve and others deviating up to 45%. The materials with 100% infill all fell within 7% of the curve. Conclusion: While some materials tested fall within 1% of a clinical HU-RLSP curve, caution should be taken when using 3D printed materials with proton therapy, as the orientation of the beam relative to the print direction can result in a large change in RLSP. Further investigation is needed to measure how the infill pattern affects the material RLSP. This work was supported by PHS grant CA180803.« less

Extraction of Generalized Parton Distributions from combined Deeply Virtual Compton Scattering and Timelike Compton scattering fits

NASA Astrophysics Data System (ADS)

Boer, Marie

2017-09-01

Generalized Parton Distributions (GPDs) contain the correlation between the parton's longitudinal momentum and their transverse distribution. They are accessed through hard exclusive processes, such as Deeply Virtual Compton Scattering (DVCS). DVCS has already been measured in several experiments and several models allow for extracting GPDs from these measurements. Timelike Compton Scattering (TCS) is, at leading order, the time-reversal equivalent process to DVCS and accesses GPDs at the same kinematics. Comparing GPDs extracted from DVCS and TCS is a unique way for proving GPD universality. Combining fits from the two processes will also allow for better constraining the GPDs. We will present our method for extracting GPDs from DVCS and TCS pseudo-data. We will compare fit results from the two processes in similar conditions and present what can be expected in term of contraints on GPDs from combined fits.

An equivalent source model of the satellite-altitude magnetic anomaly field over Australia

NASA Technical Reports Server (NTRS)

Mayhew, M. A.; Johnson, B. D.; Langel, R. A.

1980-01-01

The low-amplitude, long-wavelength magnetic anomaly field measured between 400 and 700 km elevation over Australia by the POGO satellites is modeled by means of the equivalent source technique. Magnetic dipole moments are computed for a latitude-longitude array of dipole sources on the earth's surface such that the dipoles collectively give rise to a field which makes a least squares best fit to that observed. The distribution of magnetic moments is converted to a model of apparent magnetization contrast in a layer of constant (40 km) thickness, which contains information equivalent to the lateral variation in the vertical integral of magnetization down to the Curie isotherm and can be transformed to a model of variable thickness magnetization. It is noted that the closest equivalent source spacing giving a stable solution is about 2.5 deg, corresponding to about half the mean data elevation, and that the magnetization distribution correlates well with some of the principle tectonic elements of Australia.

12 CFR 615.5210 - Risk-adjusted assets.

Code of Federal Regulations, 2010 CFR

2010-01-01

... appropriate credit conversion factor in § 615.5212, is assigned to one of the risk categories specified in... risk-based capital requirement for the credit-enhanced assets, the risk-based capital required under..., determine the appropriate risk weight for any asset or credit equivalent amount that does not fit wholly...

49 CFR 1.44 - Reservation of authority.

Code of Federal Regulations, 2010 CFR

2010-10-01

... relating to safety fitness of an applicant (49 U.S.C. 1653(e)), the making of decisions on requests to... equivalent level: (i) Establishment or abolition of positions; (ii) Hires; (iii) Promotions other than quality and periodic within-grade promotions; (iv) Transfer of personnel to Schedule A, B, or C positions...

Rare B Decays with the BaBar Detector

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

Spanier, Stefane

2001-09-07

The BABAR detector at SLAC's PEP-II storage ring collected a luminosity equivalent data of about 22 fb{sup -1} at the {Upsilon}(4S) resonance during 1999 and 2000. Results on branching fractions of rare and charmless B$-meson decays and first fits for direct CP violation are presented.

Tennis Elbow Diagnosis Using Equivalent Uniform Voltage to Fit the Logistic and the Probit Diseased Probability Models

PubMed Central

Lin, Wei-Chun; Lin, Shu-Yuan; Wu, Li-Fu; Guo, Shih-Sian; Huang, Hsiang-Jui; Chao, Pei-Ju

2015-01-01

To develop the logistic and the probit models to analyse electromyographic (EMG) equivalent uniform voltage- (EUV-) response for the tenderness of tennis elbow. In total, 78 hands from 39 subjects were enrolled. In this study, surface EMG (sEMG) signal is obtained by an innovative device with electrodes over forearm region. The analytical endpoint was defined as Visual Analog Score (VAS) 3+ tenderness of tennis elbow. The logistic and the probit diseased probability (DP) models were established for the VAS score and EMG absolute voltage-time histograms (AVTH). TV50 is the threshold equivalent uniform voltage predicting a 50% risk of disease. Twenty-one out of 78 samples (27%) developed VAS 3+ tenderness of tennis elbow reported by the subject and confirmed by the physician. The fitted DP parameters were TV50 = 153.0 mV (CI: 136.3–169.7 mV), γ 50 = 0.84 (CI: 0.78–0.90) and TV50 = 155.6 mV (CI: 138.9–172.4 mV), m = 0.54 (CI: 0.49–0.59) for logistic and probit models, respectively. When the EUV ≥ 153 mV, the DP of the patient is greater than 50% and vice versa. The logistic and the probit models are valuable tools to predict the DP of VAS 3+ tenderness of tennis elbow. PMID:26380281

Validation of the Brazilian version of the 'Spanish Burnout Inventory' in teachers.

PubMed

Gil-Monte, Pedro R; Carlotto, Mary Sandra; Câmara, Sheila Gonçalves

2010-02-01

To assess factorial validity and internal consistency of the Brazilian version of the 'Spanish Burnout Inventory' (SBI). The translation process of the SBI into Brazilian Portuguese included translation, back translation, and semantic equivalence. A confirmatory factor analysis was carried out using a four-factor model, which was similar to the original SBI. The sample consisted of 714 teachers working in schools in the metropolitan area of the city of Porto Alegre, Southern Brazil, in 2008. The instrument comprises 20 items and four subscales: Enthusiasm towards job (5 items), Psychological exhaustion (4 items), Indolence (6 items), and Guilt (5 items). The model was analyzed using LISREL 8. Goodness-of-Fit statistics showed that the hypothesized model had adequate fit: chi2(164) = 605.86 (p<0.000); Goodness-of-Fit Index = 0.92; Adjusted Goodness-of-Fit Index = 0.90; Root Mean Square Error of Approximation = 0.062; Nonnormed Fit Index = 0.91; Comparative Fit Index = 0.92; and Parsimony Normed Fit Index = 0.77. Cronbach's alpha measures for all subscales were higher than 0.70. The study showed that the SBI has adequate factorial validity and internal consistency to assess burnout in Brazilian teachers.

Influence of Prosthetic Screw Material on Joint Stability in Passive and Non-Passive Implant-Supported Dentures

PubMed Central

Spazzin, Aloísio Oro; Henriques, Guilherme Elias Pessanha; de Arruda Nóbilo, Mauro Antônio; Consani, Rafael Leonardo Xediek; Correr-Sobrinho, Lourenço; Mesquita, Marcelo Ferraz

2009-01-01

Objectives: This study evaluated the influence of prosthetic screw material on joint stability in implantsupported dentures at two levels of fit. Methods: Ten mandibular implant-supported dentures were fabricated. Twenty cast models were fabricated using these dentures. Four groups (n=10) were tested, according to the vertical fit of the dentures [passive and non-passive] and prosthetic screw materials [titanium (Ti) or gold (Au) alloy]. The one-screw test was performed to quantify the vertical misfits using an optic microscope. The loosening torque for the prosthetic screws was measured 24 hours after the tightening torque (10 Ncm) using a digital torque meter. Data were analyzed by two-way ANOVA and Tukey’s test (α=0.05). Results: Overall, dentures with passive fit and Ti screws resulted in significantly higher loosening torque of the prosthetic screws (p<0.05). No significant interaction was found between fit level and screw material (p=0.199). The prosthetic screw material and fit of implant-supported dentures have an influence on screw joint stability. Ti screws presented higher joint stability than Au screws and minimum of misfit should be found clinically to improve the mechanical behavior of the screw joint. PMID:20148135

Equivalent Skin Analysis of Wing Structures Using Neural Networks

NASA Technical Reports Server (NTRS)

Liu, Youhua; Kapania, Rakesh K.

2000-01-01

An efficient method of modeling trapezoidal built-up wing structures is developed by coupling. in an indirect way, an Equivalent Plate Analysis (EPA) with Neural Networks (NN). Being assumed to behave like a Mindlin-plate, the wing is solved using the Ritz method with Legendre polynomials employed as the trial functions. This analysis method can be made more efficient by avoiding most of the computational effort spent on calculating contributions to the stiffness and mass matrices from each spar and rib. This is accomplished by replacing the wing inner-structure with an "equivalent" material that combines to the skin and whose properties are simulated by neural networks. The constitutive matrix, which relates the stress vector to the strain vector, and the density of the equivalent material are obtained by enforcing mass and stiffness matrix equities with rec,ard to the EPA in a least-square sense. Neural networks for the material properties are trained in terms of the design variables of the wing structure. Examples show that the present method, which can be called an Equivalent Skin Analysis (ESA) of the wing structure, is more efficient than the EPA and still fairly good results can be obtained. The present ESA is very promising to be used at the early stages of wing structure design.

Frequency shift of a crystal quartz resonator in thickness-shear modes induced by an array of hemispherical material units.

PubMed

Yuantai Hu; Huiliang Hu; Bin Luo; Huan Xue; Jiemin Xie; Ji Wang

2013-08-01

A two-dimensional model was established to study the dynamic characteristics of a quartz crystal resonator with the upper surface covered by an array of hemispherical material units. A frequency-dependent equivalent mass ratio was proposed to simulate the effect of the covered units on frequency shift of the resonator system. It was found that the equivalent mass ratio alternately becomes positive or negative with change of shear modulus and radius of each material unit, which indicates that the equivalent mass ratio is strongly related to the vibration mode of the covered loadings. The further numerical results show the cyclical feature in the relationship of frequency shift and shear modulus/radius as expected. The solutions are useful in the analysis of frequency stability of quartz resonators and acoustic wave sensors.

42 CFR 82.5 - Definition of terms used in this part.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Illness Compensation Program Act of 2000, 42 U.S.C. 7384-7385 [1994, supp. 2001]. (i) Equivalent dose is... equivalent dose that is received from radiation sources outside of the body. (k) Internal dose means that portion of the equivalent dose that is received from radioactive materials taken into the body. (l) NIOSH...

Wave propagation in equivalent continuums representing truss lattice materials

DOE PAGES

Messner, Mark C.; Barham, Matthew I.; Kumar, Mukul; ...

2015-07-29

Stiffness scales linearly with density in stretch-dominated lattice meta-materials offering the possibility of very light yet very stiff structures. Current additive manufacturing techniques can assemble structures from lattice materials, but the design of such structures will require accurate, efficient simulation methods. Equivalent continuum models have several advantages over discrete truss models of stretch dominated lattices, including computational efficiency and ease of model construction. However, the development an equivalent model suitable for representing the dynamic response of a periodic truss in the small deformation regime is complicated by microinertial effects. This study derives a dynamic equivalent continuum model for periodic trussmore » structures suitable for representing long-wavelength wave propagation and verifies it against the full Bloch wave theory and detailed finite element simulations. The model must incorporate microinertial effects to accurately reproduce long wavelength characteristics of the response such as anisotropic elastic soundspeeds. Finally, the formulation presented here also improves upon previous work by preserving equilibrium at truss joints for simple lattices and by improving numerical stability by eliminating vertices in the effective yield surface.« less

Equivalent Safety Basis for Evaluation of On-Site Packages for US DOE Facilities

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

Smith, A.C.

Packages for transport of radioactive material within the boundaries of a Department of Energy facility (on-site) must conform to the requirements for packages shipped in normal commerce, or must provide equivalent safety. Equivalence is achieved if the frequency of severe on-site accidents, which could result in a release of radioactive material, is less than or equal to the frequency of Beyond-HAC accidents for packages in commerce. This is shown to be achieved it the rate of on-site accident is 22 per 100 MVM or lower. For equivalence to Normal Conditions of Transport, for on-site packages, appropriate, defensible Design Basis Conditionsmore » can be established and the ability of the package to meet the reduced requirements shown in the On-site Safety Assessment.« less

On the Rule of Mixtures for Predicting Stress-Softening and Residual Strain Effects in Biological Tissues and Biocompatible Materials

PubMed Central

Elías-Zúñiga, Alex; Baylón, Karen; Ferrer, Inés; Serenó, Lídia; Garcia-Romeu, Maria Luisa; Bagudanch, Isabel; Grabalosa, Jordi; Pérez-Recio, Tania; Martínez-Romero, Oscar; Ortega-Lara, Wendy; Elizalde, Luis Ernesto

2014-01-01

In this work, we use the rule of mixtures to develop an equivalent material model in which the total strain energy density is split into the isotropic part related to the matrix component and the anisotropic energy contribution related to the fiber effects. For the isotropic energy part, we select the amended non-Gaussian strain energy density model, while the energy fiber effects are added by considering the equivalent anisotropic volumetric fraction contribution, as well as the isotropized representation form of the eight-chain energy model that accounts for the material anisotropic effects. Furthermore, our proposed material model uses a phenomenological non-monotonous softening function that predicts stress softening effects and has an energy term, derived from the pseudo-elasticity theory, that accounts for residual strain deformations. The model’s theoretical predictions are compared with experimental data collected from human vaginal tissues, mice skin, poly(glycolide-co-caprolactone) (PGC25 3-0) and polypropylene suture materials and tracheal and brain human tissues. In all cases examined here, our equivalent material model closely follows stress-softening and residual strain effects exhibited by experimental data. PMID:28788466

On the Rule of Mixtures for Predicting Stress-Softening and Residual Strain Effects in Biological Tissues and Biocompatible Materials.

PubMed

Elías-Zúñiga, Alex; Baylón, Karen; Ferrer, Inés; Serenó, Lídia; García-Romeu, Maria Luisa; Bagudanch, Isabel; Grabalosa, Jordi; Pérez-Recio, Tania; Martínez-Romero, Oscar; Ortega-Lara, Wendy; Elizalde, Luis Ernesto

2014-01-16

In this work, we use the rule of mixtures to develop an equivalent material model in which the total strain energy density is split into the isotropic part related to the matrix component and the anisotropic energy contribution related to the fiber effects. For the isotropic energy part, we select the amended non-Gaussian strain energy density model, while the energy fiber effects are added by considering the equivalent anisotropic volumetric fraction contribution, as well as the isotropized representation form of the eight-chain energy model that accounts for the material anisotropic effects. Furthermore, our proposed material model uses a phenomenological non-monotonous softening function that predicts stress softening effects and has an energy term, derived from the pseudo-elasticity theory, that accounts for residual strain deformations. The model's theoretical predictions are compared with experimental data collected from human vaginal tissues, mice skin, poly(glycolide-co-caprolactone) (PGC25 3-0) and polypropylene suture materials and tracheal and brain human tissues. In all cases examined here, our equivalent material model closely follows stress-softening and residual strain effects exhibited by experimental data.

HDFITS: Porting the FITS data model to HDF5

NASA Astrophysics Data System (ADS)

Price, D. C.; Barsdell, B. R.; Greenhill, L. J.

2015-09-01

The FITS (Flexible Image Transport System) data format has been the de facto data format for astronomy-related data products since its inception in the late 1970s. While the FITS file format is widely supported, it lacks many of the features of more modern data serialization, such as the Hierarchical Data Format (HDF5). The HDF5 file format offers considerable advantages over FITS, such as improved I/O speed and compression, but has yet to gain widespread adoption within astronomy. One of the major holdbacks is that HDF5 is not well supported by data reduction software packages and image viewers. Here, we present a comparison of FITS and HDF5 as a format for storage of astronomy datasets. We show that the underlying data model of FITS can be ported to HDF5 in a straightforward manner, and that by doing so the advantages of the HDF5 file format can be leveraged immediately. In addition, we present a software tool, fits2hdf, for converting between FITS and a new 'HDFITS' format, where data are stored in HDF5 in a FITS-like manner. We show that HDFITS allows faster reading of data (up to 100x of FITS in some use cases), and improved compression (higher compression ratios and higher throughput). Finally, we show that by only changing the import lines in Python-based FITS utilities, HDFITS formatted data can be presented transparently as an in-memory FITS equivalent.

Characterization and validation of the thorax phantom Lungman for dose assessment in chest radiography optimization studies.

PubMed

Rodríguez Pérez, Sunay; Marshall, Nicholas William; Struelens, Lara; Bosmans, Hilde

2018-01-01

This work concerns the validation of the Kyoto-Kagaku thorax anthropomorphic phantom Lungman for use in chest radiography optimization. The equivalence in terms of polymethyl methacrylate (PMMA) was established for the lung and mediastinum regions of the phantom. Patient chest examination data acquired under automatic exposure control were collated over a 2-year period for a standard x-ray room. Parameters surveyed included exposure index, air kerma area product, and exposure time, which were compared with Lungman values. Finally, a voxel model was developed by segmenting computed tomography images of the phantom and implemented in PENELOPE/penEasy Monte Carlo code to compare phantom tissue-equivalent materials with materials from ICRP Publication 89 in terms of organ dose. PMMA equivalence varied depending on tube voltage, from 9.5 to 10.0 cm and from 13.5 to 13.7 cm, for the lungs and mediastinum regions, respectively. For the survey, close agreement was found between the phantom and the patients' median values (deviations lay between 8% and 14%). Differences in lung doses, an important organ for optimization in chest radiography, were below 13% when comparing the use of phantom tissue-equivalent materials versus ICRP materials. The study confirms the value of the Lungman for chest optimization studies.

46 CFR 128.210 - Class II vital systems-materials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.210 Class II vital systems—materials... Commanding Officer, Marine Safety Center, if shown to provide a level of safety equivalent to materials in...

46 CFR 128.210 - Class II vital systems-materials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.210 Class II vital systems—materials... Commanding Officer, Marine Safety Center, if shown to provide a level of safety equivalent to materials in...

46 CFR 128.210 - Class II vital systems-materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.210 Class II vital systems—materials... Commanding Officer, Marine Safety Center, if shown to provide a level of safety equivalent to materials in...

46 CFR 128.210 - Class II vital systems-materials.

Code of Federal Regulations, 2012 CFR

2012-10-01

... ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.210 Class II vital systems—materials... Commanding Officer, Marine Safety Center, if shown to provide a level of safety equivalent to materials in...

46 CFR 128.210 - Class II vital systems-materials.

Code of Federal Regulations, 2014 CFR

2014-10-01

... ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.210 Class II vital systems—materials... Commanding Officer, Marine Safety Center, if shown to provide a level of safety equivalent to materials in...

Editorial Commentary: Polyurethane Meniscal Scaffold: A Perfect Fit or Flop?

PubMed

Barber, F Alan

2018-05-01

The goal of using a synthetic scaffold to establish a biomechanically functioning meniscus or provide an equivalent meniscus substitute is not achieved by the polycaprolactone-polyurethane Actifit scaffold. Recent research, that did not include a control group, shows that the revision rate is significant, and any improvements in patient outcomes could reflect the associated reconstructive surgery. Based on these data and similar published reports, it is premature to conclude that this implant is clinically indicated. The technique is currently more flop than fit. Copyright © 2018 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Evolutionary search for new high-k dielectric materials: methodology and applications to hafnia-based oxides.

PubMed

Zeng, Qingfeng; Oganov, Artem R; Lyakhov, Andriy O; Xie, Congwei; Zhang, Xiaodong; Zhang, Jin; Zhu, Qiang; Wei, Bingqing; Grigorenko, Ilya; Zhang, Litong; Cheng, Laifei

2014-02-01

High-k dielectric materials are important as gate oxides in microelectronics and as potential dielectrics for capacitors. In order to enable computational discovery of novel high-k dielectric materials, we propose a fitness model (energy storage density) that includes the dielectric constant, bandgap, and intrinsic breakdown field. This model, used as a fitness function in conjunction with first-principles calculations and the global optimization evolutionary algorithm USPEX, efficiently leads to practically important results. We found a number of high-fitness structures of SiO2 and HfO2, some of which correspond to known phases and some of which are new. The results allow us to propose characteristics (genes) common to high-fitness structures--these are the coordination polyhedra and their degree of distortion. Our variable-composition searches in the HfO2-SiO2 system uncovered several high-fitness states. This hybrid algorithm opens up a new avenue for discovering novel high-k dielectrics with both fixed and variable compositions, and will speed up the process of materials discovery.

Impact on Bacterial Resistance of Therapeutically Nonequivalent Generics: The Case of Piperacillin-Tazobactam

PubMed Central

Rodriguez, Carlos A.; Agudelo, Maria; Aguilar, Yudy A.; Zuluaga, Andres F.

2016-01-01

Previous studies have demonstrated that pharmaceutical equivalence and pharmacokinetic equivalence of generic antibiotics are necessary but not sufficient conditions to guarantee therapeutic equivalence (better called pharmacodynamic equivalence). In addition, there is scientific evidence suggesting a direct link between pharmacodynamic nonequivalence of generic vancomycin and promotion of resistance in Staphylococcus aureus. To find out if even subtle deviations from the expected pharmacodynamic behavior with respect to the innovator could favor resistance, we studied a generic product of piperacillin-tazobactam characterized by pharmaceutical and pharmacokinetic equivalence but a faulty fit of Hill’s Emax sigmoid model that could be interpreted as pharmacodynamic nonequivalence. We determined the impact in vivo of this generic product on the resistance of a mixed Escherichia coli population composed of ∼99% susceptible cells (ATCC 35218 strain) and a ∼1% isogenic resistant subpopulation that overproduces TEM-1 β-lactamase. After only 24 hours of treatment in the neutropenic murine thigh infection model, the generic amplified the resistant subpopulation up to 20-times compared with the innovator, following an inverted-U dose-response relationship. These findings highlight the critical role of therapeutic nonequivalence of generic antibiotics as a key factor contributing to the global problem of bacterial resistance. PMID:27191163

Modelling and structural analysis of skull/cranial implant: beyond mid-line deformities.

PubMed

Bogu, V Phanindra; Kumar, Y Ravi; Kumar Khanara, Asit

2017-01-01

This computational study explores modelling and finite element study of the implant under Intracranial pressure (ICP) conditions with normal ICP range (7 mm Hg to 15 mm Hg) or increased ICP (>I5 mm Hg). The implant fixation points allow implant behaviour with respect to intracranial pressure conditions. However, increased fixation points lead to variation in deformation and equivalent stress. Finite element analysis is providing a valuable insight to know the deformation and equivalent stress. The patient CT data (Computed Tomography) is processed in Mimics software to get the mesh model. The implant is modelled by using modified reverse engineering technique with the help of Rhinoceros software. This modelling method is applicable for all types of defects including those beyond the middle line and multiple ones. It is designed with eight fixation points and ten fixation points to fix an implant. Consequently, the mechanical deformation and equivalent stress (von Mises) are calculated in ANSYS 15 software with distinctive material properties such as Titanium alloy (Ti6Al4V), Polymethyl methacrylate (PMMA) and polyether-ether-ketone (PEEK). The deformation and equivalent stress results are obtained through ANSYS 15 software. It is observed that Ti6Al4V material shows low deformation and PEEK material shows less equivalent stress. Among all materials PEEK shows noticeably good result. Hence, a concept was established and more clinically relevant results can be expected with implementation of realistic 3D printed model in the future. This will allow physicians to gain knowledge and decrease surgery time with proper planning.

Simultaneous X-ray and Far-Ultraviolet Spectra of AGN with ASCA and HUT

NASA Technical Reports Server (NTRS)

Kriss, Gerard A.

1997-01-01

We obtained ASCA spectra of the Seyfert 1 galaxy NGC 3516 in March 1995. Simultaneous far-UV observations were obtained with the Hopkins Ultraviolet Telescope on the Astro-2 shuttle mission. The ASCA spectrum shows a lightly absorbed power law of energy index 0.78. The low energy absorbing column is significantly less than previously seen. Prominent 0 VII and 0 VIII absorption edges are visible, but, consistent with the much lower total absorbing column, no Fe K absorption edge is detectable. A weak, narrow Fe K(alpha) emission line from cold material is present as well as a broad Fe K(alpha) line. These features are similar to those reported in other Seyfert 1 galaxies. A single warm absorber model provides only an imperfect description of the low energy absorption. In addition to a highly ionized absorber with ionization parameter U = 1.66 and a total column density of 1.4 x 10(exp 22)/sq cm, adding a lower ionization absorber with U = 0.32 and a total column of 6.9 x 10(exp 21)/sq cm significantly improves the fit. The contribution of resonant line scattering to our warm absorber models limits the Doppler parameter to less than 160 km/s at 90% confidence. Turbulence at the sound speed of the photoionized gas provides the best fit. None of the warm absorber models fit to the X-ray spectrum can match the observed equivalent widths of all the UV absorption lines. Accounting for the X-ray and UV absorption simultaneously requires an absorbing region with a broad range of ionization parameters and column densities.

Exaggerated Risk: Prospect Theory and Probability Weighting in Risky Choice

ERIC Educational Resources Information Center

Kusev, Petko; van Schaik, Paul; Ayton, Peter; Dent, John; Chater, Nick

2009-01-01

In 5 experiments, we studied precautionary decisions in which participants decided whether or not to buy insurance with specified cost against an undesirable event with specified probability and cost. We compared the risks taken for precautionary decisions with those taken for equivalent monetary gambles. Fitting these data to Tversky and…

46 CFR 72.40-5 - Where rails required.

Code of Federal Regulations, 2010 CFR

2010-10-01

... business of the vessel, as in the case of a sport fishing vessel, other arrangements may be specifically..., excursion vessels, and vessels of a similar type, the space below the top of the rail shall be fitted with suitable wire mesh or the equivalent. Depending upon the type of construction, the lower rail courses may...

33 CFR 83.07 - Risk of collision (Rule 7).

Code of Federal Regulations, 2011 CFR

2011-07-01

... exists. If there is any doubt such risk shall be deemed to exist. (b) Radar. Proper use shall be made of radar equipment if fitted and operational, including long-range scanning to obtain early warning of risk of collision and radar plotting or equivalent systematic observation of detected objects. (c) Scanty...

33 CFR 83.07 - Risk of collision (Rule 7).

Code of Federal Regulations, 2010 CFR

2010-07-01

... exists. If there is any doubt such risk shall be deemed to exist. (b) Radar. Proper use shall be made of radar equipment if fitted and operational, including long-range scanning to obtain early warning of risk of collision and radar plotting or equivalent systematic observation of detected objects. (c) Scanty...

33 CFR 83.07 - Risk of collision (Rule 7).

Code of Federal Regulations, 2013 CFR

2013-07-01

... exists. If there is any doubt such risk shall be deemed to exist. (b) Radar. Proper use shall be made of radar equipment if fitted and operational, including long-range scanning to obtain early warning of risk of collision and radar plotting or equivalent systematic observation of detected objects. (c) Scanty...

33 CFR 83.07 - Risk of collision (Rule 7).

Code of Federal Regulations, 2014 CFR

2014-07-01

... exists. If there is any doubt such risk shall be deemed to exist. (b) Radar. Proper use shall be made of radar equipment if fitted and operational, including long-range scanning to obtain early warning of risk of collision and radar plotting or equivalent systematic observation of detected objects. (c) Scanty...

33 CFR 83.07 - Risk of collision (Rule 7).

Code of Federal Regulations, 2012 CFR

2012-07-01

... exists. If there is any doubt such risk shall be deemed to exist. (b) Radar. Proper use shall be made of radar equipment if fitted and operational, including long-range scanning to obtain early warning of risk of collision and radar plotting or equivalent systematic observation of detected objects. (c) Scanty...

Construct Equivalence of a National Certification Examination that Uses Dual Languages and Audio Assistance

ERIC Educational Resources Information Center

Wang, Shudong; Wang, Ning; Hoadley, David

2007-01-01

This study used confirmatory factor analysis (CFA) to examine the comparability of the National Nurse Aide Assessment Program (NNAAP[TM]) test scores across language and administration condition groups for calibration and validation samples that were randomly drawn from the same population. Fit statistics supported both the calibration and…

Starch extraction process coupled to protein recovery from leguminous tuberous roots (Pachyrhizus ahipa).

PubMed

Díaz, Andrea; Dini, Cecilia; Viña, Sonia Z; García, María A

2016-11-05

The objective of this work was to fit together the starch extraction from Pachyrhizus ahipa roots and the recovery of the proteins present in these storage organs, making an improved use of this novel raw material. The replacement of water by buffer PO4(-3)/NaCl as solvent in the first extraction steps improved protein extraction without lowering the starch yield. The starches obtained from the traditional and the proposed methods exhibited some differences in appearance and technological and thermal properties, which were endorsed to the adjustment in the methodology of extraction rather than to the use of buffer as solvent. Thus, P. ahipa starch obtaining procedure could be coupled to protein extraction with a minimum change in the methodology. This innovation did not significantly shift the characteristics of the starch obtained and allowed to obtain a protein yield of 135.7mg BSA equivalent protein/100g of fresh roots. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of Flexible Multilayer Circuits and Cables

NASA Technical Reports Server (NTRS)

Barnes, Kevin N.; Bryant, Robert; Holloway, Nancy; Draughon, Fred

2005-01-01

A continuing program addresses the development of flexible multilayer electronic circuits and associated flexible cables. This development is undertaken to help satisfy aerospace-system-engineering requirements for efficient, lightweight electrical and electronic subsystems that can fit within confined spaces, adhere to complexly shaped surfaces, and can be embedded within composite materials. Heretofore, substrate layers for commercial flexible circuitry have been made from sheets of Kapton (or equivalent) polyimide and have been bonded to copper conductors and to other substrate layers by means of adhesives. The substrates for the present developmental flexible circuitry are made from thin films of a polyimide known as LaRC(TM)-SI. This polyimide is thermoplastic and, therefore, offers the potential to eliminate delamination and the need for adhesives. The development work undertaken thus far includes experiments in the use of several techniques of design and fabrication (including computer-aided design and fabrication) of representative flexible circuits. Anticipated future efforts would focus on multilayer bonding, fabrication of prototypes, and overcoming limitations.

Cathode buffer composed of fullerene-ethylenediamine adduct for an organic solar cell

NASA Astrophysics Data System (ADS)

Kimoto, Yoshinori; Akiyama, Tsuyoshi; Fujita, Katsuhiko

2017-02-01

We developed a fullerene-ethylenediamine adduct (C60P-DC) for a cathode buffer material in organic bulk heterojunction solar cells, which enhance the open-circuit voltage (V oc). The evaporative spray deposition using ultra dilute solution (ESDUS) technique was employed to deposit the buffer layer onto the organic active layer to avoid damage during the deposition. By the insertion of a C60P-DC buffer layer, V oc and power conversion efficiency (PCE) were increased from 0.41 to 0.57 V and from 1.65 to 2.10%, respectively. The electron-only device with the C60P-DC buffer showed a much lower current level than that without the buffer, indicating that the V oc increase is caused not by vacuum level shift but by hole blocking. The curve fitting of current density-voltage (J-V) characteristics to the equivalent circuit with a single diode indicated that the decrease in reversed saturation current by hole blocking increased caused the V oc.

Comparison of lead attenuation and lead hardening equivalence of materials used in respect of diagnostic X-ray shielding.

PubMed

Okunade, Akintunde Akangbe

2002-12-01

Present interest is in the shielding of diagnostic X-ray units. Numerical comparison has been made of the attenuation and hardening properties of lead and some particular alternative materials: steel, plate glass and gypsum wallboard. Results show, for particular choices of thickness, that lead and steel can be made to provide closely similar attenuation and spectral hardening, values of lead attenuation equivalent (LAE) and lead hardening equivalent (LHE) thicknesses being nearly the same. Significant differences in the attenuation and hardening properties of lead are found in comparison with plate glass and gypsum wallboard. LAE produces better matching of exposure for lead-plate glass and lead-gypsum wallboard than LHE.

Equivalent circuit for VO{sub 2} phase change material film in reconfigurable frequency selective surfaces

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

Sanphuang, Varittha; Ghalichechian, Nima; Nahar, Niru K.

We developed equivalent circuits of phase change materials based on vanadium dioxide (VO{sub 2}) thin films. These circuits are used to model VO{sub 2} thin films for reconfigurable frequency selective surfaces (FSSs). This is important as it provides a way for designing complex structures. A reconfigurable FSS filter using VO{sub 2} ON/OFF switches is designed demonstrating −60 dB isolation between the states. This filter is used to provide the transmission and reflection responses of the FSS in the frequency range of 0.1–0.6 THz. The comparison between equivalent circuit and full-wave simulation shows excellent agreement.

Evaluation of water-mimicking solid phantom materials for use in HDR and LDR brachytherapy dosimetry

NASA Astrophysics Data System (ADS)

Schoenfeld, Andreas A.; Thieben, Maike; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

2017-12-01

In modern HDR or LDR brachytherapy with photon emitters, fast checks of the dose profiles generated in water or a water-equivalent phantom have to be available in the interest of patient safety. However, the commercially available brachytherapy photon sources cover a wide range of photon emission spectra, and the range of the in-phantom photon spectrum is further widened by Compton scattering, so that the achievement of water-mimicking properties of such phantoms involves high requirements on their atomic composition. In order to classify the degree of water equivalence of the numerous commercially available solid water-mimicking phantom materials and the energy ranges of their applicability, the radial profiles of the absorbed dose to water, D w, have been calculated using Monte Carlo simulations in these materials and in water phantoms of the same dimensions. This study includes the HDR therapy sources Nucletron Flexisource Co-60 HDR (60Co), Eckert und Ziegler BEBIG GmbH CSM-11 (137Cs), Implant Sciences Corporation HDR Yb-169 Source 4140 (169Yb) as well as the LDR therapy sources IsoRay Inc. Proxcelan CS-1 (131Cs), IsoAid Advantage I-125 IAI-125A (125I), and IsoAid Advantage Pd-103 IAPd-103A (103Pd). Thereby our previous comparison between phantom materials and water surrounding a Varian GammaMed Plus HDR therapy 192Ir source (Schoenfeld et al 2015) has been complemented. Simulations were performed in cylindrical phantoms consisting of either water or the materials RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, Plastic Water LR, Original Plastic Water (2015), Plastic Water (1995), Blue Water, polyethylene, polystyrene and PMMA. While for 192Ir, 137Cs and 60Co most phantom materials can be regarded as water equivalent, for 169Yb the materials Plastic Water LR, Plastic Water DT and RW1 appear as water equivalent. For the low-energy sources 106Pd, 131Cs and 125I, only Plastic Water LR can be classified as water equivalent.

Evaluation of water-mimicking solid phantom materials for use in HDR and LDR brachytherapy dosimetry.

PubMed

Schoenfeld, Andreas A; Thieben, Maike; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

2017-11-21

In modern HDR or LDR brachytherapy with photon emitters, fast checks of the dose profiles generated in water or a water-equivalent phantom have to be available in the interest of patient safety. However, the commercially available brachytherapy photon sources cover a wide range of photon emission spectra, and the range of the in-phantom photon spectrum is further widened by Compton scattering, so that the achievement of water-mimicking properties of such phantoms involves high requirements on their atomic composition. In order to classify the degree of water equivalence of the numerous commercially available solid water-mimicking phantom materials and the energy ranges of their applicability, the radial profiles of the absorbed dose to water, D w , have been calculated using Monte Carlo simulations in these materials and in water phantoms of the same dimensions. This study includes the HDR therapy sources Nucletron Flexisource Co-60 HDR ( 60 Co), Eckert und Ziegler BEBIG GmbH CSM-11 ( 137 Cs), Implant Sciences Corporation HDR Yb-169 Source 4140 ( 169 Yb) as well as the LDR therapy sources IsoRay Inc. Proxcelan CS-1 ( 131 Cs), IsoAid Advantage I-125 IAI-125A ( 125 I), and IsoAid Advantage Pd-103 IAPd-103A ( 103 Pd). Thereby our previous comparison between phantom materials and water surrounding a Varian GammaMed Plus HDR therapy 192 Ir source (Schoenfeld et al 2015) has been complemented. Simulations were performed in cylindrical phantoms consisting of either water or the materials RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, Plastic Water LR, Original Plastic Water (2015), Plastic Water (1995), Blue Water, polyethylene, polystyrene and PMMA. While for 192 Ir, 137 Cs and 60 Co most phantom materials can be regarded as water equivalent, for 169 Yb the materials Plastic Water LR, Plastic Water DT and RW1 appear as water equivalent. For the low-energy sources 106 Pd, 131 Cs and 125 I, only Plastic Water LR can be classified as water equivalent.

76 FR 5494 - Pipeline Safety: Mechanical Fitting Failure Reporting Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-01

... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration 49 CFR Part... Safety: Mechanical Fitting Failure Reporting Requirements AGENCY: Pipeline and Hazardous Materials Safety... tightening. A widely accepted industry guidance document, Gas Pipeline Technical Committee (GPTC) Guide, does...

Inventory of Health and Physical Fitness Promotion Materials, Research and Articles from Periodicals of General Interest. Final Report. Report No. 7.

ERIC Educational Resources Information Center

Bozzo, Robert; And Others

This document reports on an effort to identify, collect, and catalog: (1) various fitness- and health-related promotion materials available to the general public by federal, state, and local agencies; and (2) informational items distributed by the private sector. Printed materials are categorized as: (1) currently available brochures and pamphlets…

Fitness Outcomes Related to Glyphosate Resistance in Kochia (Kochia scoparia): What Life History Stage to Examine?

PubMed Central

Osipitan, Omobolanle Adewale; Dille, Johanna Anita

2017-01-01

A fast-spreading weed, kochia (Kochia scoparia), has developed resistance to the widely-used herbicide, glyphosate. Understanding the relationship between the occurrence of glyphosate resistance caused by multiple EPSPS gene copies and kochia fitness may suggest a more effective way of controlling kochia. A study was conducted to assess fitness cost of glyphosate resistance compared to susceptibility in kochia populations at different life history stages, that is rate of seed germination, increase in plant height, days to flowering, biomass accumulation at maturity, and fecundity. Six kochia populations from Scott, Finney, Thomas, Phillips, Wallace, and Wichita counties in western Kansas were characterized for resistance to field-use rate of glyphosate and with an in vivo shikimate accumulation assay. Seed germination was determined in growth chambers at three constant temperatures (5, 10, and 15 C) while vegetative growth and fecundity responses were evaluated in a field study using a target-neighborhood competition design in 2014 and 2015. One target plant from each of the six kochia populations was surrounded by neighboring kochia densities equivalent to 10 (low), 35 (moderate), or 70 (high) kochia plants m−2. In 2015, neighboring corn densities equivalent to 10 and 35 plants m−2 were also evaluated. Treatments were arranged in a randomized complete block design with at least 7 replications. Three kochia populations were classified as glyphosate-resistant (GR) [Scott (SC-R), Finney (FN-R), and Thomas (TH-R)] and three populations were classified as glyphosate-susceptible (GS) [Phillips (PH-S), Wallace (WA-S) and Wichita (WI-S)]. Of the life history stages measured, fitness differences between the GR and GS kochia populations were consistently found in their germination characteristics. The GR kochia showed reduced seed longevity, slower germination rate, and less total germination than the GS kochia. In the field, increases in plant height, biomass accumulation, and fecundity were not clearly different between GR and GS kochia populations (irrespective of neighbor density). Hence, weed management plans should integrate practices that take advantage of the relatively poor germination characteristics of GR kochia. This study suggests that evaluating plant fitness at different life history stages can increase the potential of detecting fitness costs. PMID:28713397

Prevalence of exercise dependence and other behavioral addictions among clients of a Parisian fitness room.

