maximum spreading diameter: Topics by Science.gov

Sample records for maximum spreading diameter

Droplet impact dynamics for two liquids impinging on anisotropic superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Pearson, John T.; Maynes, Daniel; Webb, Brent W.

2012-09-01

Droplet impingement experiments were performed on grooved hydrophobic surfaces with cavity fractions of 0, 80, and 93 % using droplets of water and a 50 %/50 % water/glycerol mixture. The influence of liquid viscosity, cavity fraction, and spreading direction, relative to the surface grooves, is explored qualitatively and quantitatively. The maximum droplet spread diameter, velocity of the rebounding jet, and the time delay between droplet impact and jet emission were characterized for Weber numbers, We, based on droplet impact speed and diameter, up to 500. The unequal shear stresses and contact angles influence the maximum spread diameters in the two primary spread directions. At We > 100, the ratio of the spread diameter along the direction of the grooves to the spread diameter perpendicular to the grooves increases above unity with increasing We. The maximum droplet spread diameter is compared to recent predictive models, and the data reveal differing behavior for the two fluids considered. The results also reveal the existence of very high relative jet velocities in the range 5 ≤ We ≤ 15 for water droplets, while such jets were not observed for the more viscous mixture. Further, in the range 115 ≤ We ≤ 265, the water/glycerol jet formation dynamics are radically different from the water behavior. Most evident is the existence of two-pronged jets, which arise from the anisotropy of the surface and the unequal shear stresses and contact angles that prevail on the surfaces. It is these influences that give rise to differences in the maximum spread diameters in the two primary spread directions. Similar two-pronged jet emission was observed for water over the very narrow range of We from 91 to 96. The issuing jet velocities were also observed to increase with increasing cavity fraction for both fluids and over the entire range of We explored. Lastly, the elapsed time between droplet impact and jet emission decreased with increasing cavity fraction.
Influence of the impact energy on the pattern of blood drip stains

NASA Astrophysics Data System (ADS)

Smith, F. R.; Nicloux, C.; Brutin, D.

2018-01-01

The maximum spreading diameter of complex fluid droplets has been extensively studied and explained by numerous physical models. This research focuses therefore on a different aspect, the bulging outer rim observed after evaporation on the final dried pattern of blood droplets. A correlation is found between the inner diameter, the maximum outer diameter, and the impact speed. This shows how the drying mechanism of a blood drip stain is influenced by the impact energy, which induces a larger spreading diameter and thus a different redistribution of red blood cells inside the droplet. An empirical relation is established between the final dried pattern of a passive bloodstain and its impact speed, yielding a possible forensic application. Indeed, being able to relate accurately the energy of the drop with its final pattern would give a clue to investigators, as currently no such simple and accurate tool exists.
Wetting and spreading behaviors of impinging microdroplets on textured surfaces

NASA Astrophysics Data System (ADS)

Kwon, Dae Hee; Lee, Sang Joon; CenterBiofluid and Biomimic Reseach Team

2012-11-01

Textured surfaces having an array of microscale pillars have been receiving large attention because of their potential uses for robust superhydrophobic and superoleophobic surfaces. In many practical applications, the textured surfaces usually accompany impinging small-scale droplets. To better understand the impinging phenomena on the textured surfaces, the wetting and spreading behaviors of water microdroplets are investigated experimentally. Microdroplets with diameter less than 50 μm are ejected from a piezoelectric printhead with varying Weber number. The final wetting state of an impinging droplet can be estimated by comparing the wetting pressures of the droplet and the capillary pressure of the textured surface. The wetting behaviors obtained experimentally are well agreed with the estimated results. In addition, the transition from bouncing to non-bouncing behaviors in the partially penetrated wetting state is observed. This transition implies the possibility of withdrawal of the penetrated liquid from the inter-pillar space. The maximum spreading factors (ratio of the maximum spreading diameter to the initial diameter) of the impinging droplets have close correlation with the texture area fraction of the surfaces. This work was supported by Creative Research Initiatives (Diagnosis of Biofluid Flow Phenomena and Biomimic Research) of MEST/KOSEF.
Impinging Water Droplets on Inclined Glass Surfaces

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

Armijo, Kenneth Miguel; Lance, Blake; Ho, Clifford K.

Multiphase computational models and tests of falling water droplets on inclined glass surfaces were developed to investigate the physics of impingement and potential of these droplets to self-clean glass surfaces for photovoltaic modules and heliostats. A multiphase volume-of-fluid model was developed in ANSYS Fluent to simulate the impinging droplets. The simulations considered different droplet sizes (1 mm and 3 mm), tilt angles (0°, 10°, and 45°), droplet velocities (1 m/s and 3 m/s), and wetting characteristics (wetting=47° contact angle and non-wetting = 93° contact angle). Results showed that the spread factor (maximum droplet diameter during impact divided by the initialmore » droplet diameter) decreased with increasing inclination angle due to the reduced normal force on the surface. The hydrophilic surface yielded greater spread factors than the hydrophobic surface in all cases. With regard to impact forces, the greater surface tilt angles yielded lower normal forces, but higher shear forces. Experiments showed that the experimentally observed spread factor (maximum droplet diameter during impact divided by the initial droplet diameter) was significantly larger than the simulated spread factor. Observed spread factors were on the order of 5 - 6 for droplet velocities of ~3 m/s, whereas the simulated spread factors were on the order of 2. Droplets were observed to be mobile following impact only for the cases with 45° tilt angle, which matched the simulations. An interesting phenomenon that was observed was that shortly after being released from the nozzle, the water droplet oscillated (like a trampoline) due to the "snapback" caused by the surface tension of the water droplet being released from the nozzle. This oscillation impacted the velocity immediately after the release. Future work should evaluate the impact of parameters such as tilt angle and surface wettability on the impact of particle/soiling uptake and removal to investigate ways that photovoltaic modules and heliostats can be designed to maximize self-cleaning.« less
Maximum spreading of liquid drop on various substrates with different wettabilities

NASA Astrophysics Data System (ADS)

Choudhury, Raihan; Choi, Junho; Yang, Sangsun; Kim, Yong-Jin; Lee, Donggeun

2017-09-01

This paper describes a novel model developed for a priori prediction of the maximal spread of a liquid drop on a surface. As a first step, a series of experiments were conducted under precise control of the initial drop diameter, its falling height, roughness, and wettability of dry surfaces. The transient liquid spreading was recorded by a high-speed camera to obtain its maximum spreading under various conditions. Eight preexisting models were tested for accurate prediction of the maximum spread; however, most of the model predictions were not satisfactory except one, in comparison with our experimental data. A comparative scaling analysis of the literature models was conducted to elucidate the condition-dependent prediction characteristics of the models. The conditioned bias in the predictions was mainly attributed to the inappropriate formulations of viscous dissipation or interfacial energy of liquid on the surface. Hence, a novel model based on energy balance during liquid impact was developed to overcome the limitations of the previous models. As a result, the present model was quite successful in predicting the liquid spread in all the conditions.
Impact of droplet on superheated surfaces

NASA Astrophysics Data System (ADS)

Lohse, Detlef; Staat, Hendrik J. J.; Tran, Tuan; Prosperetti, Andrea; Sun, Chao

2012-11-01

At impact of a liquid droplet on a smooth surface heated way above the liquid's boiling point, the droplet spreads without any surface contact, floating on its own (Leidenfrost-type) vapor layer, and then bounces back. We show that the dimensionless maximum spreading factor Γ, defined by the ratio of the maximal spreading diameter and the droplet diameter, shows a universal scaling Γ ~ Weγ with the Weber number We - regardless of surface temperature and of liquid properties - which is much steeper than that for the impact on non-heated (hydrophilic or hydrophobic) surfaces, for which γ = 1 / 4 . Based on the idea that the vapor shooting out of the gap between the droplet and the superheated surface drags the liquid outwards, we derive scaling laws for the spreading factor Γ, the vapor layer thickness, and the vapor flow velocity.
Wetting state and maximum spreading factor of microdroplets impacting on superhydrophobic textured surfaces with anisotropic arrays of pillars

NASA Astrophysics Data System (ADS)

Kwon, Dae Hee; Huh, Hyung Kyu; Lee, Sang Joon

2013-07-01

The dynamic behaviors of microdroplets that impact on textured surfaces with various patterns of microscale pillars are experimentally investigated in this study. A piezoelectric inkjet is used to generate the microdroplets that have a diameter of less than 46 μm and a controlled Weber number. The impact and spreading dynamics of an individual droplet are captured by using a high-speed imaging system. The anisotropic and directional wettability and the wetting states on the textured surfaces with anisotropically arranged pillars are revealed for the first time in this study. The impalement transition from the Cassie-Baxter state to the partially impaled state is evaluated by balancing the wetting pressure P wet and the capillary pressure P C even on the anisotropic textured surfaces. The maximum spreading factor is measured and compared with the theoretical prediction to elucidate the wettability of the textured surfaces. For a given Weber number, the maximum spreading factor decreases as the texture area fraction of the textured surface decreases. In addition, the maximum spreading factors along the direction of longer inter-pillar spacing always have smaller values than those along the direction of shorter inter-pillar spacing when a droplet impacts on the anisotropic arrays of pillars.
Impact dynamics of particle-coated droplets

NASA Astrophysics Data System (ADS)

Supakar, T.; Kumar, A.; Marston, J. O.

2017-01-01

We present findings from an experimental study of the impact of liquid marbles onto solid surfaces. Using dual-view high-speed imaging, we reveal details of the impact dynamics previously not reported. During the spreading stage it is observed that particles at the surface flow rapidly to the periphery of the drop, i.e., the lamella. We characterize the spreading with the maximum spread diameter, comparing to impacts of pure liquid droplets. The principal result is a power-law scaling for the normalized maximum spread in terms of the impact Weber number, Dmax/D0˜Weα , with α ≈1 /3 . However, the best description of the spreading is obtained by considering a total energy balance, in a similar fashion to Pasandideh-Fard et al. [Phys. Fluids 8, 650 (1996)], 10.1063/1.868850. By using hydrophilic target surfaces, the marble integrity is lost even for moderate impact speeds as the particles at the surface separate and allow liquid-solid contact to occur. Remarkably, however, we observe no significant difference in the maximum spread between hydrophobic and hydrophilic targets, which is rationalized by the presence of the particles. Finally, for the finest particles used, we observe the formation of nonspherical arrested shapes after retraction and rebound from hydrophobic surfaces, which is quantified by a circularity measurement of the side profiles.
Predictive Model of Supercooled Water Droplet Pinning/Repulsion Impacting a Superhydrophobic Surface: The Role of the Gas-Liquid Interface Temperature.

PubMed

Mohammadi, Morteza; Tembely, Moussa; Dolatabadi, Ali

2017-02-28

Dynamical analysis of an impacting liquid drop on superhydrophobic surfaces is mostly carried out by evaluating the droplet contact time and maximum spreading diameter. In this study, we present a general transient model of the droplet spreading diameter developed from the previously defined mass-spring model for bouncing drops. The effect of viscosity was also considered in the model by definition of a dash-pot term extracted from experiments on various viscous liquid droplets on a superhydrophobic surface. Furthermore, the resultant shear force of the stagnation air flow was also considered with the help of the classical Homann flow approach. It was clearly shown that the proposed model predicts the maximum spreading diameter and droplet contact time very well. On the other hand, where stagnation air flow is present in contradiction to the theoretical model, the droplet contact time was reduced as a function of both droplet Weber numbers and incoming air velocities. Indeed, the reduction in the droplet contact time (e.g., 35% at a droplet Weber number of up to 140) was justified by the presence of a formed thin air layer underneath the impacting drop on the superhydrophobic surface (i.e., full slip condition). Finally, the droplet wetting model was also further developed to account for low temperature through the incorporation of classical nucleation theory. Homogeneous ice nucleation was integrated into the model through the concept of the reduction of the supercooled water drop surface tension as a function of the gas-liquid interface temperature, which was directly correlated with the Nusselt number of incoming air flow. It was shown that the experimental results was qualitatively predicted by the proposed model under all supercooling conditions (i.e., from -10 to -30 °C).
Optimization of post-column reactor radius in capillary high performance liquid chromatography Effect of chromatographic column diameter and particle diameter

PubMed Central

Xu, Hongjuan; Weber, Stephen G.

2006-01-01

A post-column reactor consisting of a simple open tube (Capillary Taylor Reactor) affects the performance of a capillary LC in two ways: stealing pressure from the column and adding band spreading. The former is a problem for very small radius reactors, while the latter shows itself for large reactor diameters. We derived an equation that defines the observed number of theoretical plates (Nobs) taking into account the two effects stated above. Making some assumptions and asserting certain conditions led to a final equation with a limited number of variables, namely chromatographic column radius, reactor radius and chromatographic particle diameter. The assumptions and conditions are that the van Deemter equation applies, the mass transfer limitation is for intraparticle diffusion in spherical particles, the velocity is at the optimum, the analyte’s retention factor, k′, is zero, the post-column reactor is only long enough to allow complete mixing of reagents and analytes and the maximum operating pressure of the pumping system is used. Optimal ranges of the reactor radius (ar) are obtained by comparing the number of observed theoretical plates (and theoretical plates per time) with and without a reactor. Results show that the acceptable reactor radii depend on column diameter, particle diameter, and maximum available pressure. Optimal ranges of ar become narrower as column diameter increases, particle diameter decreases or the maximum pressure is decreased. When the available pressure is 4000 psi, a Capillary Taylor Reactor with 12 μm radius is suitable for all columns smaller than 150 μm (radius) packed with 2–5 μm particles. For 1 μm packing particles, only columns smaller than 42.5 μm (radius) can be used and the reactor radius needs to be 5 μm. PMID:16494886
High power thyristors with 5 kV blocking voltage. Volume 1: Development of high-voltage-thyristors (4.5 kV) with good dynamic properties

NASA Technical Reports Server (NTRS)

Lock, K.; Patalong, H.; Platzoeder, K.

1979-01-01

Using neutron irradiated silicon with considerably lower spread in resistivity as compared to conventionally doped silicon it was possible to produce power thyristors with breakdown voltages between 3.5 kV and 5.5 kV. The thyristor pellets have a diameter of 50 mm. Maximum average on-state currents of 600 to 800 A can be reached with these elements. The dynamic properties of the thryistors could be improved to allow standard applications up to maximum repetitive voltages of 4.5 kV.
Numerical study of liquid film rupture after droplet spreading on a superhydrophilic surface

NASA Astrophysics Data System (ADS)

Guo, Yisen; Lian, Yongsheng

2017-11-01

When a droplet impacts onto a solid surface, different outcomes can be observed, such as rebound, spreading and splashing. We present numerical simulation results on liquid film rupture after spreading of a droplet impact on a smooth superhydrophilic surface. The Navier-Stokes equations are solved using the variable density pressure projection method and the moment-of-fluid method is used to track the droplet interface. A superhydrophilic or superwetting surface has strong affinity to liquid and we assume the contact angle between solid and liquid is almost zero degree. The droplet spreading and film rupture process occurs in two stages: the droplet first spreads onto the surface and flattens into a thin film as it reaches the maximum diameter, then the film rim becomes unstable and the film rupture initiates from the rim toward the center gradually until the entire film breaks up into secondary droplets. The duration of the film rupture stage is much shorter than the spreading stage. The simulation result is compared with experiment and good agreement is achieved. We investigate the film thickness evolution during spreading and the effect of surface wettability on film rupture.
Droplet impact on regular micro-grooved surfaces

NASA Astrophysics Data System (ADS)

Hu, Hai-Bao; Huang, Su-He; Chen, Li-Bin

2013-08-01

We have investigated experimentally the process of a droplet impact on a regular micro-grooved surface. The target surfaces are patterned such that micro-scale spokes radiate from the center, concentric circles, and parallel lines on the polishing copper plate, using Quasi-LIGA molding technology. The dynamic behavior of water droplets impacting on these structured surfaces is examined using a high-speed camera, including the drop impact processes, the maximum spreading diameters, and the lengths and numbers of fingers at different values of Weber number. Experimental results validate that the spreading processes are arrested on all target surfaces at low velocity. Also, the experimental results at higher impact velocity demonstrate that the spreading process is conducted on the surface parallel to the micro-grooves, but is arrested in the direction perpendicular to the micro-grooves. Besides, the lengths of fingers increase observably, even when they are ejected out as tiny droplets along the groove direction, at the same time the drop recoil velocity is reduced by micro-grooves which are parallel to the spreading direction, but not by micro-grooves which are vertical to the spreading direction.
Narrow Energy Spread Protons and Ions from High-Intensity, High-Contrast Laser Solid Target Interactions

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

Dollar, Franklin; Matsuoka, Takeshi; McGuffey, Christopher

2010-11-04

Recent simulations show that an idealized, high intensity, short pulse laser can generate quasi-monoenergetic proton beams with energies over 100 MeV in an interaction with a thin film. However, most short pulse laser facilities with sufficient intensity have difficulty controlling the nanosecond and picosecond contrast necessary to realize such a regime. Experiments were performed to investigate proton and ion acceleration from a high contrast, short pulse laser by employing dual plasma mirrors along with a deformable mirror at the HERCULES laser facility at the Center for Ultrafast Optical Sciences, University of Michigan. Plasma mirrors were characterized, allowing a 50% throughputmore » with an intensity contrast increase of 105. The focal spot quality was also exceptional, showing a 1.1 micron full width at half maximum (FWHM) focal diameter. Experiments were done using temporally cleaned 30 TW, 32 fs pulses to achieve an intensity of up to 10{sup 21} Wcm{sup -2} on Si{sub 3}N{sub 4} and Mylar targets with thicknesses ranging 50 nm to 13 microns. Proton beams with energy spreads below 2 MeV were observed from all thicknesses, peaking with energies up to 10.3 MeV and an energy spread of 0.8 MeV. Similar narrow energy spreads were observed for oxygen, nitrogen, and carbon at the silicon nitride thickness of 50 nm with energies up to 24 MeV with an energy spread of 3 MeV, whereas the energy spread is greatly increased at a larger thickness. Maximum energies were confirmed with CR39 track detectors, while a Thomson ion spectrometer was used to gauge the monoenergetic nature of the beam.« less
Quantification of pulmonary vessel diameter in low-dose CT images

NASA Astrophysics Data System (ADS)

Rudyanto, Rina D.; Ortiz de Solórzano, Carlos; Muñoz-Barrutia, Arrate

2015-03-01

Accurate quantification of vessel diameter in low-dose Computer Tomography (CT) images is important to study pulmonary diseases, in particular for the diagnosis of vascular diseases and the characterization of morphological vascular remodeling in Chronic Obstructive Pulmonary Disease (COPD). In this study, we objectively compare several vessel diameter estimation methods using a physical phantom. Five solid tubes of differing diameters (from 0.898 to 3.980 mm) were embedded in foam, simulating vessels in the lungs. To measure the diameters, we first extracted the vessels using either of two approaches: vessel enhancement using multi-scale Hessian matrix computation, or explicitly segmenting them using intensity threshold. We implemented six methods to quantify the diameter: three estimating diameter as a function of scale used to calculate the Hessian matrix; two calculating equivalent diameter from the crosssection area obtained by thresholding the intensity and vesselness response, respectively; and finally, estimating the diameter of the object using the Full Width Half Maximum (FWHM). We find that the accuracy of frequently used methods estimating vessel diameter from the multi-scale vesselness filter depends on the range and the number of scales used. Moreover, these methods still yield a significant error margin on the challenging estimation of the smallest diameter (on the order or below the size of the CT point spread function). Obviously, the performance of the thresholding-based methods depends on the value of the threshold. Finally, we observe that a simple adaptive thresholding approach can achieve a robust and accurate estimation of the smallest vessels diameter.
Effects of Evaporation/Condensation on Spreading and Contact Angle of a Volatile Liquid Drop

NASA Technical Reports Server (NTRS)

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

2000-01-01

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

NASA Astrophysics Data System (ADS)

Kuz’min, A. A.; Kulagin, O. V.; Rodchenkov, V. I.

2018-04-01

Compression of pulsed Nd : glass laser radiation under stimulated Brillouin scattering (SBS) in perfluorooctane is investigated. Compression of 16-ns pulses at a beam diameter of 30 mm is implemented. The maximum compression coefficient is 28 in the optimal range of laser pulse energies from 2 to 4 J. The Stokes pulse power exceeds that of the initial laser pulse by a factor of about 11.5. The Stokes pulse jitter (fluctuations of the Stokes pulse exit time from the compressor) is studied. The rms spread of these fluctuations is found to be 0.85 ns.
Three-dimensional workstation is useful for measuring the correct size of abdominal aortic aneurysm diameters.

PubMed

Ihara, Tsutomu; Komori, Kimihiro; Yamamoto, Kiyohito; Kobayashi, Masayoshi; Banno, Hiroshi; Kodama, Akio

2013-02-01

Abdominal aortic aneurysm diameter is usually measured by the maximum minor-axis diameter on axial computed tomography (CT). However, this "traditional" diameter may underestimate the real size, as the aorta is not always straight and the aneurysm shape is sometimes in the form of an ellipse along the cross section. Therefore, we measured maximum major-axis diameters using a three-dimensional (3D) workstation and compared them with the traditional maximum minor-axis diameters measured using thin-slice axial CT. CT data of 141 AAA patients (with fusiform aneurysms) were stored in a 3D workstation. These thin-slice CT images were reviewed on the 3D workstation to obtain curved multiplanar reconstruction images (CPR images). Using the CPR images, we measured the maximum major-axis and minor-axis diameters on CPR and the angle of the aneurysms to the body axis. The mean traditional maximum minor-axis diameter was 51.2 ± 8.2 mm, whereas the mean maximum major-axis diameter on CPR was 54.7 ± 10.1 mm. Sixty eight patients had a mean aneurysm size of <50 mm when measured by the traditional minor-axis diameter. Among these patients, five (7.4%) had a major-axis diameter >55 mm on CPR. The measurement of the traditional maximum minor-axis diameter of aneurysms is useful in the case of most patients. However, the traditional maximum minor-axis diameter may underestimate the real aneurysmal diameter, particularly in patients with an ellipse-shaped aneurysm. The maximum major-axis diameter as measured using CPR images is effective for representing the real aneurysmal size. Copyright © 2013 Elsevier Inc. All rights reserved.
Influence of solidification on the impact of supercooled water drops onto cold surfaces

NASA Astrophysics Data System (ADS)

Li, Hai; Roisman, Ilia V.; Tropea, Cameron

2015-06-01

This study presents an experimental investigation of the impact of a supercooled drop onto hydrophilic and superhydrophobic substrates. The aim is to better understand the process of airframe icing caused by supercooled large droplets, which has been recently identified as a severe hazard in aviation. The Weber number and Reynolds number of the impinging drop ranged from 200 to 300 and from 2600 to 5800, respectively. Drop impact, spreading, and rebound were observed using a high-speed video system. The maximum spreading diameter of an impacting drop on hydrophilic surfaces was measured. The temperature effect on this parameter was only minor for a wide range of the drop and substrate temperatures. However, ice/water mixtures emerged when both the drop and substrate temperatures were below 0 °C. Similarly, drop rebound on superhydrophobic substrates was significantly hindered by solidification when supercooled drop impacted onto substrates below the freezing point. The minimum receding diameter and the speed of ice accretion on the substrate were measured for various wall temperatures. Both parameters increased almost linearly with decreasing wall temperature, but eventually leveled off beyond a certain substrate temperature. The rate of ice formation on the substrate was significantly higher than the growth rate of free ice dendrites, implying that multiple nucleation sites were present.
Passive bloodstains: from an impact energy to a final dried pattern

NASA Astrophysics Data System (ADS)

Smith, Fiona; Brutin, David

2016-11-01

Tracking down the origin of a blood droplet present on a crime scene has become of major importance in bloodstain pattern analysis. Passive bloodstains are not yet well understood. Accordingly the purpose of this research is to provide new tools to forensic investigators in the analysis of bloodstains arising from blood droplets dripping naturally. The study aims to understand the link between the final dried pattern of a passive bloodstain and its impact energy. Currently no such tool exists, and no correlation has yet been proven. This research was therefore focusing on a new parameter, the thicker outer rim observed on the dried final pattern. To do so, we created several passive bloodstains with different impact energies. A correlation was highlighted between the inner diameter, the maximum spreading diameter, the initial diameter of a blood droplet and its impact energy. This correlation shows how the drying mechanism of a blood droplet is influenced by its impact energy as it alters the red blood cells dispersion inside the droplet. The biological deposit and the final dried pattern are subsequently modified. ANR funded project: D-Blood Project.

Elliptical spreading characteristics of a liquid metal droplet impact on a glass surface under a horizontal magnetic field

NASA Astrophysics Data System (ADS)

Yang, Juan-Cheng; Qi, Tian-Yu; Han, Tian-Yang; Zhang, Jie; Ni, Ming-Jiu

2018-01-01

The spreading characteristics of a liquid GaInSn alloy droplet on a glass surface with the action of a horizontal magnetic field have been experimentally investigated in the present paper. With changing the impact velocity from 0.1 m/s to 1.2 m/s and increasing the magnetic field from 0 T to 1.6 T, we focus on studying the influence of the horizontal magnetic field on the spreading characteristics of a liquid metal droplet using the shadow-graph method. The elliptical spreading pattern of a liquid metal droplet induced by the horizontal magnetic field was discovered by experiments. By introducing a numerical method in getting the distribution of current lines and the Lorentz force inside the droplet, we give a detailed explanation on the mechanism of elliptical spreading. Furthermore, some quantitative results on a maximum spreading factor and time at moment of maximum spreading varied with the Hartmann number and Weber number are shown to give us a comprehensive understanding of the elliptical spreading. With the increasing of the magnetic field, the maximum spreading factor in the front view is reduced while that in the side view is increased, which reveals a larger deformation happened during the spreading process. While with the increasing of impact velocity, the spreading factor increased. Finally, we present a non-dimensional parameter to get scaling laws for the averaged maximum spreading factor and the aspect ratio of the maximum spreading factor; results show that the predict data can agree with experimental data in a certain degree.
Fast-response variable focusing micromirror array lens

NASA Astrophysics Data System (ADS)

Boyd, James G., IV; Cho, Gyoungil

2003-07-01

A reflective type Fresnel lens using an array of micromirrors is designed and fabricated using the MUMPs® surface micromachining process. The focal length of the lens can be rapidly changed by controlling both the rotation and translation of electrostatically actuated micromirrors. The rotation converges rays and the translation adjusts the optical path length difference of the rays to be integer multiples of the wavelength. The suspension spring, pedestal and electrodes are located under the mirror to maximize the optical efficiency. Relations are provided for the fill-factor and the numerical aperture as functions of the lens diameter, the mirror size, and the tolerances specified by the MUMPs® design rules. The fabricated lens is 1.8mm in diameter, and each micromirror is approximately 100mm x 100mm. The lens fill-factor is 83.7%, the numerical aperture is 0.018 for a wavelength of 632.8nm, and the resolution is approximately 22mm, whereas the resolution of a perfect aberration-free lens is 21.4μm for a NA of 0.018. The focal length ranges from 11.3mm to infinity. The simulated Strehl ratio, which is the ratio of the point spread function maximum intensity to the theoretical diffraction-limited PSF maximum intensity, is 31.2%. A mechanical analysis was performed using the finite element code IDEAS. The combined maximum rotation and translation produces a maximum stress of 301MPa, below the yield strength of polysilicon, 1.21 to 1.65GPa. Potential applications include adaptive microscope lenses for scanning particle imaging velocimetry and a visually aided micro-assembly.
Modelling the minislump spread of superplasticized PPC paste using RLS with the application of Random Kitchen sink

NASA Astrophysics Data System (ADS)

Sathyan, Dhanya; Anand, K. B.; Jose, Chinnu; Aravind, N. R.

2018-02-01

Super plasticizers(SPs) are added to the concrete to improve its workability with out changing the water cement ratio. Property of fresh concrete is mainly governed by the cement paste which depends on the dispersion of cement particle. Cement dispersive properties of the SP depends up on its dosage and the family. Mini slump spread diameter with different dosages and families of SP is taken as the measure of workability characteristic of cement paste chosen for measuring the rheological properties of cement paste. The main purpose of this study includes measure the dispersive ability of different families of SP by conducting minislump test and model the minislump spread diameter of the super plasticized Portland Pozzolona Cement (PPC)paste using regularized least square (RLS) approach along with the application of Random kitchen sink (RKS) algorithm. For preparing test and training data for the model 287 different mixes were prepared in the laboratory at a water cement ratio of 0.37 using four locally available brand of Portland Pozzolona cement (PPC) and SP belonging to four different families. Water content, cement weight and amount of SP (by considering it as seven separate input based on their family and brand) were the input parameters and mini slump spread diameter was the output parameter for the model. The variation of predicted and measured values of spread diameters were compared and validated. From this study it was observed that, the model could effectively predict the minislump spread of cement paste
Maximum Diameter Measurements of Aortic Aneurysms on Axial CT Images After Endovascular Aneurysm Repair: Sufficient for Follow-up?

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

Baumueller, Stephan, E-mail: Stephan.Baumueller@usz.ch; Nguyen, Thi Dan Linh, E-mail: ThiDanLinh.Nguyen@usz.ch; Goetti, Robert Paul, E-mail: RobertPaul.Goetti@usz.ch

2011-12-15

Purpose: To assess the accuracy of maximum diameter measurements of aortic aneurysms after endovascular aneurysm repair (EVAR) on axial computed tomographic (CT) images in comparison to maximum diameter measurements perpendicular to the intravascular centerline for follow-up by using three-dimensional (3D) volume measurements as the reference standard. Materials and Methods: Forty-nine consecutive patients (73 {+-} 7.5 years, range 51-88 years), who underwent EVAR of an infrarenal aortic aneurysm were retrospectively included. Two blinded readers twice independently measured the maximum aneurysm diameter on axial CT images performed at discharge, and at 1 and 2 years after intervention. The maximum diameter perpendicular tomore » the centerline was automatically measured. Volumes of the aortic aneurysms were calculated by dedicated semiautomated 3D segmentation software (3surgery, 3mensio, the Netherlands). Changes in diameter of 0.5 cm and in volume of 10% were considered clinically significant. Intra- and interobserver agreements were calculated by intraclass correlations (ICC) in a random effects analysis of variance. The two unidimensional measurement methods were correlated to the reference standard. Results: Intra- and interobserver agreements for maximum aneurysm diameter measurements were excellent (ICC = 0.98 and ICC = 0.96, respectively). There was an excellent correlation between maximum aneurysm diameters measured on axial CT images and 3D volume measurements (r = 0.93, P < 0.001) as well as between maximum diameter measurements perpendicular to the centerline and 3D volume measurements (r = 0.93, P < 0.001). Conclusion: Measurements of maximum aneurysm diameters on axial CT images are an accurate, reliable, and robust method for follow-up after EVAR and can be used in daily routine.« less
Chlorhexidine droplet splash from a skin preparation gallipot: effect of height of pouring.

PubMed

Evans, L; Cunningham, M; Tilakaratna, P

2013-12-01

Chlorhexidine contamination of equipment used in central neuraxial anaesthesia has been implicated in causing adhesive arachnoiditis. We measured the extent of chlorhexidine splash during pouring into a gallipot (antiseptic skin preparation container) from heights of 5 cm, 10 cm, 15 cm and 20 cm. Twenty experiments were performed at each height. Measurements made up to a horizontal distance of 40 cm radius from the gallipot showed a median (IQR [range]) maximum spread of splash droplets ≥ 2 mm diameter of 26.2 (10.2-36.4 [0-40]) cm. The 40-cm radius measurement area was divided into 5-cm-wide zones to assess spread. At pouring heights of 15 cm and 20 cm, all zones were contaminated. These results demonstrate that pouring chlorhexidine into a gallipot generates significant splash, and we recommend that this should be avoided near equipment used for neuraxial anaesthesia. © 2013 The Association of Anaesthetists of Great Britain and Ireland.
Efficiency and Safety: The Best Time to Valve a Plaster Cast.

PubMed

Steiner, Samuel R H; Gendi, Kirollos; Halanski, Matthew A; Noonan, Kenneth J

2018-04-18

The act of applying, univalving, and spreading a plaster cast to accommodate swelling is commonly performed; however, cast saws can cause thermal and/or abrasive injury to the patient. This study aims to identify the optimal time to valve a plaster cast so as to reduce the risk of cast-saw injury and increase spreading efficiency. Plaster casts were applied to life-sized pediatric models and were univalved at set-times of 5, 8, 12, or 25 minutes. Outcome measures included average and maximum force applied during univalving, blade-to-skin touches, cut time, force needed to spread, number of spread attempts, spread completeness, spread distance, saw blade temperature, and skin surface temperature. Casts allowed to set for ≥12 minutes had significantly fewer blade-to-skin touches compared with casts that set for <12 minutes (p < 0.001). For average and maximum saw blade force, no significant difference was observed between individual set-times. However, in a comparison of the shorter group (<12 minutes) and the longer group (≥12 minutes), the longer group had a higher average force (p = 0.009) but a lower maximum force (p = 0.036). The average temperature of the saw blade did not vary between groups. The maximum force needed to "pop," or spread, the cast was greater for the 5-minute and 8-minute set-times. Despite requiring more force to spread the cast, 0% of attempts at 5 minutes and 54% of attempts at 8 minutes were successful in completely spreading the cast, whereas 100% of attempts at 12 and 25 minutes were successful. The spread distance was greatest for the 12-minute set-time at 5.7 mm. Allowing casts to set for 12 minutes is associated with decreased blade-to-skin contact, less maximum force used with the saw blade, and a more effective spread. Adherence to the 12-minute interval could allow for fewer cast-saw injuries and more effective spreading.
Influence of bronchial diameter change on the airflow dynamics based on a pressure-controlled ventilation system.

PubMed

Ren, Shuai; Cai, Maolin; Shi, Yan; Xu, Weiqing; Zhang, Xiaohua Douglas

2018-03-01

Bronchial diameter is a key parameter that affects the respiratory treatment of mechanically ventilated patients. In this paper, to reveal the influence of bronchial diameter on the airflow dynamics of pressure-controlled mechanically ventilated patients, a new respiratory system model is presented that combines multigeneration airways with lungs. Furthermore, experiments and simulation studies to verify the model are performed. Finally, through the simulation study, it can be determined that in airway generations 2 to 7, when the diameter is reduced to half of the original value, the maximum air pressure (maximum air pressure in lungs) decreases by nearly 16%, the maximum flow decreases by nearly 30%, and the total airway pressure loss (sum of each generation pressure drop) is more than 5 times the original value. Moreover, in airway generations 8 to 16, with increasing diameter, the maximum air pressure, maximum flow, and total airway pressure loss remain almost constant. When the diameter is reduced to half of the original value, the maximum air pressure decreases by 3%, the maximum flow decreases by nearly 5%, and the total airway pressure loss increases by 200%. The study creates a foundation for improvement in respiratory disease diagnosis and treatment. Copyright © 2017 John Wiley & Sons, Ltd.
Impact dynamics of liquid marbles

NASA Astrophysics Data System (ADS)

Marston, Jeremy; Supakar, Tinku

2016-11-01

The impact of particle coated droplets (a.k.a. liquid marbles or armored droplets) onto solid substrates is assessed experimentally with high-speed video. The impact is characterized by the maximum spread diameter, which conforms to scaling laws in terms of the impact Weber number, meaning that the marbles behave similar to water droplets during this stage. However, the motion of the particles across the surface allows us to observe both clustering and divergence of the particle shell and, in particular, we observe the formation of arrested shapes (i.e. jammed interfaces) after impact onto hydrophobic surfaces, from an initially spherical shape. In this case, we postulate that the speed of retraction and rate of change of surface coverage is a key ingredient leading to arrested shapes.
Drop impact on spherical soft surfaces

NASA Astrophysics Data System (ADS)

Chen, Simeng; Bertola, Volfango

2017-08-01

The impact of water drops on spherical soft surfaces is investigated experimentally through high-speed imaging. The effect of a convex compliant surface on the dynamics of impacting drops is relevant to various applications, such as 3D ink-jet printing, where drops of fresh material impact on partially cured soft substrates with arbitrary shape. Several quantities which characterize the morphology of impacting drops are measured through image-processing, including the maximum and minimum spreading angles, length of the wetted curve, and dynamic contact angle. In particular, the dynamic contact angle is measured using a novel digital image-processing scheme based on a goniometric mask, which does not require edge fitting. It is shown that the surface with a higher curvature enhances the retraction of the spreading drop; this effect may be due to the difference of energy dissipation induced by the curvature of the surface. In addition, the impact parameters (elastic modulus, diameter ratio, and Weber number) are observed to significantly affect the dynamic contact angle during impact. A quantitative estimation of the deformation energy shows that it is significantly smaller than viscous dissipation.
Design of Tools for Press-countersinking or Dimpling 0.040-inch-thick-24S-T Sheet

NASA Technical Reports Server (NTRS)

Templin, R L; Fogwell, J W

1942-01-01

A set of dimpling tools was designed for 0.040-inch 24S-T sheet and flush-type rivets 1/8 inch in diameter with 100 degree countersunk heads. The dimples produced under different conditions of pressure, sheet thickness, and drill diameter are presented as cross-sectional photographs magnified 20 times. The most satisfactory values for the dimpling tools were found to be: maximum punch diameter, 0.231 inch; maximum die diameter, 0.223 inch; maximum mandrel diameter, 0.128 inch; dimple angle, 100 degree; punch springback angle, 1 1/2 degree; and die springback angle, 2 degree.
Synthesis of Au microwires by selective oxidation of Au–W thin-film composition spreads

PubMed Central

Hamann, Sven; Brunken, Hayo; Salomon, Steffen; Meyer, Robert; Savan, Alan; Ludwig, Alfred

2013-01-01

We report on the stress-induced growth of Au microwires out of a surrounding Au–W matrix by selective oxidation, in view of a possible application as ‘micro-Velcro’. The Au wires are extruded due to the high compressive stress in the tungsten oxide formed by oxidation of elemental W. The samples were fabricated as a thin-film materials library using combinatorial sputter deposition followed by thermal oxidation. Sizes and shapes of the Au microwires were investigated as a function of the W to Au ratio. The coherence length and stress state of the Au microwires were related to their shape and plastic deformation. Depending on the composition of the Au–W precursor, the oxidized samples showed regions with differently shaped Au microwires. The Au48W52 composition yielded wires with the maximum length to diameter ratio due to the high compressive stress in the tungsten oxide matrix. The values of wire length (35 μm) and diameter (2 μm) achieved at the Au48W52 composition are suitable for micro-Velcro applications. PMID:27877561
Clinical evaluation of whole-body oncologic PET with time-of-flight and point-spread function for the hybrid PET/MR system.

PubMed

Shang, Kun; Cui, Bixiao; Ma, Jie; Shuai, Dongmei; Liang, Zhigang; Jansen, Floris; Zhou, Yun; Lu, Jie; Zhao, Guoguang

2017-08-01

Hybrid positron emission tomography/magnetic resonance (PET/MR) imaging is a new multimodality imaging technology that can provide structural and functional information simultaneously. The aim of this study was to investigate the effects of the time-of-flight (TOF) and point-spread function (PSF) on small lesions observed in PET/MR images from clinical patient image sets. This study evaluated 54 small lesions in 14 patients who had undergone 18 F-fluorodeoxyglucose (FDG) PET/MR. Lesions up to 30mm in diameter were included. The PET data were reconstructed with a baseline ordered-subsets expectation-maximization (OSEM) algorithm, OSEM+PSF, OSEM+TOF and OSEM+TOF+PSF. PET image quality and small lesions were visually evaluated and scored by a 3-point scale. A quantitative analysis was then performed using the mean and maximum standardized uptake value (SUV) of the small lesions (SUV mean and SUV max ). The lesions were divided into two groups according to the long-axis diameter and the location respectively and evaluated with each reconstruction algorithm. We also evaluated the background signal by analyzing the SUV liver . OSEM+TOF+PSF provided the highest value and OSEM+TOF or PSF showed a higher value than OSEM for the visual assessment and quantitative analysis. The combination of TOF and PSF increased the SUV mean by 26.6% and the SUV max by 30.0%. The SUV liver was not influenced by PSF or TOF. For the OSEM+TOF+PSF model, the change in SUV mean and SUV max for lesions <10mm in diameter was 31.9% and 35.8%, and 24.5% and 27.6% for lesions 10-30mm in diameter, respectively. The abdominal lesions obtained the higher SUV than those of chest on the images with TOF and/or PSF. Application of TOF and PSF significantly increased the SUV of small lesions in hybrid PET/MR images, potentially improving small lesion detectability. Copyright © 2017 Elsevier B.V. All rights reserved.
The edge artifact in the point-spread function-based PET reconstruction at different sphere-to-background ratios of radioactivity.

PubMed

Kidera, Daisuke; Kihara, Ken; Akamatsu, Go; Mikasa, Shohei; Taniguchi, Takafumi; Tsutsui, Yuji; Takeshita, Toshiki; Maebatake, Akira; Miwa, Kenta; Sasaki, Masayuki

2016-02-01

The aim of this study was to quantitatively evaluate the edge artifacts in PET images reconstructed using the point-spread function (PSF) algorithm at different sphere-to-background ratios of radioactivity (SBRs). We used a NEMA IEC body phantom consisting of six spheres with 37, 28, 22, 17, 13 and 10 mm in inner diameter. The background was filled with (18)F solution with a radioactivity concentration of 2.65 kBq/mL. We prepared three sets of phantoms with SBRs of 16, 8, 4 and 2. The PET data were acquired for 20 min using a Biograph mCT scanner. The images were reconstructed with the baseline ordered subsets expectation maximization (OSEM) algorithm, and with the OSEM + PSF correction model (PSF). For the image reconstruction, the number of iterations ranged from one to 10. The phantom PET image analyses were performed by a visual assessment of the PET images and profiles, a contrast recovery coefficient (CRC), which is the ratio of SBR in the images to the true SBR, and the percent change in the maximum count between the OSEM and PSF images (Δ % counts). In the PSF images, the spheres with a diameter of 17 mm or larger were surrounded by a dense edge in comparison with the OSEM images. In the spheres with a diameter of 22 mm or smaller, an overshoot appeared in the center of the spheres as a sharp peak in the PSF images in low SBR. These edge artifacts were clearly observed in relation to the increase of the SBR. The overestimation of the CRC was observed in 13 mm spheres in the PSF images. In the spheres with a diameter of 17 mm or smaller, the Δ % counts increased with an increasing SBR. The Δ % counts increased to 91 % in the 10-mm sphere at the SBR of 16. The edge artifacts in the PET images reconstructed using the PSF algorithm increased with an increasing SBR. In the small spheres, the edge artifact was observed as a sharp peak at the center of spheres and could result in overestimation.
Thermal resistance of etched-pillar vertical-cavity surface-emitting laser diodes

NASA Astrophysics Data System (ADS)

Wipiejewski, Torsten; Peters, Matthew G.; Young, D. Bruce; Thibeault, Brian; Fish, Gregory A.; Coldren, Larry A.

1996-03-01

We discuss our measurements on thermal impedance and thermal crosstalk of etched-pillar vertical-cavity lasers and laser arrays. The average thermal conductivity of AlAs-GaAs Bragg reflectors is estimated to be 0.28 W/(cmK) and 0.35W/(cmK) for the transverse and lateral direction, respectively. Lasers with a Au-plated heat spreading layer exhibit a 50% lower thermal impedance compared to standard etched-pillar devices resulting in a significant increase of maximum output power. For an unmounted laser of 64 micrometer diameter we obtain an improvement in output power from 20 mW to 42 mW. The experimental results are compared with a simple analytical model showing the importance of heat sinking for maximizing the output power of vertical-cavity lasers.
Validating automated kidney stone volumetry in computed tomography and mathematical correlation with estimated stone volume based on diameter.

PubMed

Wilhelm, Konrad; Miernik, Arkadiusz; Hein, Simon; Schlager, Daniel; Adams, Fabian; Benndorf, Matthias; Fritz, Benjamin; Langer, Mathias; Hesse, Albrecht; Schoenthaler, Martin; Neubauer, Jakob

2018-06-02

To validate AutoMated UroLithiasis Evaluation Tool (AMULET) software for kidney stone volumetry and compare its performance to standard clinical practice. Maximum diameter and volume of 96 urinary stones were measured as reference standard by three independent urologists. The same stones were positioned in an anthropomorphic phantom and CT scans acquired in standard settings. Three independent radiologists blinded to the reference values took manual measurements of the maximum diameter and automatic measurements of maximum diameter and volume. An "expected volume" was calculated based on manual diameter measurements using the formula: V=4/3 πr³. 96 stones were analyzed in the study. We had initially aimed to assess 100. Nine were replaced during data acquisition due of crumbling and 4 had to be excluded because the automated measurement did not work. Mean reference maximum diameter was 13.3 mm (5.2-32.1 mm). Correlation coefficients among all measured outcomes were compared. The correlation between the manual and automatic diameter measurements to the reference was 0.98 and 0.91, respectively (p<0.001). Mean reference volume was 1200 mm³ (10-9000 mm³). The correlation between the "expected volume" and automatically measured volume to the reference was 0.95 and 0.99, respectively (p<0.001). Patients' kidney stone burden is usually assessed according to maximum diameter. However, as most stones are not spherical, this entails a potential bias. Automated stone volumetry is possible and significantly more accurate than diameter-based volumetric calculations. To avoid bias in clinical trials, size should be measured as volume. However, automated diameter measurements are not as accurate as manual measurements.
Determination of Shapes of Boattail Bodies of Revolution for Minimum Wave Drag

NASA Technical Reports Server (NTRS)

Adams, Mac C.

1951-01-01

By use of an approximate equation for the wave drag of slender bodies of revolution in a supersonic flow field, the optimum shapes of certain boattail bodies are determined for minimum wave drag. The properties of three specific families of bodies are determined, the first family consisting of bodies having a given length and base area and a contour passing through a prescribed point between the nose and base, the second family having fixed length, base area, and maximum area, and the third family having given length, volume, and base area. The method presented is easily generalized to determine minimum-wave-drag profile shapes which have contours that must pass through any prescribed number of points. According to linearized theory, the optimum profiles are found to have infinite slope at the nose but zero radius of curvature so that the bodies appear to have pointed noses, a zero slope at the body base, and no variation of wave drag with Mach number. For those bodies having a specified intermediate.diameter (that is, location and magnitude given), the maximum body diameter is shown to be larger, in general, than the specified diameter. It is also shown that, for bodies having a specified maximum diameter, the location of the maximum diameter is not arbitrary but is determined from the ratio of base diameter to maximum diameter.
Blind deconvolution of astronomical images with band limitation determined by optical system parameters

NASA Astrophysics Data System (ADS)

Luo, L.; Fan, M.; Shen, M. Z.

2007-07-01

Atmospheric turbulence greatly limits the spatial resolution of astronomical images acquired by the large ground-based telescope. The record image obtained from telescope was thought as a convolution result of the object function and the point spread function. The statistic relationship of the images measured data, the estimated object and point spread function was in accord with the Bayes conditional probability distribution, and the maximum-likelihood formulation was found. A blind deconvolution approach based on the maximum-likelihood estimation technique with real optical band limitation constraint is presented for removing the effect of atmospheric turbulence on this class images through the minimization of the convolution error function by use of the conjugation gradient optimization algorithm. As a result, the object function and the point spread function could be estimated from a few record images at the same time by the blind deconvolution algorithm. According to the principle of Fourier optics, the relationship between the telescope optical system parameters and the image band constraint in the frequency domain was formulated during the image processing transformation between the spatial domain and the frequency domain. The convergence of the algorithm was increased by use of having the estimated function variable (also is the object function and the point spread function) nonnegative and the point-spread function band limited. Avoiding Fourier transform frequency components beyond the cut off frequency lost during the image processing transformation when the size of the sampled image data, image spatial domain and frequency domain were the same respectively, the detector element (e.g. a pixels in the CCD) should be less than the quarter of the diffraction speckle diameter of the telescope for acquiring the images on the focal plane. The proposed method can easily be applied to the case of wide field-view turbulent-degraded images restoration because of no using the object support constraint in the algorithm. The performance validity of the method is examined by the computer simulation and the restoration of the real Alpha Psc astronomical image data. The results suggest that the blind deconvolution with the real optical band constraint can remove the effect of the atmospheric turbulence on the observed images and the spatial resolution of the object image can arrive at or exceed the diffraction-limited level.
Comparison of Fluoroscopy and Computed Tomography for Tracheal Lumen Diameter Measurement and Determination of Intraluminal Stent Size in Healthy Dogs

PubMed Central

Williams, Jackie M.; Krebs, Ingar A.; Riedesel, Elizabeth A.; Zhao, Qianqian

2015-01-01

Tracheal collapse is a progressive airway disease that can ultimately result in complete airway obstruction. Intraluminal tracheal stents are a minimally invasive and viable treatment for tracheal collapse once the disease becomes refractory to medical management. Intraluminal stent size is chosen based on the maximum measured tracheal diameter during maximum inflation. The purpose of this prospective, cross-sectional study was to compare tracheal lumen diameter measurements and subsequent selected stent size using both fluoroscopy and CT and to evaluate inter- and intraobserver variability of the measurements. Seventeen healthy Beagles were anesthetized and imaged with fluoroscopy and CT with positive pressure ventilation to 20 cm H2O. Fluoroscopic and CT maximum tracheal diameters were measured by 3 readers. Three individual measurements were made at 8 pre-determined tracheal sites for dorsoventral (height) and laterolateral (width) dimensions. Tracheal diameters and stent sizes (based on the maximum tracheal diameter + 10%) were analyzed using a linear mixed model. CT tracheal lumen diameters were larger compared to fluoroscopy at all locations. When comparing modalities, fluoroscopic and CT stent sizes were statistically different. Greater overall variation in tracheal diameter measurement (height or width) existed for fluoroscopy compared to CT, both within and among observers. The greater tracheal diameter and lower measurement variability supported the use of CT for appropriate stent selection to minimize complications in veterinary patients. PMID:26784924
Apparatus and method for classifying fuel pellets for nuclear reactor

DOEpatents

Wilks, Robert S.; Sternheim, Eliezer; Breakey, Gerald A.; Sturges, Jr., Robert H.; Taleff, Alexander; Castner, Raymond P.

1984-01-01

Control for the operation of a mechanical handling and gauging system for nuclear fuel pellets. The pellets are inspected for diameters, lengths, surface flaws and weights in successive stations. The control includes, a computer for commanding the operation of the system and its electronics and for storing and processing the complex data derived at the required high rate. In measuring the diameter, the computer enables the measurement of a calibration pellet, stores that calibration data and computes and stores diameter-correction factors and their addresses along a pellet. To each diameter measurement a correction factor is applied at the appropriate address. The computer commands verification that all critical parts of the system and control are set for inspection and that each pellet is positioned for inspection. During each cycle of inspection, the measurement operation proceeds normally irrespective of whether or not a pellet is present in each station. If a pellet is not positioned in a station, a measurement is recorded, but the recorded measurement indicates maloperation. In measuring diameter and length a light pattern including successive shadows of slices transverse for diameter or longitudinal for length are projected on a photodiode array. The light pattern is scanned electronically by a train of pulses. The pulses are counted during the scan of the lighted diodes. For evaluation of diameter the maximum diameter count and the number of slices for which the diameter exceeds a predetermined minimum is determined. For acceptance, the maximum must be less than a maximum level and the minimum must exceed a set number. For evaluation of length, the maximum length is determined. For acceptance, the length must be within maximum and minimum limits.
The Effect of Connecting-passage Diameter on the Performance of a Compression-ignition Engine with a Precombustion Chamber

NASA Technical Reports Server (NTRS)

Moore, C S; Collins, J H

1932-01-01

Results of motoring tests are presented showing the effect of passage diameter on chamber and cylinder compression pressures, maximum pressure differences, and f.m.e.p. over a speed range from 300 to 1,750 r.p.m. Results of engine performance tests are presented which show the effect of passage diameter on m.e.p., explosion pressures, specific fuel consumption, and rates of pressure rise for a range of engine speeds from 500 to 1,500 r.p.m. The cylinder compression pressure, the maximum pressure difference, and the f.m.e.p. decreased rapidly as the passage diameter increased to 29/64 inch, whereas further increase in passage diameter effected only a slight change. The most suitable passage diameter for good engine performance and operating characteristics was 29/64 inch. Passage diameter became less critical with a decrease in engine speed. Therefore, the design should be based on maximum operating speed. Optimum performance and satisfactory combustion control could not be obtained by means of any single diameter of the connecting passage.

An analytical fiber bundle model for pullout mechanics of root bundles

NASA Astrophysics Data System (ADS)

Cohen, D.; Schwarz, M.; Or, D.

2011-09-01

Roots in soil contribute to the mechanical stability of slopes. Estimation of root reinforcement is challenging because roots form complex biological networks whose geometrical and mechanical characteristics are difficult to characterize. Here we describe an analytical model that builds on simple root descriptors to estimate root reinforcement. Root bundles are modeled as bundles of heterogeneous fibers pulled along their long axes neglecting root-soil friction. Analytical expressions for the pullout force as a function of displacement are derived. The maximum pullout force and corresponding critical displacement are either derived analytically or computed numerically. Key model inputs are a root diameter distribution (uniform, Weibull, or lognormal) and three empirical power law relations describing tensile strength, elastic modulus, and length of roots as functions of root diameter. When a root bundle with root tips anchored in the soil matrix is pulled by a rigid plate, a unique parameter, ?, that depends only on the exponents of the power law relations, dictates the order in which roots of different diameters break. If ? < 1, small roots break first; if ? > 1, large roots break first. When ? = 1, all fibers break simultaneously, and the maximum tensile force is simply the roots' mean force times the number of roots in the bundle. Based on measurements of root geometry and mechanical properties, the value of ? is less than 1, usually ranging between 0 and 0.7. Thus, small roots always fail first. The model shows how geometrical and mechanical characteristics of roots and root diameter distribution affect the pullout force, its maximum and corresponding displacement. Comparing bundles of roots that have similar mean diameters, a bundle with a narrow variance in root diameter will result in a larger maximum force and a smaller displacement at maximum force than a bundle with a wide diameter distribution. Increasing the mean root diameter of a bundle without changing the distribution's shape increases both the maximum force and corresponding displacement. Estimates of the maximum pullout forces for bundles of 100 roots with identical diameter distribution for different species range from less than 1 kN for barley (Hordeum vulgare) to almost 16 kN for pistachio (Pistacia lentiscus). The model explains why a commonly used assumption that all roots break simultaneously overpredicts the maximum pullout force by a factor of about 1.6-2. This ratio may exceed 3 for diameter distributions that have a large number of small roots like the exponential distribution.
Association of deep venous thrombosis with calf vein diameter in acute hemorrhagic stroke.

PubMed

Ogata, Toshiyasu; Yasaka, Masahiro; Wakugawa, Yoshiyuki; Kitazono, Takanari; Okada, Yasushi

2013-10-01

We investigated the association between the development of deep venous thrombosis (DVT) and calf vein diameter in patients with acute hemorrhagic stroke. We measured the maximum diameter of paralytic side posttibial veins (PTVs) and peroneal veins (PVs) in 49 patients with intracerebral hemorrhage on admission and at 2 weeks after stroke onset by ultrasonography. We also examined for the presence or absence of DVT, and then analyzed the association of DVT with the maximum vein diameter. At 2 weeks after stroke, DVTs were detected in PTVs in 7 patients and in PVs in 6 patients. The maximum calf vein diameters at 2 weeks were significantly greater in patients with DVT compared with those without DVT (PTV, P = .033; PV, P = .015). Although calf vein diameter at admission did not influence the future incidence of DVT in patients with intracerebral hemorrhage, the presence of DVT was associated with calf vein dilatation. Copyright © 2013 National Stroke Association. Published by Elsevier Inc. All rights reserved.
Spreading of an inkjet droplet on a solid surface with a controlled contact angle at low Weber and Reynolds numbers.

PubMed

Son, Yangsoo; Kim, Chongyoup; Yang, Doo Ho; Ahn, Dong June

2008-03-18

Even though the inkjet technology has been recognized as one of the most promising technologies for electronic and bio industries, the full understanding of the dynamics of an inkjet droplet at its operating conditions is still lacking. In this study, the normal impact of water droplets on solid substrates was investigated experimentally. The size of water droplets studied here was 46 microm and was much smaller than the most of the previous studies on drop impact. The Weber number (We) and Reynolds number (Re) were 0.05-2 and 10-100, respectively, and the Ohnesorge number was fixed at 0.017. The wettability of the solid substrate was varied by adsorbing a self-assembled monolayer of octadecyltrichlorosilane followed by the exposure to UV-ozone plasma. The impact scenarios for low We impacts were found to be qualitatively different from the high to moderate We impacts. Neither the development of a thin film and lamella under the traveling sphere nor the entrapment of small bubbles was observed. The dynamics of droplet impact at the conditions studied here is found to proceed under the combined influences of inertia, surface tension, and viscosity without being dominated by one specific mechanism. The maximum spreading factor (beta), the ratio of the diameter of the wetted surface and the drop diameter before impact, was correlated well with the relationship ln beta=0.090 ln We/(fs-cos theta)+0.151 for three decades of We/(fs-cos theta), where theta is the equilibrium contact angle, and fs is the ratio between the surface areas contacting the air and the solid substrate. The result implies that the final shape of the droplet is determined by the surface phenomenon rather than fluid mechanical effects.
Design of a k-space spectrometer for ultra-broad waveband spectral domain optical coherence tomography.

PubMed

Lan, Gongpu; Li, Guoqiang

2017-03-07

Nonlinear sampling of the interferograms in wavenumber (k) space degrades the depth-dependent signal sensitivity in conventional spectral domain optical coherence tomography (SD-OCT). Here we report a linear-in-wavenumber (k-space) spectrometer for an ultra-broad bandwidth (760 nm-920 nm) SD-OCT, whereby a combination of a grating and a prism serves as the dispersion group. Quantitative ray tracing is applied to optimize the linearity and minimize the optical path differences for the dispersed wavenumbers. Zemax simulation is used to fit the point spread functions to the rectangular shape of the pixels of the line-scan camera and to improve the pixel sampling rates. An experimental SD-OCT is built to test and compare the performance of the k-space spectrometer with that of a conventional one. Design results demonstrate that this k-space spectrometer can reduce the nonlinearity error in k-space from 14.86% to 0.47% (by approximately 30 times) compared to the conventional spectrometer. The 95% confidence interval for RMS diameters is 5.48 ± 1.76 μm-significantly smaller than both the pixel size (14 μm × 28 μm) and the Airy disc (25.82 μm in diameter, calculated at the wavenumber of 7.548 μm -1 ). Test results demonstrate that the fall-off curve from the k-space spectrometer exhibits much less decay (maximum as -5.20 dB) than the conventional spectrometer (maximum as -16.84 dB) over the whole imaging depth (2.2 mm).
Design of a k-space spectrometer for ultra-broad waveband spectral domain optical coherence tomography

NASA Astrophysics Data System (ADS)

Lan, Gongpu; Li, Guoqiang

2017-03-01

Nonlinear sampling of the interferograms in wavenumber (k) space degrades the depth-dependent signal sensitivity in conventional spectral domain optical coherence tomography (SD-OCT). Here we report a linear-in-wavenumber (k-space) spectrometer for an ultra-broad bandwidth (760 nm-920 nm) SD-OCT, whereby a combination of a grating and a prism serves as the dispersion group. Quantitative ray tracing is applied to optimize the linearity and minimize the optical path differences for the dispersed wavenumbers. Zemax simulation is used to fit the point spread functions to the rectangular shape of the pixels of the line-scan camera and to improve the pixel sampling rates. An experimental SD-OCT is built to test and compare the performance of the k-space spectrometer with that of a conventional one. Design results demonstrate that this k-space spectrometer can reduce the nonlinearity error in k-space from 14.86% to 0.47% (by approximately 30 times) compared to the conventional spectrometer. The 95% confidence interval for RMS diameters is 5.48 ± 1.76 μm—significantly smaller than both the pixel size (14 μm × 28 μm) and the Airy disc (25.82 μm in diameter, calculated at the wavenumber of 7.548 μm-1). Test results demonstrate that the fall-off curve from the k-space spectrometer exhibits much less decay (maximum as -5.20 dB) than the conventional spectrometer (maximum as -16.84 dB) over the whole imaging depth (2.2 mm).
Substrate Curvature Restricts Spreading and Induces Differentiation of Human Mesenchymal Stem Cells.

PubMed

Lee, Sang Joo; Yang, Shengyuan

2017-09-01

While cells attach, spread, migrate, proliferate, and differentiate in three-dimensional (3D) micromechanical environments, the mechanical factors of these environments influence the shapes, sizes, and adhesion forces of the cells. Here, the authors culture human mesenchymal stem cells (hMSCs) on a unique class of curvature-defined substrates, micro glass ball embedded polyacrylamide gels, prepared with an improved protocol, and investigate the spreading responses of the hMSCs on the glass balls to study the effects of substrate curvature on the spreading of hMSCs. The authors find that, among the used diameters of glass balls, the minimum diameter of a glass ball on which an hMSC can attach and spread is 500 μm. In contrast to the well-spread morphologies with randomly-multiple lamellipodia for the hMSCs growing on the flat glass plates, the morphologies of the hMSCs growing on the glass balls are almost uniformly spindle-shaped with two lamellipodia. The sensitivities of the attachment and spreading morphology of an hMSC to substrate curvature are very different from those of a fibroblast. The RT-PCR analysis reveals that the substrate curvature alone can induce adipogenesis of the hMSCs. These findings imply that substrate curvature has profound effects on stem cell behaviors, and detailed and in-depth studies on these effects and their underlying biophysical mechanisms are necessary. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
First Point-Spread Function and X-Ray Phase Contrast Imaging Results with an 88-mm Diameter Single Crystal

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

Lumpkin, A. H.; Garson, A. B.; Anastasio, M. A.

In this study, we report initial demonstrations of the use of single crystals in indirect x-ray imaging with a benchtop implementation of propagation-based (PB) x-ray phase contrast imaging. Based on single Gaussian peak fits to the x-ray images, we observed a four times smaller system point-spread function (PSF) with the 50-μm thick single crystal scintillators than with the reference polycrystalline phosphor/scintillator. Fiber-optic plate depth-of-focus and Al reflective-coating aspects are also elucidated. Guided by the results from the 25-mm diameter crystal samples, we report additionally the first results with a unique 88-mm diameter single crystal bonded to a fiber optic platemore » and coupled to the large format CCD. Both PSF and x-ray phase contrast imaging data are quantified and presented.« less
Anatomic characteristics of ruptured abdominal aortic aneurysm on conventional CT scans: Implications for rupture risk.

PubMed

Fillinger, Mark F; Racusin, Jessica; Baker, Robert K; Cronenwett, Jack L; Teutelink, Arno; Schermerhorn, Marc L; Zwolak, Robert M; Powell, Richard J; Walsh, Daniel B; Rzucidlo, Eva M

2004-06-01

The purpose of this study was to analyze anatomic characteristics of patients with ruptured abdominal aortic aneurysms (AAAs), with conventional two-dimensional computed tomography (CT), including comparison with control subjects matched for age, gender, and size. Records were reviewed to identify all CT scans obtained at Dartmouth-Hitchcock Medical Center or referring hospitals before emergency AAA repair performed because of rupture or acute severe pain (RUP group). CT scans obtained before elective AAA repair (ELEC group) were reviewed for age and gender match with patients in the RUP group. More than 40 variables were measured on each CT scan. Aneurysm diameter matching was achieved by consecutively deleting the largest RUP scan and the smallest ELEC scan to prevent bias. CT scans were analyzed for 259 patients with AAAs: 122 RUP and 137 ELEC. Patients were well matched for age, gender, and other demographic variables or risk factors. Maximum AAA diameter was significantly different in comparisons of all patients (RUP, 6.5 +/- 2 cm vs ELEC, 5.6 +/- 1 cm; P <.0001), and mean diameter of ruptured AAAs was 5 mm smaller in female patients (6.1 +/- 2 cm vs 6.6 +/- 2 cm; P =.007). Two hundred patients were matched for diameter, gender, and age (100 from each group; maximum AAA diameter, 6.0 +/- 1 cm vs 6.0 +/- 1 cm). Analysis of diameter-matched AAAs indicated that most variables were statistically similar in the two groups, including infrarenal neck length (17 +/- 1 mm vs 19 +/- 1 mm; P =.3), maximum thrombus thickness (25 +/- 1 mm vs 23 +/- 1 mm, P =.4), and indices of body habitus, such as [(maximum AAA diameter)/(normal suprarenal aorta diameter)] or [(maximum AAA diameter)/(L3 transverse diameter)]. Multivariate analysis controlling for gender indicated that the most significant variables for rupture were aortic tortuosity (odds ratio [OR] 3.3, indicating greater risk with no or mild tortuosity), diameter asymmetry (OR, 3.2 for a 1-cm difference in major-minor axis), and current smoking (OR, 2.7, with the greater risk in current smokers). When matched for age, gender, and diameter, ruptured AAAs tend to be less tortuous, yet have greater cross-sectional diameter asymmetry. On conventional two-dimensional CT axial sections, it appears that when diameter asymmetry is associated with low aortic tortuosity, the larger diameter on axial sections more accurately reflects rupture risk, and when diameter asymmetry is associated with moderate or severe aortic tortuosity, the smaller diameter on axial sections more accurately reflects rupture risk. Current smoking is significantly associated with rupture, even when controlling for gender and AAA anatomy.
Effects of maximum node degree on computer virus spreading in scale-free networks

NASA Astrophysics Data System (ADS)

Bamaarouf, O.; Ould Baba, A.; Lamzabi, S.; Rachadi, A.; Ez-Zahraouy, H.

2017-10-01

The increase of the use of the Internet networks favors the spread of viruses. In this paper, we studied the spread of viruses in the scale-free network with different topologies based on the Susceptible-Infected-External (SIE) model. It is found that the network structure influences the virus spreading. We have shown also that the nodes of high degree are more susceptible to infection than others. Furthermore, we have determined a critical maximum value of node degree (Kc), below which the network is more resistible and the computer virus cannot expand into the whole network. The influence of network size is also studied. We found that the network with low size is more effective to reduce the proportion of infected nodes.
Fire spread in chaparral -"go or no-go?"

Treesearch

D.R. Weise; Xiangyang Zhou; Lulu Sun; Shankar Mahalingam

2005-01-01

Current fire models are designed to model the spread of a linear fire front in dead, small-diameter fuels. Fires in predominantly living vegetation account for a large proportion of annual burned area nationally. Prescribed burning is used to manage living fuels; however, prescribed burning is currently conducted under conditions that result in marginal burning. We do...
High-speed ethanol micro-droplet impact on a solid surface

NASA Astrophysics Data System (ADS)

Fujita, Yuta; Kiyama, Akihito; Tagawa, Yoshiyuki

2016-11-01

Recently, droplet impact draws great attention in the fluid mechanics. In previous work, micro-droplet impact on a solid surface at velocities up to 100 m s-1 was studied. However the study was only on water micro-droplets. In this study, we experimentally investigate high-speed impact of ethanol micro-droplets in order to confirm the feature about maximum spreading radius with another liquid. A droplet is generated from a laser-induced high-speed liquid jet. The diameter of droplets is around 80 μm and the velocity is larger than 30 m s-1. The surface tension of ethanol is 22.4 mNm-1 and density is 789 kgm-3. Weber number ranges We >1000. By using a high-speed camera, we investigate the deformation of droplets as a function of Weber number. This work was supported by JSPS KAKENHI Grant Number JP26709007.
Wavelet-based algorithm to the evaluation of contrasted hepatocellular carcinoma in CT-images after transarterial chemoembolization.

PubMed

Alvarez, Matheus; de Pina, Diana Rodrigues; Romeiro, Fernando Gomes; Duarte, Sérgio Barbosa; Miranda, José Ricardo de Arruda

2014-07-26

Hepatocellular carcinoma is a primary tumor of the liver and involves different treatment modalities according to the tumor stage. After local therapies, the tumor evaluation is based on the mRECIST criteria, which involves the measurement of the maximum diameter of the viable lesion. This paper describes a computed methodology to measure through the contrasted area of the lesions the maximum diameter of the tumor by a computational algorithm. 63 computed tomography (CT) slices from 23 patients were assessed. Non-contrasted liver and HCC typical nodules were evaluated, and a virtual phantom was developed for this purpose. Optimization of the algorithm detection and quantification was made using the virtual phantom. After that, we compared the algorithm findings of maximum diameter of the target lesions against radiologist measures. Computed results of the maximum diameter are in good agreement with the results obtained by radiologist evaluation, indicating that the algorithm was able to detect properly the tumor limits. A comparison of the estimated maximum diameter by radiologist versus the algorithm revealed differences on the order of 0.25 cm for large-sized tumors (diameter > 5 cm), whereas agreement lesser than 1.0 cm was found for small-sized tumors. Differences between algorithm and radiologist measures were accurate for small-sized tumors with a trend to a small decrease for tumors greater than 5 cm. Therefore, traditional methods for measuring lesion diameter should be complemented non-subjective measurement methods, which would allow a more correct evaluation of the contrast-enhanced areas of HCC according to the mRECIST criteria.
The Effect of Magnetic Field on Positron Range and Spatial Resolution in an Integrated Whole-Body Time-Of-Flight PET/MRI System.

PubMed

Huang, Shih-Ying; Savic, Dragana; Yang, Jaewon; Shrestha, Uttam; Seo, Youngho

2014-11-01

Simultaneous imaging systems combining positron emission tomography (PET) and magnetic resonance imaging (MRI) have been actively investigated. A PET/MR imaging system (GE Healthcare) comprised of a time-of-flight (TOF) PET system utilizing silicon photomultipliers (SiPMs) and 3-tesla (3T) MRI was recently installed at our institution. The small-ring (60 cm diameter) TOF PET subsystem of this PET/MRI system can generate images with higher spatial resolution compared with conventional PET systems. We have examined theoretically and experimentally the effect of uniform magnetic fields on the spatial resolution for high-energy positron emitters. Positron emitters including 18 F, 124 I, and 68 Ga were simulated in water using the Geant4 Monte Carlo toolkit in the presence of a uniform magnetic field (0, 3, and 7 Tesla). The positron annihilation position was tracked to determine the 3D spatial distribution of the 511-keV gammy ray emission. The full-width at tenth maximum (FWTM) of the positron point spread function (PSF) was determined. Experimentally, 18 F and 68 Ga line source phantoms in air and water were imaged with an investigational PET/MRI system and a PET/CT system to investigate the effect of magnetic field on the spatial resolution of PET. The full-width half maximum (FWHM) of the line spread function (LSF) from the line source was determined as the system spatial resolution. Simulations and experimental results show that the in-plane spatial resolution was slightly improved at field strength as low as 3 Tesla, especially when resolving signal from high-energy positron emitters in the air-tissue boundary.
Particle tracking experiments in match-index-refraction porous media.

PubMed

Lachhab, Ahmed; Zhang, You-Kuan; Muste, Marian V I

2008-01-01

A low-cost, noninvasive, three-dimensional (3D), particle tracking velocimetry system was designed and built to investigate particle movement in match-index-refraction porous media. Both a uniform load of the glass beads of the same diameter and a binary load of the glass beads of two diameters were used. The purpose of the experiments is to study the effect of the two loads on the trajectories, velocity distribution, and spreading of small physical particles. A total of 35 particles were released and tracked in the uniform load and 46 in the binary load. The 3D trajectory of each particle was recorded with two video camcorders and analyzed. It is found that the particle's velocity, trajectory, and spreading are very sensitive to its initial location and that the smaller pore size or heterogeneity in the binary load increases the particles' velocity and enhances their spreading as compared with the uniform load. The experiments also verified the previous finding that the distribution of the particle velocities are lognormal in the longitudinal direction and Gaussian in two transverse directions and that the particle spreading is much larger along the longitudinal direction than along the traverse directions.
A semi-empirical model for the estimation of maximum horizontal displacement due to liquefaction-induced lateral spreading

USGS Publications Warehouse

Faris, Allison T.; Seed, Raymond B.; Kayen, Robert E.; Wu, Jiaer

2006-01-01

During the 1906 San Francisco Earthquake, liquefaction-induced lateral spreading and resultant ground displacements damaged bridges, buried utilities, and lifelines, conventional structures, and other developed works. This paper presents an improved engineering tool for the prediction of maximum displacement due to liquefaction-induced lateral spreading. A semi-empirical approach is employed, combining mechanistic understanding and data from laboratory testing with data and lessons from full-scale earthquake field case histories. The principle of strain potential index, based primary on correlation of cyclic simple shear laboratory testing results with in-situ Standard Penetration Test (SPT) results, is used as an index to characterized the deformation potential of soils after they liquefy. A Bayesian probabilistic approach is adopted for development of the final predictive model, in order to take fullest advantage of the data available and to deal with the inherent uncertainties intrinstiic to the back-analyses of field case histories. A case history from the 1906 San Francisco Earthquake is utilized to demonstrate the ability of the resultant semi-empirical model to estimate maximum horizontal displacement due to liquefaction-induced lateral spreading.
7 CFR 51.1995 - U.S. No. 1.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) Well formed; and, (2) Clean and bright. (3) Free from: (i) Blanks; and, (ii) Broken or split shells. (4... minimum diameter, minimum and maximum diameters, or in accordance with one of the size classifications in Table I. Table I Size classifications Maximum size—Will pass through a round opening of the following...
Observation of F region irregularities near a northern equatorial anomaly crest during solar minimum using ionosonde, GPS receiver, and satellites

NASA Astrophysics Data System (ADS)

Lee, C.-C.; Chen, W. S.; Chu, F. D.

2013-06-01

For solar minimum, the spread F, GPS phase fluctuations, and plasma bubbles near the crest of equatorial ionization anomaly (EIA) are simultaneously analyzed to investigate F region irregularities for the first time. The data were observed using the Chungli ionosonde, YMSM GPS receiver, and DMSP satellites during 1996. It is found that in the observed ionograms, the frequency spread F (FSF) usually comes after the range spread F (RSF) in a series of nighttime spread F events. This results in that the maximum occurrence of RSF appears before that of FSF in the nighttime variations in occurrence probabilities. Moreover, the seasonal variation for RSF is close to that for FSF. Both have a board maximum in the J-months and a secondary maximum in December. These indicate that RSF and FSF should be regarded as one type of spread F, which is the all spread F (ASF) in this study. Because the equatorial plasma bubbles occur infrequently during solar minimum, the F region irregularities forming ASF are not related to the equatorial spread F. On the other hand, the similarity in seasonal occurrence between ASF and medium-scale traveling ionospheric disturbances (MSTIDs) demonstrates that the F region irregularities near the EIA crest are mainly generated by the gradient drift instability driven by MSTIDs. The irregularities, generated by MSTIDs, mostly occur in the bottom side of the F region. Consequently, the events of significant GPS phase fluctuations and plasma bubble near the EIA crest are rare during 1996.
Design of a k-space spectrometer for ultra-broad waveband spectral domain optical coherence tomography

PubMed Central

Lan, Gongpu; Li, Guoqiang

2017-01-01

Nonlinear sampling of the interferograms in wavenumber (k) space degrades the depth-dependent signal sensitivity in conventional spectral domain optical coherence tomography (SD-OCT). Here we report a linear-in-wavenumber (k-space) spectrometer for an ultra-broad bandwidth (760 nm–920 nm) SD-OCT, whereby a combination of a grating and a prism serves as the dispersion group. Quantitative ray tracing is applied to optimize the linearity and minimize the optical path differences for the dispersed wavenumbers. Zemax simulation is used to fit the point spread functions to the rectangular shape of the pixels of the line-scan camera and to improve the pixel sampling rates. An experimental SD-OCT is built to test and compare the performance of the k-space spectrometer with that of a conventional one. Design results demonstrate that this k-space spectrometer can reduce the nonlinearity error in k-space from 14.86% to 0.47% (by approximately 30 times) compared to the conventional spectrometer. The 95% confidence interval for RMS diameters is 5.48 ± 1.76 μm—significantly smaller than both the pixel size (14 μm × 28 μm) and the Airy disc (25.82 μm in diameter, calculated at the wavenumber of 7.548 μm−1). Test results demonstrate that the fall-off curve from the k-space spectrometer exhibits much less decay (maximum as −5.20 dB) than the conventional spectrometer (maximum as –16.84 dB) over the whole imaging depth (2.2 mm). PMID:28266502
The Fogging Method with Variable of Nozle Diameter as the Mitigation Alternative for Spreading the Dust of Cement

NASA Astrophysics Data System (ADS)

Purwanta, J.; Marnoto, T.; Setyono, P.; Ramelan, A. H.

2018-03-01

The cement plant impacts on the lives of people around the factory site, one of them on the air quality, especially dust. Cement plant has made various efforts to mitigate dust generated, but the reality on the ground is still a lot of dust flying around either of the cement factory chimneys and transportation. The purpose of this study was to find the optimum condition of nozle diameter from the cement dust catcher, for mitigation the dust spread to around the cement plant. This study uses research methods such as collecting secondary data which includes data intensity rainfall, the average long rains, wind speed and direction as well as data quality monitoring dust around PT. Semen Gresik (Persero) Tbk. Tuban plant. To determine the wind direction propensity models, use a soft Windrose file. To determine the impact on the spread of dust into the environment using secondary data monitoring air quality. Results of the study is that the mitigation of dust around the cement plant is influenced by natural factors, namely the tendency of wind direction, rainfall and rainy days, and the rate of dust emission from the chimney. I try for operate the cement dust catcher with variable of nozle diameter. Finally, I find the optimum condition of nozle diameter for cement dust catcher is 1.40 mm, with line equation is y = 149.09.e 1.6237.x and error 5%. In that condition, nozle can make the fog with a good quality and it can catch the cement dust well.
Wind tunnel investigation of three axisymmetric cowls of different lengths at Mach numbers from 0.60 to 0.92

NASA Technical Reports Server (NTRS)

Re, Richard J.; Abeyounis, William K.

1993-01-01

Pressure distributions on three inlets having different cowl lengths were obtained in the Langley 16-Foot Transonic Tunnel. The cowl diameter ratio (highlight diameter to maximum diameter) was 0.85 and the cowl length ratios (cowl length to maximum diameter) were 0.337, 0.439, and 0.547. The cowls had identical nondimensionalized (with respect to cowl length) external geometry and identical internal geometry. The internal contraction ratio (highlight area to throat area) was 1.250. The inlets had longitudinal rows of static pressure orifices on the top and bottom (external) surfaces and on the contraction (internal) and diffuser surfaces. The afterbody was cylindrical in shape, and its diameter was equal to the maximum diameter of the cowl. Depending on the cowl configuration and free-stream Mach number, the mass-flow ratio varied between 0.27 and 0.87 during the tests. Angle of attack varied from 0 to 4.1 deg at selected Mach numbers and mass-flow ratios, and the Reynolds number varied with the Mach number from 3.2x10(exp 6) to 4.2x10(exp 6) per foot.

Ionospheric modification - An initial report on artificially created equatorial Spread F

NASA Technical Reports Server (NTRS)

Ossakow, S. L.; Zalesak, S. T.; Mcdonald, B. E.

1978-01-01

A numerical simulation code for investigating equatorial Spread F in the collisional Rayleigh-Taylor regime is utilized to follow the evolution of artificial plasma density depletions injected into the bottomside nighttime equatorial F region. The 70 km diameter hole rapidly rises and steepens, forming plasma density enhancements at altitudes below the rising hole. The distribution of enhancements and depletions is similar to natural equatorial Spread F phenomena, except it occurs on a much faster time scale. These predictions warrant carrying out artificial injection experiments in the nighttime equatorial F region.
Novel Maximum-based Timing Acquisition for Spread-Spectrum Communications

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

Sibbetty, Taylor; Moradiz, Hussein; Farhang-Boroujeny, Behrouz

This paper proposes and analyzes a new packet detection and timing acquisition method for spread spectrum systems. The proposed method provides an enhancement over the typical thresholding techniques that have been proposed for direct sequence spread spectrum (DS-SS). The effective implementation of thresholding methods typically require accurate knowledge of the received signal-to-noise ratio (SNR), which is particularly difficult to estimate in spread spectrum systems. Instead, we propose a method which utilizes a consistency metric of the location of maximum samples at the output of a filter matched to the spread spectrum waveform to achieve acquisition, and does not require knowledgemore » of the received SNR. Through theoretical study, we show that the proposed method offers a low probability of missed detection over a large range of SNR with a corresponding probability of false alarm far lower than other methods. Computer simulations that corroborate our theoretical results are also presented. Although our work here has been motivated by our previous study of a filter bank multicarrier spread-spectrum (FB-MC-SS) system, the proposed method is applicable to DS-SS systems as well.« less
Experimental and numerical investigations of heat transfer and thermal efficiency of an infrared gas stove

NASA Astrophysics Data System (ADS)

Charoenlerdchanya, A.; Rattanadecho, P.; Keangin, P.

2018-01-01

An infrared gas stove is a low-pressure gas stove type and it has higher thermal efficiency than the other domestic cooking stoves. This study considers the computationally determine water and air temperature distributions, water and air velocity distributions and thermal efficiency of the infrared gas stove. The goal of this work is to investigate the effect of various pot diameters i.e. 220 mm, 240 mm and 260 mm on the water and air temperature distributions, water and air velocity distributions and thermal efficiency of the infrared gas stove. The time-dependent heat transfer equation involving diffusion and convection coupled with the time-dependent fluid dynamic equation is implemented and is solved by using the finite element method (FEM). The computer simulation study is validated with an experimental study, which is use standard experiment by LPG test for low-pressure gas stove in households (TIS No. 2312-2549). The findings revealed that the water and air temperature distributions increase with greater heating time, which varies with the three different pot diameters (220 mm, 240 mm and 260 mm). Similarly, the greater heating time, the water and air velocity distributions increase that vary by pot diameters (220, 240 and 260 mm). The maximum water temperature in the case of pot diameter of 220 mm is higher than the maximum water velocity in the case of pot diameters of 240 mm and 260 mm, respectively. However, the maximum air temperature in the case of pot diameter of 260 mm is higher than the maximum water velocity in the case of pot diameters of 240 mm and 220 mm, respectively. The obtained results may provide a basis for improving the energy efficiency of infrared gas stoves and other equipment, including helping to reduce energy consumption.
A continuously variable beam-diameter, high-fluence, Q-switched Nd:YAG laser for tattoo removal: comparison of the maximum beam diameter to a standard 4-mm-diameter treatment beam.

PubMed

Bernstein, Eric F; Civiok, Jennifer M

2013-12-01

Laser beam diameter affects the depth of laser penetration. Q-switched lasers tend to have smaller maximum spot sizes than other dermatologic lasers, making beam diameter a potentially more significant factor in treatment outcomes. To compare the clinical effect of using the maximum-size treatment beam available for each delivered fluence during laser tattoo removal to a standard 4-mm-diameter treatment beam. Thirteen tattoos were treated in 12 subjects using a Q-switched Nd:YAG laser equipped with a treatment beam diameter that was adjustable in 1 mm increments and a setting that would enable the maximally achievable diameter ("MAX-ON" setting) with any fluence. Tattoos were randomly bisected and treated on one side with the MAX-ON setting and on the contralateral side with a standard 4-mm-diameter spot ("MAX-OFF" setting). Photographs were taken 8 weeks following each treatment and each half-tattoo was evaluated for clearance on a 10-point scale by physicians blinded to the treatment conditions. Tattoo clearance was greater on the side treated with the MAX-ON setting in a statistically significant manner following the 1st through 4th treatments, with the MAX-OFF treatment site approaching the clearance of the MAX-ON treatment site after the 5th and 6th treatments. This high-energy, Q-switched Nd:YAG laser with a continuously variable spot-size safely and effectively removes tattoos, with greater removal when using a larger spot-size. © 2013 Wiley Periodicals, Inc.
Reproduction of the giant jellyfish, Nemopilema nomurai (Scyphozoa: Rhizostomeae), in 2006-2008 as peripherally-transported populations

NASA Astrophysics Data System (ADS)

Iguchi, Naoki; Lee, Hye Eun; Yoon, Won Duk; Kim, Suam

2010-06-01

This study investigated the sexual maturation process, release of spermatozoa or eggs and oocyte diameter of the rhizostomid medusae Nemopilema nomurai using samples collected from August 2006 to June 2008 from the waters around Korea and Japan, including peripheral areas outside the species’ usual habitat. Immature medusae were observed from June to October only in the western sector of the study area. The onset of spermatozoa and egg release occurred in September and October, respectively, and peaked in December and January. Medusae migrated eastward from source areas with the Tsushima Warm Current, where they formed gametes and spawned. Peak position and maximum oocyte diameter increased as the gonads developed according to the size-frequency distribution of oocytes. No fertilized eggs or embryos were found in the gonads. The correlation was analyzed with bell diameter, maximum oocyte diameter, sampling date, surface water temperature and gonad color to estimate which environmental factors and maturation indices were related to the maturation stage of females. Maturation stage correlated well with maximum oocyte diameter, which correlated negatively with surface water temperature. There was no significant correlation between bell diameter and maturation stage. Therefore, bell diameter was inappropriate for determining maturation index. Sex could not be distinguished clearly by gonad color. However, light pink gonads were more prevalent in males and various deep colors such as orange and brown were more frequent in female medusae.
Optimizing Hybrid Spreading in Metapopulations

PubMed Central

Zhang, Changwang; Zhou, Shi; Miller, Joel C.; Cox, Ingemar J.; Chain, Benjamin M.

2015-01-01

Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by local spreading, where infected nodes can only infect a limited set of direct target nodes and global spreading, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemics, and examine the optimum balance between spreading mechanisms in terms of achieving the maximum outbreak size. We show the existence of critically hybrid epidemics where neither spreading mechanism alone can cause a noticeable spread but a combination of the two spreading mechanisms would produce an enormous outbreak. Our results provide new strategies for maximising beneficial epidemics and estimating the worst outcome of damaging hybrid epidemics. PMID:25923411
Optimizing hybrid spreading in metapopulations.

PubMed

Zhang, Changwang; Zhou, Shi; Miller, Joel C; Cox, Ingemar J; Chain, Benjamin M

2015-04-29

Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by local spreading, where infected nodes can only infect a limited set of direct target nodes and global spreading, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemics, and examine the optimum balance between spreading mechanisms in terms of achieving the maximum outbreak size. We show the existence of critically hybrid epidemics where neither spreading mechanism alone can cause a noticeable spread but a combination of the two spreading mechanisms would produce an enormous outbreak. Our results provide new strategies for maximising beneficial epidemics and estimating the worst outcome of damaging hybrid epidemics.
Angle-resolved reflection spectroscopy of high-quality PMMA opal crystal

NASA Astrophysics Data System (ADS)

Nemtsev, Ivan V.; Tambasov, Igor A.; Ivanenko, Alexander A.; Zyryanov, Victor Ya.

2018-02-01

PMMA opal crystal was prepared by a simple hybrid method, which includes sedimentation, meniscus formation and evaporation. We investigated three surfaces of this crystal by angle-resolved reflective light spectroscopy and SEM study. The angle-resolved reflective measurements were carried out in the 400-1100 nm range. We have determined the high-quality ordered surface of the crystal region. Narrow particle size distribution of the surface has been revealed. The average particle diameter obtained with SEM was nearly 361 nm. The most interesting result was that reflectivity of the surface turned out up to 98% at normal light incidence. Using a fit of dependences of the maximum reflectivity wavelength from an angle based on the Bragg-Snell law, the wavelength of maximum 0° reflectivity, the particle diameter and the fill factor have been determined. For the best surface maximum reflectivity wavelength of a 0° angle was estimated to be 869 nm. The particle diameter and fill factor were calculated as 372 nm and 0.8715, respectively. The diameter obtained by fitting is in excellent agreement with the particle diameter obtained with SEM. The reflectivity maximum is assumed to increase significantly when increasing the fill factor. We believe that using our simple approach to manufacture PMMA opal crystals will significantly increase the fabrication of high-quality photonic crystal templates and thin films.
Classification of Kiwifruit Grades Based on Fruit Shape Using a Single Camera

PubMed Central

Fu, Longsheng; Sun, Shipeng; Li, Rui; Wang, Shaojin

2016-01-01

This study aims to demonstrate the feasibility for classifying kiwifruit into shape grades by adding a single camera to current Chinese sorting lines equipped with weight sensors. Image processing methods are employed to calculate fruit length, maximum diameter of the equatorial section, and projected area. A stepwise multiple linear regression method is applied to select significant variables for predicting minimum diameter of the equatorial section and volume and to establish corresponding estimation models. Results show that length, maximum diameter of the equatorial section and weight are selected to predict the minimum diameter of the equatorial section, with the coefficient of determination of only 0.82 when compared to manual measurements. Weight and length are then selected to estimate the volume, which is in good agreement with the measured one with the coefficient of determination of 0.98. Fruit classification based on the estimated minimum diameter of the equatorial section achieves a low success rate of 84.6%, which is significantly improved using a linear combination of the length/maximum diameter of the equatorial section and projected area/length ratios, reaching 98.3%. Thus, it is possible for Chinese kiwifruit sorting lines to reach international standards of grading kiwifruit on fruit shape classification by adding a single camera. PMID:27376292
Human Cough as a Two-Stage Jet and Its Role in Particle Transport

PubMed Central

Li, Yuguo

2017-01-01

The human cough is a significant vector in the transmission of respiratory diseases in indoor environments. The cough flow is characterized as a two-stage jet; specifically, the starting jet (when the cough starts and flow is released) and interrupted jet (after the source supply is terminated). During the starting-jet stage, the flow rate is a function of time; three temporal profiles of the exit velocity (pulsation, sinusoidal and real-cough) were investigated in this study, and our results showed that the cough flow’s maximum penetration distance was in the range of a 50.6–85.5 opening diameter (D) under our experimental conditions. The real-cough and sinusoidal cases exhibited greater penetration ability than the pulsation cases under the same characteristic Reynolds number (Rec) and normalized cough expired volume (Q/AD, with Q as the cough expired volume and A as the opening area). However, the effects of Rec and Q/AD on the maximum penetration distances proved to be more significant; larger values of Rec and Q/AD reflected cough flows with greater penetration distances. A protocol was developed to scale the particle experiments between the prototype in air, and the model in water. The water tank experiments revealed that although medium and large particles deposit readily, their maximum spread distance is similar to that of small particles. Moreover, the leading vortex plays an important role in enhancing particle transport. PMID:28046084
The Effects of Angular Orientation on Flame Spread over Thin Materials

DTIC Science & Technology

1999-12-01

Notation 7 5 Upward Spread With Burnout 8 6a Observed Flame Lengths on Napkins, Increments 2.5 cm 9 6b Observed Flame Lengths on Pet Film, Increments...Frequency of Extinguishment During Flame Spread 21 15 Flame Spread Velocity 21 VI 16 Flame Length Measured Parallel to the Surface 22 17 Comparison of... flame length (Lf) were measured from a video recording of the test. Despite erratic burn fronts with discontinuous flaming regions, the maximum
Jet Spreading Increase by Passive Control and Associated Performance Penalty

NASA Technical Reports Server (NTRS)

Zaman, K. B. M. Q.

1999-01-01

This paper reviews the effects of 'screech', 'asymmetric nozzle shaping', 'tabs' and 'overexpansion' on the spreading of free jets. Corresponding thrust penalty for the tabs and overexpanded condition are also evaluated. The asymmetric shapes include rectangular ones with varying aspect ratio. Tabs investigated are triangular shaped 'delta-tabs' placed at the exit of a convergent circular nozzle. The effect of overexpansion is examined with circular convergent-divergent (C-D) nozzles. Tabs and overexpansion are found to yield the largest increase in jet spreading. Each, however, involves a performance penalty, i.e., a loss in thrust coefficient. Variation of the size of four delta-tabs show that there exists an optimum size for which the gain in jet spreading is the maximum per unit loss in thrust coefficient. With the C-D nozzles, the minimum in thrust coefficient is expected near the beginning of the overexpanded regime based on idealized flow calculations. The maximum increase in jet spreading, however, is found to occur at higher pressure ratios well into the overexpanded regime. The optimum benefit with the overexpanded flow, in terms of gain in spreading for unit penalty, is found to be comparable to the optimum tab case.
Phospholipids as an alternative to direct covalent coupling: surface functionalization of nanoporous alumina for protein recognition and purification.

PubMed

Lazzara, Thomas D; Behn, Daniela; Kliesch, Torben-Tobias; Janshoff, Andreas; Steinem, Claudia

2012-01-15

Anodic aluminum oxide (AAO) substrates with aligned, cylindrical, non-intersecting pores with diameters of 75 nm and depths of 3.5 or 10 μm were functionalized with lipid monolayers harboring different receptor lipids. AAO was first functionalized with dodecyl-trichlorosilane, followed by fusion of small unilamellar vesicles (SUVs) forming a lipid monolayer. The SUVs' lipid composition was transferred onto the AAO surface, allowing us to control the surface receptor density. Owing to the optical transparency of the AAO, the overall vesicle spreading process and subsequent protein binding to the receptor-doped lipid monolayers could be investigated in situ by optical waveguide spectroscopy (OWS). SUV spreading occurred at the pore-rim interface, followed by lateral diffusion of lipids within the pore-interior surface until homogeneous coverage was achieved with a lipid monolayer. The functionality of the system was demonstrated through streptavidin binding onto a biotin-DOPE containing POPC membrane, showing maximum protein coverage at 10 mol% of biotin-DOPE. The system enabled us to monitor in real-time the selective extraction of two histidine-tagged proteins, PIGEA14 (14 kDa) and ezrin (70 kDa), directly from cell lysate solutions using a DOGS-NTA(Ni)/DOPC (1:9) membrane. The purification process including protein binding and elution was monitored by OWS and confirmed by SDS-PAGE. Copyright Â© 2011 Elsevier Inc. All rights reserved.
Spread of cochlear excitation during stimulation with pulsed infrared radiation: inferior colliculus measurements

NASA Astrophysics Data System (ADS)

Richter, C.-P.; Rajguru, S. M.; Matic, A. I.; Moreno, E. L.; Fishman, A. J.; Robinson, A. M.; Suh, E.; Walsh, J. T., Jr.

2011-10-01

Infrared neural stimulation (INS) has received considerable attention over the last few years. It provides an alternative method to artificially stimulate neurons without electrical current or the introduction of exogenous chromophores. One of the primary benefits of INS could be the improved spatial selectivity when compared with electrical stimulation. In the present study, we have evaluated the spatial selectivity of INS in the acutely damaged cochlea of guinea pigs and compared it to stimulation with acoustic tone pips in normal-hearing animals. The radiation was delivered via a 200 µm diameter optical fiber, which was inserted through a cochleostomy into the scala tympani of the basal cochlear turn. The stimulated section along the cochlear spiral ganglion was estimated from the neural responses recorded from the central nucleus of the inferior colliculus (ICC). ICC responses were recorded in response to cochlear INS using a multichannel penetrating electrode array. Spatial tuning curves (STCs) were constructed from the responses. For INS, approximately 55% of the activation profiles showed a single maximum, ~22% had two maxima and ~13% had multiple maxima. The remaining 10% of the profiles occurred at the limits of the electrode array and could not be classified. The majority of ICC STCs indicated that the spread of activation evoked by optical stimuli is comparable to that produced by acoustic tone pips.
Emergence of two lamellas during impact of compound droplets

NASA Astrophysics Data System (ADS)

Liu, Dongdong; Tran, Tuan

2018-05-01

A compound droplet consisting of water and silicone oil either spreads or splashes upon impacting a solid surface. We show that the transition from spreading to splashing of this type of compound droplet can be changed by varying the volumetric oil ratio in the droplets. In the spreading regime, we observe a surprising emergence of two lamellas spreading one after the other: the first spreading lamella consists of only oil and the trailing one water. We show that the two lamellas eventually meet, significantly affecting the spreading dynamics. Finally, we quantify the maximum spreading radius and show that it is a function of both the impact velocity and the volumetric oil ratio.
Characterization of copper and nichrome wires for safety fuse

NASA Astrophysics Data System (ADS)

Murdani, E.

2016-11-01

Fuse is an important component of an electrical circuit to limiting the current through the electrical circuit for electrical equipment safety. Safety fuses are made of a conductor such as copper and nichrome wires. The aim of this research was to determine the maximum current that can flow in the conductor wires (copper and nichrome). In the experiment used copper and nichrome wires by varying the length of wires (0.2 cm to 20 cm) and diameter of wires (0.1, 0.2, 0.3, 0.4 and 0.5) mm until maximum current reached that marked by melted or broken wire. From this experiment, it will be obtained the dependences data of maximum current to the length and diameter of wires. All data are plotted and it's known as a standard curve. The standard curve will provide an alternative choice of replacing fuse wire according to the maximum current requirement, including the wire type (copper and nichrome wires) and wire dimensions (length and diameter of wire).
2007 Global Demilitarization Symposium and Exhibition

DTIC Science & Technology

2007-05-17

system! Defines reactive properties ! www.biorex.se Heavy metals • Water soluble • Easily spread • Elements • Not degradable • Hazardous • In high or low...Activated sludge Oat by-products Juniper fibre Sawdust Agro-based fibres Seaweed Grape stalk fibres Marine algae Husk of black gram www.biorex.se Sorbent...Description Reactor Illustration 18 inch diameter reactor 120 inches high Single diameter throughout entire reactor length 19 resistance heaters Alloy 600
Dose calculation for electron therapy using an improved LBR method.

PubMed

Gebreamlak, Wondesen T; Tedeschi, David J; Alkhatib, Hassaan A

2013-07-01

To calculate the percentage depth dose (PDD) of any irregularly shaped electron beam using a modified lateral build-up ratio (LBR) method. Percentage depth dose curves were measured using 6, 9, 12, and 15 MeV electron beam energies for applicator cone sizes of 6 × 6, 10 × 10, 14 × 14, and 20 × 20 cm(2). Circular cutouts for each cone were prepared from 2.0 cm diameter to the maximum possible size for each cone. In addition, three irregular cutouts were prepared. The LBR for each circular cutout was calculated from the measured PDD curve using the open field of the 14 × 14 cm(2) cone as the reference field. Using the LBR values and the radius of the circular cutouts, the corresponding lateral spread parameter [σR(z)] of the electron shower was calculated. Unlike the commonly accepted assumption that σR(z) is independent of cutout size, it is shown that its value increases linearly with circular cutout size (R). Using this characteristic of the lateral spread parameter, the PDD curves of irregularly shaped cutouts were calculated. Finally, the calculated PDD curves were compared with measured PDD curves. In this research, it is shown that the lateral spread parameter σR(z) increases with cutout size. For radii of circular cutout sizes up to the equilibrium range of the electron beam, the increase of σR(z) with the cutout size is linear. The percentage difference of the calculated PDD curve from the measured PDD data for irregularly shaped cutouts was under 1.0% in the region between the surface and therapeutic range of the electron beam. Similar results were obtained for four electron beam energies (6, 9, 12, and 15 MeV).
Morphological alterations of T24 cells on flat and nanotubular TiO2 surfaces.

PubMed

Imani, Roghayeh; Kabaso, Doron; Erdani Kreft, Mateja; Gongadze, Ekaterina; Penic, Samo; Elersic, Kristina; Kos, Andrej; Veranic, Peter; Zorec, Robert; Iglic, Ales

2012-12-01

To investigate morphological alterations of malignant cancer cells (T24) of urothelial origin seeded on flat titanium (Ti) and nanotubular TiO(2) (titanium dioxide) nanostructures. Using anodization method, TiO(2) surfaces composed of vertically aligned nanotubes of 50-100 nm diameters were produced. The flat Ti surface was used as a reference. The alteration in the morphology of cancer cells was evaluated using scanning electron microscopy (SEM). A computational model, based on the theory of membrane elasticity, was constructed to shed light on the biophysical mechanisms responsible for the observed changes in the contact area of adhesion. Large diameter TiO(2) nanotubes exhibited a significantly smaller contact area of adhesion (P<0.0001) and had more membrane protrusions (eg, microvilli and intercellular membrane nanotubes) than on flat Ti surface. Numerical membrane dynamics simulations revealed that the low adhesion energy per unit area would hinder the cell spreading on the large diameter TiO(2) nanotubular surface, thus explaining the small contact area. The reduction in the cell contact area in the case of large diameter TiO(2) nanotube surface, which does not enable formation of the large enough number of the focal adhesion points, prevents spreading of urothelial cells.
Impact of viscous droplets on different wettable surfaces: Impact phenomena, the maximum spreading factor, spreading time and post-impact oscillation.

PubMed

Lin, Shiji; Zhao, Binyu; Zou, Song; Guo, Jianwei; Wei, Zheng; Chen, Longquan

2018-04-15

In this paper, we experimentally investigated the impact dynamics of different viscous droplets on solid surfaces with diverse wettabilities. We show that the outcome of an impinging droplet is dependent on the physical property of the droplet and the wettability of the surface. Whereas only deposition was observed on lyophilic surfaces, more impact phenomena were identified on lyophobic and superlyophobic surfaces. It was found that none of the existing theoretical models can well describe the maximum spreading factor, revealing the complexity of the droplet impact dynamics and suggesting that more factors need to be considered in the theory. By using the modified capillary-inertial time, which considers the effects of liquid viscosity and surface wettability on droplet spreading, a universal scaling law describing the spreading time was obtained. Finally, we analyzed the post-impact droplet oscillation with the theory for damped harmonic oscillators and interpreted the effects of liquid viscosity and surface wettability on the oscillation by simple scaling analyses. Copyright © 2017 Elsevier Inc. All rights reserved.

The Imaging Properties of a Silicon Wafer X-Ray Telescope

NASA Technical Reports Server (NTRS)

Joy, M. K.; Kolodziejczak, J. J.; Weisskopf, M. C.; Fair, S.; Ramsey, B. D.

1994-01-01

Silicon wafers have excellent optical properties --- low microroughness and good medium-scale flatness --- which Make them suitable candidates for inexpensive flat-plate grazing-incidence x-ray mirrors. On short spatial scales (less than 3 mm) the surface quality of silicon wafers rivals that expected of the Advanced X-Ray Astrophysics Facility (AXAF) high-resolution optics. On larger spatial scales, however, performance may be degraded by the departure from flatness of the wafer and by distortions induced by the mounting scheme. In order to investigate such effects, we designed and constructed a prototype silicon-wafer x-ray telescope. The device was then tested in both visible light and x rays. The telescope module consists of 94 150-mm-diameter wafers, densely packed into the first stage of a Kirkpatrick-Baez configuration. X-ray tests at three energies (4.5, 6.4, and 8.0 keV) showed an energy-independent line spread function with full width at half maximum (FWHM) of 150 arcseconds, dominated by deviations from large-scale flatness.
An investigation of flame spread over shallow liquid pools in microgravity and nonair environments

NASA Technical Reports Server (NTRS)

Ross, Howard D.; Sotos, Raymond G.

1991-01-01

Experiments of interest to combustion fundamentals and spacecraft fire safety investigated flame spread of alcohol fuels over shallow, 15 cm diameter pools in a 5.2 sec free-fall, microgravity facility. Results showed that, independent O2 concentrations, alcohol fuel, and diluent types, microgravity flame spread rates were nearly identical to those corresponding normal-gravity flames for conditions where the normal gravity flames spread uniformly. This similarity indicated buoyancy-related convection in either phase does not affect flame spread, at least for the physical scale of the experiments. However, microgravity extinction coincided with the onset conditions for pulsating spread in normal gravity, implicating gas phase, buoyant flow as a requirement for pulsating spread. When the atmospheric nitrogen was replaced with argon, the conditions for the onset of normal-gravity pulsating flame spread and microgravity flame extinction were changed, in agreement with the expected lowering of the flash point through the thermal properties of the diluent. Helium-diluted flames, however, showed unexpected results with a shift to apparently higher flash-point temperatures and high normal gravity pulsation amplitudes.
An Investigation of Flame Spread over Shallow Liquid Pools in Microgravity and Nonair Environments

NASA Technical Reports Server (NTRS)

Ross, Howard D.; Sotos, Raymond G.

1989-01-01

Experiments of interest to combustion fundamentals and spacecraft fire safety investigated flame spread of alcohol fuels over shallow, 15 cm diameter pools in a 5.2 sec free-fall, microgravity facility. Results showed that, independent O2 concentration, alcohol fuel, and diluent types, microgravity flame spread rates were nearly identical to those corresponding normal-gravity flames for conditions where the normal gravity flames spread uniformly. This similarity indicated buoyancy-related convection in either phase does not affect flame spread, at least for the physical scale of the experiments. However, microgravity extinction coincided with the onset conditions for pulsating spread in normal gravity, implicating gas phase, buoyant flow as a requirement for pulsating spread. When the atmospheric nitrogen was replaced with argon, the conditions for the onset of normal-gravity pulsating flame spread and microgravity flame extinction were changed, in agreement with the expected lowering of the flash point through the thermal properties of the diluent. Helium-diluted flames, however, showed unexpected results with a shift to apparently higher flash-point temperatures and high normal gravity pulsation amplitudes.
Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars

PubMed Central

Abarca, J.; Zaror, C.; Monardes, H.; Hermosilla, V.; Muñoz, C.; Cantin, M.

2015-01-01

SUMMARY Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3–5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24–0.33 mm in maxillary first molars and between 0.25–0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully. PMID:25937698
Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars.

PubMed

Abarca, J; Zaror, C; Monardes, H; Hermosilla, V; Muñoz, C; Cantin, M

2014-06-01

Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3-5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24-0.33 mm in maxillary first molars and between 0.25-0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully.
Some dynamics of spread and infection by aeciospores of Puccinia punctiformis, a biological control pathogen of Cirsium arvense

USDA-ARS?s Scientific Manuscript database

In this study, effective spread of aeciospores from an area source in a field was fit to an exponential decline model with a predicted maximum distance of spread of 30 m from the area source to observed uredinia on one leaf of one C. arvense shoot. However, the greatest number of shoots bearing leav...
Studies on low-loss coupling of non-node anti-resonant hollow-core fiber and tapered fiber

NASA Astrophysics Data System (ADS)

Zhang, Naiqian; Wang, Zefeng; Liu, Wenbo; Xi, Xiaoming

2017-10-01

Up to now, near almost optical fiber gas lasers employ/adopt the scheme of free-space coupling, which increases the difficulty to adjust the optical path, and has poor stability. All-fiber structure fiber-gas lasers are important development directions in the future. We established the numerical model of SMF-28 type tapered single-mode fiber and non-node hollow-core fiber. When the SMF-28 type single-mode fiber has a waist diameter of 40μm when the light source is LP01 fundamental mode with 1550nm wavelength, the mode field diameter is the largest. Meanwhile, we simulated that the equivalent mode field diameter of non-node anti-resonant hollow-core fiber is about 75μm at the same 1550nm wavelength light source. Then, we use different waist diameters of SMF-28 type tapered fibers injected to the non-node anti-resonant hollow-core fiber in simulation and experiments. In the scheme of the single-ended low-loss coupling, the simulation results indicate that the best waist diameter of tapered fiber is 40μm, and the calculated maximum coupling efficiency is 83.55%. Meanwhile, the experimental result of maximum coupling efficiency is 80.74% when the best waist diameter of tapered fiber is also 40μm. As for the double-ended low-loss coupling, the calculated maximum coupling efficiency is near 83.38%.
Rhododendron thickets alter N Cycling and soul extracellular enzyme activities in southern Appalachian hardwood forests

Treesearch

Nina Wurzburger; Ronald L. Hendrick

2007-01-01

Rhododendron maximum L., a spreading understory shrub, inhibits overstory. Regeneration and alters forest community structure in southern Appalachian hardwood forests. Using paired plots and reciprocal litter transplants in forests with and without R. maximum cover, we examined the influence of R. maximum on Leaf...
A Score to Identify Patients with Brain Metastases from Colorectal Cancer Who May Benefit from Whole-brain Radiotherapy in Addition to Stereotactic Radiosurgery/Radiotherapy.

PubMed

Rades, Dirk; Dziggel, Liesa; Blanck, Oliver; Gebauer, Niklas; Bartscht, Tobias; Schild, Steven E

2018-05-01

To design a tool to predict the probability of new cerebral lesions after stereotactic radiosurgery/radiotherapy for patients with 1-3 brain metastases from colorectal cancer. In 21 patients, nine factors were evaluated for freedom from new brain metastases, namely age, gender, Karnofsky performance score (KPS), tumor type, number, maximum total diameter of all lesions and sites of cerebral lesions, extra-cranial metastases, and time from cancer diagnosis to irradiation. Freedom from new lesions was positively associated with KPS of 90-100 (p=0.013); maximum total diameter ≤15 mm showed a trend for positive association (p=0.09). Points were assigned as: KPS 70-80=1 point, KPS 90-100=2 points, maximum diameter ≤15 mm=2 points and maximum diameter >15 mm=1 point. Six-month rates of freedom from new lesions were 29%, 45% and 100% for those with total scores of 2, 3 and 4 points, respectively, with corresponding 12-month rates of 0%, 45% and 100% (p=0.027). This study identified three risk groups regarding new brain metastases after stereotactic irradiation. Patients with 2 points could benefit from additional whole-brain radiotherapy. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.
Benefits of Two Turbine Rotor Diameters and Hub Heights in the Same Wind Farm

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

Dykes, Katherine L; Stanley, Andrew P. J.; Ning, Andrew

Significant turbine-wake interactions greatly reduce power output in a wind farm. If different turbine hub heights and rotor diameters are included in the same wind farm, the wake interference in the farm will be reduced, resulting in a lower cost of energy (COE) than a farm with identical turbines. In this paper, we present a method to model wind farm COE in farms with hub heights and rotor diameters that vary across the wind farm. We also demonstrate how to optimize these wind farms to minimize COE. The results show that COE can be greatly reduced in wind farms withmore » non-homogeneous turbines, especially when the turbines are spaced close together. For a unidirectional wind rose, including different turbine design in the wind farm has a similar decrease in COE to spreading the wind turbines farther apart. When the rotor diameter and hub height of the wind turbines in a farm are optimized uniformly, a COE decrease of 4% to 13% (depending on the grid spacing and wind shear exponent) is achieved compared to the baseline. When the rotor diameter and turbine heights are optimized non-uniformly, with two different diameters and heights throughout the farm, there is a COE decrease of 22% to 41% compared to the baseline. For a more spread wind rose with a dominant probability from the west, there is a COE decrease between 3% and 10% for uniformly optimized rotor diameter and height compared to the baseline. With two optimized rotor diameters and heights through the farm, a COE decrease of 3% to 19% is achieved. For a similar wind rose shifted such that the dominant wind direction is from the northwest, a COE decrease between 3% and 10% results from uniformly optimized wind turbines compared to the baseline. A COE decrease of 3% to 17% compared to the baseline occurs with two different turbines are optimized throughout the wind farm.« less
Rotating flexible drag mill

DOEpatents

Pepper, W.B.

1984-05-09

A rotating parachute for decelerating objects travelling through atmosphere at subsonic or supersonic deployment speeds includes a circular canopy having a plurality of circumferentially arranged flexible panels projecting radially from a solid central disk. A slot extends radially between adjacent panels to the outer periphery of the canopy. Upon deployment, the solid disk diverts air radially to rapidly inflate the panels into a position of maximum diameter. Air impinging on the panels adjacent the panel slots rotates the parachute during its descent. Centrifugal force flattens the canopy into a constant maximum diameter during terminal descent for maximum drag and deceleration.
Airflow and temperature distribution inside the maxillary sinus: a computational fluid dynamics simulation.

PubMed

Zang, Hongrui; Liu, Yingxi; Han, Demin; Zhang, Luo; Wang, Tong; Sun, Xiuzhen; Li, Lifeng

2012-06-01

The airflow velocity and flux in maxillary sinuses were much lower than those in the nasal cavity, and the temperature in maxillary sinuses was much higher than the temperature in the middle meatus. With the increase of maximum diameter of the ostium, the above indices changed little. The purpose of the paper was to investigate, first, the flow and temperature distribution inside normal maxillary sinus in inspiration, and second, flow and temperature alteration with the increase of maximum ostium diameter. Three-dimensional models with nasal cavities and bilateral maxillary sinuses were constructed for computational fluid dynamics analysis. Virtual surgeries were implemented for the maxillary ostium, the maximum diameters of which were 8, 10, 12, and 15 mm, respectively. The finite volume method was used for numerical simulation. The indices of velocity, pressure, vector, and temperature were processed and compared between models. The airflow velocity in maxillary sinuses (average velocity 0.062 m/s) was much lower than that in the middle meatus (average velocity 3.26 m/s). With the increase of ostium diameter, airflow characteristics distributed in the maxillary sinuses changed little. The normal temperature in the maxillary sinus remained almost constant at 34°C and changed little with the increase of ostium diameter.
Spread prediction model of continuous steel tube based on BP neural network

NASA Astrophysics Data System (ADS)

Zhai, Jian-wei; Yu, Hui; Zou, Hai-bei; Wang, San-zhong; Liu, Li-gang

2017-07-01

According to the geometric pass of roll and technological parameters of three-roller continuous mandrel rolling mill in a factory, a finite element model is established to simulate the continuous rolling process of seamless steel tube, and the reliability of finite element model is verified by comparing with the simulation results and actual results of rolling force, wall thickness and outer diameter of the tube. The effect of roller reduction, roller rotation speed and blooming temperature on the spread rule is studied. Based on BP(Back Propagation) neural network technology, a spread prediction model of continuous rolling tube is established for training wall thickness coefficient and spread coefficient of the continuous rolling tube, and the rapid and accurate prediction of continuous rolling tube size is realized.
Improved Fibroblast Functionalities by Microporous Pattern Fabricated by Microelectromechanical Systems

PubMed Central

Wei, Hongbo; Zhao, Lingzhou; Chen, Bangdao; Bai, Shizhu; Zhao, Yimin

2014-01-01

Fibroblasts, which play an important role in biological seal formation and maintenance, determine the long-term success of percutaneous implants. In this study, well-defined microporous structures with micropore diameters of 10–60 µm were fabricated by microelectromechanical systems and their influence on the fibroblast functionalities was observed. The results show that the microporous structures with micropore diameters of 10–60 µm did not influence the initial adherent fibroblast number; however, those with diameters of 40 and 50 µm improved the spread, actin stress fiber organization, proliferation and fibronectin secretion of the fibroblasts. The microporous structures with micropore diameters of 40–50 µm may be promising for application in the percutaneous part of an implant. PMID:25054322
Predicting liver metastasis of gastrointestinal tract cancer by diffusion-weighted imaging of apparent diffusion coefficient values

PubMed Central

Zheng, De-Xian; Meng, Shu-Chun; Liu, Qing-Jun; Li, Chuan-Ting; Shang, Xi-Dan; Zhu, Yu-Seng; Bai, Tian-Jun; Xu, Shi-Ming

2016-01-01

AIM: To determine if efficacy of chemotherapy on liver metastasis of gastrointestinal tract cancer can be predicted by apparent diffusion coefficient (ADC) values of diffusion-weighted imaging (DWI). METHODS: In total, 86 patients with liver metastasis of gastrointestinal tract cancer (156 metastatic lesions) diagnosed in our hospital were included in this study. The maximum diameters of these tumors were compared with each other before treatment, 2 wk after treatment, and 12 wk after treatment. Selected patients were classified as the effective group and the ineffective group, depending on the maximum diameter of the tumor after 12 wk of treatment; and the ADC values at different treatment times between the two groups were compared. Spearman rank correlation was used to analyze the relationship between ADC value and tumor diameter. Receiver operating characteristic curve (ROC curve) was used to analyze the ADC values before treatment to predict the patient’s sensitivity and specificity degree of efficacy to the chemotherapy. RESULTS: There was no difference in age between the two groups and in maximum tumor diameter before treatment and 2 wk after treatment. However, after 12 wk of treatment, maximum tumor diameter in the effective group was significantly lower than that in the ineffective group (P < 0.05). Before treatment, ADC values in the ineffective group were significantly higher than those in the effective group (P < 0.05). There was no difference in ADC values between the effective and ineffective groups after 2 and 12 wk of treatment. However, ADC values were significantly higher after 2 and 12 wk of treatment compared to before treatment in the effective group (P < 0.05). Spearman rank correlation analysis showed that ADC value before treatment and the reduced percentage of the maximum tumor diameter after 12 wk of treatment were negatively correlated, while the increase in the percentage of the ADC value 12 wk after treatment and the decrease in the percentage of the maximum tumor diameter were significantly positively correlated. The results of the ROC curve showed that ADC value with a chemotherapy ineffective threshold value of 1.14 × 10-3 mm2/s before treatment had a sensitivity and specificity of 94.3% and 76.7%, respectively. CONCLUSION: DWI ADC values can be used to predict the response of patients with liver metastasis of gastrointestinal tract cancer to chemotherapy with high sensitivity and relatively high specificity. PMID:26973399
Fc-receptor induced cell spreading during frustrated phagocytosis in J774A.1 macrophages

NASA Astrophysics Data System (ADS)

Kovari, Daniel; Curtis, Jennifer; Wei, Wenbin

2014-03-01

Phagocytosis is the process where by cells engulf foreign particles. It is the primary mechanism through which macrophages and neutrophils (white blood cells) eliminate pathogens and debris from the body. The behavior is the result of a cascade of chemical and mechanical cues, which result in the actin-driven expansion of the cell's membrane around its target. For macrophages undergoing Fc-mediated phagocytosis, we show that above a minimum threshold the spreading rate and maximum cell-target contact area are independent of the target's opsonin density. Qualitatively, macrophage phagocytic spreading is similar to the spreading of other cell types (e.g. fibroblasts, lymphocytes, and Dict.d.). Early spreading is most likely the result of ``passive'' alignment of the cell to the target surface. This is followed by an active expansion period driven by actin. Finally upon reaching a maximum contact area, typically 2-3 times the size of ``non-activated'' cells, macrophages often undergo a period of rapid contraction not reported in other cell types. We hypothesize that this, as yet unexplained, transition may be specific to the chemical and mechanical machinery associated with phagocytosis. This work was funded by NSF grant PHYS 0848797 and NSF grant DMR 0820382.
Size effects on miniature Stirling cycle cryocoolers

NASA Astrophysics Data System (ADS)

Yang, Xiaoqin; Chung, J. N.