PubMed

Lejoyeux, Michel; Avril, Marine; Richoux, Charlotte; Embouazza, Houcine; Nivoli, Fabrizia

2008-01-01

Exercise dependence is an inadequate pattern of exercise leading to clinically significant negative consequences. Subjects present loss of control of their physical activity, tolerance, and withdrawal symptoms when they do not practice sport. We studied the prevalence of exercise dependence among clients of a Parisian fitness room. We also assessed alcohol and nicotine use disorders, 2 other "socially tolerated" behavioral addictions (compulsive buying and Internet addiction), and 2 disorders related to anxiety focused on the body (bulimia and hypochondria). All clients of the fitness room 18 years and older were invited to participate in the study. Three hundred subjects were included; 125 (42%) presented diagnostic criteria of exercise dependence. Unsurprisingly, exercise dependents spent more hours each day in the fitness center practicing (2.1 vs 1.5 hours per day). They went to the fitness center more often each week (3.5 vs 2.9 days per week). Exercise addicts smoked less; alcohol consumption was equivalent in both groups. Compulsive buying was significantly more frequent in exercise dependents (63% vs 38%), which means they scored higher in the compulsive buying scale (5.4 vs 4.1). Prevalence of hypochondria was equivalent in both groups, but scores in the Whiteley Index of Hypochondria were higher (4.1 vs 3) in the exercise-dependent group. Bulimia was significantly more frequent among exercise dependents (70% vs 47%), who also presented a higher number of bulimic episodes each week (2.5 vs 1.3). Subjects with exercise dependence spent more time on their computer each day (3.9 vs 2.4 hours per day). We found no difference regarding time spent using Internet, the number of e-mails sent or received, and their time at speaking on a cellular phone. Our results lead to systematically study the addictive relation to exercise among regular clients of the fitness rooms. Exercise addicts are exposed to negative consequences for their excess of physical activity. Exercise addiction is also associated to compulsive buying, bulimia, and, in a lesser extent, hypochondria.

Interactions between Soil Habitat and Geographic Range Location Affect Plant Fitness

PubMed Central

Stanton-Geddes, John; Shaw, Ruth G.; Tiffin, Peter

2012-01-01

Populations are often found on different habitats at different geographic locations. This habitat shift may be due to biased dispersal, physiological tolerances or biotic interactions. To explore how fitness of the native plant Chamaecrista fasciculata depends on habitat within, at and beyond its range edge, we planted seeds from five populations in two soil substrates at these geographic locations. We found that with reduced competition, lifetime fitness was always greater or equivalent in one habitat type, loam soils, though early-season survival was greater on sand soils. At the range edge, natural populations are typically found on sand soil habitats, which are also less competitive environments. Early-season survival and fitness differed among source populations, and when transplanted beyond the range edge, range edge populations had greater fitness than interior populations. Our results indicate that even when the optimal soil substrate for a species does not change with geographic range location, the realized niche of a species may be restricted to sub-optimal habitats at the range edge because of the combined effects of differences in abiotic and biotic effects (e.g. competitors) between substrates. PMID:22615745

Determination of tissue equivalent materials of a physical 8-year-old phantom for use in computed tomography

NASA Astrophysics Data System (ADS)

Akhlaghi, Parisa; Miri Hakimabad, Hashem; Rafat Motavalli, Laleh

2015-07-01

This paper reports on the methodology applied to select suitable tissue equivalent materials of an 8-year phantom for use in computed tomography (CT) examinations. To find the appropriate tissue substitutes, first physical properties (physical density, electronic density, effective atomic number, mass attenuation coefficient and CT number) of different materials were studied. Results showed that, the physical properties of water and polyurethane (as soft tissue), B-100 and polyvinyl chloride (PVC) (as bone) and polyurethane foam (as lung) agree more with those of original tissues. Then in the next step, the absorbed doses in the location of 25 thermoluminescent dosimeters (TLDs) as well as dose distribution in one slice of phantom were calculated for original and these proposed materials by Monte Carlo simulation at different tube voltages. The comparisons suggested that at tube voltages of 80 and 100 kVp using B-100 as bone, water as soft tissue and polyurethane foam as lung is suitable for dosimetric study in pediatric CT examinations. In addition, it was concluded that by considering just the mass attenuation coefficient of different materials, the appropriate tissue equivalent substitutes in each desired X-ray energy range could be found.

A discrete spectral analysis for determining quasi-linear viscoelastic properties of biological materials

PubMed Central

Babaei, Behzad; Abramowitch, Steven D.; Elson, Elliot L.; Thomopoulos, Stavros; Genin, Guy M.

2015-01-01

The viscoelastic behaviour of a biological material is central to its functioning and is an indicator of its health. The Fung quasi-linear viscoelastic (QLV) model, a standard tool for characterizing biological materials, provides excellent fits to most stress–relaxation data by imposing a simple form upon a material's temporal relaxation spectrum. However, model identification is challenging because the Fung QLV model's ‘box’-shaped relaxation spectrum, predominant in biomechanics applications, can provide an excellent fit even when it is not a reasonable representation of a material's relaxation spectrum. Here, we present a robust and simple discrete approach for identifying a material's temporal relaxation spectrum from stress–relaxation data in an unbiased way. Our ‘discrete QLV’ (DQLV) approach identifies ranges of time constants over which the Fung QLV model's typical box spectrum provides an accurate representation of a particular material's temporal relaxation spectrum, and is effective at providing a fit to this model. The DQLV spectrum also reveals when other forms or discrete time constants are more suitable than a box spectrum. After validating the approach against idealized and noisy data, we applied the methods to analyse medial collateral ligament stress–relaxation data and identify the strengths and weaknesses of an optimal Fung QLV fit. PMID:26609064

Theoretical and experimental characterization of novel water-equivalent plastics in clinical high-energy carbon-ion beams.

PubMed

Lourenço, A; Wellock, N; Thomas, R; Homer, M; Bouchard, H; Kanai, T; MacDougall, N; Royle, G; Palmans, H

2016-11-07

Water-equivalent plastics are frequently used in dosimetry for experimental simplicity. This work evaluates the water-equivalence of novel water-equivalent plastics specifically designed for light-ion beams, as well as commercially available plastics in a clinical high-energy carbon-ion beam. A plastic- to-water conversion factor [Formula: see text] was established to derive absorbed dose to water in a water phantom from ionization chamber readings performed in a plastic phantom. Three trial plastic materials with varying atomic compositions were produced and experimentally characterized in a high-energy carbon-ion beam. Measurements were performed with a Roos ionization chamber, using a broad un-modulated beam of 11  ×  11 cm 2 , to measure the plastic-to-water conversion factor for the novel materials. The experimental results were compared with Monte Carlo simulations. Commercially available plastics were also simulated for comparison with the plastics tested experimentally, with particular attention to the influence of nuclear interaction cross sections. The measured [Formula: see text] correction increased gradually from 0% at the surface to 0.7% at a depth near the Bragg peak for one of the plastics prepared in this work, while for the other two plastics a maximum correction of 0.8%-1.3% was found. Average differences between experimental and numerical simulations were 0.2%. Monte Carlo results showed that for polyethylene, polystyrene, Rando phantom soft tissue and A-150, the correction increased from 0% to 2.5%-4.0% with depth, while for PMMA it increased to 2%. Water-equivalent plastics such as, Plastic Water, RMI-457, Gammex 457-CTG, WT1 and Virtual Water, gave similar results where maximum corrections were of the order of 2%. Considering the results from Monte Carlo simulations, one of the novel plastics was found to be superior in comparison with the plastic materials currently used in dosimetry, demonstrating that it is feasible to tailor plastic materials to be water-equivalent for carbon ions specifically.

Evolution of haploid-diploid life cycles when haploid and diploid fitnesses are not equal.

PubMed

Scott, Michael F; Rescan, Marie

2017-02-01

Many organisms spend a significant portion of their life cycle as haploids and as diploids (a haploid-diploid life cycle). However, the evolutionary processes that could maintain this sort of life cycle are unclear. Most previous models of ploidy evolution have assumed that the fitness effects of new mutations are equal in haploids and homozygous diploids, however, this equivalency is not supported by empirical data. With different mutational effects, the overall (intrinsic) fitness of a haploid would not be equal to that of a diploid after a series of substitution events. Intrinsic fitness differences between haploids and diploids can also arise directly, for example because diploids tend to have larger cell sizes than haploids. Here, we incorporate intrinsic fitness differences into genetic models for the evolution of time spent in the haploid versus diploid phases, in which ploidy affects whether new mutations are masked. Life-cycle evolution can be affected by intrinsic fitness differences between phases, the masking of mutations, or a combination of both. We find parameter ranges where these two selective forces act and show that the balance between them can favor convergence on a haploid-diploid life cycle, which is not observed in the absence of intrinsic fitness differences. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Aerobic conditioning for team sport athletes.

PubMed

Stone, Nicholas M; Kilding, Andrew E

2009-01-01

Team sport athletes require a high level of aerobic fitness in order to generate and maintain power output during repeated high-intensity efforts and to recover. Research to date suggests that these components can be increased by regularly performing aerobic conditioning. Traditional aerobic conditioning, with minimal changes of direction and no skill component, has been demonstrated to effectively increase aerobic function within a 4- to 10-week period in team sport players. More importantly, traditional aerobic conditioning methods have been shown to increase team sport performance substantially. Many team sports require the upkeep of both aerobic fitness and sport-specific skills during a lengthy competitive season. Classic team sport trainings have been shown to evoke marginal increases/decreases in aerobic fitness. In recent years, aerobic conditioning methods have been designed to allow adequate intensities to be achieved to induce improvements in aerobic fitness whilst incorporating movement-specific and skill-specific tasks, e.g. small-sided games and dribbling circuits. Such 'sport-specific' conditioning methods have been demonstrated to promote increases in aerobic fitness, though careful consideration of player skill levels, current fitness, player numbers, field dimensions, game rules and availability of player encouragement is required. Whilst different conditioning methods appear equivalent in their ability to improve fitness, whether sport-specific conditioning is superior to other methods at improving actual game performance statistics requires further research.

Will Nintendo "Wii Fit" Get You Fit? An Evaluation of the Energy Expenditure from Active-Play Videogames.

PubMed

Xian, Ying; Kakinami, Lisa; Peterson, Eric D; Mustian, Karen M; Fernandez, I Diana

2014-04-01

This study aimed to determine whether Nintendo(®) (Redmond, WA) "Wii Fit™" games can help individuals meet physical activity recommendations. Thirty young healthy volunteers were recruited for this randomized crossover study to evaluate the energy expenditure associated with (1) a 30-minute "Wii Fit Free Run," (2) three 10-minute bouts of "Wii Fit" aerobic games ("Rhythm Boxing," "Super Hula Hoop," and "Advanced Steps"), and (3) 30-minute treadmill running/walking. Energy expenditure was measured by indirect calorimetry using breath-by-breath analyses of O2 consumption and CO2 production. The "Wii Fit" conditions produced a moderate exercise intensity (5.0, 4.1, 3.9, and 3.8 metabolic equivalents [METs] in "Free Run," "Rhythm Boxing," "Super Hula Hoop," and "Advanced Steps"), whereas the treadmill running/walking produced a vigorous exercise intensity (METs=8.0). Based on federal guidelines, an individual could achieve the minimum weekly goal of 500 MET-minutes by playing selected "Wii Fit" aerobics games for 20-26 minutes a day, 5 days a week. Although not as vigorous as the treadmill, active-play videogames such as "Wii Fit" may provide an alternative way to encourage exercise and increase adoption and adherence to the physical activity guidelines.

A new formula for normal tissue complication probability (NTCP) as a function of equivalent uniform dose (EUD).

PubMed

Luxton, Gary; Keall, Paul J; King, Christopher R

2008-01-07

To facilitate the use of biological outcome modeling for treatment planning, an exponential function is introduced as a simpler equivalent to the Lyman formula for calculating normal tissue complication probability (NTCP). The single parameter of the exponential function is chosen to reproduce the Lyman calculation to within approximately 0.3%, and thus enable easy conversion of data contained in empirical fits of Lyman parameters for organs at risk (OARs). Organ parameters for the new formula are given in terms of Lyman model m and TD(50), and conversely m and TD(50) are expressed in terms of the parameters of the new equation. The role of the Lyman volume-effect parameter n is unchanged from its role in the Lyman model. For a non-homogeneously irradiated OAR, an equation relates d(ref), n, v(eff) and the Niemierko equivalent uniform dose (EUD), where d(ref) and v(eff) are the reference dose and effective fractional volume of the Kutcher-Burman reduction algorithm (i.e. the LKB model). It follows in the LKB model that uniform EUD irradiation of an OAR results in the same NTCP as the original non-homogeneous distribution. The NTCP equation is therefore represented as a function of EUD. The inverse equation expresses EUD as a function of NTCP and is used to generate a table of EUD versus normal tissue complication probability for the Emami-Burman parameter fits as well as for OAR parameter sets from more recent data.

Cross-cultural measurements of psychological well-being: the psychometric equivalence of Cantonese, Vietnamese, and Laotian translations of the Affect Balance Scale.

PubMed Central

Devins, G M; Beiser, M; Dion, R; Pelletier, L G; Edwards, R G

1997-01-01

OBJECTIVES: This paper evaluates the cultural equivalence of Cantonese, Vietnamese, and Laotian translations of the Affect Balance Scale. METHODS: The scale was completed by 399 Vietnamese, 193 Laotian, 756 Cantonese, and 319 English speakers who were participants in the Clarke Institute-University of Toronto Refugee Resettlement Project (n = 1667). RESULTS: Confirmatory factor analyses indicated a good fit between the hypothesized two-factor model (separate factors for positive and negative affect) across the original English-language version and each of the Asian-language translations. Factorial invariance (numbers and patterns of factor loadings) was evident across all versions of the scale. No evidence of item bias was detected by mixed Language x Item analyses of variance. Acceptable reliability was observed; coefficient alphas ranged from .62 to .72 for positive affect and from .62 to .70 for negative affect items. CONCLUSIONS: These findings substantiate the cultural equivalence of the three translations of the scale for population health research. Important future research directions made possible by the availability of culturally equivalent instruments are discussed. PMID:9184508

Spectral K-edge subtraction imaging

NASA Astrophysics Data System (ADS)

Zhu, Y.; Samadi, N.; Martinson, M.; Bassey, B.; Wei, Z.; Belev, G.; Chapman, D.

2014-05-01

We describe a spectral x-ray transmission method to provide images of independent material components of an object using a synchrotron x-ray source. The imaging system and process is similar to K-edge subtraction (KES) imaging where two imaging energies are prepared above and below the K-absorption edge of a contrast element and a quantifiable image of the contrast element and a water equivalent image are obtained. The spectral method, termed ‘spectral-KES’ employs a continuous spectrum encompassing an absorption edge of an element within the object. The spectrum is prepared by a bent Laue monochromator with good focal and energy dispersive properties. The monochromator focuses the spectral beam at the object location, which then diverges onto an area detector such that one dimension in the detector is an energy axis. A least-squares method is used to interpret the transmitted spectral data with fits to either measured and/or calculated absorption of the contrast and matrix material-water. The spectral-KES system is very simple to implement and is comprised of a bent Laue monochromator, a stage for sample manipulation for projection and computed tomography imaging, and a pixelated area detector. The imaging system and examples of its applications to biological imaging are presented. The system is particularly well suited for a synchrotron bend magnet beamline with white beam access.

76 FR 593 - New Postal Product

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-05

... 1-2. \\1\\ Notice of United States Postal Service of Filing a Functionally Equivalent Global Expedited Package Services 3 Negotiated Service Agreement and Application for Non-Public Treatment of Materials... Filing a Functionally Equivalent Global Expedited Package Services 3 Negotiated Service Agreement and...

78 FR 79710 - New Postal Product

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-31

... Functionally Equivalent Global Expedited Package Services 3 Negotiated Service Agreement and Application for Non-Public Treatment of Materials Filed Under Seal, December 23, 2013 (Notice). II. Background The.... CP2010-71 to serve as the baseline agreement for comparison of potentially functionally equivalent...

76 FR 80412 - New Postal Product

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-23

... Service of Filing Functionally Equivalent Inbound Competitive Multi-Service Agreement with a Foreign... application for non-public treatment of certain materials. The Postal Service also provided a redacted copy of... that the Postal Service proposed adding other functionally equivalent agreements as price categories...

50 CFR 679.24 - Gear limitations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... material that is brightly colored, UV-protected plastic tubing or 3/8 inch polyester line or material of an... tubing or 3/8 inch polyester line or material of an equivalent density. (iv) Snap gear streamer standard...

Press-fit versus threaded acetabular cups in total hip arthroplasty: Functional and radiological results after five years.

PubMed

Ellenrieder, Martin; Bader, Rainer; Bergschmidt, Philipp; Mittelmeier, Wolfram

2016-03-01

Prospectively the outcome after total hip replacement with a new threaded acetabular cup design was compared to an established press-fit cup. After 1, 2 and 5 years, the 36-item Short Form Health Survey, Western Ontario and McMaster University Osteoarthritis Index and Harris Hip Score revealed no significant differences between the two groups (each group: n=42 patients), except for a higher Harris Hip Score in the threaded cup group after five years (p=0.02). After five years, one threaded cup had a mild radiolucent line without further signs of loosening. All other cups of both groups (98.6%) showed a full osseous integration. The cup inclination angle ranged from 41-58° (threaded cups) to 39-77° (press-fit cups). The new threaded cup provides equivalent clinical outcomes and osseous integration but more precise implant positioning compared to the press-fit design. No complications typically ascribed to threaded cups (acetabular fractures, bone resorption, nerve impairment) occurred.

Biodegradation of Dense Non-Aqueous Phase Liquids (DNAPL) Through Bioaugmentation of Source Areas - Dover National Test Site, Dover, Delaware

DTIC Science & Technology

2008-08-01

the distribution of DNAPL. The OSU research team evaluated the use of radon as a partitioning groundwater tracer. The DNAPL release fulfilled one...close to the source area generated more PCE equivalent mass over time. The exponential decay from the fitted line (predicted PCE, orange line in each

46 CFR 105.35-15 - Fire hose.

Code of Federal Regulations, 2010 CFR

2010-10-01

... bronze or equivalent metal. (e) All fittings on fire hose shall be of brass, copper, or other suitable corrosion resistant metal. (f) A length of fire hose shall be attached to each fire hydrant at all times... 46 Shipping 4 2010-10-01 2010-10-01 false Fire hose. 105.35-15 Section 105.35-15 Shipping COAST...

The Local Minima Problem in Hierarchical Classes Analysis: An Evaluation of a Simulated Annealing Algorithm and Various Multistart Procedures

ERIC Educational Resources Information Center

Ceulemans, Eva; Van Mechelen, Iven; Leenen, Iwin

2007-01-01

Hierarchical classes models are quasi-order retaining Boolean decomposition models for N-way N-mode binary data. To fit these models to data, rationally started alternating least squares (or, equivalently, alternating least absolute deviations) algorithms have been proposed. Extensive simulation studies showed that these algorithms succeed quite…

Frequency response measurements in battery electrodes

NASA Technical Reports Server (NTRS)

Thomas, Daniel L.

1992-01-01

Electrical impedance spectroscopy was used to investigate the behavior of porous zinc, silver, cadmium, and nickel electrodes. State of charge could be correlated with impedance data for all but the nickel electrodes. State of health was correlated with impedance data for two AgZn cells, one apparently good and the other bad. The impedance data was fit to equivalent circuit models.

The Construct Validity of the Self Description Questionnaire on High School Students in Kenya

ERIC Educational Resources Information Center

Mucherah, Winnie; Finch, Holmes

2010-01-01

This study investigated the structural equivalence of the Self Description Questionnaire (SDQ) in relation to Kenyan high school students. A total of 1,990 students from two same-sex boarding schools participated. Confirmatory factor analysis revealed the overall model fit the data well. However, an examination of the individual factors revealed…

Assessing Fit of Item Response Models Using the Information Matrix Test

ERIC Educational Resources Information Center

Ranger, Jochen; Kuhn, Jorg-Tobias

2012-01-01

The information matrix can equivalently be determined via the expectation of the Hessian matrix or the expectation of the outer product of the score vector. The identity of these two matrices, however, is only valid in case of a correctly specified model. Therefore, differences between the two versions of the observed information matrix indicate…

Fitting Prony Series To Data On Viscoelastic Materials

NASA Technical Reports Server (NTRS)

Hill, S. A.

1995-01-01

Improved method of fitting Prony series to data on viscoelastic materials involves use of least-squares optimization techniques. Based on optimization techniques yields closer correlation with data than traditional method. Involves no assumptions regarding the gamma'(sub i)s and higher-order terms, and provides for as many Prony terms as needed to represent higher-order subtleties in data. Curve-fitting problem treated as design-optimization problem and solved by use of partially-constrained-optimization techniques.

Metastable coexistence of multiple genotypes in a constant environment with a single resource through fixed settings of a multiplication-survival trade-off.

PubMed

Maharjan, Ram; Ferenci, Thomas

2016-04-01

The biological complexity of trade-offs has been a major obstacle in understanding bacterial diversity and coexistence. Here we reduce the biological complexity by using isogenic Escherichia coli strains differing only in a multiplication-survival trade-off regulated by RpoS. The contribution of trade-off characteristics to fitness in different environments was determined. We then designed an environment with intermediate-stress levels that elicits an equivalent fitness. We found metastable coexistence of three strains in steady-state chemostats until mutations changed the relative fitness of competing strains. Our results help explain the rich intra- and inter-species diversity of bacteria through alternative settings of relatively few trade-offs. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

USING A RISK-BASED METHODOLOGY FOR THE TRANSFER OF RADIOACTIVE MATERIAL WITHIN THE SAVANNAH RIVER SITE BOUNDARY

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

Loftin, B; Watkins, R; Loibl, M

2010-06-03

Shipment of radioactive materials (RAM) is discussed in the Code of Federal Regulations in parts of both 49 CFR and 10 CFR. The regulations provide the requirements and rules necessary for the safe shipment of RAM across public highways, railways, waterways, and through the air. These shipments are sometimes referred to as in-commerce shipments. Shipments of RAM entirely within the boundaries of Department of Energy sites, such as the Savannah River Site (SRS), can be made using methodology allowing provisions to maintain equivalent safety while deviating from the regulations for in-commerce shipments. These onsite shipments are known as transfers atmore » the SRS. These transfers must follow the requirements approved in a site-specific Transportation Safety Document (TSD). The TSD defines how the site will transfer materials so that they have equivalence to the regulations. These equivalences are documented in an Onsite Safety Assessment (OSA). The OSA can show how a particular packaging used onsite is equivalent to that which would be used for an in-commerce shipment. This is known as a deterministic approach. However, when a deterministic approach is not viable, the TSD allows for a risk-based OSA to be written. These risk-based assessments show that if a packaging does not provide the necessary safety to ensure that materials are not released (during normal or accident conditions) then the worst-case release of materials does not result in a dose consequence worse than that defined for the SRS. This paper will discuss recent challenges and successes using this methodology at the SRS.« less

Equivalent-Continuum Modeling With Application to Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Odegard, Gregory M.; Gates, Thomas S.; Nicholson, Lee M.; Wise, Kristopher E.

2002-01-01

A method has been proposed for developing structure-property relationships of nano-structured materials. This method serves as a link between computational chemistry and solid mechanics by substituting discrete molecular structures with equivalent-continuum models. It has been shown that this substitution may be accomplished by equating the vibrational potential energy of a nano-structured material with the strain energy of representative truss and continuum models. As important examples with direct application to the development and characterization of single-walled carbon nanotubes and the design of nanotube-based devices, the modeling technique has been applied to determine the effective-continuum geometry and bending rigidity of a graphene sheet. A representative volume element of the chemical structure of graphene has been substituted with equivalent-truss and equivalent continuum models. As a result, an effective thickness of the continuum model has been determined. This effective thickness has been shown to be significantly larger than the interatomic spacing of graphite. The effective thickness has been shown to be significantly larger than the inter-planar spacing of graphite. The effective bending rigidity of the equivalent-continuum model of a graphene sheet was determined by equating the vibrational potential energy of the molecular model of a graphene sheet subjected to cylindrical bending with the strain energy of an equivalent continuum plate subjected to cylindrical bending.

78 FR 70601 - International Mail Contract

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-26

... Notice of Filing Functionally Equivalent Agreement, November 15, 2013 (collectively, Notice). II. The... Service filed an application for non-public treatment of materials filed under seal (Attachment 1); a... agreement to one previously found to be functionally equivalent to the Inbound Market-Dominant Multi-Service...

Stochastic Analysis and Design of Heterogeneous Microstructural Materials System

NASA Astrophysics Data System (ADS)

Xu, Hongyi

Advanced materials system refers to new materials that are comprised of multiple traditional constituents but complex microstructure morphologies, which lead to superior properties over the conventional materials. To accelerate the development of new advanced materials system, the objective of this dissertation is to develop a computational design framework and the associated techniques for design automation of microstructure materials systems, with an emphasis on addressing the uncertainties associated with the heterogeneity of microstructural materials. Five key research tasks are identified: design representation, design evaluation, design synthesis, material informatics and uncertainty quantification. Design representation of microstructure includes statistical characterization and stochastic reconstruction. This dissertation develops a new descriptor-based methodology, which characterizes 2D microstructures using descriptors of composition, dispersion and geometry. Statistics of 3D descriptors are predicted based on 2D information to enable 2D-to-3D reconstruction. An efficient sequential reconstruction algorithm is developed to reconstruct statistically equivalent random 3D digital microstructures. In design evaluation, a stochastic decomposition and reassembly strategy is developed to deal with the high computational costs and uncertainties induced by material heterogeneity. The properties of Representative Volume Elements (RVE) are predicted by stochastically reassembling SVE elements with stochastic properties into a coarse representation of the RVE. In design synthesis, a new descriptor-based design framework is developed, which integrates computational methods of microstructure characterization and reconstruction, sensitivity analysis, Design of Experiments (DOE), metamodeling and optimization the enable parametric optimization of the microstructure for achieving the desired material properties. Material informatics is studied to efficiently reduce the dimension of microstructure design space. This dissertation develops a machine learning-based methodology to identify the key microstructure descriptors that highly impact properties of interest. In uncertainty quantification, a comparative study on data-driven random process models is conducted to provide guidance for choosing the most accurate model in statistical uncertainty quantification. Two new goodness-of-fit metrics are developed to provide quantitative measurements of random process models' accuracy. The benefits of the proposed methods are demonstrated by the example of designing the microstructure of polymer nanocomposites. This dissertation provides material-generic, intelligent modeling/design methodologies and techniques to accelerate the process of analyzing and designing new microstructural materials system.

46 CFR 160.056-3 - Fittings and equipment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 6 2011-10-01 2011-10-01 false Fittings and equipment. 160.056-3 Section 160.056-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Rescue Boat § 160.056-3 Fittings and equipment. (a) Fittings. (1...

Dosimetric verification of the anisotropic analytical algorithm in lung equivalent heterogeneities with and without bone equivalent heterogeneities

PubMed Central

Ono, Kaoru; Endo, Satoru; Tanaka, Kenichi; Hoshi, Masaharu; Hirokawa, Yutaka

2010-01-01

Purpose: In this study, the authors evaluated the accuracy of dose calculations performed by the convolution∕superposition based anisotropic analytical algorithm (AAA) in lung equivalent heterogeneities with and without bone equivalent heterogeneities. Methods: Calculations of PDDs using the AAA and Monte Carlo simulations (MCNP4C) were compared to ionization chamber measurements with a heterogeneous phantom consisting of lung equivalent and bone equivalent materials. Both 6 and 10 MV photon beams of 4×4 and 10×10 cm2 field sizes were used for the simulations. Furthermore, changes of energy spectrum with depth for the heterogeneous phantom using MCNP were calculated. Results: The ionization chamber measurements and MCNP calculations in a lung equivalent phantom were in good agreement, having an average deviation of only 0.64±0.45%. For both 6 and 10 MV beams, the average deviation was less than 2% for the 4×4 and 10×10 cm2 fields in the water-lung equivalent phantom and the 4×4 cm2 field in the water-lung-bone equivalent phantom. Maximum deviations for the 10×10 cm2 field in the lung equivalent phantom before and after the bone slab were 5.0% and 4.1%, respectively. The Monte Carlo simulation demonstrated an increase of the low-energy photon component in these regions, more for the 10×10 cm2 field compared to the 4×4 cm2 field. Conclusions: The low-energy photon by Monte Carlo simulation component increases sharply in larger fields when there is a significant presence of bone equivalent heterogeneities. This leads to great changes in the build-up and build-down at the interfaces of different density materials. The AAA calculation modeling of the effect is not deemed to be sufficiently accurate. PMID:20879604

46 CFR 108.105 - Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations, and tests. 108.105 Section 108.105 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT General § 108...

46 CFR 108.105 - Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations, and tests. 108.105 Section 108.105 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT General § 108...

46 CFR 108.105 - Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations, and tests. 108.105 Section 108.105 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT General § 108...

Long-Term Effects of Changes in Cardiorespiratory Fitness and Body Mass Index on All-Cause and Cardiovascular Disease Mortality in Men: The Aerobics Center Longitudinal Study

PubMed Central

Lee, Duck-chul; Sui, Xuemei; Artero, Enrique G.; Lee, I-Min; Church, Timothy S.; McAuley, Paul A.; Stanford, Fatima C.; Kohl, Harold W.; Blair, Steven N.

2011-01-01

Background The combined associations of changes in cardiorespiratory fitness and body mass index (BMI) with mortality remain controversial and uncertain. Methods and Results We examined the independent and combined associations of changes in fitness and BMI with all-cause and cardiovascular disease (CVD) mortality in 14 345 men (mean age 44 years) with at least two medical examinations. Fitness, in metabolic equivalents (METs), was estimated from a maximal treadmill test. BMI was calculated using measured weight and height. Changes in fitness and BMI between the baseline and last examinations over 6.3 years were classified into loss, stable, or gain groups. During 11.4 years of follow-up after the last examination, 914 all-cause and 300 CVD deaths occurred. The hazard ratios (95% confidence intervals) of all-cause and CVD mortality were 0.70 (0.59 to 0.83) and 0.73 (0.54 to 0.98) for stable fitness, and 0.61 (0.51 to 0.73) and 0.58 (0.42 to 0.80) for fitness gain, respectively, compared with fitness loss in multivariable analyses including BMI change. Every 1-MET improvement was associated with 15% and 19% lower risk of all-cause and CVD mortality, respectively. BMI change was not associated with all-cause or CVD mortality after adjusting for possible confounders and fitness change. In the combined analyses, men who lost fitness had higher all-cause and CVD mortality risks regardless of BMI change. Conclusions Maintaining or improving fitness is associated with a lower risk of all-cause and CVD mortality in men. Preventing age-associated fitness loss is important for longevity regardless of BMI change. PMID:22144631

Comparison of the x-ray attenuation properties of breast calcifications, aluminium, hydroxyapatite and calcium oxalate.

PubMed

Warren, L M; Mackenzie, A; Dance, D R; Young, K C

2013-04-07

Aluminium is often used as a substitute material for calcifications in phantom measurements in mammography. Additionally, calcium oxalate, hydroxyapatite and aluminium are used in simulation studies. This assumes that these materials have similar attenuation properties to calcification, and this assumption is examined in this work. Sliced mastectomy samples containing calcification were imaged at ×5 magnification using a digital specimen cabinet. Images of the individual calcifications were extracted, and the diameter and contrast of each calculated. The thicknesses of aluminium required to achieve the same contrast as each calcification when imaged under the same conditions were calculated using measurements of the contrast of aluminium foils. As hydroxyapatite and calcium oxalate are also used to simulate calcifications, the equivalent aluminium thicknesses of these materials were also calculated using tabulated attenuation coefficients. On average the equivalent aluminium thickness was 0.85 times the calcification diameter. For calcium oxalate and hydroxyapatite, the equivalent aluminium thicknesses were 1.01 and 2.19 times the thickness of these materials respectively. Aluminium and calcium oxalate are suitable substitute materials for calcifications. Hydroxyapatite is much more attenuating than the calcifications and aluminium. Using solid hydroxyapatite as a substitute for calcification of the same size would lead to excessive contrast in the mammographic image.

Cardiorespiratory Fitness and Incidence of Type 2 Diabetes in United States Veterans on Statin Therapy.

PubMed

Kokkinos, Peter; Faselis, Charles; Narayan, Puneet; Myers, Jonathan; Nylen, Eric; Sui, Xuemei; Zhang, Jiajia; Lavie, Carl J

2017-10-01

Impact of cardiorespiratory fitness on statin-related incidence of type 2 diabetes has not been assessed. We assessed the cardiorespiratory fitness and diabetes incidence association in dyslipidemic patients on statins. We identified dyslipidemic patients with a normal exercise test performed during 1986 and 2014 at the Veterans Affairs Medical Centers in Washington, DC or Palo Alto, Calif. The statin-treated patients (n = 4092; age = 58.8 ± 10.9 years) consisted of 2701 Blacks and 1391 Whites. None had evidence of type 2 diabetes prior to statin therapy. We formed 4 fitness categories based on age and peak metabolic equivalents achieved: Least-fit (n = 954), Low-fit (n = 1201), Moderate-fit (n = 1242), and High-fit (n = 695). The non-statin-treated cohort (n = 3001; age = 57.2 ± 11.2 years) with no evidence of type 2 diabetes prior to the exercise test served as controls. Diabetes incidence was 24% higher in statin-treated compared with non-statin-treated patients (P <.001). In the statin-treated cohort, 1075 (26.3%) developed diabetes (average annual incidence rate of 30.6 events/1000 person-years). Compared with the Least-fit, adjusted risk decreased progressively with increasing fitness and was 34% lower for High-fit patients (hazard ratio [HR] 0.66; 95% confidence interval [CI], 0.53-0.82; P <.001). Compared with the nonstatin cohort, elevated risk was evident only in the Least-fit (HR 1.50; 95% CI, 1.30-1.73; P <.001) and Low-fit patients (HR 1.22; 95% CI, 1.06-1.41; P = .006). Risk of diabetes in statin-treated dyslipidemic patients was inversely and independently associated with cardiorespiratory fitness. The increased risk was evident only in relatively low-fitness patients. Improving fitness may modulate the potential diabetogenic effects of statins. Published by Elsevier Inc.

Thermodynamic parameters of bonds in glassy materials from viscosity-temperature relationships.

PubMed

Ojovan, Michael I; Travis, Karl P; Hand, Russell J

2007-10-17

Doremus's model of viscosity assumes that viscous flow in amorphous materials is mediated by broken bonds (configurons). The resulting equation contains four coefficients, which are directly related to the entropies and enthalpies of formation and motion of the configurons. Thus by fitting this viscosity equation to experimental viscosity data these enthalpy and entropy terms can be obtained. The non-linear nature of the equation obtained means that the fitting process is non-trivial. A genetic algorithm based approach has been developed to fit the equation to experimental viscosity data for a number of glassy materials, including SiO 2 , GeO 2 , B 2 O 3 , anorthite, diopside, xNa 2 O-(1-x)SiO 2 , xPbO-(1-x)SiO 2 , soda-lime-silica glasses, salol, and α-phenyl-o-cresol. Excellent fits of the equation to the viscosity data were obtained over the entire temperature range. The fitting parameters were used to quantitatively determine the enthalpies and entropies of formation and motion of configurons in the analysed systems and the activation energies for flow at high and low temperatures as well as fragility ratios using the Doremus criterion for fragility. A direct anti-correlation between fragility ratio and configuron percolation threshold, which determines the glass transition temperature in the analysed materials, was found.

Theoretical comparison, equivalent transformation, and conjunction operations of electromagnetic induction generator and triboelectric nanogenerator for harvesting mechanical energy.

PubMed

Zhang, Chi; Tang, Wei; Han, Changbao; Fan, Fengru; Wang, Zhong Lin

2014-06-11

Triboelectric nanogenerator (TENG) is a newly invented technology that is effective using conventional organic materials with functionalized surfaces for converting mechanical energy into electricity, which is light weight, cost-effective and easy scalable. Here, we present the first systematic analysis and comparison of EMIG and TENG from their working mechanisms, governing equations and output characteristics, aiming at establishing complementary applications of the two technologies for harvesting various mechanical energies. The equivalent transformation and conjunction operations of the two power sources for the external circuit are also explored, which provide appropriate evidences that the TENG can be considered as a current source with a large internal resistance, while the EMIG is equivalent to a voltage source with a small internal resistance. The theoretical comparison and experimental validations presented in this paper establish the basis of using the TENG as a new energy technology that could be parallel or possibly equivalently important as the EMIG for general power application at large-scale. It opens a field of organic nanogenerator for chemists and materials scientists who can be first time using conventional organic materials for converting mechanical energy into electricity at a high efficiency. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Update to core reporting practices in structural equation modeling.

PubMed

Schreiber, James B

This paper is a technical update to "Core Reporting Practices in Structural Equation Modeling." 1 As such, the content covered in this paper includes, sample size, missing data, specification and identification of models, estimation method choices, fit and residual concerns, nested, alternative, and equivalent models, and unique issues within the SEM family of techniques. Copyright © 2016 Elsevier Inc. All rights reserved.

If the School Fits...Adult Education from the Student's Perspective. [Videotape].

ERIC Educational Resources Information Center

Capitol Region Education Council, Hartford, CT.

In this 23-minute videotape, a panel of 13 women and men of various racial and ethic backgrounds who are enrolled in a high school equivalency program in Bloomfield, Connecticut, share their thoughts about participation in adult education. In the first part of the tape, the panel members explain why they decided to return to school (desire to make…

Comparing Fit and Reliability Estimates of a Psychological Instrument Using Second-Order CFA, Bifactor, and Essentially Tau-Equivalent (Coefficient Alpha) Models via AMOS 22

ERIC Educational Resources Information Center

Black, Ryan A.; Yang, Yanyun; Beitra, Danette; McCaffrey, Stacey

2015-01-01

Estimation of composite reliability within a hierarchical modeling framework has recently become of particular interest given the growing recognition that the underlying assumptions of coefficient alpha are often untenable. Unfortunately, coefficient alpha remains the prominent estimate of reliability when estimating total scores from a scale with…

The research of Raman spectra measurement system based on tiled-grating monochromator

NASA Astrophysics Data System (ADS)

Liu, Li-na; Zhang, Yin-chao; Chen, Si-ying; Chen, He; Guo, Pan; Wang, Yuan

2013-09-01

A set of Raman spectrum measurement system, essentially a Raman spectrometer, has been independently designed and accomplished by our research group. This system adopts tiled-grating structure, namely two 50mm × 50mm holographic gratings are tiled to form a big spectral grating. It not only improves the resolution but also reduces the cost. This article outlines the Raman spectroscopy system's composition structure and performance parameters. Then corresponding resolutions of the instrument under different criterions are deduced through experiments and data fitting. The result shows that the system's minimum resolution is up to 0.02nm, equivalent to 0.5cm-1 wavenumber under Rayleigh criterion; and it will be up to 0.007nm, equivalent to 0.19cm-1 wavenumber under Sparrow criterion. Then Raman spectra of CCl4 and alcohol have been obtained by the spectrometer, which agreed with the standard spectrum respectively very well. Finally, we measured the spectra of the alcohol solutions with different concentrations and extracted the intensity of characteristic peaks from smoothed spectra. Linear fitting between intensity of characteristic peaks and alcohol solution concentrations has been made. And the linear correlation coefficient is 0.96.