2005-08-01

Size effects on the performance of Stirling cycle cryocoolers were investigated by examining each individual loss associated with the regenerator and combining these effects. For the fixed cycle parameters and given regenerator length scale, it was found that only for a specific range of the hydrodynamic diameter the system can produce net refrigeration and there is an optimum hydraulic diameter at which the maximum net refrigeration is achieved. When the hydraulic diameter is less than the optimum value, the regenerator performance is controlled by the pressure drop loss; when the hydraulic diameter is greater than the optimum value, the system performance is controlled by the thermal losses. It was also found that there exists an optimum ratio between the hydraulic diameter and the length of the regenerator that offers the maximum net refrigeration. As the regenerator length is decreased, the optimum hydraulic diameter-to-length ratio increases; and the system performance is increased that is controlled by the pressure drop loss and heat conduction loss. Choosing appropriate regenerator characteristic sizes in small-scale systems are more critical than in large-scale ones.
Pre-operative predictive factors for gallbladder cholesterol polyps using conventional diagnostic imaging

PubMed Central

Choi, Ji-Hoon; Yun, Jung-Won; Kim, Yong-Sung; Lee, Eun-A; Hwang, Sang-Tae; Cho, Yong-Kyun; Kim, Hong-Joo; Park, Jung-Ho; Park, Dong-Il; Sohn, Chong-Il; Jeon, Woo-Kyu; Kim, Byung-Ik; Kim, Hyoung-Ook; Shin, Jun-Ho

2008-01-01

AIM: To determine the clinical data that might be useful for differentiating benign from malignant gallbladder (GB) polyps by comparing radiological methods, including abdominal ultrasonography (US) and computed tomography (CT) scanning, with postoperative pathology findings. METHODS: Fifty-nine patients underwent laparoscopic cholecystectomy for a GB polyp of around 10 mm. They were divided into two groups, one with cholesterol polyps and the other with non-cholesterol polyps. Clinical features such as gender, age, symptoms, size and number of polyps, the presence of a GB stone, the radiologically measured maximum diameter of the polyp by US and CT scanning, and the measurements of diameter from postoperative pathology were recorded for comparative analysis. RESULTS: Fifteen of the 41 cases with cholesterol polyps (36.6%) were detected with US but not CT scanning, whereas all 18 non-cholesterol polyps were observed using both methods. In the cholesterol polyp group, the maximum measured diameter of the polyp was smaller by CT scan than by US. Consequently, the discrepancy between those two scanning measurements was greater than for the non-cholesterol polyp group. CONCLUSION: The clinical signs indicative of a cholesterol polyp include: (1) a polyp observed by US but not observable by CT scanning, (2) a smaller diameter on the CT scan compared to US, and (3) a discrepancy in its maximum diameter between US and CT measurements. In addition, US and the CT scan had low accuracy in predicting the polyp diameter compared to that determined by postoperative pathology. PMID:19058309
Pre-operative predictive factors for gallbladder cholesterol polyps using conventional diagnostic imaging.

PubMed

Choi, Ji-Hoon; Yun, Jung-Won; Kim, Yong-Sung; Lee, Eun-A; Hwang, Sang-Tae; Cho, Yong-Kyun; Kim, Hong-Joo; Park, Jung-Ho; Park, Dong-Il; Sohn, Chong-Il; Jeon, Woo-Kyu; Kim, Byung-Ik; Kim, Hyoung-Ook; Shin, Jun-Ho

2008-11-28

To determine the clinical data that might be useful for differentiating benign from malignant gallbladder (GB) polyps by comparing radiological methods, including abdominal ultrasonography (US) and computed tomography (CT) scanning, with postoperative pathology findings. Fifty-nine patients underwent laparoscopic cholecystectomy for a GB polyp of around 10 mm. They were divided into two groups, one with cholesterol polyps and the other with non-cholesterol polyps. Clinical features such as gender, age, symptoms, size and number of polyps, the presence of a GB stone, the radiologically measured maximum diameter of the polyp by US and CT scanning, and the measurements of diameter from postoperative pathology were recorded for comparative analysis. Fifteen of the 41 cases with cholesterol polyps (36.6%) were detected with US but not CT scanning, whereas all 18 non-cholesterol polyps were observed using both methods. In the cholesterol polyp group, the maximum measured diameter of the polyp was smaller by CT scan than by US. Consequently, the discrepancy between those two scanning measurements was greater than for the non-cholesterol polyp group. The clinical signs indicative of a cholesterol polyp include: (1) a polyp observed by US but not observable by CT scanning, (2) a smaller diameter on the CT scan compared to US, and (3) a discrepancy in its maximum diameter between US and CT measurements. In addition, US and the CT scan had low accuracy in predicting the polyp diameter compared to that determined by postoperative pathology.
Optimising the measurement of bruises in children across conventional and cross polarized images using segmentation analysis techniques in Image J, Photoshop and circle diameter measurements.

PubMed

Harris, C; Alcock, A; Trefan, L; Nuttall, D; Evans, S T; Maguire, S; Kemp, A M

2018-02-01

Bruising is a common abusive injury in children, and it is standard practice to image and measure them, yet there is no current standard for measuring bruise size consistently. We aim to identify the optimal method of measuring photographic images of bruises, including computerised measurement techniques. 24 children aged <11 years (mean age of 6.9, range 2.5-10 years) with a bruise were recruited from the community. Demographics and bruise details were recorded. Each bruise was measured in vivo using a paper measuring tape. Standardised conventional and cross polarized digital images were obtained. The diameter of bruise images were measured by three computer aided measurement techniques: Image J (segmentation with Simple Interactive Object Extraction (maximum Feret diameter), 'Circular Selection Tool' (Circle diameter), & the Photoshop 'ruler' software (Photoshop diameter)). Inter and intra-observer effects were determined by two individuals repeating 11 electronic measurements, and relevant Intraclass Correlation Coefficient's (ICC's) were used to establish reliability. Spearman's rank correlation was used to compare in vivo with computerised measurements; a comparison of measurement techniques across imaging modalities was conducted using Kolmogorov-Smirnov tests. Significance was set at p < 0.05 for all tests. Images were available for 38 bruises in vivo, with 48 bruises visible on cross polarized imaging and 46 on conventional imaging (some bruises interpreted as being single in vivo appeared to be multiple in digital images). Correlation coefficients were >0.5 for all techniques, with maximum Feret diameter and maximum Photoshop diameter on conventional images having the strongest correlation with in vivo measurements. There were significant differences between in vivo and computer-aided measurements, but none between different computer-aided measurement techniques. Overall, computer aided measurements appeared larger than in vivo. Inter- and intra-observer agreement was high for all maximum diameter measurements (ICC's > 0.7). Whilst there are minimal differences between measurements of images obtained, the most consistent results were obtained when conventional images, segmented by Image J Software, were measured with a Feret diameter. This is therefore proposed as a standard for future research, and forensic practice, with the proviso that all computer aided measurements appear larger than in vivo. Copyright © 2018 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Spreading of a Lidocaine Formulation on Microneedle-Treated Skin.

PubMed

Nayak, Atul; Das, Diganta B; Chao, Tzu C; Starov, Victor M

2015-12-01

The spreadability of a liquid drug formulation on skin is an indication of it either remaining stationary or distributing (spreading) as a droplet. Factors determining droplet spreadability of the formulation are spreading area, diameter of the droplet base, viscosity of the liquid, contact angle, volume of droplet on skin and any others. The creation of microcavities from the application of microneedle (MN) has the potential to control droplet spreading, and hence, target specific areas of skin for drug delivery. However, there is little work that demonstrates spreading of liquid drug formulation on MN-treated skin. Below, spreading of a lidocaine hydrogel formulation and lidocaine solution (reference liquid) on porcine skin is investigated over MN-treated skin. Controlled spreadability was achieved with the lidocaine hydrogel on MN-treated skin as compared with lidocaine solution. It was observed that the droplet spreading parameters such as spreading radius, droplet height and dynamic contact angle were slightly lower for the lidocaine hydrogel than the lidocaine solution on skin. Also, the lidocaine hydrogel on MN-treated skin resulted in slower dynamic reduction of droplet height, contact angle and reduced time taken in attaining static advancing droplets because of the MN microcavities. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.
Experimental Pressure Distributions on Axisymmetric Cowls at Mach Numbers From 0.60 to 0.92

NASA Technical Reports Server (NTRS)

Re, Richard J.

2006-01-01

Pressure distributions on four nacelle cowl models of the same length and highlight area but different geometries external to the highlight are compared. The diameter ratio (ratio of highlight diameter to maximum diameter) of the four cowls was 0.854 and the length ratio (ratio of cowl length to maximum diameter) was 0.439. The cowls had the same internal geometry from the highlight to the throat with a contraction ratio (ratio of highlight area to throat area) of 1.250. Data for two other cowls which had a diameter ratio of 0.880, a length ratio of 0.400 and a contraction ratio 1.250 are also included. All the cowls had rows of static pressure orifices on the top and bottom surfaces. Mass-flow ratio was varied between 0.27 and 0.93. Some data were obtained between angles of attack from -2.1deg and 4.1deg. The test was conducted in the Langley 16-Foot Transonic Tunnel.
Fundamental studies of bloodstain formation and characteristics.

PubMed

Adam, Craig D

2012-06-10

A detailed understanding of blood droplet impact dynamics and stain formation is an essential prerequisite to the interpretation of both individual bloodstains and spatter patterns. The current literature on theoretical models for the spreading and splashing of liquid drops on surfaces relevant to the forensic context of bloodstain formation has been reviewed. These models have been evaluated for a paper substrate using experimental data obtained as function of droplet size, impact velocity and angle. It is shown that for perpendicular impact there are fairly simple mathematical models for the spreading diameter and the number of scallops or spines formed around the stain though these have quite limited ranges of validity in their basic form. In particular, predictions for the diameter are best for small droplets impacting at high velocity and the number of spines saturates for higher impact velocities. In the case of spreading, a modification to the energy conservation model is found to provide excellent agreement with experimental stain diameters across a wide range of impact velocities. For non-perpendicular impact, the width of stains is found to depend principally on the normal component of impact velocity and may be predicted by an appropriate modification to the expression for the perpendicular case. Limitations in the calculation of impact angle from the stain aspect ratio are identified and a theoretical basis for the prediction of spines around an elliptical stain is proposed. Some key issues for future research are identified which include a systematic, quantitative study of the effect of surface properties on bloodstain formation. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Ion energy spread and current measurements of the rf-driven multicusp ion source

NASA Astrophysics Data System (ADS)

Lee, Y.; Gough, R. A.; Kunkel, W. B.; Leung, K. N.; Perkins, L. T.; Pickard, D. S.; Sun, L.; Vujic, J.; Williams, M. D.; Wutte, D.

1997-03-01

Axial energy spread and useful beam current of positive ion beams have been carried out using a radio frequency (rf)-driven multicusp ion source. Operating the source with a 13.56 MHz induction discharge, the axial energy spread is found to be approximately 3.2 eV. The extractable beam current of the rf-driven source is found to be comparable to that of filament-discharge sources. With a 0.6 mm diameter extraction aperture, a positive hydrogen ion beam current density of 80 mA/cm2 can be obtained at a rf input power of 2.5 kW. The expected source lifetime is much longer than that of filament discharges.
Electroluminescence of ordered ZnO nanorod array/p-GaN light-emitting diodes with graphene current spreading layer

PubMed Central

2014-01-01

Ordered ZnO nanorod array/p-GaN heterojunction light-emitting diodes (LEDs) have been fabricated by introducing graphene as the current spreading layer, which exhibit improved electroluminescence performance by comparison to the LED using a conventional structure (indium-tin-oxide as the current spreading layer). In addition, by adjusting the diameter of ZnO nanorod array in use, the light emission of the ZnO nanorod array/p-GaN heterojunction LEDs was enhanced further. This work has great potential applications in solid-state lighting, high performance optoelectronic devices, and so on. PACS 78.60.Fi; 85.60.Jb; 78.67.Lt; 81.10.Dn PMID:25489284
Electroluminescence of ordered ZnO nanorod array/p-GaN light-emitting diodes with graphene current spreading layer.

PubMed

Dong, Jing-Jing; Hao, Hui-Ying; Xing, Jie; Fan, Zhen-Jun; Zhang, Zi-Li

2014-01-01

Ordered ZnO nanorod array/p-GaN heterojunction light-emitting diodes (LEDs) have been fabricated by introducing graphene as the current spreading layer, which exhibit improved electroluminescence performance by comparison to the LED using a conventional structure (indium-tin-oxide as the current spreading layer). In addition, by adjusting the diameter of ZnO nanorod array in use, the light emission of the ZnO nanorod array/p-GaN heterojunction LEDs was enhanced further. This work has great potential applications in solid-state lighting, high performance optoelectronic devices, and so on. 78.60.Fi; 85.60.Jb; 78.67.Lt; 81.10.Dn.
Options for small-diameter hardwood utilization: past and present

Treesearch

Matthew S. Bumgardner; Bruce G. Hansen; Albert T. Schuler; Philip A. Araman

2000-01-01

Effective and maximum value use of small-diameter hardwood timber has long been of interest to forest managers and researchers. In addition to being a significant component of the standing forest base, small-diameter hardwoods often are available after thinning or other tending operations. Although the use of this material is important to achieving healthy and...
Options for Small-Diameter Hardwood Utilization: Past and Present

Treesearch

Matthew S. Bumgardner; Bruce G. Hansen; Albert T. Schuler; Philip A. Araman; Philip A. Araman

2001-01-01

Effective and maximum value use of small-diameter hardwood timber has long been of interest to forest managers and researchers. In addition to being a significant component of the standing forest base, small-diameter hardwoods often are available after thinning or other tending operations. Although the use of this material is important to achieving healthy and...
Rapid surface colony counts determination with three new miniaturised techniques.

PubMed

Malik, K A

1977-01-01

Three different miniaturised methods for the rapid surface viable counting are described. The methods were tried in parallel to seven different existing methods (Table 1) for viable counts and were found to be easier, quicker and insome cases more accurate. The techniques require about 10% of the material and time needed for conventional spread-plates method and the results were in no way inferior to that (Table 1 and 2). Mini agar discs were cut aseptically with an especially designed stainless steel agar disc cutter (25 mm internal and 28 mm external diameter, Fig. 1b) or with a test tube of similar diameter. The area of the resulted mini-agar-disc of 25 mm diameter was kept such (about 1/10th of the normal plate) that the ratio of the colony-bearing area to the inoculm remained the same as on big plates in spread-plate-method (Table 2). In normal Petri dishes (about 90 mm diameter) up to seven mini agar discs were possible to cut. Each small agar disc was seperated from the other mini-disc by a distance of at least 6 mm (Fig. 1a). The empty place around the disc was still enlarged during over drying of the plates and during incubation. This created complete isolation from the neighbouring disc. For micro-determination of surface viable counts 10 micronl from each dilution was delivered on a well-dired mini-disc with a piston micropipette. The inoculm was immediately spread on the whole mini-disc with a specially designed flame sterilizable platinum-Mini-spreader (Fig. 2a). No spinning of the plate was needed. Alternatively the dropping pipette and spreader was replaced by a calibrated platinum wire Loop-spreader (Fig. 2b). A loop of 3 mm internal diameter made from a platinum-iridium wire of 0.75 mm thickness proved most useful and carried a drop of 10 micronl. Differences especially in surface tension of various diluting fluids did not influence to drop of this size and no recalibration was needed for water and nutrient broth. The loop was further shaped to Loop-spreader form. From each bacterial suspension 10 micronl were carried and spread on each mini-disc. The method is useful for pathogenic organisms as the loop can readily be flame sterilized. For routine purposes where only approximate numbers of bacteria need to be known a still rapid semiquantitative method was deviced making use of a calibrated stainless steel Stamping-disc (Fig. 2c). A disc of 25mm diameter and 1 mm thickness delivered approximateyl 10 microlitres of supensions and was found to be most useful to stamp seven dilutions on a single plate. In collections and bacteriology laboratories where by conventional methods large number of plates are to be plated and counted the presented techniques could prove most convenient, rapid and economical.
Analytical correlation of centrifugal compressor design geometry for maximum efficiency with specific speed

NASA Technical Reports Server (NTRS)

Galvas, M. R.

1972-01-01

Centrifugal compressor performance was examined analytically to determine optimum geometry for various applications as characterized by specific speed. Seven specific losses were calculated for various combinations of inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, blade exit backsweep, and inlet-tip absolute tangential velocity for solid body prewhirl. The losses considered were inlet guide vane loss, blade loading loss, skin friction loss, recirculation loss, disk friction loss, vaneless diffuser loss, and vaned diffuser loss. Maximum total efficiencies ranged from 0.497 to 0.868 for a specific speed range of 0.257 to 1.346. Curves of rotor exit absolute flow angle, inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, head coefficient and blade exit backsweep are presented over a range of specific speeds for various inducer tip speeds to permit rapid selection of optimum compressor size and shape for a variety of applications.
Energetic analysis of drop's maximum spreading on solid surface with low impact speed

NASA Astrophysics Data System (ADS)

Huang, Hai-Meng; Chen, Xiao-Peng

2018-02-01

Drops impacting on a flat solid surface will spread until it reaches maximum contact with the substrate underneath. After that, it recoils. In the present work, the variations of energy components during the spreading are studied carefully, including kinetic, capillary, and dissipated energies. Our experimental and numerical results show that, when the impact speed is low, the fast slipping of the contact line (in inertia-capillary regime) and corresponding "interface relaxation" lead to extra dissipation. An auxiliary dissipation is therefore introduced into the traditional theoretical model. The energy components predicted by the improved model agree with the experimental and numerical results very well. As the impact speed increases (the Weber number, W e =ρ D0V02/γ , becomes larger than 40 in the present work), the dissipation induced by the initial velocity plays more important roles. The analyses also indicate that on the hydrophobic surfaces the auxiliary dissipation is lower than that on hydrophilic ones. In the later circumstances, the contact angle is larger and the spreading is weaker.
Spreading of Emulsions on Glass Substrates

NASA Astrophysics Data System (ADS)

Mohammad Karim, Alireza; Kavehpour, Pirouz

2012-11-01

The wettability of emulsions is an important factor with explicit influence in an extensive variety of industrial applications ranging from the petroleum to food industries. Surprisingly, there is no comprehensive study of emulsion spreading to date; this is due to the complexity of the structure of the emulsions and non-homogeneity of the dispersed phase bubbles in size as well as distribution through the emulsion. The spreading of water/silicone oil emulsions on glass substrates was investigated. The emulsions were prepared with varying volume fractions of water dispersed in silicone oil, with addition of small amounts of surfactant to stabilize the emulsion structure. The time dependent variation of dynamic contact angle, base diameter, and the spreading rate of the droplets of an emulsion are different from a pure substance. The effect of water/silicone oil weight percentage as well as the droplet size and dispersed phase bubble size were also investigated. The weight percentage of water/silicone oil emulsion and droplet size did not have significant influence on the spreading dynamics; however the dispersed phase drop size affected the spreading dynamics substantially.
Comparison of Direct Sequence Spread Spectrum Rake Receiver with a Maximum Ratio Combining Multicarrier Spread Spectrum Receiver

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

Daryl Leon Wasden; Hussein Moradi; Behrouz Farhang-Broujeny

2014-06-01

This paper presents a theoretical analysis of the performance of a filter bank-based multicarrier spread spectrum (FB-MC-SS) system. We consider an FB-MC-SS setup where each data symbol is spread across multiple subcarriers, but there is no spreading in time. The results are then compared with those of the well-known direct sequence spread spectrum (DS-SS) system with a rake receiver for its best performance. We compare the two systems when the channel noise is white. We prove that as the processing gains of the two systems tend to infinity both approach the same performance. However, numerical simulations show that, in practice,more » where processing gain is limited, FB-MC-SS outperforms DS-SS.« less
Estimation of viscous dissipation in nanodroplet impact and spreading

NASA Astrophysics Data System (ADS)

Li, Xin-Hao; Zhang, Xiang-Xiong; Chen, Min

2015-05-01

The developments in nanocoating and nanospray technology have resulted in the increasing importance of the impact of micro-/nanoscale liquid droplets on solid surface. In this paper, the impact of a nanodroplet on a flat solid surface is examined using molecular dynamics simulations. The impact velocity ranges from 58 m/s to 1044 m/s, in accordance with the Weber number ranging from 0.62 to 200.02 and the Reynolds number ranging from 0.89 to 16.14. The obtained maximum spreading factors are compared with previous models in the literature. The predicted results from the previous models largely deviate from our simulation results, with mean relative errors up to 58.12%. The estimated viscous dissipation is refined to present a modified theoretical model, which reduces the mean relative error to 15.12% in predicting the maximum spreading factor for cases of nanodroplet impact.
A 12 coil superconducting bumpy torus magnet facility for plasma research

NASA Technical Reports Server (NTRS)

Roth, J. R.; Holmes, A. D.; Keller, T. A.; Krawczonek, W. M.

1972-01-01

A summary is presented of the performance of the two-coil superconducting pilot rig which preceded the NASA Lewis bumpy torus. This pilot rig was operated for 550 experimental runs over a period of 7 years. The NASA Lewis bumpy torus facility consists of 12 superconducting coils, each with a 19 cm in diameter and capable of producing magnetic field strengths of 3.0 teslas on their axes. The magnets are equally spaced around a major circumference 1.52 m in diameter, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.59 m in diameter. The design value of maximum magnetic field on the magnetic axis (3.0 teslas) was reached and exceeded. A maximum magnetic field of 3.23 teslas was held for a period of 60 minutes, and the coils did not go to normal. When the coils were charged to a maximum magnetic field of 3.35 teslas, the coil system was driven normal without damage to the facility.
Biomechanical optimization of implant diameter and length for immediate loading: a nonlinear finite element analysis.

PubMed

Kong, Liang; Gu, Zexu; Li, Tao; Wu, Junjie; Hu, Kaijin; Liu, Yanpu; Zhou, Hongzhi; Liu, Baolin

2009-01-01

A nonlinear finite element method was applied to examine the effects of implant diameter and length on the maximum von Mises stresses in the jaw, and to evaluate the maximum displacement of the implant-abutment complex in immediate-loading models. The implant diameter (D) ranged from 3.0 to 5.0 mm and implant length (L) ranged from 6.0 to 16.0 mm. The results showed that the maximum von Mises stress in cortical bone was decreased by 65.8% under a buccolingual load with an increase in D. In cancellous bone, it was decreased by 71.5% under an axial load with an increase in L. The maximum displacement in the implant-abutment complex decreased by 64.8% under a buccolingual load with an increase in D. The implant was found to be more sensitive to L than to D under axial loads, while D played a more important role in enhancing its stability under buccolingual loads. When D exceeded 4.0 mm and L exceeded 11.0 mm, both minimum stress and displacement were obtained. Therefore, these dimensions were the optimal biomechanical selections for immediate-loading implants in type B/2 bone.
SOME PRACTICAL MODIFICATIONS ON HIGH FREQUENCY ION SOURCES (in Hungarian)

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

Nagy, J.; Gombos, P.

1962-05-01

A radiofrequency ion source was constructed for the 800-kv cascade type accelerator and 300-kv neutron generator built in the Institute. Besides the usual transversal magnetic field of 50 gauss, an axial magnetic field of 250 gauss intensity was also applied in the immediate neighborhood of the probe. As a result of this, the service life of the discharge tube was increased by several hundred hours but in comparison with the measurements of other authors the percentage of protons underwent no change. The quartz calyx which was built to surround the probe, contributed considerably to an increase of the service life.more » Measurements concerning the selection of the pre-focusing lens are summarized. With a probe of 1.3-mm canal diameter, a maximum 1.9 ma pre-focused ion current was obtained in H/sub 2/ with a gas consumption of 8 to 10 cm/sup 3//hr, (With a probe of 1.7-mm canal diameter, at a gas consumption of 25 cm/sup 3//hr, 2.7 ma current was obtained.) The total consumption of the ion source amounted to 800 w with prefocusing. The energy-spread of the ion beam was found to be 200 ev. Having built it into the cascade type accelerator 1 ma current was measured on the target at an accelerating voltage of 500 kv, where this amount included the secondary electrons as well. (auth)« less
Proton Therapy At Siteman Cancer Center: The State Of The Art

NASA Astrophysics Data System (ADS)

Bloch, Charles

2011-06-01

Barnes-Jewish Hospital is on the verge of offering proton radiation therapy to its patients. Those treatments will be delivered from the first Monarch 250, a state-of-the-art cyclotron produced by Still River Systems, Inc., Littleton, MA. The accelerator is the world's first superconducting synchrocyclotron, with a field-strength of 10 tesla, providing the smallest accelerator for high-energy protons currently available. On May 14, 2010 it was announced that the first production unit had successfully extracted 250 MeV protons. That unit is scheduled for delivery to the Siteman Cancer Center, an NCI-designated Comprehensive Cancer Center at Washington University School of Medicine. At a weight of 20 tons and with a diameter of less than 2 meters the compact cyclotron will be mounted on a gantry, another first for proton therapy systems. The single-energy system includes 3 contoured scatterers and 14 different range modulators to provide 24 distinct beam delivery configurations. This allows proton fields up to 25 cm in diameter, with a maximum range from 5.5 to 32 cm and spread-out-Bragg-peak extent up to 20 cm. Monte Carlo simulations have been run using MCNPX to simulate the clinical beam properties. Those calculations have been used to commission a commercial treatment planning system prior to final clinical measurements. MCNPX was also used to calculate the neutron background generated by protons in the scattering system and patient. Additional details of the facility and current status will be presented.
A spreading drop model for plumes on Venus

NASA Astrophysics Data System (ADS)

Koch, D. M.

1994-01-01

Many of the large-scale, plume-related features on Venus can be modeled by a buoyant viscous drop, or plume head, as it rises and spreads laterally below a free fluid surface. The drop has arbitrary density and viscosity contrast and begins as a sphere below the surface of a fluid half space. The boundary integral method is used to solve for the motion of the plume head and for the topography, geoid, and stress at the fluid surface. As the plume approaches the surface, stresses in the fluid above it cause it to spread and become thin below the surface. During the spreading, the surface swell above evolves through various stages whose morphologies resemble several different plume-related features observed on Venus. When the plume head first approaches the surface, a high broad topographic dome develops, with a large geoid, and radial extensional deformation patterns. At later stages, the topography subsides and becomes plateau-like, the geoid to topography ratio (GTR) decreases, and the dominant stress pattern consists of a band of concentric extension surrounded by a band of concentric compression. We find that a low-viscosity model plume head (viscosity that is 0.1 times the mantle viscosity) produces maximum topography that is 20% lower, and swell features which evolve faster, than for an isoviscous plume. We compare model results with both the large-scale highland swells, and smaller-scale features such as coronae and novae. The dome-shaped highlands with large GTRs such as Beta, Atla, and Western Eistla Regiones may be the result of early stage plume motion, while the flatter highlands such as Ovda and Thetis Regiones which have lower GTRs may be later stage features. Comparison of model results with GTR data indicates that the highlands result from plume heads with initial diameters of about 1000 km. On a smaller scale, an evolutionary sequence may begin with novae (domes having radial extensional deformation), followed by features with radial and concentric deformation (such as arachnoids), and end with coronae (with mostly concentric deformation). The model predicts that the highlands evolve on a timescale of order 10 Ma, and the smaller-scale features evolve in a 100 Ma timescale.
Mechanisms of microgravity flame spread over a thin solid fuel - Oxygen and opposed flow effects

NASA Technical Reports Server (NTRS)

Olson, S. L.

1991-01-01

Microgravity tests varying oxygen concentration and forced flow velocity have examined the importance of transport processes on flame spread over very thin solid fuels. Flame spread rates, solid phase temperature profiles and flame appearance for these tests are measured. A flame spread map is presented which indicates three distinct regions where different mechanisms control the flame spread process. In the near-quenching region (very low characteristic relative velocities) a new controlling mechanism for flame spread - oxidizer transport-limited chemical reaction - is proposed. In the near-limit, blowoff region, high opposed flow velocities impose residence time limitations on the flame spread process. A critical characteristic relative velocity line between the two near-limit regions defines conditions which result in maximum flammability both in terms of a peak flame spread rate and minimum oxygen concentration for steady burning. In the third region, away from both near-limit regions, the flame spread behavior, which can accurately be described by a thermal theory, is controlled by gas-phase conduction.

Effect Of Low External Flow On Flame Spreading Over ETFE Insulated Wire Under Microgravity

NASA Technical Reports Server (NTRS)

Nishizawa, Katsuhiro; Fujita, Osamu; Ito, Kenichi; Kikuchi, Masao; Olson, Sandra L.; Kashiwagi, Takashi

2003-01-01

Fire safety is one of the most important issues for manned space missions. A likely cause of fires in spacecraft is wire insulation combustion in electrical system. Regarding the wire insulation combustion it important to know the effect of low external flow on the combustion because of the presence of ventilation flow in spacecraft. Although, there are many researches on flame spreading over solid material at low external flows under microgravity, research dealing with wire insulation is very limited. An example of wire insulation combustion in microgravity is the Space Shuttle experiments carried out by Greenberg et al. However, the number of experiments was very limited. Therefore, the effect of low flow velocity is still not clear. The authors have reported results on flame spreading over ETFE (ethylene - tetrafluoroetylene) insulated wire in a quiescent atmosphere in microgravity by 10 seconds drop tower. The authors also performed experiments of polyethylene insulated nichrom wire combustion in low flow velocity under microgravity. The results suggested that flame spread rate had maximum value in low flow velocity condition. Another interesting issue is the effect of dilution gas, especially CO2, which is used for fire extinguisher in ISS. There are some researches working on dilution gas effect on flame spreading over solid material in quiescent atmosphere in microgravity. However the research with low external flow is limited and, of course, the research discussing a relation of the appearance of maximum wire flammability in low flow velocity region with different dilution gas cannot be found yet. The present paper, therefore, investigates the effect of opposed flow with different dilution gas on flame spreading over ETFE insulated wire and change in the presence of the maximum flammability depending on the dilution gas type is discussed within the limit of microgravity time given by ground-based facility.
Dead wood relative to slope severity in mesic loess bluff hardwood forests

USGS Publications Warehouse

Twedt, Daniel J.

2012-01-01

To aid in identification of land within Vicksburg National Military Park that was subjected to forest restoration during the 1930s, I evaluated the hypothesized relationships between maximum live tree diameter or dead wood (standing and down) and severity of slope. Disproportionate mortality among early-successional, pioneer tree species suggested maturation of pioneer upland hardwood forests. As such, input and decomposition of dead wood have likely approached equilibrium. Thus, I did not detect a useful predictive relationship between dead wood (standing or down) or maximum diameter of live trees and severity of slope. Lack of relationships between slope and large diameter trees or volume of dead wood resulted in an inability to evaluate former land use based on these parameters.
Hair root diameter measurement as an indicator of protein deficiency in nonhospitalized alcoholics.

PubMed

Bregar, R R; Gordon, M; Whitney, E N

1978-02-01

Protein status of alcoholics admitted to a detoxification center was investigated with a view to adapting a hair root test for use in screening for protein deficiency. Hair root volume and hair root diameter had previously been shown to correlate well with hair root protein and to be sensitive indicators of protein deficiency. Hair root volumes in this study correlated well with mean maximum hair root diameters (n = 35, r = 0.9), which were simpler to measure, so diameter measurements were used. Mean maximum hair root diameters (range 0.02 to 0.19 mm) correlated with plasma RNase concentrations (range 6000 to 14,000 units/ml; n = 17, r = -0.7). Mean hair diameters of 84 alcoholics averaged 0.0864 +/- 0.0366 mm; those of 25 nonalcoholics were significantly greater: 0.100 +/- 0.0254 mm (P less than 0.05). Frequency of occurrence of hair root diameters of 0.06 mm or less was significantly higher in 71 alcoholics (29.5%) than in 23 nonalcoholics (8.6%) matched by age. Mean hair root diameters of 0.06 mm or less therefore can be used to signify protein deficiency where more expensive or technically demanding tests are not feasible. Protein deficiency occurs extensively in non hospitalized alcoholics. This method enables staff to single out those clients most likely to be in need of nutritional counseling and therapy.
Drop impact and wettability: From hydrophilic to superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Antonini, Carlo; Amirfazli, Alidad; Marengo, Marco

2012-10-01

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

PubMed

Severns, Paul M; Liston, Aaron; Wilson, Mark V

2011-01-01

Small population size, genetic diversity, and spatial patterns of vegetative spread are important aspects to consider when managing populations of rare clonal plant species. We used 5 variable nuclear simple sequence repeat nDNA loci to determine the extent of genet rhizome spread, examine the possibility of very small population sizes, and project how Bombus spp. (bumblebee) foraging may impact selfing (through geitonogamy) for a threatened lupine (Lupinus oreganus Heller) that sprawls through nonadventitious rhizomes. Genotyping identified 1 genet (27 × 13 m) that dominated about 30% of a study site, whereas 15 genets spread a maximum average distance of about 5.5 m (range 1.6 -27.1 m) and appeared to be well integrated with intervening genets. We found unexpectedly high genotype diversity, no evidence of a recent genetic bottleneck, and 5 of 6 patches had mean fixation index values that were near Hardy-Weinberg Equilibrium expectations. If the median maximum Bombus foraging distance observed in lupine patches (1.2 m) occurred within genotyped populations, a typical foraging flight would have >80% chance of occurring between different genets. Our study demonstrates that inferences associated with clonality, small population size, and inbreeding depression should be directly evaluated for rare vegetatively spreading plants.
49 CFR 173.417 - Authorized fissile materials packages.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for export and import shipments. (2) A residual “heel” of enriched solid uranium hexafluoride may be... “Heel” in a Specification 7A Cylinder) Maximum cylinder diameter Centimeters Inches Cylinder volume Liters Cubic feet Maximum Uranium 235-enrichment (weight)percent Maximum “Heel” weight per cylinder UF6...
49 CFR 173.417 - Authorized fissile materials packages.

Code of Federal Regulations, 2011 CFR

2011-10-01

... for export and import shipments. (2) A residual “heel” of enriched solid uranium hexafluoride may be... “Heel” in a Specification 7A Cylinder) Maximum cylinder diameter Centimeters Inches Cylinder volume Liters Cubic feet Maximum Uranium 235-enrichment (weight)percent Maximum “Heel” weight per cylinder UF6...
The longest wheal diameter is the optimal measurement for the evaluation of skin prick tests.

PubMed

Konstantinou, George N; Bousquet, Philippe-Jean; Zuberbier, Torsten; Papadopoulos, Nikolaos G

2010-01-01

Mean diameter or longest diameter are the 2 most frequently used parameters for wheal response assessment after skin prick testing (SPT). We aimed to compare these 2 parameters taking as gold standard the surface of the wheal skin response. Patients suspected of having an allergic reaction against inhalant allergens have been skin prick tested using the Pan-European GA(2)LEN SPT panel. Fifteen minutes later, macroscopically evident wheal and flare reactions were marked with a pen and transferred to paper with a transparent scotch tape. Each paper-transferred wheal was scanned with an ordinary scanner, and its surface-corresponding maximum perpendicular diameters and longest diameters were measured using a computer software application for image recognition, developed for this purpose. Correlation coefficients (Spearman's rho) between surfaces and respective mean (rho(mean)) or longest (rho(longest)) diameters were calculated and subsequently compared. 1,554 SPTs were performed in 74 patients. In 264, a macroscopically evident wheal and flare response was observed. Both mean and longest diameters correlated significantly with the wheal surfaces. However, rho(longest) was statistically significantly larger than rho(mean) when the surface of the wheal was >17 mm(2) (rho(longest) > 0.860 vs. rho(mean) < 0.660; p < 0.05).Such a surface corresponds to a maximum diameter of approximately 7 mm and a mean diameter of approximately 6 mm. Thus, the larger the surface of the wheal, the more appropriate the usage of the longest diameter. The longest wheal diameter alone seems to be a better surrogate marker of the wheal surface in comparison with the mean diameter. In addition, it is easier and faster to measure. Therefore, we propose this as the optimal methodology to evaluate SPTs. 2009 S. Karger AG, Basel.
Detector Sampling of Optical/IR Spectra: How Many Pixels per FWHM?

NASA Astrophysics Data System (ADS)

Robertson, J. Gordon

2017-08-01

Most optical and IR spectra are now acquired using detectors with finite-width pixels in a square array. Each pixel records the received intensity integrated over its own area, and pixels are separated by the array pitch. This paper examines the effects of such pixellation, using computed simulations to illustrate the effects which most concern the astronomer end-user. It is shown that coarse sampling increases the random noise errors in wavelength by typically 10-20 % at 2 pixels per Full Width at Half Maximum, but with wide variation depending on the functional form of the instrumental Line Spread Function (i.e. the instrumental response to a monochromatic input) and on the pixel phase. If line widths are determined, they are even more strongly affected at low sampling frequencies. However, the noise in fitted peak amplitudes is minimally affected by pixellation, with increases less than about 5%. Pixellation has a substantial but complex effect on the ability to see a relative minimum between two closely spaced peaks (or relative maximum between two absorption lines). The consistent scale of resolving power presented by Robertson to overcome the inadequacy of the Full Width at Half Maximum as a resolution measure is here extended to cover pixellated spectra. The systematic bias errors in wavelength introduced by pixellation, independent of signal/noise ratio, are examined. While they may be negligible for smooth well-sampled symmetric Line Spread Functions, they are very sensitive to asymmetry and high spatial frequency sub-structure. The Modulation Transfer Function for sampled data is shown to give a useful indication of the extent of improperly sampled signal in an Line Spread Function. The common maxim that 2 pixels per Full Width at Half Maximum is the Nyquist limit is incorrect and most Line Spread Functions will exhibit some aliasing at this sample frequency. While 2 pixels per Full Width at Half Maximum is nevertheless often an acceptable minimum for moderate signal/noise work, it is preferable to carry out simulations for any actual or proposed Line Spread Function to find the effects of various sampling frequencies. Where spectrograph end-users have a choice of sampling frequencies, through on-chip binning and/or spectrograph configurations, it is desirable that the instrument user manual should include an examination of the effects of the various choices.
A New Approach to Measure Contact Angle and Evaporation Rate with Flow Visualization in a Sessile Drop

NASA Technical Reports Server (NTRS)

Zhang, Nengli; Chao, David F.

1999-01-01

The contact angle and the spreading process of sessile droplet are very crucial in many technological processes, such as painting and coating, material processing, film-cooling applications, lubrication, and boiling. Additionally, as it is well known that the surface free energy of polymers cannot be directly, measured for their elastic and viscous restraints. The measurements of liquid contact angle on the polymer surfaces become extremely important to evaluate the surface free energy of polymers through indirect methods linked with the contact angle data. Due to the occurrence of liquid evaporation is inevitable, the effects of evaporation on the contact angle and the spreading become very important for more complete understanding of these processes. It is of interest to note that evaporation can induce Marangoni-Benard convection in sessile drops. However, the impacts of the inside convection on the wetting and spreading processes are not clear. The experimental methods used by previous investigators cannot simultaneously measure the spreading process and visualize the convection inside. Based on the laser shadowgraphic system used by the present author, a very simple optical procedure has been developed to measure the contact angle, the spreading speed, the evaporation rate, and to visualize inside convection of a sessile drop simultaneously. Two CCD cameras were used to synchronously record the real-time diameter of the sessile drop, which is essential for determination of both spreading speed and evaporation rate, and the shadowgraphic image magnified by the sessile drop acting as a thin plano-convex lens. From the shadowgraph, the inside convection of the drop can be observed if any and the image outer diameter, which linked to the drop profile, can be measured. Simple equations have been derived to calculate the drop profile, including the instantaneous contact angle, height, and volume of the sessile drop, as well as the evaporation rate. The influence of the inside convection on the wetting and spreading processes can be figured out through comparison of the drop profiles with and without inside convection when the sessile drop is placed at different evaporation conditions.
Influence of shoulder diameter on Temperature and Z-parameter during friction stir welding of Al 6082 alloy

NASA Astrophysics Data System (ADS)

Kishore Mugada, Krishna; Adepu, Kumar

2018-03-01

In this research article, the effect of increasing shoulder diameter on temperature and Zener Holloman (Z)-parameter for friction stir butt welded AA6082-T6 was studied. The temperature at the Advancing side (AS) of weld was measured using the K-Type thermocouple at four different equidistant locations. The developed analytical model is utilized to predict the maximum temperature (Tpeak) during the welding. The strain, strain rate, Z- Parameter for all the shoulders at four distinct locations were evaluated. The temperature increases with increase in shoulder diameter and the maximum temperature was recorded for 24mm shoulder diameter. The computed log Z values are compared with the available process map and results shows that the values are in stable flow region and near to stir zone the values are in Dynamic recrystallization region (DRX). The axial load (Fz) and total tool torque (N-m) are found to be higher for shoulder diameter of 21 mm i.e., 6.3 kN and 56.5 N-m respectively.
A study of the conditions necessary for the onset of mid-latitude spread F

NASA Technical Reports Server (NTRS)

Zinchenko, G. N.

1976-01-01

Ionospheric conditions associated with the initiation of spread F in the mid-latitude ionosphere were observed. The morphology of spread F at Puerto Rico was investigated. Data from 7 nights was examined for Arecibo, five with spread F and two without. The relative height of the F layer maximum and the vertically integreted Pedersen conductivity, the relation between E and F region conductivities, the coupling lengths between the E and F regions, and vertical and horizontal gradients of electron density were examined. At Millstone Hill 13 nights were examined for all of which spread F was observed. The EW and NS velocities and the vertical velocities and the electric ion temperature ratio were examined.
Spread of dwarfmistletoe into Jeffrey pine plantation..

Treesearch

Robert F. Scarpf; J.R. Parmeter

1967-01-01

A study at the Institute of Forest Genetics, Placerville. Calif . showed that dwarfmistletoe could spread from infected overstory ponderosa pine into planted Jeffrey pine--a maximum distance of about 145 feet. About one-third of the trees within this distance were infected after 22 years. The level of infection in the trees remained low. however and the parasite had...
Impact of Metal Droplets: A Numerical Approach to Solidification

NASA Astrophysics Data System (ADS)

Koldeweij, Robin; Mandamparambil, Rajesh; Lohse, Detlef

2016-11-01

Layer-wise deposition of material to produce complex products is a subject of increasing technological relevance. Subsequent deposition of droplets is one of the possible 3d printing technologies to accomplish this. The shape of the solidified droplet is crucial for product quality. We employ the volume-of-fluid method (in the form of the open-source code Gerris) to study liquid metal (in particular tin) droplet impact. Heat transfer has been implemented based on the enthalpy approach for the liquid-solid phase. Solidification is modeled by adding a sink term to the momentum equations, reducing Navier-Stokes to Darcy's law for high solid fraction. Good agreement is found when validating the results against experimental data. We then map out a phase diagram in which we distinguish between solidification behavior based on Weber and Stefan number. In an intermediate impact regime impact, solidification due to a retracting phase occurs. In this regime the maximum spreading diameter almost exclusively depends on Weber number. Droplet shape oscillations lead to a broad variation of the morphology of the solidified droplet and determine the final droplet height. TNO.
Ketamine modulation of the haemodynamic response to spreading depolarization in the gyrencephalic swine brain

PubMed Central

Santos, Edgar; Schöll, Michael; Kunzmann, Kevin; Stock, Christian; Silos, Humberto; Unterberg, Andreas W; Sakowitz, Oliver W

2016-01-01

Spreading depolarization (SD) generates significant alterations in cerebral haemodynamics, which can have detrimental consequences on brain function and integrity. Ketamine has shown an important capacity to modulate SD; however, its impact on SD haemodynamic response is incompletely understood. We investigated the effect of two therapeutic ketamine dosages, a low-dose of 2 mg/kg/h and a high-dose of 4 mg/kg/h, on the haemodynamic response to SD in the gyrencephalic swine brain. Cerebral blood volume, pial arterial diameter and cerebral blood flow were assessed through intrinsic optical signal imaging and laser-Doppler flowmetry. Our findings indicate that frequent SDs caused a persistent increase in the baseline pial arterial diameter, which can lead to a diminished capacity to further dilate. Ketamine infused at a low-dose reduced the hyperemic/vasodilative response to SD; however, it did not alter the subsequent oligemic/vasoconstrictive response. This low-dose did not prevent the baseline diameter increase and the diminished dilative capacity. Only infusion of ketamine at a high-dose suppressed SD and the coupled haemodynamic response. Therefore, the haemodynamic response to SD can be modulated by continuous infusion of ketamine. However, its use in pathological models needs to be explored to corroborate its possible clinical benefit. PMID:27126324
Ketamine modulation of the haemodynamic response to spreading depolarization in the gyrencephalic swine brain.

PubMed

Sánchez-Porras, Renán; Santos, Edgar; Schöll, Michael; Kunzmann, Kevin; Stock, Christian; Silos, Humberto; Unterberg, Andreas W; Sakowitz, Oliver W

2017-05-01

Spreading depolarization (SD) generates significant alterations in cerebral haemodynamics, which can have detrimental consequences on brain function and integrity. Ketamine has shown an important capacity to modulate SD; however, its impact on SD haemodynamic response is incompletely understood. We investigated the effect of two therapeutic ketamine dosages, a low-dose of 2 mg/kg/h and a high-dose of 4 mg/kg/h, on the haemodynamic response to SD in the gyrencephalic swine brain. Cerebral blood volume, pial arterial diameter and cerebral blood flow were assessed through intrinsic optical signal imaging and laser-Doppler flowmetry. Our findings indicate that frequent SDs caused a persistent increase in the baseline pial arterial diameter, which can lead to a diminished capacity to further dilate. Ketamine infused at a low-dose reduced the hyperemic/vasodilative response to SD; however, it did not alter the subsequent oligemic/vasoconstrictive response. This low-dose did not prevent the baseline diameter increase and the diminished dilative capacity. Only infusion of ketamine at a high-dose suppressed SD and the coupled haemodynamic response. Therefore, the haemodynamic response to SD can be modulated by continuous infusion of ketamine. However, its use in pathological models needs to be explored to corroborate its possible clinical benefit.
Can Coulomb repulsion for charged particle beams be overcome?

NASA Astrophysics Data System (ADS)

Retsky, Michael W.

2004-01-01

Mutual repulsion of discrete charged particles or Coulomb repulsion is widely considered to be an ultimate hard limit in charged particle optics. It prevents the ability to finely focus high current beams into a small spots at large distances from the defining apertures. A classic example is the 1970s era "Star Wars" study of an electron beam directed energy weapon as an orbiting antiballistic missile device. After much analysis, it was considered physically impossible to focus a 1000-amp 1-GeV beam into a 1-cm diameter spot 1000-km from the beam generator. The main reason was that a 1-cm diameter beam would spread to 5-m diameter at 1000-km due to Coulomb repulsion. Since this could not be overcome, the idea was abandoned. But is this true? What if the rays were reversed? That is, start with a 5-m beam converging slightly with the same nonuniform angular and energy distribution as the electrons from the original problem were spreading at 1000-km distance. Could Coulomb repulsion be overcome? Looking at the terms in computational studies, some are reversible while others are not. Since the nonreversible terms should be small, it might be possible to construct an electron beam directed energy weapon.
Rheological, physical and sensorial evaluation of cookies supplemented with dairy powders.

PubMed

Sert, Durmuş; Demir, M Kürşat; Ertaş, Nilgün

2016-04-01

The effect of dairy powders (skim milk powder, butter milk powder, sodium caseinate, yoghurt powder, milk powder and colostrum powder) on cookie quality was studied. Cookies were tested for aw, calorimetric energy, diameter, thickness, spread ratio, breaking strength, colour, dough consistency and sensory evaluation. The lowest aw values were obtained for cookies containing colostrum powder; also the highest calorimetric energy values were obtained from the colostrum powder-added cookies. Diameter values of cookies with the addition of skim milk powder, butter milk powder, yoghurt powder and milk powder were higher than that of sodium caseinate and colostrum powder. The lowest spread ratio was measured in the cookie samples with added skim milk powder. The addition of yoghurt powder gave the highest breaking strength of cookies. Cookies with sodium caseinate addition exhibited the highest lightness (L*) values than the other cookies with different dairy powders. Cookies prepared with butter milk powder received the highest scores for colour, appearance, texture, crispness and overall acceptability. © The Author(s) 2015.
Echocolor Doppler morpho-functional study of the jugulo-subclavian confluence in chronic cerebro-spinal venous insufficiency and multiple sclerosis patients.

PubMed

Mandolesi, Sandro; d'Alessandro, Aldo; Desogus, Antonello Ignazio; Ciccone, Marco Matteo; Zito, Annapaola; Stammegna, Immacolata; Niglio, Tarcisio; Orsini, Augusto; Mandolesi, Dimitri; d'Alessandro, Alessandro; Revelli, Luca

2017-01-01

The aim of this work is to measure the mean diameter of the confluence jugulo- subclavian, the impact of different types of jugular confluences and the correlation between the types of confluences and the Valsalva maneuver (jugular reflux) in subjects with Chronic Cerebro-Spinal Venous Insufficiency (CCSVI) and Multiple Sclerosis. We investigated by Echo-Color-Doppler (ECD) 103 subjects (67 F 36M) of mean age 45 ± 12 years (a minimum of 22 to a maximum of 79 years, with a median of 44 and a modal value 42 years), mean EDSS of 4.7 and average disease duration of 12 years. The 103 right jugular veins investigated had an average diameter of 8.4 ± 2.4 mm (minimum 4.0, maximum 14.9 mm; median 7.9; modal value 7.6 mm). Three form types were found: 56 cylindrical, 29 conical and 18 funnel. Valsalva maneuver was positive in 30 patients. The 103 left jugular investigated had an average diameter of 8.9 ± 2.4 mm (minimum 2.8, maximum 14.4 mm; median of 8.8; modal value 8.7 mm). The form types were found: 42 cylindrical, 45 conical and 16 funnel. Valsalva maneuver was positive in 30 patients. The mean diameter of the jugular veins was 8.7 mm. Internal jugular veins with cylindrical morphology have a diameter smaller than other forms; this difference is statistically significant. The different morphology of the jugular vein confluence does not increase the possibility of a reflux because the positive Valsalva maneuvers are not statistically significant when compared to the various types. CCSVI, EchoColorDoppler Map, Jugulo-Subclavian Confluence Diameter.
Stocking and structure for maximum growth in sugar maple selection stands.

Treesearch

Thomas R. Crow; Carl H. Tubbs; Rodney D. Jacobs; Robert R. Oberg

1981-01-01

The impacts of stocking, structure, and cutting cycle on basal area, cubic foot volume, board foot volume, and diameter growth are considered. Recommendations are provided for maximum growth in uneven-aged sugar maple stands.

From Relativistic Electrons to X-ray Phase Contrast Imaging

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

Lumpkin, A. H.; Garson, A. B.; Anastasio, M. A.

2017-10-09

We report the initial demonstrations of the use of single crystals in indirect x-ray imaging for x-ray phase contrast imaging at the Washington University in St. Louis Computational Bioimaging Laboratory (CBL). Based on single Gaussian peak fits to the x-ray images, we observed a four times smaller system point spread function (21 μm (FWHM)) with the 25-mm diameter single crystals than the reference polycrystalline phosphor’s 80-μm value. Potential fiber-optic plate depth-of-focus aspects and 33-μm diameter carbon fiber imaging are also addressed.
Synthesis and characterization of silver/diatomite nanocomposite by electron beam irradiation

NASA Astrophysics Data System (ADS)

Hanh, Truong Thi; Thu, Nguyen Thi; Quoc, Le Anh; Hien, Nguyen Quoc

2017-10-01

Silver nanoparticles (AgNPs) with diameter about 9 nm were deposited on diatomite by irradiation under electron beam of diatomite suspension containing 10 mM AgNO3 in 1% chitosan solution, at the dose of 20.2 kGy. The AgNPs/diatomite nanocomposite was characterized by UV-Vis spectroscopy, TEM image and energy dispersive X-ray spectroscopy (EDX). The antibacterial activity of the AgNPs/diatomite against E. coli and S. aureus was evaluated by reduction of bacterial colonies on spread plates and inhibition zone diameter on diffusion disks.
Oxidation at through-hole defects in fused slurry silicide coated columbium alloys FS-85 and Cb-752

NASA Technical Reports Server (NTRS)

Levine, S. R.

1973-01-01

Metal recession and interstitial contamination at 0.08-centimeter-diameter through-hole intentional defects in fused slurry silicide coated FS-85 and Cb-752 columbium alloys were studied to determine the tolerance of these materials to coating defects. Five external pressure reentry simulation exposures to 1320 C and 4.7 x 1,000 N/sq m (maximum pressure) resulted in a consumed metal zone having about twice the initial defect diameter for both alloys with an interstitial contamination zone extending about three to four initial defect diameters. Self-healing occurred in the 1.33 x 10 N/sq m, 1320 C exposures and to a lesser extent in internal pressure reentry cycles to 1320 C and 1.33 x 100 N/sq m (maximum pressure).
Aldosterone mediates metastatic spread of renal cancer via the G protein-coupled estrogen receptor (GPER).

PubMed

Feldman, Ross D; Ding, Qingming; Hussain, Yasin; Limbird, Lee E; Pickering, J Geoffrey; Gros, Robert

2016-06-01

Although aldosterone is a known regulator of renal and cardiovascular function, its role as a regulator of cancer growth and spread has not been widely considered. This study tested the hypothesis that aldosterone regulates cancer cell growth/spread via G protein-coupled estrogen receptor (GPER) activation. In vitro in murine renal cortical adenocarcinoma (RENCA) cells, a widely used murine in vitro model for the study of renal cell adenocarcinoma, aldosterone increased RENCA cell proliferation to a maximum of 125 ± 3% of control at a concentration of 10 nM, an effect blocked by the GPER antagonist G15 or by GPER knockdown using short interfering (sh) RNA techniques. Further, aldosterone increased RENCA cell migration to a maximum of 170 ± 20% of control at a concentration of 100 nM, an effect also blocked by G15 or by GPER down-regulation. In vivo, after orthotopic RENCA cell renal transplantation, pulmonary tumor spread was inhibited by pharmacologic blockade of aldosterone effects with spironolactone (percentage of lung occupied by metastasis: control = 68 ± 13, spironolactone = 26 ± 8, P < 0.05) or inhibition of aldosterone synthesis with a high dietary salt diet (percentage of lung: control = 44 ± 6, high salt = 12 ± 3, P < 0.05), without reducing primary tumor size. Additionally, adrenalectomy significantly reduced the extent of pulmonary tumor spread, whereas aldosterone infusion recovered pulmonary metastatic spread toward baseline levels. Finally, inhibition of GPER either with the GPER antagonist G15 or by GPER knockdown comparably inhibited RENCA cell pulmonary metastatic cancer spread. Taken together, these findings provide strong evidence for aldosterone serving a causal role in renal cell cancer regulation via its GPER receptor; thus, antagonism of GPER represents a potential new target for treatment to reduce metastatic spread.-Feldman, R. D., Ding, Q., Hussain, Y., Limbird, L. E., Pickering, J. G., Gros, R. Aldosterone mediates metastatic spread of renal cancer via the G protein-coupled estrogen receptor (GPER). © FASEB.
Digital terrestrial photogrammetric methods for tree stem analysis

Treesearch

Neil A. Clark; Randolph H. Wynne; Daniel L. Schmoldt; Matt Winn

2000-01-01

A digital camera was used to measure diameters at various heights along the stem on 20 red oak trees. Diameter at breast height ranged from 16 to over 60 cm, and height to a 10-cm top ranged from 12 to 20 m. The chi-square maximum anticipated error of geometric mean diameter estimates at the 95 percent confidence level was within ±4 cm for all heights when...
40 CFR 302.6 - Notification requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ash, bottom ash, and boiler slags), including the dumping and land spreading operations that occur..., bottom ash, and boiler slags. (d) Except for releases of radionuclides, notification of the release of an..., selenium, silver, thallium, or zinc is not required if the mean diameter of the particles released is...
Rumor Spreading Model with Trust Mechanism in Complex Social Networks

NASA Astrophysics Data System (ADS)

Wang, Ya-Qi; Yang, Xiao-Yuan; Han, Yi-Liang; Wang, Xu-An

2013-04-01

In this paper, to study rumor spreading, we propose a novel susceptible-infected-removed (SIR) model by introducing the trust mechanism. We derive mean-field equations that describe the dynamics of the SIR model on homogeneous networks and inhomogeneous networks. Then a steady-state analysis is conducted to investigate the critical threshold and the final size of the rumor spreading. We show that the introduction of trust mechanism reduces the final rumor size and the velocity of rumor spreading, but increases the critical thresholds on both networks. Moreover, the trust mechanism not only greatly reduces the maximum rumor influence, but also postpones the rumor terminal time, which provides us with more time to take measures to control the rumor spreading. The theoretical results are confirmed by sufficient numerical simulations.
Scattering and the Point Spread Function of the New Generation Space Telescope

NASA Technical Reports Server (NTRS)

Schreur, Julian J.

1996-01-01

Preliminary design work on the New Generation Space Telescope (NGST) is currently under way. This telescope is envisioned as a lightweight, deployable Cassegrain reflector with an aperture of 8 meters, and an effective focal length of 80 meters. It is to be folded into a small-diameter package for launch by an Atlas booster, and unfolded in orbit. The primary is to consist of an octagon with a hole at the center, and with eight segments arranged in a flower petal configuration about the octagon. The comers of the petal-shaped segments are to be trimmed so that the package will fit atop the Atlas booster. This mirror, along with its secondary will focus the light from a point source into an image which is spread from a point by diffraction effects, figure errors, and scattering of light from the surface. The distribution of light in the image of a point source is called a point spread function (PSF). The obstruction of the incident light by the secondary mirror and its support structure, the trimmed corners of the petals, and the grooves between the segments all cause the diffraction pattern characterizing an ideal point spread function to be changed, with the trimmed comers causing the rings of the Airy pattern to become broken up, and the linear grooves causing diffraction spikes running radially away from the central spot, or Airy disk. Any figure errors the mirror segments may have, or any errors in aligning the petals with the central octagon will also spread the light out from the ideal point spread function. A point spread function for a mirror the size of the NGST and having an incident wavelength of 900 nm is considered. Most of the light is confined in a circle with a diameter of 0.05 arc seconds. The ring pattern ranges in intensity from 10(exp -2) near the center to 10(exp -6) near the edge of the plotted field, and can be clearly discerned in a log plot of the intensity. The total fraction of the light scattered from this point spread function is called the total integrated scattering (TIS), and the fraction remaining is called the Strehl ratio. The angular distribution of the scattered light is called the angle resolved scattering (ARS), and it shows a strong spike centered on a scattering angle of zero, and a broad , less intense distribution at larger angles. It is this scattered light, and its effect on the point spread function which is the focus of this study.
Estimation of the Mean Axon Diameter and Intra-axonal Space Volume Fraction of the Human Corpus Callosum: Diffusion q-space Imaging with Low q-values.

PubMed

Suzuki, Yuriko; Hori, Masaaki; Kamiya, Kouhei; Fukunaga, Issei; Aoki, Shigeki; VAN Cauteren, Marc

2016-01-01

Q-space imaging (QSI) is a diffusion-weighted imaging (DWI) technique that enables investigation of tissue microstructure. However, for sufficient displacement resolution to measure the microstructure, QSI requires high q-values that are usually difficult to achieve with a clinical scanner. The recently introduced "low q-value method" fits the echo attenuation to only low q-values to extract the root mean square displacement. We investigated the clinical feasibility of the low q-value method for estimating the microstructure of the human corpus callosum using a 3.0-tesla clinical scanner within a clinically feasible scan time. We performed a simulation to explore the acceptable range of maximum q-values for the low q-value method. We simulated echo attenuations caused by restricted diffusion in the intra-axonal space (IAS) and hindered diffusion in the extra-axonal space (EAS) assuming 100,000 cylinders with various diameters, and we estimated mean axon diameter, IAS volume fraction, and EAS diffusivity by fitting echo attenuations with different maximum q-values. Furthermore, we scanned the corpus callosum of 7 healthy volunteers and estimated the mean axon diameter and IAS volume fraction. Good agreement between estimated and defined values in the simulation study with maximum q-values of 700 and 800 cm(-1) suggested that the maximum q-value used in the in vivo experiment, 737 cm(-1), was reasonable. In the in vivo experiment, the mean axon diameter was larger in the body of the corpus callosum and smaller in the genu and splenium, and this anterior-to-posterior trend is consistent with previously reported histology, although our mean axon diameter seems larger in size. On the other hand, we found an opposite anterior-to-posterior trend, with high IAS volume fraction in the genu and splenium and a lower fraction in the body, which is similar to the fiber density reported in the histology study. The low q-value method may provide insights into tissue microstructure using a 3T clinical scanner within clinically feasible scan time.
Evaluation of the amperex 56 TVP photomultiplier. [characteristics: photoelectron time spread, anode pulse amplitude and photocathode sensing area

NASA Technical Reports Server (NTRS)

Lo, C. C.; Leskovar, B.

1976-01-01

Characteristics were measured for the Amperex 56 TVP 42 mm-diameter photomultiplier. Some typical photomultiplier characteristics-such as gain, dark current, transit and rise times-are compared with data provided. Photomultiplier characteristics generally not available such as the single photoelectron time spread, the relative collection efficiency, the relative anode pulse amplitude as a function of the voltage between the photocathode and focusing electrode, and the position of the photocathode sensing area were measured and are discussed for two 56 TVP's. The single photoelectron time spread, the relative collection efficiency, and the transit time difference as a function of the voltage between photocathode and focusing electrode were also measured and are discussed, particularly with respect to the optimization of photomultiplier operating conditions for timing applications.
Viscous drop collisions on surfaces of varying wettability

NASA Astrophysics Data System (ADS)

Bolleddula, Daniel; Berchielli, Al; Aliseda, Alberto

2010-11-01

We present an experimental study of increasingly viscous acetone rich and Newtonian equivalent liquid drops colliding on surfaces of varying wettability. This class of liquids applies directly to spray coating processes in pharmaceutical industries. The results from this study will elucidate the physics in a regime where resisting viscous forces and the restoring forces of capillarity are balanced, Oh˜ 1. Early spreading dynamics τ=Ut/D 1 indicate negligible dependence on contact angles while longer times demonstrate deviations from Tanner's law, D˜t^1/10. We will compare our results with recent theory to demonstrate the feasibility of modelling complex rheology spreading characteristics over short and long time scales. Preliminary results indicate an intermediate spreading regime following the inertial phase where the diameter, D˜t^n with 1/7 < n < 1/5.
Renal Cell Carcinoma: Comparison of RENAL Nephrometry and PADUA Scores with Maximum Tumor Diameter for Prediction of Local Recurrence after Thermal Ablation.

PubMed

Maxwell, Aaron W P; Baird, Grayson L; Iannuccilli, Jason D; Mayo-Smith, William W; Dupuy, Damian E

2017-05-01

Purpose To evaluate the performance of the radius, exophytic or endophytic, nearness to collecting system or sinus, anterior or posterior, and location relative to polar lines (RENAL) nephrometry and preoperative aspects and dimensions used for anatomic classification (PADUA) scoring systems and other tumor biometrics for prediction of local tumor recurrence in patients with renal cell carcinoma after thermal ablation. Materials and Methods This HIPAA-compliant study was performed with a waiver of informed consent after institutional review board approval was obtained. A retrospective evaluation of 207 consecutive patients (131 men, 76 women; mean age, 71.9 years ± 10.9) with 217 biopsy-proven renal cell carcinoma tumors treated with thermal ablation was conducted. Serial postablation computed tomography (CT) or magnetic resonance (MR) imaging was used to evaluate for local tumor recurrence. For each tumor, RENAL nephrometry and PADUA scores were calculated by using imaging-derived tumor morphologic data. Several additional tumor biometrics and combinations thereof were also measured, including maximum tumor diameter. The Harrell C index and hazard regression techniques were used to quantify associations with local tumor recurrence. Results The RENAL (hazard ratio, 1.43; P = .003) and PADUA (hazard ratio, 1.80; P < .0001) scores were found to be significantly associated with recurrence when regression techniques were used but demonstrated only poor to fair discrimination according to Harrell C index results (C, 0.68 and 0.75, respectively). Maximum tumor diameter showed the highest discriminatory strength of any individual variable evaluated (C, 0.81) and was also significantly predictive when regression techniques were used (hazard ratio, 2.98; P < .0001). For every 1-cm increase in diameter, the estimated rate of recurrence risk increased by 198%. Conclusion Maximum tumor diameter demonstrates superior performance relative to existing tumor scoring systems and other evaluated biometrics for prediction of local tumor recurrence after renal cell carcinoma ablation. © RSNA, 2016.
Measuring stone volume - three-dimensional software reconstruction or an ellipsoid algebra formula?

PubMed

Finch, William; Johnston, Richard; Shaida, Nadeem; Winterbottom, Andrew; Wiseman, Oliver

2014-04-01

To determine the optimal method for assessing stone volume, and thus stone burden, by comparing the accuracy of scalene, oblate, and prolate ellipsoid volume equations with three-dimensional (3D)-reconstructed stone volume. Kidney stone volume may be helpful in predicting treatment outcome for renal stones. While the precise measurement of stone volume by 3D reconstruction can be accomplished using modern computer tomography (CT) scanning software, this technique is not available in all hospitals or with routine acute colic scanning protocols. Therefore, maximum diameters as measured by either X-ray or CT are used in the calculation of stone volume based on a scalene ellipsoid formula, as recommended by the European Association of Urology. In all, 100 stones with both X-ray and CT (1-2-mm slices) were reviewed. Complete and partial staghorn stones were excluded. Stone volume was calculated using software designed to measure tissue density of a certain range within a specified region of interest. Correlation coefficients among all measured outcomes were compared. Stone volumes were analysed to determine the average 'shape' of the stones. The maximum stone diameter on X-ray was 3-25 mm and on CT was 3-36 mm, with a reasonable correlation (r = 0.77). Smaller stones (<9 mm) trended towards prolate ellipsoids ('rugby-ball' shaped), stones of 9-15 mm towards oblate ellipsoids (disc shaped), and stones >15 mm towards scalene ellipsoids. There was no difference in stone shape by location within the kidney. As the average shape of renal stones changes with diameter, no single equation for estimating stone volume can be recommended. As the maximum diameter increases, calculated stone volume becomes less accurate, suggesting that larger stones have more asymmetric shapes. We recommend that research looking at stone clearance rates should use 3D-reconstructed stone volumes when available, followed by prolate, oblate, or scalene ellipsoid formulas depending on the maximum stone diameter. © 2013 The Authors. BJU International © 2013 BJU International.
Investigating the Relation between Sunspots and Umbral Dots

NASA Astrophysics Data System (ADS)

Yadav, Rahul; Louis, Rohan E.; Mathew, Shibu K.

2018-03-01

Umbral dots (UDs) are transient, bright features observed in the umbral region of a sunspot. We study the physical properties of UDs observed in sunspots of different sizes. The aim of our study is to relate the physical properties of UDs with the large-scale properties of sunspots. For this purpose, we analyze high-resolution G-band images of 42 sunspots observed by Hinode/SOT, located close to disk center. The images were corrected for instrumental stray light and restored with the modeled point-spread function. An automated multilevel tracking algorithm was employed to identify the UDs located in selected G-band images. Furthermore, we employed Solar Dynamics Observatory/HMI, limb-darkening-corrected, full-disk continuum images to estimate the sunspot phase and epoch for the selected sunspots. The number of UDs identified in different umbrae exhibits a linear relation to the umbral size. The observed filling factor ranges from 3% to 7% and increases with the mean umbral intensity. Moreover, the filling factor shows a decreasing trend with the umbral size. We also found that the observed mean and maximum intensities of UDs are correlated with the mean umbral intensity. However, we do not find any significant relationship between the mean (and maximum) intensity and effective diameter of UDs and the sunspot area, epoch, and decay rate. We suggest that this lack of relation could be due to either the distinct transition of spatial scales associated with overturning convection in the umbra or the shallow depth associated with UDs, or both.
Plasma Effects on Fast Pair Beams. II. Reactive versus Kinetic Instability of Parallel Electrostatic Waves

NASA Astrophysics Data System (ADS)

Schlickeiser, R.; Krakau, S.; Supsar, M.

2013-11-01

The interaction of TeV gamma-rays from distant blazars with the extragalactic background light produces relativistic electron-positron pair beams by the photon-photon annihilation process. Using the linear instability analysis in the kinetic limit, which properly accounts for the longitudinal and the small but finite perpendicular momentum spread in the pair momentum distribution function, the growth rate of parallel propagating electrostatic oscillations in the intergalactic medium is calculated. Contrary to the claims of Miniati and Elyiv, we find that neither the longitudinal nor the perpendicular spread in the relativistic pair distribution function significantly affect the electrostatic growth rates. The maximum kinetic growth rate for no perpendicular spread is even about an order of magnitude greater than the corresponding reactive maximum growth rate. The reduction factors in the maximum growth rate due to the finite perpendicular spread in the pair distribution function are tiny and always less than 10-4. We confirm earlier conclusions by Broderick et al. and our group that the created pair beam distribution function is quickly unstable in the unmagnetized intergalactic medium. Therefore, there is no need to require the existence of small intergalactic magnetic fields to scatter the produced pairs, so that the explanation (made by several authors) for the Fermi non-detection of the inverse Compton scattered GeV gamma-rays by a finite deflecting intergalactic magnetic field is not necessary. In particular, the various derived lower bounds for the intergalactic magnetic fields are invalid due to the pair beam instability argument.
Diameter Effect Curve and Detonation Front Curvature Measurements for ANFO

NASA Astrophysics Data System (ADS)

Catanach, R. A.; Hill, L. G.

2001-06-01

Diameter effect and front curvature measurements are reported for rate stick experiments on commercially available prilled ANFO (ammonium nitrate-fuel oil) at ambient temperature. The shots were fired in paper tubes so as to provide minimal confinement. Diameters ranged from 77 mm. (≈ failure diameter) to 200 mm., with the tube length being ten diameters in all cases. Each detonation wave shape was fit with an analytic form, from which the local normal velocity Dn and total curvature κ were generated as a function of radius R, then plotted parametrically to generate a D_n(κ) function. The resulting behavior deviates substantially from that of previous explosives,(Hill,L.G., Bdzil,J.B., and Aslam,T.D., 11^th) Detonation Symposium, 1998^,(Hill,L.G., Bdzil,J.B., Davis,W.C., and Engelke,R., Shock Compression of Condensed Matter, 1999) in which curves for different stick sizes overlay well for small κ but diverge for large κ, and for which κ increases monotonically with R to achieve a maximum value at the charge edge. For ANFO, we find that κ achieves a maximum at an intermediate R and that D_n(κ) curves for different stick sizes are widely separated with no overlap whatsoever.
Determining water sensitive card spread factors for real world tank mixes

USDA-ARS?s Scientific Manuscript database

The use of water sensitive cards provides a quick and easy method to sample the coverage and deposition from spray applications. Typically, this measure is limited to percent coverage as measures of droplet size, and thus deposition rate, are highly influenced by the stain diameter resulting from t...
Droplet evaporation and spread on waxy and hairy leaves associated with type and concentration of adjuvants

USDA-ARS?s Scientific Manuscript database

Adjuvants can improve pesticide application efficiency and effectiveness. However, knowledge is lacking on quantitative behaviors of adjuvant-amended pesticide droplets on foliage. Evaporation rates and wetted areas of 500 µm diameter water droplets amended with four adjuvants applied to waxy and h...
Growth and Survival of Northern Hardwood Sprouts After Burning

Treesearch

Donald A. Perala

1974-01-01

Root collar sprouting of nine hardwoods was measured annually after a prescribed burn. Basswood, red oak, and paper birch were the most vigorous sprouters; sugar maple and yellow birch the least; and American elm, bur oak, ironwood and red maple were intermediate. Parent tree diameter influenced spreading.
The search for valved conduit tissue grafts for adults (>22 mm): an ultrasonographic study of jugular vein diameters of horses and cattle

PubMed Central

Schwarzwald, Colin C; Jenni, Rolf

2009-01-01

Background Natural heterologous valved conduits with a diameter greater than 22 mm that can be used for right ventricular outflow tract reconstruction in adults are not commercially available. The purpose of this study was to measure by ultrasonography the maximum diameter of the distended jugular veins of horses and cattle, respectively, to identify a population of animals that would be suitable for post-mortem collection of jugular veins at sizes greater than 22 mm. Methods The study population included 60 Warmblood horses, 25 Freiberger horses, 20 Brown Swiss cows, and 20 Holstein cows (including 10 Holstein and 10 Red Holstein). The maximum cross-sectional diameter of the distended jugular veins was measured at a location half-way between the mandibular angle and the thoracic inlet. The thoracic circumference (heart girth length) was used as a surrogate of body size. The jugular vein diameters of the different populations were compared by analysis of variance and the association between heart girth length and jugular vein diameter was determined in each of the four study populations by linear regression analysis. Results There was considerable individual variation of jugular vein diameters within each of the four study populations. There was no statistically significant relationship between thoracic circumference and jugular vein diameter in any of the populations. The jugular vein diameters of Brown Swiss cows were significantly larger than those of any of the other populations. Warmblood horses had significantly larger jugular vein diameters compared to Freiberger horses. Conclusion The results of this study suggest that the production of bovine or equine xenografts with diameters of greater than 22 mm would be feasible. Differences between species and breeds need to be considered. However, prediction of the jugular vein diameter based on breed and heart girth length in an individual animal is inaccurate. PMID:19678940

7 CFR 51.320 - Diameter.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Standards for Grades of Apples Definitions § 51.320 Diameter. When measuring for minimum size, “diameter” means the greatest dimension of the apple measured at right angles to a line from stem to blossom end. When measuring for maximum size, “diameter” means the smallest dimension of the apple determined by...
7 CFR 51.320 - Diameter.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Standards for Grades of Apples Definitions § 51.320 Diameter. When measuring for minimum size, “diameter” means the greatest dimension of the apple measured at right angles to a line from stem to blossom end. When measuring for maximum size, “diameter” means the smallest dimension of the apple determined by...
7 CFR 51.320 - Diameter.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Standards for Grades of Apples Definitions § 51.320 Diameter. When measuring for minimum size, “diameter” means the greatest dimension of the apple measured at right angles to a line from stem to blossom end. When measuring for maximum size, “diameter” means the smallest dimension of the apple determined by...
Growth and yield of Giant Sequoia

Treesearch

David J. Dulitz

1986-01-01

Very little information exists concerning growth and yield of giant sequoia (Sequoiadendron giganteum [Lindl.] Buchholz). For old-growth trees, diameter growth is the single factor adding increment since maximum height has been obtained. Diameter growth averages 0.04 inches per year in normal old-growth trees but will fluctuate with changes in the...
Aneurysm Characteristics Associated with the Rupture Risk of Intracranial Aneurysms: A Self-Controlled Study.

PubMed

Kang, Huibin; Ji, Wenjun; Qian, Zenghui; Li, Youxiang; Jiang, Chuhan; Wu, Zhongxue; Wen, Xiaolong; Xu, Wenjuan; Liu, Aihua

2015-01-01

This study analyzed the rupture risk of intracranial aneurysms (IAs) according to aneurysm characteristics by comparing the differences between two aneurysms in different locations within the same patient. We utilized this self-controlled model to exclude potential interference from all demographic factors to study the risk factors related to IA rupture. A total of 103 patients were diagnosed with IAs between January 2011 and April 2015 and were enrolled in this study. All enrolled patients had two IAs. One IA (the case) was ruptured, and the other (the control) was unruptured. Aneurysm characteristics, including the presence of a daughter sac, the aneurysm neck, the parent artery diameter, the maximum aneurysm height, the maximum aneurysm width, the location, the aspect ratio (AR, maximum perpendicular height/average neck diameter), the size ratio (SR, maximum aneurysm height/average parent diameter) and the width/height ratio (WH ratio, maximum aneurysm width/maximum aneurysm height), were collected and analyzed to evaluate the rupture risks of the two IAs within each patient and to identify the independent risk factors associated with IA rupture. Multivariate, conditional, backward, stepwise logistic regression analysis was performed to identify the independent risk factors associated with IA rupture. The multivariate analysis identified the presence of a daughter sac (odds ratio [OR], 13.80; 95% confidence interval [CI], 1.65-115.87), a maximum aneurysm height ≥7 mm (OR, 4.80; 95% CI, 1.21-18.98), location on the posterior communicating artery (PCOM) or anterior communicating artery (ACOM; OR, 3.09; 95% CI, 1.34-7.11) and SR (OR, 2.13; 95% CI, 1.16-3.91) as factors that were significantly associated with IA rupture. The presence of a daughter sac, the maximum aneurysm height, PCOM or ACOM locations and SR (>1.5±0.7) of unruptured IAs were significantly associated with IA rupture.
Spread of dwarf mistletoe from discrete seed sources into young stands of ponderosa and Jeffrey pines

Treesearch

J. R. Parmeter Jr.

1972-01-01

The maximum distance of spread of dwarf mistletoes from isolated overstory pines into surrounding reproduction averages 120 feet. The rate of infection in young trees declined as distance from the seed source increased and was generally greatest in the direction of prevailing winds. This pattern of infection was similar to the previously reported pattern of seed...
Population buildup and vertical spread of dwarf mistletoe on young red and white firs in California

Treesearch

Robert F. Scharpf; John R. Parmeter Jr.

1976-01-01

Rate of population buildup of dwarf mistletoe, Arceuthobium abietinum Engelm. ex Munz., was slow in most small red firs and white firs 12 to 15 years after inoculation with the parasite. Where population buildup did occur, it remained clustered in the lower portions of tree crowns near inoculation sites. Maximum distance of vertical spread was 16...
Plasma studies of the permanent magnet electron cyclotron resonance ion source at Peking University.

PubMed

Ren, H T; Peng, S X; Xu, Y; Zhao, J; Lu, P N; Chen, J; Zhang, A L; Zhang, T; Guo, Z Y; Chen, J E

2014-02-01

At Peking University (PKU) we have developed several 2.45 GHz Permanent Magnet Electron Cyclotron Resonance ion sources for PKUNIFTY, SFRFQ, Coupled RFQ&SFRFQ, and Dielectric-Wall Accelerator (DWA) projects (respectively, 50 mA of D(+), 10 mA of O(+), 10 mA of He(+), and 50 mA of H(+)). In order to improve performance of these ion sources, it is necessary to better understand the principal factors that influence the plasma density and the atomic ion fraction. Theoretical analysis about microwave transmission and cut-off inside the discharge chamber were carried out to study the influence of the discharge chamber diameters. As a consequence, experimental studies on plasma density and ion fraction with different discharge chamber sizes have been carried out. Due to the difficulties in measuring plasma density inside the discharge chamber, the output beam current was measured to reflect the plasma density. Experimental results show that the plasma density increases to the maximum and then decreases significantly as the diameter changed from 64 mm to 30 mm, and the atomic ion fraction has the same tendency. The maximum beam intensity was obtained with the diameter of 35 mm, but the maximum atomic ion fraction with a diameter of 40 mm. The experimental results are basically accordant with the theoretical calculation. Details are presented in this paper.
Growth of ponderosa pine seedlings as affected by air pollution

NASA Astrophysics Data System (ADS)

Momen, B.; Anderson, P. D.; Houpis, J. L. J.; Helms, J. A.

The effect of air pollution on seedling survival and competitive ability is important to natural and artificial regeneration of forest trees. Although biochemical and physiological processes are sensitive indicators of pollution stress, the cumulative effects of air pollutants on seedling vigor and competitive ability may be assessed directly from whole-plant growth characteristics such as diameter, height, and photosynthetic area. A few studies that have examined intraspecific variation in seedling response to air pollution indicate that genotypic differences are important in assessing potential effects of air pollution on forest regeneration. Here, we studied the effects of acid rain (no-rain, pH 5.1 rain, pH 3.0 rain) and ozone (filtered, ambient, twice-ambient) in the field on height, diameter, volume, the height:diameter ratio, maximum needle length, and time to reach maximum needle length in seedlings of three families of ponderosa pine ( Pinus ponderosa Dougl. ex Laws). Seedling diameter, height, volume, and height:diameter ratio related significantly to their pre-treatment values. Twice-ambient ozone decreased seedling diameter compared with ozone-filtered air. A significant family-by-ozone interaction was detected for seedling height, as the height of only one of the three families was decreased by twice-ambient ozone compared with the ambient level. Seedling diameter was larger and the height:diameter ratio was smaller under pH 3.0 rain compared to either the no-rain or the pH 5.1-rain treatment. This suggests greater seedling vigor, perhaps due to a foliar fertilization effect of the pH 3.0 rain.
Crustal accretion along the global mid-ocean ridge system based on basaltic glass and olivine-hosted melt inclusion compositions

NASA Astrophysics Data System (ADS)

Wanless, V. D.; Behn, M. D.

2015-12-01

The depth and distribution of crystallization at mid-ocean ridges controls the overall architecture of the oceanic crust, influences hydrothermal circulation, and determines geothermal gradients in the crust and uppermost mantle. Despite this, there is no overall consensus on how crystallization is distributed within the crust/upper mantle or how this varies with spreading rate. Here, we examine crustal accretion at mid-ocean ridges by combining crystallization pressures calculated from major element barometers on mid-ocean ridge basalt (MORB) glasses with vapor-saturation pressures from melt inclusions to produce a detailed map of crystallization depths and distributions along the global ridge system. We calculate pressures of crystallization from >11,500 MORB glasses from the global ridge system using two established major element barometers (1,2). Additionally, we use vapor-saturation pressures from >400 olivine-hosted melt inclusions from five ridges with variable spreading rates to constrain pressures and distributions of crystallization along the global ridge system. We show that (i) crystallization depths from MORB glasses increase and become less focused with decreasing spreading rate, (ii) maximum glass pressures are greater than the maximum melt inclusion pressure, which indicates that the melt inclusions do not record the deepest crystallization at mid-ocean ridges, and (iii) crystallization occurs in the lower crust/upper mantle at all ridges, indicating accretion is distributed throughout the crust at all spreading rates, including those with a steady-state magma lens. Finally, we suggest that the remarkably similar maximum vapor-saturation pressures (~ 3000 bars) in melt inclusion from all spreading rates reflects the CO2 content of the depleted upper mantle feeding the global mid-ocean ridge system. (1) Michael, P. & W. Cornell (1998), Journal of Geophysical Research, 103(B8), 18325-18356; (2) Herzberg, C. (2004), Journal of Petrology, 45(12), 2389.
Transmission characteristics of femtosecond optical pulses in hollow-core fibers

NASA Astrophysics Data System (ADS)

Mohebbi, Mohammad

2005-09-01

Hollow-core fibers with fused silica and metal claddings are studied for transmission of femtosecond optical pulses at a wavelength of 800 nm. The measured transmission loss of a silver-coated hollow fiber with a core diameter of 250 μm is 0.44 dB/m. A bending loss of 1.1 dB/m was measured for this waveguide with a radius of curvature of 1 m. It is shown that the fundamental hybrid mode HE 11 has negligible pulse spreading. In the presence of higher order modes modal dispersion becomes dominant and depends strongly on the core diameter.
Coulomb repulsion and the electron beam directed energy weapon

NASA Astrophysics Data System (ADS)

Retsky, Michael W.

2004-09-01

Mutual repulsion of discrete charged particles or Coulomb repulsion is widely considered to be an ultimate hard limit in charged particle optics. It prevents the ability to finely focus high current beams into small spots at large distances from defining apertures. A classic example is the 1970s era "Star Wars" study of an electron beam directed energy weapon as an orbiting antiballistic missile device. After much analysis, it was considered physically impossible to focus a 1000-amp 1-GeV beam into a 1-cm diameter spot 1000-km from the beam generator. The main reason was that a 1-cm diameter beam would spread to 5-m diameter at 1000-km due to Coulomb repulsion. Since this could not be overcome, the idea was abandoned. But is this true? What if the rays were reversed? That is, start with a 5-m beam converging slightly with the same nonuniform angular and energy distribution as the electrons from the original problem were spreading at 1000-km distance. Could Coulomb repulsion be overcome? Looking at the terms in computational studies, some are reversible while others are not. Based on estimates, the nonreversible terms should be small - of the order of 0.1 mm. If this is true, it is possible to design a practical electron beam directed weapon not limited by Coulomb repulsion.
Gradient induced liquid motion on laser structured black Si surfaces

NASA Astrophysics Data System (ADS)

Paradisanos, I.; Fotakis, C.; Anastasiadis, S. H.; Stratakis, E.

2015-09-01

This letter reports on the femtosecond laser fabrication of gradient-wettability micro/nano-patterns on Si surfaces. The dynamics of directional droplet spreading on the surface tension gradients developed is systematically investigated and discussed. It is shown that microdroplets on the patterned surfaces spread at a maximum speed of 505 mm/s, which is the highest velocity demonstrated so far for liquid spreading on a surface tension gradient in ambient conditions. The application of the proposed laser patterning technique for the precise fabrication of surface tension gradients for open microfluidic systems, liquid management in fuel cells, and drug delivery is envisaged.
A maximum (non-extensive) entropy approach to equity options bid-ask spread

NASA Astrophysics Data System (ADS)

Tapiero, Oren J.

2013-07-01

The cross-section of options bid-ask spreads with their strikes are modelled by maximising the Kaniadakis entropy. A theoretical model results with the bid-ask spread depending explicitly on the implied volatility; the probability of expiring at-the-money and an asymmetric information parameter (κ). Considering AIG as a test case for the period between January 2006 and October 2008, we find that information flows uniquely from the trading activity in the underlying asset to its derivatives. Suggesting that κ is possibly an option implied measure of the current state of trading liquidity in the underlying asset.
Characteristics and performance of a superconducting bumpy-torus magnet facility for plasma research

NASA Technical Reports Server (NTRS)

Roth, J. R.; Holmes, A. D.; Keller, T. A.; Krawczonek, W. M.

1973-01-01

The NASA Lewis bumpy-torus facility consists of 12 superconducting coils, each 19 cm i.d. and capable of 3.0 T on its axis. The coils are equally spaced around a toroidal array with a major diameter of 1.52 m; they are mounted with the major axis of the torus vertical in a single vacuum tank 2.6 m in diameter. Tests of the facility mapped out its magnetic, cryogenic, vacuum, mechanical, and electrical performance. The design value of the maximum magnetic field on the magnetic axis, 3.0 T, was reached and exceeded. A maximum magnetic field of 3.23 T was held for a period of 60 minutes. When the coils were charged to a maximum magnetic field of 3.35 T, the coil system went normal without apparent damage or degradation of performance.
Free-Mass and Interface Configurations of Hammering Mechanisms

NASA Technical Reports Server (NTRS)

Bao, Xiaoqi; Sherrit, Stewart; Badescu, Mircea; Bar-Cohen, Yoseph; Atkins, Steve; Ostlund, Patrick N.

2012-01-01

A series of free-mass designs for the ultrasonic/ sonic driller/corer (USDC) has been developed to maximize the transfer of energy from the piezoelectric transducer through the horn to the bit, as well as to minimize potential jamming. A systematic development was made producing novel designs of free-mass configurations where the impact force is spread across a minimal area maximizing the impact on the bit. The designed free masses were made to operate at high temperatures (500 C) as on Venus, and they can be made to operate at extremely low temperature, too. In normal operation, the free mass bounces between the horn and the bit, impacting both repeatedly. The impact stress profile, maximum stress, contact time duration, and the required yielding stress for the materials of the free mass, bit, and horn are all affected by the contact area. A larger contact area results in lower stress in the contact region, and avoids yielding of the materials. However, before the excitation voltage is applied to the transducer, the horn, free mass, and the bit are pressed together. Larger contact area results in a stronger coupling of the bit to the horn transducer, which greatly changes the vibration characteristics of the transducer, and makes the USDC difficult to start. To obtain optimum performance, a catalog of free-mass designs is required, allowing maximum flexibility during trade-off for these conflicting contact area requirements. For this purpose, seven different designs were conceived: point contacts, circular contacts, point/circular contacts, line contacts, ring contacts, line/ring contacts, and dashed line contacts. Besides point/circular and line/ring contacts, the free mass can be designed as any of the above shapes. Depending on the ratio of the diameter to the height, and the free-mass retention method used (the cup or rod), the free mass can be configured with one or more sliding surfaces on the outside or inside diameter surface or both. Matching horn tips and free mass may also offer some utility in maximizing the stress pulse.
Strong focusing effect of 660 nm laser by microsized tapered glass tubes with different diameters

NASA Astrophysics Data System (ADS)

Lin, Chongnan; Luo, Xujia; Zhu, Xiaoyang; Zhu, Li; Wang, Hongcheng; Zhang, Ao; Xu, Runyu; Qu, Zheng; Chen, Ximeng; Zhang, Weiyi; Shao, Jianxiong

2017-09-01

A laser with a wavelength of 660 nm was focused by microsized tapered glass tubes with different diameters of the exit. By using the 3-μm optical fiber and micrometer displacement stages, we measured the light intensity distribution around the focal spot, the focal distance, and the transmission coefficient of the light transmitted through these tubes. The focusing effect for the glass tubes with smaller outlet diameters of the exit was found to be much stronger than those with larger diameters of the exit. Furthermore, the dependence of the size and distance and the maximum intensity of the focal spot on the tubes' diameter of exit are obtained.
Bauhinia variegata L.

Treesearch

K.F Connor

2002-01-01

Bauhinia variegata is a small to medium-sized evergreen or deciduous tree that reaches 1.8 to 7.6 m in height and up to 20.3 cm in diameter. The species grows well on soils of medium fertility that are either droughty or moist; it is not tolerate of nutrient-poor sites. Although reproduction is abundant, B. variegata spreads...
Simulated remodeling of loaded collagen networks via strain-dependent enzymatic degradation and constant-rate fiber growth

PubMed Central

Hadi, M.F.; Sander, E.A.; Ruberti, J.W.; Barocas, V. H.

2011-01-01

Recent work has demonstrated that enzymatic degradation of collagen fibers exhibits strain-dependent kinetics. Conceptualizing how the strain dependence affects remodeling of collagenous tissues is vital to our understanding of collagen management in native and bioengineered tissues. As a first step towards this goal, the current study puts forward a multiscale model for enzymatic degradation and remodeling of collagen networks for two sample geometries we routinely use in experiments as model tissues. The multiscale model, driven by microstructural data from an enzymatic decay experiment, includes an exponential strain-dependent kinetic relation for degradation and constant growth. For a dogbone sample under uniaxial load, the model predicted that the distribution of fiber diameters would spread over the course of degradation because of variation in individual fiber load. In a cross-shaped sample, the central region, which experiences smaller, more isotropic loads, showed more decay and less spread in fiber diameter compared to the arms. There was also a slight shift in average orientation in different regions of the cruciform. PMID:22180691
Rapid sealing of porcine renal blood vessels, ex vivo, using a high power, 1470-nm laser, and laparoscopic prototype

NASA Astrophysics Data System (ADS)

Hardy, Luke A.; Hutchens, Thomas C.; Larson, Eric R.; Gonzalez, David A.; Chang, Chun-Hung; Nau, William H.; Fried, Nathaniel M.

2017-05-01

Energy-based, radiofrequency (RF) and ultrasonic (US) devices currently provide rapid sealing of blood vessels during laparoscopic procedures. We are exploring infrared lasers as an alternate energy modality for vessel sealing, capable of generating less collateral thermal damage. Previous studies demonstrated feasibility of sealing vessels in an in vivo porcine model using a 1470-nm laser. However, the initial prototype was designed for testing in open surgery and featured tissue clasping and light delivery mechanisms incompatible with laparoscopic surgery. In this study, a laparoscopic prototype similar to devices currently in surgical use was developed, and performance tests were conducted on porcine renal blood vessels, ex vivo. The 5-mm outer-diameter laparoscopic prototype featured a traditional Maryland jaw configuration that enables tissue manipulation and blunt dissection. Laser energy was delivered through a 550-μm-core-diameter optical fiber with side-delivery from the lower jaw and beam dimensions of 18-mm length×1.2-mm width. The 1470-nm diode laser delivered 68 W with 3-s activation time, consistent with vessel seal times associated with RF and US-based devices. A total of 69 fresh porcine renal vessels with mean diameter of 3.3±1.7 mm were tested, ex vivo. Vessels smaller than 5-mm diameter were consistently sealed (48/51) with burst pressures greater than malignant hypertension blood pressure (180 mmHg), averaging 1038±474 mmHg. Vessels larger than 5 mm were not consistently sealed (6/18), yielding burst pressures of only 174±221 mmHg. Seal width, thermal damage zone, and thermal spread averaged 1.7±0.8, 3.4±0.7, and 1.0±0.4 mm, respectively. Results demonstrated that the 5-mm optical laparoscopic prototype consistently sealed vessels less than 5-mm diameter with low thermal spread. Further in vivo studies are planned to test the performance across a variety of vessels and tissues.

Development of a liquid tin microjet target for an efficient laser-produced plasma extreme ultraviolet source.

PubMed

Higashiguchi, Takeshi; Hamada, Masaya; Kubodera, Shoichi

2007-03-01

A regenerative tin liquid microjet target was developed for a high average power extreme ultraviolet (EUV) source. The diameter of the target was smaller than 160 microm and good vacuum lower than 0.5 Pa was maintained during the operation. A maximum EUV conversion efficiency of 1.8% at the Nd:yttrium-aluminum-garnet laser intensity of around 2 x 10(11) Wcm(2) with a spot diameter of 175 microm (full width at half maximum) was observed. The angular distribution of the EUV emission remained almost isotropic, whereas suprathermal ions mainly emerged toward the target normal.
Development of a liquid tin microjet target for an efficient laser-produced plasma extreme ultraviolet source

NASA Astrophysics Data System (ADS)

Higashiguchi, Takeshi; Hamada, Masaya; Kubodera, Shoichi

2007-03-01

A regenerative tin liquid microjet target was developed for a high average power extreme ultraviolet (EUV) source. The diameter of the target was smaller than 160 μm and good vacuum lower than 0.5 Pa was maintained during the operation. A maximum EUV conversion efficiency of 1.8% at the Nd:yttrium-aluminum-garnet laser intensity of around 2×1011 W/cm2 with a spot diameter of 175 μm (full width at half maximum) was observed. The angular distribution of the EUV emission remained almost isotropic, whereas suprathermal ions mainly emerged toward the target normal.
The provision of clearances accuracy in piston - cylinder mating

NASA Astrophysics Data System (ADS)

Glukhov, V. I.; Shalay, V. V.

2017-08-01

The paper is aimed at increasing the quality of the pumping equipment in oil and gas industry. The main purpose of the study is to stabilize maximum values of productivity and durability of the pumping equipment based on the selective assembly of the cylinder-piston kinematic mating by optimization criterion. It is shown that the minimum clearance in the piston-cylinder mating is formed by maximum material dimensions. It is proved that maximum material dimensions are characterized by their own laws of distribution within the tolerance limits for the diameters of the cylinder internal mirror and the outer cylindrical surface of the piston. At that, their dispersion zones should be divided into size groups with a group tolerance equal to half the tolerance for the minimum clearance. The techniques for measuring the material dimensions - the smallest cylinder diameter and the largest piston diameter according to the envelope condition - are developed for sorting them into size groups. Reliable control of the dimensions precision ensures optimal minimum clearances of the piston-cylinder mating in all the size groups of the pumping equipment, necessary for increasing the equipment productivity and durability during the production, operation and repair processes.
Mapping of an ultrasonic bath for ultrasound assisted extraction of mangiferin from Mangifera indica leaves.

PubMed

Kulkarni, Vrushali M; Rathod, Virendra K

2014-03-01

The present work deals with the mapping of an ultrasonic bath for the maximum extraction of mangiferin from Mangifera indica leaves. I3(-) liberation experiments (chemical transformations) and extraction (physical transformations) were carried out at different locations in an ultrasonic bath and compared. The experimental findings indicated a similar trend in variation in an ultrasonic bath by both these methods. Various parameters such as position and depth of vessel in an ultrasonic bath, diameter and shape of a vessel, frequency and input power which affect the extraction yield have been studied in detail. Maximum yield of mangiferin obtained was approximately 31 mg/g at optimized parameters: distance of 2.54 cm above the bottom of the bath, 7 cm diameter of vessel, flat bottom vessel, 6.35 cm liquid height, 122 W input power and 25 kHz frequency. The present work indicates that the position and depth of vessel in an ultrasonic bath, diameter and shape of a vessel, frequency and input power have significant effect on the extraction yield. This work can be used as a base for all ultrasonic baths to obtain maximum efficiency for ultrasound assisted extraction. Copyright © 2013 Elsevier B.V. All rights reserved.
Impact dynamics of oxidized liquid metal drops

NASA Astrophysics Data System (ADS)

Xu, Qin; Brown, Eric; Jaeger, Heinrich M.

2013-04-01

With exposure to air, many liquid metals spontaneously generate an oxide layer on their surface. In oscillatory rheological tests, this skin is found to introduce a yield stress that typically dominates the elastic response but can be tuned by exposing the metal to hydrochloric acid solutions of different concentration. We systematically studied the normal impact of eutectic gallium-indium (eGaIn) drops under different oxidation conditions and show how this leads to two different dynamical regimes. At low impact velocity (or low Weber number), eGaIn droplets display strong recoil and rebound from the impacted surface when the oxide layer is removed. In addition, the degree of drop deformation or spreading during impact is controlled by the oxide skin. We show that the scaling law known from ordinary liquids for the maximum spreading radius as a function of impact velocity can still be applied to the case of oxidized eGaIn if an effective Weber number We is employed that uses an effective surface tension factoring in the yield stress. In contrast, no influence on spreading from different oxidations conditions is observed for high impact velocity. This suggests that the initial kinetic energy is mostly damped by bulk viscous dissipation. Results from both regimes can be collapsed in an impact phase diagram controlled by two variables, the maximum spreading factor Pm=R0/Rm, given by the ratio of initial to maximum drop radius, and the impact number K=We/Re4/5, which scales with the effective Weber number We as well as the Reynolds number Re. The data exhibit a transition from capillary to viscous behavior at a critical impact number Kc≈0.1.
Impact dynamics of oxidized liquid metal drops.

PubMed

Xu, Qin; Brown, Eric; Jaeger, Heinrich M

2013-04-01

With exposure to air, many liquid metals spontaneously generate an oxide layer on their surface. In oscillatory rheological tests, this skin is found to introduce a yield stress that typically dominates the elastic response but can be tuned by exposing the metal to hydrochloric acid solutions of different concentration. We systematically studied the normal impact of eutectic gallium-indium (eGaIn) drops under different oxidation conditions and show how this leads to two different dynamical regimes. At low impact velocity (or low Weber number), eGaIn droplets display strong recoil and rebound from the impacted surface when the oxide layer is removed. In addition, the degree of drop deformation or spreading during impact is controlled by the oxide skin. We show that the scaling law known from ordinary liquids for the maximum spreading radius as a function of impact velocity can still be applied to the case of oxidized eGaIn if an effective Weber number We* is employed that uses an effective surface tension factoring in the yield stress. In contrast, no influence on spreading from different oxidations conditions is observed for high impact velocity. This suggests that the initial kinetic energy is mostly damped by bulk viscous dissipation. Results from both regimes can be collapsed in an impact phase diagram controlled by two variables, the maximum spreading factor P(m)=R(0)/R(m), given by the ratio of initial to maximum drop radius, and the impact number K=We*/Re(4/5), which scales with the effective Weber number We* as well as the Reynolds number Re. The data exhibit a transition from capillary to viscous behavior at a critical impact number K(c)≈0.1.
Thermal Effect of J-Plasma® Energy in a Porcine Tissue Model: Implications for Minimally Invasive Surgery.

PubMed

Pedroso, Jasmine D; Gutierrez, Melissa M; Volker, K Warren; Howard, David L

2017-07-25

To evaluate tissue effect of J-Plasma® (Bovie Medical Corporation, Clearwater, Florida) in porcine liver, kidney, muscle, ovarian, and uterine tissue blocks. Prospective study utilizing porcine tissue blocks to evaluate the thermal spread of J-Plasma® device on liver, kidney, muscle, ovarian, and uterine tissue at various power settings, gas flow, and exposure times. J-Plasma® helium was used in porcine liver, kidney, and muscle tissue at 20%, 50%, and 100% power, and 1 L/min, 3 L/min, and 5 L/min gas flow at one, five, and 10-second intervals. J-Plasma® was then used in ovarian and uterine tissue at maximum power and gas flow settings in intervals of one, five, 10, and 30 seconds. Histologic evaluation of each tissue was then performed to measure thermal spread. Regardless of tissue type, increased power setting, gas flow rate, and exposure time correlated with greater depth of thermal spread in liver, kidney, and muscle tissue. J-Plasma® did not exceed 2 mm thermal spread on liver, kidney, muscle, ovarian, and uterine tissue, even at a maximum setting of 100% power and 5 L/min gas flow after five seconds. Prolonged exposure to J-Plasma® of up to 30 seconds resulted in increased length and width of thermal spread of up to 12 mm, but did not result in significantly increased depth at 2.84 mm. The J-Plasma® helium device has minimal lateral and depth of thermal spread in a variety of tissue types and can likely be used for a multitude of gynecologic surgical procedures. However, further studies are needed to demonstrate device safety in a clinical setting.
Dominance of layer-specific microvessel dilation in contrast-enhanced high-resolution fMRI: Comparison between hemodynamic spread and vascular architecture with CLARITY.

PubMed

Poplawsky, Alexander John; Fukuda, Mitsuhiro; Kang, Bok-Man; Kim, Jae Hwan; Suh, Minah; Kim, Seong-Gi

2017-08-16

Contrast-enhanced cerebral blood volume-weighted (CBVw) fMRI response peaks are specific to the layer of evoked synaptic activity (Poplawsky et al., 2015), but the spatial resolution limit of CBVw fMRI is unknown. In this study, we measured the laminar spread of the CBVw fMRI evoked response in the external plexiform layer (EPL, 265 ± 65 μm anatomical thickness, mean ± SD, n = 30 locations from 5 rats) of the rat olfactory bulb during electrical stimulation of the lateral olfactory tract and examined its potential vascular source. First, we obtained the evoked CBVw fMRI responses with a 55 × 55 μm 2 in-plane resolution and a 500-μm thickness at 9.4 T, and found that the fMRI signal peaked predominantly in the inner half of EPL (136 ± 54 μm anatomical thickness). The mean full-width at half-maximum of these fMRI peaks was 347 ± 102 μm and the functional spread was approximately 100 or 200 μm when the effects of the laminar thicknesses of EPL or inner EPL were removed, respectively. Second, we visualized the vascular architecture of EPL from a different rat using a Clear Lipid-exchanged Anatomically Rigid Imaging/immunostaining-compatible Tissue hYdrogel (CLARITY)-based tissue preparation method and confocal microscopy. Microvascular segments with an outer diameter of <11 μm accounted for 64.3% of the total vascular volume within EPL and had a mean segment length of 55 ± 40 μm (n = 472). Additionally, vessels that crossed the EPL border had a mean segment length outside of EPL equal to 73 ± 61 μm (n = 28), which is comparable to half of the functional spread (50-100 μm). Therefore, we conclude that dilation of these microvessels, including capillaries, likely dominate the CBVw fMRI response and that the biological limit of the fMRI spatial resolution is approximately the average length of 1-2 microvessel segments, which may be sufficient for examining sublaminar circuits. Copyright © 2017 Elsevier Inc. All rights reserved.
Nanodroplets Impact on Rough Surfaces: A Simulation and Theoretical Study.

PubMed

Gao, Shan; Liao, Quanwen; Liu, Wei; Liu, Zhichun

2018-05-22

Impact of droplets is widespread in life, and modulating the dynamics of impinging droplets is a significant problem in production. However, on textured surfaces, the micromorphologic change and mechanism of impinging nanodroplets are not well-understood; furthermore, the accuracy of the theoretical model for nanodroplets needs to be improved. Here, considering the great challenge of conducting experiments on nanodroplets, a molecular dynamics simulation is performed to visualize the impact process of nanodroplets on nanopillar surfaces. Compared with macroscale droplets, apart from the similar relation of restitution coefficient with the Weber number, we found some distinctive results: the maximum spreading time is described as a power law of impact velocity, and the relation of maximum spreading factor with impact velocity or the Reynolds number is exponential. Moreover, the roughness of substrates plays a prominent role in the dynamics of impact nanodroplets, and on surfaces with lower solid fraction, the lower attraction force induces an easier rebound of impact nanodroplets. At last, on the basis of the energy balance, through modifying the estimation of viscous dissipation and surface energy terms, we proposed an improved model for the maximum spreading factor, which shows greater accuracy for nanodroplets, especially in the low-to-moderate velocity range. The outcome of this study demonstrates that a distinctive dynamical behavior of impinging nanodroplets, the fundamental insight, and more accurate prediction are very useful in the improvement of the hydrodynamic behavior of the nanodroplets.
Performance Assessment of a Large Scale Pulsejet- Driven Ejector System

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.; Litke, Paul J.; Schauer, Frederick R.; Bradley, Royce P.; Hoke, John L.

2006-01-01

Unsteady thrust augmentation was measured on a large scale driver/ejector system. A 72 in. long, 6.5 in. diameter, 100 lb(sub f) pulsejet was tested with a series of straight, cylindrical ejectors of varying length, and diameter. A tapered ejector configuration of varying length was also tested. The objectives of the testing were to determine the dimensions of the ejectors which maximize thrust augmentation, and to compare the dimensions and augmentation levels so obtained with those of other, similarly maximized, but smaller scale systems on which much of the recent unsteady ejector thrust augmentation studies have been performed. An augmentation level of 1.71 was achieved with the cylindrical ejector configuration and 1.81 with the tapered ejector configuration. These levels are consistent with, but slightly lower than the highest levels achieved with the smaller systems. The ejector diameter yielding maximum augmentation was 2.46 times the diameter of the pulsejet. This ratio closely matches those of the small scale experiments. For the straight ejector, the length yielding maximum augmentation was 10 times the diameter of the pulsejet. This was also nearly the same as the small scale experiments. Testing procedures are described, as are the parametric variations in ejector geometry. Results are discussed in terms of their implications for general scaling of pulsed thrust ejector systems
Pyrolysis of Large Black Liquor Droplets

NASA Technical Reports Server (NTRS)

Bartkus, Tadas P.; Dietrich, Daniel L.; T'ien, James S.; Wessel, Richard A.

2007-01-01

This paper presents the results of experiments involving the pyrolysis of large black liquor droplets in the NASA KC-135 reduced gravity aircraft. The reduced gravity environment facilitated the study of droplets up to 9 mm in diameter extending the results of previous studies to droplet sizes that are similar to those encountered in recovery boilers. Single black liquor droplets were rapidly inserted into a 923 K oven. The primary independent variables were the initial droplet diameter (0.5 mm to 9 mm), the black liquor solids content (66.12% - 72.9% by mass), and the ambient oxygen mole fraction (0.0 - 0.21). Video records of the experiments provided size and shape of the droplets as a function of time. The results show that the particle diameter at the end of the drying stage (D(sub DRY)) increases linearly with the initial particle diameter (D(sub O)). The results further show that the ratio of the maximum swollen diameter (D(sub MAX)) to D(sub O) decreases with increasing D(sub O) for droplets with D(sub O) less than 4 mm. This ratio was independent of D(sub O) for droplets with D(sub O) greater than 4 mm. The particle is most spherical at the end of drying, and least spherical at maximum swollen size, regardless of initial sphericity and droplet size.
Pyrolysis of Large Black Liquor Droplets

NASA Technical Reports Server (NTRS)

Bartkus, Tadas P.; T'ien, James S.; Dietrich, Daniel L.; Wessel, Richard A.

2007-01-01

This paper presents the results of experiments involving the pyrolysis of large black liquor droplets in the NASA KC-135 reduced gravity aircraft. The reduced gravity environment facilitated the study of droplets up to 9 mm in diameter extending the results of previous studies to droplet sizes that are similar to those encountered in recovery boilers. Single black liquor droplets were rapidly inserted into a 923 K oven. The primary independent variables were the initial droplet diameter (0.5 mm to 9 mm), the black liquor solids content (66.12% - 72.9% by mass), and the ambient oxygen mole fraction (0.0 - 0.21). Video records of the experiments provided size and shape of the droplets as a function of time. The results show that the particle diameter at the end of the drying stage (D(sub DRY) ) increases linearly with the initial particle diameter (D(sub O)). The results further show that the ratio of the maximum swollen diameter (D(sub MAX)) to D(sub O) decreases with increasing D(sub O) for droplets with D(sub O) less than 4 mm. This ratio was independent of D(sub O) for droplets with D(sub O) greater than 4 mm. The particle is most spherical at the end of drying, and least spherical at maximum swollen size, regardless of initial sphericity and droplet size.
Effects of a monophasic combined oral contraceptive containing nomegestrol acetate and 17 beta-oestradiol on ovarian function in comparison to a monophasic combined oral contraceptive containing drospirenone and ethinylestradiol.

PubMed

Duijkers, Ingrid J M; Klipping, Christine; Grob, Paul; Korver, Tjeerd

2010-10-01

To compare the effects on ovarian activity of two oral contraceptives containing nomegestrol acetate (NOMAC)/17 beta-oestradiol (E2) or drospirenone (DRSP)/ethinylestradiol (EE). In this open-label, randomised, six-cycle study, 32 subjects using NOMAC/E2 (2.5-1.5 mg; 24/4-day regimen) were compared to 16 subjects using DRSP/EE (3 mg-30 microg; 21/7-day regimen). Measurements included serum oestradiol, progesterone, follicle stimulating hormone (FSH) and luteinising hormone (LH), and ultrasonography of follicular diameter. No ovulations occurred during treatment. Progesterone was fully suppressed, with mean maximum values <2 nmol/l in both groups over all cycles. For NOMAC/E2, mean maximum follicular diameter decreased from 19.3 mm before treatment to between 6.9 and 8.2 mm during treatment, with no subject having a follicular diameter ≥15 mm. For DRSP/EE, a decrease from 19.6 to between 7.4 and 10.8 mm was observed, with two subjects (12.5%) having a maximum follicle diameter ≥15 mm. These findings were consistent with observed FSH reductions; full suppression of LH surges was observed in both groups. Post-treatment return of ovulation in both groups occurred on average 21 days after the last active tablet intake. NOMAC/E2 achieves consistent ovulation inhibition, with suppressive effects on the ovaries at least similar to those of DRSP/EE.
Effect of drop size on the impact thermodynamics for supercooled large droplet in aircraft icing

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

Zhang, Chen; Liu, Hong, E-mail: hongliu@sjtu.edu.cn

Supercooled large droplet (SLD), which can cause abnormal icing, is a well-known issue in aerospace engineering. Although efforts have been exerted to understand large droplet impact dynamics and the supercooled feature in the film/substrate interface, respectively, the thermodynamic effect during the SLD impact process has not received sufficient attention. This work conducts experimental studies to determine the effects of drop size on the thermodynamics for supercooled large droplet impingement. Through phenomenological reproduction, the rapid-freezing characteristics are observed in diameters of 400, 800, and 1300 μm. The experimental analysis provides information on the maximum spreading rate and the shrinkage rate ofmore » the drop, the supercooled diffusive rate, and the freezing time. A physical explanation of this unsteady heat transfer process is proposed theoretically, which indicates that the drop size is a critical factor influencing the supercooled heat exchange and effective heat transfer duration between the film/substrate interface. On the basis of the present experimental data and theoretical analysis, an impinging heating model is developed and applied to typical SLD cases. The model behaves as anticipated, which underlines the wide applicability to SLD icing problems in related fields.« less
40 CFR 204.55-3 - Configuration identification.