Estimation of Handling Qualities Parameters of the Tu-144 Supersonic Transport Aircraft from Flight Test Data

NASA Technical Reports Server (NTRS)

Curry, Timothy J.; Batterson, James G. (Technical Monitor)

2000-01-01

Low order equivalent system (LOES) models for the Tu-144 supersonic transport aircraft were identified from flight test data. The mathematical models were given in terms of transfer functions with a time delay by the military standard MIL-STD-1797A, "Flying Qualities of Piloted Aircraft," and the handling qualities were predicted from the estimated transfer function coefficients. The coefficients and the time delay in the transfer functions were estimated using a nonlinear equation error formulation in the frequency domain. Flight test data from pitch, roll, and yaw frequency sweeps at various flight conditions were used for parameter estimation. Flight test results are presented in terms of the estimated parameter values, their standard errors, and output fits in the time domain. Data from doublet maneuvers at the same flight conditions were used to assess the predictive capabilities of the identified models. The identified transfer function models fit the measured data well and demonstrated good prediction capabilities. The Tu-144 was predicted to be between level 2 and 3 for all longitudinal maneuvers and level I for all lateral maneuvers. High estimates of the equivalent time delay in the transfer function model caused the poor longitudinal rating.

Process for magnetic beneficiating petroleum cracking catalyst

DOEpatents

Doctor, R.D.

1993-10-05

A process is described for beneficiating a particulate zeolite petroleum cracking catalyst having metal values in excess of 1000 ppm nickel equivalents. The particulate catalyst is passed through a magnetic field in the range of from about 2 Tesla to about 5 Tesla generated by a superconducting quadrupole open-gradient magnetic system for a time sufficient to effect separation of said catalyst into a plurality of zones having different nickel equivalent concentrations. A first zone has nickel equivalents of about 6,000 ppm and greater, a second zone has nickel equivalents in the range of from about 2000 ppm to about 6000 ppm, and a third zone has nickel equivalents of about 2000 ppm and less. The zones of catalyst are separated and the second zone material is recycled to a fluidized bed of zeolite petroleum cracking catalyst. The low nickel equivalent zone is treated while the high nickel equivalent zone is discarded. 1 figures.

Process for magnetic beneficiating petroleum cracking catalyst

DOEpatents

Doctor, Richard D.

1993-01-01

A process for beneficiating a particulate zeolite petroleum cracking catalyst having metal values in excess of 1000 ppm nickel equivalents. The particulate catalyst is passed through a magnetic field in the range of from about 2 Tesla to about 5 Tesla generated by a superconducting quadrupole open-gradient magnetic system for a time sufficient to effect separation of said catalyst into a plurality of zones having different nickel equivalent concentrations. A first zone has nickel equivalents of about 6,000 ppm and greater, a second zone has nickel equivalents in the range of from about 2000 ppm to about 6000 ppm, and a third zone has nickel equivalents of about 2000 ppm and less. The zones of catalyst are separated and the second zone material is recycled to a fluidized bed of zeolite petroleum cracking catalyst. The low nickel equivalent zone is treated while the high nickel equivalent zone is discarded.

LOGISTIC FUNCTION PROFILE FIT: A least-squares program for fitting interface profiles to an extended logistic function

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

Kirchhoff, William H.

2012-09-15

The extended logistic function provides a physically reasonable description of interfaces such as depth profiles or line scans of surface topological or compositional features. It describes these interfaces with the minimum number of parameters, namely, position, width, and asymmetry. Logistic Function Profile Fit (LFPF) is a robust, least-squares fitting program in which the nonlinear extended logistic function is linearized by a Taylor series expansion (equivalent to a Newton-Raphson approach) with no apparent introduction of bias in the analysis. The program provides reliable confidence limits for the parameters when systematic errors are minimal and provides a display of the residuals frommore » the fit for the detection of systematic errors. The program will aid researchers in applying ASTM E1636-10, 'Standard practice for analytically describing sputter-depth-profile and linescan-profile data by an extended logistic function,' and may also prove useful in applying ISO 18516: 2006, 'Surface chemical analysis-Auger electron spectroscopy and x-ray photoelectron spectroscopy-determination of lateral resolution.' Examples are given of LFPF fits to a secondary ion mass spectrometry depth profile, an Auger surface line scan, and synthetic data generated to exhibit known systematic errors for examining the significance of such errors to the extrapolation of partial profiles.« less

[Keratoconus special soft contact lens fitting].

PubMed

Yamazaki, Ester Sakae; da Silva, Vanessa Cristina Batista; Morimitsu, Vagner; Sobrinho, Marcelo; Fukushima, Nelson; Lipener, César

2006-01-01

To evaluate the fitting and use of a soft contact lens in keratoconic patients. Retrospective study on 80 eyes of 66 patients, fitted with a special soft contact lens for keratoconus, at the Contact Lens Section of UNIFESP and private clinics. Keratoconus was classified according to degrees of disease severity by keratometric pattern. Age, gender, diagnosis, keratometry, visual acuity, spherical equivalent (SE), base curve and clinical indication were recorded. Of 66 patients (80 eyes) with keratoconus the mean age was 29 years, 51.5% were men and 48.5% women. According to the groups: 15.0% were incipient, 53.7% moderate, 26.3% advanced and 5.0% were severe. The majority of the eyes of patients using contact lenses (91.25%) achieved visual acuity better than 20/40. To 88 eyes 58% were tihed with lens with spherical power (mean -5.45 diopters) and 41% with spherocylinder power (from -0.5 to -5.00 cylindrical diopters). The most frequent base curve was 7.6 in 61% of the eyes. The main reasons for this special lens fitting were due to reduced tolerance and poor fitting pattern achieved with other lenses. The special soft contact lens is useful in fitting difficult keratoconic patients by offering comfort and improving visual rehabilitation that may allow more patients to postpone the need for corneal transplant.

Why "suboptimal" is optimal: Jensen's inequality and ectotherm thermal preferences.

PubMed

Martin, Tara Laine; Huey, Raymond B

2008-03-01

Body temperature (T(b)) profoundly affects the fitness of ectotherms. Many ectotherms use behavior to control T(b) within narrow levels. These temperatures are assumed to be optimal and therefore to match body temperatures (Trmax) that maximize fitness (r). We develop an optimality model and find that optimal body temperature (T(o)) should not be centered at Trmax but shifted to a lower temperature. This finding seems paradoxical but results from two considerations relating to Jensen's inequality, which deals with how variance and skew influence integrals of nonlinear functions. First, ectotherms are not perfect thermoregulators and so experience a range of T(b). Second, temperature-fitness curves are asymmetric, such that a T(b) higher than Trmax depresses fitness more than will a T(b) displaced an equivalent amount below Trmax. Our model makes several predictions. The magnitude of the optimal shift (Trmax - To) should increase with the degree of asymmetry of temperature-fitness curves and with T(b) variance. Deviations should be relatively large for thermal specialists but insensitive to whether fitness increases with Trmax ("hotter is better"). Asymmetric (left-skewed) T(b) distributions reduce the magnitude of the optimal shift but do not eliminate it. Comparative data (insects, lizards) support key predictions. Thus, "suboptimal" is optimal.

46 CFR 169.323 - Furniture and furnishings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... other material having equivalent fire resistant qualities. (e) Trash receptacles must be constructed of non-combustible materials with solid sides and bottoms and have solid noncombustible covers. Rails and...

46 CFR 169.323 - Furniture and furnishings.

Code of Federal Regulations, 2013 CFR

2013-10-01

... other material having equivalent fire resistant qualities. (e) Trash receptacles must be constructed of non-combustible materials with solid sides and bottoms and have solid noncombustible covers. Rails and...

46 CFR 169.323 - Furniture and furnishings.

Code of Federal Regulations, 2014 CFR

2014-10-01

... other material having equivalent fire resistant qualities. (e) Trash receptacles must be constructed of non-combustible materials with solid sides and bottoms and have solid noncombustible covers. Rails and...

The Iron Abundance of IOTA Herculis From Ultraviolet Iron Lines

NASA Astrophysics Data System (ADS)

Grigsby, J.; Mulliss, C.; Baer, G.

1995-03-01

We have obtained (Adelman 1992, 1993, private comunication) coadded, high-resolution IUE spectra of Iota Herculis (B3 IV) in both short wavelength (SWP) and long wavelength (LWP) regions. The spectra span the ultraviolet spectrum from 110 - 300 nm and have a SNR of roughly 30 -50; they are described in Adelman et. al. (1993, ApJ 419, 276). Abundance indicators were 54 lines of Fe II and 26 lines of Fe III whose atomic parameters have been measured in the laboratory. LTE synthetic spectra for comparison with observations were produced with the Kurucz model atmosphere and spectral synthesis codes ATLAS9/SYNTHE (Kurucz 1979, ApJS 40,1; Kurucz and Avrett 1981, SAO Special Report 391). Model parameters were chosen from the literature: effective temperature = 17500 K, log g =3.75, v sin i= 11 km/s, and turbulent velocity = 0 km/s. (Peters and Polidan 1985, in IAU Symposium 111, ed. D. S. Hayes et al. (Dordrecht: Reidel), 417). We determined the equivalent widths of the chosen lines by fitting gaussian profiles to the lines and by measuring the equivalent widths of the gaussians. We derived abundances by fitting a straight line to a plot of observed equivalent widths vs. synthetic equivalent widths; we adjusted the iron abundance of the models until a slope of unity was achieved. The abundances derived from the different ionization stages are in agreement: Fe II lines indicate an iron abundance that is 34 +15/-10% the solar value([Fe/H]=-0.47 +0.16-0.15dex), while from Fe III lines we obtain 34 +/- 10% ([Fe/H]=-0.47 +0.11/-0.15 dex). A search of the literature suggests that no previous investigations of this star's iron abundance have found agreement between the different ionization stages. We thank Saul Adelman for his generous assistance, and the Faculty Research Fund Board of Wittenberg University for support of this research.

Hierarchical data-driven approach to fitting numerical relativity data for nonprecessing binary black holes with an application to final spin and radiated energy

NASA Astrophysics Data System (ADS)

Jiménez-Forteza, Xisco; Keitel, David; Husa, Sascha; Hannam, Mark; Khan, Sebastian; Pürrer, Michael

2017-03-01

Numerical relativity is an essential tool in studying the coalescence of binary black holes (BBHs). It is still computationally prohibitive to cover the BBH parameter space exhaustively, making phenomenological fitting formulas for BBH waveforms and final-state properties important for practical applications. We describe a general hierarchical bottom-up fitting methodology to design and calibrate fits to numerical relativity simulations for the three-dimensional parameter space of quasicircular nonprecessing merging BBHs, spanned by mass ratio and by the individual spin components orthogonal to the orbital plane. Particular attention is paid to incorporating the extreme-mass-ratio limit and to the subdominant unequal-spin effects. As an illustration of the method, we provide two applications, to the final spin and final mass (or equivalently: radiated energy) of the remnant black hole. Fitting to 427 numerical relativity simulations, we obtain results broadly consistent with previously published fits, but improving in overall accuracy and particularly in the approach to extremal limits and for unequal-spin configurations. We also discuss the importance of data quality studies when combining simulations from diverse sources, how detailed error budgets will be necessary for further improvements of these already highly accurate fits, and how this first detailed study of unequal-spin effects helps in choosing the most informative parameters for future numerical relativity runs.

A randomized controlled trial of a multicomponent, targeted, low-literacy educational intervention compared with a nontargeted intervention to boost colorectal cancer screening with fecal immunochemical testing in community clinics.

PubMed

Davis, Stacy N; Christy, Shannon M; Chavarria, Enmanuel A; Abdulla, Rania; Sutton, Steven K; Schmidt, Alyssa R; Vadaparampil, Susan T; Quinn, Gwendolyn P; Simmons, Vani N; Ufondu, Chukwudi B; Ravindra, Chitra; Schultz, Ida; Roetzheim, Richard G; Shibata, David; Meade, Cathy D; Gwede, Clement K

2017-04-15

The objective of the current study was to improve colorectal cancer (CRC) screening uptake with the fecal immunochemical test (FIT). The current study investigated the differential impact of a multicomponent, targeted, low-literacy educational intervention compared with a standard, nontargeted educational intervention. Patients aged 50 to 75 years who were of average CRC risk and not up-to-date with CRC screening were recruited from either a federally qualified health center or a primary care community health clinic. Patients were randomized to the intervention condition (targeted photonovella booklet/DVD plus FIT kit) or comparison condition (standard Centers for Disease Control and Prevention brochure plus FIT kit). The main outcome was screening with FIT within 180 days of delivery of the intervention. Of the 416 participants, 54% were female; the participants were racially and ethnically diverse (66% white, 10% Hispanic, and 28% African American), predominantly of low income, and insured (the majority had county health insurance). Overall, the FIT completion rate was 81%, with 78.1% of participants in the intervention versus 83.5% of those in the comparison condition completing FIT (P =  .17). In multivariate analysis, having health insurance was found to be the primary factor predicting a lack of FIT screening (adjusted odds ratio, 2.10; 95% confidence interval, 1.04-4.26 [P =  .04]). The multicomponent, targeted, low-literacy materials were not found to be significantly different or more effective in increasing FIT uptake compared with the nontargeted materials. Provision of a FIT test plus education may provide a key impetus to improve the completion of CRC screening. The type of educational material (targeted vs nontargeted) may matter less. The findings of the current study provide a unique opportunity for clinics to adopt FIT and to choose the type of patient education materials based on clinic, provider, and patient preferences. Cancer 2017;123:1390-1400. © 2016 American Cancer Society. © 2016 American Cancer Society.

Neuronal boost to evolutionary dynamics.

PubMed

de Vladar, Harold P; Szathmáry, Eörs

2015-12-06

Standard evolutionary dynamics is limited by the constraints of the genetic system. A central message of evolutionary neurodynamics is that evolutionary dynamics in the brain can happen in a neuronal niche in real time, despite the fact that neurons do not reproduce. We show that Hebbian learning and structural synaptic plasticity broaden the capacity for informational replication and guided variability provided a neuronally plausible mechanism of replication is in place. The synergy between learning and selection is more efficient than the equivalent search by mutation selection. We also consider asymmetric landscapes and show that the learning weights become correlated with the fitness gradient. That is, the neuronal complexes learn the local properties of the fitness landscape, resulting in the generation of variability directed towards the direction of fitness increase, as if mutations in a genetic pool were drawn such that they would increase reproductive success. Evolution might thus be more efficient within evolved brains than among organisms out in the wild.

An astronomer's guide to period searching

NASA Astrophysics Data System (ADS)

Schwarzenberg-Czerny, A.

2003-03-01

We concentrate on analysis of unevenly sampled time series, interrupted by periodic gaps, as often encountered in astronomy. While some of our conclusions may appear surprising, all are based on classical statistical principles of Fisher & successors. Except for discussion of the resolution issues, it is best for the reader to forget temporarily about Fourier transforms and to concentrate on problems of fitting of a time series with a model curve. According to their statistical content we divide the issues into several sections, consisting of: (ii) statistical numerical aspects of model fitting, (iii) evaluation of fitted models as hypotheses testing, (iv) the role of the orthogonal models in signal detection (v) conditions for equivalence of periodograms (vi) rating sensitivity by test power. An experienced observer working with individual objects would benefit little from formalized statistical approach. However, we demonstrate the usefulness of this approach in evaluation of performance of periodograms and in quantitative design of large variability surveys.

On Using Surrogates with Genetic Programming.

PubMed

Hildebrandt, Torsten; Branke, Jürgen

2015-01-01

One way to accelerate evolutionary algorithms with expensive fitness evaluations is to combine them with surrogate models. Surrogate models are efficiently computable approximations of the fitness function, derived by means of statistical or machine learning techniques from samples of fully evaluated solutions. But these models usually require a numerical representation, and therefore cannot be used with the tree representation of genetic programming (GP). In this paper, we present a new way to use surrogate models with GP. Rather than using the genotype directly as input to the surrogate model, we propose using a phenotypic characterization. This phenotypic characterization can be computed efficiently and allows us to define approximate measures of equivalence and similarity. Using a stochastic, dynamic job shop scenario as an example of simulation-based GP with an expensive fitness evaluation, we show how these ideas can be used to construct surrogate models and improve the convergence speed and solution quality of GP.

Determination of uronic acids in isolated hemicelluloses from kenaf using diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) and the curve-fitting deconvolution method.

PubMed

Batsoulis, A N; Nacos, M K; Pappas, C S; Tarantilis, P A; Mavromoustakos, T; Polissiou, M G

2004-02-01

Hemicellulose samples were isolated from kenaf (Hibiscus cannabinus L.). Hemicellulosic fractions usually contain a variable percentage of uronic acids. The uronic acid content (expressed in polygalacturonic acid) of the isolated hemicelluloses was determined by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and the curve-fitting deconvolution method. A linear relationship between uronic acids content and the sum of the peak areas at 1745, 1715, and 1600 cm(-1) was established with a high correlation coefficient (0.98). The deconvolution analysis using the curve-fitting method allowed the elimination of spectral interferences from other cell wall components. The above method was compared with an established spectrophotometric method and was found equivalent for accuracy and repeatability (t-test, F-test). This method is applicable in analysis of natural or synthetic mixtures and/or crude substances. The proposed method is simple, rapid, and nondestructive for the samples.

Environmental Effects on Non-oxide Ceramics

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Opila, Elizabeth J.

1997-01-01

Non-oxide ceramics such as silicon carbide (SiC) and silicon nitride (Si3N4) are promising materials for a wide range of high temperature applications. These include such diverse applications as components for heat engines, high temperature electronics, and re-entry shields for space vehicles. Table I lists a number of selected applications. Most of the emphasis here will be on SiC and Si3N4. Where appropriate, other non-oxide materials such as aluminum nitride (AlN) and boron nitride (BN) will be discussed. Proposed materials include both monolithic ceramics and composites. Composites are treated in more detail elsewhere in this volume, however, many of the oxidation/corrosion reactions discussed here can be extended to composites. In application these materials will be exposed to a wide variety of environments. Table I also lists reactive components of these environments.It is well-known that SiC and Si3N4 retain their strength to high temperatures. Thus these materials have been proposed for a variety of hot-gas-path components in combustion applications. These include heat exchanger tubes, combustor liners, and porous filters for coal combustion products. All combustion gases contain CO2, CO, H2, H2O, O2, and N2. The exact gas composition is dependent on the fuel to air ratio or equivalence ratio. (Equivalence ratio (EQ) is a fuel-to-air ratio, with total hydrocarbon content normalized to the amount of O2 and defined by EQ=1 for complete combustion to CO2 and H2O). Figure 1 is a plot of equilibrium gas composition vs. equivalence ratio. Note that as a general rule, all combustion atmospheres are about 10% water vapor and 10% CO2. The amounts of CO, H2, and O2 are highly dependent on equivalence ratio.

[Development and equivalence evaluation of spondee lists of mandarin speech test materials].

PubMed

Zhang, Hua; Wang, Shuo; Wang, Liang; Chen, Jing; Chen, Ai-ting; Guo, Lian-sheng; Zhao, Xiao-yan; Ji, Chen

2006-06-01

To edit the spondee (disyllable) word lists as a part of mandarin speech test materials (MSTM). These will be basic speech materials for routine tests in clinics and laboratories. Two groups of professionals (audiologists, Chinese and Mandarin scientists, linguistician and statistician) were set up at first. The editing principles were established after 3 round table meetings. Ten spondee lists, each with 50 words, were edited and recorded into cassettes. All lists were phonemically balanced (3-dimensions: vowels, consonants and Chinese tones). Seventy-three normal hearing college students were tested. The speech was presented by earphone monaurally. Three statistic methods were used for equivalent analysis. Related analysis showed that all lists were much related, except List 5. Cluster analysis showed that all ten lists could be classified as two groups. But Kappa test showed that the lists' homogeneity were not well. Spondee lists are one of the most routine speech test materials. Their editing, recording and equivalent evaluation are affected by many factors. This also needs multi-discipline cooperation. All lists edited in present study need future modification in recording and testing in order to be used clinically and in research. The phonemic balance should be kept.

Agglomeration of Non-metallic Inclusions at Steel/Ar Interface: In- Situ Observation Experiments and Model Validation

NASA Astrophysics Data System (ADS)

Mu, Wangzhong; Dogan, Neslihan; Coley, Kenneth S.

2017-10-01

Better understanding of agglomeration behavior of nonmetallic inclusions in the steelmaking process is important to control the cleanliness of the steel. In this work, a revision on the Paunov simplified model has been made according to the original Kralchevsky-Paunov model. Thus, this model has been applied to quantitatively calculate the attractive capillary force on inclusions agglomerating at the liquid steel/gas interface. Moreover, the agglomeration behavior of Al2O3 inclusions at a low carbon steel/Ar interface has been observed in situ by high-temperature confocal laser scanning microscopy (CLSM). The velocity and acceleration of inclusions and attractive forces between Al2O3 inclusions of various sizes were calculated based on the CLSM video. The results calculated using the revised model offered a reasonable fit with the present experimental data for different inclusion sizes. Moreover, a quantitative comparison was made between calculations using the equivalent radius of a circle and those using the effective radius. It was found that the calculated capillary force using equivalent radius offered a better fit with the present experimental data because of the inclusion characteristics. Comparing these results with other studies in the literature allowed the authors to conclude that when applied in capillary force calculations, the equivalent radius is more suitable for inclusions with large size and irregular shape, and the effective radius is more appropriate for inclusions with small size or a large shape factor. Using this model, the effect of inclusion size on attractive capillary force has been investigated, demonstrating that larger inclusions are more strongly attracted.

Dealing with missing data: An inpainting application to the MICROSCOPE space mission

NASA Astrophysics Data System (ADS)

Bergé, Joel; Pires, Sandrine; Baghi, Quentin; Touboul, Pierre; Métris, Gilles

2015-12-01

Missing data are a common problem in experimental and observational physics. They can be caused by various sources, such as an instrument's saturation, a contamination from an external event, or a data loss. In particular, they can have a disastrous effect when one is seeking to characterize a colored-noise-dominated signal in Fourier space, since they create a spectral leakage that can artificially increase the noise. It is therefore important to either take them into account or to correct for them prior to, e.g., a least-square fit of the signal to be characterized. In this paper, we present an application of the inpainting algorithm to mock MICROSCOPE data. Inpainting is based on a sparsity assumption, and has already been used in various astrophysical contexts; MICROSCOPE is a French Space Agency mission (whose launch is expected in 2016) that aims to test the weak equivalence principle down to the 1 0-15 level. We then explore the inpainting dependence on the number of gaps and the total fraction of missing values. We show that, in a worst-case scenario, after reconstructing missing values with inpainting a least-square fit may allow us to significantly measure a 1.1 ×10-15 equivalence principle violation signal, which is sufficiently close to the MICROSCOPE requirements to implement inpainting in the official MICROSCOPE data processing and analysis pipeline. Together with the previously published KARMA method, inpainting will then allow us to independently characterize and cross-check an equivalence principle violation signal detection down to the 1 0-15 level.

Multilayer Composite Pressure Vessels

NASA Technical Reports Server (NTRS)

DeLay, Tom

2005-01-01

A method has been devised to enable the fabrication of lightweight pressure vessels from multilayer composite materials. This method is related to, but not the same as, the method described in gMaking a Metal- Lined Composite-Overwrapped Pressure Vessel h (MFS-31814), NASA Tech Briefs, Vol. 29, No. 3 (March 2005), page 59. The method is flexible in that it poses no major impediment to changes in tank design and is applicable to a wide range of tank sizes. The figure depicts a finished tank fabricated by this method, showing layers added at various stages of the fabrication process. In the first step of the process, a mandrel that defines the size and shape of the interior of the tank is machined from a polyurethane foam or other suitable lightweight tooling material. The mandrel is outfitted with metallic end fittings on a shaft. Each end fitting includes an outer flange that has a small step to accommodate a thin layer of graphite/epoxy or other suitable composite material. The outer surface of the mandrel (but not the fittings) is covered with a suitable release material. The composite material is filament- wound so as to cover the entire surface of the mandrel from the step on one end fitting to the step on the other end fitting. The composite material is then cured in place. The entire workpiece is cut in half in a plane perpendicular to the axis of symmetry at its mid-length point, yielding two composite-material half shells, each containing half of the foam mandrel. The halves of the mandrel are removed from within the composite shells, then the shells are reassembled and bonded together with a belly band of cured composite material. The resulting composite shell becomes a mandrel for the subsequent steps of the fabrication process and remains inside the final tank. The outer surface of the composite shell is covered with a layer of material designed to be impermeable by the pressurized fluid to be contained in the tank. A second step on the outer flange of each end fitting accommodates this layer. Depending on the application, this layer could be, for example, a layer of rubber, a polymer film, or an electrodeposited layer of metal. If the fluid to be contained in the tank is a gas, then the best permeation barrier is electrodeposited metal (typically copper or nickel), which can be effective at a thickness of as little as 0.005 in (.0.13 mm). The electrodeposited metal becomes molecularly bonded to the second step on each metallic end fitting. The permeation-barrier layer is covered with many layers of filament-wound composite material, which could be the same as, or different from, the composite material of the inner shell. Finally, the filament-wound composite material is cured in an ov

A new class of sonic composites

NASA Astrophysics Data System (ADS)

Munteanu, Ligia; Chiroiu, Veturia; Donescu, Ştefania; Brişan, Cornel

2014-03-01

Transformation acoustics opens a new avenue towards the architecture, modeling and simulation of a new class of sonic composites with scatterers made of various materials and having various shapes embedded in an epoxy matrix. The design of acoustic scatterers is based on the property of Helmholtz equations to be invariant under a coordinate transformation, i.e., a specific spatial compression is equivalent to a new material in a new space. In this paper, the noise suppression for a wide full band-gap of frequencies is discussed for spherical shell scatterers made of auxetic materials (materials with negative Poisson's ratio). The original domain consists of spheres made from conventional foams with positive Poisson's ratio. The spatial compression is controlled by the coordinate transformation, and leads to an equivalent domain filled with an auxetic material. The coordinate transformation is strongly supported by the manufacturing of auxetics which is based on the pore size reduction through radial compression molds.

10 CFR 30.4 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Commission has entered into an effective agreement under subsection 274b. of the Act. Non-agreement State... access control measures that are not related to the safe use of, or security of, radiological materials... equivalent means the sum of the products of the dose equivalent to the organ or tissue and the weighting...

Equivalent weight of humic acid from peat

USGS Publications Warehouse

Pommer, A.M.; Breger, I.A.

1960-01-01

By means of discontinuous titration, the equivalent weight of humic acid isolated from a peat was found to increase from 144 to 183 between the third and fifty-second day after the humic acid was dissolved. Infra-red studies showed that the material had probably condensed with loss of carbonyl groups. ?? 1960.

Safety Characteristics of Lithium Primary and Secondary Battery Systems. Formulation of a Lithium Battery Safety Matrix

DTIC Science & Technology

1986-07-01

bags. 3) Cushioning of mineral wool , vermiculite or equivalent. Required labeling FLAMMABLE SOLID FLAMMABLE SOLID and DANGEROUS WHEN WET Authorized modes...or equivalent material such as mineral wool . Only permitted, hazardous waste transport companies may carry lithium batteries for disposal. The

Teaching Generatively: Learning about Disorders and Disabilities

ERIC Educational Resources Information Center

Alter, Margaret M.; Borrero, John C.

2015-01-01

Stimulus equivalence procedures have been used to teach course material in higher education in the laboratory and in the classroom. The current study was a systematic replication of Walker, Rehfeldt, and Ninness (2010), who used a stimulus equivalence procedure to train information pertaining to 12 disorders. Specifically, we conducted (a) a…

78 FR 21632 - International Mail Product

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-11

... of United States Postal Service Filing of a Functionally Equivalent International Business Reply...' Decision No. 08-24; and Attachment 4--an application for non-public treatment of materials filed under seal... equivalent to the baseline agreement filed in Docket No. CP2011-59 because it shares similar cost and market...

30 CFR 75.337 - Construction and repair of seals.

Code of Federal Regulations, 2010 CFR

2010-07-01

... record shall be countersigned by the mine foreman or equivalent mine official by the end of the mine foreman's or equivalent mine official's next regularly scheduled working shift. The record shall be kept... quality control results to the District Manager for seal material properties specified by § 75.335 within...

30 CFR 75.337 - Construction and repair of seals.

Code of Federal Regulations, 2011 CFR

2011-07-01

... record shall be countersigned by the mine foreman or equivalent mine official by the end of the mine foreman's or equivalent mine official's next regularly scheduled working shift. The record shall be kept... quality control results to the District Manager for seal material properties specified by § 75.335 within...

Theoretical and experimental characterization of novel water-equivalent plastics in clinical high-energy carbon-ion beams

NASA Astrophysics Data System (ADS)

Lourenço, A.; Wellock, N.; Thomas, R.; Homer, M.; Bouchard, H.; Kanai, T.; MacDougall, N.; Royle, G.; Palmans, H.

2016-11-01

Water-equivalent plastics are frequently used in dosimetry for experimental simplicity. This work evaluates the water-equivalence of novel water-equivalent plastics specifically designed for light-ion beams, as well as commercially available plastics in a clinical high-energy carbon-ion beam. A plastic- to-water conversion factor {{H}\\text{pl,w}} was established to derive absorbed dose to water in a water phantom from ionization chamber readings performed in a plastic phantom. Three trial plastic materials with varying atomic compositions were produced and experimentally characterized in a high-energy carbon-ion beam. Measurements were performed with a Roos ionization chamber, using a broad un-modulated beam of 11  ×  11 cm2, to measure the plastic-to-water conversion factor for the novel materials. The experimental results were compared with Monte Carlo simulations. Commercially available plastics were also simulated for comparison with the plastics tested experimentally, with particular attention to the influence of nuclear interaction cross sections. The measured H\\text{pl,w}\\exp correction increased gradually from 0% at the surface to 0.7% at a depth near the Bragg peak for one of the plastics prepared in this work, while for the other two plastics a maximum correction of 0.8%-1.3% was found. Average differences between experimental and numerical simulations were 0.2%. Monte Carlo results showed that for polyethylene, polystyrene, Rando phantom soft tissue and A-150, the correction increased from 0% to 2.5%-4.0% with depth, while for PMMA it increased to 2%. Water-equivalent plastics such as, Plastic Water, RMI-457, Gammex 457-CTG, WT1 and Virtual Water, gave similar results where maximum corrections were of the order of 2%. Considering the results from Monte Carlo simulations, one of the novel plastics was found to be superior in comparison with the plastic materials currently used in dosimetry, demonstrating that it is feasible to tailor plastic materials to be water-equivalent for carbon ions specifically.

"Doing for Group Exercise What McDonald's Did for Hamburgers": Les Mills, and the Fitness Professional as Global Traveller

ERIC Educational Resources Information Center

Andreasson, Jesper; Johansson, Thomas

2016-01-01

This article analyses fitness professionals' perceptions and understanding of their occupational education and pedagogical pursuance, framed within the emergence of a global fitness industry. The empirical material consists of interviews with personal trainers and group fitness instructors, as well as observations in their working environment. In…

Dissolution kinetics of soluble nondisintegrating disks.

PubMed

de Blaey, C J; van der Graaff, H

1977-12-01

An equation describing the isotropical dissolution of soluble nondisintegrating disks was developed. It was equivalent to the cube root law only if the height and diameter of the disk were equal. The dissolution kinetics of sodium chloride disks were examined, using a beaker equipped with a centrifugal stirrer as the dissolution chamber. The fit of the experimental data to the cube root law had a coefficient of variation of about 4-5%. It was demonstrated statistically that a fit to a square root of mass versus time relation was significantly better. With increasing porosity, the dissolution process proceeded faster than predicted on the basis of the diffusion-convection model. An explanation is proposed by assuming an increased effective dissolution surface.

Mass loss in the 96 day binary UU Cancri

NASA Technical Reports Server (NTRS)

Eaton, Joel A.; Hall, Douglas S.; Honeycutt, R. K.

1991-01-01

A series of 16 high-dispersion spectra at H-alpha have been obtained for the tidally distorted K giant-containing long-period binary UU Cnc, in order to both study the K giant's Doppler profiles and search for the effects of accretion onto the second component. While Doppler profiles of the system for a semidetached configuration fit the observations very well, those for existing overcontact light-curve solutions all yield poorer fits. Although the H-alpha line is always stronger than those of the common giants, its equivalent width is consistent with a K4 II classification reflective of the star's 50 solar radius size. Emission wings in H-alpha are possible evidence for an accretion disk.

Equal Area Logistic Estimation for Item Response Theory

NASA Astrophysics Data System (ADS)

Lo, Shih-Ching; Wang, Kuo-Chang; Chang, Hsin-Li

2009-08-01

Item response theory (IRT) models use logistic functions exclusively as item response functions (IRFs). Applications of IRT models require obtaining the set of values for logistic function parameters that best fit an empirical data set. However, success in obtaining such set of values does not guarantee that the constructs they represent actually exist, for the adequacy of a model is not sustained by the possibility of estimating parameters. In this study, an equal area based two-parameter logistic model estimation algorithm is proposed. Two theorems are given to prove that the results of the algorithm are equivalent to the results of fitting data by logistic model. Numerical results are presented to show the stability and accuracy of the algorithm.

Equivalent source modeling of the core magnetic field using magsat data

NASA Technical Reports Server (NTRS)

Mayhew, M. A.; Estes, R. H.

1983-01-01

Experiments are carried out on fitting the main field using different numbers of equivalent sources arranged in equal area at fixed radii at and inside the core-mantle boundary. In fixing the radius for a given series of runs, the convergence problems that result from the extreme nonlinearity of the problem when dipole positions are allowed to vary are avoided. Results are presented from a comparison between this approach and the standard spherical harmonic approach for modeling the main field in terms of accuracy and computational efficiency. The modeling of the main field with an equivalent dipole representation is found to be comparable to the standard spherical harmonic approach in accuracy. The 32 deg dipole density (42 dipoles) corresponds approximately to an eleventh degree/order spherical harmonic expansion (143 parameters), whereas the 21 dipole density (92 dipoles) corresponds to approximately a seventeenth degree and order expansion (323 parameters). It is pointed out that fixing the dipole positions results in rapid convergence of the dipole solutions for single-epoch models.

Experimental study and finite element analysis based on equivalent load method for laser ultrasonic measurement of elastic constants.

PubMed

Zhan, Yu; Liu, Changsheng; Zhang, Fengpeng; Qiu, Zhaoguo

2016-07-01

The laser ultrasonic generation of Rayleigh surface wave and longitudinal wave in an elastic plate is studied by experiment and finite element method. In order to eliminate the measurement error and the time delay of the experimental system, the linear fitting method of experimental data is applied. The finite element analysis software ABAQUS is used to simulate the propagation of Rayleigh surface wave and longitudinal wave caused by laser excitation on a sheet metal sample surface. The equivalent load method is proposed and applied. The pulsed laser is equivalent to the surface load in time and space domain to meet the Gaussian profile. The relationship between the physical parameters of the laser and the load is established by the correction factor. The numerical solution is in good agreement with the experimental result. The simple and effective numerical and experimental methods for laser ultrasonic measurement of the elastic constants are demonstrated. Copyright © 2016. Published by Elsevier B.V.

SU-C-9A-04: Alternative Analytic Solution to the Paralyzable Detector Model to Calculate Deadtime and Deadtime Loss

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

Siman, W; Kappadath, S

2014-06-01

Purpose: Some common methods to solve for deadtime are (1) dual-source method, which assumes two equal activities; (2) model fitting, which requires multiple acquisitions as source decays; and (3) lossless model, which assumes no deadtime loss at low count rates. We propose a new analytic alternative solution to calculate deadtime for paralyzable gamma camera. Methods: Deadtime T can be calculated analytically from two distinct observed count rates M1 and M2 when the ratio of the true count rates alpha=N2/N1 is known. Alpha can be measured as a ratio of two measured activities using dose calibrators or via radioactive decay. Knowledgemore » of alpha creates a system with 2 equations and 2 unknowns, i.e., T and N1. To verify the validity of the proposed method, projections of a non-uniform phantom (4GBq 99mTc) were acquired in using Siemens SymbiaS multiple times over 48 hours. Each projection has >100kcts. The deadtime for each projection was calculated by fitting the data to a paralyzable model and also by using the proposed 2-acquisition method. The two estimates of deadtime were compared using the Bland-Altmann method. In addition, the dependency of uncertainty in T on uncertainty in alpha was investigated for several imaging conditions. Results: The results strongly suggest that the 2-acquisition method is equivalent to the fitting method. The Bland-Altman analysis yielded mean difference in deadtime estimate of ∼0.076us (95%CI: -0.049us, 0.103us) between the 2-acquisition and model fitting methods. The 95% limits of agreement were calculated to be -0.104 to 0.256us. The uncertainty in deadtime calculated using the proposed method is highly dependent on the uncertainty in the ratio alpha. Conclusion: The 2-acquisition method was found to be equivalent to the parameter fitting method. The proposed method offers a simpler and more practical way to analytically solve for a paralyzable detector deadtime, especially during physics testing.« less

[Modeling and experimental study on frequency-domain electricity properties of biological materials].

PubMed

Tian, Hua; Luo, Shiqiang; Zhang, Rui; Yang, Gang; Huang, Hua

2009-12-01

Frequency-domain electricity properties of four objects, including bullfrog skin, bullfrog muscle, triply distilled water and 0.9% NaCl, were tested in the range of 100Hz-10MHz using home-made electrode and measuring system. The experimental results showed that the resistance of 0.9% NaCl decreased dramatically, that the amplitude frequency characteristics of bullfrog's muscle and skin were similar, but that of triply distilled water did not change significantly. The frequency dependence of 0.9% NaCl showed that the electrode had great influence on the measuring system, so a new equivalent circuit model based on the electrode system was needed. These findings suggest that the new five-parameter equivalent circuit model, which embodies considerations on the interaction between electrodes and tissues, is a reasonable equivalent circuit for studying the electrical characteristics of biological materials.

Effect of top-down nanomachining on electrical conduction properties of TiO2 nanostructure-based chemical sensors.

PubMed

Francioso, L; De Pascali, C; Capone, S; Siciliano, P

2012-03-09

The present research was motivated by the growing interest of the scientific community towards the understanding of basic gas-surface interaction mechanisms in 1D nanostructured metal oxide semiconductors, whose significantly enhanced chemical detection sensitivity is known. In this work, impedance spectroscopy (IS) was used to evaluate how a top-down patterning of the sensitive layer can modulate the electrical properties of a gas sensor based on a fully integrated nanometric array of TiO(2) polycrystalline strips. The aim of the study was supported by comparative experimental activity carried out on different thin film gas sensors based on identical TiO(2) polycrystalline sensitive thin films. The impedance responses of the investigated devices under dry air (as the reference environment) and ethanol vapors (as the target gas) were fitted by a complex nonlinear least-squares method using LEVM software, in order to find an appropriate equivalent circuit describing the main conduction processes involved in the gas/semiconductor interactions. Two different equivalent circuit models were identified as completely representative of the TiO(2) thin film and the TiO(2) nanostructure-based gas sensors, respectively. All the circuit parameters were quantified and the related standard deviations were evaluated. The simulated results well approximated the experimental data as indicated by the small mean errors of the fits (in the range of 10(-4)) and the small standard deviations of the circuit parameters. In addition to the substrate capacitance, three different contributions to the overall conduction mechanism were identified for both equivalent circuits: bulk conductivity, intergrain contact and semiconductor-electrode contact, electrically represented by an ideal resistor R(g), a parallel R(gb)C(gb) block and a parallel R(c)-CPE(c) combination, respectively. In terms of equivalent circuit modeling, the sensitive layer patterning introduced an additional parameter in parallel connection with the whole circuit block. Such a circuit element (an ideal inductor, L) has an average value of about 125 μH and exhibits no direct dependence on the analyte gas concentration. Its presence could be due to complex mutual inductance effects occurring both between all the adjacent nanostrips (10 µm spaced) and between the nanostrips and the n-type-doped silicon substrate underneath the thermal oxide (wire/plate effect), where a two order of magnitude higher magnetic permeability of silicon can give L values comparable with those estimated by the fitting procedure. Slightly modified experimental models confirmed that the theoretical background, regulating thin film devices based on metal oxide semiconductors, is also valid for nanopatterned devices.

Analytic solutions to modelling exponential and harmonic functions using Chebyshev polynomials: fitting frequency-domain lifetime images with photobleaching.

PubMed

Malachowski, George C; Clegg, Robert M; Redford, Glen I

2007-12-01

A novel approach is introduced for modelling linear dynamic systems composed of exponentials and harmonics. The method improves the speed of current numerical techniques up to 1000-fold for problems that have solutions of multiple exponentials plus harmonics and decaying components. Such signals are common in fluorescence microscopy experiments. Selective constraints of the parameters being fitted are allowed. This method, using discrete Chebyshev transforms, will correctly fit large volumes of data using a noniterative, single-pass routine that is fast enough to analyse images in real time. The method is applied to fluorescence lifetime imaging data in the frequency domain with varying degrees of photobleaching over the time of total data acquisition. The accuracy of the Chebyshev method is compared to a simple rapid discrete Fourier transform (equivalent to least-squares fitting) that does not take the photobleaching into account. The method can be extended to other linear systems composed of different functions. Simulations are performed and applications are described showing the utility of the method, in particular in the area of fluorescence microscopy.

Accuracy of maximum likelihood and least-squares estimates in the lidar slope method with noisy data.

PubMed

Eberhard, Wynn L

2017-04-01

The maximum likelihood estimator (MLE) is derived for retrieving the extinction coefficient and zero-range intercept in the lidar slope method in the presence of random and independent Gaussian noise. Least-squares fitting, weighted by the inverse of the noise variance, is equivalent to the MLE. Monte Carlo simulations demonstrate that two traditional least-squares fitting schemes, which use different weights, are less accurate. Alternative fitting schemes that have some positive attributes are introduced and evaluated. The principal factors governing accuracy of all these schemes are elucidated. Applying these schemes to data with Poisson rather than Gaussian noise alters accuracy little, even when the signal-to-noise ratio is low. Methods to estimate optimum weighting factors in actual data are presented. Even when the weighting estimates are coarse, retrieval accuracy declines only modestly. Mathematical tools are described for predicting retrieval accuracy. Least-squares fitting with inverse variance weighting has optimum accuracy for retrieval of parameters from single-wavelength lidar measurements when noise, errors, and uncertainties are Gaussian distributed, or close to optimum when only approximately Gaussian.

Calculation of equivalent friction coefficient for castor seed by single screw press

NASA Astrophysics Data System (ADS)

Liu, R.; Xiao, Z.; Li, C.; Zhang, L.; Li, P.; Li, H.; Zhang, A.; Tang, S.; Sun, F.

2017-08-01

Based on the traction angle and transportation rate equation, castor beans were pressed by application of single screw under different cake diameter and different screw speed. The results showed that the greater the cake diameter and screw rotation speed, the greater the actual transmission rate was. The equivalent friction coefficient was defined and calculated as 0.4136, and the friction coefficients between press material and screw, bar cage were less than the equivalent friction coefficient value.

Thermally driven piston assembly and position control therefor

NASA Technical Reports Server (NTRS)

Thomsen, III, Donald L. (Inventor); Bryant, Robert G. (Inventor)

2010-01-01

A thermally driven piston assembly's housing has (i) a first material slidingly fitted therein, and (ii) at least one plug of a second material slidingly fitted therein and abutting the first material. The first material is one (e.g., a liquid crystal elastomer) that undergoes a stiffness change and/or a dimensional change when subjected to a temperature change in the temperature range of interest. When subjected to the temperature change while in the housing, the first material is restricted to changing dimensionally along a single dimension. The second material retains its shape and size throughout the temperature range of interest. As a result, the plug moves in the housing in correspondence with the dimensional change of the first material or the plug's movement is damped by the stiffness change of the first material.

Size of Undergraduate Physics and Astronomy Programs: Data from the AIP Enrollments and Degrees and Academic Workforce Surveys. Focus On

ERIC Educational Resources Information Center

Mulvey, Patrick; Tyler, John; Nicholson, Starr; Ivie, Rachel

2017-01-01

This report provides data on the size of degree-granting physics and astronomy departments by examining the number of bachelor's degrees awarded and the number of full-time equivalent (FTE) faculty members employed. The benchmarking data in this report is intended to allow physics and astronomy departments to see how they fit in the national…

Particle Density Substitution Method for Trafficability of Soil in Different Gravity Environments

NASA Astrophysics Data System (ADS)

Huang, Chuan; Gao, Feng; Xie, Xiaolin; Jiang, Hui; Zeng, Wen

2017-12-01

By selecting metal powders with comparable particle size class, similar shape and material and almost the same void ratio but different particle densities, the influence of different gravity on the trafficability of soil under different states of gravitational fields is found to be equivalent to the change in particle density. This method is named particle density substitution. The shearing and bearing characteristics of simulated soil were studied. An influence of different factors on the experimental results was achieved, and a minimal influence of factors other than particle density on experimental results was obtained. Regression of shearing and bearing characteristics of the simulated soil was designed. The relationship between particle density and mechanical parameters of soil was fitted with curves. The formulation between particle density and maximal static thrust was established. By analyzing these data, the maximal static thrust slowly decreased with increasing particle density, reached the minimum when particle density was 3 g/cm3, and then sharply increased. This trend is consistent with the theoretical result. It can also certify that the particle density substitution method established here is reasonable.

Study of the Effect on Ionic Conductivity and Structral Morphology of the SR Doped Lanthanum Gallate Solid Electrolyte

NASA Astrophysics Data System (ADS)

Sood, Kapil; Singh, K.; Pandey, O. P.

2013-07-01

In the present study, lanthanum gallate and Sr-doped lanthanum gallate samples were prepared by conventional solid state reaction method. The phase conformation has been performed by using X-ray diffraction (XRD) study. The elemental composition has been confirmed using energy dispersive spectroscopy (EDS) analysis. Ac conductivity of the samples has been measured in the frequency range 0.1-106 Hz and from 50-800 °C. The impedance plots among real and complex impedances at particular temperature have been discussed. The behavior shows the effect of bulk and grain boundary effects of the doped sample. The impedance plots with frequency have been analyzed. The plots have been well fitted to equivalent circuit model. The conductivity shows the Arrhenius type of behavior. The activation energy has been calculated from the plots and represents that the conductivity through the material is mainly ionic. The structural morphology of the samples has been investigated using scanning electron microscope (SEM). The micrograph shows that the porosity and grain size both decreases with Sr-doping.

In vitro corrosion study by EIS of a nickel-free stainless steel for orthopaedic applications.

PubMed

Rondelli, G; Torricelli, P; Fini, M; Giardino, R

2005-03-01

The electrochemical impedance spectroscopy (EIS) technique was used for the study of the electrochemical behaviour of Ni-free austenitic stainless steel for orthopaedic applications. Experiments were carried out using four different test solutions: (i) phosphate-buffered saline (PBS), (ii) minimum essential medium (MEM), (iii) MEM + 10% fetal calf serum (FCS), (iv) MEM + 10% fetal calf serum + L929 fibroblast cell line (Cell). Bode-phase spectra showed the presence of two maxima and were fitted with an equivalent circuit characterized by two parallel combinations (Resistance, Constant Phase Element). The (R(1), CPE(1)) branch was assigned to the inner compact passive film and the (R(2), CPE(2)) branch to the external porous film. The resistance of the inner film R(1), here directly related to the material's uniform corrosion resistance, raised with the immersion time and increased in the following order: PBS

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

Teka, S.; Gaied, A.; Jaballah, N.

Highlights: • Microwave-assisted synthesis of rotaxane based on anthracene and β-cyclodextrin. • Morphological and optical characterization of thin solid film. • Elaboration of impedimetric gold/rotaxane sensor. • Investigation of the membrane sensitivity towards Hg{sup 2+}, Cu{sup 2+} and Pb{sup 2+} cations. - Abstract: An impedimetric sensor based on a new semi-conducting rotaxane has been described for detection of toxic cations. The rotaxane, consists on a π-conjugated material encapsulated into β-cyclodextrin (β-CD); it has been synthesized via the Williamson reaction under microwaves irradiation. The supramolecular structure of the compound was confirmed by NMR and FT-IR spectroscopies. A thin solid film ofmore » the rotaxane was deposited by spin-coating to develop a new electrochemical sensor. The morphological properties of the organic membrane were evaluated using contact angle measurements and atomic force microscopy. The gold/rotaxane/solution interfaces were investigated by electrochemical impedance spectroscopy and the obtained data were fitted using an equivalent electrical circuit. The response of the gold/rotaxane membrane towards Hg{sup 2+}, Cu{sup 2+} and Pb{sup 2+} cations was studied and the results showed a good sensitivity to the mercury cations.« less

Multiphase model for transformation induced plasticity. Extended Leblond's model

NASA Astrophysics Data System (ADS)

Weisz-Patrault, Daniel

2017-09-01

Transformation induced plasticity (TRIP) classically refers to plastic strains observed during phase transitions that occur under mechanical loads (that can be lower than the yield stress). A theoretical approach based on homogenization is proposed to deal with multiphase changes and to extend the validity of the well known and widely used model proposed by Leblond (1989). The approach is similar, but several product phases are considered instead of one and several assumptions have been released. Thus, besides the generalization for several phases, one can mention three main improvements in the calculation of the local equivalent plastic strain: the deviatoric part of the phase transformation is taken into account, both parent and product phases are elastic-plastic with linear isotropic hardening and the applied stress is considered. Results show that classical issues of singularities arising in the Leblond's model (corrected by ad hoc numerical functions or thresholding) are solved in this contribution excepted when the applied equivalent stress reaches the yield stress. Indeed, in this situation the parent phase is entirely plastic as soon as the phase transformation begins and the same singularity as in the Leblond's model arises. A physical explanation of the cutoff function is introduced in order to regularize the singularity. Furthermore, experiments extracted from the literature dealing with multiphase transitions and multiaxial loads are compared with the original Leblond's model and the proposed extended version. For the extended version, very good agreement is observed without any fitting procedures (i.e., material parameters are extracted from other dedicated experiments) and for the original version results are more qualitative.

Structural Characterization and Impedance Spectroscopy of Substituted, Fused-Ring Organic Semiconductors

NASA Astrophysics Data System (ADS)

Shaw, Charles Michael

Organic materials present a number of advantages over silicon that make them ideal candidates for modest performance devices like active matrix backplanes and RFID tags. The work detailed here describes both structural characterization of promising new materials, as well as the adaptation of impedance spectroscopy techniques to the study of organic transistors. Unit cells and solution casting behavior for dioctyl- and didodecyl-pentathienoacene are presented. Dioctyl pentathienoacene has an orthorhombic lattice with parameters a = 1.15 nm, b = 0.43 nm and c = 3.05 nm. Didodecyl pentathienoacene has an monoclinic lattice with parameters gamma = 92.2°, a = 1.10 urn, b = 0.42 nm and c = 3.89 nm. Additionally, thermotropic phase behavior is detailed. Both materials exhibit a "side chain melting" transition---characterized by a dramatic unit cell contraction of more than 20%---and smectic C liquid crystal phases. The side chain melting transition shows similarity to phase transitions elicited by exposing these materials to high energy electron flux. In both cases, disorder in the substitutions results in new phases for these materials. Dioctyl-pentathienoacene also exhibits a unique phase, which is intermediately ordered and shows a threefold increase in critical dose over the as-cast phase. Impedance spectroscopy of triisopropylsilyl pentacene transistors suggests these devices are well fit by a Voigt model equivalent circuit. The gate bias dependent resistor represents the channel conductance and the capacitor represents the drain-gate and source-gate capacitances. This in turn suggests that conduction occurs through delocalized states available in ordered regions, with disordered regions contributing localized, immobile states. Impedance spectroscopy of poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) shows similar behavior. The use of variable temperature impedance spectroscopy is also demonstrated. This technique is used to measure the reduction in trap energy---from 200 meV to 140 meV---produced by annealing the material in its liquid crystal phase.

Estimating raw material equivalents on a macro-level: comparison of multi-regional input-output analysis and hybrid LCI-IO.

PubMed

Schoer, Karl; Wood, Richard; Arto, Iñaki; Weinzettel, Jan

2013-12-17

The mass of material consumed by a population has become a useful proxy for measuring environmental pressure. The "raw material equivalents" (RME) metric of material consumption addresses the issue of including the full supply chain (including imports) when calculating national or product level material impacts. The RME calculation suffers from data availability, however, as quantitative data on production practices along the full supply chain (in different regions) is required. Hence, the RME is currently being estimated by three main approaches: (1) assuming domestic technology in foreign economies, (2) utilizing region-specific life-cycle inventories (in a hybrid framework), and (3) utilizing multi-regional input-output (MRIO) analysis to explicitly cover all regions of the supply chain. While the first approach has been shown to give inaccurate results, this paper focuses on the benefits and costs of the latter two approaches. We analyze results from two key (MRIO and hybrid) projects modeling raw material equivalents, adjusting the models in a stepwise manner in order to quantify the effects of individual conceptual elements. We attempt to isolate the MRIO gap, which denotes the quantitative impact of calculating the RME of imports by an MRIO approach instead of the hybrid model, focusing on the RME of EU external trade imports. While, the models give quantitatively similar results, differences become more pronounced when tracking more detailed material flows. We assess the advantages and disadvantages of the two approaches and look forward to ways to further harmonize data and approaches.

Cross Section Sensitivity and Propagated Errors in HZE Exposures

NASA Technical Reports Server (NTRS)

Heinbockel, John H.; Wilson, John W.; Blatnig, Steve R.; Qualls, Garry D.; Badavi, Francis F.; Cucinotta, Francis A.

2005-01-01

It has long been recognized that galactic cosmic rays are of such high energy that they tend to pass through available shielding materials resulting in exposure of astronauts and equipment within space vehicles and habitats. Any protection provided by shielding materials result not so much from stopping such particles but by changing their physical character in interaction with shielding material nuclei forming, hopefully, less dangerous species. Clearly, the fidelity of the nuclear cross-sections is essential to correct specification of shield design and sensitivity to cross-section error is important in guiding experimental validation of cross-section models and database. We examine the Boltzmann transport equation which is used to calculate dose equivalent during solar minimum, with units (cSv/yr), associated with various depths of shielding materials. The dose equivalent is a weighted sum of contributions from neutrons, protons, light ions, medium ions and heavy ions. We investigate the sensitivity of dose equivalent calculations due to errors in nuclear fragmentation cross-sections. We do this error analysis for all possible projectile-fragment combinations (14,365 such combinations) to estimate the sensitivity of the shielding calculations to errors in the nuclear fragmentation cross-sections. Numerical differentiation with respect to the cross-sections will be evaluated in a broad class of materials including polyethylene, aluminum and copper. We will identify the most important cross-sections for further experimental study and evaluate their impact on propagated errors in shielding estimates.

Using the Stimulus Equivalence Paradigm to Teach Course Material in an Undergraduate Rehabilitation Course

ERIC Educational Resources Information Center

Walker, Brooke D.; Rehfeldt, Ruth Anne; Ninness, Chris

2010-01-01

In 2 experiments, we examined whether the stimulus equivalence instructional paradigm could be used to teach relations among names, definitions, causes, and common treatments for disabilities using a selection-based intraverbal training format. Participants were pre- and posttested on vocal intraverbal relations and were trained using…

46 CFR 169.563 - Firehose.

Code of Federal Regulations, 2012 CFR

2012-10-01

... or equivalent of not over 11/2 inch diameter or garden hose of not less than 5/8 inch nominal inside diameter. If garden hose is used, it must be of a good commercial grade constructed of an inner rubber tube, plies of braided cotton reinforcement and an outer rubber cover, or of equivalent material, and must be...

46 CFR 169.563 - Firehose.

Code of Federal Regulations, 2014 CFR

2014-10-01

... or equivalent of not over 11/2 inch diameter or garden hose of not less than 5/8 inch nominal inside diameter. If garden hose is used, it must be of a good commercial grade constructed of an inner rubber tube, plies of braided cotton reinforcement and an outer rubber cover, or of equivalent material, and must be...

46 CFR 169.563 - Firehose.

Code of Federal Regulations, 2013 CFR

2013-10-01

... or equivalent of not over 11/2 inch diameter or garden hose of not less than 5/8 inch nominal inside diameter. If garden hose is used, it must be of a good commercial grade constructed of an inner rubber tube, plies of braided cotton reinforcement and an outer rubber cover, or of equivalent material, and must be...

49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... motor vehicles; and non-DOT specification cargo tank motor vehicles equivalent in structural design and...; metal IBCs and non-specification portable tanks equivalent in structural design and accident damage...; Class DOT 106, 110 multi-unit tank car tanks; AAR Class 203W, 206W, 211W tank car tanks; and non-DOT...

49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... motor vehicles; and non-DOT specification cargo tank motor vehicles equivalent in structural design and...; metal IBCs and non-specification portable tanks equivalent in structural design and accident damage...; Class DOT 106, 110 multi-unit tank car tanks; AAR Class 203W, 206W, 211W tank car tanks; and non-DOT...

49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... motor vehicles; and non-DOT specification cargo tank motor vehicles equivalent in structural design and...; metal IBCs and non-specification portable tanks equivalent in structural design and accident damage...; Class DOT 106, 110 multi-unit tank car tanks; AAR Class 203W, 206W, 211W tank car tanks; and non-DOT...

49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

Code of Federal Regulations, 2014 CFR

2014-10-01

... motor vehicles; and non-DOT specification cargo tank motor vehicles equivalent in structural design and...; metal IBCs and non-specification portable tanks equivalent in structural design and accident damage...; Class DOT 106, 110 multi-unit tank car tanks; AAR Class 203W, 206W, 211W tank car tanks; and non-DOT...

Convective Heat Transfer Scaling of Ignition Delay and Burning Rate with Heat Flux and Stretch Rate in the Equivalent Low Stretch Apparatus

NASA Technical Reports Server (NTRS)

Olson, Sandra

2011-01-01

To better evaluate the buoyant contributions to the convective cooling (or heating) inherent in normal-gravity material flammability test methods, we derive a convective heat transfer correlation that can be used to account for the forced convective stretch effects on the net radiant heat flux for both ignition delay time and burning rate. The Equivalent Low Stretch Apparatus (ELSA) uses an inverted cone heater to minimize buoyant effects while at the same time providing a forced stagnation flow on the sample, which ignites and burns as a ceiling fire. Ignition delay and burning rate data is correlated with incident heat flux and convective heat transfer and compared to results from other test methods and fuel geometries using similarity to determine the equivalent stretch rates and thus convective cooling (or heating) rates for those geometries. With this correlation methodology, buoyant effects inherent in normal gravity material flammability test methods can be estimated, to better apply the test results to low stretch environments relevant to spacecraft material selection.

Normal tissue complication probability modeling of radiation-induced hypothyroidism after head-and-neck radiation therapy.

PubMed

Bakhshandeh, Mohsen; Hashemi, Bijan; Mahdavi, Seied Rabi Mehdi; Nikoofar, Alireza; Vasheghani, Maryam; Kazemnejad, Anoshirvan

2013-02-01

To determine the dose-response relationship of the thyroid for radiation-induced hypothyroidism in head-and-neck radiation therapy, according to 6 normal tissue complication probability models, and to find the best-fit parameters of the models. Sixty-five patients treated with primary or postoperative radiation therapy for various cancers in the head-and-neck region were prospectively evaluated. Patient serum samples (tri-iodothyronine, thyroxine, thyroid-stimulating hormone [TSH], free tri-iodothyronine, and free thyroxine) were measured before and at regular time intervals until 1 year after the completion of radiation therapy. Dose-volume histograms (DVHs) of the patients' thyroid gland were derived from their computed tomography (CT)-based treatment planning data. Hypothyroidism was defined as increased TSH (subclinical hypothyroidism) or increased TSH in combination with decreased free thyroxine and thyroxine (clinical hypothyroidism). Thyroid DVHs were converted to 2 Gy/fraction equivalent doses using the linear-quadratic formula with α/β = 3 Gy. The evaluated models included the following: Lyman with the DVH reduced to the equivalent uniform dose (EUD), known as LEUD; Logit-EUD; mean dose; relative seriality; individual critical volume; and population critical volume models. The parameters of the models were obtained by fitting the patients' data using a maximum likelihood analysis method. The goodness of fit of the models was determined by the 2-sample Kolmogorov-Smirnov test. Ranking of the models was made according to Akaike's information criterion. Twenty-nine patients (44.6%) experienced hypothyroidism. None of the models was rejected according to the evaluation of the goodness of fit. The mean dose model was ranked as the best model on the basis of its Akaike's information criterion value. The D(50) estimated from the models was approximately 44 Gy. The implemented normal tissue complication probability models showed a parallel architecture for the thyroid. The mean dose model can be used as the best model to describe the dose-response relationship for hypothyroidism complication. Copyright © 2013 Elsevier Inc. All rights reserved.

Evaluation of a large-scale quantitative respirator-fit testing program for healthcare workers: survey results.

PubMed

Wilkinson, Irene J; Pisaniello, Dino; Ahmad, Junaid; Edwards, Suzanne

2010-09-01

To present the evaluation of a large-scale quantitative respirator-fit testing program. Concurrent questionnaire survey of fit testers and test subjects. Ambulatory care, home nursing care, and acute care hospitals across South Australia. Quantitative facial-fit testing was performed with TSI PortaCount instruments for healthcare workers (HCWs) who wore 5 different models of a disposable P2 (N95-equivalent) respirator. The questionnaire included questions about the HCW's age, sex, race, occupational category, main area of work, smoking status, facial characteristics, prior training and experience in use of respiratory masks, and number of attempts to obtain a respirator fit. A total of 6,160 HCWs were successfully fitted during the period from January through July 2007. Of the 4,472 HCWs who responded to the questionnaire and were successfully fitted, 3,707 (82.9%) were successfully fitted with the first tested respirator, 551 (12.3%) required testing with a second model, and 214 (4.8%) required 3 or more tests. We noted an increased pass rate on the first attempt over time. Asians (excluding those from South and Central Asia) had the highest failure rate (16.3% [45 of 276 Asian HCWs were unsuccessfully fitted]), and whites had the lowest (9.8% [426 of 4,338 white HCWs]). Race was highly correlated with facial shape. Among occupational groups, doctors had the highest failure rate (13.4% [81 of 604 doctors]), but they also had the highest proportion of Asians. Prior education and/or training in respirator use were not associated with a higher pass rate. Certain facial characteristics were associated with higher or lower pass rates with regard to fit testing, and fit testers were able to select a suitable respirator on the basis of a visual assessment in the majority of cases. For the fit tester, training and experience were important factors; however, for the HCW being fitted, prior experience in respirator use was not an important factor.

Authentic Teaching of Fitness Concepts to Children.

ERIC Educational Resources Information Center

Sander, Allan N.; Ratliffe, Thomas; Kane, Jennifer

This paper stresses the importance of teaching aerobic and muscle fitness concepts as part of a health-related fitness curriculum in physical education, recommending outcomes for teaching aerobic endurance and muscle/strength endurance in kindergarten through sixth grade. It describes important learning aid materials and presents national…

Technical note: Equivalent genomic models with a residual polygenic effect.

PubMed

Liu, Z; Goddard, M E; Hayes, B J; Reinhardt, F; Reents, R

2016-03-01

Routine genomic evaluations in animal breeding are usually based on either a BLUP with genomic relationship matrix (GBLUP) or single nucleotide polymorphism (SNP) BLUP model. For a multi-step genomic evaluation, these 2 alternative genomic models were proven to give equivalent predictions for genomic reference animals. The model equivalence was verified also for young genotyped animals without phenotypes. Due to incomplete linkage disequilibrium of SNP markers to genes or causal mutations responsible for genetic inheritance of quantitative traits, SNP markers cannot explain all the genetic variance. A residual polygenic effect is normally fitted in the genomic model to account for the incomplete linkage disequilibrium. In this study, we start by showing the proof that the multi-step GBLUP and SNP BLUP models are equivalent for the reference animals, when they have a residual polygenic effect included. Second, the equivalence of both multi-step genomic models with a residual polygenic effect was also verified for young genotyped animals without phenotypes. Additionally, we derived formulas to convert genomic estimated breeding values of the GBLUP model to its components, direct genomic values and residual polygenic effect. Third, we made a proof that the equivalence of these 2 genomic models with a residual polygenic effect holds also for single-step genomic evaluation. Both the single-step GBLUP and SNP BLUP models lead to equal prediction for genotyped animals with phenotypes (e.g., reference animals), as well as for (young) genotyped animals without phenotypes. Finally, these 2 single-step genomic models with a residual polygenic effect were proven to be equivalent for estimation of SNP effects, too. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Colossal dielectric constants in single-crystalline and ceramic CaCu3Ti4O12 investigated by broadband dielectric spectroscopy

NASA Astrophysics Data System (ADS)

Krohns, S.; Lunkenheimer, P.; Ebbinghaus, S. G.; Loidl, A.

2008-04-01

In the present work, the authors report results of broadband dielectric spectroscopy on various samples of CaCu3Ti4O12 (CCTO), also including single-crystalline material, which so far was only rarely investigated. The measurements extend up to 1.3 GHz, covering more than nine frequency decades. We address the question of the origin of the colossal dielectric constants and of the relaxational behavior in this material, including the second relaxation reported in several recent works. For this purpose, the dependence of the temperature- and frequency-dependent dielectric properties on different tempering and surface treatments of the samples and on ac-field amplitude is investigated. Broadband spectra of a single crystal are analyzed by an equivalent circuit description by assuming two highly resistive layers in series to the bulk. Good fits could be achieved, including the second relaxation, which also shows up in single crystals. The temperature- and frequency-dependent intrinsic conductivity of CCTO is consistent with the variable range hopping model. The second relaxation is sensitive to surface treatment and, in contrast to the main relaxation, is also strongly affected by the applied ac voltage. Concerning the origin of the two insulating layers, we discuss a completely surface-related mechanism by assuming the formation of a metal-insulator diode and a combination of surface and internal barriers.

ZrB 2-HfB 2 solid solutions as electrode materials for hydrogen reaction in acidic and basic solutions

DOE PAGES

Sitler, Steven J.; Raja, Krishnan S.; Charit, Indrajit

2016-11-09

Spark plasma sintered transition metal diborides such as HfB 2, ZrB 2 and their solid solutions were investigated as electrode materials for electrochemical hydrogen evolutions reactions (HER) in 1 M H 2SO 4 and 1 M NaOH electrolytes. HfB 2 and ZrB 2 formed complete solid solutions when mixed in 1:1, 1:4, and 4:1 ratios and they were stable in both electrolytes. The HER kinetics of the diborides were slower in the basic solution than in the acidic solutions. The Tafel slopes in 1 M H 2SO 4 were in the range of 0.15 - 0.18 V/decade except for puremore » HfB 2 which showed a Tafel slope of 0.38 V/decade. In 1 M NaOH the Tafel slopes were in the range of 0.12 - 0.27 V/decade. The composition of Hf xZr 1-xB 2 solid solutions with x = 0.2 - 0.8, influenced the exchange current densities, overpotentials and Tafel slopes of the HER. As a result, the EIS data were fitted with a porous film equivalent circuit model in order to better understand the HER behavior. In addition, modeling calculations, using density functional theory approach, were carried out to estimate the density of states and band structure of the boride solid solutions.« less

High precision test of the equivalence principle

NASA Astrophysics Data System (ADS)

Schlamminger, Stephan; Wagner, Todd; Choi, Ki-Young; Gundlach, Jens; Adelberger, Eric

2007-05-01

The equivalence principle is the underlying foundation of General Relativity. Many modern quantum theories of gravity predict violations of the equivalence principle. We are using a rotating torsion balance to search for a new equivalence principle violating, long range interaction. A sensitive torsion balance is mounted on a turntable rotating with constant angular velocity. On the torsion pendulum beryllium and titanium test bodies are installed in a composition dipole configuration. A violation of the equivalence principle would yield to a differential acceleration of the two materials towards a source mass. I will present measurements with a differential acceleration sensitivity of 3x10-15;m/s^2. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.NWS07.B3.5

Evaluation of the water-equivalence of plastic materials in low- and high-energy clinical proton beams

NASA Astrophysics Data System (ADS)

Lourenço, A.; Shipley, D.; Wellock, N.; Thomas, R.; Bouchard, H.; Kacperek, A.; Fracchiolla, F.; Lorentini, S.; Schwarz, M.; MacDougall, N.; Royle, G.; Palmans, H.

2017-05-01

The aim of this work was to evaluate the water-equivalence of new trial plastics designed specifically for light-ion beam dosimetry as well as commercially available plastics in clinical proton beams. The water-equivalence of materials was tested by computing a plastic-to-water conversion factor, {{H}\\text{pl,\\text{w}}} . Trial materials were characterized experimentally in 60 MeV and 226 MeV un-modulated proton beams and the results were compared with Monte Carlo simulations using the FLUKA code. For the high-energy beam, a comparison between the trial plastics and various commercial plastics was also performed using FLUKA and Geant4 Monte Carlo codes. Experimental information was obtained from laterally integrated depth-dose ionization chamber measurements in water, with and without plastic slabs with variable thicknesses in front of the water phantom. Fluence correction factors, {{k}\\text{fl}} , between water and various materials were also derived using the Monte Carlo method. For the 60 MeV proton beam, {{H}\\text{pl,\\text{w}}} and {{k}\\text{fl}} factors were within 1% from unity for all trial plastics. For the 226 MeV proton beam, experimental {{H}\\text{pl,\\text{w}}} values deviated from unity by a maximum of about 1% for the three trial plastics and experimental results showed no advantage regarding which of the plastics was the most equivalent to water. Different magnitudes of corrections were found between Geant4 and FLUKA for the various materials due mainly to the use of different nonelastic nuclear data. Nevertheless, for the 226 MeV proton beam, {{H}\\text{pl,\\text{w}}} correction factors were within 2% from unity for all the materials. Considering the results from the two Monte Carlo codes, PMMA and trial plastic #3 had the smallest {{H}\\text{pl,\\text{w}}} values, where maximum deviations from unity were 1%, however, PMMA range differed by 16% from that of water. Overall, {{k}\\text{fl}} factors were deviating more from unity than {{H}\\text{pl,\\text{w}}} factors and could amount to a few percent for some materials.

Evaluation of the water-equivalence of plastic materials in low- and high-energy clinical proton beams.

PubMed

Lourenço, A; Shipley, D; Wellock, N; Thomas, R; Bouchard, H; Kacperek, A; Fracchiolla, F; Lorentini, S; Schwarz, M; MacDougall, N; Royle, G; Palmans, H

2017-05-21

The aim of this work was to evaluate the water-equivalence of new trial plastics designed specifically for light-ion beam dosimetry as well as commercially available plastics in clinical proton beams. The water-equivalence of materials was tested by computing a plastic-to-water conversion factor, [Formula: see text]. Trial materials were characterized experimentally in 60 MeV and 226 MeV un-modulated proton beams and the results were compared with Monte Carlo simulations using the FLUKA code. For the high-energy beam, a comparison between the trial plastics and various commercial plastics was also performed using FLUKA and Geant4 Monte Carlo codes. Experimental information was obtained from laterally integrated depth-dose ionization chamber measurements in water, with and without plastic slabs with variable thicknesses in front of the water phantom. Fluence correction factors, [Formula: see text], between water and various materials were also derived using the Monte Carlo method. For the 60 MeV proton beam, [Formula: see text] and [Formula: see text] factors were within 1% from unity for all trial plastics. For the 226 MeV proton beam, experimental [Formula: see text] values deviated from unity by a maximum of about 1% for the three trial plastics and experimental results showed no advantage regarding which of the plastics was the most equivalent to water. Different magnitudes of corrections were found between Geant4 and FLUKA for the various materials due mainly to the use of different nonelastic nuclear data. Nevertheless, for the 226 MeV proton beam, [Formula: see text] correction factors were within 2% from unity for all the materials. Considering the results from the two Monte Carlo codes, PMMA and trial plastic #3 had the smallest [Formula: see text] values, where maximum deviations from unity were 1%, however, PMMA range differed by 16% from that of water. Overall, [Formula: see text] factors were deviating more from unity than [Formula: see text] factors and could amount to a few percent for some materials.

Calculation of water equivalent thickness of materials of arbitrary density, elemental composition and thickness in proton beam irradiation

NASA Astrophysics Data System (ADS)

Zhang, Rui; Newhauser, Wayne D.

2009-03-01

In proton therapy, the radiological thickness of a material is commonly expressed in terms of water equivalent thickness (WET) or water equivalent ratio (WER). However, the WET calculations required either iterative numerical methods or approximate methods of unknown accuracy. The objective of this study was to develop a simple deterministic formula to calculate WET values with an accuracy of 1 mm for materials commonly used in proton radiation therapy. Several alternative formulas were derived in which the energy loss was calculated based on the Bragg-Kleeman rule (BK), the Bethe-Bloch equation (BB) or an empirical version of the Bethe-Bloch equation (EBB). Alternative approaches were developed for targets that were 'radiologically thin' or 'thick'. The accuracy of these methods was assessed by comparison to values from an iterative numerical method that utilized evaluated stopping power tables. In addition, we also tested the approximate formula given in the International Atomic Energy Agency's dosimetry code of practice (Technical Report Series No 398, 2000, IAEA, Vienna) and stopping power ratio approximation. The results of these comparisons revealed that most methods were accurate for cases involving thin or low-Z targets. However, only the thick-target formulas provided accurate WET values for targets that were radiologically thick and contained high-Z material.

Does evolution lead to maximizing behavior?

PubMed

Lehmann, Laurent; Alger, Ingela; Weibull, Jörgen

2015-07-01

A long-standing question in biology and economics is whether individual organisms evolve to behave as if they were striving to maximize some goal function. We here formalize this "as if" question in a patch-structured population in which individuals obtain material payoffs from (perhaps very complex multimove) social interactions. These material payoffs determine personal fitness and, ultimately, invasion fitness. We ask whether individuals in uninvadable population states will appear to be maximizing conventional goal functions (with population-structure coefficients exogenous to the individual's behavior), when what is really being maximized is invasion fitness at the genetic level. We reach two broad conclusions. First, no simple and general individual-centered goal function emerges from the analysis. This stems from the fact that invasion fitness is a gene-centered multigenerational measure of evolutionary success. Second, when selection is weak, all multigenerational effects of selection can be summarized in a neutral type-distribution quantifying identity-by-descent between individuals within patches. Individuals then behave as if they were striving to maximize a weighted sum of material payoffs (own and others). At an uninvadable state it is as if individuals would freely choose their actions and play a Nash equilibrium of a game with a goal function that combines self-interest (own material payoff), group interest (group material payoff if everyone does the same), and local rivalry (material payoff differences). © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

On the lorentzian versus Gaussian character of time-domain spin-echo signals from the brain as sampled by means of gradient-echoes: Implications for quantitative transverse relaxation studies.

PubMed

Mulkern, Robert V; Balasubramanian, Mukund; Mitsouras, Dimitrios

2014-07-30

To determine whether Lorentzian or Gaussian intra-voxel frequency distributions are better suited for modeling data acquired with gradient-echo sampling of single spin-echoes for the simultaneous characterization of irreversible and reversible relaxation rates. Clinical studies (e.g., of brain iron deposition) using such acquisition schemes have typically assumed Lorentzian distributions. Theoretical expressions of the time-domain spin-echo signal for intra-voxel Lorentzian and Gaussian distributions were used to fit data from a human brain scanned at both 1.5 Tesla (T) and 3T, resulting in maps of irreversible and reversible relaxation rates for each model. The relative merits of the Lorentzian versus Gaussian model were compared by means of quality of fit considerations. Lorentzian fits were equivalent to Gaussian fits primarily in regions of the brain where irreversible relaxation dominated. In the multiple brain regions where reversible relaxation effects become prominent, however, Gaussian fits were clearly superior. The widespread assumption that a Lorentzian distribution is suitable for quantitative transverse relaxation studies of the brain should be reconsidered, particularly at 3T and higher field strengths as reversible relaxation effects become more prominent. Gaussian distributions offer alternate fits of experimental data that should prove quite useful in general. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

76 FR 454 - Hazardous Materials Transportation: Revisions of Special Permits Procedures

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-05

... the agency to evaluate the applicant's fitness and the safety impact of operations that would be... applicant granted a special permit undergoes a safety fitness evaluation, further assuring the safety of... operations to enable the agency to evaluate the applicant's fitness and the safety impact of operations that...

75 FR 43898 - Hazardous Materials Transportation: Revisions of Special Permits Procedures

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-27

... information about its operations to enable the agency to evaluate the applicant's fitness and the safety... a special permit undergoes a safety fitness evaluation further assuring the safety of transportation... must review an applicant's safety fitness (i.e., previous incidents, citations) to assure that the...

Physical Fitness and Fatness in Adolescents with Intellectual Disabilities

ERIC Educational Resources Information Center

Salaun, Laureline; Berthouze-Aranda, Sophie E.

2012-01-01

Background: This study investigated health-related fitness in adolescents with intellectual disabilities and analysed the various performances in physical fitness tests according to degrees of obesity. Materials and Methods: Eighty-seven French intellectual disabilities adolescents (14.24 [plus or minus] 1.48 years) performed the EUROFIT physical…

Self-selection accounts for inverse association between weight and cardiorespiratory fitness.

PubMed

Williams, Paul T

2008-01-01

Men and women who exercise regularly and who are physically fit tend to be leaner than those who are sedentary and not fit. Although exercise is known to attenuate weight gain and promote weight loss, there may also be a propensity for leaner men and women to choose to exercise vigorously (self-selection). Pre-exercise body weights have been shown to account for all the weight differences between fast and slow walkers, but seem to account for only a portion of the weight differences associated with walking distances. Whether these results apply to maximum exercise performance (i.e., cardiorespiratory fitness) as well as to doses of vigorous exercise (metabolic equivalents >6) remains to be determined. Assess whether the cross-sectional relationships of BMI to cardiorespiratory fitness and vigorous activity are explained by BMI prior to exercising. Cross-sectional study of the relationships between cardiorespiratory fitness (running speed during 10 km foot race) and vigorous physical activity (weekly running distance) to current BMI (BMI(current)) and BMI at the start of running (BMI(starting)) in 44,370 male and 25,252 female participants of the National Runners' Health Study. BMI(starting) accounted entirely for the association between fitness and BMI(current) in both sexes, but only a quarter of the association between vigorous physical activity levels and BMI(current) in men. In women, BMI(starting) accounted for 58% of the association between BMI(current) and vigorous activity levels. Self-selection based on pre-exercise BMI accounts entirely for the association found between fitness and BMI (and possibly a portion of other health outcomes).