Code of Federal Regulations, 2011 CFR

2011-07-01

... compressor stages. (3) Maximum pressure (psi). (4) Air intake system of compressor: (i) Number of filters; (ii) Type of filters. (5) The engine system: (i) Number of cylinders and configuration (L-6, V-8, V-12..., water cooled. (7) Fan: (i) Diameter; (ii) Maximum fan rpm. (8) The compressor enclosure: (i) Height...
40 CFR 204.55-3 - Configuration identification.

Code of Federal Regulations, 2013 CFR

2013-07-01

... compressor stages. (3) Maximum pressure (psi). (4) Air intake system of compressor: (i) Number of filters; (ii) Type of filters. (5) The engine system: (i) Number of cylinders and configuration (L-6, V-8, V-12..., water cooled. (7) Fan: (i) Diameter; (ii) Maximum fan rpm. (8) The compressor enclosure: (i) Height...
40 CFR 204.55-3 - Configuration identification.

Code of Federal Regulations, 2014 CFR

2014-07-01

... compressor stages. (3) Maximum pressure (psi). (4) Air intake system of compressor: (i) Number of filters; (ii) Type of filters. (5) The engine system: (i) Number of cylinders and configuration (L-6, V-8, V-12..., water cooled. (7) Fan: (i) Diameter; (ii) Maximum fan rpm. (8) The compressor enclosure: (i) Height...
40 CFR 204.55-3 - Configuration identification.

Code of Federal Regulations, 2012 CFR

2012-07-01

... compressor stages. (3) Maximum pressure (psi). (4) Air intake system of compressor: (i) Number of filters; (ii) Type of filters. (5) The engine system: (i) Number of cylinders and configuration (L-6, V-8, V-12..., water cooled. (7) Fan: (i) Diameter; (ii) Maximum fan rpm. (8) The compressor enclosure: (i) Height...
Automatic detection of cardiac cycle and measurement of the mitral annulus diameter in 4D TEE images

NASA Astrophysics Data System (ADS)

Graser, Bastian; Hien, Maximilian; Rauch, Helmut; Meinzer, Hans-Peter; Heimann, Tobias

2012-02-01

Mitral regurgitation is a wide spread problem. For successful surgical treatment quantification of the mitral annulus, especially its diameter, is essential. Time resolved 3D transesophageal echocardiography (TEE) is suitable for this task. Yet, manual measurement in four dimensions is extremely time consuming, which confirms the need for automatic quantification methods. The method we propose is capable of automatically detecting the cardiac cycle (systole or diastole) for each time step and measuring the mitral annulus diameter. This is done using total variation noise filtering, the graph cut segmentation algorithm and morphological operators. An evaluation took place using expert measurements on 4D TEE data of 13 patients. The cardiac cycle was detected correctly on 78% of all images and the mitral annulus diameter was measured with an average error of 3.08 mm. Its full automatic processing makes the method easy to use in the clinical workflow and it provides the surgeon with helpful information.
Verification and Validation of the Coastal Modeling System. Report 3: CMS-Flow: Hydrodynamics

DTIC Science & Technology

2011-12-01

Jansen (1978) Spectrum TMA Directional spreading distribution Cosine Power Directional spreading parameter γ 3.3 Bottom friction Off (default...Ramp duration 3 hr The wave breaking formula applied was Battjes and Jansen (1978) because it is the recommended wave breaking formula when using...Li, Z.H., K.D. Nguyen , J.C. Brun-Cottan and J.M. Martin. 1994. Numerical simulation of the turbidity maximum transport in the Gironde Estuary (France

Contact angle measurements of a polyphenyl ether to 190 C on M-50 steel

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.

1981-01-01

Contact angle measurements were performed for a polyphenyl ether on steel in nitrogen. A tilting plate and a sessile drop apparatus were used. Surface tension was measured with a maximum bubble pressure apparatus. Critical surface energies of spreading were found to be 30.1 and 31.3 dynes/cm. It was concluded that the polyphenyl ether is inherently autophobic and will not spread on its own surface film.
A comparison of hydraulic architecture in three similarly sized woody species differing in their maximum potential height.

PubMed

McCulloh, Katherine A; Johnson, Daniel M; Petitmermet, Joshua; McNellis, Brandon; Meinzer, Frederick C; Lachenbruch, Barbara

2015-07-01

The physiological mechanisms underlying the short maximum height of shrubs are not understood. One possible explanation is that differences in the hydraulic architecture of shrubs compared with co-occurring taller trees prevent the shrubs from growing taller. To explore this hypothesis, we examined various hydraulic parameters, including vessel lumen diameter, hydraulic conductivity and vulnerability to drought-induced embolism, of three co-occurring species that differed in their maximum potential height. We examined one species of shrub, one short-statured tree and one taller tree. We worked with individuals that were approximately the same age and height, which was near the maximum for the shrub species. A number of variables correlated with the maximum potential height of the species. For example, vessel diameter and vulnerability to embolism both increased while wood density declined with maximum potential height. The difference between the pressure causing 50% reduction in hydraulic conductance in the leaves and the midday leaf water potential (the leaf's hydraulic safety margin) was much larger in the shrub than the other two species. In general, trends were consistent with understory shrubs having a more conservative life history strategy than co-occurring taller species. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Eco-friendly Fibre from Recycled Polypropylene of Bottle Cap Waste and Lignin

NASA Astrophysics Data System (ADS)

Soekoco, A. S.; Basuki, A.; Mardiyati

2016-01-01

Ecofriendly fibre is one of potential alternatives to fulfill the rising demand in textile material supply which is limited due to the decreasing reserve of oil. Large amount of polypropylene waste from bottle cap and lignin as a byproduct from pulp industry are potential solutions. Grinded polypropylene bottle cap was blended with lignin powder in concentration of 5 wt. % processed by melt spinning at 170° C temperature. The fibres produced have an average diameter 170 and 250 micrometres. In view of the mechanical properties. the tensile strength is 11.9 MPa for fibre with 170 micrometres diameter and 14.7 MPa for fibre with 250 micrometres diameter. Fibre surface morphology was further studied using micron microscope. and the result shows black flocks spread in the fibre. indicating that the lignin does not blend evenly.
Rewetting of hot vertical rod during jet impingement surface cooling

NASA Astrophysics Data System (ADS)

Agrawal, Chitranjan; Kumar, Ravi; Gupta, Akhilesh; Chatterjee, Barun

2016-06-01

A stainless steel (SS-316) vertical rod of 12 mm diameter at 800 ± 10 °C initial temperature was cooled by normal impinging round water jet. The surface rewetting phenomenon was investigated for a range of jet diameter 2.5-4.8 mm and jet Reynolds number 5000-24,000 using a straight tube type nozzle. The investigation were made from the stagnation point to maximum 40 mm downstream locations, simultaneously for both upside and downside directions. The cooling performance of the vertical rod was evaluated on the basis of rewetting parameters i.e. rewetting temperature, wetting delay, rewetting velocity and the maximum surface heat flux. Two separate Correlations have been proposed for the dimensionless rewetting velocity in terms of rewetting number and the maximum surface heat flux that predicts the experimental data within an error band of ±20 and ±15 % respectively.
Investigation of artificial recharge of aquifers in Nebraska

USGS Publications Warehouse

Lichtler, William F.; Stannard, David I.; Kouma, Edwin

1980-01-01

Progressive declines of ground-water levels in some areas of Nebraska prompted this investigation into the technical feasibility of recharging aquifers through wells, impoundments, pits, and canals. Information gained from a literature search and from preliminary tests was used to design several artificial-recharge experiments in Nebraska from 1977 to 1979. In well experiments, 0.46 billion gallons of water from an aquifer recharged by the Platte River was transported by pipeline and injected through a well into a sand and gravel aquifer near Aurora. Recharge was at about 730 gallons per minute during tests of 6- and 8-months duration. No evidence of clogging of the aquifer due to chemical reactions, air entrainment, or bacteria was detected in either test. In the 6-month test, evidence of clogging due to fine sediment in the recharge water was detected; however, analysis of this test indicated that recharge could have continued for several years before rehabilitation would have become necessary. Results of the 8-month test confirmed results of the earlier test until casing failure in the supply well and subsequent sediment deposition in the recharge well caused rapid water-level rise in the recharge well. In surface-spreading experiments, maximum infiltration rates from 24-foot-diameter ring infiltrometers near Aurora and Tryon were 0.4 and 11 feet per day, respectively. Results indicate that large-scale surface spreading is feasible only where low-permeability layers are absent in the subsurface. Infiltration rates from reuse pits ranged from 0.01 to 1.6 feet per day, indicating highly variable subsurface permeability. Flow measurements in an irrigation canal near Farwell indicate an infiltration rate of 0.37 feet per day. (USGS)
Evaluation of the technical performance of three different commercial digital breast tomosynthesis systems in the clinical environment.

PubMed

Rodríguez-Ruiz, A; Castillo, M; Garayoa, J; Chevalier, M

2016-06-01

The aim of this work was to research and evaluate the performance of three different digital breast tomosynthesis (DBT) systems in the clinical environment (Siemens Mammomat Inspiration, Hologic Selenia Dimensions, and Fujifilm Amulet Innovality). The characterization included the study of the detector, the automatic exposure control, and the resolution of DBT projections and reconstructed planes. The modulation transfer function (MTF) of the DBT projections was measured with a 1mm thick steel edge, showing a strong anisotropy (30-40% lower MTF0.5 frequencies in the tube travel direction). The in-plane MTF0.5, measured with a 25μm tungsten wire, ranges from 1.3 to 1.8lp/mm in the tube-travel direction and between 2.4 and 3.7lp/mm in the chest wall-nipple. In the latter direction, the MTF peak shift is more emphasized for large angular range systems (2.0 versus 1.0lp/mm). In-depth resolution of the planes, via the full width at half maximum (FWHM) from the point spread function of a 25μm tungsten wire, is not only influenced by angular range and yields 1.3-4.6mm among systems. The artifact spread function from 1mm diameter tungsten beads depends mainly on angular range, yielding two tendencies whether large (FWHM is 4.5mm) or small (FWHM is 10mm) angular range is used. DBT delivers per scan a mean glandular dose between 1.4 and 2.7mGy for a 45mm thick polymethyl methacrylate (PMMA) block. In conclusion, we have identified and analysed specific metrics that can be used for quality assurance of DBT systems. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
Micropatterning tractional forces in living cells

NASA Technical Reports Server (NTRS)

Wang, Ning; Ostuni, Emanuele; Whitesides, George M.; Ingber, Donald E.

2002-01-01

Here we describe a method for quantifying traction in cells that are physically constrained within micron-sized adhesive islands of defined shape and size on the surface of flexible polyacrylamide gels that contain fluorescent microbeads (0.2-microm diameter). Smooth muscle cells were plated onto square (50 x 50 microm) or circular (25- or 50-microm diameter) adhesive islands that were created on the surface of the gels by applying a collagen coating through microengineered holes in an elastomeric membrane that was later removed. Adherent cells spread to take on the size and shape of the islands and cell tractions were quantitated by mapping displacement fields of the fluorescent microbeads within the gel. Cells on round islands did not exhibit any preferential direction of force application, but they exerted their strongest traction at sites where they formed protrusions. When cells were confined to squares, traction was highest in the corners both in the absence and presence of the contractile agonist, histamine, and cell protrusions were also observed in these regions. Quantitation of the mean traction exerted by cells cultured on the different islands revealed that cell tension increased as cell spreading was promoted. These results provide a mechanical basis for past studies that demonstrated a similar correlation between spreading and growth within various anchorage-dependent cells. This new approach for analyzing the spatial distribution of mechanical forces beneath individual cells that are experimentally constrained to defined sizes and shapes may provide additional insight into the biophysical basis of cell regulation. Copyright 2002 Wiley-Liss, Inc.
Superconducting cable connections and methods

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

van der Laan, Daniel Cornelis

2017-09-05

Superconducting cable connector structures include a terminal body (or other structure) onto which the tapes from the superconducting cable extend. The terminal body (or other structure) has a diameter that is sufficiently larger than the diameter of the former of the superconducting cable, so that the tapes spread out over the outer surface of the terminal body. As a result, gaps are formed between tapes on the terminal body (or other structure). Those gaps are filled with solder (or other suitable flowable conductive material), to provide a current path of relatively high conductivity in the radial direction. Other connector structuresmore » omit the terminal body.« less
Mechanical coupling limits the density and quality of self-organized carbon nanotube growth

NASA Astrophysics Data System (ADS)

Bedewy, Mostafa; Hart, A. John

2013-03-01

Aligned carbon nanotube (CNT) structures are promising for many applications; however, as-grown CNT "forests" synthesized by chemical vapor deposition (CVD) are typically low-density and mostly comprise tortuous defective CNTs. Here, we present evidence that the density and alignment of self-organized CNT growth is limited by mechanical coupling among CNTs in contact, in combination with their diameter-dependent growth rates. This study is enabled by comprehensive X-ray characterization of the spatially and temporally-varying internal morphology of CNT forests. Based on this data, we model the time evolution and diameter-dependent scaling of the ensuing mechanical forces on catalyst nanoparticles during CNT growth, which arise from the mismatch between the collective lengthening rate of the forest and the diameter-dependent growth rates of individual CNTs. In addition to enabling self-organization of CNTs into forests, time-varying forces between CNTs in contact dictate the hierarchical tortuous morphology of CNT forests, and may be sufficient to influence the structural quality of CNTs. These forces reach a maximum that is coincident with the maximum density observed in our growth process, and are proportional to CNT diameter. Therefore, we propose that improved manufacturing strategies for self-organized CNTs should consider both chemical and mechanical effects. This may be especially necessary to achieve high density CNT forests with low defect density, such as for improved thermal interfaces and high-permeability membranes.Aligned carbon nanotube (CNT) structures are promising for many applications; however, as-grown CNT "forests" synthesized by chemical vapor deposition (CVD) are typically low-density and mostly comprise tortuous defective CNTs. Here, we present evidence that the density and alignment of self-organized CNT growth is limited by mechanical coupling among CNTs in contact, in combination with their diameter-dependent growth rates. This study is enabled by comprehensive X-ray characterization of the spatially and temporally-varying internal morphology of CNT forests. Based on this data, we model the time evolution and diameter-dependent scaling of the ensuing mechanical forces on catalyst nanoparticles during CNT growth, which arise from the mismatch between the collective lengthening rate of the forest and the diameter-dependent growth rates of individual CNTs. In addition to enabling self-organization of CNTs into forests, time-varying forces between CNTs in contact dictate the hierarchical tortuous morphology of CNT forests, and may be sufficient to influence the structural quality of CNTs. These forces reach a maximum that is coincident with the maximum density observed in our growth process, and are proportional to CNT diameter. Therefore, we propose that improved manufacturing strategies for self-organized CNTs should consider both chemical and mechanical effects. This may be especially necessary to achieve high density CNT forests with low defect density, such as for improved thermal interfaces and high-permeability membranes. Electronic supplementary information (ESI) available: Detailed description of the cold-wall CVD reactor used for growing CNTs; fitting the diameter-dependent model-predicted CNT growth kinetics; time evolution of compressive stresses as a function of CNT diameter; time evolution of the diameter dependent variations in CNT number density; cumulative forest mass kinetics normalized to the number of CNTs. See DOI: 10.1039/c3nr34067h
Precision Experiments with Ultraslow Muons

NASA Astrophysics Data System (ADS)

Mills, Allen P.

A source of ~105 ultraslow muons (USM) per second (~0.2 eV energy spread and 40 mm source diameter) reported by Miyake et al., and the demonstration of 100 K thermal muonium in vacuum by Antognini, et al., suggest possibilities for substantial improvements in the experimental precisions of the muonium 1S-2S interval and the muon g-2 measurements.
Effect of surfactant concentration on the spreading properties of pesticide droplets on Eucalyptus leaves

USDA-ARS?s Scientific Manuscript database

The area wetted by 500-µm diameter droplets of pesticide and deionised water placed at different positions on Eucalyptus urophylla × E. grandis (E.u × E.g) and Eucalyptus tereticornis (E.t) leaves was determined at an air temperature of 30 °C and a relative humidity of 60%. Dimethyl dichlorovinyl ph...
Effects of electric field on the maximum electro-spinning rate of silk fibroin solutions.

PubMed

Park, Bo Kyung; Um, In Chul

2017-02-01

Owing to the excellent cyto-compatibility of silk fibroin (SF) and the simple fabrication of nano-fibrous webs, electro-spun SF webs have attracted much research attention in numerous biomedical fields. Because the production rate of electro-spun webs is strongly dependent on the electro-spinning rate used, the electro-spinning rate becomes more important. In the present study, to improve the electro-spinning rate of SF solutions, various electric fields were applied during electro-spinning of SF, and its effects on the maximum electro-spinning rate of SF solution as well as diameters and molecular conformations of the electro-spun SF fibers were examined. As the electric field was increased, the maximum electro-spinning rate of the SF solution also increased. The maximum electro-spinning rate of a 13% SF solution could be increased 12×by increasing the electric field from 0.5kV/cm (0.25mL/h) to 2.5kV/cm (3.0mL/h). The dependence of the fiber diameter on the present electric field was not significant when using less-concentrated SF solutions (7-9% SF). On the other hand, at higher SF concentrations the electric field had a greater effect on the resulting fiber diameter. The electric field had a minimal effect of the molecular conformation and crystallinity index of the electro-spun SF webs. Copyright © 2016 Elsevier B.V. All rights reserved.
Simulations of a micro-PET system based on liquid xenon

NASA Astrophysics Data System (ADS)

Miceli, A.; Glister, J.; Andreyev, A.; Bryman, D.; Kurchaninov, L.; Lu, P.; Muennich, A.; Retiere, F.; Sossi, V.

2012-03-01

The imaging performance of a high-resolution preclinical micro-positron emission tomography (micro-PET) system employing liquid xenon (LXe) as the gamma-ray detection medium was simulated. The arrangement comprises a ring of detectors consisting of trapezoidal LXe time projection ionization chambers and two arrays of large area avalanche photodiodes for the measurement of ionization charge and scintillation light. A key feature of the LXePET system is the ability to identify individual photon interactions with high energy resolution and high spatial resolution in three dimensions and determine the correct interaction sequence using Compton reconstruction algorithms. The simulated LXePET imaging performance was evaluated by computing the noise equivalent count rate, the sensitivity and point spread function for a point source according to the NEMA-NU4 standard. The image quality was studied with a micro-Derenzo phantom. Results of these simulation studies included noise equivalent count rate peaking at 1326 kcps at 188 MBq (705 kcps at 184 MBq) for an energy window of 450-600 keV and a coincidence window of 1 ns for mouse (rat) phantoms. The absolute sensitivity at the center of the field of view was 12.6%. Radial, tangential and axial resolutions of 22Na point sources reconstructed with a list-mode maximum likelihood expectation maximization algorithm were ⩽0.8 mm (full-width at half-maximum) throughout the field of view. Hot-rod inserts of <0.8 mm diameter were resolvable in the transaxial image of a micro-Derenzo phantom. The simulations show that a LXe system would provide new capabilities for significantly enhancing PET images.
Intradural Procedural Time to Assess Technical Difficulty of Superciliary Keyhole and Pterional Approaches for Unruptured Middle Cerebral Artery Aneurysms

PubMed Central

Choi, Yeon-Ju; Son, Wonsoo; Park, Ki-Su

2016-01-01

Objective This study used the intradural procedural time to assess the overall technical difficulty involved in surgically clipping an unruptured middle cerebral artery (MCA) aneurysm via a pterional or superciliary approach. The clinical and radiological variables affecting the intradural procedural time were investigated, and the intradural procedural time compared between a superciliary keyhole approach and a pterional approach. Methods During a 5.5-year period, patients with a single MCA aneurysm were enrolled in this retrospective study. The selection criteria for a superciliary keyhole approach included : 1) maximum diameter of the unruptured MCA aneurysm <15 mm, 2) neck diameter of the MCA aneurysm <10 mm, and 3) aneurysm location involving the sphenoidal or horizontal segment of MCA (M1) segment and MCA bifurcation, excluding aneurysms distal to the MCA genu. Meanwhile, the control comparison group included patients with the same selection criteria as for a superciliary approach, yet who preferred a pterional approach to avoid a postoperative facial wound or due to preoperative skin trouble in the supraorbital area. To determine the variables affecting the intradural procedural time, a multiple regression analysis was performed using such data as the patient age and gender, maximum aneurysm diameter, aneurysm neck diameter, and length of the pre-aneurysm M1 segment. In addition, the intradural procedural times were compared between the superciliary and pterional patient groups, along with the other variables. Results A total of 160 patients underwent a superciliary (n=124) or pterional (n=36) approach for an unruptured MCA aneurysm. In the multiple regression analysis, an increase in the diameter of the aneurysm neck (p<0.001) was identified as a statistically significant factor increasing the intradural procedural time. A Pearson correlation analysis also showed a positive correlation (r=0.340) between the neck diameter and the intradural procedural time. When comparing the superciliary and pterional groups, no statistically significant between-group difference was found in terms of the intradural procedural time reflecting the technical difficulty (mean±standard deviation : 29.8±13.0 min versus 27.7±9.6 min). Conclusion A superciliary keyhole approach can be a useful alternative to a pterional approach for an unruptured MCA aneurysm with a maximum diameter <15 mm and neck diameter <10 mm, representing no more of a technical challenge. For both surgical approaches, the technical difficulty increases along with the neck diameter of the MCA aneurysm. PMID:27847568
Experimental and numerical investigations of the impingement of an oblique liquid jet onto a superhydrophobic surface: energy transformation

NASA Astrophysics Data System (ADS)

Kibar, Ali

2016-02-01

This study presents the theory of impinging an oblique liquid jet onto a vertical superhydrophobic surface based on both experimental and numerical results. A Brassica oleracea leaf with a 160° apparent contact angle was used for the superhydrophobic surface. Distilled water was sent onto the vertical superhydrophobic surface in the range of 1750-3050 Reynolds number, with an inclination angle of 20°-40°, using a circular glass tube with a 1.75 mm inner diameter. The impinging liquid jet spread onto the surface governed by the inertia of the liquid and then reflected off the superhydrophobic surface due to the surface energy of the spreading liquid. Two different energy approaches, which have time-scale and per-unit length, were performed to determine transformation of the energy. The kinetic energy of the impinging liquid jet was transformed into the surface energy with an increasing interfacial surface area between the liquid and air during spreading. Afterwards, this surface energy of the spreading liquid was transformed into the reflection kinetic energy.
Inter-comparison of three-dimensional models of volcanic plumes

USGS Publications Warehouse

Suzuki, Yujiro; Costa, Antonio; Cerminara, Matteo; Esposti Ongaro, Tomaso; Herzog, Michael; Van Eaton, Alexa; Denby, Leif

2016-01-01

We performed an inter-comparison study of three-dimensional models of volcanic plumes. A set of common volcanological input parameters and meteorological conditions were provided for two kinds of eruptions, representing a weak and a strong eruption column. From the different models, we compared the maximum plume height, neutral buoyancy level (where plume density equals that of the atmosphere), and level of maximum radial spreading of the umbrella cloud. We also compared the vertical profiles of eruption column properties, integrated across cross-sections of the plume (integral variables). Although the models use different numerical procedures and treatments of subgrid turbulence and particle dynamics, the inter-comparison shows qualitatively consistent results. In the weak plume case (mass eruption rate 1.5 × 106 kg s− 1), the vertical profiles of plume properties (e.g., vertical velocity, temperature) are similar among models, especially in the buoyant plume region. Variability among the simulated maximum heights is ~ 20%, whereas neutral buoyancy level and level of maximum radial spreading vary by ~ 10%. Time-averaging of the three-dimensional (3D) flow fields indicates an effective entrainment coefficient around 0.1 in the buoyant plume region, with much lower values in the jet region, which is consistent with findings of small-scale laboratory experiments. On the other hand, the strong plume case (mass eruption rate 1.5 × 109 kg s− 1) shows greater variability in the vertical plume profiles predicted by the different models. Our analysis suggests that the unstable flow dynamics in the strong plume enhances differences in the formulation and numerical solution of the models. This is especially evident in the overshooting top of the plume, which extends a significant portion (~ 1/8) of the maximum plume height. Nonetheless, overall variability in the spreading level and neutral buoyancy level is ~ 20%, whereas that of maximum height is ~ 10%. This inter-comparison study has highlighted the different capabilities of 3D volcanic plume models, and identified key features of weak and strong plumes, including the roles of jet stability, entrainment efficiency, and particle non-equilibrium, which deserve future investigation in field, laboratory, and numerical studies.
Central obesity is an independent predictor of erectile dysfunction in older men.

PubMed

Riedner, Charles Edison; Rhoden, Ernani Luis; Ribeiro, Eduardo Porto; Fuchs, Sandra Costa

2006-10-01

There is a growing body of evidence in the literature correlating erectile dysfunction to obesity. We investigated the correlation of different anthropometric indexes of central obesity to erectile dysfunction. A cross-sectional study was performed including 256 consecutive men 40 years old or older. All men completed the International Index of Erectile Function, and were evaluated routinely with a clinical history, physical examination and blood analysis for fasting serum glucose, lipid profile and serum testosterone. Anthropometric measures included body mass index, waist circumference, sagittal abdominal diameter, maximal abdominal circumference, and waist-hip, waist-thigh, waist-height, sagittal abdominal diameter-thigh and sagittal abdominal diameter-height indexes. In men 40 to 60 years old the different anthropometric indexes of central obesity were not correlated with the presence of erectile dysfunction (p > 0.05). Men older than 60 years (41%, range 61 to 81) demonstrated an association among erectile dysfunction and waist-hip index (p = 0.04), waist-thigh index (p = 0.02), sagittal abdominal diameter (p = 0.03), sagittal abdominal diameter-height index (p = 0.02) and maximal abdominal circumference (p = 0.04). After logistic regression analysis an independent effect on the presence of erectile dysfunction was observed for waist-hip index (OR 8.56, 95% CI 1.44-50.73), sagittal abdominal diameter (OR 7.87, 95% CI 1.24-49.75), sagittal abdominal diameter-height index (OR 14.21, 95% CI 1.11-182.32), maximum abdominal circumference (OR 11.72, 95% CI 1.73-79.18) and waist circumference (OR 19.37, 95% CI 1.15-326.55). This study suggests that central obesity, assessed by several anthropometric indicators, is associated to the presence of erectile dysfunction in men older than 60 years. Sagittal abdominal diameter, sagittal abdominal diameter-height index, maximum abdominal circumference, waist circumference and waist-hip index were useful indicators to predict the presence of erectile dysfunction.
Photon Counting Detectors for the 1.0 - 2.0 Micron Wavelength Range

NASA Technical Reports Server (NTRS)

Krainak, Michael A.

2004-01-01

We describe results on the development of greater than 200 micron diameter, single-element photon-counting detectors for the 1-2 micron wavelength range. The technical goals include quantum efficiency in the range 10-70%; detector diameter greater than 200 microns; dark count rate below 100 kilo counts-per-second (cps), and maximum count rate above 10 Mcps.
76 FR 26280 - Vermont Marble Power Division of Omya Inc.; Notice of Application Accepted for Filing, Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-06

...); (6) an additional steel structure measuring 28 by 48 feet attached to the original powerhouse... maximum water surface elevation of 469.5 feet mean sea level (M.S.L); (3) a gated-forebay intake structure...: A 9-foot- diameter, 460-foot-long, riveted steel penstock that decreases to 8 feet diameter; and a 7...
Relation of Stem Diameter, Branch Basal Area, and Leaf Biomass in Rapidly Growing Loblolly Pine

Treesearch

Thomas M. Williams; Charles A. Gresham

2004-01-01

Twenty loblolly pines, growing in International Paperâs maximum growth experiment at Bainbridge GA, were destructively sampled at the end of the sixth growing season. Ten trees in the control and 10 in the maximum treatment were sampled. All trees were planted at a 2.4- by 3.6-m spacing and grown with complete competition control. The maximum trees also received...

Essential features of long-term changes of areas and diameters of sunspot groups in solar activity cycles 12-24

NASA Astrophysics Data System (ADS)

Efimenko, V. M.; Lozitsky, V. G.

2018-06-01

We analyze the Greenwich catalog data on areas of sunspot groups of last thirteen solar cycles. Various parameters of sunspots are considered, namely: average monthly smoothed areas, maximum area for each year and equivalent diameters of groups of sunspots. The first parameter shows an exceptional power of the 19th cycle of solar activity, which appears here more contrastively than in the numbers of spots (that is, in Wolf's numbers). It was found that in the maximum areas of sunspot groups for a year there is a unique phenomenon: a short and high jump in the 18th cycle (in 1946-1947) that has no analogues in other cycles. We also studied the integral distributions for equivalent diameters and found the following: (a) the average value of the index of power-law approximation is 5.4 for the last 13 cycles and (b) there is reliable evidence of Hale's double cycle (about 44 years). Since this indicator reflects the dispersion of sunspot group diameters, the results obtained show that the convective zone of the Sun generates embryos of active regions in different statistical regimes which change with a cycle of about 44 years.
Cryogenic vertical test facility for the SRF cavities at BNL

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

Than, R.; Liaw, CJ; Porqueddu, R.

2011-03-28

A vertical test facility has been constructed to test SRF cavities and can be utilized for other applications. The liquid helium volume for the large vertical dewar is approximate 2.1m tall by 1m diameter with a clearance inner diameter of 0.95m after the inner cold magnetic shield installed. For radiation enclosure, the test dewar is located inside a concrete block structure. The structure is above ground, accessible from the top, and equipped with a retractable concrete roof. A second radiation concrete facility, with ground level access via a labyrinth, is also available for testing smaller cavities in 2 smaller dewars.more » The cryogenic transfer lines installation between the large vertical test dewar and the cryo plant's sub components is currently near completion. Controls and instrumentations wiring are also nearing completion. The Vertical Test Facility will allow onsite testing of SRF cavities with a maximum overall envelope of 0.9 m diameter and 2.1 m height in the large dewar and smaller SRF cavities and assemblies with a maximum overall envelope of 0.66 m diameter and 1.6 m height.« less
Implant-bone interface stress distribution in immediately loaded implants of different diameters: a three-dimensional finite element analysis.

PubMed

Ding, Xi; Zhu, Xing-Hao; Liao, Sheng-Hui; Zhang, Xiu-Hua; Chen, Hong

2009-07-01

To establish a 3D finite element model of a mandible with dental implants for immediate loading and to analyze stress distribution in bone around implants of different diameters. Three mandible models, embedded with thread implants (ITI, Straumann, Switzerland) with diameters of 3.3, 4.1, and 4.8 mm, respectively, were developed using CT scanning and self-developed Universal Surgical Integration System software. The von Mises stress and strain of the implant-bone interface were calculated with the ANSYS software when implants were loaded with 150 N vertical or buccolingual forces. When the implants were loaded with vertical force, the von Mises stress concentrated on the mesial and distal surfaces of cortical bone around the neck of implants, with peak values of 25.0, 17.6 and 11.6 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains (5854, 4903, 4344 muepsilon) were located on the buccal cancellous bone around the implant bottom and threads of implants. The stress and strain were significantly lower (p < 0.05) with the increased diameter of implant. When the implants were loaded with buccolingual force, the peak von Mises stress values occurred on the buccal surface of cortical bone around the implant neck, with values of 131.1, 78.7, and 68.1 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains occurred on the buccal surface of cancellous bone adjacent to the implant neck, with peak values of 14,218, 12,706, and 11,504 microm, respectively. The stress of the 4.1-mm diameter implants was significantly lower (p < 0.05) than those of 3.3-mm diameter implants, but not statistically different from that of the 4.8 mm implant. With an increase of implant diameter, stress and strain on the implant-bone interfaces significantly decreased, especially when the diameter increased from 3.3 to 4.1 mm. It appears that dental implants of 10 mm in length for immediate loading should be at least 4.1 mm in diameter, and uniaxial loading to dental implants should be avoided or minimized.
High-Subsonic Performance Characteristics and Boundary-Layer Investigations of a 12 deg 10-Inch-Inlet-Diameter Conical Diffuser

DTIC Science & Technology

1950-05-11

available condition supersonic flow was obtained as far as K.5 inches downstream from the diffueer inlet with a maximum Mach number of M % 1.5...Boundary—layer total-pressure measurements were made with the rake shown in figure k. The tubes varied in size from 0.030-Inch outside diameter...at the wall to 0.050—inch outside diameter farther out. A static-pressure tube was mounted on the rake to measure static pressures at the same
Optimizing parameter of particle damping based on Leidenfrost effect of particle flows

NASA Astrophysics Data System (ADS)

Lei, Xiaofei; Wu, Chengjun; Chen, Peng

2018-05-01

Particle damping (PD) has strongly nonlinearity. With sufficiently vigorous vibration conditions, it always plays excellent damping performance and the particles which are filled into cavity are on Leidenfrost state considered in particle flow theory. For investigating the interesting phenomenon, the damping effect of PD on this state is discussed by the developed numerical model which is established based on principle of gas and solid. Furtherly, the numerical model is reformed and applied to study the relationship of Leidenfrost velocity with characteristic parameters of PD such as particle density, diameter, mass packing ratio and diameter-length ratio. The results indicate that particle density and mass packing ratio can drastically improve the damping performance as opposed as particle diameter and diameter-length ratio, mass packing ratio and diameter-length ratio can low the excited intensity for Leidenfrost state. For discussing the application of the phenomenon in engineering, bound optimization by quadratic approximation (BOBYQA) method is employed to optimize mass packing ratio of PD for minimize maximum amplitude (MMA) and minimize total vibration level (MTVL). It is noted that the particle damping can drastically reduce the vibrating amplitude for MMA as Leidenfrost velocity equal to the vibrating velocity relative to maximum vibration amplitude. For MTVL, larger mass packing ratio is best option because particles at relatively wide frequency range is adjacent to Leidenfrost state.
Measurement of the point spread function and effective area of the Solar-A Soft X-ray Telescope mirror

NASA Technical Reports Server (NTRS)

Lemen, J. R.; Claflin, E. S.; Brown, W. A.; Bruner, M. E.; Catura, R. C.

1989-01-01

A grazing incidence solar X-ray telescope, Soft X-ray Telescope (SXT), will be flown on the Solar-A satellite in 1991. Measurements have been conducted to determine the focal length, Point Spread Function (PSF), and effective area of the SXT mirror. The measurements were made with pinholes, knife edges, a CCD, and a proportional counter. The results show the 1/r character of the PSF, and indicate a half power diameter of 4.9 arcsec and an effective area of 1.33 sq cm at 13.3 A (0.93 keV). The mirror was found to provide a high contrast image with very little X-ray scattering.
Spread of large LNG pools on the sea.

PubMed

Fay, J A

2007-02-20

A review of the standard model of LNG pool spreading on water, comparing it with the model and experiments on oil pool spread from which the LNG model is extrapolated, raises questions about the validity of the former as applied to spills from marine tankers. These questions arise from the difference in fluid density ratios, in the multi-dimensional flow at the pool edge, in the effects of LNG pool boiling at the LNG-water interface, and in the model and experimental initial conditions compared with the inflow conditions from a marine tanker spill. An alternate supercritical flow model is proposed that avoids these difficulties; it predicts significant increase in the maximum pool radius compared with the standard model and is partially corroborated by tests of LNG pool fires on water. Wind driven ocean wave interaction has little effect on either spread model.
Measurement of multipath delay profile in land mobile satellite channels

NASA Technical Reports Server (NTRS)

Ikegami, Tetsushi; Arakaki, Yoshiya; Wakana, Hiromitsu; Suzuki, Ryutaro

1993-01-01

Mobile satellite communication channel has been evaluated mainly with fading statistics of signal. When bandwidth of transmitting signal becomes wider, frequency selectivity of fading becomes a significant factor of the channel. Channel characteristics, not only signal variation but multipath delay spread should be evaluated. A multipath measurement system is proposed and developed for mobile satellite applications. With this system and ETS-V satellite, multipath delay profiles are measured in various environments including Tokyo metropolis and Sapporo city at 1.5 GHz. Results show that the maximum excess delay is within 1 microsec and the maximum delay spread is 0.2 microsecs at elevation angles of 40 to 47 degrees. In wideband signal transmission of about 1 MHz and more, designers should consider the effect of selective fading due to the multipath of land mobile satellite channel.
Posture-related distribution of hyperbaric bupivacaine in cerebro-spinal fluid is influenced by spinal needle characteristics.

PubMed

Mardirosoff, C; Dumont, L; Deyaert, M; Leconte, M

2001-07-01

No studies have evaluated the relationship between duration of time sitting and spinal needle type on the maximal spread of local anaesthetics. The few trials available have studied the influence of time spent sitting on the spread of anaesthesia without standardising spinal needle types, and have not found any effect. In this randomised, blinded study, 60 patients scheduled for elective orthopaedic surgery of the lower limbs were divided into 4 groups. With the patient sitting erect, 15 mg hyperbaric bupivacaine were injected in a standard manner through a 24G Sprotte or a 27G Whitacre needle and patients were placed supine after 1 min (24G/1 group and 27G/1 group) or 4 min (24G/4 group and 27G/4 group). Time to achieve maximum block height after injection was similar in all groups. Block height levels were significantly lower at all time points for the 24G/4 group. Maximum block heights were Th4 in the 24G/1, 27G/1 and 27G/4 groups, and Th6 in the 24G/4 group (P<0.0001). In a standard spinal anaesthesia procedure, when different lengths of time spent sitting are compared, spinal needle characteristics influence the maximum spread of hyperbaric bupivacaine. However, within the limits of our study, a two-segment difference in block height is too small to consider using spinal needles as valuable tools to control block height during spinal anaesthesia in our daily practice.
Heat transfer to small horizontal cylinders immersed in a fluidized bed

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

Friedman, J.; Koundakjian, P.; Naylor, D.

2006-10-15

Heat transfer to horizontal cylinders immersed in fluidized beds has been extensively studied, but mainly in the context of heat transfer to boiler tubes in coal-fired beds. As a result, most correlations in the literature have been derived for cylinders of 25-50 mm diameter in vigorously fluidizing beds. In recent years, fluidized bed heat treating furnaces fired by natural gas have become increasingly popular, particularly in the steel wire manufacturing industry. These fluidized beds typically operate at relatively low fluidizing rates and with small diameter wires (1-6 mm). Nusselt number correlations developed based on boiler tube studies do not extrapolatemore » down to these small size ranges and low fluidizing rates. In order to obtain reliable Nusselt number data for these size ranges, an experimental investigation has been undertaken using two heat treating fluidized beds; one a pilot-scale industrial unit and the other a lab-scale (300 mm diameter) unit. Heat transfer measurements were obtained using resistively heated cylindrical samples ranging from 1.3 to 9.5 mm in diameter at fluidizing rates ranging from approximately 0.5 x G{sub mf} (packed bed condition) to over 10 x G{sub mf} using aluminum oxide sand particles ranging from d{sub p}=145-330 {mu}m (50-90 grit). It has been found that for all cylinder sizes tested, the Nusselt number reaches a maximum near 2 x G{sub mf}, then remains relatively steady ({+-}5-10%) to the maximum fluidizing rate tested, typically 8-12xG{sub mf}. A correlation for maximum Nusselt number is developed.« less
Incidence, treatment and outcome of rectal stenosis following transanal endoscopic microsurgery.

PubMed

Barker, J A; Hill, J

2011-09-01

As an alternative to more radical abdominal surgery, transanal endoscopic microsurgery (TEM) offers a minimally invasive solution for the excision of certain rectal polyps and early-stage rectal tumours. The patient benefits of TEM as compared to radical abdominal surgery are clear; nevertheless, some drawback is possible. The aim of our study was to determine the risk factors, treatment and outcomes of rectal stenosis following TEM. We analysed a series of 354 consecutive patients who underwent TEM for benign or malignant rectal tumours between 1997 and 2009. We recorded the maximum histological diameter of the lesion, and whether the lesion was circumferential. Rectal stenosis was defined as a rectal narrowing not allowing passage of a 12 mm sigmoidoscope. Histological results with a measured specimen diameter were available in 304 of the 354 cases. There were 11 stenoses in total (3.6%), 7 stenoses due to 9 circumferential lesions (78%) and 4 due to lesions with a maximum diameter ≥ 5 cm (3.2%). Two patients presented as emergencies, and the other 9 patients reported symptoms of increased stool frequency at follow-up. Three of the stenoses were associated with recurrent disease. All stenoses were treated by a combination of endoscopic/radiological balloon dilatation or surgically with Hegar's dilators. A median of two procedures were required to treat stenoses until resolution of symptoms. Rectal stenosis following TEM excision is rare. It is predictable in patients with circumferential lesions but is rare in patients with non-circumferential lesions with a maximum diameter ≥ 5 cm. It is effectively treated with surgical or balloon dilatation. Most patients require repeated treatments.
A passerine spreads its tail to facilitate a rapid recovery of its body posture during hovering

PubMed Central

Su, Jian-Yuan; Ting, Shang-Chieh; Chang, Yu-Hung; Yang, Jing-Tang

2012-01-01

We demonstrate experimentally that a passerine exploits tail spreading to intercept the downward flow induced by its wings to facilitate the recovery of its posture. The periodic spreading of its tail by the White-eye bird exhibits a phase correlation with both wingstroke motion and body oscillation during hovering flight. During a downstroke, a White-eye's body undergoes a remarkable pitch-down motion, with the tail undergoing an upward swing. This pitch-down motion becomes appropriately suppressed at the end of the downstroke; the bird's body posture then recovers gradually to its original status. Employing digital particle-image velocimetry, we show that the strong downward flow induced by downstroking the wings serves as an external jet flow impinging upon the tail, providing a depressing force on the tail to counteract the pitch-down motion of the bird's body. Spreading of the tail enhances a rapid recovery of the body posture because increased forces are experienced. The maximum force experienced by a spread tail is approximately 2.6 times that of a non-spread tail. PMID:22258552
A passerine spreads its tail to facilitate a rapid recovery of its body posture during hovering.

PubMed

Su, Jian-Yuan; Ting, Shang-Chieh; Chang, Yu-Hung; Yang, Jing-Tang

2012-07-07

We demonstrate experimentally that a passerine exploits tail spreading to intercept the downward flow induced by its wings to facilitate the recovery of its posture. The periodic spreading of its tail by the White-eye bird exhibits a phase correlation with both wingstroke motion and body oscillation during hovering flight. During a downstroke, a White-eye's body undergoes a remarkable pitch-down motion, with the tail undergoing an upward swing. This pitch-down motion becomes appropriately suppressed at the end of the downstroke; the bird's body posture then recovers gradually to its original status. Employing digital particle-image velocimetry, we show that the strong downward flow induced by downstroking the wings serves as an external jet flow impinging upon the tail, providing a depressing force on the tail to counteract the pitch-down motion of the bird's body. Spreading of the tail enhances a rapid recovery of the body posture because increased forces are experienced. The maximum force experienced by a spread tail is approximately 2.6 times that of a non-spread tail.
The Hengill geothermal area, Iceland: variation of temperature gradients deduced from the maximum depth of seismogenesis

USGS Publications Warehouse

Foulger, G.R.

1995-01-01

Given a uniform lithology and strain rate and a full seismic data set, the maximum depth of earthquakes may be viewed to a first order as an isotherm. These conditions are approached at the Hengill geothermal area, S. Iceland, a dominantly basaltic area. The temperature at which seismic failure ceases for the strain rates likely at the Hengill geothermal area is determined by analogy with oceanic crust, and is about 650 ?? 50??C. The topographies of the top and bottom of the seismogenic layer were mapped using 617 earthquakes. The thickness of the seismogenic layer is roughly constant and about 3 km. A shallow, aseismic, low-velocity volume within the spreading plate boundary that crosses the area occurs above the top of the seismogenic layer and is interpreted as an isolated body of partial melt. The base of the seismogenic layer has a maximum depth of about 6.5 km beneath the spreading axis and deepens to about 7 km beneath a transform zone in the south of the area. -from Author
Annular ring zoom system using two positive axicons

NASA Astrophysics Data System (ADS)

Dickey, Fred M.; Conner, Jacob D.

2011-10-01

The production of an annular ring of light with a variable diameter has applications in laser material processing and machining, particle manipulation, and corneal surgery. This can readily be accomplished using a positive and negative axicon pair. However, negative axicons are very expensive and difficult to obtain with small diameters. In this paper, we present a design of an annular ring zoom system using two positive axicons. One axicon is placed a distance before a primary lens that is greater than some prescribed minimum, and the second axicon is placed after the primary lens. The position of the second axicon determines the ring diameter. The ring diameter can be zoomed from some maximum design size to a zero diameter ring (spot). Experimental results from a developmental system will be presented.
Diameter-Constrained Steiner Tree

NASA Astrophysics Data System (ADS)

Ding, Wei; Lin, Guohui; Xue, Guoliang

Given an edge-weighted undirected graph G = (V,E,c,w), where each edge e ∈ E has a cost c(e) and a weight w(e), a set S ⊆ V of terminals and a positive constant D 0, we seek a minimum cost Steiner tree where all terminals appear as leaves and its diameter is bounded by D 0. Note that the diameter of a tree represents the maximum weight of path connecting two different leaves in the tree. Such problem is called the minimum cost diameter-constrained Steiner tree problem. This problem is NP-hard even when the topology of Steiner tree is fixed. In present paper we focus on this restricted version and present a fully polynomial time approximation scheme (FPTAS) for computing a minimum cost diameter-constrained Steiner tree under a fixed topology.
Improved attachment of mesenchymal stem cells on super-hydrophobic TiO2 nanotubes.

PubMed

Bauer, Sebastian; Park, Jung; von der Mark, Klaus; Schmuki, Patrik

2008-09-01

Self-organized layers of vertically orientated TiO(2) nanotubes providing defined diameters ranging from 15 up to 100nm were grown on titanium by anodic oxidation. These TiO(2) nanotube layers show super-hydrophilic behavior. After coating TiO(2) nanotube layers with a self-assembled monolayer (octadecylphosphonic acid) they showed a diameter-dependent wetting behavior ranging from hydrophobic (108+/-2 degrees ) up to super-hydrophobic (167+/-2 degrees ). Cell adhesion, spreading and growth of mesenchymal stem cells on the unmodified and modified nanotube layers were investigated and compared. We show that cell adhesion and proliferation are strongly affected in the super-hydrophobic range. Adsorption of extracellular matrix proteins as fibronectin, type I collagen and laminin, as well as bovine serum albumin, on the coated and uncoated surfaces showed a strong influence on wetting behavior and dependence on tube diameter.
Disease Spreading Model with Partial Isolation

NASA Astrophysics Data System (ADS)

Chakraborty, Abhijit; Manna, S. S.

2013-08-01

The effect of partial isolation has been studied in disease spreading processes using the framework of susceptible-infected-susceptible (SIS) and susceptible-infected-recovered (SIR) models. The partial isolation is introduced by imposing a restriction: each infected individual can probabilistically infect up to a maximum number n of his susceptible neighbors, but not all. It has been observed that the critical values of the spreading rates for endemic states are non-zero in both models and decrease as 1/n with n, on all graphs including scale-free graphs. In particular, the SIR model with n = 2 turned out to be a special case, characterized by a new bond percolation threshold on square lattice.
Spatial spread of the West Africa Ebola epidemic.

PubMed

Kramer, Andrew M; Pulliam, J Tomlin; Alexander, Laura W; Park, Andrew W; Rohani, Pejman; Drake, John M

2016-08-01

Controlling Ebola outbreaks and planning an effective response to future emerging diseases are enhanced by understanding the role of geography in transmission. Here we show how epidemic expansion may be predicted by evaluating the relative probability of alternative epidemic paths. We compared multiple candidate models to characterize the spatial network over which the 2013-2015 West Africa epidemic of Ebola virus spread and estimate the effects of geographical covariates on transmission during peak spread. The best model was a generalized gravity model where the probability of transmission between locations depended on distance, population density and international border closures between Guinea, Liberia and Sierra Leone and neighbouring countries. This model out-performed alternative models based on diffusive spread, the force of infection, mobility estimated from cell phone records and other hypothesized patterns of spread. These findings highlight the importance of integrated geography to epidemic expansion and may contribute to identifying both the most vulnerable unaffected areas and locations of maximum intervention value.
Spatial spread of the West Africa Ebola epidemic

PubMed Central

Pulliam, J. Tomlin; Alexander, Laura W.; Rohani, Pejman; Drake, John M.

2016-01-01

Controlling Ebola outbreaks and planning an effective response to future emerging diseases are enhanced by understanding the role of geography in transmission. Here we show how epidemic expansion may be predicted by evaluating the relative probability of alternative epidemic paths. We compared multiple candidate models to characterize the spatial network over which the 2013–2015 West Africa epidemic of Ebola virus spread and estimate the effects of geographical covariates on transmission during peak spread. The best model was a generalized gravity model where the probability of transmission between locations depended on distance, population density and international border closures between Guinea, Liberia and Sierra Leone and neighbouring countries. This model out-performed alternative models based on diffusive spread, the force of infection, mobility estimated from cell phone records and other hypothesized patterns of spread. These findings highlight the importance of integrated geography to epidemic expansion and may contribute to identifying both the most vulnerable unaffected areas and locations of maximum intervention value. PMID:27853607

A 16-year evaluation of effects of ripping on shortleaf pine on a Missouri ozarks site

Treesearch

David Gwaze; Carl Hauser; Mark Johanson

2006-01-01

A shortleaf pine (Pinus echinata Mill.) ripping study was established by the Missouri Department of Conservation in March 1988 at the Logan Creek Conservation Area. The objective of the study was to evaluate the effects of ripping on survival, height, diameter, volume, crown spread, and free-to-grow status of planted shortleaf pine seedlings. Ripping...
Incorporation of buriti endocarp flour in gluten-free whole cookies as potential source of dietary fiber.

PubMed

Becker, Fernanda Salamoni; Damiani, Clarissa; de Melo, Adriane Alexandre Machado; Borges, Paulo Rogério Siriano; Boas, Eduardo Valério de Barros Vilas

2014-12-01

Cookies were prepared by replacing a mixture of brown rice flour (70%) and corn starch (30%) (BRFCS) by buriti endocarp flour (BEF) (0, 5, 10, 15 or 20%). BEF figured as a potential source of dietary fiber (70.53 g 100 g(-1)), especially of insoluble fiber (67.50 g 100 g(-1)), and gluten-free whole cookies showed increased dietary fiber content by adding 5, 10, 15 and 20% BEF (8.58 to 20.02 g 100 g(-1)) when compared to control cookie (6.91 g 100 g(-1)). The addition of BEF affected diameter, spread ratio, color and texture of cookies. All cookies added with BEF were darker, harder and presented smaller diameter and smaller spread ratio than the control cookie. These difference increased proportionally to level of substitution of BRFSC by BEF. Gluten-free whole cookies with up to 15% BEF were well accepted by consumers. Therefore, the use of BEF in cookies may increase the availability of functional ingredients source of dietary fiber for celiac consumers, add economic value to buriti processing by-products and decrease environmental impacts due to the high amounts of waste generated by buriti processing industries.
Pipeline welding goes mechanized

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

Beeson, R.

1999-11-01

Spread four has bugs in the cornfield--but not to worry. The bug referred to here is a mechanized welding bug, specifically a single welding head, computer-aided gas metal arc (GMAW) system from CRC-Evans Automatic Welding powered by a Miller Electric XMT{reg{underscore}sign} 304 inverter-based welding machine. The bug operator and owner of 32 inverters is Welded Construction, L.P., of Perrysburgh, Ohio. Spread four is a 147-mile stretch of the Alliance Pipeline system (Alliance) cutting through the cornfields of northeast Iowa. While used successfully in Canada and Europe for onshore and offshore pipeline construction for 30 years, this is the first large-scalemore » use of mechanized welding in the US on a cross-country pipeline. On longer, larger-diameter and thicker-wall pipe projects--the Alliance mainline has 1,844 miles of pipe, most of it 36-in. diameter with a 0.622-in. wall thickness--mechanized GMAW offers better productivity than manual shielded metal arc welding (SMAW). In addition, high-strength steels, such as the API 5L Grade X70 pipe used on the Alliance, benefit from the low-hydrogen content of certain solid and tubular wire electrodes.« less
Hydrostatic Bearing Pad Maximum Load and Overturning Conditions for the 70-meter Antenna

NASA Technical Reports Server (NTRS)

Mcginness, H. D.

1985-01-01

The reflector diameters of the 64-m antennas were increased to 70-m. In order to evaluate the minimum film thickness of the hydrostatic bearing which supports the antenna weight, it is first necessary to have a good estimation of the maximum operational load on the most heavily loaded bearing pad. The maximum hydrostatic bearing load is shown to be sufficiently small and the ratios of stabilizing to over turning moments are ample.
Whole-tree harvesting of pines with taproot attached

Treesearch

P. Koch

1974-01-01

The taproot of a 15- to 3O-yearold slash pine, with lateral roots pruned away, weighs about 20% as much as the bark-free merchantable stem to a four-inch top (dry-weight basis). Maximum taproot diameter, a few inches below ground level, is 1.5 to two times stem diameter at breast height. Length in sandy loam soils is commonly three to five feet.
Five Years' Growth of Pruned and Unpruned Cottonwood Planted at 40- by 40-Foot Spacing

Treesearch

Roger M. Krinard

1979-01-01

Four pruning treatments have been applied for 5 years on cottonwood (Populus deltoides Bartr.) select clone Stoneville 66, planted at 40- by 40-ft spacing. As pruning severity increased, average diameter and maximum crown width decreased. Diameters ranged from 9.2 inches for trees pruned half of height yearly to 11.4 inches for unpruned trees; crown widths ranged from...
Modeling Caribbean tree stem diameters from tree height and crown width measurements

Treesearch

Thomas Brandeis; KaDonna Randolph; Mike Strub

2009-01-01

Regression models to predict diameter at breast height (DBH) as a function of tree height and maximum crown radius were developed for Caribbean forests based on data collected by the U.S. Forest Service in the Commonwealth of Puerto Rico and Territory of the U.S. Virgin Islands. The model predicting DBH from tree height fit reasonably well (R2 = 0.7110), with...
A comparison of hydraulic architecture in three similarly sized woody species differing in their maximum potential height

Treesearch

Katherine A. McCulloh; Daniel M. Johnson; Joshua Petitmermet; Brandon McNellis; Frederick C. Meinzer; Barbara Lachenbruch; Nathan Phillips

2015-01-01

The physiological mechanisms underlying the short maximum height of shrubs are not understood. One possible explanation is that differences in the hydraulic architecture of shrubs compared with co-occurring taller trees prevent the shrubs from growing taller. To explore this hypothesis, we examined various hydraulic parameters, including vessel lumen diameter,...
A surface fuel classification for estimating fire effects

Treesearch

Duncan C. Lutes; Robert E. Keane; John F. Caratti

2009-01-01

We present a classification of duff, litter, fine woody debris, and logs that can be used to stratify a project area into sites with fuel loading that yield significantly different emissions and maximum soil surface temperature. Total particulate matter smaller than 2.5?m in diameter and maximum soil surface temperature were simulated using the First...
Change of heart dimensions and function during pregnancy in goats.

PubMed

Szaluś-Jordanow, Olga; Czopowicz, Michał; Witkowski, Lucjan; Moroz, Agata; Mickiewicz, Marcin; Frymus, Tadeusz; Markowska-Daniel, Iwona; Bagnicka, Emilia; Kaba, Jarosław

2018-03-08

The study aimed to evaluate the effect of pregnancy on heart diameters and function in goats. Transthoracic echocardiography of 12 female dairy goats of two Polish regional breeds was performed. A Mindray M7 diagnostic ultrasound system with Phased Array transducer was used. Simultaneously, electrocardiography was recorded. All animals were examined four times - at mating season, at the end of the first trimester, at the end of the second trimester and just before kidding. Eleven measurements were taken each time: aortic and left atrial diameter (AoD and LAD), right and left ventricular internal diameter in diastole (RVIDd and LVIDd), left ventricular internal diameter in systole (LVIDs), inter-ventricular septum thickness in diastole and systole (IVSd and IVSd) and left ventricular posterior wall in diastole and systole (LVPWd and LVPWs), maximum left and right ventricular outflow tract velocity (RVOT Vmax and LVOT Vmax). Nine consecutive measurements were derived: the ratio of the left atrial diameter to the aortic diameter (AoD/LAD), left ventricular fractional shortening (FS%), left ventricular ejection fraction (EF%), maximum outflow tract pressure gradients (RVOT PGmax and LVOT PGmax), left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV), stroke volume (SV) and cardiac output (CO). HR, LAD, LVPWs, IVSs increased significantly in the first trimester. AoD and RVIDd were significantly higher around parturition. LVIDd, FS%, EF%, SV and CO rose both in the first and third trimester. No measurement decreased during pregnancy. The study confirms that pregnancy causes changes in the heart size and functioning. Copyright © 2018. Published by Elsevier Ltd.
Description of a new species of the genus Mongolotettix Rehn, 1928 (Orthoptera: Acrididae) from Fujian, China.

PubMed

Chen, Shen-Zhi; Shi, Jian-Ping; Dai, Li

2018-04-17

A new species of the genus Mongolotettix Rehn, 1928 from Fujian, China is described in this paper. The new species Mongolotettix.fujianensis sp. nov. is similar to M. wulingyuanensis Shi, Liu et Li, 2016, but differs from the latter by maximum width of cubital area 1.4 times maximum width of medial area in tegmina of male; body small, length of body ♂ 21.5. mm, ♀ 30.6 mm; vertical diameter eye 1.3 times horizontal diameter in male; hind femur of male with 103 stridulatory pegs on inner side and epiphallus with indistinct projection on inner side of lateral plates. Type specimens are deposited in the Shanghai Entomological Museum, Chinese Academy of Sciences, Shanghai, 200032, China.
Internal V-Band Clamp

DOEpatents

Vaughn, Mark R.; Hafenrichter, Everett S.; Chapa, Agapito C.; Harris, Steven M.; Martinez, Marcus J.; Baty, Roy S.