Muscular fatigue in response to different modalities of CrossFit sessions

PubMed Central

Maté-Muñoz, José Luis; Lougedo, Juan H.; Barba, Manuel; García-Fernández, Pablo

2017-01-01

Background CrossFit is a new strength and conditioning regimen involving short intense daily workouts called workouts of the day (WOD). This study assesses muscular fatigue levels induced by the three modalities of CrossFit WOD; gymnastics (G), metabolic conditioning (M) and weightlifting (W). Material and methods 34 healthy subjects undertook three WOD (one per week): a G WOD consisting of completing the highest number of sets of 5 pull-ups, 10 push-ups and 15 air squats in 20 min; an M WOD, in which the maximum number of double skipping rope jumps was executed in 8 sets (20 s), resting (10 s) between sets; and finally, a W WOD in which the maximum number of power cleans was executed in 5 min, lifting a load equivalent to 40% of the individual's 1RM. Before and after each WOD, blood lactate concentrations were measured. Also, before, during, and after each WOD, muscular fatigue was assessed in a countermovement jump test (CMJ). Results Significant reductions were produced in the mechanical variables jump height, average power and maximum velocity in response to G; and in jump height, mean and peak power, maximum velocity and maximum force in response to W (P<0.01). However, in M, significant reductions in mechanical variables were observed between pre- and mid session (after sets 2, 4, 6 and 8), but not between pre- and post session. Conclusions Muscular fatigue, reflected by reduced CMJ variables, was produced following the G and W sessions, while recovery of this fatigue was observed at the end of M, likely attributable to rest intervals allowing for the recovery of phosphocreatine stores. Our findings also suggest that the high intensity and volume of exercise in G and W WODs could lead to reduced muscular-tendon stiffness causing a loss of jump ability, related here to a longer isometric phase during the CMJ. PMID:28753624

Measurement of absorbed dose with a bone-equivalent extrapolation chamber.

PubMed

DeBlois, François; Abdel-Rahman, Wamied; Seuntjens, Jan P; Podgorsak, Ervin B

2002-03-01

A hybrid phantom-embedded extrapolation chamber (PEEC) made of Solid Water and bone-equivalent material was used for determining absorbed dose in a bone-equivalent phantom irradiated with clinical radiation beams (cobalt-60 gamma rays; 6 and 18 MV x rays; and 9 and 15 MeV electrons). The dose was determined with the Spencer-Attix cavity theory, using ionization gradient measurements and an indirect determination of the chamber air-mass through measurements of chamber capacitance. The collected charge was corrected for ionic recombination and diffusion in the chamber air volume following the standard two-voltage technique. Due to the hybrid chamber design, correction factors accounting for scatter deficit and electrode composition were determined and applied in the dose equation to obtain absorbed dose in bone for the equivalent homogeneous bone phantom. Correction factors for graphite electrodes were calculated with Monte Carlo techniques and the calculated results were verified through relative air cavity dose measurements for three different polarizing electrode materials: graphite, steel, and brass in conjunction with a graphite collecting electrode. Scatter deficit, due mainly to loss of lateral scatter in the hybrid chamber, reduces the dose to the air cavity in the hybrid PEEC in comparison with full bone PEEC by 0.7% to approximately 2% depending on beam quality and energy. In megavoltage photon and electron beams, graphite electrodes do not affect the dose measurement in the Solid Water PEEC but decrease the cavity dose by up to 5% in the bone-equivalent PEEC even for very thin graphite electrodes (<0.0025 cm). In conjunction with appropriate correction factors determined with Monte Carlo techniques, the uncalibrated hybrid PEEC can be used for measuring absorbed dose in bone material to within 2% for high-energy photon and electron beams.

Dose estimation and dating of pottery from Turkey

NASA Astrophysics Data System (ADS)

Altay Atlıhan, M.; Şahiner, Eren; Soykal Alanyalı, Feriştah

2012-06-01

The luminescence method is a widely used technique for environmental dosimetry and dating archaeological, geological materials. In this study, equivalent dose (ED) and annual dose rate (AD) of an archaeological sample were measured. The age of the material was calculated by means of equivalent dose divided by the annual dose rate. The archaeological sample was taken from Antalya, Turkey. Samples were prepared by the fine grain technique and equivalent dose was found using multiple-aliquot-additive-dose (MAAD) and single aliquot regeneration (SAR) techniques. Also the short shine normalization-MAAD and long shine normalization-MAAD were applied and the results of the methods were compared with each other. The optimal preheat temperature was found to be 200 °C for 10 min. The annual doses of concentrations of the major radioactive isotopes were determined using a high-purity germanium detector and a low-level alpha counter. The age of the sample was found to be 510±40 years.

Assessment of boric acid and borax using the IEHR evaluative process for assessing human developmental and reproductive toxicity of agents

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

Moore, J.A.

This document presents an evaluation of the reproductive and developmental effects of boric acid, H3BO3 (CAS Registry No. 10043-35-3) and disodium tetraborate decahydrate or borax, Na2B4O2O(CAS Registry No. 1303-96-4). The element, boron, does not exist naturally. In dilute aqueous solution and at physiological pH (7.4), the predominant species in undissociated boric acid (greater than 98%), irrespective of whether the initial material was boric acid of borax. Therefore, it is both useful and correct to compare exposures and dosages to boric acid and borax in terms of `boron equivalents`, since both materials form equivalent species in dilute aqueous solution with similarmore » systemic effects. In order to be clear in this document, the term `boron` will refer to `boron equivalents` or percent boron in boric acid and borax.« less

Planning for Coupling Effects in Bitoric Mixed Astigmatism Ablative Treatments.

PubMed

Alpins, Noel; Ong, James K Y; Stamatelatos, George

2017-08-01

To demonstrate how to determine the historical coupling adjustments of bitoric mixed astigmatism ablative treatments and how to use these historical coupling adjustments to adjust future bitoric treatments. The individual coupling adjustments of the myopic and hyperopic cylindrical components of a bitoric treatment were derived empirically from a retrospective study where the theoretical combined treatment effect on spherical equivalent was compared to the actual change in refractive spherical equivalent. The coupling adjustments that provided the best fit in both mean and standard deviation were determined to be the historical coupling adjustments. Theoretical treatments that incorporated the historical coupling adjustments were then calculated. The actual distribution of postoperative spherical equivalent errors was compared to the theoretically adjusted distribution. The study group comprised 242 eyes and included 118 virgin right eyes and 124 virgin left eyes of 155 individuals. For the laser used, the myopic coupling adjustment was -0.02 and the hyperopic coupling adjustment was 0.30, as derived by global nonlinear optimization. This implies that almost no adjustment of the myopic component of the bitoric treatment is necessary, but that the hyperopic component of the bitoric treatment generates a large amount of unintended spherical shift. The theoretically adjusted treatments targeted zero mean spherical equivalent error, as intended, and the distribution of the theoretical spherical equivalent errors had the same spread as the distribution of actual postoperative spherical equivalent errors. Bitoric mixed astigmatism ablative treatments may display non-trivial coupling effects. Historical coupling adjustments should be taken into consideration when planning mixed astigmatism treatments to improve surgical outcomes. [J Refract Surg. 2017;33(8):545-551.]. Copyright 2017, SLACK Incorporated.

Agreement Between VO2peak Predicted From PACER and One-Mile Run Time-Equated Laps.

PubMed

Saint-Maurice, Pedro F; Anderson, Katelin; Bai, Yang; Welk, Gregory J

2016-12-01

This study examined the agreement between estimated peak oxygen consumption (VO 2peak ) obtained from the Progressive Aerobic Cardiovascular Endurance Run (PACER) fitness test and equated PACER laps derived from One-Mile Run time (MR). A sample of 680 participants (324 boys and 356 girls) in Grades 7 through 12 completed both the PACER and the MR assessments. MR time was converted to PACER laps (PACER-MEQ) using previously developed conversion algorithms. Agreement between PACER and PACER-MEQ VO 2peak was examined using Pearson correlations, mean absolute percent error (MAPE), and equivalence testing procedures. Classification agreement based on health-related standards was examined using sensitivity, specificity, and Kappa statistics. Overall agreement between estimated VO 2peak obtained from the PACER and PACER-MEQ was high in boys, r(324) = .79, R 2  = .63, and moderate in girls, r(356) = .57, R 2  = .33. The MAPE for estimates obtained from PACER-MEQ was 10.3% and estimates were deemed equivalent to the PACER (43.1 ± 6.9 mL/kg/min vs. 44.6 ± 0.3 mL/kg/min). Classification agreement as illustrated by sensitivity and specificity ranged from 20.4% to 90.2% and was higher for classifications in the Healthy Fitness Zone (HFZ). Kappa statistics ranged from .14 to .51 and were also higher for the HFZ. Equated PACER laps can be used to obtain equivalent estimates of PACER VO 2peak in groups of adolescents, but some disparities can be found when students' scores are classified into the Needs Improvement Zone.

Temperature Dependence of Molecular Line Strengths and Fei 1565 nm Zeeman Splitting in a Sunspot

NASA Astrophysics Data System (ADS)

Penn, M. J.; Walton, S.; Chapman, G.; Ceja, J.; Plick, W.

2003-03-01

Spectroscopic observations at 1565 nm were made in the eastern half of the main umbra of NOAA 9885 on 1 April 2002 using the National Solar Observatory McMath-Pierce Telescope at Kitt Peak with a tip-tilt image stabilization system and the California State University Northridge-National Solar Observatory infrared camera. The line depth of the OH blend at 1565.1 nm varies with the observed continuum temperature; the variation fits previous observations except that the continuum temperature is lower by 600 K. The equivalent width of the OH absorption line at 1565.2 nm shows a temperature dependence similar to previously published umbral molecular observations at 640 nm. A simple model of expected OH abundance based upon an ionization analogy to molecular dissociation is produced and agrees well with the temperature variation of the line equivalent width. A CN absorption line at 1564.6 nm shows a very different temperature dependence, likely due to complicated formation and destruction processes. Nonetheless a numerical fit of the temperature variation of the CN equivalent width is presented. Finally a comparison of the Zeeman splitting of the Fei 1564.8 nm line with the sunspot temperature derived from the continuum intensity shows an umbra somewhat cooler for a given magnetic field strength than previous comparisons using this infrared 1564.8 nm line, but consistent with these previous infrared measurements the umbra is hotter for a given magnetic field strength than magnetic and temperature measurements at 630.2 nm would suggest. Differences between the 630.2 nm and 1564.8 nm umbral temperature and magnetic field relations are explained with the different heights of formation of the lines and continua at these wavelengths.

Physical Fitness and Hypertension in a Population at Risk for Cardiovascular Disease: The Henry Ford ExercIse Testing (FIT) Project

PubMed Central

Juraschek, Stephen P.; Blaha, Michael J.; Whelton, Seamus P.; Blumenthal, Roger; Jones, Steven R.; Keteyian, Steven J.; Schairer, John; Brawner, Clinton A.; Al‐Mallah, Mouaz H.

2014-01-01

Background Increased physical fitness is protective against cardiovascular disease. We hypothesized that increased fitness would be inversely associated with hypertension. Methods and Results We examined the association of fitness with prevalent and incident hypertension in 57 284 participants from The Henry Ford ExercIse Testing (FIT) Project (1991–2009). Fitness was measured during a clinician‐referred treadmill stress test. Incident hypertension was defined as a new diagnosis of hypertension on 3 separate consecutive encounters derived from electronic medical records or administrative claims files. Analyses were performed with logistic regression or Cox proportional hazards models and were adjusted for hypertension risk factors. The mean age overall was 53 years, with 49% women and 29% black. Mean peak metabolic equivalents (METs) achieved was 9.2 (SD, 3.0). Fitness was inversely associated with prevalent hypertension even after adjustment (≥12 METs versus <6 METs; OR: 0.73; 95% CI: 0.67, 0.80). During a median follow‐up period of 4.4 years (interquartile range: 2.2 to 7.7 years), there were 8053 new cases of hypertension (36.4% of 22 109 participants without baseline hypertension). The unadjusted 5‐year cumulative incidences across categories of METs (<6, 6 to 9, 10 to 11, and ≥12) were 49%, 41%, 30%, and 21%. After adjustment, participants achieving ≥12 METs had a 20% lower risk of incident hypertension compared to participants achieving <6 METs (HR: 0.80; 95% CI: 0.72, 0.89). This relationship was preserved across strata of age, sex, race, obesity, resting blood pressure, and diabetes. Conclusions Higher fitness is associated with a lower probability of prevalent and incident hypertension independent of baseline risk factors. PMID:25520327

Body mass index, exercise capacity, and mortality risk in male veterans with hypertension.

PubMed

Faselis, Charles; Doumas, Michael; Panagiotakos, Demosthenes; Kheirbek, Raya; Korshak, Lauren; Manolis, Athanasios; Pittaras, Andreas; Tsioufis, Costas; Papademetriou, Vasilios; Fletcher, Ross; Kokkinos, Peter

2012-04-01

Overweight and obesity are associated with increased risk of chronic diseases and mortality. Exercise capacity is inversely associated with mortality risk. However, little is known on the interaction between fitness, fatness, and mortality risk in hypertensive individuals. Thus, we assessed the interaction between exercise capacity, fatness, and all-cause mortality in hypertensive males. A graded exercise test was performed in 4,183 hypertensive veterans (mean age ± s.d.; 63.3 ± 10.5 years) at the Veterans Affairs Medical Center, Washington, DC. We defined three body weight categories based on body mass index (BMI): normal weight (BMI <25); overweight (BMI 25-29.9); and obese (BMI ≥30); and three fitness categories based on peak metabolic equivalents (METs) achieved: low-fit (≤5 METs); moderate-fit (5.1-7.5 MET); and high-fit (>7.5 METs). During a median follow-up period of 7.2 years, there were 1,000 deaths. The association between exercise capacity and mortality risk was strong, inverse, and graded. For each 1-MET increase in exercise capacity the adjusted risk was 20% for normal weight, 12% for overweight, and 25% for obese (P < 0.001). When compared to normal weight but unfit individuals, mortality risks were 60% lower in the overweight/high-fit and 78% lower in the obese/high-fit individuals (P < 0.001). Increased exercise capacity is associated with lower mortality risk in hypertensive males regardless of BMI. The risk for overweight and obese but fit individuals was significantly lower when compared to normal weight but unfit. These findings suggest that in older hypertensive men, it may be healthier to be fit regardless of standard BMI category than unfit and normal weight.

Ab initio potential energy and dipole moment surfaces of the F(-)(H2O) complex.

PubMed

Kamarchik, Eugene; Toffoli, Daniele; Christiansen, Ove; Bowman, Joel M

2014-02-05

We present full-dimensional, ab initio potential energy and dipole moment surfaces for the F(-)(H2O) complex. The potential surface is a permutationally invariant fit to 16,114 coupled-cluster single double (triple)/aVTZ energies, while the dipole surface is a covariant fit to 11,395 CCSD(T)/aVTZ dipole moments. Vibrational self-consistent field/vibrational configuration interaction (VSCF/VCI) calculations of energies and the IR-spectrum are presented both for F(-)(H2O) and for the deuterated analog, F(-)(D2O). A one-dimensional calculation of the splitting of the ground state, due to equivalent double-well global minima, is also reported. Copyright © 2013 Elsevier B.V. All rights reserved.

TAKING THE LONG VIEW TOWARDS THE LONG WAR. Equipping General Purpose Force Leaders with Soft Power Tools for Irregular Warfare

DTIC Science & Technology

2009-02-12

equivalent to usual printing or typescript . Can read either representations of familiar formulaic verbal exchanges or simple language containing only...read simple, authentic written material in a form equivalent to usual printing or typescript on subjects within a familiar context. Able to read with

Identifying, Tracking, and Prioritizing Parts Unavailability

DTIC Science & Technology

2013-03-01

of RFM with MRP Equivalents in Parentheses ................ 13 Figure 2. Flow Chart of Repair Process...by the Air Force is the Reparability Forecast Model (RFM). The RFM operates similar to a Material Requirements Planning ( MRP ) system, where it...Outputs of RFM with MRP Equivalents in Parentheses (Gaudette et al, 2002: 7) The Reparability Forecast Model does not determine stock levels or

Advanced Life Support Equivalent System Mass Guidelines Document

NASA Technical Reports Server (NTRS)

Levri, Julie; Fisher, John W.; Jones, Harry W.; Drysdale, Alan E.; Ewert, Michael K.; Hanford, Anthony J.; Hogan, John A.; Joshi, Jitendri, A.; Vaccari, David A.

2003-01-01

This document is a viewgraph presentation which provides guidelines for performing an Equivalent System Mass (ESM) evaluation for trade study purposes. The document: 1) Defines ESM; 2) Explains how to calculate ESM; 3) Discusses interpretation of ESM results. The document is designed to provide detailed instructive material for researchers who are performing ESM evaluations for the first time.

76 FR 53117 - Virginia Polytechnic Institute, et al.; Notice of Decision on Applications for Duty-Free Entry of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-25

... received. Decision: Approved. We know of no instruments of equivalent scientific value to the foreign... received. Decision: Approved. We know of no instruments of equivalent scientific value to the foreign... magnetic fields, which requires a special selection of non-magnetic materials the instrument has to be...

EPR hyperfine structure of the Mo-related defect in CdWO4

NASA Astrophysics Data System (ADS)

Elsts, E.; Rogulis, U.

2005-01-01

The hyperfine structure (hf) of the electron paramagnetic resonance (EPR) spectrum of Mo-related impurity defects in CdWO4 crystals observed previously (U. Rogulis, Radiat. Meas. 29, 287 (1998) [1]) is reconsidered taking into account interactions with two different groups of neighbouring Cd nuclei. The best fit calculated EPR spectrum to the experimental is obtained considering 2 groups of 3 and 2 equivalent Cd nuclei, respectively.

Measurement equivalence across gender and education in the WHOQOL-BREF for community-dwelling elderly Taiwanese.

PubMed

Lin, Chung-Ying; Li, Yueh-Ping; Lin, Sang-I; Chen, Ching-Huey

2016-08-01

The WHOQOL-BREF, a generic quality of life (QoL) instrument, has been widely used clinically and for research on older populations. However, its measurement equivalence/invariance (ME/I) has not been well examined for the elderly (≥ 65 years) across some different demographics. The data were derived from a cross-sectional study with a convenience sampling design in Taiwan. We enrolled 244 elderly participants: men = 143 (58.6%); educational level ≤ primary school = 121 (49.6%). The ME/I was examined using multiple group confirmatory factor analysis (MGCFA) across gender and educational level. The fit indices were satisfactory for the configural models of gender and educational level (standardized root mean square residual [SRMR] = 0.0742 and 0.0770; root mean square error of approximation [RMSEA] = 0.0655 and 0.0686; comparative fit index [CFI] = 0.953). In addition, MGCFAs showed that ME/I was supported across gender (ΔSRMR = 0.001 to 0.019; ΔRMSEA = -0.003 to 0.001; ΔCFI = -0.003 to 0.000) and educational level (ΔSRMR = 0.002 to 0.006; ΔRMSEA = -0.002 to 0.004; ΔCFI = -0.007 to 0.000). The WHOQOL-BREF Taiwan version is appropriate for combined use and for comparisons in older people across gender and different educational levels.

Theory of time-averaged neutral dynamics with environmental stochasticity

NASA Astrophysics Data System (ADS)

Danino, Matan; Shnerb, Nadav M.

2018-04-01

Competition is the main driver of population dynamics, which shapes the genetic composition of populations and the assembly of ecological communities. Neutral models assume that all the individuals are equivalent and that the dynamics is governed by demographic (shot) noise, with a steady state species abundance distribution (SAD) that reflects a mutation-extinction equilibrium. Recently, many empirical and theoretical studies emphasized the importance of environmental variations that affect coherently the relative fitness of entire populations. Here we consider two generic time-averaged neutral models; in both the relative fitness of each species fluctuates independently in time but its mean is zero. The first (model A) describes a system with local competition and linear fitness dependence of the birth-death rates, while in the second (model B) the competition is global and the fitness dependence is nonlinear. Due to this nonlinearity, model B admits a noise-induced stabilization mechanism that facilitates the invasion of new mutants. A self-consistent mean-field approach is used to reduce the multispecies problem to two-species dynamics, and the large-N asymptotics of the emerging set of Fokker-Planck equations is presented and solved. Our analytic expressions are shown to fit the SADs obtained from extensive Monte Carlo simulations and from numerical solutions of the corresponding master equations.

Fundamental movement skills and physical fitness as predictors of physical activity: A 6-year follow-up study.

PubMed

Jaakkola, T; Yli-Piipari, S; Huotari, P; Watt, A; Liukkonen, J

2016-01-01

The purpose of this study was to examine the extent to which fundamental movement skills and physical fitness scores assessed in early adolescence predict self-reported physical activity assessed 6 years later. The sample comprised 333 (200 girls, 133 boys; M age = 12.41) students. The effects of previous physical activity, sex, and body mass index (BMI) were controlled in the main analyses. Adolescents' fundamental movement skills, physical fitness, self-report physical activity, and BMI were collected at baseline, and their self-report energy expenditure (metabolic equivalents: METs) and intensity of physical activity were collected using the International Physical Activity Questionnaire 6 years later. Results showed that fundamental movement skills predicted METs, light, moderate, and vigorous intensity physical activity levels, whereas fitness predicted METs, moderate, and vigorous physical activity levels. Hierarchical regression analyses also showed that after controlling for previous levels of physical activity, sex, and BMI, the size of the effect of fundamental movement skills and physical fitness on energy expenditure and physical activity intensity was moderate (R(2) change between 0.06 and 0.15), with the effect being stronger for high intensity physical activity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Preliminary analysis of accelerated space flight ionizing radiation testing

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Stock, L. V.; Carter, D. J.; Chang, C. K.

1982-01-01

A preliminary analysis shows that radiation dose equivalent to 30 years in the geosynchronous environment can be accumulated in a typical composite material exposed to space for 2 years or less onboard a spacecraft orbiting from perigee of 300 km out to the peak of the inner electron belt (approximately 2750 km). Future work to determine spacecraft orbits better tailored to materials accelerated testing is indicated. It is predicted that a range of 10 to the 9th power to 10 to the 10th power rads would be accumulated in 3-6 mil thick epoxy/graphite exposed by a test spacecraft orbiting in the inner electron belt. This dose is equivalent to the accumulated dose that this material would be expected to have after 30 years in a geosynchronous orbit. It is anticipated that material specimens would be brought back to Earth after 2 years in the radiation environment so that space radiation effects on materials could be analyzed by laboratory methods.

Optimum Material Composition for Minimizing the Stress Intensity Factor of Edge Crack in Thick-Walled FGM Circular Pipes Under Thermomechanical Loading

NASA Astrophysics Data System (ADS)

Sekine, Hideki; Yoshida, Kimiaki

This paper deals with the optimization problem of material composition for minimizing the stress intensity factor of radial edge crack in thick-walled functionally graded material (FGM) circular pipes under steady-state thermomechanical loading. Homogenizing the FGM circular pipes by simulating the inhomogeneity of thermal conductivity by a distribution of equivalent eigentemperature gradient and the inhomogeneity of Young's modulus and Poisson's ratio by a distribution of equivalent eigenstrain, we present an approximation method to obtain the stress intensity factor of radial edge crack in the FGM circular pipes. The optimum material composition for minimizing the stress intensity factor of radial edge crack is determined using a nonlinear mathematical programming method. Numerical results obtained for a thick-walled TiC/Al2O3 FGM circular pipe reveal that it is possible to decrease remarkably the stress intensity factor of radial edge crack by setting the optimum material composition profile.

Gamma index evaluation of IMRT technique using gafchromic film EBT3 for homogeneous and inhomogeneous material

NASA Astrophysics Data System (ADS)

Nisauf, T. A.; Wibowo, W. E.; Pawiro, S. A.

2017-07-01

This study was done to evaluate the gamma index for registering between the planar of dose planning and the measurement of EBT film. The treatment plan was simulated for 5 patients using Fan Beam Computerized Tomography (FBCT) modality, Philips Pinnacle planning system, 6 MV photon energy, 50 segments IMRT technique, and calculation grid resolution (CGR) of 0.2 cm. Gamma Index (GI) evaluation was done with criteria of dose difference (DD) of 2 %, dose to agreement (DTA) of 2 mm and dose difference (DD) of 5 % DTA of 3 mm, SAD 100 cm, depth of 5 cm and 10 cm of the phantom. The result shows that GI for homogeneous material is greater than for inhomogeneous material with discrepancy to previous work is about 1.98 % for homogeneous material (depth 5 cm) and 2.05 % (depth 10 cm) while it was found of 2.98 % for inhomogeneous material (equivalent depth 5 cm) and 4.59 % (equivalent depth 10 cm).

The Role of ESA TEC-QTE in the ISS Safety Process

NASA Astrophysics Data System (ADS)

Orlandi, M.; Rohr, T.; Stienstra, M. H.; Semprimoschnig, C.

2013-09-01

On the 17th of July 2000, the Materials and Processes Reciprocal Agreement was signed between NASA and ESA to define the process for selection and certification of materials used in the Space Shuttle and the International Space Station. Consecutively, on the 20th of June 2003 this agreement was extended to the Automated Transport Vehicle (ATV). It is therefore the responsibility of ESA TEC-QTE, the Materials Space Evaluation and Radiation Effects section, part of the Product Assurance and Safety Department, to ensure that all materials, parts and processes of each of the ISS payloads not only function as required but also do not pose a risk to the safety of the crew members. In this context, TEC-QTE provides qualified expertise to support the ESA Flight Safety Review and assesses safety aspects related to manned projects (materials properties, fluid system compatibility, fungus resistance). This is supported by the Materials Space Evaluation and Radiation Effects section's Materials and Electrical Components laboratory having at its disposition a range of facilities designed to perform environmental effects testing of which off-gassing tests according to ECSS-Q-ST-70-29C (equivalent to NASA STD 6001 test 7) and outgassing tests according to ECSS-Q-ST-70-02C (equivalent to ASTM-E-595). The ESA facility to perform flammability tests according to ECSS-Q-ST-70-21A (equivalent to NASA STD 6001 test1) was moved to Astrium Bremen.TEC-QTE is in charge of reviewing and approving, via RFA or MUA , all materials that do not meet safety requirements as well as COTS or CAM (black boxes) equipment.The safety process ends with the issue of the Materials Certification of the reviewed payload hardware that shows compliance with the relevant materials and processes requirements and standards.In addition to the safety related activities for the ISS, specialised TEC-QTE personnel provide measurements of the air quality inside the ATV and assess whether the toxicity index is within requirements.

Earthquake simulator tests and associated study of an 1/6-scale nine-story RC model

NASA Astrophysics Data System (ADS)

Sun, Jingjiang; Wang, Tao; Qi, Hu

2007-09-01

Earthquake simulator tests of a 1/6-scale nine-story reinforced concrete frame-wall model are described in the paper. The test results and associated numerical simulation are summarized and discussed. Based on the test data, a relationship between maximum inter-story drift and damage state is established. Equations of variation of structural characteristics (natural frequency and equivalent stiffness) with overall drifts are derived by data fitting, which can be used to estimate structural damage state if structural characteristics can be measured. A comparison of the analytical and experimental results show that both the commonly used equivalent beam and fiber element models can simulate the nonlinear seismic response of structures very well. Finally, conclusions associated with seismic design and damage evaluation of RC structures are presented.

The Strengths and Difficulties Questionnaire (SDQ): Factor Structure and Gender Equivalence in Norwegian Adolescents.

PubMed

Bøe, Tormod; Hysing, Mari; Skogen, Jens Christoffer; Breivik, Kyrre

2016-01-01

Although frequently used with older adolescents, few studies of the factor structure, internal consistency and gender equivalence of the SDQ exists for this age group, with inconsistent findings. In the present study, confirmatory factor analysis (CFA) was used to evaluate the five-factor structure of the SDQ in a population sample of 10,254 16-18 year-olds from the youth@hordaland study. Measurement invariance across gender was assessed using multigroup CFA. A modestly modified five-factor solution fitted the data acceptably, accounting for one cross loading and some local dependencies. Importantly, partial measurement non-invariance was identified, with differential item functioning in eight items, and higher correlations between emotional and conduct problems for boys compared to girls. Implications for use clinically and in research are discussed.

Evaluation of 3D printing materials for fabrication of a novel multi-functional 3D thyroid phantom for medical dosimetry and image quality

NASA Astrophysics Data System (ADS)

Alssabbagh, Moayyad; Tajuddin, Abd Aziz; Abdulmanap, Mahayuddin; Zainon, Rafidah

2017-06-01

Recently, the three-dimensional printer has started to be utilized strongly in medical industries. In the human body, many parts or organs can be printed from 3D images to meet accurate organ geometries. In this study, five common 3D printing materials were evaluated in terms of their elementary composition and the mass attenuation coefficients. The online version of XCOM photon cross-section database was used to obtain the attenuation values of each material. The results were compared with the attenuation values of the thyroid listed in the International Commission on Radiation Units and Measurements - ICRU 44. Two original thyroid models (hollow-inside and solid-inside) were designed from scratch to be used in nuclear medicine, diagnostic radiology and radiotherapy for dosimetry and image quality purposes. Both designs have three holes for installation of radiation dosimeters. The hollow-inside model has more two holes in the top for injection the radioactive materials. The attenuation properties of the Polylactic Acid (PLA) material showed a very good match with the thyroid tissue, which it was selected to 3D print the phantom using open source RepRap, Prusa i3 3D printer. The scintigraphy images show that the phantom simulates a real healthy thyroid gland and thus it can be used for image quality purposes. The measured CT numbers of the PA material after the 3D printing show a close match with the human thyroid CT numbers. Furthermore, the phantom shows a good accommodation of the TLD dosimeters inside the holes. The 3D fabricated thyroid phantom simulates the real shape of the human thyroid gland with a changeable geometrical shape-size feature to fit different age groups. By using 3D printing technology, the time required to fabricate the 3D phantom was considerably shortened compared to the longer conventional methods, where it took only 30 min to print out the model. The 3D printing material used in this study is commercially available and cost-effective compared to current commercial tissue-equivalent materials.

SU-E-T-424: Feasibility of 3D Printed Radiological Equivalent Customizable Tissue Like Materials

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

Johnson, D; Ferreira, C; Ahmad, S

Purpose: To investigate the feasibility of 3D printing CT# specific radiological equivalent tissue like materials. Methods: A desktop 3D printer was utilized to create a series of 3 cm x 3 cm x 2 cm PLA plastic blocks of varying fill densities. The fill pattern was selected to be hexagonal (Figure 1). A series of blocks was filled with paraffin and compared to a series filled with air. The blocks were evaluated with a “GE Lightspeed” 16 slice CT scanner and average CT# of the centers of the materials was determined. The attenuation properties of the subsequent blocks were alsomore » evaluated through their isocentric irradiation via “TrueBeam” accelerator under six beam energies. Blocks were placed upon plastic-water slabs of 4 cm in thickness assuring electronic equilibrium and data was collected via Sun Nuclear “Edge” diode detector. Relative changes in dose were compared with those predicted by Varian “Eclipse” TPS. Results: The CT# of 3D printed blocks was found to be a controllable variable. The fill material was able to narrow the range of variability in each sample. The attenuation of the block tracked with the density of the total fill structure. Assigned CT values in the TPS were seen to fall within an expected range predicted by the CT scans of the 3D printed blocks. Conclusion: We have demonstrated that it is possible to 3D print materials of varying tissue equivalencies, and that these materials have radiological properties that are customizable and predictable.« less

Ignition Delay of Combustible Materials in Normoxic Equivalent Environments

NASA Technical Reports Server (NTRS)

McAllister, Sara; Fernandez-Pello, Carlos; Ruff, Gary; Urban, David

2009-01-01

Material flammability is an important factor in determining the pressure and composition (fraction of oxygen and nitrogen) of the atmosphere in the habitable volume of exploration vehicles and habitats. The method chosen in this work to quantify the flammability of a material is by its ease of ignition. The ignition delay time was defined as the time it takes a combustible material to ignite after it has been exposed to an external heat flux. Previous work in the Forced Ignition and Spread Test (FIST) apparatus has shown that the ignition delay in the currently proposed space exploration atmosphere (approximately 58.6 kPa and32% oxygen concentration) is reduced by 27% compared to the standard atmosphere used in the Space Shuttle and Space Station. In order to determine whether there is a safer environment in terms of material flammability, a series of piloted ignition delay tests using polymethylmethacrylate (PMMA) was conducted in the FIST apparatus to extend the work over a range of possible exploration atmospheres. The exploration atmospheres considered were the normoxic equivalents, i.e. reduced pressure conditions with a constant partial pressure of oxygen. The ignition delay time was seen to decrease as the pressure was reduced along the normoxic curve. The minimum ignition delay observed in the normoxic equivalent environments was nearly 30% lower than in standard atmospheric conditions. The ignition delay in the proposed exploration atmosphere is only slightly larger than this minimum. Interms of material flammability, normoxic environments with a higher pressure relative to the proposed pressure would be desired.

Health and Fitness Through Physical Activity.

ERIC Educational Resources Information Center

Pollock, Michael L.; And Others

A synthesis of research findings in exercise and physical fitness is presented to provide the general public with insights into establishing an individualized exercise program. The material is divided into seven subtopics: (1) a general overview of the need for exercise and fitness and how it is an integral part of preventive medicine programs;…

49 CFR 179.102-3 - Materials poisonous by inhalation.

Code of Federal Regulations, 2014 CFR

2014-10-01

... top fitting protection system and nozzle capable of sustaining, without failure, a rollover accident... geometric center of the loaded tank car as a transverse vector. Failure is deemed to occur when the deformed... any top fitting in the case of an accident where any top fitting would be sheared off. The tank nozzle...

49 CFR 179.102-3 - Materials poisonous by inhalation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... top fitting protection system and nozzle capable of sustaining, without failure, a rollover accident... geometric center of the loaded tank car as a transverse vector. Failure is deemed to occur when the deformed... any top fitting in the case of an accident where any top fitting would be sheared off. The tank nozzle...

49 CFR 179.102-3 - Materials poisonous by inhalation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... top fitting protection system and nozzle capable of sustaining, without failure, a rollover accident... geometric center of the loaded tank car as a transverse vector. Failure is deemed to occur when the deformed... any top fitting in the case of an accident where any top fitting would be sheared off. The tank nozzle...

49 CFR 179.102-3 - Materials poisonous by inhalation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... top fitting protection system and nozzle capable of sustaining, without failure, a rollover accident... geometric center of the loaded tank car as a transverse vector. Failure is deemed to occur when the deformed... any top fitting in the case of an accident where any top fitting would be sheared off. The tank nozzle...

Evaluation of marginal fit of two all-ceramic copings with two finish lines

PubMed Central

Subasi, Gulce; Ozturk, Nilgun; Inan, Ozgur; Bozogullari, Nalan

2012-01-01

Objectives: This in-vitro study investigated the marginal fit of two all-ceramic copings with 2 finish line designs. Methods: Forty machined stainless steel molar die models with two different margin designs (chamfer and rounded shoulder) were prepared. A total of 40 standardized copings were fabricated and divided into 4 groups (n=10 for each finish line-coping material). Coping materials tested were IPS e.max Press and Zirkonzahn; luting agent was Variolink II. Marginal fit was evaluated after cementation with a stereomicroscope (Leica MZ16). Two-way analysis of variance and Tukey-HSD test were performed to assess the influence of each finish line design and ceramic type on the marginal fit of 2 all-ceramic copings (α =.05). Results: Two-way analysis of variance revealed no statistically significant differences for marginal fit relative to finish lines (P=.362) and ceramic types (P=.065). Conclusion: Within the limitations of this study, both types of all-ceramic copings demonstrated that the mean marginal fit was considered acceptable for clinical application (⩽120 μm). PMID:22509119

Applicability of the lattice Boltzmann method to determine the ohmic resistance in equivalent resistor connections

NASA Astrophysics Data System (ADS)

Espinoza-Andaluz, Mayken; Barzola, Julio; Guarochico-Moreira, Víctor H.; Andersson, Martin

2017-12-01

Knowing the ohmic resistance in the materials allow to know in advance its electrical behavior when a potential difference is applied, and therefore the prediction of the electrical performance can be achieved in a most certain manner. Although the Lattice Boltzmann method (LBM) has been applied to solve several physical phenomena in complex geometries, it has only been used to describe the fluid phase, but applicability studies of LBM on the solid-electric-conducting material have not been carried out yet. The purpose of this paper is to demonstrate the accuracy of calculating the equivalent resistor connections using LBM. Several series and parallel resistor connections are effected. All the computations are carried out with 3D models, and the domain materials are designed by the authors.

Ceramics for Molten Materials Transfer

NASA Technical Reports Server (NTRS)

Standish, Evan; Stefanescu, Doru M.; Curreri, Peter A.

2009-01-01

The paper reviews the main issues associated with molten materials transfer and handling on the lunar surface during the operation of a hig h temperature electrowinning cell used to produce oxygen, with molten iron and silicon as byproducts. A combination of existing technolog ies and purposely designed technologies show promise for lunar exploi tation. An important limitation that requires extensive investigation is the performance of refractory currently used for the purpose of m olten metal containment and transfer in the lunar environment associa ted with electrolytic cells. The principles of a laboratory scale uni t at a scale equivalent to the production of 1 metric ton of oxygen p er year are introduced. This implies a mass of molten materials to be transferred consistent with the equivalent of 1kg regolithlhr proces sed.

A History of the Chemical Innovations in Silver-Halide Materials for Color PhotographyII. Color-Forming Development, Part 5. Coupler Innovations after the 1970's—Two-Equivalent Coupler and DIR Coupler

NASA Astrophysics Data System (ADS)

Oishi, Yasushi

After the 1970's on, several manufacturers including Fuji Film, Konica and Agfa-Gevaert participated in innovating color photographic materials by adding their own coupler chemistry to the technological architecture built by Kodak before then. One area of their major advances was development of the couplers having a coupling-off organic group. One of their functional forms was two-equivalent coupler which made the dye-forming process efficient and made the photosensitive layers slim. And another was DIR coupler which improved dramatically the image quality of color negative materials. In this paper a historical overview of these innovations is constructed from the technical documents, mainly patents.

Electron Density Calibration for Radiotherapy Treatment Planning

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

Herrera-Martinez, F.; Rodriguez-Villafuerte, M.; Martinez-Davalos, A.

2006-09-08

Computed tomography (CT) images are used as basic input data for most modern radiosurgery treatment planning systems (TPS). CT data not only provide anatomic information to delineate target volumes, but also allow the introduction of corrections for tissue inhomogeneities into dose calculations during the treatment planning procedure. These corrections involve the determination of a relationship between tissue electron density ({rho}e) and their corresponding Hounsfield Units (HU). In this work, an elemental analysis of different commercial tissue equivalent materials using Scanning Electron Microscopy was carried out to characterize their chemical composition. The tissue equivalent materials were chosen to ensure a largemore » range of {rho}e to be included in the CT scanner calibration. A phantom was designed and constructed with these materials to simulate the size of a human head.« less

Linear Combination Fitting (LCF)-XANES analysis of As speciation in selected mine-impacted materials

EPA Pesticide Factsheets

This table provides sample identification labels and classification of sample type (tailings, calcinated, grey slime). For each sample, total arsenic and iron concentrations determined by acid digestion and ICP analysis are provided along with arsenic in-vitro bioaccessibility (As IVBA) values to estimate arsenic risk. Lastly, the table provides linear combination fitting results from synchrotron XANES analysis showing the distribution of arsenic speciation phases present in each sample along with fitting error (R-factor).This dataset is associated with the following publication:Ollson, C., E. Smith, K. Scheckel, A. Betts, and A. Juhasz. Assessment of arsenic speciation and bioaccessibility in mine-impacted materials. Diana Aga, Wonyong Choi, Andrew Daugulis, Gianluca Li Puma, Gerasimos Lyberatos, and Joo Hwa Tay JOURNAL OF HAZARDOUS MATERIALS. Elsevier Science Ltd, New York, NY, USA, 313: 130-137, (2016).

Cultural adaptation of an instrument to assess physical fitness in cardiac patients.