2006-02-28

A system for clamping two tubular members together in an end-to-end relationship uses a split ring with a V-shaped outer rim that can engage a clamping surface on each member. The split ring has a relaxed closed state where the ends of the ring are adjacent and the outside diameter of the split ring is less than the minimum inside diameter of the members at their ends. The members are clamped when the split ring is spread into an elastically stretched position where the ring rim is pressed tightly against the interior surfaces of the members. Mechanisms are provided for removing the spreader so the split ring will return to the relaxed state, releasing the clamped members.
Comparison of in vivo eccentricity and symmetry indices between metallic stents and bioresorbable vascular scaffolds: insights from the ABSORB and SPIRIT trials.

PubMed

Brugaletta, Salvatore; Gomez-Lara, Josep; Diletti, Roberto; Farooq, Vasim; van Geuns, Robert Jan; de Bruyne, Bernard; Dudek, Dariusz; Garcia-Garcia, Hector M; Ormiston, John A; Serruys, Patrick W

2012-02-01

To compare the geometrical parameters of a bioresorbable vascular scaffold (BVS) with a standard metallic stent. The introduction of polymeric bioresorbable materials in the design of novel coronary scaffolds may affect some geometrical parameters, such as eccentricity and symmetry indices, previously introduced as IVUS criteria for optimal metallic stent deployment. From ABSORB Cohort A, ABSORB Cohort B, SPIRIT I, and SPIRIT II, all patients implanted with BVS 1.0, BVS 1.1, or XIENCE V, respectively and intravascular ultrasound analyses post-implantation were selected. The eccentricity index was calculated frame by frame and expressed as an average per device (minimum diameter/maximum diameter). The symmetry index of the device was reported as ([maximum diameter - minimum diameter]/maximum diameter). Six months major adverse cardiac events (MACE) were analyzed. A total of 242 patients were selected (BVS 1.0: n = 28, BVS 1.1: n = 94, XIENCE V: n = 120). The BVS exhibited a significantly lower eccentricity index (BVS 1.0: 0.83 ± 0.09; BVS 1.1: 0.85 ± 0.08; XIENCE V: 0.90 ± 0.06; P < 0.01) and a significantly higher symmetry index (BVS 1.0: 0.30 ± 0.07; BVS 1.1: 0.31 ± 0.06, XIENCE V 0.26 ± 0.07; P < 0.01) as compared to the XIENCE V. An inverse correlation was found between the symmetry and eccentricity indices for both (BVS r = -0.69, P < 0.01; XIENCE V r = -0.61, P < 0.01). No differences in MACE were detected between the groups according to their geometrical parameters. The introduction of a new polymeric material in the design of BVS resulted in a lower eccentricity index and a higher symmetry index as compared to metallic stents, without detectable impact in MACE, at 6 months. Copyright © 2011 Wiley Periodicals, Inc.
Efficacy of losartan vs. atenolol for the prevention of aortic dilation in Marfan syndrome: a randomized clinical trial.

PubMed

Forteza, Alberto; Evangelista, Arturo; Sánchez, Violeta; Teixidó-Turà, Gisela; Sanz, Paz; Gutiérrez, Laura; Gracia, Teresa; Centeno, Jorge; Rodríguez-Palomares, José; Rufilanchas, Juan Jose; Cortina, José; Ferreira-González, Ignacio; García-Dorado, David

2016-03-21

To determine the efficacy of losartan vs. atenolol in aortic dilation progression in Marfan syndrome (MFS) patients. A phase IIIb, randomized, parallel, double-blind study was conducted in 140 MFS patients, age range: 5-60 years, with maximum aortic diameter <45 mm who received losartan (n = 70) or atenolol (n = 70). Doses were raised to a maximum of 1.4 mg/kg/day or 100 mg/day. The primary end-point was the change in aortic root and ascending aorta maximum diameter indexed by body surface area on magnetic resonance imaging after 36 months of treatment. No serious drug-related adverse effects were observed. Five patients presented aortic events during a follow-up (one in the losartan and four in the atenolol groups, P = 0.366). After 3 years of follow-up, aortic root diameter increased significantly in both groups: 1.1 mm (95% CI 0.6-1.6) in the losartan and 1.4 mm (95% CI 0.9-1.9) in the atenolol group, with aortic dilatation progression being similar in both groups: absolute difference between losartan and atenolol -0.3 mm (95% CI -1.1 to 0.4, P = 0.382) and indexed by BSA -0.5 mm/m2 (95% CI -1.2 to 0.1, P = 0.092). Similarly, no significant differences were found in indexed ascending aorta diameter changes between the losartan and atenolol groups: -0.3 mm/m2 (95% CI -0.8 to 0.3, P = 0.326). Among patients with MFS, the use of losartan compared with atenolol did not result in significant differences in the progression of aortic root and ascending aorta diameters over 3 years of follow-up. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.
Particle sizing by weighted measurements of scattered light

NASA Technical Reports Server (NTRS)

Buchele, Donald R.

1988-01-01

A description is given of a measurement method, applicable to a poly-dispersion of particles, in which the intensity of scattered light at any angle is weighted by a factor proportional to that angle. Determination is then made of four angles at which the weighted intensity is four fractions of the maximum intensity. These yield four characteristic diameters, i.e., the diameters of the volume/area mean (D sub 32 the Sauter mean) and the volume/diameter mean (D sub 31); the diameters at cumulative volume fractions of 0.5 (D sub v0.5 the volume median) and 0.75 (D sub v0.75). They also yield the volume dispersion of diameters. Mie scattering computations show that an average diameter less than three micrometers cannot be accurately measured. The results are relatively insensitive to extraneous background light and to the nature of the diameter distribution. Also described is an experimental method of verifying the conclusions by using two microscopic slides coated with polystyrene microspheres to simulate the particles and the background.
Reproductive Ratio for the Local Spread of African Swine Fever in Wild Boars in the Russian Federation.

PubMed

Iglesias, I; Muñoz, M J; Montes, F; Perez, A; Gogin, A; Kolbasov, D; de la Torre, A

2016-12-01

African swine fever (ASF) has caused the swine industry of the Russian Federation substantial economic losses over the last 7 years, and the disease spread from there to a number of neighbouring countries. Wild boar has been involved in the spread of the disease both at local and at transboundary levels. Understanding ASF dynamics in wild boars is prerequisite to preventing the spread and to designing and applying effective surveillance and control plans. The reproductive ratio (R 0 ) is an epidemiological indicator commonly used to quantify the extent of disease spread. Here, it was estimated in nine spatio-temporal clusters of ASF in wild boar cases in the Russian Federation (2007-2013). Clusters were defined by exploring the maximum distance of association of ASF cases using K Ripley analysis and spatio-temporal scan statistics. A maximum spatial association of 133 km in wild boar cases was identified which is within de the conventional radius of surveillance zone (100-150 km). The mean range value of R 0 = 1.58 (1.13-3.77) was lower compared to values previously estimated for ASF transmission within farms but similar to early estimates between farm (R 0 = 2-3), in domestic pigs using notification data in the Russian Federation. Results obtained provide quantitative knowledge on the epidemiology of ASF in wild boars in the Russian Federation. They identify the ASF transmission rate value in affected natural wild populations, for the first time, which could provide basis for modelling ASF transmission and suggest that current surveillance radius should be reviewed to make surveillance in wild nature more targeted and effective. © 2015 Blackwell Verlag GmbH.
Effects of topography on the functional development of human neural progenitor cells.

PubMed

Wu, Ze-Zhi; Kisaalita, William S; Wang, Lina; Zachman, Angela L; Zhao, Yiping; Hasneen, Kowser; Machacek, Dave; Stice, Steven L

2010-07-01

We have fabricated a topographical substrate with a packed polystyrene bead array for the development of cell-based assay systems targeting voltage-gated calcium channels (VGCCs). Human neural progenitor cells (H945RB.3) cultured on both flat and topographical substrates were analyzed in terms of morphological spreading, neuronal commitment, resting membrane potential (V(m)) establishment and VGCC function development. We found, by SEM imaging, that arrayed substrates, formed with both sub-micrometer (of 0.51 microm in mean diameter) and micrometer (of 1.98 microm in mean diameter) beads, were capable of promoting the spreading of the progenitor cells as compared with the flat polystyrene surfaces. With the micrometer beads, it was found that arrayed substrates facilitated the neural progenitor cells' maintenance of less negative V(m) values upon differentiation with bFGF starvation, which favored predominant neuronal commitment. Almost all the progenitor cells were responsive to 50 mM K(+) depolarization with an increase in [Ca(2+)](i) either before or upon differentiation, suggesting the expression of functional VGCCs. Compared to the flat polystyrene surfaces, microbead arrayed substrates facilitated the development of higher VGCC responsiveness by the progenitor cells upon differentiation. The enhancement of both VGCC responsiveness and cell spreading by arrays of micrometer beads was most significant on day 14 into differentiation, which was the latest time point of measurement in this study. This study thus rationalized the possibility for future substrate topography engineering to manipulate ion channel function and to meet the challenge of low VGCC responsiveness found in early drug discovery.
Variation and Heritability in Hair Diameter and Curvature in an Australian Twin Sample.

PubMed

Ho, Yvonne Y W; Brims, Mark; McNevin, Dennis; Spector, Timothy D; Martin, Nicholas G; Medland, Sarah E

2016-08-01

Hair diameter and curvature are two characteristics of human scalp hair used in forensic contexts. While previous data show that subjective categorization of hair curvature is highly heritable, the heritability of objectively measured curvature and diameter, and variability of hair characteristics within each individual have not yet been studied. The present study measured hair diameter and curvature using an optical fiber diameter analyzer in a sample of 2,332 twins and siblings. Heritability was estimated using maximum likelihood structural equation modeling. Results show sex differences in the magnitude of genetic influence for mean diameter and curvature, with the vast majority of the variance accounted for by genetic effects in males (diameter = 86%, curvature = 53%) and females (diameter = 77%, curvature = 61%). The consistency of diameter (variance within an individual) was also highly heritable, but did not show sex limitation, with 68% of the variance accounted for by genetic factors. Moderate phenotypic correlations were seen between diameter and consistency (r = 0.3) but there was little correlation between diameter and curvature (r = -0.13). A bivariate Cholesky analysis was used to estimate the genetic and environmental correlations between hair diameter and consistency, yielding genetic correlations of r gF = 0.27 for females and r gM = 0.25 for males.
Computational predictions of flame spread over alcohol pools

NASA Technical Reports Server (NTRS)

Schiller, D. N.; Ross, H. D.; Sirignano, W. A.

1993-01-01

The effects of buoyancy and thermocapillarity on pulsating and uniform flame spread above n-propanol fuel pools have been studied using a numerical model. Data obtained indicate that the existence of pulsating flame spread is dependent upon the formation of a gas-phase recirculation cell which entrains evaporating fuel vapor in front of the leading edge of the flame. The size of the recirculation cell which is affected by the extent of liquid motion ahead of the flame, is shown to dictate whether flame spread is uniform or pulsating. The amplitude and period of the flame pulsations are found to be proportional to the maximum extent of the flow head. Under conditions considered, liquid motion was not affected appreciably by buoyancy. Horizontal convection in the liquid is the dominant mechanism for transporting heat ahead of the flame for both the pulsating and uniform regimes.
Sharpening of carbon nanocone tips during plasma-enhanced chemical vapor growth

NASA Astrophysics Data System (ADS)

Merkulov, Vladimir I.; Melechko, Anatoli V.; Guillorn, Michael A.; Lowndes, Douglas H.; Simpson, Michael L.

2001-12-01

In situ tip sharpening of vertically aligned carbon nanocones (VACNCs) was demonstrated. VACNCs were synthesized on patterned catalyst dots of 100 nm in diameter using dc plasma-enhanced chemical vapor deposition. The VACNC tip diameter was found to decrease with growth time. This enables synthesis of ultra-sharp VACNCs even for relatively large catalyst dot sizes, which is quite important for practical applications. We also find that for a given set of growth parameters the diameter of the initially formed catalyst nanoparticle determines the maximum length of the growing VACNC. The mechanism of VACNC growth and sharpening is discussed.

Flame Spread and Group-Combustion Excitation in Randomly Distributed Droplet Clouds with Low-Volatility Fuel near the Excitation Limit: a Percolation Approach Based on Flame-Spread Characteristics in Microgravity

NASA Astrophysics Data System (ADS)

Mikami, Masato; Saputro, Herman; Seo, Takehiko; Oyagi, Hiroshi

2018-03-01

Stable operation of liquid-fueled combustors requires the group combustion of fuel spray. Our study employs a percolation approach to describe unsteady group-combustion excitation based on findings obtained from microgravity experiments on the flame spread of fuel droplets. We focus on droplet clouds distributed randomly in three-dimensional square lattices with a low-volatility fuel, such as n-decane in room-temperature air, where the pre-vaporization effect is negligible. We also focus on the flame spread in dilute droplet clouds near the group-combustion-excitation limit, where the droplet interactive effect is assumed negligible. The results show that the occurrence probability of group combustion sharply decreases with the increase in mean droplet spacing around a specific value, which is termed the critical mean droplet spacing. If the lattice size is at smallest about ten times as large as the flame-spread limit distance, the flame-spread characteristics are similar to those over an infinitely large cluster. The number density of unburned droplets remaining after completion of burning attained maximum around the critical mean droplet spacing. Therefore, the critical mean droplet spacing is a good index for stable combustion and unburned hydrocarbon. In the critical condition, the flame spreads through complicated paths, and thus the characteristic time scale of flame spread over droplet clouds has a very large value. The overall flame-spread rate of randomly distributed droplet clouds is almost the same as the flame-spread rate of a linear droplet array except over the flame-spread limit.
Dependence of cancer cell adhesion kinetics on integrin ligand surface density measured by a high-throughput label-free resonant waveguide grating biosensor.

PubMed

Orgovan, Norbert; Peter, Beatrix; Bősze, Szilvia; Ramsden, Jeremy J; Szabó, Bálint; Horvath, Robert

2014-02-07

A novel high-throughput label-free resonant waveguide grating (RWG) imager biosensor, the Epic® BenchTop (BT), was utilized to determine the dependence of cell spreading kinetics on the average surface density (v(RGD)) of integrin ligand RGD-motifs. v(RGD) was tuned over four orders of magnitude by co-adsorbing the biologically inactive PLL-g-PEG and the RGD-functionalized PLL-g-PEG-RGD synthetic copolymers from their mixed solutions onto the sensor surface. Using highly adherent human cervical tumor (HeLa) cells as a model system, cell adhesion kinetic data of unprecedented quality were obtained. Spreading kinetics were fitted with the logistic equation to obtain the spreading rate constant (r) and the maximum biosensor response (Δλmax), which is assumed to be directly proportional to the maximum spread contact area (Amax). r was found to be independent of the surface density of integrin ligands. In contrast, Δλmax increased with increasing RGD surface density until saturation at high densities. Interpreting the latter behavior with a simple kinetic mass action model, a 2D dissociation constant of 1753 ± 243 μm(-2) (corresponding to a 3D dissociation constant of ~30 μM) was obtained for the binding between RGD-specific integrins embedded in the cell membrane and PLL-g-PEG-RGD. All of these results were obtained completely noninvasively without using any labels.
Integrated Design of Undepressed Collector for Low Power Gyrotron

NASA Astrophysics Data System (ADS)

Kumar, Anil; Goswami, Uttam K.; Poonia, Sunita; Singh, Udaybir; Kumar, Nitin; Alaria, M. K.; Bera, A.; Khatun, Hasina; Sinha, A. K.

2011-06-01

A 42 GHz, 200 kW continuous wave (CW) gyrotron, operating at TE03 mode is under development for the electron cyclotron resonance plasma heating of the Indian TOKAMAK system. The gyrotron is made up of an undepressed collector. The undepressed collector is simple to design and cost effective. In this paper, a detailed design study of the undepressed collector for the 42 GHz gyrotron is presented. The EGUN code is used to analyze the spent electron beam trajectory for the maximum spread to reduce the power loading on the collector surface. To achieve wall loading ≤1 kW/cm2, a collector with a length of 800 mm and a radius of 42.5 mm is designed. The design also includes the three magnet systems around the collector for maximum and uniform beam spread. The thermal and the structural analyses are done using the ANSYS code to optimize the collector structure and dimensions with tolerance.
Common iliac artery aneurysms in patients with abdominal aortic aneurysms.

PubMed

Armon, M P; Wenham, P W; Whitaker, S C; Gregson, R H; Hopkinson, B R

1998-03-01

To determine the incidence of common iliac artery (CIA) aneurysms in patients with abdominal aortic aneurysms (AAA) and to evaluate the relationship between AAA and CIA diameter. Spiral CT angiography was used to measure the maximum diameters of the abdominal aorta and the common iliac arteries of 215 patients with AAA. The median CIA diameter was 1.7 cm--significantly greater than the published mean of 1.25 (2 S.D. = 0.85-1.65) cm of an age-matched, non-vascular population. Thirty-four patients (16%) had unilateral and 26 patients (12%) bilateral CIA aneurysms > or = 2.4 cm diameter. Eight-six vessels (20%) were affected. Right CIA diameters were wider than left CIA diameters (p < 0.0001, Wilcoxon matched-pairs signed rank test). The correlation between AAA size and CIA diameter was weak. The AAA population has abnormally dilated common iliac arteries. In this population, common iliac artery aneurysms should be defined as those greater than 2.4 cm diameter. 20% of CIAs in patients with AAA are aneurysmal according to this definition.
77 FR 15798 - Notice of Intent To Repatriate Cultural Items: San Francisco State University, San Francisco, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-16

... height and 10.5 cm in diameter and is made of deer grass, sedge, redbud and bracken fern root. There are... deer grass, saw grass, redbud and bracken fern root. A tag attached to the basket was labeled... height with a maximum diameter of 18 cm and is made of deer grass, sedge, redbud and bracken fern root. A...
Power consumption analysis DBD plasma ozone generator

NASA Astrophysics Data System (ADS)

Nur, M.; Restiwijaya, M.; Muchlisin, Z.; Susan, I. A.; Arianto, F.; Widyanto, S. A.

2016-11-01

Studies on the consumption of energy by an ozone generator with various constructions electrodes of dielectric barrier discharge plasma (DBDP) reactor has been carried out. This research was done to get the configuration of the reactor, that is capable to produce high ozone concentrations with low energy consumption. BDBP reactors were constructed by spiral- cylindrical configuration, plasma ozone was generated by high voltage AC voltage up to 25 kV and maximum frequency of 23 kHz. The reactor consists of an active electrode in the form of a spiral-shaped with variation diameter Dc, and it was made by using copper wire with diameter Dw. In this research, we variated number of loops coil windings N as well as Dc and Dw. Ozone concentrations greater when the wire's diameter Dw and the diameter of the coil windings applied was greater. We found that impedance greater will minimize the concentration of ozone, in contrary to the greater capacitance will increase the concentration of ozone. The ozone concentrations increase with augmenting of power. Maximum power is effective at DBD reactor spiral-cylinder is on the Dc = 20 mm, Dw = 1.2 mm, and the number of coil windings N = 10 loops with the resulting concentration is greater than 20 ppm and it consumes energy of 177.60 watts
Design of a multifiber light delivery system for photoacoustic-guided surgery.

PubMed

Eddins, Blackberrie; Bell, Muyinatu A Lediju

2017-04-01

This work explores light delivery optimization for photoacoustic-guided minimally invasive surgeries, such as the endonasal transsphenoidal approach. Monte Carlo simulations were employed to study three-dimensional light propagation in tissue, comprising one or two 4-mm diameter arteries located 3 mm below bone, an absorbing metallic drill contacting the bone surface, and a single light source placed next to the 2.4-mm diameter drill shaft with a 2.9-mm diameter spherical drill tip. The optimal fiber distance from the drill shaft was determined from the maximum normalized fluence to the underlying artery. Using this optimal fiber-to-drill shaft distance, Zemax simulations were employed to propagate Gaussian beams through one or more 600 micron-core diameter optical fibers for detection on the bone surface. When the number of equally spaced fibers surrounding the drill increased, a single merged optical profile formed with seven or more fibers, determined by thresholding the resulting light profile images at 1 / e times the maximum intensity. We used these simulations to inform design requirements, build a one to seven multifiber light delivery prototype to surround a surgical drill, and demonstrate its ability to simultaneously visualize the tool tip and blood vessel targets in the absence and presence of bone. The results and methodology are generalizable to multiple interventional photoacoustic applications.
Nonhuman Primate Ocular Biometry

PubMed Central

Augusteyn, Robert C.; Maceo Heilman, Bianca; Ho, Arthur; Parel, Jean-Marie

2016-01-01

Purpose To examine ocular growth in nonhuman primates (NHPs) from measurements on ex vivo eyes. Methods We obtained NHP eyes from animals that had been killed as part of other studies or because of health-related issues. Digital calipers were used to measure the horizontal, vertical, and anteroposterior globe diameters as well as corneal horizontal and vertical diameters of excised globes from 98 hamadryas baboons, 551 cynomolgus monkeys, and 112 rhesus monkeys, at ages ranging from 23 to 360 months. Isolated lens sagittal thickness and equatorial diameter were measured by shadowphotogrammetry. Wet and fixed dry weights were obtained for lenses. Results Nonhuman primate globe growth continues throughout life, slowing toward an asymptotic maximum. The final globe size scales with negative allometry to adult body size. Corneal growth ceases at around 20 months. Lens diameter increases but thickness decreases with increasing age. Nonhuman primate lens wet and dry weight accumulation is monophasic, continuing throughout life toward asymptotic maxima. The dry/wet weight ratio reaches a maximum of 0.33. Conclusions Nonhuman primate ocular globe and lens growth differ in several respects from those in humans. Although age-related losses of lens power and accommodative amplitude are similar, lens growth and properties are different indicating care should be taken in extrapolating NHP observations to the study of human accommodation. PMID:26780314
Design of a multifiber light delivery system for photoacoustic-guided surgery

NASA Astrophysics Data System (ADS)

Eddins, Blackberrie; Bell, Muyinatu A. Lediju

2017-04-01

This work explores light delivery optimization for photoacoustic-guided minimally invasive surgeries, such as the endonasal transsphenoidal approach. Monte Carlo simulations were employed to study three-dimensional light propagation in tissue, comprising one or two 4-mm diameter arteries located 3 mm below bone, an absorbing metallic drill contacting the bone surface, and a single light source placed next to the 2.4-mm diameter drill shaft with a 2.9-mm diameter spherical drill tip. The optimal fiber distance from the drill shaft was determined from the maximum normalized fluence to the underlying artery. Using this optimal fiber-to-drill shaft distance, Zemax simulations were employed to propagate Gaussian beams through one or more 600 micron-core diameter optical fibers for detection on the bone surface. When the number of equally spaced fibers surrounding the drill increased, a single merged optical profile formed with seven or more fibers, determined by thresholding the resulting light profile images at 1/e times the maximum intensity. We used these simulations to inform design requirements, build a one to seven multifiber light delivery prototype to surround a surgical drill, and demonstrate its ability to simultaneously visualize the tool tip and blood vessel targets in the absence and presence of bone. The results and methodology are generalizable to multiple interventional photoacoustic applications.
Hip-flexed postures do not affect local anaesthetic spread following induction of epidural analgesia for labour.

PubMed

Ducloy-Bouthors, A S; Davette, M; Le Fahler, G; Devos, P; Depret-Mosser, S; Krivosic-Horber, R

2004-04-01

Hip-flexed postures enlarging the pelvic diameter are used to improve the obstetric course of labour. Although most investigations show that lateral and sitting positions do not affect the spread of epidural analgesia, the effect of recently introduced hip-flexed postures has yet to be confirmed. This prospective randomised study included 93 parturients. Ropivacaine 0.1% 12 mL plus sufentanil 0.5 micrograms/mL was administered epidurally over a period of 6 min in one of four postures: sitting, right hip-flexed left lateral position, left hip-flexed right lateral position and supine 30 degrees lateral tilt as a control group. Left and right cephalad and sacral epidural spread were measured every 2 min over a period of 30 min. Pain relief, motor blockade and maternal and fetal side effects were noted. The total epidural spread was 15+/-0.3 dermatomes and the upper level of thermo-algesic blockade T7-T8 (range T3 to T10) in all groups. There were no differences between groups in left or right total spread or upper level of epidural blockade, time to maximal block or pain relief. There was no motor block nor any maternal or fetal side effects. The power of the study (1 - beta) was 93%. We conclude that, for the three hip-flexed postures tested, position does not influence local anaesthetic spread or symmetry of thermo-algesic blockade after induction of obstetric epidural analgesia.
Estimating tree crown widths for the primary Acadian species in Maine

Treesearch

Matthew B. Russell; Aaron R. Weiskittel

2012-01-01

In this analysis, data for seven conifer and eight hardwood species were gathered from across the state of Maine for estimating tree crown widths. Maximum and largest crown width equations were developed using tree diameter at breast height as the primary predicting variable. Quantile regression techniques were used to estimate the maximum crown width and a constrained...
Determining maximum stand density index in mixed species stands for strategic-scale stocking assessments

Treesearch

Chris W. Woodall; Patrick D. Miles; John S. Vissage

2005-01-01

Stand density index (SDI), although developed for use in even-aged monocultures, has been used for assessing stand density in large-scale forest inventories containing diverse tree species and size distributions. To improve application of SDI in unevenaged, mixed species stands present in large-scale forest inventories, trends in maximum SDI across diameter classes...
Microdosimetric investigation at the therapeutic proton beam facility of CATANA.

PubMed

De Nardo, L; Moro, D; Colautti, P; Conte, V; Tornielli, G; Cuttone, G

2004-01-01

Proton beams (62 Mev) are used by the Laboratori Nazionali del Sud of the Italian Institute of Nuclear Physics to treat eye melanoma tumours at the therapeutic facility called CATANA. A cylindrical slim tissue-equivalent proportional counter (TEPC) of 2.7 mm external diameter has been used to compare the radiation quality of two spread-out Bragg peaks (SOBP) at the CATANA proton beam.
Advanced Wavefront Sensor Concepts.

DTIC Science & Technology

1981-01-01

internal optics (a) Characteristics (see Figure 47) - Intensification with a 256 element linear self scanned diode array - Optical input; lenticular ...34 diameter - Lenticular array input to fiber optics which spread out to tubes - Photon counting for low noise fac- tor (b) Pe r fo rmance - Bialkali...problem in making the lenslet arrays in the pupil divider rectangular. The last optical elements are the lenticular lens arrays. In this group, the first
Reducing the spread of Phytophthora ramorum on the Redwood Nature Trail, Rogue River-Siskiyou National Forest, Curry County, Oregon: A Case Study

Treesearch

Ellen Michaels Goheen

2013-01-01

In late August 2009, a 20.3 cm (8 in) diameter tanoak (Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon & S.H. Oh) adjacent to a popular hiking trail on the Rogue River-Siskiyou National Forest was found infected with Phytophthora ramorum. The trail was immediately closed to the public. An eradication treatment...
Future directions in forest hydrology

Treesearch

T.M. Williams; Devendra Amatya; L. Bren; C. deJong; J.E. Nettles

2016-01-01

Forest hydrology is a separate and unique branch of hydrology due to the special conditions caused by trees, and the understorey beneath them, comprising a forest. Understanding the forest, with trees that can grow over 100 m tall, may have crowns up to 20-30 m in diameter with roots 5-10 m deep and spread as widely as the crowns, and have lifespans from 50 to 5000...
Assessment of sex in a modern Turkish population using cranial anthropometric parameters.

PubMed

Ekizoglu, Oguzhan; Hocaoglu, Elif; Inci, Ercan; Can, Ismail Ozgur; Solmaz, Dilek; Aksoy, Sema; Buran, Cudi Ferat; Sayin, Ibrahim

2016-07-01

The utilization of radiological imaging methods in anthropometric studies is being expanded by the application of modern imaging methods, leading to a decrease in costs, a decrease in the time required for analysis and the ability to create three-dimensional images. This retrospective study investigated 400 patients within the 18-45-years age group (mean age: 30.7±11.2years) using cranial computed tomography images. We measured 14 anthropometric parameters (basion-bregma height, basion-prosthion length, maximum cranial length and cranial base lengths, maximum cranial breadth, bizygomatic diameter, upper facial breadth, bimastoid diameter, orbital breadth, orbital length, biorbital breadth, interorbital breadth, foramen magnum breadth and foramen magnum length) of cranial measurements. The intra- and inter-observer repeatability and consistency were good. From the results of logistic regression analysis using morphometric measurements, the most conspicuous measurements in terms of dimorphism were maximum cranial length, bizygomatic diameter, basion-bregma height, and cranial base length. The most dimorphic structure was the bizygomatic diameter with an accuracy rate of 83% in females and 77% in males. In this study, 87.5% of females and 87.0% of males were classified accurately by this model including four parameters with a sensitivity of 91.5% and specificity of 85.0%. In conclusion, CT cranial morphometric analysis may be reliable for the assessment of sex in the Turkish population and is recommended for comparison of data of modern populations with those of former populations. Additionally, cranial morphometric data that we obtained from modern Turkish population may reveal population specific data, which may help current criminal investigations and identification of disaster victims. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Sonographic aorta/IVC cross-sectional area index for evaluation of dehydration in children.

PubMed

Kwon, Hyuksool; Jung, Jae Yun; Lee, Jin Hee; Kwak, Young Ho; Kim, Do Kyun; Jung, Jin Hee; Chang, Ik Wan; Kim, Kyuseok

2016-09-01

Current studies have not found sufficient evidence to encourage the use of ultrasound for assessing dehydration in children. We introduce a new sonographic parameter, the "aorta/inferior vena cava (IVC) cross-sectional area index" (Ao/IVCA) measured just inferior to the xiphoid process, for the effective evaluation of dehydration in children. This is a prospective, observational study. We enrolled children who presented to the pediatric emergency department (PED) between May 2014 and January 2015. We measured the maximum diameter of the aorta from inner wall to inner wall, and the long and short axis diameters of IVC using a convex array transducer. Ao/IVCA was calculated and compared with aorta/IVC maximal diameter index (Ao/IVCD) and the clinical dehydration scale (CDS). A total of 34 children were enrolled. We found a statistically significant correlation between Ao/IVCA and CDS (R(2) = 0.30; P <.001). Ao/IVCD did not correlate significantly with CDS (R(2) = 0.08; P =.11). The ability of Ao/IVCA and Ao/IVCD to predict CDS ≥1 was assessed using the receiver operating characteristic analysis. The area under the receiver operating characteristic curve for Ao/IVCA was larger than that for Ao/IVCD (0.87 vs 0.75, P= .04). The cut-off value of Ao/IVCA that yielded the maximum value of Youden index was 1.81 (sensitivity: 72%, specificity: 89%). Ao/IVCA might be a promising index for the assessment of dehydration. The diagnostic performance of Ao/IVCA for dehydration might be higher than that of the method that uses the maximum diameter of IVC and the aorta. Copyright © 2016 Elsevier Inc. All rights reserved.
[Evaluation of the diagnosis of subclinical endometritis in dairy cattle using ultrasound].

PubMed

Lenz, Mirjam; Drillich, Marc; Heuwieser, Wolfgang

2007-01-01

The aim of this study was to determine signs of subclinical endometritis found by ultrasound that are associated with reduced fertility in dairy cows. The maximum diameter of the uterine lumen was determined by ultrasound in 324 cows without clinical signs of endometritis after evaluation of the genital tract 21 to 27 days postpartum. Cows were classified into healthy or with subclinical endometritis by three threshold values for the maximum uterine lumen diameter of 0.2 cm, 0.5 cm or 0.8 cm. Examinations by rectal palpation and ultrasound as well as classifications were repeated 14 days later. In addition, ovaries were scanned by ultrasound to determine the stage of the estrous cycle. In a subgroup of 103 cows the echotexture of the uterus and its contents was evaluated. In these cows the diagnosis of subclinical endometritis was performed by a scoring system. The diameter of the uterine lumen was significantly affected by stage of the estrous cycle at the time of examination. However, no effects were found for the stage of the cycle at the time of examination on subsequent reproductive performance. A uterine lumen with a maximum diameter of more than 0.2 cm showed a significant negative association with conception rate and proportion of cows pregnant. Classification based on higher threshold values did not reveal an association with reproductive performance. Echogenic content in the uterus also decreased reproductive performance. A classification based on the echotexture of the uterus and its contents revealed significant differences between healthy cows and cows with subclinical endometritis regarding the proportion of cows inseminated and pregnant. The results of this study showed that the diagnostic of bovine endometritis should be broadend by ultrasonography. The definition of subclinical endometritis diagnosed by means of ultrasonography has to be evaluated in further studies.
The effect of aortic morphology on peri-operative mortality of ruptured abdominal aortic aneurysm.

PubMed

2015-06-01

To investigate whether aneurysm shape and extent, which indicate whether a patient with ruptured abdominal aortic aneurysm (rAAA) is eligible for endovascular repair (EVAR), influence the outcome of both EVAR and open surgical repair. The influence of six morphological parameters (maximum aortic diameter, aneurysm neck diameter, length and conicality, proximal neck angle, and maximum common iliac diameter) on mortality and reinterventions within 30 days was investigated in rAAA patients randomized before morphological assessment in the Immediate Management of the Patient with Rupture: Open Versus Endovascular strategies (IMPROVE) trial. Patients with a proven diagnosis of rAAA, who underwent repair and had their admission computerized tomography scan submitted to the core laboratory, were included. Among 458 patients (364 men, mean age 76 years), who had either EVAR (n = 177) or open repair (n = 281) started, there were 155 deaths and 88 re-interventions within 30 days of randomization analysed according to a pre-specified plan. The mean maximum aortic diameter was 8.6 cm. There were no substantial correlations between the six morphological variables. Aneurysm neck length was shorter in those undergoing open repair (vs. EVAR). Aneurysm neck length (mean 23.3, SD 16.1 mm) was inversely associated with mortality for open repair and overall: adjusted OR 0.72 (95% CI 0.57, 0.92) for each 16 mm (SD) increase in length. There were no convincing associations of morphological parameters with reinterventions. Short aneurysm necks adversely influence mortality after open repair of rAAA and preclude conventional EVAR. This may help explain why observational studies, but not randomized trials, have shown an early survival benefit for EVAR. ISRCTN 48334791. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

Development of the monitoring technique on the damage of piles using the biggest shaking table "E-defense"

NASA Astrophysics Data System (ADS)

Hayashi, Kazuhiro; Hachimori, Wataru; Kaneda, Shogo; Tamura, Shuji; Saito, Taiki

2017-10-01

In case of earthquake damage to buildings, the damage to a superstructure is visible, but the damage to a foundation structure, e.g. the underground pile, is difficult to detect. In this study, the authors aim to develop a monitoring technique for pile damage due to earthquakes. The world's biggest shaking table, E-Defense, was used to reproduce damage to RC pile models embedded in the soil inside a large scale shear box (8m in diameter and 6.5m in height). The diameter of the RC pile model was 154mm. It consisted of mortar (27.2N/mm2 in compressive strength), 6 main reinforcements (6.35mm in diameter) and shear reinforcement hard steel wire (2mm in diameter at intervals of 20mm). The natural period of the superstructure above the pile models is around 0.12sec. The soil consisted of 2 layers. The lower layer is Albany sand of 80% relative density while the upper layer is only 2m from the surface ground and is Kaketsu sand of 60% relative density. Primary four excitations were scaled from JMA Kobe waves in notification at different amplitudes. The maximum acceleration of each wave is 31gal, 67gal, 304gal, and 458gal, respectively. In the test result, reinforcing steels at the pile head of the RC model yielded when the maximum acceleration was 304gal. After that, mortar of the pile head peeled off and a bending shear failure occurred when the maximum acceleration was 458gal. The peak frequency of rotational spectrum on the foundation did not change in elastic range in the piles. However, the peak frequency fell after the plastic hinge occurred.
Fourier Domain Optical Coherence Tomography With 3D and En Face Imaging of the Punctum and Vertical Canaliculus: A Step Toward Establishing a Normative Database.

PubMed

Kamal, Saurabh; Ali, Mohammad Javed; Ali, Mohammad Hasnat; Naik, Milind N

2016-01-01

To report the features of Fourier domain optical coherence tomography imaging of the normal punctum and vertical canaliculus. Prospective, interventional series of consecutive healthy and asymptomatic adults, who volunteered for optical coherence tomography imaging, were included in the study. Fourier domain optical coherence tomography images of the punctum and vertical canaliculus along with 3D and En face images were captured using the RTVue scanner with a corneal adaptor module and a wide-angled lens. Maximum punctal diameter, mid-canalicular diameter, and vertical canalicular height were calculated. Statistical analysis was performed using Pearson correlation test, and scatter plot matrices were analyzed. A total of 103 puncta of 52 healthy subjects were studied. Although all the images could depict the punctum and vertical canaliculus and all the desired measurements could be obtained, occasional tear debris within the canaliculus was found to be interfering with the imaging. The mean maximum punctal diameter, mid-canalicular diameter, and vertical canalicular height were recorded as 214.71 ± 73 μm, 125.04 ± 60.69 μm, and 890.41 ± 154.76 μm, respectively, with an insignificant correlation between them. The maximum recorded vertical canalicular height in all the cases was far less than the widely reported depth of 2 mm. High-resolution 3D and En face images provided a detailed topography of punctal surface and overview of vertical canaliculus. Fourier domain optical coherence tomography with 3D and En face imaging is a useful noninvasive modality to image the proximal lacrimal system with consistently reproducible high-resolution images. This is likely to help clinicians in the management of proximal lacrimal disorders.
Pigments which reflect infrared radiation from fire

DOEpatents

Berdahl, Paul H.

1998-01-01

Conventional paints transmit or absorb most of the intense infrared (IR) radiation emitted by fire, causing them to contribute to the spread of fire. The present invention comprises a fire retardant paint additive that reflects the thermal IR radiation emitted by fire in the 1 to 20 micrometer (.mu.m) wavelength range. The important spectral ranges for fire control are typically about 1 to about 8 .mu.m or, for cool smoky fires, about 2 .mu.m to about 16 .mu.m. The improved inventive coatings reflect adverse electromagnetic energy and slow the spread of fire. Specific IR reflective pigments include titanium dioxide (rutile) and red iron oxide pigments with diameters of about 1 .mu.m to about 2 .mu.m and thin leafing aluminum flake pigments.
In-flight calibration of the Hitomi Soft X-ray Spectrometer. (2) Point spread function

NASA Astrophysics Data System (ADS)

Maeda, Yoshitomo; Sato, Toshiki; Hayashi, Takayuki; Iizuka, Ryo; Angelini, Lorella; Asai, Ryota; Furuzawa, Akihiro; Kelley, Richard; Koyama, Shu; Kurashima, Sho; Ishida, Manabu; Mori, Hideyuki; Nakaniwa, Nozomi; Okajima, Takashi; Serlemitsos, Peter J.; Tsujimoto, Masahiro; Yaqoob, Tahir

2018-03-01

We present results of inflight calibration of the point spread function of the Soft X-ray Telescope that focuses X-rays onto the pixel array of the Soft X-ray Spectrometer system. We make a full array image of a point-like source by extracting a pulsed component of the Crab nebula emission. Within the limited statistics afforded by an exposure time of only 6.9 ks and limited knowledge of the systematic uncertainties, we find that the raytracing model of 1 {^'.} 2 half-power-diameter is consistent with an image of the observed event distributions across pixels. The ratio between the Crab pulsar image and the raytracing shows scatter from pixel to pixel that is 40% or less in all except one pixel. The pixel-to-pixel ratio has a spread of 20%, on average, for the 15 edge pixels, with an averaged statistical error of 17% (1 σ). In the central 16 pixels, the corresponding ratio is 15% with an error of 6%.
Flour sodium dodecyl sulfate (SDS)-extractable protein level as a cookie flour quality indicator.

PubMed

Pareyt, Bram; Bruneel, Charlotte; Brijs, Kristof; Goesaert, Hans; Delcour, Jan A

2010-01-13

Flour characteristics of laboratory-milled flour fractions of two wheat cultivars were related to their cookie-baking performance. Cultivar (cv.) Albatros wheat milling yielded fractions with lower damaged starch (DS) and arabinoxylan levels and higher sodium dodecyl sulfate-extractable protein (SDSEP) levels than did cv. Meunier wheat milling. During baking, cv. Albatros flour doughs spread faster and set later than their cv. Meunier counterparts and, hence, resulted in larger cookie diameters. DS levels negatively affected spread rate during both cv. Albatros (R2=0.68) and cv. Meunier (R2=0.51) cookie baking. SDSEP levels also influenced cookie quality. The use of flour heat-treated to reduce its SDSEP levels to different degrees led to reduction of the set time (R2=0.90). It was deduced that larger gluten polymer sizes limit dough spread time during baking and that, apart from DS level, the SDSEP level is an indicator for cookie flour quality.
Formation of perched lava ponds on basaltic volcanoes: Interaction between cooling rate and flow geometry allows estimation of lava effusion rates

NASA Technical Reports Server (NTRS)

Wilson, L.; Parfitt, E. A.

1993-01-01

Perched lava ponds are infrequent but distinctive topographic features formed during some basaltic eruptions. Two such ponds, each approximately 150 m in diameter, formed during the 1968 eruption at Napau Crater and the 1974 eruption of Mauna Ulu, both on Kilauea Volcano, Hawaii. Each one formed where a channelized, high volume flux lava flow encountered a sharp reduction of slope: the flow spread out radially and stalled, forming a well-defined terminal levee enclosing a nearly circular lava pond. We describe a model of how cooling limits the motion of lava spreading radially into a pond and compare this with the case of a channelized flow. The difference in geometry has a major effect, such that the size of a pond is a good indicator of the volume flux of the lava forming it. Lateral spreading on distal shallow slopes is a major factor limiting the lengths of lava flows.
The starting transient of solid propellant rocket motors with high internal gas velocities. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Peretz, A.; Caveny, L. H.; Kuo, K. K.; Summerfield, M.

1973-01-01

A comprehensive analytical model which considers time and space development of the flow field in solid propellant rocket motors with high volumetric loading density is described. The gas dynamics in the motor chamber is governed by a set of hyperbolic partial differential equations, that are coupled with the ignition and flame spreading events, and with the axial variation of mass addition. The flame spreading rate is calculated by successive heating-to-ignition along the propellant surface. Experimental diagnostic studies have been performed with a rectangular window motor (50 cm grain length, 5 cm burning perimeter and 1 cm hydraulic port diameter), using a controllable head-end gaseous igniter. Tests were conducted with AP composite propellant at port-to-throat area ratios of 2.0, 1.5, 1.2, and 1.06, and head-end pressures from 35 to 70 atm. Calculated pressure transients and flame spreading rates are in very good agreement with those measured in the experimental system.
Effect of conductivity and concentration on the sample stream in the transverse axis of a continuous flow electrophoresis chamber

NASA Technical Reports Server (NTRS)

Miller, Teresa Y.; Williams, George O.; Snyder, Robert S.

1985-01-01

The resolution of continuous flow electrophoresis systems is generally measured by the spread of the sample bands in the direction of the electrophoretic migration. This paper evaluates the cross section of the sample bands in the plane perpendicular to the flow and shows that the spread in the direction perpendicular to the migration increased significantly with the applied electric field. Concentrated samples of monodisperse latex particles and vinyltoluene T-butylstyrene particles in sample buffers of different electrical conductivities were used to map the shape of the sample bands relative to the zero electric field case. As the electric field was applied, the sample band spread from an initial diameter of only one-third the chamber thickness until it approached the chamber walls where electroosmosis significantly reduced the resolution of separation. It can be shown, however, that it is possible to minimize these distortions by careful sample preparation and experiment design.
Image processing analysis of nuclear track parameters for CR-39 detector irradiated by thermal neutron

NASA Astrophysics Data System (ADS)

Al-Jobouri, Hussain A.; Rajab, Mustafa Y.

2016-03-01

CR-39 detector which covered with boric acid (H3Bo3) pellet was irradiated by thermal neutrons from (241Am - 9Be) source with activity 12Ci and neutron flux 105 n. cm-2. s-1. The irradiation times -TD for detector were 4h, 8h, 16h and 24h. Chemical etching solution for detector was sodium hydroxide NaOH, 6.25N with 45 min etching time and 60 C˚ temperature. Images of CR-39 detector after chemical etching were taken from digital camera which connected from optical microscope. MATLAB software version 7.0 was used to image processing. The outputs of image processing of MATLAB software were analyzed and found the following relationships: (a) The irradiation time -TD has behavior linear relationships with following nuclear track parameters: i) total track number - NT ii) maximum track number - MRD (relative to track diameter - DT) at response region range 2.5 µm to 4 µm iii) maximum track number - MD (without depending on track diameter - DT). (b) The irradiation time -TD has behavior logarithmic relationship with maximum track number - MA (without depending on track area - AT). The image processing technique principally track diameter - DT can be take into account to classification of α-particle emitters, In addition to the contribution of these technique in preparation of nano- filters and nano-membrane in nanotechnology fields.
Electrospun Poly(lactic acid-co-glycolic acid) Scaffolds for Skin Tissue Engineering

PubMed Central

Kumbar, Sangamesh G.; Nukavarapu, Syam Prasad; James, Roshan; Nair, Lakshmi S.; Laurencin, Cato T.

2008-01-01

Electrospun fiber matrices composed of scaffolds of varying fiber diameters were investigated for potential application of severe skin loss. Few systematic studies have been performed to examine the effect of varying fiber diameter electrospun fiber matrices for skin regeneration. The present study reports the fabrication of poly[lactic acid-co-glycolic acid] (PLAGA) matrices with fiber diameters of 150–225, 200–300, 250–467, 500–900, 600–1200, 2500–3000 and 3250–6000 nm via electrospinning. All fiber matrices found to have a tensile modulus from 39.23 ± 8.15 to 79.21 ± 13.71 MPa which falls in the range for normal human skin. Further, the porous fiber matrices have porosity between 38–60 % and average pore diameters between 10–14µm. We evaluated the efficacy of these biodegradable fiber matrices as skin substitutes by seeding them with human skin fibroblasts (hSF). Human skin fibroblasts acquired a well spread morphology and showed significant progressive growth on fiber matrices in the 350–1100 nm diameter range. Collagen type III gene expression was significantly up-regulated in hSF seeded on matrices with fiber diameters in the range of 350–1100 nm. Based on the need, the proposed fiber skin substitutes can be successfully fabricated and optimized for skin fibroblast attachment and growth. PMID:18639927
Assessment of penetrating thermal tissue damage/spread associated with PhotonBlade™, Valleylab™ Pencil, Valleylab™ EDGE™ Coated Pencil, PlasmaBlade® 3.0S and PlasmaBlade® 4.0 for intraoperative tissue dissection using the fresh extirpated porcine muscle model

NASA Astrophysics Data System (ADS)

Bennett, Haydon E.; Taylor, Scott D.; Fugett, James H.; Shrout, Joshua L.; Davison, Paul O.; Ryan, S. Eric; Coad, James E.

2017-02-01

Penetrating thermal tissue damage/spread is an important aspect of many electrosurgical devices and correlates with effective tissue cutting, hemostasis, preservation of adjacent critical structures and tissue healing. This study compared the thermal damage/spread associated with the PhotonBlade, Valleylab Pencil, Valleylab EDGE Coated Pencil, PlasmaBlade 3.0S and PlasmaBlade 4.0, when performing a single pass dynamic tissue cut in fresh extirpated porcine longissimus muscle. These devices were used in a fashion that emulated their use in the clinical setting. Each device's thermal damage/spread, at Minimum, Median and Maximum power input settings, was assessed with nitroblue tetrazolium viability staining in the WVU Pathology Laboratory for Translational Medicine. The thermal damage/spread associated with the PhotonBlade was compared with the other devices tested based on the individual treatment results (n=179 cuts combined). In summary, the PhotonBlade overall demonstrated the least penetrating thermal tissue damage/spread, followed by the PlasmaBlade 4.0, then Valleylab Pencil and PlasmaBlade 3.0S and then Valleylab EDGE Coated Pencil in order of increasing thermal damage/spread depths.
Fast and accurate detection of spread source in large complex networks.

PubMed

Paluch, Robert; Lu, Xiaoyan; Suchecki, Krzysztof; Szymański, Bolesław K; Hołyst, Janusz A

2018-02-06

Spread over complex networks is a ubiquitous process with increasingly wide applications. Locating spread sources is often important, e.g. finding the patient one in epidemics, or source of rumor spreading in social network. Pinto, Thiran and Vetterli introduced an algorithm (PTVA) to solve the important case of this problem in which a limited set of nodes act as observers and report times at which the spread reached them. PTVA uses all observers to find a solution. Here we propose a new approach in which observers with low quality information (i.e. with large spread encounter times) are ignored and potential sources are selected based on the likelihood gradient from high quality observers. The original complexity of PTVA is O(N α ), where α ∈ (3,4) depends on the network topology and number of observers (N denotes the number of nodes in the network). Our Gradient Maximum Likelihood Algorithm (GMLA) reduces this complexity to O (N 2 log (N)). Extensive numerical tests performed on synthetic networks and real Gnutella network with limitation that id's of spreaders are unknown to observers demonstrate that for scale-free networks with such limitation GMLA yields higher quality localization results than PTVA does.
Blind Deconvolution of Astronomical Images with a Constraint on Bandwidth Determined by the Parameters of the Optical System

NASA Astrophysics Data System (ADS)

Luo, Lin; Fan, Min; Shen, Mang-zuo

2008-01-01

Atmospheric turbulence severely restricts the spatial resolution of astronomical images obtained by a large ground-based telescope. In order to reduce effectively this effect, we propose a method of blind deconvolution, with a bandwidth constraint determined by the parameters of the telescope's optical system based on the principle of maximum likelihood estimation, in which the convolution error function is minimized by using the conjugate gradient algorithm. A relation between the parameters of the telescope optical system and the image's frequency-domain bandwidth is established, and the speed of convergence of the algorithm is improved by using the positivity constraint on the variables and the limited-bandwidth constraint on the point spread function. To avoid the effective Fourier frequencies exceed the cut-off frequency, it is required that each single image element (e.g., the pixel in the CCD imaging) in the sampling focal plane should be smaller than one fourth of the diameter of the diffraction spot. In the algorithm, no object-centered constraint was used, so the proposed method is suitable for the image restoration of a whole field of objects. By the computer simulation and by the restoration of an actually-observed image of α Piscium, the effectiveness of the proposed method is demonstrated.
Comparison of simulated and measured nonlinear ultrasound fields

NASA Astrophysics Data System (ADS)

Du, Yigang; Jensen, Henrik; Jensen, Jørgen Arendt

2011-03-01

In this paper results from a non-linear AS (angular spectrum) based ultrasound simulation program are compared to water-tank measurements. A circular concave transducer with a diameter of 1 inch (25.4 mm) is used as the emitting source. The measured pulses are first compared with the linear simulation program Field II, which will be used to generate the source for the AS simulation. The generated non-linear ultrasound field is measured by a hydrophone in the focal plane. The second harmonic component from the measurement is compared with the AS simulation, which is used to calculate both fundamental and second harmonic fields. The focused piston transducer with a center frequency of 5 MHz is excited by a waveform generator emitting a 6-cycle sine wave. The hydrophone is mounted in the focal plane 118 mm from the transducer. The point spread functions at the focal depth from Field II and measurements are illustrated. The FWHM (full width at half maximum) values are 1.96 mm for the measurement and 1.84 mm for the Field II simulation. The fundamental and second harmonic components of the experimental results are plotted compared with the AS simulations. The RMS (root mean square) errors of the AS simulations are 7.19% and 10.3% compared with the fundamental and second harmonic components of the measurements.
Numerical study of droplet impact and rebound on superhydrophobic surface

NASA Astrophysics Data System (ADS)

Cai, Xuan; Wu, Yanchen; Woerner, Martin; Frohnapfel, Bettina

2017-11-01

Droplet impact and rebound on superhydrophobic surface is an important process in many applications; among them are developing self-cleaning or anti-icing materials and limiting liquid film formation of Diesel Exhaust Fluid (DEF) in exhaust gas pipe. In the latter field, rebound of DEF droplet from wall is desired as an effective mean for avoiding or reducing unwanted solid deposition. Our goal is to numerically study influence of surface wettability on DEF droplet impact and rebound behavior. A phase-field method is chosen, which was implemented in OpenFOAM by us and validated for wetting-related interfacial flow problems. In the present contribution we first numerically reproduce relevant experimental studies in literature, to validate the code for droplet impact and rebound problem. There we study droplet-surface contact time, maximum/instantaneous spreading factor and droplet shape evolution. Our numerical results show good agreement with experimental data. Next we investigate for DEF droplets the effects of diameter, impact velocity and surface wettability on rebound behavior and jumping height. Based on Weber number and equilibrium contact angle, two regimes are identified. We show that surface wettability is a deciding factor for achieving rebound event. This work is supported by Foundation ``Friedrich-und-Elisabeth Boysen Stiftung fuer Forschung und Innovation'' (BOY-127-TP1).
Theoretical analysis for condensation heat transfer of binary refrigerant mixtures with annular flow in horizontal mini-tubes

NASA Astrophysics Data System (ADS)

Zhang, Hui-Yong; Li, Jun-Ming; Sun, Ji-Liang; Wang, Bu-Xuan

2016-01-01

A theoretical model is developed for condensation heat transfer of binary refrigerant mixtures in mini-tubes with diameter about 1.0 mm. Condensation heat transfer of R410A and R32/R134a mixtures at different mass fluxes and saturated temperatures are analyzed, assuming that the phase flow pattern is annular flow. The results indicate that there exists a maximum interface temperature at the beginning of condensation process for azeotropic and zeotropic mixtures and the corresponding vapor quality to the maximum value increases with mass flux. The effects of mass flux, heat flux, surface tension and tube diameter are analyzed. As expected, the condensation heat transfer coefficients increase with mass flux and vapor quality, and increase faster in high vapor quality region. It is found that the effects of heat flux and surface tension are not so obvious as that of tube diameter. The characteristics of condensation heat transfer of zeotropic mixtures are consistent to those of azeotropic refrigerant mixtures. The condensation heat transfer coefficients increase with the concentration of the less volatile component in binary mixtures.
Why is CDMA the solution for mobile satellite communication

NASA Technical Reports Server (NTRS)

Gilhousen, Klein S.; Jacobs, Irwin M.; Padovani, Roberto; Weaver, Lindsay A.

1989-01-01

It is demonstrated that spread spectrum Code Division Multiple Access (CDMA) systems provide an economically superior solution to satellite mobile communications by increasing the system maximum capacity with respect to single channel per carrier Frequency Division Multiple Access (FDMA) systems. Following the comparative analysis of CDMA and FDMA systems, the design of a model that was developed to test the feasibility of the approach and the performance of a spread spectrum system in a mobile environment. Results of extensive computer simulations as well as laboratory and field tests results are presented.
Mean flow characteristics for the oblique impingement of an axisymmetric jet

NASA Technical Reports Server (NTRS)

Foss, J. F.; Kleis, S. J.

1975-01-01

The oblique impingement of an axisymmetric jet has been investigated. A summary of the data and the analytical interpretations of the dominant mechanisms which influence the flow are reported. The major characteristics of the shallow angle oblique jet impingement flow field are: (1) minimal dynamic spreading as revealed by the surface pressure field, (2) pronounced kinematic spreading as revealed by the jet flow velocity field, (3) a pronounced upstream shift of the stagnation point from the maximum pressure point, (4) the production of streamwise vorticity by the impingement process.
Biometrical analysis of the shoulder joint regarding glenoid implant dimensions for arthroplasty.

PubMed

Kircher, Jörn; Bittersohl, Bernd; Zilkens, Christoph; Hedtmann, Achim; Krauspe, Rüdiger

2014-05-01

Reduced bone stock and difficult intraoperative orientation are challenges in glenoid replacement surgery. New implant designs and methods for fixation, such as locking screws, extra-long central pegs and/or central compression screws are targeting these issues. The objective of this study is the analysis of the glenoid dimension regarding maximum central peg diameter and peg length (PL), and maximum screw length (SL) for glenoid fixation. Retrospective analysis of magnetic resonance imaging (n = 50) scans. Measurement of the maximum inferior glenoid diameter (GD), SL, maximum length of a 9.9, 10 and 11.4 mm central peg (PL) in the transverse plane; glenoid version (GV), humeral head diameter (HHD). Two independent measurements. Mean age: 49.0 ± 15.7 years (17-80) (n = 20 female, 49.6 ± 16.0; n = 30 male, 48.6 ± 15.7). Mean values of measurement were GD: 28.9 ± 3.7 mm (21-39); SL: 34.1 ± 4.9 mm (26-44); PL 9.9 mm: 19.4 ± 4.3 mm (9-30); PL 10 mm: 19.0 ± 4.4 mm (8-30); PL 11.4 mm: 16.5 ± 4.1 mm (7-26) with significant gender differences (p = 0.001; p = 0.022; p = 0.001); GV: -0.6° ± 4.9° (-10 to 11); HHD: 50.0 mm ± 4.9 (41-61). There was good correlation between PL and SL (r = 0.32, p = 0.024) and for GD and PL (r = 0.61, p = 0.001; r = 0.57, p = 0.001; r = 0.96, p = 0.001). The ratio of HHD and GD was very constant with 0.6 ± 0.07. These data indicate the high interindividual variability of glenoid morphology including significant gender-related differences. The good correlation between humeral head size and GD and maximum central PL can be helpful for cases with reduced bone stock in decision-making about implant size and bone grafting.
Craters formed in mineral dust by hypervelocity microparticles.