PubMed

Domingues, Gabriela de Barros Leite; Gallani, Maria Cecília; Gobatto, Claudio Alexandre; Miura, Cinthya Tamie Passos; Rodrigues, Roberta Cunha Matheus; Myers, Jonathan

2011-04-01

To validate the content and to evaluate the reliability of the Veterans Specific Activity Questionnaire instrument, culturally adapted for use in the Brazilian population of cardiac patients. The instrument was translated and back-translated and subsequently analyzed by a committee of judges to evaluate its semantic-idiomatic and cultural equivalences. Physical activities were replaced when indicated in the instrument, but uncommon in the daily life of the target population. Another committee of specialists analyzed the metabolic equivalence of replaced activities. The proportion of agreement of evaluation of the judges was quantified by the Content Validity Index. The pre-test was performed in two stages (n1 and n2=15). Reliability was assessed using the test-retest (interval of 7-15 days, n = 50). In the evaluation of semantic-idiomatic and cultural equivalences, items with a Content Validity Index < 1 were reviewed until consensus among the judges was obtained. The second committee found 100% of agreement in the analysis of metabolic equivalence between original and replaced activities. Test-retest analysis indicated a Kappa coefficient of agreement (k = 0.86; (p<0.001), suggesting temporal stability of the instrument. The Brazilian version of the Veterans Specific Activity Questionnaire showed evidence of reliability, according to the temporal stability criterion and adequate cultural content.

Curriculum-Based Measurement of Oral Reading: Passage Equivalence and Probe-Set Development

ERIC Educational Resources Information Center

Christ, Theodore J.; Ardoin, Scott P.

2009-01-01

Curriculum-based measurement of reading (CBM-R) is used to estimate oral reading fluency. Unlike many traditional published tests, CBM-R materials are often comprised of 20 to 30 alternate forms/passages. Historically, CBM-R assessment materials were sampled from curricular materials. Recent research has documented the potentially deleterious…

46 CFR 160.076-17 - Approval of design or material changes.

Code of Federal Regulations, 2010 CFR

2010-10-01

... approval before changing PFD production methods. (b) Determinations of equivalence of design, construction... 46 Shipping 6 2010-10-01 2010-10-01 false Approval of design or material changes. 160.076-17... Flotation Devices § 160.076-17 Approval of design or material changes. (a) The manufacturer must submit any...

46 CFR 160.077-7 - Procedure for approval of design or material revision.

Code of Federal Regulations, 2010 CFR

2010-10-01

... being used in any production of PFDs. (b) Determinations of equivalence of design, construction, and... 46 Shipping 6 2010-10-01 2010-10-01 false Procedure for approval of design or material revision... Personal Flotation Devices § 160.077-7 Procedure for approval of design or material revision. (a) Each...

Neuronal boost to evolutionary dynamics

PubMed Central

de Vladar, Harold P.; Szathmáry, Eörs

2015-01-01

Standard evolutionary dynamics is limited by the constraints of the genetic system. A central message of evolutionary neurodynamics is that evolutionary dynamics in the brain can happen in a neuronal niche in real time, despite the fact that neurons do not reproduce. We show that Hebbian learning and structural synaptic plasticity broaden the capacity for informational replication and guided variability provided a neuronally plausible mechanism of replication is in place. The synergy between learning and selection is more efficient than the equivalent search by mutation selection. We also consider asymmetric landscapes and show that the learning weights become correlated with the fitness gradient. That is, the neuronal complexes learn the local properties of the fitness landscape, resulting in the generation of variability directed towards the direction of fitness increase, as if mutations in a genetic pool were drawn such that they would increase reproductive success. Evolution might thus be more efficient within evolved brains than among organisms out in the wild. PMID:26640653

Role models for complex networks

NASA Astrophysics Data System (ADS)

Reichardt, J.; White, D. R.

2007-11-01

We present a framework for automatically decomposing (“block-modeling”) the functional classes of agents within a complex network. These classes are represented by the nodes of an image graph (“block model”) depicting the main patterns of connectivity and thus functional roles in the network. Using a first principles approach, we derive a measure for the fit of a network to any given image graph allowing objective hypothesis testing. From the properties of an optimal fit, we derive how to find the best fitting image graph directly from the network and present a criterion to avoid overfitting. The method can handle both two-mode and one-mode data, directed and undirected as well as weighted networks and allows for different types of links to be dealt with simultaneously. It is non-parametric and computationally efficient. The concepts of structural equivalence and modularity are found as special cases of our approach. We apply our method to the world trade network and analyze the roles individual countries play in the global economy.

Cardiorespiratory Fitness and Long-Term Survival in “Low-Risk” Adults

PubMed Central

Barlow, Carolyn E.; DeFina, Laura F.; Radford, Nina B.; Berry, Jarett D.; Cooper, Kenneth H.; Haskell, William L.; Jones, Lee W.; Lakoski, Susan G.

2012-01-01

Background We sought to establish whether cardiorespiratory fitness had important implications for long-term cardiovascular risk among individuals classified as low risk by the Framingham Risk Score (10-year coronary heart disease risk <10%). Prognostic factors of long-term cardiovascular risk are needed for low-risk subjects who make up the largest percentage of the US population. Methods and Results The study population was composed of men and women, 30 to 50 years of age, who had a baseline medical exam at the Cooper Clinic, Dallas, TX, between 1970 and 1983. Eligible individuals were defined as at low risk for coronary heart disease by Framingham Risk Score at the time of study entry and had no history of diabetes (n=11 190). Cardiorespiratory fitness was determined by maximum graded exercise treadmill tests. Over an average 27±2-year period, 15% of low-fit (quintile 1) compared to 6% of high-fit (quintile 5) individuals died (P<0.001). A 1–metabolic equivalent level increase in baseline fitness was associated with an 11% reduction in all-cause deaths and an 18% reduction in deaths due to cardiovascular disease (CVD) after adjustment for age, sex, body mass index, systolic blood pressure, total cholesterol, blood glucose levels, smoking, and early family history of coronary disease. There was an incremental decrease in CVD risk with increasing fitness quintile, such that the high fit had the lowest adjusted 30-year CVD mortality rate (hazard ratio 0.29, 95% CI: 0.16–0.51) compared to the low fit. Conclusions Cardiorespiratory fitness is associated with a significant reduction in long-term CVD among individuals identified as low risk by Framingham Risk Score. These data suggest that preventive lifestyle interventions geared to optimize cardiorespiratory fitness, even among a “low-risk” subset, should be considered to improve CVD-free survival. (J Am Heart Assoc. 2012;1:e001354 doi: 10.1161/JAHA.112.001354.) PMID:23130161

Basis material decomposition method for material discrimination with a new spectrometric X-ray imaging detector

NASA Astrophysics Data System (ADS)

Brambilla, A.; Gorecki, A.; Potop, A.; Paulus, C.; Verger, L.

2017-08-01

Energy sensitive photon counting X-ray detectors provide energy dependent information which can be exploited for material identification. The attenuation of an X-ray beam as a function of energy depends on the effective atomic number Zeff and the density. However, the measured attenuation is degraded by the imperfections of the detector response such as charge sharing or pile-up. These imperfections lead to non-linearities that limit the benefits of energy resolved imaging. This work aims to implement a basis material decomposition method which overcomes these problems. Basis material decomposition is based on the fact that the attenuation of any material or complex object can be accurately reproduced by a combination of equivalent thicknesses of basis materials. Our method is based on a calibration phase to learn the response of the detector for different combinations of thicknesses of the basis materials. The decomposition algorithm finds the thicknesses of basis material whose spectrum is closest to the measurement, using a maximum likelihood criterion assuming a Poisson law distribution of photon counts for each energy bin. The method was used with a ME100 linear array spectrometric X-ray imager to decompose different plastic materials on a Polyethylene and Polyvinyl Chloride base. The resulting equivalent thicknesses were used to estimate the effective atomic number Zeff. The results are in good agreement with the theoretical Zeff, regardless of the plastic sample thickness. The linear behaviour of the equivalent lengths makes it possible to process overlapped materials. Moreover, the method was tested with a 3 materials base by adding gadolinium, whose K-edge is not taken into account by the other two materials. The proposed method has the advantage that it can be used with any number of energy channels, taking full advantage of the high energy resolution of the ME100 detector. Although in principle two channels are sufficient, experimental measurements show that the use of a high number of channels significantly improves the accuracy of decomposition by reducing noise and systematic bias.

Quality assurance in the production of pipe fittings by automatic laser-based material identification

NASA Astrophysics Data System (ADS)

Moench, Ingo; Peter, Laszlo; Priem, Roland; Sturm, Volker; Noll, Reinhard

1999-09-01

In plants of the chemical, nuclear and off-shore industry, application specific high-alloyed steels are used for pipe fittings. Mixing of different steel grades can lead to corrosion with severe consequential damages. Growing quality requirements and environmental responsibilities demand a 100% material control in the production of the pipe fittings. Therefore, LIFT, an automatic inspection machine, was developed to insure against any mix of material grades. LIFT is able to identify more than 30 different steel grades. The inspection method is based on Laser-Induced Breakdown Spectrometry (LIBS). An expert system, which can be easily trained and recalibrated, was developed for the data evaluation. The result of the material inspection is transferred to an external handling system via a PLC interface. The duration of the inspection process is 2 seconds. The graphical user interface was developed with respect to the requirements of an unskilled operator. The software is based on a realtime operating system and provides a safe and reliable operation. An interface for the remote maintenance by modem enables a fast operational support. Logged data are retrieved and evaluated. This is the basis for an adaptive improvement of the configuration of LIFT with respect to changing requirements in the production line. Within the first six months of routine operation, about 50000 pipe fittings were inspected.

Final report on CCQM-K80: Comparison of value-assigned CRMs and PT materials: Creatinine in human serum

NASA Astrophysics Data System (ADS)

Camara, Johanna E.; Duewer, David L.; Gasca Aragon, Hugo; Lippa, Katrice A.; Toman, Blaza

2013-01-01

The 2009 CCQM-K80 'Comparison of value-assigned CRMs and PT materials: creatinine in human serum' is the first in a series of key comparisons directly testing the chemical measurement services provided to customers by National Metrology Institutes (NMIs) and Designated Institutes. CCQM-K80 compared the assigned serum creatinine values of certified reference materials (CRMs) using measurements made on these materials under repeatability conditions. Six NMIs submitted 17 CRM materials for evaluation, all intended for sale to customers. These materials represent nearly all of the higher-order CRMs then available for this clinically important measurand. The certified creatinine mass fraction in the materials ranged from 3 mg/kg to 57 mg/kg. All materials were stored and prepared according the specifications provided by each NMI. Samples were processed and analyzed under repeatability conditions by one analyst using isotope dilution liquid chromatography-mass spectrometry. The instrumental repeatability imprecision, expressed as a percent relative standard deviation, was 1.2%. Given the number of materials and the time required for each analysis, the measurements were made in two measurement campaigns ('runs'). In both campaigns, replicate analyses (two injections of one preparation separated in time) were made on each of two or three independently prepared aliquots from one randomly selected unit of each of the 17 materials. The mean value, between-campaign, between-aliquot and between-replicate variance components, standard uncertainty of the mean value, and the number of degrees of freedom associated with the standard uncertainty were estimated using a linear mixed model. Since several of the uncertainties estimated using this traditional frequentist approach were associated with a single degree of freedom, Markov Chain Monte Carlo Bayesian analysis was used to estimate 95% level-of-confidence coverage intervals, U95. Uncertainty-weighted generalized distance regression was used to establish the key comparison reference function (KCRF) relating the assigned values to the repeatability measurements. Parametric bootstrap Monte Carlo was used to estimate 95% level-of-confidence coverage intervals for the degrees of equivalence of materials, d +/- U95(d), and of the participating NMIs, D +/- U95(D). Because of the wide range of creatinine mass fraction in the materials, these degrees of equivalence are expressed in percent relative form: %d +/- U95(%d) and %D +/- U95(%D). On the basis of leave-one-out cross-validation, the assigned values for 16 of the 17 materials were deemed equivalent at the 95% level of confidence. These materials were used to define the KCRF. The excluded material was identified as having a marginally underestimated assigned uncertainty, giving it large and potentially anomalous influence on the KCRF. However, this material's %d of 1.4 +/- 1.5 indicates that it is equivalent with the other materials at the 95% level of confidence. The median |%d| for all 17 of the materials is 0.3 with a median U95(%d) of 1.9. All of these higher-order CRMs for creatinine in human serum are equivalent within their assigned uncertainties. The median |%D| for the participating NMIs is 0.3 with a median U95(%D) of 2.1. These results demonstrate that all participating NMIs have the ability to correctly value-assign CRMs and proficiency test materials for creatinine in human serum and similar measurands. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

40 CFR 63.3370 - How do I demonstrate compliance with the emission standards?

Code of Federal Regulations, 2014 CFR

2014-07-01

... equivalent allowable organic HAP (Equation 13a or b of § 63.3370). (4) Use of a capture system and control... control devices (i) Average equivalent organic HAP emission rate does not exceed 0.2 kg organic HAP per kg... material applied on the web coating line or group of web coating lines controlled by a common control...

40 CFR 63.3370 - How do I demonstrate compliance with the emission standards?

Code of Federal Regulations, 2012 CFR

2012-07-01

... equivalent allowable organic HAP (Equation 13a or b of § 63.3370). (4) Use of a capture system and control... control devices (i) Average equivalent organic HAP emission rate does not exceed 0.2 kg organic HAP per kg... material applied on the web coating line or group of web coating lines controlled by a common control...

40 CFR 63.3370 - How do I demonstrate compliance with the emission standards?

Code of Federal Regulations, 2013 CFR

2013-07-01

... equivalent allowable organic HAP (Equation 13a or b of § 63.3370). (4) Use of a capture system and control... control devices (i) Average equivalent organic HAP emission rate does not exceed 0.2 kg organic HAP per kg... material applied on the web coating line or group of web coating lines controlled by a common control...

Equivalence between short-time biphasic and incompressible elastic material responses.

PubMed

Ateshian, Gerard A; Ellis, Benjamin J; Weiss, Jeffrey A

2007-06-01

Porous-permeable tissues have often been modeled using porous media theories such as the biphasic theory. This study examines the equivalence of the short-time biphasic and incompressible elastic responses for arbitrary deformations and constitutive relations from first principles. This equivalence is illustrated in problems of unconfined compression of a disk, and of articular contact under finite deformation, using two different constitutive relations for the solid matrix of cartilage, one of which accounts for the large disparity observed between the tensile and compressive moduli in this tissue. Demonstrating this equivalence under general conditions provides a rationale for using available finite element codes for incompressible elastic materials as a practical substitute for biphasic analyses, so long as only the short-time biphasic response is sought. In practice, an incompressible elastic analysis is representative of a biphasic analysis over the short-term response deltat

Development of Equivalent Material Properties of Microbump for Simulating Chip Stacking Packaging

PubMed Central

Lee, Chang-Chun; Tzeng, Tzai-Liang; Huang, Pei-Chen

2015-01-01

A three-dimensional integrated circuit (3D-IC) structure with a significant scale mismatch causes difficulty in analytic model construction. This paper proposes a simulation technique to introduce an equivalent material composed of microbumps and their surrounding wafer level underfill (WLUF). The mechanical properties of this equivalent material, including Young’s modulus (E), Poisson’s ratio, shear modulus, and coefficient of thermal expansion (CTE), are directly obtained by applying either a tensile load or a constant displacement, and by increasing the temperature during simulations, respectively. Analytic results indicate that at least eight microbumps at the outermost region of the chip stacking structure need to be considered as an accurate stress/strain contour in the concerned region. In addition, a factorial experimental design with analysis of variance is proposed to optimize chip stacking structure reliability with four factors: chip thickness, substrate thickness, CTE, and E-value. Analytic results show that the most significant factor is CTE of WLUF. This factor affects microbump reliability and structural warpage under a temperature cycling load and high-temperature bonding process. WLUF with low CTE and high E-value are recommended to enhance the assembly reliability of the 3D-IC architecture. PMID:28793495

49 CFR 179.300-12 - Protection of fittings.

Code of Federal Regulations, 2012 CFR

2012-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-12 Protection of fittings. (a...

49 CFR 179.300-12 - Protection of fittings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-12 Protection of fittings. (a...

Theory and application of equivalent transformation relationships between plane wave and spherical wave

NASA Astrophysics Data System (ADS)

Wang, Yao; Yang, Zailin; Zhang, Jianwei; Yang, Yong

2017-10-01

Based on the governing equations and the equivalent models, we propose an equivalent transformation relationships between a plane wave in a one-dimensional medium and a spherical wave in globular geometry with radially inhomogeneous properties. These equivalent relationships can help us to obtain the analytical solutions of the elastodynamic issues in an inhomogeneous medium. The physical essence of the presented equivalent transformations is the equivalent relationships between the geometry and the material properties. It indicates that the spherical wave problem in globular geometry can be transformed into the plane wave problem in the bar with variable property fields, and its inverse transformation is valid as well. Four different examples of wave motion problems in the inhomogeneous media are solved based on the presented equivalent relationships. We obtain two basic analytical solution forms in Examples I and II, investigate the reflection behavior of inhomogeneous half-space in Example III, and exhibit a special inhomogeneity in Example IV, which can keep the traveling spherical wave in constant amplitude. This study implies that our idea makes solving the associated problem easier.

Proportional-scanning-phase method to suppress the vibrational noise in nonisotope dual-atom-interferometer-based weak-equivalence-principle-test experiments

NASA Astrophysics Data System (ADS)

Chen, Xi; Zhong, Jiaqi; Song, Hongwei; Zhu, Lei; Wang, Jin; Zhan, Mingsheng

2014-08-01

Vibrational noise is one of the most important noises that limits the performance of the nonisotopes atom-interferometers (AIs) -based weak-equivalence-principle (WEP) -test experiment. By analyzing the vibration-induced phases, we find that, although the induced phases are not completely common, their ratio is always a constant at every experimental data point, which is not fully utilized in the traditional elliptic curve-fitting method. From this point, we propose a strategy that can greatly suppress the vibration-induced phase noise by stabilizing the Raman laser frequencies at high precision and controlling the scanning-phase ratio. The noise rejection ratio can be as high as 1015 with arbitrary dual-species AIs. Our method provides a Lissajous curve, and the shape of the curve indicates the breakdown of the weak-equivalence-principle signal. Then we manage to derive an estimator for the differential phase of the Lissajous curve. This strategy could be helpful in extending the candidates of atomic species for high-precision AIs-based WEP-test experiments.

Equivalent circuit for the characterization of the resonance mode in piezoelectric systems

NASA Astrophysics Data System (ADS)

Fernández-Afonso, Y.; García-Zaldívar, O.; Calderón-Piñar, F.

2015-12-01

The impedance properties in polarized piezoelectric can be described by electric equivalent circuits. The classic circuit used in the literature to describe real systems is formed by one resistor (R), one inductance (L) and one capacitance C connected in series and one capacity (C0) connected in parallel with the formers. Nevertheless, the equation that describe the resonance and anti-resonance frequencies depends on a complex manner of R, L, C and C0. In this work is proposed a simpler model formed by one inductance (L) and one capacity (C) in series; one capacity (C0) in parallel; one resistor (RP) in parallel and one resistor (RS) in series with other components. Unlike the traditional circuit, the equivalent circuit elements in the proposed model can be simply determined by knowing the experimental values of the resonance frequency fr, anti-resonance frequency fa, impedance module at resonance frequency |Zr|, impedance module at anti-resonance frequency |Za| and low frequency capacitance C0, without fitting the impedance experimental data to the obtained equation.

Two Equivalent Methyl Internal Rotations in 2,5-DIMETHYLTHIOPHENE Investigated by Microwave Spectroscopy

NASA Astrophysics Data System (ADS)

Van, Vinh; Stahl, Wolfgang; Nguyen, Ha Vinh Lam

2016-06-01

The microwave spectrum of 2,5-dimethylthiophene, a sulfur-containing five-membered heterocyclic molecule with two conjugated double bonds, was recorded using two molecular beam Fourier transform microwave spectrometers operating in the frequency range from 2 to 40 GHz. Highly accurate molecular parameters were determined. The rotational constants obtained by geometry optimizations at different levels of theory are in good agreement with the experimental values. A C2v equilibrium structure was calculated, where one hydrogen atom of each methyl group is antiperiplanar to the sulfur atom, and the two methyl groups are thus equivalent. Transition states were optimized at different levels of theory using the Berny algorithm to calculate the barrier height of the two equivalent methyl rotors. The fitted experimental torsional barrier of 247.95594(30) wn is in reasonable agreement with the calculated barriers. Similar barriers to internal rotation were found for the monomethyl derivatives 2-methylthiophene (194.1 wn) and 3-methylthiophene (258.8 wn). A labeling scheme for the group G36 written as the semi-direct product (C3I x C3I) (x C2v was introduced.

Experimental Determination of Aerodynamic Damping in a Three-Stage Transonic Axial-Flow Compressor. Degree awarded by Case Western Reserve Univ.

NASA Technical Reports Server (NTRS)

Newman, Frederick A.

1988-01-01

Rotor blade aerodynamic damping is experimentally determined in a three-stage transonic axial flow compressor having design aerodynamic performance goals of 4.5:1 pressure ratio and 65.5 lbm/sec weight flow. The combined damping associated with each mode is determined by a least squares fit of a single degree of freedom system transfer function to the nonsynchronous portion of the rotor blade strain gauge output power spectra. The combined damping consists of aerodynamic and structural and mechanical damping. The aerodynamic damping varies linearly with the inlet total pressure for a given equivalent speed, equivalent mass flow, and pressure ratio while structural and mechanical damping are assumed to be constant. The combined damping is determined at three inlet total pressure levels to obtain the aerodynamic damping. The third stage rotor blade aerodynamic damping is presented and discussed for 70, 80, 90, and 100 percent design equivalent speed. The compressor overall performance and experimental Campbell diagrams for the third stage rotor blade row are also presented.

Modeling the thermal structure and magnetic properties of the crust of active regions with application to the Rio Grande rift

NASA Technical Reports Server (NTRS)

1982-01-01

Experiments in Curie depth estimation from long wavelength magnetic anomalies are summarized. The heart of the work is equivalent-layer-type magnetization models derived by inversion of high-elevation, long wavelength magnetic anomaly data. The methodology is described in detail in the above references. A magnetization distribution in a thin equivalent layer at the Earth's surface having maximum detail while retaining physical significance, and giving rise to a synthetic anomaly field which makes a best fit to the observed field in a least squares sense is discussed. The apparent magnetization contrast in the equivalent layer is approximated using an array of dipoles distributed in equal area at the Earth's surface. The dipoles are pointed in the direction of the main magnetic field, which carries the implicit assumption that crustal magnetization is dominantly induced or viscous. The determination of the closest possible dipole spacing giving a stable inversion to a solution having physical significance is accomplished by plotting the standard deviation of the solution parameters against their spatial separation for a series of solutions.

Fitting Higgs data with nonlinear effective theory.

PubMed

Buchalla, G; Catà, O; Celis, A; Krause, C

2016-01-01

In a recent paper we showed that the electroweak chiral Lagrangian at leading order is equivalent to the conventional [Formula: see text] formalism used by ATLAS and CMS to test Higgs anomalous couplings. Here we apply this fact to fit the latest Higgs data. The new aspect of our analysis is a systematic interpretation of the fit parameters within an EFT. Concentrating on the processes of Higgs production and decay that have been measured so far, six parameters turn out to be relevant: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]. A global Bayesian fit is then performed with the result [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]. Additionally, we show how this leading-order parametrization can be generalized to next-to-leading order, thus improving the [Formula: see text] formalism systematically. The differences with a linear EFT analysis including operators of dimension six are also discussed. One of the main conclusions of our analysis is that since the conventional [Formula: see text] formalism can be properly justified within a QFT framework, it should continue to play a central role in analyzing and interpreting Higgs data.

Application of Athletic Movement Tests that Predict Injury Risk in a Military Population: Development of Normative Data.

PubMed

Teyhen, Deydre S; Shaffer, Scott W; Butler, Robert J; Goffar, Stephen L; Kiesel, Kyle B; Rhon, Daniel I; Boyles, Robert E; McMillian, Daniel J; Williamson, Jared N; Plisky, Phillip J

2016-10-01

Performance on movement tests helps to predict injury risk in a variety of physically active populations. Understanding baseline measures for normal is an important first step. Determine differences in physical performance assessments and describe normative values for these tests based on military unit type. Assessment of power, balance, mobility, motor control, and performance on the Army Physical Fitness Test were assessed in a cohort of 1,466 soldiers. Analysis of variance was performed to compare the results based on military unit type (Rangers, Combat, Combat Service, and Combat Service Support) and analysis of covariance was performed to determine the influence of age and gender. Rangers performed the best on all performance and fitness measures (p < 0.05). Combat soldiers performed better than Combat Service and Service Support soldiers on several physical performance tests and the Army Physical Fitness Test (p < 0.05). Performance in Combat Service and Service Support soldiers was equivalent on most measures (p < 0.05). Functional performance and level of fitness varied significantly by military unit type. Understanding these differences will provide a foundation for future injury prediction and prevention strategies. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

Advertising Content in Physical Activity Print Materials.

ERIC Educational Resources Information Center

Cardinal, Bradley J.

2002-01-01

Evaluated the advertising content contained in physical activity print materials. Analysis of print materials obtained from 80 sources (e.g., physicians' offices and fitness events) indicated that most materials contained some form of advertising. Materials coming from commercial product vendors generally contained more advertising than materials…

Leak test fitting

DOEpatents

Pickett, P.T.

A hollow fitting for use in gas spectrometry leak testing of conduit joints is divided into two generally symmetrical halves along the axis of the conduit. A clip may quickly and easily fasten and unfasten the halves around the conduit joint under test. Each end of the fitting is sealable with a yieldable material, such as a piece of foam rubber. An orifice is provided in a wall of the fitting for the insertion or detection of helium during testing. One half of the fitting also may be employed to test joints mounted against a surface.

Leak test fitting

DOEpatents

Pickett, Patrick T.

1981-01-01

A hollow fitting for use in gas spectrometry leak testing of conduit joints is divided into two generally symmetrical halves along the axis of the conduit. A clip may quickly and easily fasten and unfasten the halves around the conduit joint under test. Each end of the fitting is sealable with a yieldable material, such as a piece of foam rubber. An orifice is provided in a wall of the fitting for the insertion or detection of helium during testing. One half of the fitting also may be employed to test joints mounted against a surface.

A comparison of fit of CNC-milled titanium and zirconia frameworks to implants.

PubMed

Abduo, Jaafar; Lyons, Karl; Waddell, Neil; Bennani, Vincent; Swain, Michael

2012-05-01

Computer numeric controlled (CNC) milling was proven to be predictable method to fabricate accurately fitting implant titanium frameworks. However, no data are available regarding the fit of CNC-milled implant zirconia frameworks. To compare the precision of fit of implant frameworks milled from titanium and zirconia and relate it to peri-implant strain development after framework fixation. A partially edentulous epoxy resin models received two Branemark implants in the areas of the lower left second premolar and second molar. From this model, 10 identical frameworks were fabricated by mean of CNC milling. Half of them were made from titanium and the other half from zirconia. Strain gauges were mounted close to the implants to qualitatively and quantitatively assess strain development as a result of framework fitting. In addition, the fit of the framework implant interface was measured using an optical microscope, when only one screw was tightened (passive fit) and when all screws were tightened (vertical fit). The data was statistically analyzed using the Mann-Whitney test. All frameworks produced measurable amounts of peri-implant strain. The zirconia frameworks produced significantly less strain than titanium. Combining the qualitative and quantitative information indicates that the implants were under vertical displacement rather than horizontal. The vertical fit was similar for zirconia (3.7 µm) and titanium (3.6 µm) frameworks; however, the zirconia frameworks exhibited a significantly finer passive fit (5.5 µm) than titanium frameworks (13.6 µm). CNC milling produced zirconia and titanium frameworks with high accuracy. The difference between the two materials in terms of fit is expected to be of minimal clinical significance. The strain developed around the implants was more related to the framework fit rather than framework material. © 2011 Wiley Periodicals, Inc.

Impact of Fractionation and Dose in a Multivariate Model for Radiation-Induced Chest Wall Pain

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

Din, Shaun U.; Williams, Eric L.; Jackson, Andrew

Purpose: To determine the role of patient/tumor characteristics, radiation dose, and fractionation using the linear-quadratic (LQ) model to predict stereotactic body radiation therapy–induced grade ≥2 chest wall pain (CWP2) in a larger series and develop clinically useful constraints for patients treated with different fraction numbers. Methods and Materials: A total of 316 lung tumors in 295 patients were treated with stereotactic body radiation therapy in 3 to 5 fractions to 39 to 60 Gy. Absolute dose–absolute volume chest wall (CW) histograms were acquired. The raw dose-volume histograms (α/β = ∞ Gy) were converted via the LQ model to equivalent doses in 2-Gy fractions (normalizedmore » total dose, NTD) with α/β from 0 to 25 Gy in 0.1-Gy steps. The Cox proportional hazards (CPH) model was used in univariate and multivariate models to identify and assess CWP2 exposed to a given physical and NTD. Results: The median follow-up was 15.4 months, and the median time to development of CWP2 was 7.4 months. On a univariate CPH model, prescription dose, prescription dose per fraction, number of fractions, D83cc, distance of tumor to CW, and body mass index were all statistically significant for the development of CWP2. Linear-quadratic correction improved the CPH model significance over the physical dose. The best-fit α/β was 2.1 Gy, and the physical dose (α/β = ∞ Gy) was outside the upper 95% confidence limit. With α/β = 2.1 Gy, V{sub NTD99Gy} was most significant, with median V{sub NTD99Gy} = 31.5 cm{sup 3} (hazard ratio 3.87, P<.001). Conclusion: There were several predictive factors for the development of CWP2. The LQ-adjusted doses using the best-fit α/β = 2.1 Gy is a better predictor of CWP2 than the physical dose. To aid dosimetrists, we have calculated the physical dose equivalent corresponding to V{sub NTD99Gy} = 31.5 cm{sup 3} for the 3- to 5-fraction groups.« less

Association among sickle cell trait, fitness, and cardiovascular risk factors in CARDIA.

PubMed

Liem, Robert I; Chan, Cheeling; Vu, Thanh-Huyen T; Fornage, Myriam; Thompson, Alexis A; Liu, Kiang; Carnethon, Mercedes R

2017-02-09

The contribution of sickle cell trait (SCT) to racial disparities in cardiopulmonary fitness is not known, despite concerns that SCT is associated with exertion-related sudden death. We evaluated the association of SCT status with cross-sectional and longitudinal changes in fitness and risk for hypertension, diabetes, and metabolic syndrome over the course of 25 years among 1995 African Americans (56% women, 18-30 years old) in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Overall, the prevalence of SCT was 6.8% (136/1995) in CARDIA, and over the course of 25 years, 46% (738/1590), 18% (288/1631), and 40% (645/1,611) of all participants developed hypertension, diabetes, and metabolic syndrome, respectively. Compared with participants without SCT, participants with SCT had similar baseline measures of fitness in cross-section, including exercise duration (535 vs 540 seconds; P = .62), estimated metabolic equivalent of tasks (METs; 11.6 vs 11.7; P = .80), maximum heart rate (174 vs 175 beats/min; P = .41), and heart rate at 2 minutes recovery (44 vs 43 beats/min; P = .28). In our secondary analysis, there was neither an association of SCT status with longitudinal changes in fitness nor an association with development of hypertension, diabetes, or metabolic syndrome after adjustment for sex, baseline age, body mass index, fitness, and physical activity. SCT is not associated with reduced fitness in this longitudinal study of young African American adults, suggesting the increased risk for exertion-related sudden death in SCT carriers is unlikely related to fitness. SCT status also is not an independent risk factor for developing hypertension, diabetes, or metabolic syndrome. © 2017 by The American Society of Hematology.

Characterizing differences in mortality at the low end of the fitness spectrum in individuals with cardiovascular disease.

PubMed

Mandic, Sandra; Myers, Jonathan; Oliveira, Ricardo B; Abella, Joshua; Froelicher, Victor F

2010-06-01

A graded but nonlinear relationship exists between fitness and mortality, with the greatest mortality differences occurring between the least-fit (first, Q1) and the next-least-fit (second, Q2) quintiles of fitness. The purpose of this study was to compare clinical characteristics, exercise test responses, and physical activity (PA) patterns in Q1 versus Q2 in patients with cardiovascular disease (CVD). Observational retrospective study. A total of 5101 patients with a history of CVD underwent clinical treadmill testing and were followed up for 9.1+/-5.5 years. Patients were classified into quintiles of exercise capacity measured in metabolic equivalents. Clinical characteristics, treadmill test results, and recreational PA patterns were compared between Q1 (n = 923) and Q2 (n = 929). Q1 had a nearly two-fold increase in age-adjusted relative risk of cardiovascular mortality compared with Q2 (hazard ratio: 3.79 vs. 2.04, P<0.05; reference: fittest quintile). Q1 patients were older, had more extensive use of medications, and were more likely to have a history of typical angina (35 vs. 28%), myocardial infarction (30 vs. 24%), chronic heart failure (25 vs. 14%), claudication (15 vs. 9%) and stroke (9 vs. 6%) compared with Q2 (all comparisons: P<0.05). Recent and lifetime recreational PA was not different between the two groups. Greater severity of disease in the least-fit versus the next-least-fit quintile likely contributes to but cannot fully explain marked differences in mortality rates in CVD patients. To achieve potential survival benefits, our results suggest that unfit CVD patients should engage in exercise programs of sufficient volume and intensity to improve fitness.

LONGITUDINAL PATTERNS OF CARDIORESPIRATORY FITNESS PREDICT THE DEVELOPMENT OF HYPERTENSION AMONG MEN AND WOMEN

PubMed Central

Sui, Xuemei; Sarzynski, Mark A.; Lee, Duck-chul; Lavie, Carl J.; Zhang, Jiajia; Kokkinos, Peter F.; Payne, Jonathan; Blair, Steven N.

2016-01-01

Background Most of the existing literature has linked either a baseline cardiorespiratory fitness, or change between baseline and one follow-up measurement of cardiorespiratory fitness, to hypertension. The purpose of the study is to assess the association between longitudinal patterns of cardiorespiratory fitness changes with time and incident hypertension in adult men and women. Patients and Methods Participants were aged from 20 to 82 years, free of hypertension during the first three examinations, and received at least four preventive medical examinations at the Cooper Clinic in Dallas, TX, during 1971 – 2006. They were classified into one of five groups based on all of the measured cardiorespiratory fitness values (in metabolic equivalents) during maximal treadmill tests. Logistic regression was used to compute odds ratios and 95% confidence intervals. Results Among a total of 4,932 participants (13% women), 1,954 developed hypertension. After controlling for baseline potential confounders, follow-up duration, and number of follow-up visits, odds ratios (95% confidence intervals) for hypertension were: 1.00 for decreasing group (referent), 0.64 (0.52–0.80) for increasing, 0.89 (0.70–1.12) for Bell-shape, 0.78 (0.62–0.98) for U-shape, and 0.83 (0.69–1.00) for inconsistent group. The general pattern of the association was consistent regardless of participants’ baseline cardiorespiratory fitness or body mass index levels. Conclusion An increasing pattern of cardiorespiratory fitness provides the lowest risk of hypertension in this middle-aged relatively healthy population. Identifying specific pattern(s) of cardiorespiratory fitness change may be important for determining associations with comorbidity such as hypertension. PMID:27986522

Cardiorespiratory fitness, BMI, and risk of hypertension: the HYPGENE study.

PubMed

Rankinen, Tuomo; Church, Timothy S; Rice, Treva; Bouchard, Claude; Blair, Steven N

2007-10-01

Cardiorespiratory fitness and regular physical activity are inversely associated with the risk of hypertension, and exercise training has been shown to lower elevated blood pressure (BP). Genetic factors contribute significantly to the interindividual differences in endurance training-induced changes in BP. However, similar data on the genotype-by-fitness interactions on the risk of hypertension are scarce. In 2000, we started a systematic collection of blood samples from all consenting subjects of the Aerobics Center Longitudinal Study (ACLS) with a goal to generate a resource for studies addressing genotype-by-fitness interaction effects on various health-related end points. Here, we introduce the rationale and design of the first study based on the ACLS genetics resource focusing on hypertension as the health outcome (HYPGENE study), and we report the associations of cardiorespiratory fitness and body mass index (BMI) with the risk of hypertension. All HYPGENE subjects (N = 1234) were healthy and normotensive at their first clinic visit. Cases (N = 629) developed hypertension during the follow-up period (mean 8.7 yr), whereas controls (N = 605) remained normotensive (mean follow-up 10.1 yr). Cardiorespiratory fitness was the strongest predictor of the hypertension risk, with each maximal metabolic equivalent unit being associated with a 19% lower risk (95% confidence interval [95% CI], 12-24%). Each baseline BMI unit was associated with a 9% higher hypertension risk (95% CI, 4-13%). However, the association of BMI was greatly attenuated (odds ratio 1.04 [95% CI, 0.99-1.09]) when fitness also was included in the model. The HYPGENE study will provide an excellent resource to address hypotheses regarding the genetic basis of hypertension while taking cardiorespiratory fitness level into account.

Cardiorespiratory Fitness Change and Mortality Risk Among Black and White Patients: Henry Ford Exercise Testing (FIT) Project.

PubMed

Ehrman, Jonathan K; Brawner, Clinton A; Al-Mallah, Mouaz H; Qureshi, Waqas T; Blaha, Michael J; Keteyian, Steven J

2017-10-01

Little is known about the relationship of change in cardiorespiratory fitness and mortality risk in Black patients. This study assessed change in cardiorespiratory fitness and its association with all-cause mortality risk in Black and White patients. This is a retrospective, longitudinal, observational cohort study of 13,345 patients (age = 55 ± 11 years; 39% women; 26% black) who completed 2 exercise tests, at least 12 months apart at Henry Ford Hospital, Detroit, Mich. All-cause mortality was identified through April 2013. Data were analyzed in 2015-2016 using Cox regression to calculate hazard ratios (HR) for risk of mortality associated with change in sex-specific cardiorespiratory fitness. Mean time between the tests was 3.4 years (interquartile range 1.9-5.6 years). During 9.1 years (interquartile range 6.3-11.6 years) of follow-up, there were 1931 (14%) deaths (16.5% black, 13.7% white). For both races, change in fitness from Low to the Intermediate/High category resulted in a significant reduction of death risk (HR 0.65 [95% confidence interval (CI), 0.49-0.87] for Black; HR 0.41 [95% CI, 0.34-0.51] for White). Each 1-metabolic-equivalent-of-task increase was associated with a reduced mortality risk in black (HR 0.84 [95% CI, 0.81-0.89]) and white (HR 0.87 [95% CI, 0.82-0.86]) patients. There was no interaction by race. Among black and white patients, change in cardiorespiratory fitness from Low to Intermediate/High fitness was associated with a 35% and 59% lower risk of all-cause mortality, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

Exercise capacity and progression from prehypertension to hypertension.