NASA Technical Reports Server (NTRS)

Vedder, J. F.

1972-01-01

As a simulation of erosion processes on the lunar surface, impact craters were formed in dust targets by 2- to 5-micron-diameter polystyrene spheres with velocities between 2.5 and 12 km/sec. For weakly cohesive, thick targets of basalt dust with a maximum grain size comparable to the projectile diameter, the craters had an average projectile-to-diameter diameter ratio of 25, and the displaced mass was 3 orders of magnitude greater than the projectile mass. In a simulation of the effect of a dust covering on lunar rocks, a layer of cohesive, fine-grained basalt dust with a thickness nearly twice the projectile diameter protected a glass substrate from damage, but an area about 50 times the cross-sectional area of the projectile was cleared of all but a few grains. Impact damage was produced in glass under a thinner dust layer.

Spherulitic crystallization of aspartame from aqueous solution in a two-dimensional cell

NASA Astrophysics Data System (ADS)

Mori, Tetsushi; Kubota, Noriaki; Abe, Sou; Kishimoto, Shin'ichi; Kumon, Satoshi; Naruse, Masayoshi

1993-10-01

An artificial sweetener, aspartame (α-L-aspartyl-L-phenylalanine methyl aster) was crystallized as spherulites in the order of magnitude of centimeters in radius. With increasing relative supersaturation σ, the number of nucleation sites increased, but the radius of the largest spherulite in the cell decreased. The growth rate G of the spherulite was 1-2 mm/min and is given as a function of σ by the experimental equation: G= 8.45 x 10 -2 σ 1.95. Individual fiber crystals of the spherulite grew slowly in the diameter direction until a critical diameter (10 μm or so) was attained. Longitudinally, however, they grew fast. They repeatedly split and branched during growth, spreading radially to form spherulites.
Gold nanoparticle induced vasculature damage in radiotherapy: Comparing protons, megavoltage photons, and kilovoltage photons

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

Lin, Yuting, E-mail: yutingl188@gmail.com; Paganetti, Harald; Schuemann, Jan

2015-10-15

Purpose: The purpose of this work is to investigate the radiosensitizing effect of gold nanoparticle (GNP) induced vasculature damage for proton, megavoltage (MV) photon, and kilovoltage (kV) photon irradiation. Methods: Monte Carlo simulations were carried out using tool for particle simulation (TOPAS) to obtain the spatial dose distribution in close proximity up to 20 μm from the GNPs. The spatial dose distribution from GNPs was used as an input to calculate the dose deposited to the blood vessels. GNP induced vasculature damage was evaluated for three particle sources (a clinical spread out Bragg peak proton beam, a 6 MV photonmore » beam, and two kV photon beams). For each particle source, various depths in tissue, GNP sizes (2, 10, and 20 nm diameter), and vessel diameters (8, 14, and 20 μm) were investigated. Two GNP distributions in lumen were considered, either homogeneously distributed in the vessel or attached to the inner wall of the vessel. Doses of 30 Gy and 2 Gy were considered, representing typical in vivo enhancement studies and conventional clinical fractionation, respectively. Results: These simulations showed that for 20 Au-mg/g GNP blood concentration homogeneously distributed in the vessel, the additional dose at the inner vascular wall encircling the lumen was 43% of the prescribed dose at the depth of treatment for the 250 kVp photon source, 1% for the 6 MV photon source, and 0.1% for the proton beam. For kV photons, GNPs caused 15% more dose in the vascular wall for 150 kVp source than for 250 kVp. For 6 MV photons, GNPs caused 0.2% more dose in the vascular wall at 20 cm depth in water as compared to at depth of maximum dose (Dmax). For proton therapy, GNPs caused the same dose in the vascular wall for all depths across the spread out Bragg peak with 12.7 cm range and 7 cm modulation. For the same weight of GNPs in the vessel, 2 nm diameter GNPs caused three times more damage to the vessel than 20 nm diameter GNPs. When the GNPs were attached to the inner vascular wall, the damage to the inner vascular wall can be up to 207% of the prescribed dose for the 250 kVp photon source, 4% for the 6 MV photon source, and 2% for the proton beam. Even though the average dose increase from the proton beam and MV photon beam was not large, there were high dose spikes that elevate the local dose of the parts of the blood vessel to be higher than 15 Gy even for 2 Gy prescribed dose, especially when the GNPs can be actively targeted to the endothelial cells. Conclusions: GNPs can potentially be used to enhance radiation therapy by causing vasculature damage through high dose spikes caused by the addition of GNPs especially for hypofractionated treatment. If GNPs are designed to actively accumulate at the tumor vasculature walls, vasculature damage can be increased significantly. The largest enhancement is seen using kilovoltage photons due to the photoelectric effect. Although no significant average dose enhancement was observed for the whole vasculature structure for both MV photons and protons, they can cause high local dose escalation (>15 Gy) to areas of the blood vessel that can potentially contribute to the disruption of the functionality of the blood vessels in the tumor.« less
Gold nanoparticle induced vasculature damage in radiotherapy: Comparing protons, megavoltage photons, and kilovoltage photons.

PubMed

Lin, Yuting; Paganetti, Harald; McMahon, Stephen J; Schuemann, Jan

2015-10-01

The purpose of this work is to investigate the radiosensitizing effect of gold nanoparticle (GNP) induced vasculature damage for proton, megavoltage (MV) photon, and kilovoltage (kV) photon irradiation. Monte Carlo simulations were carried out using tool for particle simulation (TOPAS) to obtain the spatial dose distribution in close proximity up to 20 μm from the GNPs. The spatial dose distribution from GNPs was used as an input to calculate the dose deposited to the blood vessels. GNP induced vasculature damage was evaluated for three particle sources (a clinical spread out Bragg peak proton beam, a 6 MV photon beam, and two kV photon beams). For each particle source, various depths in tissue, GNP sizes (2, 10, and 20 nm diameter), and vessel diameters (8, 14, and 20 μm) were investigated. Two GNP distributions in lumen were considered, either homogeneously distributed in the vessel or attached to the inner wall of the vessel. Doses of 30 Gy and 2 Gy were considered, representing typical in vivo enhancement studies and conventional clinical fractionation, respectively. These simulations showed that for 20 Au-mg/g GNP blood concentration homogeneously distributed in the vessel, the additional dose at the inner vascular wall encircling the lumen was 43% of the prescribed dose at the depth of treatment for the 250 kVp photon source, 1% for the 6 MV photon source, and 0.1% for the proton beam. For kV photons, GNPs caused 15% more dose in the vascular wall for 150 kVp source than for 250 kVp. For 6 MV photons, GNPs caused 0.2% more dose in the vascular wall at 20 cm depth in water as compared to at depth of maximum dose (Dmax). For proton therapy, GNPs caused the same dose in the vascular wall for all depths across the spread out Bragg peak with 12.7 cm range and 7 cm modulation. For the same weight of GNPs in the vessel, 2 nm diameter GNPs caused three times more damage to the vessel than 20 nm diameter GNPs. When the GNPs were attached to the inner vascular wall, the damage to the inner vascular wall can be up to 207% of the prescribed dose for the 250 kVp photon source, 4% for the 6 MV photon source, and 2% for the proton beam. Even though the average dose increase from the proton beam and MV photon beam was not large, there were high dose spikes that elevate the local dose of the parts of the blood vessel to be higher than 15 Gy even for 2 Gy prescribed dose, especially when the GNPs can be actively targeted to the endothelial cells. GNPs can potentially be used to enhance radiation therapy by causing vasculature damage through high dose spikes caused by the addition of GNPs especially for hypofractionated treatment. If GNPs are designed to actively accumulate at the tumor vasculature walls, vasculature damage can be increased significantly. The largest enhancement is seen using kilovoltage photons due to the photoelectric effect. Although no significant average dose enhancement was observed for the whole vasculature structure for both MV photons and protons, they can cause high local dose escalation (>15 Gy) to areas of the blood vessel that can potentially contribute to the disruption of the functionality of the blood vessels in the tumor.
Gold nanoparticle induced vasculature damage in radiotherapy: Comparing protons, megavoltage photons, and kilovoltage photons

PubMed Central

Lin, Yuting; Paganetti, Harald; McMahon, Stephen J.; Schuemann, Jan

2015-01-01

Purpose: The purpose of this work is to investigate the radiosensitizing effect of gold nanoparticle (GNP) induced vasculature damage for proton, megavoltage (MV) photon, and kilovoltage (kV) photon irradiation. Methods: Monte Carlo simulations were carried out using tool for particle simulation (TOPAS) to obtain the spatial dose distribution in close proximity up to 20 μm from the GNPs. The spatial dose distribution from GNPs was used as an input to calculate the dose deposited to the blood vessels. GNP induced vasculature damage was evaluated for three particle sources (a clinical spread out Bragg peak proton beam, a 6 MV photon beam, and two kV photon beams). For each particle source, various depths in tissue, GNP sizes (2, 10, and 20 nm diameter), and vessel diameters (8, 14, and 20 μm) were investigated. Two GNP distributions in lumen were considered, either homogeneously distributed in the vessel or attached to the inner wall of the vessel. Doses of 30 Gy and 2 Gy were considered, representing typical in vivo enhancement studies and conventional clinical fractionation, respectively. Results: These simulations showed that for 20 Au-mg/g GNP blood concentration homogeneously distributed in the vessel, the additional dose at the inner vascular wall encircling the lumen was 43% of the prescribed dose at the depth of treatment for the 250 kVp photon source, 1% for the 6 MV photon source, and 0.1% for the proton beam. For kV photons, GNPs caused 15% more dose in the vascular wall for 150 kVp source than for 250 kVp. For 6 MV photons, GNPs caused 0.2% more dose in the vascular wall at 20 cm depth in water as compared to at depth of maximum dose (Dmax). For proton therapy, GNPs caused the same dose in the vascular wall for all depths across the spread out Bragg peak with 12.7 cm range and 7 cm modulation. For the same weight of GNPs in the vessel, 2 nm diameter GNPs caused three times more damage to the vessel than 20 nm diameter GNPs. When the GNPs were attached to the inner vascular wall, the damage to the inner vascular wall can be up to 207% of the prescribed dose for the 250 kVp photon source, 4% for the 6 MV photon source, and 2% for the proton beam. Even though the average dose increase from the proton beam and MV photon beam was not large, there were high dose spikes that elevate the local dose of the parts of the blood vessel to be higher than 15 Gy even for 2 Gy prescribed dose, especially when the GNPs can be actively targeted to the endothelial cells. Conclusions: GNPs can potentially be used to enhance radiation therapy by causing vasculature damage through high dose spikes caused by the addition of GNPs especially for hypofractionated treatment. If GNPs are designed to actively accumulate at the tumor vasculature walls, vasculature damage can be increased significantly. The largest enhancement is seen using kilovoltage photons due to the photoelectric effect. Although no significant average dose enhancement was observed for the whole vasculature structure for both MV photons and protons, they can cause high local dose escalation (>15 Gy) to areas of the blood vessel that can potentially contribute to the disruption of the functionality of the blood vessels in the tumor. PMID:26429263
Is There a Maximum Size of Water Drops in Nature?

ERIC Educational Resources Information Center

Vollmer, Michael; Mollmann, Klaus-Peter

2013-01-01

In nature, water drops can have a large variety of sizes and shapes. Small droplets with diameters of the order of 5 to 10 µm are present in fog and clouds. This is not sufficiently large for gravity to dominate their behavior. In contrast, raindrops typically have sizes of the order of 1 mm, with observed maximum sizes in nature of around 5 mm in…
Relative maxima of diameter and basal area

Treesearch

Thomas B. Lynch; Difei Zhang

2012-01-01

It has often been observed that maximum dbh growth occurs at an earlier age than maximum individual tree basal area growth. This can be deduced from the geometry of the tree stem, by observing that a dbh increment at a given radius will be associated with a larger basal area increment than an equal dbh increment occurring at a shorter radius from the stem center. Thus...
PROFIT-PC: a program for estimating maximum net revenue from multiproduct harvests in Appalachian hardwoods

Treesearch

Chris B. LeDoux; John E. Baumgras; R. Bryan Selbe

1989-01-01

PROFIT-PC is a menu driven, interactive PC (personal computer) program that estimates optimum product mix and maximum net harvesting revenue based on projected product yields and stump-to-mill timber harvesting costs. Required inputs include the number of trees/acre by species and 2 inches diameter at breast-height class, delivered product prices by species and product...
The effect of different temperature profiles upon the length and crystallinity of vertically-aligned multi-walled carbon nanotubes.

PubMed

Yun, Jongju; Lee, Cheesung; Zheng, Qing; Baik, Seunghyun

2012-08-01

We synthesized vertically-aligned multi-walled carbon nanotubes with an inner diameter of 1.6-7.5 nm and stack height of 80-28600 microm by chemical vapor deposition. The effects of synthesis conditions such as substrate position in the tube furnace, maximum temperature, temperature increasing rate and synthesis duration on the structure of nanotubes were investigated. It was found that slightly faster temperature increase rate resulted in significantly longer length, larger diameter and more defects of nanotubes. Structural parameters such as inner, outer diameters, wall thickness and defects were investigated using transmission electron microscopy and Raman spectroscopy.
Burnout current density of bismuth nanowires

NASA Astrophysics Data System (ADS)

Cornelius, T. W.; Picht, O.; Müller, S.; Neumann, R.; Völklein, F.; Karim, S.; Duan, J. L.

2008-05-01

Single bismuth nanowires with diameters ranging from 100nmto1μm were electrochemically deposited in ion track-etched single-pore polycarbonate membranes. The maximum current density the wires are able to carry was investigated by ramping up the current until failure occurred. It increases by three to four orders of magnitude for nanowires embedded in the template compared to bulk bismuth and rises with diminishing diameter. Simulations show that the wires are heated up electrically to the melting temperature. Since the surface-to-volume ratio rises with diminishing diameter, thinner wires dissipate the heat more efficiently to the surrounding polymer matrix and, thus, can tolerate larger current densities.
Experiments on Spray from a Rolling Tire

NASA Astrophysics Data System (ADS)

Radovich, Charles; Browand, Fred

2010-11-01

A novel laboratory apparatus has been built to understand the mechanisms and statistics of droplet production for spray emerging from a rolling tire. Using high-speed imaging, water passing through a single circumferential groove was observed to leave the tire contact patch in the form of a liquid sheet of non-uniform thickness. The sheet breaks into droplets as a result of several, organized instabilities. Measurements for the breakup length of the liquid sheet showed a dependence on Weber number proportional to We-1/6, for Weber numbers of 2700, 10900 and 24400. A technique to identify and size water droplets was developed and the distribution of droplet sizes was determined as a function of Weber number. At We = 2700, droplet sizes between 80 and 9000μm were detected, with a mean diameter near 800μm. Both the range of droplet sizes and the mean diameter were found to decrease with increasing Weber number as (approximately) We-1/2. Correlation Image Velocimetry (CIV) was used to estimate the distribution of droplet velocities as a function of droplet size. The spread of droplet velocities about the tire peripheral speed is strongly correlated with droplet size. The spread can be estimated by a simple physical model incorporating rigid droplets subject to gravity and drag.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Bochong; Kubota, Hitoshi, E-mail: hit-kubota@aist.go.jp; Yakushiji, Kay

The dependence on diameter of the emission power in MgO-based nano-pillar spin torque oscillators (STOs) was systematically investigated. A maximum emission power of over 2.5 μW was obtained around 300 nm in diameter, which is the largest reported to date among the out-of-plane precession STOs. By analyzing physical quantities, precession cone angle of the free-layer magnetization was evaluated. In the diameter range below 300 nm, the increase in power was mainly due to the increase of the injected current. The power decrease above 300 nm is possibly attributed to the decrease in the averaged precession cone angle, suggesting spatial phase difference of magnetization precession.more » This study provides the method for estimating the optimum STO diameter, which is of great importance in practical use.« less
Network structure control of binary mixed langmuir monolayers of homo-PS and PS-b-P2VP.

PubMed

Wen, Gangyao

2010-03-25

Our recent work showed there existed a composition window for mixed Langmuir monolayers of homopolystyrene (h-PS) and a symmetric diblock copolymer polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) to form necklace-network structures at the air/water interface. In order to study further the possible mechanism and control the network structure (i.e., surface coverage and nanoaggregate diameter), effects of spreading solution concentration and volume, subphase temperature, and transfer pressure on the network structure were studied by the Langmuir monolayer technique and tapping mode atomic force microscopy. With the increase of transfer pressure, there existed a novel nonlinear behavior for the nanoaggregate diameter first to increase, then to decrease, and finally to increase again, while the surface coverage tended to increase step by step. Moreover, with the elevation of temperature, chain motion between the adjoining nanoaggregates tended to be improved and thus the nanoaggregate diameter tended to be more uniform.
Foramen arcuale: a rare morphological variation located in atlas vertebrae.

PubMed

Cirpan, Sibel; Yonguc, Goksin Nilufer; Edizer, Mete; Mas, Nuket Gocmen; Magden, A Orhan

2017-08-01

To investigate the incidence of foramen arcuale in dry atlas vertebrae which may cause clinical problems. Eighty-one dry human cervical vertebrae were examined. The evaluated parameters of two atlas vertebrae including foramen arcuale were as follows: maximum antero-posterior, transverse diameters and areas of the right and left superior articular facets and transverse foramina; maximum antero-posterior diameters, heights, areas and central sagittal thickness of bony arch forming roof of foramen arcuale, respectively. All parameters were measured with caliper in milimeters. Thirteen of eighty-one cervical vertebrae specimens (13/81, 16.05%) were atlas and the two of thirteen atlas vertebrae (2/13, 15.38%) had macroscopically complete foramen arcuale. Each of the two atlas vertebrae was including one foramen arcuale (one on the left and one on the right side). There was a statistically significant difference (p = 0.04) between the mean antero-posterior diameter of superior articular facet located on each side of atlas vertebrae, whereas not (p = 0.51) between mean antero-posterior diameter of transverse foramina. There was not any significant difference between the mean transverse diameters and areas of superior articular facets and transverse foramina located on each side of atlas vertebrae, respectively. Each of the areas of transverse foramina located on the same sides with foramen arcuale in two atlas vertebrae was less than the mean areas of transverse foramina located ipsilateral side with each foramen arcuale in thirteen atlas vertebrae. The present study provides additional information about the incidence and topography of the atlas vertebrae including foramen arcuale.
Sea ice effects in a spectral wave model: principles and practical implementation

NASA Astrophysics Data System (ADS)

Boutin, G.; Ardhuin, F.; Girard-Ardhuin, F.; Dumont, D.; Sévigny, C.

2016-12-01

Numerical wave models have their largest errors around sea ice, and their accuracy is generally unknown in the ice as very few data are available. This is largely because they do not, or in a coarse way, take into account the interactions of waves and sea ice, and because the necessary information about sea ice properties is not readily available. Recent progress have expanded our knowledge of wave scattering by sea ice as well as several dissipation processes, highlighting the need to include ice thickness and information on the ice floes size. Starting from a consistent representation of energy and dispersion in the presence of sea ice, we have redefined a set of self-consistent dissipation and scattering parameterizations for the WAVEWATCH III model which is expected to apply to a variety of ice conditions with the exception of forming ice. In our model the ice is treated as a single layer that can be fractured in many floes expected to be equivalent to circular floes with a power law distribution of diameters that is defined from the maximum diameter Dmax and a fragility parameter. This layer of ice induces a dissipation of the wave energy through basal friction (Stopa et al. The Cryosphere, 2016) and secondary creep associated with ice flexure (Cole et al. 1998), in addition to an energy-conserving scattering modeled following Kohout and Meylan (2006). The ice thickness and concentration are taken uniform over a model grid cell, and are typically provided by model products or satellite data, and are not affected by the waves. The wave model results are used to update Dmax by a probabilistic evaluation of ice break-up by the waves. This process introduces an interesting feedback on the wave scattering and dissipation. The combination of dissipation and scattering leads to spatial patterns in the wave height and directional spreading of the wave field that can be easily tested with in situ or remote sensing data (Sutherland and Gascard GRL 2016, Ardhuin et al. GRL 2016). In particular our model assumes that wave dissipation in unbroken ice is dominated by creep, which then vanishes once the ice is broken, reproducing the wave attenuation observed by Collins et al. (GRL 2015). Consistent with the low directional spread in most SAR imagery, scattering does not appear as the main factor for the attenuation of dominant swells with periods 12 to 25 s.
33 CFR 151.2030 - Ballast water discharge standard (BWDS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... possibly prevent the introduction and spread of non-indigenous aquatic invasive species. ... COMMERCIAL WASTE, AND BALLAST WATER Ballast Water Management for Control of Nonindigenous Species in Waters... maximum extent practicable that aquatic nuisance species are not discharged into waters of the United...
33 CFR 151.2030 - Ballast water discharge standard (BWDS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... possibly prevent the introduction and spread of non-indigenous aquatic invasive species. ... COMMERCIAL WASTE, AND BALLAST WATER Ballast Water Management for Control of Nonindigenous Species in Waters... maximum extent practicable that aquatic nuisance species are not discharged into waters of the United...
33 CFR 151.2030 - Ballast water discharge standard (BWDS).

Code of Federal Regulations, 2014 CFR

2014-07-01

... possibly prevent the introduction and spread of non-indigenous aquatic invasive species. ... COMMERCIAL WASTE, AND BALLAST WATER Ballast Water Management for Control of Nonindigenous Species in Waters... maximum extent practicable that aquatic nuisance species are not discharged into waters of the United...
Pigments which reflect infrared radiation from fire

DOEpatents

Berdahl, P.H.

1998-09-22

Conventional paints transmit or absorb most of the intense infrared (IR) radiation emitted by fire, causing them to contribute to the spread of fire. The present invention comprises a fire retardant paint additive that reflects the thermal IR radiation emitted by fire in the 1 to 20 micrometer ({micro}m) wavelength range. The important spectral ranges for fire control are typically about 1 to about 8 {micro}m or, for cool smoky fires, about 2 {micro}m to about 16 {micro}m. The improved inventive coatings reflect adverse electromagnetic energy and slow the spread of fire. Specific IR reflective pigments include titanium dioxide (rutile) and red iron oxide pigments with diameters of about 1 {micro}m to about 2 {micro}m and thin leafing aluminum flake pigments. 4 figs.
Preparation and Characterization of Fine-Particle NTO and Its Formulation with Al Nanopowders

NASA Astrophysics Data System (ADS)

Lee, K.-Y.; Kennedy, J. E.; Asay, B. W.; Son, S. F.; Martin, E. S.

2004-07-01

We have initiated study of the effect of nano-aluminum on the detonation performance of NTO. A novel method for the preparation of both fine-particle NTO (UF-NTO) and its formulation with Al nanopowder has been developed. Results from small-scale sensitivity tests on both the UF-NTO and aluminized NTO composite indicated that they are insensitive to impact, friction and HESD. The performance of both UF-NTO and NTO/Al mix was evaluated by detonation-spreading floret tests. At the same pressed density, it was found that, when initiated by a 3-mm-diameter flyer plate, the aluminized NTO composite produced a shallower dent on a copper witness plate than neat UF-NTO and thus was inferior to UF-NTO in detonation spreading.
Management of colon stents based on Bernoulli's principle.

PubMed

Uno, Yoshiharu

2017-03-01

The colonic self-expanding metal stent (SEMS) has been widely used for "bridge to surgery" and palliative therapy. However, if the spread of SEMS is insufficient, not only can a decompression effect not be obtained but also perforation and obstructive colitis can occur. The mechanism of occurrence of obstructive colitis and perforation was investigated by flow dynamics. Bernoulli's principle was applied, assuming that the cause of inflammation and perforation represented the pressure difference in the proximal lumen and stent. The variables considered were proximal lumen diameter, stent lumen diameter, flow rate into the proximal lumen, and fluid density. To model the right colon, the proximal lumen diameter was set at 50 mm. To model the left-side colon, the proximal lumen diameter was set at 30 mm. For both the right colon model and the left-side colon model, the difference in pressure between the proximal lumen and the stent was less than 20 mmHg, when the diameter of the stent lumen was 14 mm or more. Both the right colon model and the left-side colon model were 30 mmHg or more at 200 mL s -1 when the stent lumen was 10 mm or less. Even with an inflow rate of 90-110 mL s -1 , the pressure was 140 mmHg when the stent lumen diameter was 5 mm. In theory, in order to maintain the effectiveness of SEMS, it is necessary to keep the diameter of the stent lumen at 14 mm or more.

A computational study of crimping and expansion of bioresorbable polymeric stents

NASA Astrophysics Data System (ADS)

Qiu, T. Y.; Song, M.; Zhao, L. G.

2018-05-01

This paper studied the mechanical performance of four bioresorbable PLLA stents, i.e., Absorb, Elixir, Igaki-Tamai and RevaMedical, during crimping and expansion using the finite element method. Abaqus CAE was used to create the geometrical models for the four stents. A tri-folded balloon was created using NX software. For the stents, elastic-plastic behaviour was used, with hardening implemented by considering the increase of yield stress with the plastic strain. The tri-folded balloon was treated as linear elastic. To simulate the crimping of stents, a set of 12 rigid plates were generated around the stents with a radially enforced displacement. During crimping, the stents were compressed from a diameter of 3 mm to 1.2 mm, with the maximum stress developed at both inner and outer sides of the U-bends. During expansion, the stent inner diameter increased to 3 mm at the peak pressure and then recoiled to different final diameters after balloon deflation due to different stent designs. The maximum stress was found again at the U-bends of stents. Diameter change, recoiling effect and radial strength/stiffness were also compared for the four stents to assess the effect of design variation on stent performance. The effect of loading rate on stent deformation was also simulated by considering the time-dependent plastic behaviour of polymeric material.
Corneal Epithelium Thickness Profile in 614 Normal Chinese Children Aged 7-15 Years Old.

PubMed

Ma, Yingyan; He, Xiangui; Zhu, Xiaofeng; Lu, Lina; Zhu, Jianfeng; Zou, Haidong

2016-03-23

The purpose of the study is to describe the values and distribution of corneal epithelium thickness (CET) in normal Chinese school-aged children, and to explore associated factors with CET. CET maps were measured by Fourier-domain optical coherence tomography (FD-OCT) in normal Chinese children aged 7 to 15 years old from two randomly selected schools in Shanghai, China. Children with normal intraocular pressure were further examined for cycloplegic autorefraction, corneal curvature radius (CCR) and axial length. Central (2-mm diameter area), para-central (2- to 5-mm diameter area), and peripheral (5- to 6-mm diameter area) CET in the superior, superotemporal, temporal, inferotemporal, inferior, inferonasal, nasal, superonasal cornea; minimum, maximum, range, and standard deviation of CET within the 5-mm diameter area were recorded. The CET was thinner in the superior than in the inferior and was thinner in the temporal than in the nasal. The maximum CET was located in the inferior zone, and the minimum CET was in the superior zone. A thicker central CET was associated with male gender (p = 0.009) and older age (p = 0.037) but not with CCR (p = 0.061), axial length (p = 0.253), or refraction (p = 0.351) in the multiple regression analyses. CCR, age, and gender were correlated with para-central and peripheral CET.
Variations in the size of focal nodular hyperplasia on magnetic resonance imaging.

PubMed

Ramírez-Fuentes, C; Martí-Bonmatí, L; Torregrosa, A; Del Val, A; Martínez, C

2013-01-01

To evaluate the changes in the size of focal nodular hyperplasia (FNH) during long-term magnetic resonance imaging (MRI) follow-up. We reviewed 44 FNHs in 30 patients studied with MRI with at least two MRI studies at least 12 months apart. We measured the largest diameter of the lesion (inmm) in contrast-enhanced axial images and calculated the percentage of variation as the difference between the maximum diameter in the follow-up and the maximum diameter in the initial study. We defined significant variation in size as variation greater than 20%. We also analyzed predisposing hormonal factors. The mean interval between the two imaging studies was 35±2 months (range: 12-94). Most lesions (80%) remained stable during follow-up. Only 9 of the 44 lesions (20%) showed a significant variation in diameter: 7 (16%) decreased in size and 2 (4%) increased, with variations that reached the double of the initial size. The change in size was not related to pregnancy, menopause, or the use of birth control pills or corticoids. Changes in the size of FNHs during follow-up are relatively common and should not lead to a change in the diagnosis. These variations in size seem to be independent of hormonal factors that are considered to predispose. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.
A computational study of crimping and expansion of bioresorbable polymeric stents

NASA Astrophysics Data System (ADS)

Qiu, T. Y.; Song, M.; Zhao, L. G.

2017-10-01

This paper studied the mechanical performance of four bioresorbable PLLA stents, i.e., Absorb, Elixir, Igaki-Tamai and RevaMedical, during crimping and expansion using the finite element method. Abaqus CAE was used to create the geometrical models for the four stents. A tri-folded balloon was created using NX software. For the stents, elastic-plastic behaviour was used, with hardening implemented by considering the increase of yield stress with the plastic strain. The tri-folded balloon was treated as linear elastic. To simulate the crimping of stents, a set of 12 rigid plates were generated around the stents with a radially enforced displacement. During crimping, the stents were compressed from a diameter of 3 mm to 1.2 mm, with the maximum stress developed at both inner and outer sides of the U-bends. During expansion, the stent inner diameter increased to 3 mm at the peak pressure and then recoiled to different final diameters after balloon deflation due to different stent designs. The maximum stress was found again at the U-bends of stents. Diameter change, recoiling effect and radial strength/stiffness were also compared for the four stents to assess the effect of design variation on stent performance. The effect of loading rate on stent deformation was also simulated by considering the time-dependent plastic behaviour of polymeric material.
Omega-3 fatty acids enriched chocolate spreads using soybean and coconut oils.

PubMed

Jeyarani, T; Banerjee, T; Ravi, R; Krishna, A G Gopala

2015-02-01

Chocolate spreads were developed by incorporating two different soybean oil margarines, fat phases prepared using 85 % soybean oil (M1) and 1:1 blend of soybean oil and coconut oil (M2) with commercial palm stearin. Eight formulations were tried by varying skim milk powder (SMP)/fluid skimmed milk (FSM), type of fats (M1, M2, a commercial margarine and a table spread), sugar and cocoa powder and their quality characteristics were compared with a commercial hazelnut cocoa spread. The moisture and fat content were 5-6.1 % and 31.4-32.8 % for formulations with SMP and 21.5-24.7 % and 15.6-21.4 % respectively for those with FSM. Rheological studies of FSM spreads showed higher G″ value (loss modulus) than G' (storage modulus) indicating better spreadability. Descriptive sensory analysis revealed that the products had acceptability score of 8.3 to 10.5 (maximum score: 15). Fat extracted from spreads prepared using M1 and M2 was found to contain 43.9 and 22.3 % linoleic acid and 2.1 and 4.4 % linolenic acid respectively, were free from trans fat while the commercial hazelnut spread had 9.8 % linoleic acid but did not contain linolenic acid. Hence, the developed chocolate spreads have the potential to overcome ω-3 deficiency, ω-6/ω-3 imbalance and to enhance the health standard of people.
Finite element analysis and performance study of switched reluctance generator

NASA Astrophysics Data System (ADS)

Zhang, Qianhan; Guo, Yingjun; Xu, Qi; Yu, Xiaoying; Guo, Yajie

2017-03-01

Analyses a three-phase 12/8 switched reluctance generator (SRG) which is based on its structure and performance principle. The initial size data were calculated by MathCAD, and the simulation model was set up in the ANSOFT software environment with the maximum efficiency and the maximum output power as the main reference parameters. The outer diameter of the stator and the inner diameter of the rotor were parameterized. The static magnetic field distribution, magnetic flux, magnetic energy, torque, inductance characteristics, back electromotive force and phase current waveform of SRG is obtained by analyzing the static magnetic field and the steady state motion of two-dimensional transient magnetic field in ANSOFT environment. Finally, the experimental data of the prototype are compared with the simulation results, which provide a reliable basis for the design and research of SRG wind turbine system.
Experimental study of the influence of different resonators on thermoacoustic conversion performance of a thermoacoustic-Stirling heat engine.

PubMed

Luo, E C; Ling, H; Dai, W; Yu, G Y

2006-12-22

In this paper, an experimental study of the effect of the resonator shape on the performance of a traveling-wave thermoacoustic engine is presented. Two different resonators were tested in the thermoacoustic-Stirling heat. One resonator is an iso-diameter one, and the other is a tapered one. To have a reasonable comparison reference, we keep the same traveling-wave loop, the same resonant frequency and the same operating pressure. The experiment showed that the resonator shape has significant influence on the global performance of the thermoacoustic-Stirling heat engine. The tapered resonator gives much better performance than the iso-diameter resonator. The tapered resonator system achieved a maximum pressure ratio of about 1.3, a maximum net acoustical power output of about 450 W and a highest thermoacoustic efficiency of about 25%.
Simulated impact damage in a thick graphite/epoxy laminate using spherical indenters

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1988-01-01

A study was made to determine the extent of fiber damage caused by low-velocity impact of spherical impactors to a very thick graphite/epoxy laminate. The laminate was cut from a filament wound case being developed for the Space Shuttle solid rocket motors. The case was wound using a wet process with AS4W graphite fiber and HBRF-55A epoxy. Impacts were simulated under quasi-static conditions by pressing hemispherically shaped indenters against the laminate at different locations. The contact force and indenter diameter were varied from location to location. The forces were chosen for each indenter diameter to produce contact pressures below and above that required to initiate damage. After the forces were applied, the laminate was cut into smaller pieces so that each piece contained a test site. The pieces were then deplied and the individual plies examined to determine the extent of fiber damage. Broken fibers were found in the outer layers directly beneath the contact site. The locus of broken fibers in each layer resembled a crack normal to the direction of the fibers. The maximum length and depth of the cracks increased with increasing contact pressure and indenter diameter. The internal stresses in the laminate were calculated using Hertz's law and Love's solution for pressure applied on part of the boundary of a semi-infinite body. The maximum length and depth of the cracks were predicted using a maximum shear stress criterion. Predictions and measurements were in good agreement.
Maximum height in a conifer is associated with conflicting requirements for xylem design.

PubMed

Domec, Jean-Christophe; Lachenbruch, Barbara; Meinzer, Frederick C; Woodruff, David R; Warren, Jeffrey M; McCulloh, Katherine A

2008-08-19

Despite renewed interest in the nature of limitations on maximum tree height, the mechanisms governing ultimate and species-specific height limits are not yet understood, but they likely involve water transport dynamics. Tall trees experience increased risk of xylem embolism from air-seeding because tension in their water column increases with height because of path-length resistance and gravity. We used morphological measurements to estimate the hydraulic properties of the bordered pits between tracheids in Douglas-fir trees along a height gradient of 85 m. With increasing height, the xylem structural modifications that satisfied hydraulic requirements for avoidance of runaway embolism imposed increasing constraints on water transport efficiency. In the branches and trunks, the pit aperture diameter of tracheids decreases steadily with height, whereas torus diameter remains relatively constant. The resulting increase in the ratio of torus to pit aperture diameter allows the pits to withstand higher tensions before air-seeding but at the cost of reduced pit aperture conductance. Extrapolations of vertical trends for trunks and branches show that water transport across pits will approach zero at a heights of 109 m and 138 m, respectively, which is consistent with historic height records of 100-127 m for this species. Likewise, the twig water potential corresponding to the threshold for runaway embolism would be attained at a height of approximately 107 m. Our results suggest that the maximum height of Douglas-fir trees may be limited in part by the conflicting requirements for water transport and water column safety.
Biophysical considerations for optimizing energy delivery during Erbium:YAG laser vitreoretinal surgery

NASA Astrophysics Data System (ADS)

Berger, Jeffrey W.; Bochow, Thomas W.; Kim, Rosa Y.; D'Amico, Donald J.

1996-05-01

Er:YAG laser-mediated tissue disruption and removal results from both direct ablation and the acousto-mechanical sequelae of explosive vaporization of the tissue water. We investigated the scaling laws for photoablative and photodisruptive interactions, and interpret these results towards optimizing energy delivery for vitreoretinal surgical maneuvers. Experimental studies were performed with a free-running Er:YAG laser (100 - 300 microseconds FWHM, 0.5 - 20 mJ, 1 - 30 Hz). Energy was delivered by fiberoptic to a custom-made handpiece with a 75 - 600 micrometer quartz tip, and applied to excised, en bloc samples of bovine vitreous or model systems of saline solution. Sample temperature was measured with 33 gauge copper- constantan thermocouples. Expansion and collapse of the bubble following explosive vaporization of tissue water was optically detected. The bubble size was calculated from the period of the bubble oscillation and known material properties. A model for bubble expansion is presented based on energy principles and adiabatic gas expansion. Pressure transients associated with bubble dynamics are estimated following available experimental and analytical data. The temperature rise in vitreous and model systems depends on the pulse energy and repetition rate, but is independent of the probe-tip diameter at constant laser power; at moderate repetition rates, the temperature rise depends only on the total energy (mJ) delivered. The maximum bubble diameter increases as the cube root of the pulse energy with a reverberation period of 110 microseconds and a maximum bubble diameter of 1.2 mm following one mJ delivery to saline through a 100 micrometer tip. Our modeling studies generate predictions similar to experimental data and predicts that the maximum bubble diameter increases as the cube root of the pulse energy. We demonstrate that tissue ablation depends on radiant exposure (J/cm2), while temperature rise, bubble size, and pressure depends on total pulse energy. Further, we show that mechanical injury should be minimized by delivering low pulse energy, through small diameter probe tips, at high repetition rates. These results allow for optimization strategies relevant to achieving vitreoretinal surgical goals while minimizing the potential for unintentional injury.
Sensitivity and specificity of fluorescence microlymphography for detecting lymphedema of the lower extremity.

PubMed

Keo, Hong H; Schilling, Marianne; Büchel, Roland; Gröchenig, Ernst; Engelberger, Rolf P; Willenberg, Torsten; Baumgartner, Iris; Gretener, Silvia B

2013-06-01

Fluorescence microlymphography (FML) is used to visualize the lymphatic capillaries. A maximum spread of the fluorescence dye of ≥ 12 mm has been suggested for the diagnosis of lymphedema. However, data on sensitivity and specificity are lacking. The aim of this study was to investigate the accuracy of FML for diagnosing lymphedema in patients with leg swelling. Patients with lower extremity swelling were clinically assessed and separated into lymphedema and non-lymphatic edema groups. FML was studied in all affected legs and the maximum spread of lymphatic capillaries was measured. Test accuracy and receiver operator characteristic (ROC) analysis was performed to assess possible threshold values that predict lymphedema. Between March 2008 and August 2011 a total of 171 patients (184 legs) with a median age of 43.5 (IQR 24, 54) years were assessed. Of those, 94 (51.1%) legs were diagnosed with lymphedema. The sensitivity, specificity, positive and negative likelihood ratio and positive and negative predictive value were 87%, 64%, 2.45, 0.20, 72% and 83% for the 12-mm cut-off level and 79%, 83%, 4.72, 0.26, 83% and 79% for the 14-mm cut-off level, respectively. The area under the ROC curve was 0.82 (95% CI: 0.76, 0.88). Sensitivity was higher in the secondary versus primary lymphedema (95.0% vs 74.3%, p = 0.045). No major adverse events were observed. In conclusion, FML is a simple and safe technique for detecting lymphedema in patients with leg swelling. A cut-off level of ≥ 14-mm maximum spread has a high sensitivity and high specificity of detecting lymphedema and should be chosen.
Changes in Cirrus Cloudiness and their Relationship to Contrails

NASA Technical Reports Server (NTRS)

Minnis, Patrick; Ayers, J. Kirk; Palikonda, Rabindra; Doelling, David R.; Schumann, Ulrich; Gierens, Klaus

2001-01-01

Condensation trails, or contrails, formed in the wake of high-altitude aircraft have long been suspected of causing the formation of additional cirrus cloud cover. More cirrus is possible because 10 - 20% of the atmosphere at typical commercial flight altitudes is clear but ice-saturated. Since they can affect the radiation budget like natural cirrus clouds of equivalent optical depth and microphysical properties, contrail -generated cirrus clouds are another potential source of anthropogenic influence on climate. Initial estimates of contrail radiative forcing (CRF) were based on linear contrail coverage and optical depths derived from a limited number of satellite observations. Assuming that such estimates are accurate, they can be considered as the minimum possible CRF because contrails often develop into cirrus clouds unrecognizable as contrails. These anthropogenic cirrus are not likely to be identified as contrails from satellites and would, therefore, not contribute to estimates of contrail coverage. The mean lifetime and coverage of spreading contrails relative to linear contrails are needed to fully assess the climatic effect of contrails, but are difficult to measure directly. However, the maximum possible impact can be estimated using the relative trends in cirrus coverage over regions with and without air traffic. In this paper, the upper bound of CRF is derived by first computing the change in cirrus coverage over areas with heavy air traffic relative to that over the remainder of the globe assuming that the difference between the two trends is due solely to contrails. This difference is normalized to the corresponding linear contrail coverage for the same regions to obtain an average spreading factor. The maximum contrail-cirrus coverage, estimated as the product of the spreading factor and the linear contrail coverage, is then used in the radiative model to estimate the maximum potential CRF for current air traffic.
Properties of Hail Storms over China and the United States from the Tropical Rainfall Measuring Mission

NASA Technical Reports Server (NTRS)

Ni, Xiang; Liu, Chuntao; Zhang, Qinghong; Cecil, Daniel J.

2016-01-01

A 16-yr record of hail reports over the southeast US and from weather stations in China are collocated with Precipitation Features (PF) derived from the Tropical Rainfall Measurement Mission (TRMM) radar and passive microwave observations. While U.S. hail reports are dominated by cases with hail size greater than 19 mm, hail reports in China mostly include diameters of 1-10 nm and mostly occur over the Tibetan Plateau. The fraction of PFs collocated with hail reports (hail PFs) reaches 3% in the plains of the U.S. In China, the fraction is higher in high elevation regions than low elevation regions. Hail PFs in the U.S. show lower brightness temperatures, higher lightning flash rates, stronger maximum reflectivity, and higher echo tops than those in China, consistent with the larger hail diameters in the U.S. reports. The average near surface maximum reflectivity of hail PFs at higher elevations (greater than or equal to 2000 m) in China is about 5 dB smaller than those at low elevations. Larger hail is reported with PFs having stronger maximum reflectivity above 6 km, though the median of maximum reflectivity values at levels below 5 km is close among the storms with large and small hail sizes.
Continuous measurement of aortic dimensions in Turner syndrome: a cardiovascular magnetic resonance study.

PubMed

Subramaniam, Dhananjay Radhakrishnan; Stoddard, William A; Mortensen, Kristian H; Ringgaard, Steffen; Trolle, Christian; Gravholt, Claus H; Gutmark, Ephraim J; Mylavarapu, Goutham; Backeljauw, Philippe F; Gutmark-Little, Iris

2017-02-24

Severity of thoracic aortic disease in Turner syndrome (TS) patients is currently described through measures of aorta size and geometry at discrete locations. The objective of this study is to develop an improved measurement tool that quantifies changes in size and geometry over time, continuously along the length of the thoracic aorta. Cardiovascular magnetic resonance (CMR) scans for 15 TS patients [41 ± 9 years (mean age ± standard deviation (SD))] were acquired over a 10-year period and compared with ten healthy gender and age-matched controls. Three-dimensional aortic geometries were reconstructed, smoothed and clipped, which was followed by identification of centerlines and planes normal to the centerlines. Geometric variables, including maximum diameter and cross-sectional area, were evaluated continuously along the thoracic aorta. Distance maps were computed for TS and compared to the corresponding maps for controls, to highlight any asymmetry and dimensional differences between diseased and normal aortae. Furthermore, a registration scheme was proposed to estimate localized changes in aorta geometry between visits. The estimated maximum diameter from the continuous method was then compared with corresponding manual measurements at 7 discrete locations for each visit and for changes between visits. Manual measures at the seven positions and the corresponding continuous measurements of maximum diameter for all visits considered, correlated highly (R-value = 0.77, P < 0.01). There was good agreement between manual and continuous measurement methods for visit-to-visit changes in maximum diameter. The continuous method was less sensitive to inter-user variability [0.2 ± 2.3 mm (mean difference in diameters ± SD)] and choice of smoothing software [0.3 ± 1.3 mm]. Aortic diameters were larger in TS than controls in the ascending [TS: 13.4 ± 2.1 mm (mean distance ± SD), Controls: 12.6 ± 1 mm] and descending [TS: 10.2 ± 1.3 mm (mean distance ± SD), Controls: 9.5 ± 0.9 mm] thoracic aorta as observed from the distance maps. An automated methodology is presented that enables rapid and precise three-dimensional measurement of thoracic aortic geometry, which can serve as an improved tool to define disease severity and monitor disease progression. ClinicalTrials.gov Identifier - NCT01678274 . Registered - 08.30.2012.
Simulation of the spreading of a gas-propelled micro-droplet upon impact on a dry surface using a lattice-Boltzmann approach

NASA Astrophysics Data System (ADS)

Ebrahim, Mahsa; Ortega, Alfonso; Delbosc, Nicolas; Wilson, Mark C. T.; Summers, Jonathan L.

2017-07-01

Spray cooling is one of the most promising methods of cooling high heat flux electronics. Depending on the type of the nozzle, spray cooling can be categorized as single-phase or two-phase. In the latter, which is known to be more effective, a secondary gas is used to further pressurize the liquid and form smaller droplets at higher velocities. The gas is also assumed to assist the spreading phase by imposing normal and tangential forces on the droplet free surface which adds to the complicated hydrodynamics of the droplet impact. Moreover, the order of magnitude of droplet size in spray cooling is 10-6 m, thereby introducing a low Weber and Reynolds numbers' impact regime which heretofore has not been well understood. A 3D lattice Boltzmann method was implemented to simulate the impact of a single micro-droplet on a dry surface both in ambient air and under a stagnation gas flow. Two cases were closely compared and correlations were proposed for the instantaneous spreading diameter. Contrary to recent findings at higher impact Weber and Reynolds numbers, it was found that a stagnation flow only significantly affects the spreading phase for Ca* ≥ 0.35 but has little influence on the receding physics.
DISCOVERING SPATIO-TEMPORAL MODELS OF THE SPREAD OF WEST NILE VIRUS

EPA Science Inventory

Understanding interactions among pathogens, hosts, and the environment is important in developing rapid response to disease outbreak. To facilitate the development of control strategies during an outbreak, we have developed a tool for utilizing data to its maximum extent to deter...
Shuttle spectrum despreader

NASA Technical Reports Server (NTRS)

1976-01-01

The results of the spread spectrum despreader project are reported and three principal products are designed and tested. The products are, (1) a spread spectrum despreader breadboard, (2) associated test equipment consisting of a spectrum spreader and bit reconstruction/error counter and (3) paper design of a Ku-band receiver which would incorporate the despreader as a principal subsystem. The despreader and test set are designed for maximum flexibility. A choice of unbalanced quadriphase or biphase shift keyed data modulation is available. Selectable integration time and threshold voltages on the despreader further lend true usefulness as laboratory test equipment to the delivered hardware.
Outlook for ash in your forest: results of emerald ash borer research and implications for management

Treesearch

Kathleen S. Knight

2014-01-01

Since its accidental introduction near Detroit, Michigan, in the mid-1990s, emerald ash borer (EAB) has rapidly spread through much of the U.S. and adjacent Canada, leaving millions of dead ash trees in Midwestern states (4,11). Unfortunately, EAB attacks trees as small as an inch in stem diameter and it attacks all five ash species native to the region - white, green...
The Detection of Collisional and Scattering Processes in the Asteroid-Meteoroid Continuum

NASA Astrophysics Data System (ADS)

Lai, H. R.; Connos, M. A.; Russell, C. T.; Wei, H. Y.

2014-04-01

Optical and radar observations have enabled the compilation of a useful inventory of near-Earth objects down to a diameter of approximately 500m, but at smaller diameters the catalogue is sparse. This is unacceptable for several reasons. First, the most hazardous size range based on damage per impact on Earth times expected impact rate is near 50m and second, we do not know if either the spatial distribution of objects or their behavior is similar to that of the larger objects. We have reason to believe they are importantly different. Near Earth Objects evolve due to collisions with other objects. Disruptive collisions of large objects say 200m in diameter are rare because such objects are "rare" and the impactors that could disrupt a 200m class object are rare. However, near the Earth, collisions are expected to occur at relative velocities of near 20 km/sec and such a speed could disrupt a body 106 times more massive (100 times larger diameter). Our studies show that collisions that can produce objects in the range 10 to 100m in diameter are "frequent" in near-Earth space. Our studies of the asteroid 2201 Oljato at Venus and asteroid 138175 near Earth indicates that both asteroids have coorbital debris clouds presumably caused by a past non-disruptive but debris-producing collision. This has the effect of spreading the hazardous material out of the known orbit so that a false sense of security is had when the parent body is safely past the Earth. We can detect a subset of the debris trail by their destructive impacts because they create a cloud of charged nanoscale dust which in turn creates a magnetic "cloud" that enables the dust cloud to be weighed and its location roughly identified. This shows spreading in longitude, latitude, and heliocentric radius from the parent on a time scale of decades. This is much faster than some modelers have expected and over a broader range, suggesting that the debris trail receives more of the impactor momentum than anticipated. This possibly depends on the elasticity of the target asteroid. In any event, we now have a new qualitative method of tracking debris tails of hazardous materials using existing assets in space
TU-H-CAMPUS-TeP3-03: Dose Enhancement by Gold Nanoparticles Around the Bragg Peak of Proton Beams

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

Kwon, J; Sutherland, K; Hashimoto, T

2016-06-15

Purpose: To make clear the spatial distribution of dose enhancement around gold nanoparticles (GNPs) located near the proton Bragg peak, and to evaluate the potential of GNPs as a radio sensitizer. Methods: The dose enhancement by electrons emitted from GNPs under proton irradiation was estimated by Geant4 Monte Carlo simulation toolkit in two steps. In an initial macroscopic step, 100 and 195 MeV proton beams were incident on a water cube, 30 cm on a side. Energy distributions of protons were calculated at four depths, 50% and 75% proximal to the Bragg peak, 100% peak, and 75% distal to themore » peak (P50, P75, Peak, and D75, respectively). In a subsequent microscopic step, protons with the energy distribution calculated above were incident on a 20 nm diameter GNP in a nanometer-size water box and the spatial distribution of dose around the GNP was determined for each energy distribution. The dose enhancement factor (DEF) was also deduced. Results: The dose enhancement effect was spread to several tens of nanometers in the both depth and radial directions. The enhancement area increased in the order of P50, P75, Peak, and D75 for both cases with 100 and 195 MeV protons. In every position around the Bragg peak, the 100 MeV beam resulted in a higher dose enhancement than the 195 MeV beam. At P75, the average and maximum DEF were 3.9 and 17.0 for 100 MeV, and 3.5 and 16.2 for 195 MeV, respectively. These results indicate that lower energy protons caused higher dose enhancement in this incident proton energy range. Conclusion: The dose enhancement around GNPs spread as the position in the Bragg peak region becomes deeper and depends on proton energy. It is expected that GNPs can be used as a radio sensitizer with consideration of the location and proton beam energy.« less

Experimental investigation of an axisymmetric free jet with an initially uniform velocity profile

NASA Technical Reports Server (NTRS)

Labus, T. L.; Symons, E. P.

1972-01-01

An experimental investigation was conducted to determine the flow characteristics of a circular free helium jet having an initially uniform velocity profile. Complete velocity profiles are presented at Reynolds numbers of 1027 and 4571 at 0, 3, 6, 10, 15, and 20 nozzle diameters (where possible) from the nozzle exit. Centerline velocity decay and potential core length were obtained over a range of Reynolds numbers from 155 to 5349 at distances up to and including 25 nozzle diameters from the nozzle exit. The angles of spread associated with the diffusion of the jet downstream of the nozzle are also given. Axial jet momentum flux and entrained mass flux, at various distances downstream of the nozzle, are presented as a function of the jet Reynolds number.
100 mm diameter rod laser amplifiers made of different Nd:glasses

NASA Astrophysics Data System (ADS)

Shaykin, A. A.; Kuzmin, A. A.; Shaikin, I. A.; Potemkin, A. K.; Arbuzov, V. I.; Hu, Lili; Wen, Lei; Khazanov, Е A.

2018-03-01

We measured the dependence of the weak signal gain of 100 mm diameter rod amplifiers on pump energy and transverse coordinates for four neodymium glass grades. The highest gain was obtained in N31-05 (China), and the highest radial gain uniformity in KGSS-0180 glass (Russia). The data obtained enable the optimal glass grade to be chosen for each specific problem by finding a compromise between maximum output energy and minimum distortion of beam profile.
Flow and criticality in the open cycle gas core.

NASA Technical Reports Server (NTRS)

Kunze, J. F.; Lofthouse, J. H.

1971-01-01

A series of flowing gas experiments using air, argon, and freon has been conducted in Idaho. The purpose is to study methods of obtaining flow patterns which would create maximum possible system reactivity consistent with an acceptably low uranium to coolant-gas loss ratio. These have been conducted on both ?two-dimensional' and truly three-dimensional spherical configurations of diameters 18 to 42 inches. The larger diameter is that proposed for a minimum cost flowing gas critical experiment, and the size extremes make extrapolations to the large 6 and 8 foot diameter configurations more reliable. Results show that large enough inner gas (fuel) volume fractions can be achieved to attain criticality.
Measurement of nanoscale molten polymer droplet spreading using atomic force microscopy

NASA Astrophysics Data System (ADS)

Soleymaniha, Mohammadreza; Felts, Jonathan R.

2018-03-01

We present a technique for measuring molten polymer spreading dynamics with nanometer scale spatial resolution at elevated temperatures using atomic force microscopy (AFM). The experimental setup is used to measure the spreading dynamics of polystyrene droplets with 2 μm diameters at 115-175 °C on sapphire, silicon oxide, and mica. Custom image processing algorithms determine the droplet height, radius, volume, and contact angle of each AFM image over time to calculate the droplet spreading dynamics. The contact angle evolution follows a power law with time with experimentally determined values of -0.29 ± 0.01, -0.08 ± 0.02, and -0.21 ± 0.01 for sapphire, silicon oxide, and mica, respectively. The non-zero steady state contact angles result in a slower evolution of contact angle with time consistent with theories combining molecular kinetic and hydrodynamic models. Monitoring the cantilever phase provides additional information about the local mechanics of the droplet surface. We observe local crystallinity on the molten droplet surface, where crystalline structures appear to nucleate at the contact line and migrate toward the top of the droplet. Increasing the temperature from 115 °C to 175 °C reduced surface crystallinity from 35% to 12%, consistent with increasingly energetically favorable amorphous phase as the temperature approaches the melting temperature. This platform provides a way to measure spreading dynamics of extremely small volumes of heterogeneously complex fluids not possible through other means.
Pupillometry as an indicator of L-DOPA dosages in Parkinson's disease patients.

PubMed

Bartošová, O; Bonnet, C; Ulmanová, O; Šíma, M; Perlík, F; Růžička, E; Slanař, O

2018-04-01

Dopamine was shown to induce mydriasis by excitation of alpha-adrenergic receptors at the dilator pupillae muscle. Pupilla diameter may thus serve as an indirect measure of peripheral pharmacokinetics of L-DOPA and dopamine. The aim of this study is to evaluate the effect of L-DOPA dosage on pupillometric parameters in Parkinson's disease (PD) patients. Sixteen PD patients and 14 healthy control subjects (CS) were studied. The statistical analysis revealed significant differences between CS and PD patients for the mean maximum and minimum pupil diameters (p = 0.017, p = 0.028, respectively), with higher values found in PD. Moreover, a significant dose-response relationship was found between the maximum pupil diameter and both the morning L-DOPA dose (R 2 = 0.78) and the total daily L-DOPA dose (R 2 = 0.93). A sigmoid-shaped curve best describes the dose-response relationship, with a ceiling effect at about 400 mg L-DOPA daily dose. In conclusion, measuring pupillometric parameters represents a sensitive tool for non-invasive evaluation of the peripheral effect of L-DOPA, especially with daily doses below 400 mg L-DOPA.
Proton acceleration by irradiation of isolated spheres with an intense laser pulse

DOE PAGES

Ostermayr, Tobias M.; Haffa, D.; Hilz, P.; ...

2016-09-26

We report on experiments irradiating isolated plastic spheres with a peak laser intensity of 2–3 × 10 20 W cm –2. With a laser focal spot size of 10 μm full width half maximum (FWHM) the sphere diameter was varied between 520 nm and 19.3 μm. Maximum proton energies of ~ 25 MeV are achieved for targets matching the focal spot size of 10 μm in diameter or being slightly smaller. For smaller spheres the kinetic energy distributions of protons become nonmonotonic, indicating a change in the accelerating mechanism from ambipolar expansion towards a regime dominated by effects caused bymore » Coulomb repulsion of ions. The energy conversion efficiency from laser energy to proton kinetic energy is optimized when the target diameter matches the laser focal spot size with efficiencies reaching the percent level. The change of proton acceleration efficiency with target size can be attributed to the reduced cross-sectional overlap of subfocus targets with the laser. Reported experimental observations are in line with 3D3V particle in cell simulations. In conclusion, they make use of well-defined targets and point out pathways for future applications and experiments.« less
Proton acceleration by irradiation of isolated spheres with an intense laser pulse

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

Ostermayr, Tobias M.; Haffa, D.; Hilz, P.