PubMed

Faselis, Charles; Doumas, Michael; Kokkinos, John Peter; Panagiotakos, Demosthenes; Kheirbek, Raya; Sheriff, Helen M; Hare, Katherine; Papademetriou, Vasilios; Fletcher, Ross; Kokkinos, Peter

2012-08-01

Prehypertension is likely to progress to hypertension. The rate of progression is determined mostly by age and resting blood pressure but may also be attenuated by increased fitness. A graded exercise test was performed in 2303 men with prehypertension at the Veterans Affairs Medical Centers in Washington, DC. Four fitness categories were defined, based on peak metabolic equivalents (METs) achieved. We assessed the association between exercise capacity and rate of progression to hypertension (HTN). The median follow-up period was 7.8 years (mean (± SD) 9.2±6.1 years). The incidence rate of progression from prehypertension to hypertension was 34.4 per 1000 person-years. Exercise capacity was a strong and independent predictor of the rate of progression. Compared to the High-Fit individuals (>10.0 METs), the adjusted risk for developing HTN was 66% higher (hazard ratio, 1.66; 95% CI, 1.2 to 2.2; P=0.001) for the Low-Fit and, similarly, 72% higher (hazard ratio, 1.72; 95% CI, 1.2 to 2.3; P=0.001) for the Least-Fit individuals, whereas it was only 36% for the Moderate-Fit (hazard ratio, 1.36; 95% CI, 0.99 to 1.80; P=0.056). Significant predictors for the progression to HTN were also age (19% per 10 years), resting systolic blood pressure (16% per 10 mm Hg), body mass index (15.3% per 5 U), and type 2 diabetes mellitus (2-fold). In conclusion, an inverse, S-shaped association was shown between exercise capacity and the rate of progression from prehypertension to hypertension in middle-aged and older male veterans. The protective effects of fitness were evident when exercise capacity exceeded 8.5 METs. These findings emphasize the importance of fitness in the prevention of hypertension.

Quantifying the Role of Population Subdivision in Evolution on Rugged Fitness Landscapes

PubMed Central

Bitbol, Anne-Florence; Schwab, David J.

2014-01-01

Natural selection drives populations towards higher fitness, but crossing fitness valleys or plateaus may facilitate progress up a rugged fitness landscape involving epistasis. We investigate quantitatively the effect of subdividing an asexual population on the time it takes to cross a fitness valley or plateau. We focus on a generic and minimal model that includes only population subdivision into equivalent demes connected by global migration, and does not require significant size changes of the demes, environmental heterogeneity or specific geographic structure. We determine the optimal speedup of valley or plateau crossing that can be gained by subdivision, if the process is driven by the deme that crosses fastest. We show that isolated demes have to be in the sequential fixation regime for subdivision to significantly accelerate crossing. Using Markov chain theory, we obtain analytical expressions for the conditions under which optimal speedup is achieved: valley or plateau crossing by the subdivided population is then as fast as that of its fastest deme. We verify our analytical predictions through stochastic simulations. We demonstrate that subdivision can substantially accelerate the crossing of fitness valleys and plateaus in a wide range of parameters extending beyond the optimal window. We study the effect of varying the degree of subdivision of a population, and investigate the trade-off between the magnitude of the optimal speedup and the width of the parameter range over which it occurs. Our results, obtained for fitness valleys and plateaus, also hold for weakly beneficial intermediate mutations. Finally, we extend our work to the case of a population connected by migration to one or several smaller islands. Our results demonstrate that subdivision with migration alone can significantly accelerate the crossing of fitness valleys and plateaus, and shed light onto the quantitative conditions necessary for this to occur. PMID:25122220

Simplified method to solve sound transmission through structures lined with elastic porous material.

PubMed

Lee, J H; Kim, J

2001-11-01

An approximate analysis method is developed to calculate sound transmission through structures lined with porous material. Because the porous material has both the solid phase and fluid phase, three wave components exist in the material, which makes the related analysis very complicated. The main idea in developing the approximate method is very simple: modeling the porous material using only the strongest of the three waves, which in effect idealizes the material as an equivalent fluid. The analysis procedure has to be conducted in two steps. In the first step, sound transmission through a flat double panel with a porous liner of infinite extents, which has the same cross sectional construction as the actual structure, is solved based on the full theory and the strongest wave component is identified. In the second step sound transmission through the actual structure is solved modeling the porous material as an equivalent fluid while using the actual geometry of the structure. The development and validation of the method are discussed in detail. As an application example, the transmission loss through double walled cylindrical shells with a porous core is calculated utilizing the simplified method.

49 CFR 179.201-4 - Material.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.201-4 Material. All fittings...

Study on peak shape fitting method in radon progeny measurement.

PubMed

Yang, Jinmin; Zhang, Lei; Abdumomin, Kadir; Tang, Yushi; Guo, Qiuju

2015-11-01

Alpha spectrum measurement is one of the most important methods to measure radon progeny concentration in environment. However, the accuracy of this method is affected by the peak tailing due to the energy losses of alpha particles. This article presents a peak shape fitting method that can overcome the peak tailing problem in most situations. On a typical measured alpha spectrum curve, consecutive peaks overlap even their energies are not close to each other, and it is difficult to calculate the exact count of each peak. The peak shape fitting method uses combination of Gaussian and exponential functions, which can depict features of those peaks, to fit the measured curve. It can provide net counts of each peak explicitly, which was used in the Kerr method of calculation procedure for radon progeny concentration measurement. The results show that the fitting curve fits well with the measured curve, and the influence of the peak tailing is reduced. The method was further validated by the agreement between radon equilibrium equivalent concentration based on this method and the measured values of some commercial radon monitors, such as EQF3220 and WLx. In addition, this method improves the accuracy of individual radon progeny concentration measurement. Especially for the (218)Po peak, after eliminating the peak tailing influence, the calculated result of (218)Po concentration has been reduced by 21 %. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Maximum likelihood analysis of bioassay data from long-term follow-up of two refractory PuO2 inhalation cases.

PubMed

Avtandilashvili, Maia; Brey, Richard; James, Anthony C

2012-07-01

The U.S. Transuranium and Uranium Registries' tissue donors 0202 and 0407 are the two most highly exposed of the 18 registrants who were involved in the 1965 plutonium fire accident at a defense nuclear facility. Material released during the fire was well characterized as "high fired" refractory plutonium dioxide with 0.32-μm mass median diameter. The extensive bioassay data from long-term follow-up of these two cases were used to evaluate the applicability of the Human Respiratory Tract Model presented by International Commission on Radiological Protection in Publication 66 and its revision proposed by Gregoratto et al. in order to account for the observed long-term retention of insoluble material in the lungs. The maximum likelihood method was used to calculate the point estimates of intake and tissue doses and to examine the effect of different lung clearance, blood absorption, and systemic models on the goodness-of-fit and estimated dose values. With appropriate adjustments, Gregoratto et al. particle transport model coupled with the customized blood absorption parameters yielded a credible fit to the bioassay data for both cases and predicted the Case 0202 liver and skeletal activities measured postmortem. PuO2 particles produced by the plutonium fire are extremely insoluble. About 1% of this material is absorbed from the respiratory tract relatively rapidly, at a rate of about 1 to 2 d (half-time about 8 to 16 h). The remainder (99%) is absorbed extremely slowly, at a rate of about 5 × 10(-6) d (half-time about 400 y). When considering this situation, it appears that doses to other body organs are negligible in comparison to those to tissues of the respiratory tract. About 96% of the total committed weighted dose equivalent is contributed by the lungs. Doses absorbed by these workers' lungs were high: 3.2 Gy to AI and 6.5 Gy to LNTH for Case 0202 (18 y post-intake) and 3.2 Gy to AI and 55.5 Gy to LNTH for Case 0407 (43 y post-intake). This evaluation supports the Gregoratto et al. proposed revision to the ICRP 66 model when considering situations of extremely insoluble particles.

Equivalence in Dose Fall-Off for Isocentric and Nonisocentric Intracranial Treatment Modalities and Its Impact on Dose Fractionation Schemes

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

Ma Lijun, E-mail: lijunma@radonc.ucsf.ed; Sahgal, Arjun; Descovich, Martina

2010-03-01

Purpose: To investigate whether dose fall-off characteristics would be significantly different among intracranial radiosurgery modalities and the influence of these characteristics on fractionation schemes in terms of normal tissue sparing. Methods and Materials: An analytic model was developed to measure dose fall-off characteristics near the target independent of treatment modalities. Variations in the peripheral dose fall-off characteristics were then examined and compared for intracranial tumors treated with Gamma Knife, Cyberknife, or Novalis LINAC-based system. Equivalent uniform biologic effective dose (EUBED) for the normal brain tissue was calculated. Functional dependence of the normal brain EUBED on varying numbers of fractions (1more » to 30) was studied for the three modalities. Results: The derived model fitted remarkably well for all the cases (R{sup 2} > 0.99). No statistically significant differences in the dose fall-off relationships were found between the three modalities. Based on the extent of variations in the dose fall-off curves, normal brain EUBED was found to decrease with increasing number of fractions for the targets, with alpha/beta ranging from 10 to 20. This decrease was most pronounced for hypofractionated treatments with fewer than 10 fractions. Additionally, EUBED was found to increase slightly with increasing number of fractions for targets with alpha/beta ranging from 2 to 5. Conclusion: Nearly identical dose fall-off characteristics were found for the Gamma Knife, Cyberknife, and Novalis systems. Based on EUBED calculations, normal brain sparing was found to favor hypofractionated treatments for fast-growing tumors with alpha/beta ranging from 10 to 20 and single fraction treatment for abnormal tissues with low alpha/beta values such as alpha/beta = 2.« less

Magnetoencephalography recording and analysis.

PubMed

Velmurugan, Jayabal; Sinha, Sanjib; Satishchandra, Parthasarathy

2014-03-01

Magnetoencephalography (MEG) non-invasively measures the magnetic field generated due to the excitatory postsynaptic electrical activity of the apical dendritic pyramidal cells. Such a tiny magnetic field is measured with the help of the biomagnetometer sensors coupled with the Super Conducting Quantum Interference Device (SQUID) inside the magnetically shielded room (MSR). The subjects are usually screened for the presence of ferromagnetic materials, and then the head position indicator coils, electroencephalography (EEG) electrodes (if measured simultaneously), and fiducials are digitized using a 3D digitizer, which aids in movement correction and also in transferring the MEG data from the head coordinates to the device and voxel coordinates, thereby enabling more accurate co-registration and localization. MEG data pre-processing involves filtering the data for environmental and subject interferences, artefact identification, and rejection. Magnetic resonance Imaging (MRI) is processed for correction and identifying fiducials. After choosing and computing for the appropriate head models (spherical or realistic; boundary/finite element model), the interictal/ictal epileptiform discharges are selected and modeled by an appropriate source modeling technique (clinically and commonly used - single equivalent current dipole - ECD model). The equivalent current dipole (ECD) source localization of the modeled interictal epileptiform discharge (IED) is considered physiologically valid or acceptable based on waveform morphology, isofield pattern, and dipole parameters (localization, dipole moment, confidence volume, goodness of fit). Thus, MEG source localization can aid clinicians in sublobar localization, lateralization, and grid placement, by evoking the irritative/seizure onset zone. It also accurately localizes the eloquent cortex-like visual, language areas. MEG also aids in diagnosing and delineating multiple novel findings in other neuropsychiatric disorders, including Alzheimer's disease, Parkinsonism, Traumatic brain injury, autistic disorders, and so oon.

Quantitative analysis of Ni2+/Ni3+ in Li[NixMnyCoz]O2 cathode materials: Non-linear least-squares fitting of XPS spectra

NASA Astrophysics Data System (ADS)

Fu, Zewei; Hu, Juntao; Hu, Wenlong; Yang, Shiyu; Luo, Yunfeng

2018-05-01

Quantitative analysis of Ni2+/Ni3+ using X-ray photoelectron spectroscopy (XPS) is important for evaluating the crystal structure and electrochemical performance of Lithium-nickel-cobalt-manganese oxide (Li[NixMnyCoz]O2, NMC). However, quantitative analysis based on Gaussian/Lorentzian (G/L) peak fitting suffers from the challenges of reproducibility and effectiveness. In this study, the Ni2+ and Ni3+ standard samples and a series of NMC samples with different Ni doping levels were synthesized. The Ni2+/Ni3+ ratios in NMC were quantitatively analyzed by non-linear least-squares fitting (NLLSF). Two Ni 2p overall spectra of synthesized Li [Ni0.33Mn0.33Co0.33]O2(NMC111) and bulk LiNiO2 were used as the Ni2+ and Ni3+ reference standards. Compared to G/L peak fitting, the fitting parameters required no adjustment, meaning that the spectral fitting process was free from operator dependence and the reproducibility was improved. Comparison of residual standard deviation (STD) showed that the fitting quality of NLLSF was superior to that of G/L peaks fitting. Overall, these findings confirmed the reproducibility and effectiveness of the NLLSF method in XPS quantitative analysis of Ni2+/Ni3+ ratio in Li[NixMnyCoz]O2 cathode materials.

Marginal and internal fit of posterior three-unit fixed zirconia dental prostheses fabricated with two different CAD/CAM systems and materials.

PubMed

Schönberger, Joana; Erdelt, Kurt-Jürgen; Bäumer, Daniel; Beuer, Florian

2017-11-01

The purpose of this in vitro study was to compare the precision of fit of frameworks milled from semi-sintered regular zirconia and high-translucent (HT) zirconia blanks, fabricated with two different CAD/CAM systems. Three-unit, posterior fixed dental prostheses (FDP) frameworks were fabricated for standardized dies (n = 11) with two different laboratory computer-aided design (CAD)/computer-aided manufacturing (CAM) systems (Cercon/Ceramill). The replica technique was used to evaluate the marginal and internal fit under an optical microscope. Evaluation of the data was performed according to prior studies at a level of significance of 5%. The systems showed a statistically significant influence on the internal fit of the frameworks (p ≤ 0.001) and on the marginal fit (p < 0.001). The type of material showed no influence on the marginal fit for the Cercon system (p = 0.636) and on the marginal fit (p = 0.064) and the internal fit (p = 0.316) for the Ceramill system, while regular zirconia from Cercon showed higher internal values than HT zirconia (p = 0.016). Both investigated systems showed clinically acceptable values within the limitations of this in vitro study. However, one showed less internal accuracy when regular zirconia was used.

Non-detonable and non-explosive explosive simulators

DOEpatents

Simpson, Randall L.; Pruneda, Cesar O.

1997-01-01

A simulator which is chemically equivalent to an explosive, but is not detonable or explodable. The simulator is a combination of an explosive material with an inert material, either in a matrix or as a coating, where the explosive has a high surface ratio but small volume ratio. The simulator has particular use in the training of explosives detecting dogs, calibrating analytical instruments which are sensitive to either vapor or elemental composition, or other applications where the hazards associated with explosives is undesirable but where chemical and/or elemental equivalence is required. The explosive simulants may be fabricated by different techniques. A first method involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and a second method involves coating inert substrates with thin layers of explosive.

The cardiopulmonary exercise test grey zone; optimising fitness stratification by application of critical difference.

PubMed

Rose, G A; Davies, R G; Davison, G W; Adams, R A; Williams, I M; Lewis, M H; Appadurai, I R; Bailey, D M

2018-06-01

Cardiorespiratory fitness can inform patient care, although to what extent natural variation in CRF influences clinical practice remains to be established. We calculated natural variation for cardiopulmonary exercise test (CPET) metrics, which may have implications for fitness stratification. In a two-armed experiment, critical difference comprising analytical imprecision and biological variation was calculated for cardiorespiratory fitness and thus defined the magnitude of change required to claim a clinically meaningful change. This metric was retrospectively applied to 213 patients scheduled for colorectal surgery. These patients underwent CPET and the potential for misclassification of fitness was calculated. We created a model with boundaries inclusive of natural variation [critical difference applied to oxygen uptake at anaerobic threshold (V˙O 2 -AT): 11 ml O 2  kg -1  min -1 , peak oxygen uptake (V˙O 2 peak): 16 ml O 2  kg -1  min -1 , and ventilatory equivalent for carbon dioxide at AT (V̇ E /V̇CO 2 -AT): 36]. The critical difference for V˙O 2 -AT, V˙O 2 peak, and V˙ E /V˙CO 2 -AT was 19%, 13%, and 10%, respectively, resulting in false negative and false positive rates of up to 28% and 32% for unfit patients. Our model identified boundaries for unfit and fit patients: AT <9.2 and ≥13.6 ml O 2  kg -1  min -1 , V˙O 2 peak <14.2 and ≥18.3 ml kg -1  min -1 , V˙ E /V˙CO 2 -AT ≥40.1 and <32.7, between which an area of indeterminate-fitness was established. With natural variation considered, up to 60% of patients presented with indeterminate-fitness. These findings support a reappraisal of current clinical interpretation of cardiorespiratory fitness highlighting the potential for incorrect fitness stratification when natural variation is not accounted for. Copyright © 2018 British Journal of Anaesthesia. All rights reserved.

Dosimetric evaluation of Plastic Water Diagnostic-Therapy.

PubMed

Ramaseshan, Ramani; Kohli, Kirpal; Cao, Fred; Heaton, Robert K

2008-04-29

High-precision radiotherapy planning and quality assurance require accurate dosimetric and geometric phantom measurements. Phantom design requires materials with mechanical strength and resilience, and dosimetric properties close to those of water over diagnostic and therapeutic ranges. Plastic Water Diagnostic Therapy (PWDT: CIRS, Norfolk, VA) is a phantom material designed for water equivalence in photon beams from 0.04 MeV to 100 MeV; the material has also good mechanical properties. The present article reports the results of computed tomography (CT) imaging and dosimetric studies of PWDT to evaluate the suitability of the material in CT and therapy energy ranges. We characterized the water equivalence of PWDT in a series of experiments in which the basic dosimetric properties of the material were determined for photon energies of 80 kVp, 100 kVp, 250 kVp, 4 MV, 6 MV, 10 MV, and 18 MV. Measured properties included the buildup and percentage depth dose curves for several field sizes, and relative dose factors as a function of field size. In addition, the PWDT phantom underwent CT imaging at beam qualities ranging from 80 kVp to 140 kVp to determine the water equivalence of the phantom in the diagnostic energy range. The dosimetric quantities measured with PWDT agreed within 1.5% of those determined in water and Solid Water (Gammex rmi, Middleton, WI). Computed tomography imaging of the phantom was found to generate Hounsfield numbers within 0.8% of those generated using water. The results suggest that PWDT material is suitable both for regular radiotherapy quality assurance measurements and for intensity-modulated radiation therapy (IMRT) verification work. Sample IMRT verification results are presented.

Use of maxillofacial laboratory materials to construct a tissue-equivalent head phantom with removable titanium implantable devices for use in verification of the dose of intensity-modulated radiotherapy.

PubMed

Morris, K

2017-06-01

The dose of radiotherapy is often verified by measuring the dose of radiation at specific points within a phantom. The presence of high-density implant materials such as titanium, however, may cause complications both during calculation and delivery of the dose. Numerous studies have reported photon/electron backscatter and alteration of the dose by high-density implants, but we know of no evidence of a dosimetry phantom that incorporates high density implants or fixtures. The aim of the study was to design and manufacture a tissue-equivalent head phantom for use in verification of the dose in radiotherapy using a combination of traditional laboratory materials and techniques and 3-dimensional technology that can incorporate titanium maxillofacial devices. Digital designs were used together with Mimics® 18.0 (Materialise NV) and FreeForm® software. DICOM data were downloaded and manipulated into the final pieces of the phantom mould. Three-dimensional digital objects were converted into STL files and exported for additional stereolithography. Phantoms were constructed in four stages: material testing and selection, design of a 3-dimensional mould, manufacture of implants, and final fabrication of the phantom using traditional laboratory techniques. Three tissue-equivalent materials were found and used to successfully manufacture a suitable phantom with interchangeable sections that contained three versions of titanium maxillofacial implants. Maxillofacial and other materials can be used to successfully construct a head phantom with interchangeable titanium implant sections for use in verification of doses of radiotherapy. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

TH-AB-209-02: Gadolinium Measurements in Human Bone Using in Vivo K X-Ray Fluorescence (KXRF) Technique

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

Mostafaei, F; Nie, L

Purpose: Improvement in an in vivo K x-ray fluorescence system, based on 109Cd source, for the detection of gadolinium (Gd) in bone has been investigated. Series of improvements to the method is described. Gd is of interest because of the extensive use of Gd-based contrast agents in MR imaging and the potential toxicity of Gd exposure. Methods: A set of seven bone equivalent phantoms with different amount of Gd concentrations (from 0–100 ppm) has been developed. Soft tissue equivalent plastic plates were used to simulate the soft tissue overlaying the tibia bone in an in vivo measurement. A new 5more » GBq 109Cd source was used to improve the source activity in comparison to the previous study (0.17 GBq). An improved spectral fitting program was utilized for data analysis. Results: The previous published minimum detection limit (MDL) for Gd doped phantom measurements using KXRF system was 3.3 ppm. In this study the MDL for bare bone phantoms was found to be 0.8 ppm. Our previous study used only three layers of plastic (0.32, 0.64 and 0.96 mm) as soft tissue equivalent materials and obtained the MDL of 4–4.8 ppm. In this study the plastic plates with more realistic thicknesses to simulate the soft tissue covering tibia bone (nine thicknesses ranging from 0.61–6.13 mm) were used. The MDLs for phantoms were determined to be 1.8–3.5 ppm. Conclusion: With the improvements made to the technology (stronger source, improved data analysis algorithm, realistic soft tissue thicknesses), the MDL of the KXRF system to measure Gd in bare bone was improved by a factor of 4.1. The MDL is at the level of the bone Gd concentration reported in literature. Hence, the system is ready to be tested on human subjects to investigate the use of bone Gd as a biomarker for Gd toxicity.« less

Dielectric relaxation in AC powder electroluminescent devices

NASA Astrophysics Data System (ADS)

Zhang, Shuai; Su, Haibin; Tan, Chuan Seng; Wong, Terence Kin Shun; Teo, Ronnie Jin Wah

2017-01-01

The dielectric properties of AC powder electroluminescent devices were measured and analyzed using complex impedance spectroscopy to determine the relaxation processes occurring within the devices. The relaxation processes identified were ascribed to the electrode polarization caused by ion accumulation at the electrode/resin interfaces, the Maxwell-Wagner-Sillars effects at the (ZnS or BaTiO3) particle/resin interfaces, and the dipolar reorientation of polymer chains in the resin matrix. Each relaxation process was represented by its corresponding equivalent circuit component. Space charge polarization at the electrodes were represented by a Warburg element, a resistor, and a constant phase element. The resin matrix, ZnS/resin and BaTiO3/resin interfaces could each be modeled by a resistor and a capacitor in parallel. The simulated equivalent circuits for three different printed structures showed good fitting with their experimental impedance results.

The Strengths and Difficulties Questionnaire (SDQ): Factor Structure and Gender Equivalence in Norwegian Adolescents

PubMed Central

Hysing, Mari; Skogen, Jens Christoffer; Breivik, Kyrre

2016-01-01

Although frequently used with older adolescents, few studies of the factor structure, internal consistency and gender equivalence of the SDQ exists for this age group, with inconsistent findings. In the present study, confirmatory factor analysis (CFA) was used to evaluate the five-factor structure of the SDQ in a population sample of 10,254 16–18 year-olds from the youth@hordaland study. Measurement invariance across gender was assessed using multigroup CFA. A modestly modified five-factor solution fitted the data acceptably, accounting for one cross loading and some local dependencies. Importantly, partial measurement non-invariance was identified, with differential item functioning in eight items, and higher correlations between emotional and conduct problems for boys compared to girls. Implications for use clinically and in research are discussed. PMID:27138259

MCNP modelling of the wall effects observed in tissue-equivalent proportional counters.

PubMed

Hoff, J L; Townsend, L W

2002-01-01

Tissue-equivalent proportional counters (TEPCs) utilise tissue-equivalent materials to depict homogeneous microscopic volumes of human tissue. Although both the walls and gas simulate the same medium, they respond to radiation differently. Density differences between the two materials cause distortions, or wall effects, in measurements, with the most dominant effect caused by delta rays. This study uses a Monte Carlo transport code, MCNP, to simulate the transport of secondary electrons within a TEPC. The Rudd model, a singly differential cross section with no dependence on electron direction, is used to describe the energy spectrum obtained by the impact of two iron beams on water. Based on the models used in this study, a wall-less TEPC had a higher lineal energy (keV.micron-1) as a function of impact parameter than a solid-wall TEPC for the iron beams under consideration. An important conclusion of this study is that MCNP has the ability to model the wall effects observed in TEPCs.

78 FR 1101 - Hazardous Materials: Harmonization With the United Nations Recommendations on the Transport of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-07

... packaging maintains an equivalent level of performance to the originally tested packaging design must be... material, packing group assignments, special provisions, packaging authorizations, packaging sections, air... responsibilities related to packaging design variation, manufacturer notification, and recordkeeping requirements...

Radiopacity of different resin-based and conventional luting cements compared to human and bovine teeth.

PubMed

Pekkan, Gürel; Ozcan, Mutlu

2012-02-03

This study evaluated the radiopacity of different resin-based luting materials and compared the results to human and bovine dental hard tissues. Disc specimens (N=130, n=10 per group) (diameter: 6 mm, thickness: 1 mm) were prepared from 10 resin-based and 3 conventional luting cements. Human canine dentin (n=10), bovine enamel (n=10), bovine dentin (n=10) and Aluminium (Al) step wedge were used as references. The optical density values of each material were measured from radiographic images using a transmission densitometer. Al step wedge thickness and optical density values were plotted and equivalent Al thickness values were determined for radiopacity measurements of each material. The radiopacity values of conventional cements and two resin luting materials (Rely X Unicem and Variolink II), were significantly higher than that of bovine enamel that could be preferred for restorations cemented on enamel. Since all examined resin-based luting materials showed radiopacity values equivalent to or greater than that of human and bovine dentin, they could be considered suitable for the restorations cemented on dentin.

Space Environmental Effects on the Optical Properties of Selected Transparent Polymers

NASA Technical Reports Server (NTRS)

Edwards, David L.; Willowby, Douglas J.; Hubbs, Whitney C.; Piszczor, Michael F., Jr.; Bowden, Mary L.

1997-01-01

Transparent polymer films are currently considered for use as solar concentrating lenses for spacecraft power and propulsion systems. These polymer films concentrate solar energy onto energy conversion devices such as solar cells and thermal energy systems. Conversion efficiency is directly related to the polymer transmission. Space environmental effects will decrease the transmission and thus reduce the conversion efficiency. This investigation focuses on the effects of ultraviolet and charged particle radiation on the transmission of selected transparent polymers. Multiple candidate polymer samples were exposed to near ultraviolet (NUV) radiation to screen the materials and select optimum materials for further study. All materials experienced transmission degradation of varying degree. A method was developed to normalize the transmission loss and thus rank the materials according to their tolerance of NUV. Teflon(Tm) FEP and Teflon(Tm) PFA were selected for further study. These materials were subjected to a combined charged particle dose equivalent to 5 years in a typical geosynchronous Earth orbit (GEO). Results from these NUV screening tests and the 5 year GEO equivalent dose are presented.

Method of Characteristics Calculations and Computer Code for Materials with Arbitrary Equations of State and Using Orthogonal Polynomial Least Square Surface Fits

NASA Technical Reports Server (NTRS)

Chang, T. S.

1974-01-01

A numerical scheme using the method of characteristics to calculate the flow properties and pressures behind decaying shock waves for materials under hypervelocity impact is developed. Time-consuming double interpolation subroutines are replaced by a technique based on orthogonal polynomial least square surface fits. Typical calculated results are given and compared with the double interpolation results. The complete computer program is included.

Radiopacity of Composite Luting Cements Using a Digital Technique.

PubMed

Dukic, Walter

2017-01-10

The aim of this in vitro study was to evaluate the radiopacity of 20 common dental composite luting materials using a digital technique. A 1-mm-thick specimen of each material with a human tooth slice and aluminium step wedge were tested using digital radiographs under four combinations of exposure and voltage. The radiopacity in pixels was determined using computer software. The equivalent thickness of aluminium for each material was then calculated based on the calibration curve. All tested materials except one had higher radiopacity than dentin (p > α; α  =  0.01), and 80% of the materials had radiopacity above enamel value (p > α; α  =  0.01). Moreover, 40% of tested materials had radiopacity of three times above the minimal International Organization for Standardization (ISO) values for composite luting cements. At all exposure values, the highest radiopacity was for Solocem and Multilink groups of materials, at three to six times above dentin radiopacity. Only Variolink Veneer showed radiopacity below dentin and enamel. Composite luting materials should have radiopacity above ISO values or greater than the dentin or enamel equivalent. The highest radiopacity values were for the Solocem and Multilink family composite luting cements. Clinicians should choose materials with high radiopacity values, and manufacturers should be aware of the radiopacity values when introducing materials on the market. © 2017 by the American College of Prosthodontists.

Radiopacity of flowable composite by a digital technique.

PubMed

Dukić, W; Delija, B; Lešić, S; Dubravica, I; Derossi, D

2013-01-01

The aim of this in vitro study was to evaluate the radiopacity of 19 current dental flowable composite materials by a digital technique. Digital radiographs were obtained with a CCD sensor using an aluminum step wedge, a 1-mm-thick tooth slice, and a 1-mm-thick flowable composite specimen using five different combinations of exposure and voltage. The radiopacity in pixels was determined using Digora 2.6. software. The equivalent thickness of aluminum for each material was then calculated based on the calibration curve. All of the tested flowable composite materials had higher radiopacities than that of dentin, but in almost every combination of exposure and voltage, there were some composite materials that exhibited radiopacities equal to or slightly greater than enamel p>α; α=0.01). Of the flowable composite materials tested, 37% showed lower radiopacities than enamel, and 21% of the tested materials had higher radiopacities than the 3-mm aluminum equivalent. The highest radiopacity at all exposure values was produced by the Majesty Flow and Charisma Opal Flow materials, which had radiopacities almost twice that of enamel. Flowable composite materials should have radiopacities greater than that of enamel (ISO 4049), an important consideration for the introduction of new materials to the market. The digital radiopacity analysis techniques used in this study provide an easy, reliable, rapid, and precise method to characterize radiopacity of dental flowable composite materials.

Adsorption-Coupled Diffusion of Gold Nanoclusters within a Large-Pore Protein Crystal Scaffold.

PubMed

Hartje, Luke F; Munsky, Brian; Ni, Thomas W; Ackerson, Christopher J; Snow, Christopher D

2017-08-17

Large-pore protein crystals (LPCs) are ordered biologically derived nanoporous materials exhibiting pore diameters greater than 8 nm. These substantial pores distinguish LPCs from typical nanoporous scaffolds, enabling engineered LPC materials to readily uptake, immobilize, and release macromolecular guests. In this study, macromolecular transport within an LPC environment was experimentally and computationally investigated by studying adsorption-coupled diffusion of Au 25 (glutathione) 18 nanoclusters within a cross-linked LPC scaffold via time-lapse confocal microscopy, bulk equilibrium adsorption, and hindered diffusion simulation. Equilibrium adsorption data is congruent with a Langmuir adsorption model, exhibiting strong binding behavior between nanoclusters and the scaffold. The standard Gibbs free energy of binding is equivalent to -37.2 kJ/mol, and the maximum binding capacity of 1.25 × 10 3 mg/g corresponds to approximately 29 nanoclusters per LPC unit cell. The hindered diffusion model showed good agreement with experimental data, revealing a pore diffusion coefficient of 3.7 × 10 -7 cm 2 /s under low nanocluster concentration. Furthermore, the model was sufficient to determine adsorption and desorption kinetic values for k a and k d equal to 13 cm 3 /mol·s and 1.7 × 10 -7 s -1 , respectively. At higher nanocluster concentrations, the simulated pore diffusion coefficient could be reduced by 3 orders of magnitude to 3.4 × 10 -10 cm 2 /s due to the effects of pore occlusion. This study demonstrates a strategy to analyze adsorption-coupled diffusion data to better understand complex transport of fluorescent macromolecules into LPCs. This approach fits the observable fluorescence data to the key molecular details and will benefit downstream efforts to engineer LPC-based nanoporous materials.

Preliminary study of silica aerogel as a gas-equivalent material in ionization chambers

NASA Astrophysics Data System (ADS)

Caresana, M.; Zorloni, G.

2017-12-01

Since about two decades, a renewed interest on aerogels has risen. These peculiar materials show fairly unique properties. Thus, they are under investigation for both scientific and commercial purposes and new optimized production processes are studied. In this work, the possibility of using aerogel in the field of radiation detection is explored. The idea is to substitute the gas filling in a ionization chamber with the aerogel. The material possesses a density about 100 times greater than ambient pressure air. Where as the open-pore structure should allow the charge carriers to move freely. Small hydrophobic silica aerogel samples were studied. A custom ionization chamber, capable of working both with aerogel or in the classic gas set up, was built. The response of the chamber in current mode was investigated using an X-ray tube. The results obtained showed, under proper conditions, an enhancement of about 60 times of the current signal in the aerogel configuration with respect to the classic gas one. Moreover, some unusual behaviours were observed, i.e. time inertia of the signal and super-/sub-linear current response with respect to the dose rate. While testing high electric fields, aerogel configuration seemed to enhance the Townsend's effects. In order to represent the observed trends, a trapping-detrapping model is proposed, which is capable to predict semi-empirically the steady state currents measured. The time evolution of the signal is semi-quantitatively represented by the same model. The coefficients estimated by the fits are in agreement with similar trapping problems in the literature. In particular, a direct comparison between the benchmark of the FET silica gates and aerogel case endorses the idea that the same type of phenomenon occurs in the studied case.

Recovery of slaughterhouse Animal Fatty Wastewater Sludge by conversion into Fatty Acid Butyl Esters by acid-catalyzed esterification.

PubMed

Wallis, Christopher; Cerny, Muriel; Lacroux, Eric; Mouloungui, Zéphirin

2017-02-01

Two types of Animal Fatty Wastewater Sludges (AFWS 1 and 2) were analyzed and fully characterized to determine their suitability for conversion into biofuel. AFWS 1 was determined to be unsuitable as it contains 68.8wt.% water and only 32.3wt.% dry material, of which only around 80% is lipids to be converted. AFWS 2 has only 15.7wt.% water and 84.3wt.% dry material of which is assumed to 100% lipids as the protein and ash contents were determined to be negligible. The 4-dodecylbenzenesulfonic acid (DBSA) catalyzed esterification of AFWS with 1-butanol was performed in a novel batch reactor fitted with a drying chimney for the "in situ" removal of water and optimized using a non-conventional Doehlert surface response methodology. The optimized condition was found to be 1.66mol equivalent of 1-butanol (with respect to total fatty acid chains), 10wt.% of DBSA catalyst (with respect to AFWS) at 105°C for 3h. Fatty Acid Butyl Esters (FABEs) were isolated in good yields (95%+) as well as a blend of FABEs with 1-butanol (16%). The two potential biofuels were analyzed in comparison with current and analogous biofuels (FAME based biodiesel, and FABE products made from vegetable oils) and were found to exhibit high cetane numbers and flash point values. Copyright © 2016 Elsevier Ltd. All rights reserved.

Insight into collision zone dynamics from topography: numerical modelling results and observations

NASA Astrophysics Data System (ADS)

Bottrill, A. D.; van Hunen, J.; Allen, M. B.

2012-07-01

Dynamic models of subduction and continental collision are used to predict dynamic topography changes on the overriding plate. The modelling results show a distinct evolution of topography on the overriding plate, during subduction, continental collision and slab break-off. A prominent topographic feature is a temporary (few Myrs) deepening in the area of the back arc-basin after initial collision. This collisional mantle dynamic basin (CMDB) is caused by slab steepening drawing material away from the base of the overriding plate. Also during this initial collision phase, surface uplift is predicted on the overriding plate between the suture zone and the CMDB, due to the subduction of buoyant continental material and its isostatic compensation. After slab detachment, redistribution of stresses and underplating of the overriding plate causes the uplift to spread further into the overriding plate. This topographic evolution fits the stratigraphy found on the overriding plate of the Arabia-Eurasia collision zone in Iran and south east Turkey. The sedimentary record from the overriding plate contains Upper Oligocene-Lower Miocene marine carbonates deposited between terrestrial clastic sedimentary rocks, in units such as the Qom Formation and its lateral equivalents. This stratigraphy shows that during the Late Oligocene-Early Miocene the surface of the overriding plate sank below sea level before rising back above sea level, without major compressional deformation recorded in the same area. This uplift and subsidence pattern correlates well with our modelled topography changes.

Space Radiation Dosimetry to Evaluate the Effect of Polyethylene Shielding in the Russian Segment of the International Space Station

NASA Astrophysics Data System (ADS)

Nagamatsu, Aiko; Casolino, Marco; Larsson, Oscar; Ito, Tsuyoshi; Yasuda, Nakahiro; Kitajo, Keiichi; Shimada, Ken; Takeda, Kazuo; Tsuda, Shuichi; Sato, Tatsuhiko

As a part of the Alteino Long Term Cosmic Ray measurements on board the International Space Station (ALTCRISS) project, the shielding effect of polyethylene (PE) were evaluated in the Russian segment of the ISS, using active and passive dosimeter systems covered with or without PE shielding. For the passive dosimeter system, PADLES (Passive Dosimeter for Life-Science and Experiments in Space) was used in the project, which consists of a Thermo-Luminescent Dosimeters (TLD) and CR-39 Plastic Nuclear Track Detectors (PNTDs) attached to a radiator. Not only CR-39 PNTD itself but also a tissue equivalent material, NAN-JAERI, were employed as the radiator in order to investigate whether CR-39 PNTD can be used as a surrogate of tissue equivalent material in space dosimetry or not. The agreements between the doses measured by PADLES with CR-39 PNTD and NAN-JAERI radiators were quite satisfactorily, indicating the tissue-equivalent dose can be measured by conventional PADLES even though CR-39 PNTD is not perfect tissue-equivalent material. It was found that the shielding effect of PE varies with location inside the spacecraft: it became less significant with an increase of the mean thickness of the wall. This tendency was also verified by Monte Carlo simulation using the PHITS code. Throughout the flight experiments, in a series of four phases in the ALTCRISS project from December 2005 to October 2007, we assessed the ability of PE to decrease radiation doses in Low Earth Orbit(LEO).

Whole of Government Approach to Transnational Organized Crime: Where and How Does the Military Fit In?

DTIC Science & Technology

2015-06-12

justice. The below articles of Title VII address the issues involved in combatting crime: 49 ARTICLE 89 Money laundering and financing of...mechanisms to combat money laundering and financing of terrorism equivalent to those adopted by the EU and other international fora in this field, in...tools to recover assets stolen by corrupt officials and make it harder for criminals to hide, launder , and benefit from illegal proceeds. Our

Distribution of fixed beneficial mutations and the rate of adaptation in asexual populations

PubMed Central

Good, Benjamin H.; Rouzine, Igor M.; Balick, Daniel J.; Hallatschek, Oskar; Desai, Michael M.

2012-01-01

When large asexual populations adapt, competition between simultaneously segregating mutations slows the rate of adaptation and restricts the set of mutations that eventually fix. This phenomenon of interference arises from competition between mutations of different strengths as well as competition between mutations that arise on different fitness backgrounds. Previous work has explored each of these effects in isolation, but the way they combine to influence the dynamics of adaptation remains largely unknown. Here, we describe a theoretical model to treat both aspects of interference in large populations. We calculate the rate of adaptation and the distribution of fixed mutational effects accumulated by the population. We focus particular attention on the case when the effects of beneficial mutations are exponentially distributed, as well as on a more general class of exponential-like distributions. In both cases, we show that the rate of adaptation and the influence of genetic background on the fixation of new mutants is equivalent to an effective model with a single selection coefficient and rescaled mutation rate, and we explicitly calculate these effective parameters. We find that the effective selection coefficient exactly coincides with the most common fixed mutational effect. This equivalence leads to an intuitive picture of the relative importance of different types of interference effects, which can shift dramatically as a function of the population size, mutation rate, and the underlying distribution of fitness effects. PMID:22371564

Trimming algorithm of frequency modulation for CIAE-230 MeV proton superconducting synchrocyclotron model cavity

NASA Astrophysics Data System (ADS)

Li, Pengzhan; Zhang, Tianjue; Ji, Bin; Hou, Shigang; Guo, Juanjuan; Yin, Meng; Xing, Jiansheng; Lv, Yinlong; Guan, Fengping; Lin, Jun

2017-01-01

A new project, the 230 MeV proton superconducting synchrocyclotron for cancer therapy, was proposed at CIAE in 2013. A model cavity is designed to verify the frequency modulation trimming algorithm featuring a half-wave structure and eight sets of rotating blades for 1 kHz frequency modulation. Based on the electromagnetic (EM) field distribution analysis of the model cavity, the variable capacitor works as a function of time and the frequency can be written in Maclaurin series. Curve fitting is applied for theoretical frequency and original simulation frequency. The second-order fitting excels at the approximation given its minimum variance. Constant equivalent inductance is considered as an important condition in the calculation. The equivalent parameters of theoretical frequency can be achieved through this conversion. Then the trimming formula for rotor blade outer radius is found by discretization in time domain. Simulation verification has been performed and the results show that the calculation radius with minus 0.012 m yields an acceptable result. The trimming amendment in the time range of 0.328-0.4 ms helps to reduce the frequency error to 0.69% in Simulation C with an increment of 0.075 mm/0.001 ms, which is half of the error in Simulation A (constant radius in 0.328-0.4 ms). The verification confirms the feasibility of the trimming algorithm for synchrocyclotron frequency modulation.

The ambient dose equivalent at flight altitudes: a fit to a large set of data using a Bayesian approach.

PubMed

Wissmann, F; Reginatto, M; Möller, T

2010-09-01

The problem of finding a simple, generally applicable description of worldwide measured ambient dose equivalent rates at aviation altitudes between 8 and 12 km is difficult to solve due to the large variety of functional forms and parametrisations that are possible. We present an approach that uses Bayesian statistics and Monte Carlo methods to fit mathematical models to a large set of data and to compare the different models. About 2500 data points measured in the periods 1997-1999 and 2003-2006 were used. Since the data cover wide ranges of barometric altitude, vertical cut-off rigidity and phases in the solar cycle 23, we developed functions which depend on these three variables. Whereas the dependence on the vertical cut-off rigidity is described by an exponential, the dependences on barometric altitude and solar activity may be approximated by linear functions in the ranges under consideration. Therefore, a simple Taylor expansion was used to define different models and to investigate the relevance of the different expansion coefficients. With the method presented here, it is possible to obtain probability distributions for each expansion coefficient and thus to extract reliable uncertainties even for the dose rate evaluated. The resulting function agrees well with new measurements made at fixed geographic positions and during long haul flights covering a wide range of latitudes.

A cross-sectional study of cardiorespiratory fitness and gallbladder disease.

PubMed

Li, Changqing; Mikus, Catherine; Ahmed, Ali; Hu, Gang; Xiong, Kaiyu; Zhang, Yimin; Sui, Xuemei

2017-04-01

To determine the association of different levels of cardiorespiratory fitness (CRF), an objective indicator of habitual physical activity, with gallbladder disease. In the Aerobics Center Longitudinal Study (ACLS) database, 41,528 men and 13,206 women aged 20-90 years, with body mass index of 18.5 or more and without history of cardiovascular disease and cancer, received a preventive examination at the Cooper Clinic in Dallas, Texas, between 1970 and 2003. CRF was quantified as maximal metabolic equivalents and classified as low, moderate, and high based on traditional ACLS cut points. Gallbladder disease was defined as physician-diagnosed gallbladder disease. When compared with low CRF, adjusted odds ratios and 95% confidence intervals for gallbladder disease for those with moderate and high CRF were 0.74 (0.55-0.99) and 0.59 (0.42-0.82), respectively when adjusted for all the potential confounders. Each one metabolic equivalent increment of CRF was associated with 10% lower odds of gallbladder disease in all participants (P for trend <.001), 13% lower in women (P for trend <.001), and 8% lower in men (P for trend = .08). The association was consistent across age, history of diabetes mellitus, and physical inactivity subgroups. CRF is inversely related to the prevalence of gallbladder disease among relatively healthy men and women in the ACLS cohort. Copyright © 2016 Elsevier Inc. All rights reserved.

Cross-Cultural Adaptation and Psychometric Testing of the Brazilian Version of the Self-Care of Heart Failure Index Version 6.2

PubMed Central

Ávila, Christiane Wahast; Riegel, Barbara; Pokorski, Simoni Chiarelli; Camey, Suzi; Silveira, Luana Claudia Jacoby; Rabelo-Silva, Eneida Rejane

2013-01-01

Objective. To adapt and evaluate the psychometric properties of the Brazilian version of the SCHFI v 6.2. Methods. With the approval of the original author, we conducted a complete cross-cultural adaptation of the instrument (translation, synthesis, back translation, synthesis of back translation, expert committee review, and pretesting). The adapted version was named Brazilian version of the self-care of heart failure index v 6.2. The psychometric properties assessed were face validity and content validity (by expert committee review), construct validity (convergent validity and confirmatory factor analysis), and reliability. Results. Face validity and content validity were indicative of semantic, idiomatic, experimental, and conceptual equivalence. Convergent validity was demonstrated by a significant though moderate correlation (r = −0.51) on comparison with equivalent question scores of the previously validated Brazilian European heart failure self-care behavior scale. Confirmatory factor analysis supported the original three-factor model as having the best fit, although similar results were obtained for inadequate fit indices. The reliability of the instrument, as expressed by Cronbach's alpha, was 0.40, 0.82, and 0.93 for the self-care maintenance, self-care management, and self-care confidence scales, respectively. Conclusion. The SCHFI v 6.2 was successfully adapted for use in Brazil. Nevertheless, further studies should be carried out to improve its psychometric properties. PMID:24163765

Refractive indices measurement of (GaInP)m/(AlInP)n quasi-quanternaries and GaInP/AllnP multiple quantum wells

NASA Astrophysics Data System (ADS)

Kaneko, Yawara; Kishino, Katsumi

1994-08-01

Measurements of the refractive indices of (GaInP)m/(AlInP)n quasi-quaternaries (QQs), GaInP/AlInP multiple quantum wells (MQWs), and (Al(x)Ga(1 - x))(0.5) In(0.5)P quanternaries were made systematically, using the reflectance method, in photon energy ranges nearly as high as up to the band gap. Data was fitted using the modified single effective oscillator (MSEO) method. A single oscillator energy E(sub zero) of 4.17 + 0.49 x(sub eg) and dispersion energy (E(sub d) of 35.79 - 1.16 x(sub eg) was obtained for (GaInP)m/(AlInP)2 QQs, where the equivalent Al composition x(sub eg) is defined by the stacking film thickness ratio x(sub eg) = d(AlInP)/(d(GaInP) + d(AlInP). Agreement of refractive indices obtained for QQs and quaternary compounds with equivalent x(sub eg) has been confirmed. Still, for the GaInP/AlInP MQWs, MSEO fitting was also agreeable, using the same oscillator energy E(sub zero) and dispersion energy E(sub d) of the (GaInP)m/(AlInP)2 QQs with the same thickness ratio, and substituting band gap energy E(sub Gamma) values shifted due to quantum effects.

Induction of Micronuclei in Human Fibroblasts from the Los Alamos High Energy Neutron Beam

NASA Technical Reports Server (NTRS)

Cox, Bradley

2009-01-01

The space radiation field includes a broad spectrum of high energy neutrons. Interactions between these neutrons and a spacecraft, or other material, significantly contribute to the dose equivalent for astronauts. The 15 degree beam line in the Weapons Neutron Research beam at Los Alamos Nuclear Science Center generates a neutron spectrum relatively similar to that seen in space. Human foreskin fibroblast (AG1522) samples were irradiated behind 0 to 20 cm of water equivalent shielding. The cells were exposed to either a 0.05 or 0.2 Gy entrance dose. Following irradiation, micronuclei were counted to see how the water shield affects the beam and its damage to cell nuclei. Micronuclei induction was then compared with dose equivalent data provided from a tissue equivalent proportional counter.

Geometric flow control of shear bands by suppression of viscous sliding

PubMed Central

Viswanathan, Koushik; Mahato, Anirban; Sundaram, Narayan K.; M'Saoubi, Rachid; Trumble, Kevin P.; Chandrasekar, Srinivasan

2016-01-01

Shear banding is a plastic flow instability with highly undesirable consequences for metals processing. While band characteristics have been well studied, general methods to control shear bands are presently lacking. Here, we use high-speed imaging and micro-marker analysis of flow in cutting to reveal the common fundamental mechanism underlying shear banding in metals. The flow unfolds in two distinct phases: an initiation phase followed by a viscous sliding phase in which most of the straining occurs. We show that the second sliding phase is well described by a simple model of two identical fluids being sheared across their interface. The equivalent shear band viscosity computed by fitting the model to experimental displacement profiles is very close in value to typical liquid metal viscosities. The observation of similar displacement profiles across different metals shows that specific microstructure details do not affect the second phase. This also suggests that the principal role of the initiation phase is to generate a weak interface that is susceptible to localized deformation. Importantly, by constraining the sliding phase, we demonstrate a material-agnostic method—passive geometric flow control—that effects complete band suppression in systems which otherwise fail via shear banding. PMID:27616920

Geometric flow control of shear bands by suppression of viscous sliding

NASA Astrophysics Data System (ADS)

Sagapuram, Dinakar; Viswanathan, Koushik; Mahato, Anirban; Sundaram, Narayan K.; M'Saoubi, Rachid; Trumble, Kevin P.; Chandrasekar, Srinivasan

2016-08-01

Shear banding is a plastic flow instability with highly undesirable consequences for metals processing. While band characteristics have been well studied, general methods to control shear bands are presently lacking. Here, we use high-speed imaging and micro-marker analysis of flow in cutting to reveal the common fundamental mechanism underlying shear banding in metals. The flow unfolds in two distinct phases: an initiation phase followed by a viscous sliding phase in which most of the straining occurs. We show that the second sliding phase is well described by a simple model of two identical fluids being sheared across their interface. The equivalent shear band viscosity computed by fitting the model to experimental displacement profiles is very close in value to typical liquid metal viscosities. The observation of similar displacement profiles across different metals shows that specific microstructure details do not affect the second phase. This also suggests that the principal role of the initiation phase is to generate a weak interface that is susceptible to localized deformation. Importantly, by constraining the sliding phase, we demonstrate a material-agnostic method-passive geometric flow control-that effects complete band suppression in systems which otherwise fail via shear banding.

Electron Spin Resonance Dating of Toxodon Tooth from Upper Ribeira Valley, São Paulo, Brazil.

PubMed

Kinoshita, Angela; Ghilardi, Aline Marcele; Fernandes, Marcelo Adorna; Figueiredo, Ana Maria G; Baffa, Oswaldo

2016-12-01

Electron spin resonance (ESR) dating was applied to date a sample of fossil tooth found in Ribeira Valley, São Paulo, Brazil. This region is characterized by abundant fossil records of Pleistocene-Holocene South American megafauna belonging to different faunistic moments related to climate changes during the quaternary. As the number of fossils dated is not too large, the dating of materials from this region will provide important information to better understand the events associated with the presence and extinction of these species. The equivalent dose (D e ) was determined using single exponential fitting resulting in (24 ± 1)Gy. The D e was converted to age using ROSY ESR Dating program and the concentration of radioisotopes present in the sample and soil determined through neutron activation analysis. The ages cover the range of 25-34 ka. This information is important to contextualize other findings in the region from different sites and to help obtain better information about the climate changes in this region. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Characterization and reconstruction of 3D stochastic microstructures via supervised learning.

PubMed

Bostanabad, R; Chen, W; Apley, D W

2016-12-01

The need for computational characterization and reconstruction of volumetric maps of stochastic microstructures for understanding the role of material structure in the processing-structure-property chain has been highlighted in the literature. Recently, a promising characterization and reconstruction approach has been developed where the essential idea is to convert the digitized microstructure image into an appropriate training dataset to learn the stochastic nature of the morphology by fitting a supervised learning model to the dataset. This compact model can subsequently be used to efficiently reconstruct as many statistically equivalent microstructure samples as desired. The goal of this paper is to build upon the developed approach in three major directions by: (1) extending the approach to characterize 3D stochastic microstructures and efficiently reconstruct 3D samples, (2) improving the performance of the approach by incorporating user-defined predictors into the supervised learning model, and (3) addressing potential computational issues by introducing a reduced model which can perform as effectively as the full model. We test the extended approach on three examples and show that the spatial dependencies, as evaluated via various measures, are well preserved in the reconstructed samples. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

A fitness-for-purpose evaluation of fracture critical electro-slag welds.

DOT National Transportation Integrated Search

2009-03-01

A fitness-for-purpose evaluation was performed on the electro-slag flange welds of the West Fremont bridge approach : superstructures, per the request of FHWA. This evaluation required gathering knowledge of the material properties, fabrication : def...

Ignition delay of combustible materials in normoxic equivalent environments

Treesearch

Sara McAllister; Carlos Fernandez-Pello; Gary Ruff; David Urban

2009-01-01

Material flammability is an important factor in determining the pressure and composition (fraction of oxygen and nitrogen) of the atmosphere in the habitable volume of exploration vehicles and habitats. The method chosen in this work to quantify the flammability of a material is by its ease of ignition. The ignition delay time was defined as the time it takes a...

SU-G-IeP2-12: The Effect of Iterative Reconstruction and CT Tube Voltage On Hounsfield Unit Values of Iodinated Contrast

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

Ogden, K; Greene-Donnelly, K; Vallabhaneni, D

Purpose: To investigate the effects of changing iterative reconstruction strength and tube voltage on Hounsfield Unit (HU) values of varying concentrations of Iodinated contrast medium in a phantom. Method: Iodinated contrast (Omnipaque 300, GE Healthcare, Princeton NJ) was diluted with distilled water to concentrations of 0.6, 0.9, 1.8, 3.6, 7.2, and 10.8 mg/mL of Iodine. The solutions were scanned in a patient equivalent water phantom on two MDCT scanners: VCT 64 slice (GE Medical Systems, Waukesha, WI) and an Aquilion One 320 slice scanner (Toshiba America Medical Systems, Tustin CA). The phantom was scanned at 80, 100, 120, 140 kVmore » using 400, 255, 180, and 130 mAs, respectively, for the VCT scanner, and 80, 100, 120, and 135 kV using 400, 250, 200, and 150 mAs, respectively, on the Aquilion One. Images were reconstructed at 2.5 mm (VCT) and 0.5 mm (Aquilion One). The VCT images were reconstructed using Advanced Statistical Iterative Reconstruction (ASIR) at 6 different strengths: 0%, 20%, 40%, 60%, 80%, and 100%. Aquilion One images were reconstructed using Adaptive Iterative Dose Reduction (AIDR) at 4 strengths: no AIDR, Weak AIDR, Standard AIDR, and Strong AIDR. Regions of interest (ROIs) were drawn on the images to measure the HU values and standard deviations of the diluted contrast. Second order polynomials were used to fit the HU values as a function of Iodine concentration. Results: For both scanners, there was no significant effect of changing the iterative reconstruction strength. The polynomial fits yielded goodness-of-fit (R2) values averaging 0.997. Conclusion: Changing the strength of the iterative reconstruction has no significant effect on the HU values of Iodinated contrast in a tissue-equivalent phantom. Fit values of HU vs Iodine concentration are useful in quantitative imaging protocols such as the determination of cardiac output from time-density curves in the main pulmonary artery.« less

Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures

NASA Technical Reports Server (NTRS)

Vlahopoulos, Nickolas; Schiller, Noah H.

2011-01-01

The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations. The global system of EFEA equations is solved numerically and the vibration levels within the entire system can be computed. The new EFEA formulation for modeling composite laminate structures is validated through comparison to test data collected from a representative composite aircraft fuselage that is made out of a composite outer shell and composite frames and stiffeners. NASA Langley constructed the composite cylinder and conducted the test measurements utilized in this work.

Determination of natural radionuclides content in some building materials in Nigeria by gamma-ray spectrometry.

PubMed

Ademola, J A

2008-01-01

This paper presents the findings of a study undertaken to determine the natural radioactivity present in some building materials in Nigeria using a gamma-ray spectrometer with a hyper pure germanium detector. A total of 118 samples of commonly used building materials were collected from manufacturers and suppliers of these materials. The mean radioactivity concentrations measured in the different building materials varied from 9.4 to 62.9, 1.3 to 88.4, and 21.5 to 762.4 Bq kg(-1), respectively, for 226Ra, 232Th, and 40K. The average contents of 226Ra, 232Th, and 40K for all the samples were 36.3, 46.5, and 320.9 Bq kg(-1), respectively, lower than the world average for building materials (50, 50, and 500 Bq kg(-1)). The calculated mean radium equivalent activity and external and internal hazard indices for the entire sample were lower than United Nation Scientific Committee on the Effects of Atomic Radiation recommended limits and comparable with results of similar studies undertaken in other countries. The mean annual gonadal equivalent doses of some of the samples were higher than the world average value for soil.

SU-D-BRC-04: Development of Proton Tissue Equivalent Materials for Calibration and Dosimetry Studies

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

Olguin, E; Flampouri, S; Lipnharski, I

Purpose: To develop new proton tissue equivalent materials (PTEM), urethane and fiberglass based, for proton therapy calibration and dosimetry studies. Existing tissue equivalent plastics are applicable only for x-rays because they focus on matching mass attenuation coefficients. This study aims to create new plastics that match mass stopping powers for proton therapy applications instead. Methods: New PTEMs were constructed using urethane and fiberglass resin materials for soft, fat, bone, and lung tissue. The stoichiometric analysis method was first used to determine the elemental composition of each unknown constituent. New initial formulae were then developed for each of the 4 PTEMsmore » using the new elemental compositions and various additives. Samples of each plastic were then created and exposed to a well defined proton beam at the UF Health Proton Therapy Institute (UFHPTI) to validate its mass stopping power. Results: The stoichiometric analysis method revealed the elemental composition of the 3 components used in creating the PTEMs. These urethane and fiberglass based resins were combined with additives such as calcium carbonate, aluminum hydroxide, and phenolic micro spheres to achieve the desired mass stopping powers and densities. Validation at the UFHPTI revealed adjustments had to be made to the formulae, but the plastics eventually had the desired properties after a few iterations. The mass stopping power, density, and Hounsfield Unit of each of the 4 PTEMs were within acceptable tolerances. Conclusion: Four proton tissue equivalent plastics were developed: soft, fat, bone, and lung tissue. These plastics match each of the corresponding tissue’s mass stopping power, density, and Hounsfield Unit, meaning they are truly tissue equivalent for proton therapy applications. They can now be used to calibrate proton therapy treatment planning systems, improve range uncertainties, validate proton therapy Monte Carlo simulations, and assess in-field and out-of-field organ doses.« less

Stabilized pigment and method for producing the same

NASA Technical Reports Server (NTRS)

Morrison, Stanley Roy (Inventor); Freund, Thomas (Inventor)

1976-01-01

A chemical species, present in two oxidation states which differ from one another by one equivalent, is added to pigment materials to serve as a recombination center for alternately capturing electrons and holes produced by the pigment materials when they are subjected to ultraviolet light exposure.

77 FR 2098 - New Postal Product

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-13

... Competitive Products List and Notice of Filing Two Functionally Equivalent Global Plus 1C Contracts Negotiated Service Agreements and Application for Non-Public Treatment of Materials Filed Under Seal, December 30... under seal. Attachment 1 to the Notice is an application for non-public treatment of that material...

Radiation exposure from consumer products and miscellaneous sources

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

Not Available

1977-01-01

This review of the literature indicates that there is a variety of consumer products and miscellaneous sources of radiation that result in exposure to the U.S. population. A summary of the number of people exposed to each such source, an estimate of the resulting dose equivalents to the exposed population, and an estimate of the average annual population dose equivalent are tabulated. A review of the data in this table shows that the total average annual contribution to the whole-body dose equivalent of the U.S. population from consumer products is less than 5 mrem; about 70 percent of this arisesmore » from the presence of naturally-occurring radionuclides in building materials. Some of the consumer product sources contribute exposure mainly to localized tissues or organs. Such localized estimates include: 0.5 to 1 mrem to the average annual population lung dose equivalent (generalized); 2 rem to the average annual population bronchial epithelial dose equivalent (localized); and 10 to 15 rem to the average annual population basal mucosal dose equivalent (basal mucosa of the gum). Based on these estimates, these sources may be grouped or classified as those that involve many people and the dose equivalent is relative large or those that involve many people but the dose equivalent is relatively small, or the dose equivalent is relatively large but the number of people involved is small.« less

Safety and efficacy of overnight orthokeratology in myopic children.

PubMed

Mika, Renée; Morgan, Bruce; Cron, Michael; Lotoczky, Josh; Pole, John

2007-05-01

This prospective case series was conducted to describe the safety and efficacy of orthokeratology with the Emerald Contact Lens for Overnight Orthokeratology (Oprifocon A; Euclid Systems Corporation, Herndon, Virginia) among young myopes. Twenty subjects (ages 10 to 16) were enrolled in the 6-month pilot study. Subjects were fit empirically with overnight orthokeratology lenses and evaluated at 1 day, 1 week, 1 month, 2 months, 3 months, and 6 months. Sixteen subjects completed the study. The mean baseline spherical equivalent refraction (SER) was -2.06 diopters (D) (+/-0.75). The mean SER at 6 months was -0.16 D (+/-0.38). The mean baseline uncorrected acuity was 0.78 (+/-0.28) logarithmic minimum angle of resolution (logMAR) equivalent (20/100 Snellen). The mean logMAR equivalent at 6 months was -0.03 +/- 0.12 (<20/20 Snellen). On average, 40% of eyes showed some type of corneal staining between the 1-week and 6-month visits. No serious adverse events occurred during the study. In contrast to previously published studies that reported maximum results at 2 weeks, subjects reached maximum reduction in myopia at the 1-week visit and, on average, obtained a 92.2% reduction in spherical equivalent refractive error at 6 months. This pilot study lends to a growing body of evidence that short-term correction of mild to moderate myopia with overnight orthokeratology is safe and efficacious in children and adolescents.

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

Dowdy, M.; Burke, A.; Schneider, H.

Fuel economy, exhaust emissions, multifuel capability, advanced materials and cost/manufacturability for both conventional and advanced alternative power systems were assessed. To insure valid comparisons of vehicles with alternative power systems, the concept of an Otto-Engine-Equivalent (OEE) vehicle was utilized. Each engine type was sized to provide equivalent vehicle performance. Sensitivity to different performance criteria was evaluated. Fuel economy projections are made for each engine type considering both the legislated emission standards and possible future emissions requirements.

Equivalent peak resolution: characterization of the extent of separation for two components based on their relative peak overlap.

PubMed

Dvořák, Martin; Svobodová, Jana; Dubský, Pavel; Riesová, Martina; Vigh, Gyula; Gaš, Bohuslav

2015-03-01

Although the classical formula of peak resolution was derived to characterize the extent of separation only for Gaussian peaks of equal areas, it is often used even when the peaks follow non-Gaussian distributions and/or have unequal areas. This practice can result in misleading information about the extent of separation in terms of the severity of peak overlap. We propose here the use of the equivalent peak resolution value, a term based on relative peak overlap, to characterize the extent of separation that had been achieved. The definition of equivalent peak resolution is not constrained either by the form(s) of the concentration distribution function(s) of the peaks (Gaussian or non-Gaussian) or the relative area of the peaks. The equivalent peak resolution value and the classically defined peak resolution value are numerically identical when the separated peaks are Gaussian and have identical areas and SDs. Using our new freeware program, Resolution Analyzer, one can calculate both the classically defined and the equivalent peak resolution values. With the help of this tool, we demonstrate here that the classical peak resolution values mischaracterize the extent of peak overlap even when the peaks are Gaussian but have different areas. We show that under ideal conditions of the separation process, the relative peak overlap value is easily accessible by fitting the overall peak profile as the sum of two Gaussian functions. The applicability of the new approach is demonstrated on real separations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

GEANT4 and PHITS simulations of the shielding of neutrons from the 252Cf source

NASA Astrophysics Data System (ADS)

Shin, Jae Won; Hong, Seung-Woo; Bak, Sang-In; Kim, Do Yoon; Kim, Chong Yeal

2014-09-01

Monte Carlo simulations are performed by using the GEANT4 and the PHITS for studying the neutron-shielding abilities of several materials, such as graphite, iron, polyethylene, NS-4-FR and KRAFTON-HB. As a neutron source, 252Cf is considered. For the Monte Carlo simulations by using the GEANT4, high precision (G4HP) models with the G4NDL 4.2 based on ENDF/B-VII data are used. For the simulations by using the PHITS, the JENDL-4.0 library is used. The neutron-dose-equivalent rates with or without five different shielding materials are estimated and compared with the experimental values. The differences between the shielding abilities calculated by using the GEANT4 with the G4NDL 4.2 and the PHITS with the JENDL-4.0 are found not to be significant for all the cases considered in this work. The neutron-dose-equivalent rates obtained by using the GEANT4 and the PHITS are compared with experimental data and other simulation results. Our neutron-dose-equivalent rates agree well with the experimental dose-equivalent rates, within 20% errors, except for polyethylene. For polyethylene, the discrepancies between our calculations and the experiments are less than 40%, as observed in other simulation results.

EQUIVALENCE BETWEEN SHORT-TIME BIPHASIC AND INCOMPRESSIBLE ELASTIC MATERIAL RESPONSES

PubMed Central

Ateshian, Gerard A.; Ellis, Benjamin J.; Weiss, Jeffrey A.

2009-01-01

Porous-permeable tissues have often been modeled using porous media theories such as the biphasic theory. This study examines the equivalence of the short-time biphasic and incompressible elastic responses for arbitrary deformations and constitutive relations from first principles. This equivalence is illustrated in problems of unconfined compression of a disk, and of articular contact under finite deformation, using two different constitutive relations for the solid matrix of cartilage, one of which accounts for the large disparity observed between the tensile and compressive moduli in this tissue. Demonstrating this equivalence under general conditions provides a rationale for using available finite element codes for incompressible elastic materials as a practical substitute for biphasic analyses, so long as only the short-time biphasic response is sought. In practice, an incompressible elastic analysis is representative of a biphasic analysis over the short-term response δt≪Δ2/‖C4‖||K||, where Δ is a characteristic dimension, C4 is the elasticity tensor and K is the hydraulic permeability tensor of the solid matrix. Certain notes of caution are provided with regard to implementation issues, particularly when finite element formulations of incompressible elasticity employ an uncoupled strain energy function consisting of additive deviatoric and volumetric components. PMID:17536908

Development of a multi-cycle shear-compression testing for the modeling of severe plastic deformation

NASA Astrophysics Data System (ADS)

Pesin, A.; Pustovoytov, D.; Lokotunina, N.

2017-12-01

The mechanism of severe plastic deformation comes from very significant shear strain. Shear-compression testing of materials is complicated by the fact that a state of large equivalent strain with dominant shear strain is not easily achievable. This paper presents the novel technique of laboratory simulation of severe plastic deformation by multi-cycle shear-compression testing at room temperature with equivalent strain e=1…5. The specimen consisted of a parallelepiped having an inclined gauge section created by two diametrically opposed semi-circular slots which were machined at 45°. Height of the specimen was 50 mm, section dimensions were 25×25 mm, gauge thickness was 5.0 mm and gauge width was 6.0 mm. The specimen provided dominant shear strain in an inclined gauge-section. The level of shear strain and equivalent strain was controlled through adjustment of the height reduction of the specimen, load application direction and number of cycles of shear-compression. Aluminium alloy Al-6.2Mg-0.7Mn was used as a material for specimen. FE simulation and analysis of the stress-strain state were performed. The microstructure of the specimen after multi-cycle shear-compression testing with equivalent strain e=1…5 was examined by optical and scanning electron microscope.

Scanning Electron Microscopy (SEM) Procedure for HE Powders on a Zeiss Sigma HD VP SEM

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

Zaka, F.

This method describes the characterization of inert and HE materials by the Zeiss Sigma HD VP field emission Scanning Electron Microscope (SEM). The SEM uses an accelerated electron beam to generate high-magnification images of explosives and other materials. It is fitted with five detectors (SE, Inlens, STEM, VPSE, HDBSD) to enable imaging of the sample via different secondary electron signatures, angles, and energies. In addition to imaging through electron detection, the microscope is also fitted with two Oxford Instrument Energy Dispersive Spectrometer (EDS) 80 mm detectors to generate elemental constituent spectra and two-dimensional maps of the material being scanned.

Dependence of equivalent thermal conductivity coefficients of single-wall carbon nanotubes on their chirality

NASA Astrophysics Data System (ADS)

Zarubin, V. S.; Sergeeva, E. S.

2018-04-01

Composite materials (composites) composed of a matrix and reinforcing components are currently widely used as structural materials for various engineering devices designed to operate under extreme thermal and mechanical loads. By modifying a composite with structure-sensitive inclusions such as single-wall carbon nanotubes, one can significantly improve the thermomechanical properties of the resulting material. The paper presents relationships obtained for the equivalent thermal conductivity coefficients of single-wall carbon nanotubes versus their chirality using a simulation model developed to simulate the heat transfer process through thermal conductivity in a transversely isotropic environment. With these coefficients, one can conventionally substitute a single-wall carbon nanotube with a continuous anisotropic fiber, thus allowing one to estimate the thermal properties of composites reinforced with objects of this sort by using the well-known models developed for fibered composites. The results presented here can be used to estimate the thermal properties of carbon nanotube-reinforced composites.

Experimental Evaluation of Equivalent-Fluid Models for Melamine Foam

NASA Technical Reports Server (NTRS)

Allen, Albert R.; Schiller, Noah H.

2016-01-01

Melamine foam is a soft porous material commonly used in noise control applications. Many models exist to represent porous materials at various levels of fidelity. This work focuses on rigid frame equivalent fluid models, which represent the foam as a fluid with a complex speed of sound and density. There are several empirical models available to determine these frequency dependent parameters based on an estimate of the material flow resistivity. Alternatively, these properties can be experimentally educed using an impedance tube setup. Since vibroacoustic models are generally sensitive to these properties, this paper assesses the accuracy of several empirical models relative to impedance tube measurements collected with melamine foam samples. Diffuse field sound absorption measurements collected using large test articles in a laboratory are also compared with absorption predictions determined using model-based and measured foam properties. Melamine foam slabs of various thicknesses are considered.

Non-detonable and non-explosive explosive simulators

DOEpatents

Simpson, R.L.; Pruneda, C.O.

1997-07-15

A simulator which is chemically equivalent to an explosive, but is not detonable or explodable is disclosed. The simulator is a combination of an explosive material with an inert material, either in a matrix or as a coating, where the explosive has a high surface ratio but small volume ratio. The simulator has particular use in the training of explosives detecting dogs, calibrating analytical instruments which are sensitive to either vapor or elemental composition, or other applications where the hazards associated with explosives is undesirable but where chemical and/or elemental equivalence is required. The explosive simulants may be fabricated by different techniques. A first method involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and a second method involves coating inert substrates with thin layers of explosive. 11 figs.

Finite element simulation and comparison of a shear strain and equivalent strain during ECAP and asymmetric rolling

NASA Astrophysics Data System (ADS)

Pesin, A.; Pustovoytov, D.; Shveyova, T.; Vafin, R.

2017-12-01

The level of a shear strain and equivalent strain plays a key role in terms of the possibility of using the asymmetric rolling process as a method of severe plastic deformation. Strain mode (pure shear or simple shear) can affect very strongly on the equivalent strain and the grain refinement of the material. This paper presents the results of FEM simulations and comparison of the equivalent strain in the aluminium alloy 5083 processed by a single-pass equal channel angular pressing (simple shear), symmetric rolling (pure shear) and asymmetric rolling (simultaneous pure and simple shear). The nonlinear effect of rolls speed ratio on the deformation characteristics during asymmetric rolling was found. Extremely high equivalent strain up to e=4.2 was reached during a single-pass asymmetric rolling. The influence of the shear strain on the level of equivalent strain is discussed. Finite element analysis of the deformation characteristics, presented in this study, can be used for optimization of the asymmetric rolling process as a method of severe plastic deformation.

Optical Analysis of Transparent Polymeric Material Exposed to Simulated Space Environment

NASA Technical Reports Server (NTRS)

Edwards, David L.; Finckenor, Miria M.

1999-01-01

Transparent polymeric materials are being designed and utilized as solar concentrating lenses for spacecraft power and propulsion systems. These polymeric lenses concentrate solar energy onto energy conversion devices such as solar cells and thermal energy systems. The conversion efficiency is directly related to the transmissivity of the polymeric lens. The Environmental Effects Group of the Marshall Space Flight Center's Materials, Processes, and Manufacturing Department exposed a variety of materials to a simulated space environment and evaluated them for an, change in optical transmission. These materials include Lexan(TM), polyethylene terephthalate (PET). several formulations of Tefzel(TM). and Teflon(TM), and silicone DC 93-500. Samples were exposed to a minimum of 1000 Equivalent Sun Hours (ESH) of near-UV radiation (250 - 400 nm wavelength). Data will be presented on materials exposed to charged particle radiation equivalent to a five-year dose in geosynchronous orbit. These exposures were performed in MSFC's Combined Environmental Effects Test Chamber, a unique facility with the capability to expose materials simultaneously or sequentially to protons, low-energy electrons, high-energy electrons, near UV radiation and vacuum UV radiation.Prolonged exposure to the space environment will decrease the polymer film's transmission and thus reduce the conversion efficiency. A method was developed to normalize the transmission loss and thus rank the materials according to their tolerance to space environmental exposure. Spectral results and the material ranking according to transmission loss are presented.

Least Squares Best Fit Method for the Three Parameter Weibull Distribution: Analysis of Tensile and Bend Specimens with Volume or Surface Flaw Failure

NASA Technical Reports Server (NTRS)

Gross, Bernard

1996-01-01

Material characterization parameters obtained from naturally flawed specimens are necessary for reliability evaluation of non-deterministic advanced ceramic structural components. The least squares best fit method is applied to the three parameter uniaxial Weibull model to obtain the material parameters from experimental tests on volume or surface flawed specimens subjected to pure tension, pure bending, four point or three point loading. Several illustrative example problems are provided.

46 CFR 76.25-30 - Piping.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Automatic Sprinkling System, Details § 76.25-30 Piping. (a) All piping, valves, and fittings of ferrous materials shall be... piping, valves, fittings, and sprinkler heads shall be securely supported, and, where necessary...

46 CFR 76.25-30 - Piping.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Automatic Sprinkling System, Details § 76.25-30 Piping. (a) All piping, valves, and fittings of ferrous materials shall be... piping, valves, fittings, and sprinkler heads shall be securely supported, and, where necessary...

46 CFR 76.25-30 - Piping.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Automatic Sprinkling System, Details § 76.25-30 Piping. (a) All piping, valves, and fittings of ferrous materials shall be... piping, valves, fittings, and sprinkler heads shall be securely supported, and, where necessary...

46 CFR 76.25-30 - Piping.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Automatic Sprinkling System, Details § 76.25-30 Piping. (a) All piping, valves, and fittings of ferrous materials shall be... piping, valves, fittings, and sprinkler heads shall be securely supported, and, where necessary...

46 CFR 76.25-30 - Piping.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Automatic Sprinkling System, Details § 76.25-30 Piping. (a) All piping, valves, and fittings of ferrous materials shall be... piping, valves, fittings, and sprinkler heads shall be securely supported, and, where necessary...

77 FR 34457 - Pipeline Safety: Mechanical Fitting Failure Reports

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-11

... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No... notice provides clarification to owners and operators of gas distribution pipeline facilities when... of a gas distribution pipeline facility to file a written report for any mechanical fitting failure...

A decade of Rossi X-ray Timing Explorer Seyfert observations: An RXTE Seyfert spectral database

NASA Astrophysics Data System (ADS)

Mattson, Barbara Jo

2008-10-01

With over forty years of X-ray observations, we should have a grasp on the X- ray nature of active galactic nuclei (AGN). The unification model of Antonucci and Miller (1985) offered a context for understanding observations by defining a "typical" AGN geometry, with observed spectral differences explained by line- of-sight effects. However, the emerging picture is that the central AGN is more complex than unification alone can describe. We explore the unified model with a systematic X-ray spectral study of bright Seyfert galaxies observed by the Rossi X-Ray Timing Explorer (RXTE) over its first 10 years. We develop a spectral-fit database of 821 time-resolved spectra from 39 Seyfert galaxies fitted to a model describing the effects of an X-ray power-law spectrum reprocessed and absorbed by material in the central AGN region. We observe a relationship between radio and X-ray properties for Seyfert 1s, with the spectral parameters differing between radio-loud and radio-quiet Seyfert 1s. We also find a complex relationship between the Fe K equivalent width ( EW ) and the power-law photon index (Gamma) for the Seyfert 1s, with a correlation for the radio-loud sources and an anti-correlation for the radio- quiet sources. These results can be explained if X-rays from the relativistic jet in radio-loud sources contribute significantly to the observed spectrum. We observe scatter in the EW-Gamma relationship for the Seyfert 2s, suggesting complex environments that unification alone cannot explain. We see a strong correlation between Gamma and the reflection fraction ( R ) in the Seyfert 1 and 2 samples, but modeling degeneracies are present, so this relationship cannot be trusted as instructive of the AGN physics. For the Seyfert 1 sample, we find an anticorrelation between EW and the 2 to 10 keV luminosity ( L x ), also known as the X-ray Baldwin effect. This may suggest that higher luminosity sources contain less material or may be due to a time-lag effect. We do not observe the previously reported relationship between Gamma and the ratio of L x to the Eddington luminosity.

Dose measurement in heterogeneous phantoms with an extrapolation chamber

NASA Astrophysics Data System (ADS)

Deblois, Francois

A hybrid phantom-embedded extrapolation chamber (PEEC) made of Solid Water(TM) and bone-equivalent material was used for determining absolute dose in a bone-equivalent phantom irradiated with clinical radiation beams (cobalt-60 gamma rays; 6 and 18 MV x-rays; and 9 and 15 MeV electrons). The dose was determined with the Spencer-Attix cavity theory, using ionization gradient measurements and an indirect determination of the chamber air-mass through measurements of chamber capacitance. The air gaps used were between 2 and 3 mm and the sensitive air volume of the extrapolation chamber was remotely controlled through the motion of the motorized piston with a precision of +/-0.0025 mm. The collected charge was corrected for ionic recombination and diffusion in the chamber air volume following the standard two-voltage technique. Due to the hybrid chamber design, correction factors accounting for scatter deficit and electrode composition were determined and applied in the dose equation to obtain dose data for the equivalent homogeneous bone phantom. Correction factors for graphite electrodes were calculated with Monte Carlo techniques and the calculated results were verified through relative air cavity dose measurements for three different polarizing electrode materials: graphite, steel, and brass in conjunction with a graphite collecting electrode. Scatter deficit, due mainly to loss of lateral scatter in the hybrid chamber, reduces the dose to the air cavity in the hybrid PEEC in comparison with full bone PEEC from 0.7 to ˜2% depending on beam quality and energy. In megavoltage photon and electron beams, graphite electrodes do not affect the dose measurement in the Solid Water(TM) PEEC but decrease the cavity dose by up to 5% in the bone-equivalent PEEC even for very thin graphite electrodes (<0.0025 cm). The collecting electrode material in comparison with the polarizing electrode material has a larger effect on the electrode correction factor; the thickness of thin electrodes, on the other hand, has a negligible effect on dose determination. The uncalibrated hybrid PEEC is an accurate and absolute device for measuring the dose directly in bone material in conjunction with appropriate correction factors determined with Monte Carlo techniques.