We report on experiments irradiating isolated plastic spheres with a peak laser intensity of 2–3 × 10 20 W cm –2. With a laser focal spot size of 10 μm full width half maximum (FWHM) the sphere diameter was varied between 520 nm and 19.3 μm. Maximum proton energies of ~ 25 MeV are achieved for targets matching the focal spot size of 10 μm in diameter or being slightly smaller. For smaller spheres the kinetic energy distributions of protons become nonmonotonic, indicating a change in the accelerating mechanism from ambipolar expansion towards a regime dominated by effects caused bymore » Coulomb repulsion of ions. The energy conversion efficiency from laser energy to proton kinetic energy is optimized when the target diameter matches the laser focal spot size with efficiencies reaching the percent level. The change of proton acceleration efficiency with target size can be attributed to the reduced cross-sectional overlap of subfocus targets with the laser. Reported experimental observations are in line with 3D3V particle in cell simulations. In conclusion, they make use of well-defined targets and point out pathways for future applications and experiments.« less
Low-thrust chemical propulsion system propellant expulsion and thermal conditioning study

NASA Technical Reports Server (NTRS)

Merino, F.; Wakabayashi, I.; Pleasant, R. L.; Hill, M.

1982-01-01

Thermal conditioning systems for satisfying engine net positive suction pressure (NPSP) requirements, and propellant expulsion systems for achieving propellant dump during a return-to-launch site (RTLS) abort were studied for LH2/LO2 and LCH4/LO2 upper stage propellant combinations. A state-of-the-art thermal conditioning system employing helium injection beneath the liquid surface shows the lowest weight penalty for LO2 and LCH4. A technology system incorporating a thermal subcooler (heat exchanger) for engine NPSP results in the lowest weight penalty for the LH2 tank. A preliminary design of two state-of-the-art and two new technology systems indicates a weight penalty difference too small to warrant development of a LH2 thermal subcooler. Analysis results showed that the LH2/LO2 propellant expulsion system is optimized for maximum dump line diameters, whereas the LCH4/LO2 system is optimized for minimum dump line diameter (LCH4) and maximum dump line diameter (LO2). The primary uncertainty is the accurate determination of two-phase flow rates through the dump system; experimentation is not recommended because this uncertainty is not considered significant.
Irradiation of TZM: Uranium dioxide fuel pin at 1700 K

NASA Technical Reports Server (NTRS)

Mcdonald, G. E.

1973-01-01

A fuel pin clad with TZM and containing solid pellets of uranium dioxide was fission heated in a static helium-cooled capsule at a maximum surface temperature of 1700 K for approximately 1000 hr and to a total burnup of 2.0 percent of the uranium-235. The results of the postirradiation examination indicated: (1) A transverse, intergranular failure of the fuel pin occurred when the fuel pin reached 2.0-percent burnup. This corresponds to 1330 kW-hr/cu cm, where the volume is the sum of the fuel, clad, and void volumes in the fuel region. (2) The maximum swelling of the fuel pin was less than 1.5 percent on the fuel-pin diameter. (3) There was no visible interaction between the TZM clad and the UO2. (4) Irradiation at 1700 K produced a course-grained structure, with an average grain diameter of 0.02 centimeter and with some of the grains extending one-half of the thickness of the clad. (5) Below approximately 1500 K, the irradiation of the clad produced a moderately fine-grained structure, with an average grain diameter of 0.004 centimeter.
Wolter-Schwarzschild optics for the extreme-ultraviolet - The Berkeley stellar spectrometer and the EUV Explorer

NASA Technical Reports Server (NTRS)

Malina, R. F.; Bowyer, S.; Finley, D.; Cash, W.

1979-01-01

The design, fabrication and performance of two Wolter-Schwarzschild grazing incidence optics are described. Both telescopes have been figured by single point diamond turning and have achieved better than 15-arcsec on-axis imaging. The telescope for the stellar spectrometer is an f/10 Type II system with an effective area of 225 sq cm at 250 A and 300 cm2 at 500 A. The primary has a maximum diameter of 38 cm and was fabricated in three elements. The copper-plated aluminum substrate was diamond turned; following nickel plating, the surface was polished and coated with evaporated gold. The performance during a sounding rocket flight is discussed. The prototype telescope for the Extreme Ultraviolet Explorer is an f/1.24 Type I system with an effective field of view of 5.0-deg diameter. The telescope has a maximum diameter of 40 cm and was fabricated as a single element. The aluminum substrate is to be diamond turned; the nickel plated surface will be polished and electroplated with gold. The design choice and defocusing optimization aimed at maximizing the field of view and number of image pixels is examined.
Fabrication of two one-fifth scale fiber composite flywheels

NASA Astrophysics Data System (ADS)

1980-04-01

Two fiber composite flywheel rotors were fabricated. These flywheels are scaled down versions of two automotive flywheels built for Sandia Laboratories. The flywheels store a maximum of 0.97 kWh of kinetic energy. Energy density is 87 Wh/kg at the maximum operating speed of 56,000 rpm. The nominal flywheel dimensions are 35 cm diameter by 13 cm axial height. The weight of the flywheel rotor assembly is 11.16 kg.
33 CFR 151.1511 - Ballast water discharge standard (BWDS).

Code of Federal Regulations, 2014 CFR

2014-07-01

... COMMERCIAL WASTE, AND BALLAST WATER Ballast Water Management for Control of Nonindigenous Species in the... maximum extent practicable that aquatic nuisance species are not discharged into waters of the United..., practicable, and/or may possibly prevent the introduction and spread of non-indigenous aquatic invasive...
33 CFR 151.1511 - Ballast water discharge standard (BWDS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... COMMERCIAL WASTE, AND BALLAST WATER Ballast Water Management for Control of Nonindigenous Species in the... maximum extent practicable that aquatic nuisance species are not discharged into waters of the United..., practicable, and/or may possibly prevent the introduction and spread of non-indigenous aquatic invasive...
33 CFR 151.1511 - Ballast water discharge standard (BWDS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... COMMERCIAL WASTE, AND BALLAST WATER Ballast Water Management for Control of Nonindigenous Species in the... maximum extent practicable that aquatic nuisance species are not discharged into waters of the United..., practicable, and/or may possibly prevent the introduction and spread of non-indigenous aquatic invasive...
A three-dimensional finite element evaluation of magnetic attachment attractive force and the influence of the magnetic circuit.

PubMed

Kumano, Hirokazu; Nakamura, Yoshinori; Kanbara, Ryo; Takada, Yukyo; Ochiai, Kent T; Tanaka, Yoshinobu

2014-01-01

The finite element method has been considered to be excellent evaluative technique to study magnetic circuit optimization. The present study analyzed and quantitatively evaluated the different effects of magnetic circuit on attractive force and magnetic flux density using a three-dimensional finite element method for comparative evaluation. The diameter of a non-magnetic material in the shield disk of a magnetic assembly was variably increased by 0.1 mm to a maximum 2.0 mm in this study design. The analysis results demonstrate that attractive force increases until the diameter of the non-magnetic spacing material reaches a diameter of 0.5 mm where it peaks and then decreases as the overall diameter increases over 0.5 mm. The present analysis suggested that the attractive force for a magnetic attachment is optimized with an appropriate magnetic assembly shield disk diameter using a non-magnetic material to effectively change the magnetic circuit efficiency and resulting retention.
Parametric Investigation of Thrust Augmentation by Ejectors on a Pulsed Detonation Tube

NASA Technical Reports Server (NTRS)

Wilson, Jack; Sgondea, Alexandru; Paxson, Daniel E.; Rosenthal, Bruce N.

2006-01-01

A parametric investigation has been made of thrust augmentation of a 1 in. diameter pulsed detonation tube by ejectors. A set of ejectors was used which permitted variation of the ejector length, diameter, and nose radius, according to a statistical design of experiment scheme. The maximum augmentation ratios for each ejector were fitted using a polynomial response surface, from which the optimum ratios of ejector diameter to detonation tube diameter, and ejector length and nose radius to ejector diameter, were found. Thrust augmentation ratios above a factor of 2 were measured. In these tests, the pulsed detonation device was run on approximately stoichiometric air-hydrogen mixtures, at a frequency of 20 Hz. Later measurements at a frequency of 40 Hz gave lower values of thrust augmentation. Measurements of thrust augmentation as a function of ejector entrance to detonation tube exit distance showed two maxima, one with the ejector entrance upstream, and one downstream, of the detonation tube exit. A thrust augmentation of 2.5 was observed using a tapered ejector.
Maximizing ion current rectification in a bipolar conical nanopore fluidic diode using optimum junction location.

PubMed

Singh, Kunwar Pal

2016-10-12

The ion current rectification has been obtained as a function of the location of a heterojunction in a bipolar conical nanopore fluidic diode for different parameters to determine the junction location for maximum ion current rectification using numerical simulations. Forward current peaks for a specific location of the junction and reverse current decreases with the junction location due to a change in ion enrichment/depletion in the pore. The optimum location of the heterojunction shifts towards the tip with base/tip diameter and surface charge density, and towards the base with the electrolyte concentration. The optimum location of the heterojunction has been approximated by an equation as a function of pore length, base/tip diameter, surface charge density and electrolyte concentration. The study is useful to design a rectifier with maximum ion current rectification for practical purposes.
A preliminary report on the study of the impact sites and particles of the solar maximum satellite thermal blanket

NASA Technical Reports Server (NTRS)

Zook, H. A.

1985-01-01

A preliminary study of the work on examination of the impact pits in, or penetrations through, the thermal blankets of the Solar Maximum Satellite is presented. The three largest pieces of the thermal blanket were optically scanned with a total surface area of about one half square meter. Over 1500 impact sites of all sizes, including 432 impacts larger than 40 microns in diameter, have been documented. Craters larger in diameter than about 100 microns found on the 75 micron thick Kapton first sheet of the main electronics box blanket are actually holes and constitute perforations through the blanket. A summary of the impact pit population that were found is given. The chemical study of these craters is only in the initial stages, with only about 250 chemical spectra of particles observed in or around impact pits or in the debris pattern being recorded.
Predictive variables for the biological behaviour of basal cell carcinoma of the face: relevance of morphometry of the nuclei.

PubMed

Appel, T; Bierhoff, E; Appel, K; von Lindern, J-J; Bergé, S; Niederhagen, B

2003-06-01

We did a morphometric analysis of 130 histological sections of basal cell carcinoma (BCC) of the face to find out whether morphometric variables in the structure of the nuclei of BCC cells could serve as predictors of the biological behaviour. We considered the following variables: maximum and minimum diameters, perimeter, nuclear area and five form factors that characterise and quantify the shape of a structure (axis ratio, shape factor, nuclear contour index, nuclear roundness and circumference ratio). We did a statistical analysis of primary and recurring tumours and four histology-based groups (multifocal superficial BCCs, nodular BCCs, sclerosing BCCs and miscellaneous forms) using a two-sided t test for independent samples. Multifocal superficial BCCs showed significantly smaller values for the directly measured variables (maximum and minimum diameters, perimeter and nuclear area). Morphometry could not distinguish between primary and recurring tumours.
SU-F-18C-11: Diameter Dependency of the Radial Dose Distribution in a Long Polyethylene Cylinder

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

Bakalyar, D; McKenney, S; Feng, W

Purpose: The radial dose distribution in the central plane of a long cylinder following a long CT scan depends upon the diameter and composition of the cylinder. An understanding of this behavior is required for determining the spatial average of the dose in the central plane. Polyethylene, the material for construction of the TG200/ICRU phantom (30 cm in diameter) was used for this study. Size effects are germane to the principles incorporated in size specific dose estimates (SSDE); thus diameter dependency was explored as well. Method: ssuming a uniform cylinder and cylindrically symmetric conditions of irradiation, the dose distribution canmore » be described using a radial function. This function must be an even function of the radial distance due to the conditions of symmetry. Two effects are accounted for: The direct beam makes its weakest contribution at the center while the contribution due to scatter is strongest at the center and drops off abruptly at the outer radius. An analytic function incorporating these features was fit to Monte Carlo results determined for infinite polyethylene cylinders of various diameters. A further feature of this function is that it is integrable. Results: Symmetry and continuity dictate a local extremum at the center which is a minimum for the larger sizes. The competing effects described above can Resultin an absolute maximum occurring between the center and outer edge of the cylinders. For the smallest cylinders, the maximum dose may occur at the center. Conclusion: An integrable, analytic function can be used to characterize the radial dependency of dose for cylindrical CT phantoms of various sizes. One use for this is to help determine average dose distribution over the central cylinder plane when equilibrium dose has been reached.« less

Statistical properties of the Strehl ratio as a function of pupil diameter and level of adaptive optics correction following atmospheric propagation.

PubMed

Shellan, Jeffrey B

2004-08-01

The propagation of an optical beam through atmospheric turbulence produces wave-front aberrations that can reduce the power incident on an illuminated target or degrade the image of a distant target. The purpose of the work described here was to determine by computer simulation the statistical properties of the normalized on-axis intensity--defined as (D/r0)2 SR--as a function of D/r0 and the level of adaptive optics (AO) correction, where D is the telescope diameter, r0 is the Fried coherence diameter, and SR is the Strehl ratio. Plots were generated of (D/r0)2 (SR) and sigmaSR/(SR), where (SR) and sigma(SR) are the mean and standard deviation, respectively, of the SR versus D/r0 for a wide range of both modal and zonal AO correction. The level of modal correction was characterized by the number of Zernike radial modes that were corrected. The amount of zonal AO correction was quantified by the number of actuators on the deformable mirror and the resolution of the Hartmann wave-front sensor. These results can be used to determine the optimum telescope diameter, in units of r0, as a function of the AO design. For the zonal AO model, we found that maximum on-axis intensity was achieved when the telescope diameter was sized so that the actuator spacing was equal to approximately 2r0. For modal correction, we found that the optimum value of D/r0 (maximum mean on-axis intensity) was equal to 1.79Nr + 2.86, where Nr is the highest Zernike radial mode corrected.
Effect of tank diameter on thermal behavior of gasoline and diesel storage tanks fires.

PubMed

Leite, Ricardo Machado; Centeno, Felipe Roman

2018-01-15

Studies on fire behavior are extremely important as they contribute in a firefighting situation or even to avoid such hazard. Experimental studies of fire in real scale are unfeasible, implying that reduced-scale experiments must be performed, and results extrapolated to the range of interest. This research aims to experimentally study the fire behavior in tanks of 0.04m, 0.20m, 0.40m, 0.80m and 4.28m diameter, burning regular gasoline or diesel oil S-500. The following parameters were here obtained: burning rates, burning velocities, heat release rates, flame heights, and temperature distributions adjacent to the tank. Such parameters were obtained for each tank diameter with the purpose of correlating the results and understanding the relationship of each parameter for the different geometrical scale of the tanks. Asymptotic results for larger tanks were found as (regular gasoline and diesel oil S-500, respectively): burning rates 0.050kg/(m 2 s) and 0.031kg/(m 2 s), burning velocities 4.0mm/min and 2.5mm/min, heat release rates per unit area 2200kW/m 2 and 1500kW/m 2 , normalized averaged flame heights (H i /D, where H i is the average flame height, D is the tank diameter) 0.9 and 0.8. Maximum temperatures for gasoline pools were higher than for diesel oil pools, and temperature gradients close to the tanks were also higher for the former fuel. The behavior of the maximum temperature was correlated as a function of the tank diameter, the heat release rate of each fuel and the dimensionless distance from the tank. Copyright © 2017 Elsevier B.V. All rights reserved.
New predictor of aortic enlargement in uncomplicated type B aortic dissection based on elliptic Fourier analysis.

PubMed

Sato, Hiroshi; Ito, Toshiro; Kuroda, Yosuke; Uchiyama, Hiroki; Watanabe, Toshitaka; Yasuda, Naomi; Nakazawa, Junji; Harada, Ryo; Kawaharada, Nobuyoshi

2017-12-01

This study aimed to re-examine the conventional predictive factors for dissected aortic enlargement, such as the aortic and false lumen diameter and to consider whether the morphological elements of the dissected aorta could be predictors by quantifying the 'shape' of the true lumen based on elliptic Fourier analysis. A total of 80 patients with uncomplicated type B aortic dissection were included. The patients were divided into 'Enlargement group' and 'No Change group.' Between the 2 groups, the mean systolic blood pressure during follow-up, aortic and false lumen maximum diameters, and analysed morphological data were compared using each statistical method. The maximum aortic and false lumen diameters were significantly larger in the Enlargement group than in the No Change group (39.3 vs 35.9 mm; P = 0.0058) (23.5 vs 18.2 mm; P = 0.000095). The principal component 1, which is the data calculated by elliptic Fourier analysis, was significantly lower in the Enlargement group than in the No Change group (0.020 vs - 0.072; P = 0.000049). The mean systolic blood pressure ≥130 mmHg, aortic diameter, false lumen diameter and principal component 1 were included in the Cox proportional hazard model as covariates to determine the significant predictive variable. Principal component 1 demonstrated the only significance with aortic enlargement on multivariate analysis (odds ratio = 0.32; P = 0.048). The analysed and calculated morphological data of the shape of the true lumen can be more effective predictive factors of aortic enlargement of type B dissection than the conventional factors. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
The mare: a 1000-pound guinea pig for study of the ovulatory follicular wave in women.

PubMed

Ginther, O J

2012-03-15

The mare is a good comparative model for study of ovarian follicles in women, owing to striking similarities in follicular waves and the mechanism for selection of a dominant follicle. Commonality in follicle dynamics between mares and women include: (1) a ratio of 2.2:1 (mare:woman) in diameter of the largest follicle at wave emergence when the wave-stimulating FSH surge reaches maximum, in diameter increase of the two largest follicles between emergence and the beginning of deviation between the future dominant and subordinate follicles, in diameter of each of the two largest follicles at the beginning of deviation, and in maximum diameter of the preovulatory follicle; (2) emergence of the future ovulatory follicle before the largest subordinate follicle; (3) a mean interval of 1 day between emergence of individual follicles of the wave; (4) percentage increase in diameter of follicles for the 3 days before deviation; (5) deviation 3 or 4 days after emergence; (6) 25% incidence of a major anovulatory follicular wave emerging before the ovulatory wave; (7) 40% incidence of a predeviation follicle preceding the ovulatory wave; (8) small but significant increase in estradiol and LH before deviation; (9) cooperative roles of FSH and insulin-like growth factor 1 and its proteases in the deviation process; (10) age-related effects on the follicles and oocytes; (11) approximate 37-hour interval between administration of hCG and ovulation; and (12) similar gray-scale and color-Doppler ultrasound changes in the preovulatory follicle. In conclusion, the mare may be the premier nonprimate model for study of follicle dynamics in women. Copyright © 2012 Elsevier Inc. All rights reserved.
Uterine and fetal dynamics during early pregnancy in mares.

PubMed

Griffin, P G; Ginther, O J

1991-02-01

Fetal activity and mobility and changes in diameter of the allantoic fluid compartment in the uterine horns were studied in mares between days 69 and 81 of pregnancy by use of transrectal ultrasonography (n = 12) and transcervical videoendoscopy (n = 8). The insertion tube of the videoendoscope was positioned within the allantoic sac to permit viewing of the fetus and entrance to each uterine horn. Each uterine horn was divided ultrasonographically into 3 segments of equal length, and the horns were designated on the basis of side of umbilical attachment (cord vs noncord horns). The diameter of the allantoic fluid compartment in the cornual segments increased (P less than 0.05) over the cranial (18.6 +/- 1.9 mm), middle (35.6 +/- 2.9 mm), and caudal (51.7 +/- 4.4 mm) segments, but differences between cord and noncord horns were not evident. Dynamic changes in diameter of the allantoic fluid compartment in cornual segments (ultrasonography) and at the entrance to each uterine horn (videoendoscopy) were detected (no significant difference between methods). During continuous videoendoscopic viewing (17 to 60 min/mare), extreme changes in allantoic fluid compartment diameter (76 to 100% of maximum to 0 to 25% of maximum or vice-versa) occurred an equivalent of 2.6 times/h/horn entrance; changes had an average duration of 3.4 minutes. A change from 100% (maximal diameter) to 0% (no visible lumen) or vice-versa occurred an equivalent of 1.3 times/h/horn entrance. Sometimes the uterine wall was so closely constricted++ around the fetal-amniotic unit that no intervening allantoic fluid was ultrasonographically detectable whereas at other times the uterus in the same location was widely dilated.(ABSTRACT TRUNCATED AT 250 WORDS)
Analysis of vestibular schwannoma size in multiple dimensions: a comparative cohort study of different measurement techniques.

PubMed

Varughese, J K; Wentzel-Larsen, T; Vassbotn, F; Moen, G; Lund-Johansen, M

2010-04-01

In this volumetric study of the vestibular schwannoma, we evaluated the accuracy and reliability of several approximation methods that are in use, and determined the minimum volume difference that needs to be measured for it to be attributable to an actual difference rather than a retest error. We also found empirical proportionality coefficients for the different methods. DESIGN/SETTING AND PARTICIPANTS: Methodological study with investigation of three different VS measurement methods compared to a reference method that was based on serial slice volume estimates. These volume estimates were based on: (i) one single diameter, (ii) three orthogonal diameters or (iii) the maximal slice area. Altogether 252 T1-weighted MRI images with gadolinium contrast, from 139 VS patients, were examined. The retest errors, in terms of relative percentages, were determined by undertaking repeated measurements on 63 scans for each method. Intraclass correlation coefficients were used to assess the agreement between each of the approximation methods and the reference method. The tendency for approximation methods to systematically overestimate/underestimate different-sized tumours was also assessed, with the help of Bland-Altman plots. The most commonly used approximation method, the maximum diameter, was the least reliable measurement method and has inherent weaknesses that need to be considered. This includes greater retest errors than area-based measurements (25% and 15%, respectively), and that it was the only approximation method that could not easily be converted into volumetric units. Area-based measurements can furthermore be more reliable for smaller volume differences than diameter-based measurements. All our findings suggest that the maximum diameter should not be used as an approximation method. We propose the use of measurement modalities that take into account growth in multiple dimensions instead.
In Vivo Voltage-Sensitive Dye Study of Lateral Spreading of Cortical Activity in Mouse Primary Visual Cortex Induced by a Current Impulse

PubMed Central

Fehérvári, Tamás Dávid; Sawai, Hajime; Yagi, Tetsuya

2015-01-01

In the mammalian primary visual cortex (V1), lateral spreading of excitatory potentials is believed to be involved in spatial integrative functions, but the underlying cortical mechanism is not well understood. Visually-evoked population-level responses have been shown to propagate beyond the V1 initial activation site in mouse, similar to higher mammals. Visually-evoked responses are, however, affected by neuronal circuits prior to V1 (retina, LGN), making the separate analysis of V1 difficult. Intracortical stimulation eliminates these initial processing steps. We used in vivo RH1691 voltage-sensitive dye (VSD) imaging and intracortical microstimulation in adult C57BL/6 mice to elucidate the spatiotemporal properties of population-level signal spreading in V1 cortical circuits. The evoked response was qualitatively similar to that measured in single-cell electrophysiological experiments in rodents: a fast transient fluorescence peak followed by a fast and a slow decrease or hyperpolarization, similar to EPSP and fast and slow IPSPs in single cells. The early cortical response expanded at speeds commensurate with long horizontal projections (at 5% of the peak maximum, 0.08–0.15 m/s) however, the bulk of the VSD signal propagated slowly (at half-peak maximum, 0.05–0.08 m/s) suggesting an important role of regenerative multisynaptic transmission through short horizontal connections in V1 spatial integrative functions. We also found a tendency for a widespread and fast cortical response suppression in V1, which was eliminated by GABAA-antagonists gabazine and bicuculline methiodide. Our results help understand the neuronal circuitry involved in lateral spreading in V1. PMID:26230520
Quasi-monoenergetic proton beam from a proton-layer embedded metal foil irradiated by an intense laser pulse

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

Kim, Kyung Nam; Lee, Kitae, E-mail: klee@kaeri.re.kr; Kumar, Manoj

A target structure, ion-layer embedded foil (ILEF) is proposed for producing a quasi-monoenergetic proton beam by utilizing a bulk electrostatic field, which is generated by irradiating the target with an ultra-intense laser pulse, inside the plasma. Compared with the case of a single metal foil in which the proton layer is initially present on the surface, in the ILEF target, the proton layer is initially located inside a metal foil. A two-dimensional particle-in-cell (PIC) simulation shows that the target generates a proton beam with a narrow energy spread. With a laser intensity of 2 × 10{sup 19 }W/cm{sup 2}, a 22-MeV proton beammore » with an energy spread of 8% at the full-width-half-maximum (FWHM) is obtained when the proton layer is located at 0.4 μm inside the rear surface of a 2.4 μm-thick copper foil. When the proton layer moves toward the front side, a proton beam with a flat-top energy distribution ranging from 15 MeV to 35 MeV is obtained. Further, with a higher laser intensity of 10{sup 21 }W/cm{sup 2}, a proton beam with the maximum energy of 345 MeV and FWHM energy spread of 7.2% is obtained. The analysis of the PIC simulation with an aid of a fluid analysis shows that the spectrum is affected by the initial position of the proton layer, its initial spread during the formation of the sheath field, and the space charge effect.« less
Simultaneous imaging of intrinsic optical signals and cerebral vessel responses during cortical spreading depression in rats

NASA Astrophysics Data System (ADS)

Li, Pengcheng; Chen, Shangbin; Luo, Weihua; Luo, Qingming

2003-12-01

Cortical spreading depression (CSD) is an important disease model for migraine and cerebral ischemia. We investigated the spatio-temporal characteristics of the intrinsic optical signals (IOS) at 570 nm and the cerebral blood vessel responses during CSD simultaneously by optical reflectance imaging in vivo. The CSD were induced by pinprick in 10 α-chloralose/urethane anesthetized Sprague-Dawley rats. A four-phasic IOS response was observed at pial arteries and parenchymal sites in all experimental animals and an initial slight pial arteries dilation (21.5%+/-13.6%) and constriction (-4.2%+/-3.5%) precedes the dramatic dilation (69.2%+/-26.1%) of pial arterioles was recorded. Our experimental results show a high correlation (r = 0.89+/-0.025) between the IOS response and the diameter changes of the cerebral blood vessels during CSD in rats.
Abnormal splenic artery diameter/hepatic artery diameter ratio in cirrhosis-induced portal hypertension

PubMed Central

Zeng, Dao-Bing; Dai, Chuan-Zhou; Lu, Shi-Chun; He, Ning; Wang, Wei; Li, Hong-Jun

2013-01-01

AIM: To determine an optimal cutoff value for abnormal splenic artery diameter/proper hepatic artery diameter (S/P) ratio in cirrhosis-induced portal hypertension. METHODS: Patients with cirrhosis and portal hypertension (n = 770) and healthy volunteers (n = 31) underwent volumetric computed tomography three-dimensional vascular reconstruction to measure the internal diameters of the splenic artery and proper hepatic artery to calculate the S/P ratio. The cutoff value for abnormal S/P ratio was determined using receiver operating characteristic curve analysis, and the prevalence of abnormal S/P ratio and associations between abnormal S/P ratio and major complications of portal hypertension were studied using logistic regression. RESULTS: The receiver operating characteristic analysis showed that the cutoff points for abnormal splenic artery internal diameter and S/P ratio were > 5.19 mm and > 1.40, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value were 74.2%, 45.2%, 97.1%, and 6.6%, respectively. The prevalence of an abnormal S/P ratio in the patients with cirrhosis and portal hypertension was 83.4%. Patients with a higher S/P ratio had a lower risk of developing ascites [odds ratio (OR) = 0.708, 95%CI: 0.508-0.986, P = 0.041] and a higher risk of developing esophageal and gastric varices (OR = 1.483, 95%CI: 1.010-2.175, P = 0.044) and forming collateral circulation (OR = 1.518, 95%CI: 1.033-2.230, P = 0.034). After splenectomy, the portal venous pressure and maximum and mean portal venous flow velocities were reduced, while the flow rate and maximum and minimum flow velocities of the hepatic artery were increased (P < 0.05). CONCLUSION: The prevalence of an abnormal S/P ratio is high in patients with cirrhosis and portal hypertension, and it can be used as an important marker of splanchnic hemodynamic disturbances. PMID:23483462
Wire Insulation Flammability Experiment: USML-1 One Year Post Mission Summary

NASA Technical Reports Server (NTRS)

Greenberg, Paul S.; Sacksteder, Kurt R.; Kashiwagi, Takashi

1994-01-01

Herein we report the results from the Wire Insulation Flammability (WIF) Experiment performed in the Glovebox Facility on the USML-1 mission. This experiment explored various aspects of electrically induced fire scenarios in a reduced gravity environment. Under quiescent microgravity conditions, heat and mass transfer are dominated by diffusive and radiative transport; while in normal-gravity buoyancy induced convection often dominates. Of considerable scientific and practical interest is the intermediate situation of combustion occurring in the presence of imposed gas flows, with lower characteristic velocities than those induced by buoyancy in noma1 gravity. Two distinct cases naturally arise: flow direction opposed to, or concurrent with, the flame spread direction. Two tests of each kind were conducted in the WIF experiment, providing the first controlled demonstration of flame spreading in forced convection ever conducted in space. Four test modules were flown. The wire insulation, 1.5 mm in diameter, was polyethylene, extruded onto nichrome wire. Temperatures of the wh3 cores and insulation heated in quiescent and flowing environments were measured. Video and still-camera images of the samples, burning in air flowing at approximately 10 cm/sec, were recorded to obtain flame characteristics including spread rate, structure and temperature. Flame spread rates in concurrent flow were approximately twice those in opposed flow. In concurrent and opposed flow regimes, the spreading flames stabilized around a bead of molten insulation material, within which bubble nucleation was observed. An ignition attempt without flow mated a quiescent cloud of vaporized fuel which ignited dramatically yet failed to sustain normal flame spread. Finally, all tests produced substantial soot agglomerates, particularly the concurrent flow tests; and the collected soot has a morphology very distinct from soot formed in normal gravity flames. Several unexpected and unique microgravity combustion phenomena were observed.
Microgravity Flame Spread in Exploration Atmospheres: Pressure, Oxygen, and Velocity Effects on Opposed and Concurrent Flame Spread

NASA Technical Reports Server (NTRS)

Olson, Sandra L.; Ruff, Gary A.; Fletcher, J. Miller

2008-01-01

Microgravity tests of flammability and flame spread were performed in a low-speed flow tunnel to simulate spacecraft ventilation flows. Three thin fuels were tested for flammability (Ultem 1000 (General Electric Company), 10 mil film, Nomex (Dupont) HT90-40, and Mylar G (Dupont) and one fuel for flame spread testing (Kimwipes (Kimberly-Clark Worldwide, Inc.). The 1g Upward Limiting Oxygen Index (ULOI) and 1g Maximum Oxygen Concentration (MOC) are found to be greater than those in 0g, by up to 4% oxygen mole fraction, meaning that the fuels burned in 0g at lower oxygen concentrations than they did using the NASA Standard 6001 Test 1 protocol. Flame spread tests with Kimwipes were used to develop correlations that capture the effects of flow velocity, oxygen concentration, and pressure on flame spread rate. These correlations were used to determine that over virtually the entire range of spacecraft atmospheres and flow conditions, the opposed spread is faster, especially for normoxic atmospheres. The correlations were also compared with 1g MOC for various materials as a function of pressure and oxygen. The lines of constant opposed flow agreed best with the 1g MOC trends, which indicates that Test 1 limits are essentially dictated by the critical heat flux for ignition. Further evaluation of these and other materials is continuing to better understand the 0g flammability of materials and its effect on the oxygen margin of safety.
Novel mathematical algorithm for pupillometric data analysis.

PubMed

Canver, Matthew C; Canver, Adam C; Revere, Karen E; Amado, Defne; Bennett, Jean; Chung, Daniel C

2014-01-01

Pupillometry is used clinically to evaluate retinal and optic nerve function by measuring pupillary response to light stimuli. We have developed a mathematical algorithm to automate and expedite the analysis of non-filtered, non-calculated pupillometric data obtained from mouse pupillary light reflex recordings, obtained from dynamic pupillary diameter recordings following exposure of varying light intensities. The non-filtered, non-calculated pupillometric data is filtered through a low pass finite impulse response (FIR) filter. Thresholding is used to remove data caused by eye blinking, loss of pupil tracking, and/or head movement. Twelve physiologically relevant parameters were extracted from the collected data: (1) baseline diameter, (2) minimum diameter, (3) response amplitude, (4) re-dilation amplitude, (5) percent of baseline diameter, (6) response time, (7) re-dilation time, (8) average constriction velocity, (9) average re-dilation velocity, (10) maximum constriction velocity, (11) maximum re-dilation velocity, and (12) onset latency. No significant differences were noted between parameters derived from algorithm calculated values and manually derived results (p ≥ 0.05). This mathematical algorithm will expedite endpoint data derivation and eliminate human error in the manual calculation of pupillometric parameters from non-filtered, non-calculated pupillometric values. Subsequently, these values can be used as reference metrics for characterizing the natural history of retinal disease. Furthermore, it will be instrumental in the assessment of functional visual recovery in humans and pre-clinical models of retinal degeneration and optic nerve disease following pharmacological or gene-based therapies. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
Large-scale production of kappa-carrageenan droplets for gel-bead production: theoretical and practical limitations of size and production rate.

PubMed

Hunik, J H; Tramper, J

1993-01-01

Immobilization of biocatalysts in kappa-carrageenan gel beads is a widely used technique nowadays. Several methods are used to produce the gel beads. The gel-bead production rate is usually sufficient to make the relatively small quantities needed for bench-scale experiments. The droplet diameter can, within limits, be adjusted to the desired size, but it is difficult to predict because of the non-Newtonian fluid behavior of the kappa-carrageenan solution. Here we present the further scale-up of the extrusion technique with the theory to predict the droplet diameters for non-Newtonian fluids. The emphasis is on the droplet formation, which is the rate-limiting step in this extrusion technique. Uniform droplets were formed by breaking up a capillary jet with a sinusoidal signal of a vibration exciter. At the maximum production rate of 27.6 dm3/h, uniform droplets with a diameter of (2.1 +/- 0.12) x 10(-3) m were obtained. This maximum flow rate was limited by the power transfer of the vibration exciter to the liquid flow. It was possible to get a good prediction of the droplet diameter by estimating the local viscosity from shear-rate calculations and an experimental relation between the shear rate and viscosity. In this way the theory of Newtonian fluids could be used for the non-Newtonian kappa-carrageenan solution. The calculated optimal break-up frequencies and droplet sizes were in good agreement with those found in the experiments.
Throughput of diffraction-limited field optics systems for infrared and millimetric telescopes

NASA Technical Reports Server (NTRS)

Hildebrand, R. H.; Winston, R.

1982-01-01

Telescopes for submillimeter wavelengths have point spread functions some millimeters or centimeters in diameter, but the detectors may be only fractions of a millimeter in size. Thus a field aperture and collecting optics are needed. Optimizing the aperture by a calculation of the effects of diffraction on signal and resolution as a function of size of the collecting aperture is shown. Calculations are compared to experimental results from observations of Mars at submillimeter wavelengths.
Single-bubble dynamics in pool boiling of one-component fluids.

PubMed

Xu, Xinpeng; Qian, Tiezheng

2014-06-01

We numerically investigate the pool boiling of one-component fluids with a focus on the effects of surface wettability on the single-bubble dynamics. We employed the dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007)], a diffuse-interface model for liquid-vapor flows involving liquid-vapor transition in nonuniform temperature fields. We first perform simulations for bubbles on homogeneous surfaces. We find that an increase in either the contact angle or the surface superheating can enhance the bubble spreading over the heating surface and increase the bubble departure diameter as well and therefore facilitate the transition into film boiling. We then examine the dynamics of bubbles on patterned surfaces, which incorporate the advantages of both hydrophobic and hydrophilic surfaces. The central hydrophobic region increases the thermodynamic probability of bubble nucleation while the surrounding hydrophilic region hinders the continuous bubble spreading by pinning the contact line at the hydrophobic-hydrophilic intersection. This leads to a small bubble departure diameter and therefore prevents the transition from nucleate boiling into film boiling. With the bubble nucleation probability increased and the bubble departure facilitated, the efficiency of heat transfer on such patterned surfaces is highly enhanced, as observed experimentally [Int. J. Heat Mass Transfer 57, 733 (2013)]. In addition, the stick-slip motion of contact line on patterned surfaces is demonstrated in one-component fluids, with the effect weakened by surface superheating.
DATA-DRIVEN DISCOVERY OF TEMPORAL AND GEOSPATIAL PATTERNS OF DISEASE TRANSMISSION: WEST NILE VIRUS IN MARYLAND

EPA Science Inventory

The necessity of rapid response to a developing disease outbreak often precludes systematic investigation of the mechanisms and patterns (temporal and geospatial) of spread. In order to deploy the most rapid response possible, we must exploit existing data to its maximum extent....
Effects of microstructure on water imbibition in sandstones using X-ray computed tomography and neutron radiography

NASA Astrophysics Data System (ADS)

Zhao, Yixin; Xue, Shanbin; Han, Songbai; Chen, Zhongwei; Liu, Shimin; Elsworth, Derek; He, Linfeng; Cai, Jianchao; Liu, Yuntao; Chen, Dongfeng

2017-07-01

Capillary imbibition in variably saturated porous media is important in defining displacement processes and transport in the vadose zone and in low-permeability barriers and reservoirs. Nonintrusive imaging in real time offers the potential to examine critical impacts of heterogeneity and surface properties on imbibition dynamics. Neutron radiography is applied as a powerful imaging tool to observe temporal changes in the spatial distribution of water in porous materials. We analyze water imbibition in both homogeneous and heterogeneous low-permeability sandstones. Dynamic observations of the advance of the imbibition front with time are compared with characterizations of microstructure (via high-resolution X-ray computed tomography (CT)), pore size distribution (Mercury Intrusion Porosimetry), and permeability of the contrasting samples. We use an automated method to detect the progress of wetting front with time and link this to square-root-of-time progress. These data are used to estimate the effect of microstructure on water sorptivity from a modified Lucas-Washburn equation. Moreover, a model is established to calculate the maximum capillary diameter by modifying the Hagen-Poiseuille and Young-Laplace equations based on fractal theory. Comparing the calculated maximum capillary diameter with the maximum pore diameter (from high-resolution CT) shows congruence between the two independent methods for the homogeneous silty sandstone but less effectively for the heterogeneous sandstone. Finally, we use these data to link observed response with the physical characteristics of the contrasting media—homogeneous versus heterogeneous—and to demonstrate the sensitivity of sorptivity expressly to tortuosity rather than porosity in low-permeability sandstones.
Image processing analysis of nuclear track parameters for CR-39 detector irradiated by thermal neutron

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

Al-Jobouri, Hussain A., E-mail: hahmed54@gmail.com; Rajab, Mustafa Y., E-mail: mostafaheete@gmail.com

CR-39 detector which covered with boric acid (H{sub 3}Bo{sub 3}) pellet was irradiated by thermal neutrons from ({sup 241}Am - {sup 9}Be) source with activity 12Ci and neutron flux 10{sup 5} n. cm{sup −2}. s{sup −1}. The irradiation times -T{sub D} for detector were 4h, 8h, 16h and 24h. Chemical etching solution for detector was sodium hydroxide NaOH, 6.25N with 45 min etching time and 60 C° temperature. Images of CR-39 detector after chemical etching were taken from digital camera which connected from optical microscope. MATLAB software version 7.0 was used to image processing. The outputs of image processing of MATLABmore » software were analyzed and found the following relationships: (a) The irradiation time -T{sub D} has behavior linear relationships with following nuclear track parameters: i) total track number - N{sub T} ii) maximum track number - MRD (relative to track diameter - D{sub T}) at response region range 2.5 µm to 4 µm iii) maximum track number - M{sub D} (without depending on track diameter - D{sub T}). (b) The irradiation time -T{sub D} has behavior logarithmic relationship with maximum track number - M{sub A} (without depending on track area - A{sub T}). The image processing technique principally track diameter - D{sub T} can be take into account to classification of α-particle emitters, In addition to the contribution of these technique in preparation of nano- filters and nano-membrane in nanotechnology fields.« less
Seasonal variation and principle of cyanobacterial biomass and forms in the water source area of Chaohu City, China

NASA Astrophysics Data System (ADS)

Xu, Xiangen; Ke, Fan; Li, Wenchao; Feng, Muhua; Shang, Lixia; Fan, Fan; He, Yanzhao

2016-01-01

We investigated seasonal variations in cyanobacterial biomass and the forms of its dominant population ( M. aeruginosa) and their correlation with environmental factors in the water source area of Chaohu City, China from December 2011 to October 2012. The results show that species belonging to the phylum Cyanophyta occupied the maximum proportion of phytoplankton biomass, and that the dominant population in the water source area of Chaohu City was M. aeruginosa. The variation in cyanobacterial biomass from March to August 2012 was well fitted to the logistic growth model. The growth rate of cyanobacteria was the highest in June, and the biomass of cyanobacteria reached a maximum in August. From February to March 2012, the main form of M. aeruginosa was the single-cell form; M. aeruginosa colonies began to appear from April, and blooms appeared on the water surface in May. The maximum diameter of the colonies was recorded in July, and then gradually decreased from August. The diameter range of M. aeruginosa colonies was 18.37-237.77 μm, and most of the colonies were distributed in the range 20-200 μm, comprising 95.5% of the total number of samples. Temperature and photosynthetically active radiation may be the most important factors that influenced the annual variation in M. aeruginosa biomass and forms. The suitable temperature for cyanobacterial growth was in the range of 15-30°C. In natural water bodies, photosynthetically active radiation had a significant positive influence on the colonial diameter of M. aeruginosa ( P <0.01).

Experimental Investigation of Eccentricity Ratio, Friction, and Oil Flow of Short Journal Bearings

NASA Technical Reports Server (NTRS)

Dubois, G B; Ocvirk, F W

1952-01-01

An experimental investigation was conducted to obtain performance data on bearings of length-diameter ratios of 1, 1/2, and 1/4 for comparison with theoretical curves. A 1.375-inch-diameter bearing was tested at speeds up to 6000 rpm and with unit loads from 0 to 900 pounds per square inch. Experimental data for eccentricity ratio and friction followed single lines when plotted against a theoretically derived capacity number, which is equal to Sommerfeld number times the square of the length-diameter ratio. The form of the capacity number indicates that under certain conditions the eccentricity ratio is theoretically independent of bearing diameter. A method of plotting oil flow data as a single line is shown. Methods are also discussed for approximating a maximum bearing temperature and evaluating the effect of deflection or misalignment on the eccentricity ratio at the ends of the bearings.
Determination of detonation parameters for liquid High Explosives

NASA Astrophysics Data System (ADS)

Mochalova, Valentina; Utkin, Alexander

2011-06-01

The experimental investigation of detonation parameters and reaction zone structure in liquid HE (bis-(2-fluoro-2,2-dinitroethyl)formal (FEFO), tetranitromethane (TNM), nitromethane (NM)) was conducted. Detonation front in TNM and NM was stable while the instability of detonation in FEFO was observed. Von Neumann spike was recorded for these HE and its parameters were determined. The different methods for C-J point determination were used for each HE. For FEFO reaction time τ was found from experiments with different charge diameters (τ is approximately equal to 300 ns); for TNM - at fixed diameter and different lengths of charges (τ ~ 200 ns); for NM - at fixed diameter and length of charges, but detonation initiation was carried out by different explosive charges (τ ~ 50 ns). It was found that in TNM the detonation velocity depends on charge diameter. Maximum value of reaction rate in investigated liquid HE was observed after shock jump and induction time was not recorded.
Determination of detonation parameters for liquid high explosives

NASA Astrophysics Data System (ADS)

Mochalova, Valentina; Utkin, Alexander

2012-03-01

The experimental investigation of detonation parameters and reaction zone structure in liquid HE (bis-(2-fluoro-2,2-dinitroethyl)formal (FEFO), tetranitromethane (TNM), nitromethane (NM)) was conducted by means of laser interferometer VISAR. Detonation front in TNM and NM was stable while the instability of detonation in FEFO was observed. The parameters of Von Neumann spike were determined for these HE. The different methods for C-J point determination were used for each HE. For FEFO reaction time t was found from experiments with different charge diameters (τ is approximately equal to 300 ns); for TNM - at fixed diameter and different lengths of charges (τ ≈ 200 ns); for NM - at fixed diameter and length of charges, but detonation initiation was carried out by different explosive charges (τ ≈ 50 ns). It was found that in TNM the detonation velocity depends on charge diameter. Maximum value of reaction rate in investigated liquid HE was observed after shock jump.
Undercuts by Laser Shock Forming

NASA Astrophysics Data System (ADS)

Wielage, Hanna; Vollertsen, Frank

2011-05-01

In laser shock forming TEA-CO2-laser induced shock waves are used to form metal foils, such as aluminum or copper. The process utilizes an initiated plasma shock wave on the target surface, which leads to a forming of the foil. A challenge in forming technologies is the manufacturing of undercuts. By conventional forming methods these special forms are not feasible. In this article, it is presented that undercuts in the micro range can be produced by laser shock deep drawing. Different drawing die diameters, drawing die depths and the material aluminum in the thicknesses 20 and 50 μm were investigated. It will be presented that smaller die diameters facilitate undercuts compared to bigger die diameters. The phenomena can be explained by Barlow's formula. Furthermore, it is shown which maximum undercut depth at different die diameters can be reached. To this end, cross-sections of the different parameter combinations are displayed.
Fabrication and electrical characterization of sub-micron diameter through-silicon via for heterogeneous three-dimensional integrated circuits

NASA Astrophysics Data System (ADS)

Abbaspour, R.; Brown, D. K.; Bakir, M. S.

2017-02-01

This paper presents the fabrication and electrical characterization of high aspect-ratio (AR) sub-micron diameter through silicon vias (TSVs) for densely interconnected three-dimensional (3D) stacked integrated circuits (ICs). The fabricated TSV technology features an AR of 16:1 with 680 nm diameter copper (Cu) core and 920 nm overall diameter. To address the challenges in scaling TSVs, scallop-free low roughness nano-Bosch silicon etching and direct Cu electroplating on a titanium-nitride (TiN) diffusion barrier layer have been developed as key enabling modules. The electrical resistance of the sub-micron TSVs is measured to be on average 1.2 Ω, and the Cu resistivity is extracted to be approximately 2.95 µΩ cm. Furthermore, the maximum achievable current-carrying capacity (CCC) of the scaled TSVs is characterized to be approximately 360 µA for the 680 nm Cu core.
Spherical Harmonic-based Random Fields Based on Real Particle 3D Data: Improved Numerical Algorithm and Quantitative Comparison to Real Particles

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

X Liu; E Garboczi; m Grigoriu

Many parameters affect the cyclone efficiency, and these parameters can have different effects in different flow regimes. Therefore the maximum-efficiency cyclone length is a function of the specific geometry and operating conditions in use. In this study, we obtained a relationship describing the minimum particle diameter or maximum cyclone efficiency by using a theoretical approach based on cyclone geometry and fluid properties. We have compared the empirical predictions with corresponding literature data and observed good agreement. The results address the importance of fluid properties. Inlet and vortex finder cross-sections, cone-apex diameter, inlet Reynolds number and surface roughness are found tomore » be the other important parameters affecting cyclone height. The surface friction coefficient, on the other hand, is difficult to employ in the calculations.We developed a theoretical approach to find the maximum-efficiency heights for cyclones with tangential inlet and we suggested a relation for this height as a function of cyclone geometry and operating parameters. In order to generalize use of the relation, two dimensionless parameters, namely for geometric and operational variables, we defined and results were presented in graphical form such that one can calculate and enter the values of these dimensionless parameters and then can find the maximum efficiency height of his own specific cyclone.« less
Pulsed and CW adjustable 1942 nm single-mode all-fiber Tm-doped fiber laser system for surgical laser soft tissue ablation applications.

PubMed

Huang, Yize; Jivraj, Jamil; Zhou, Jiaqi; Ramjist, Joel; Wong, Ronnie; Gu, Xijia; Yang, Victor X D

2016-07-25

A surgical laser soft tissue ablation system based on an adjustable 1942 nm single-mode all-fiber Tm-doped fiber laser operating in pulsed or CW mode with nitrogen assistance is demonstrated. Ex vivo ablation on soft tissue targets such as muscle (chicken breast) and spinal cord (porcine) with intact dura are performed at different ablation conditions to examine the relationship between the system parameters and ablation outcomes. The maximum laser average power is 14.4 W, and its maximum peak power is 133.1 W with 21.3 μJ pulse energy. The maximum CW power density is 2.33 × 10⁶ W/cm² and the maximum pulsed peak power density is 2.16 × 10⁷ W/cm². The system parameters examined include the average laser power in CW or pulsed operation mode, gain-switching frequency, total ablation exposure time, and the input gas flow rate. The ablation effects were measured by microscopy and optical coherence tomography (OCT) to evaluate the ablation depth, superficial heat-affected zone diameter (HAZD) and charring diameter (CD). Our results conclude that the system parameters can be tailored to meet different clinical requirements such as ablation for soft tissue cutting or thermal coagulation for future applications of hemostasis.
[Risk factor analysis of the patients with solitary pulmonary nodules and establishment of a prediction model for the probability of malignancy].

PubMed

Wang, X; Xu, Y H; Du, Z Y; Qian, Y J; Xu, Z H; Chen, R; Shi, M H

2018-02-23

Objective: This study aims to analyze the relationship among the clinical features, radiologic characteristics and pathological diagnosis in patients with solitary pulmonary nodules, and establish a prediction model for the probability of malignancy. Methods: Clinical data of 372 patients with solitary pulmonary nodules who underwent surgical resection with definite postoperative pathological diagnosis were retrospectively analyzed. In these cases, we collected clinical and radiologic features including gender, age, smoking history, history of tumor, family history of cancer, the location of lesion, ground-glass opacity, maximum diameter, calcification, vessel convergence sign, vacuole sign, pleural indentation, speculation and lobulation. The cases were divided to modeling group (268 cases) and validation group (104 cases). A new prediction model was established by logistic regression analying the data from modeling group. Then the data of validation group was planned to validate the efficiency of the new model, and was compared with three classical models(Mayo model, VA model and LiYun model). With the calculated probability values for each model from validation group, SPSS 22.0 was used to draw the receiver operating characteristic curve, to assess the predictive value of this new model. Results: 112 benign SPNs and 156 malignant SPNs were included in modeling group. Multivariable logistic regression analysis showed that gender, age, history of tumor, ground -glass opacity, maximum diameter, and speculation were independent predictors of malignancy in patients with SPN( P <0.05). We calculated a prediction model for the probability of malignancy as follow: p =e(x)/(1+ e(x)), x=-4.8029-0.743×gender+ 0.057×age+ 1.306×history of tumor+ 1.305×ground-glass opacity+ 0.051×maximum diameter+ 1.043×speculation. When the data of validation group was added to the four-mathematical prediction model, The area under the curve of our mathematical prediction model was 0.742, which is greater than other models (Mayo 0.696, VA 0.634, LiYun 0.681), while the differences between any two of the four models were not significant ( P >0.05). Conclusions: Age of patient, gender, history of tumor, ground-glass opacity, maximum diameter and speculation are independent predictors of malignancy in patients with solitary pulmonary nodule. This logistic regression prediction mathematic model is not inferior to those classical models in estimating the prognosis of SPNs.
Capillary spreading of contact line over a sinking sphere

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

Kim, Seong Jin; Fezzaa, Kamel; An, Jim

The contact line dynamics over a sinking solid sphere are investigated in comparison with classical spreading theories. Experimentally, high-speed imaging systems with optical light or x-ray illumination are employed to accurately measure the spreading motion and dynamic contact angle of the contact line. Millimetric spheres are controlled to descend with a constant speed ranging from 7.3 × 10-5 to 0.79 m/s. We observed three different spreading stages over a sinking sphere, which depends on the contact line velocity and contact angle. These stages consistently showed the characteristics of capillarity-driven spreading as the contact line spreads faster with a higher contactmore » angle. The contact line velocity is observed to follow a classical capillary-viscous model at a high Ohnesorge number (> 0.02). For the cases with a relatively low Ohnesorge number (< 0.02), the contact line velocity is significantly lower than the speed predicted by the capillary-viscous balance. This indicates the existence of an additional opposing force (inertia) for a decreasing Ohnesorge number. The capillary-inertial balance is only observed at the very beginning of the capillary rise, in which the maximum velocity is independent of the sphere’s sinking speed. Additionally, we observed the linear relation between the contact line velocity and the sphere sinking speed during the second stage, which represents capillary adjustment by dynamic contact angle.« less
Selective logging: does the imprint remain on tree structure and composition after 45 years?

PubMed

Osazuwa-Peters, Oyomoare L; Chapman, Colin A; Zanne, Amy E

2015-01-01

Selective logging of tropical forests is increasing in extent and intensity. The duration over which impacts of selective logging persist, however, remains an unresolved question, particularly for African forests. Here, we investigate the extent to which a past selective logging event continues to leave its imprint on different components of an East African forest 45 years later. We inventoried 2358 stems ≥10 cm in diameter in 26 plots (200 m × 10 m) within a 5.2 ha area in Kibale National Park, Uganda, in logged and unlogged forest. In these surveys, we characterized the forest light environment, taxonomic composition, functional trait composition using three traits (wood density, maximum height and maximum diameter) and forest structure based on three measures (stem density, total basal area and total above-ground biomass). In comparison to unlogged forests, selectively logged forest plots in Kibale National Park on average had higher light levels, different structure characterized by lower stem density, lower total basal area and lower above-ground biomass, and a distinct taxonomic composition driven primarily by changes in the relative abundance of species. Conversely, selectively logged forest plots were like unlogged plots in functional composition, having similar community-weighted mean values for wood density, maximum height and maximum diameter. This similarity in functional composition irrespective of logging history may be due to functional recovery of logged forest or background changes in functional attributes of unlogged forest. Despite the passage of 45 years, the legacy of selective logging on the tree community in Kibale National Park is still evident, as indicated by distinct taxonomic and structural composition and reduced carbon storage in logged forest compared with unlogged forest. The effects of selective logging are exerted via influences on tree demography rather than functional trait composition.
Selective logging: does the imprint remain on tree structure and composition after 45 years?

PubMed Central

Osazuwa-Peters, Oyomoare L.; Chapman, Colin A.; Zanne, Amy E.

2015-01-01

Selective logging of tropical forests is increasing in extent and intensity. The duration over which impacts of selective logging persist, however, remains an unresolved question, particularly for African forests. Here, we investigate the extent to which a past selective logging event continues to leave its imprint on different components of an East African forest 45 years later. We inventoried 2358 stems ≥10 cm in diameter in 26 plots (200 m × 10 m) within a 5.2 ha area in Kibale National Park, Uganda, in logged and unlogged forest. In these surveys, we characterized the forest light environment, taxonomic composition, functional trait composition using three traits (wood density, maximum height and maximum diameter) and forest structure based on three measures (stem density, total basal area and total above-ground biomass). In comparison to unlogged forests, selectively logged forest plots in Kibale National Park on average had higher light levels, different structure characterized by lower stem density, lower total basal area and lower above-ground biomass, and a distinct taxonomic composition driven primarily by changes in the relative abundance of species. Conversely, selectively logged forest plots were like unlogged plots in functional composition, having similar community-weighted mean values for wood density, maximum height and maximum diameter. This similarity in functional composition irrespective of logging history may be due to functional recovery of logged forest or background changes in functional attributes of unlogged forest. Despite the passage of 45 years, the legacy of selective logging on the tree community in Kibale National Park is still evident, as indicated by distinct taxonomic and structural composition and reduced carbon storage in logged forest compared with unlogged forest. The effects of selective logging are exerted via influences on tree demography rather than functional trait composition. PMID:27293697
Relationship between input power and power density of SMA spring

NASA Astrophysics Data System (ADS)

Park, Cheol Hoon; Ham, Sang Yong; Son, Young Su

2016-04-01

The important required characteristics of an artificial muscle for a human arm-like manipulator are high strain and high power density. From this viewpoint, an SMA (shape memory alloy) spring is a good candidate for the actuator of a robotic manipulator that utilizes an artificial muscle. In this study, the maximum power density of an SMA spring was evaluated with respect to the input power. The spring samples were fabricated from SMA wires of different diameters ranging between 0.1 and 0.3 mm. For each diameter, two types of wires with different transition temperatures were used. The relationship between the transition temperature and maximum power density was also evaluated. Each SMA spring was stretched downward by an attached weight and the temperature was increased through the application of an electric current. The displacement, velocity, and temperature of the SMA spring were measured by laser displacement sensors and a thermocouple. Based on the experimental data, it was determined that the maximum power densities of the different SMA springs ranged between 1,300 and 5,500 W/kg. This confirmed the applicability of an SMA spring to human arm-like robotic manipulators. The results of this study can be used as reference for design.
Design method of large-diameter rock-socketed pile with steel casing

NASA Astrophysics Data System (ADS)

Liu, Ming-wei; Fang, Fang; Liang, Yue

2018-02-01

There is a lack of the design and calculation method of large-diameter rock-socketed pile with steel casing. Combined with the “twelfth five-year plan” of the National Science & Technology Pillar Program of China about “Key technologies on the ports and wharfs constructions of the mountain canalization channels”, this paper put forward the structured design requirements of concrete, steel bar distribution and steel casing, and a checking calculation method of the bearing capacity of the normal section of the pile and the maximum crack width at the bottom of the steel casing. The design method will have some degree of guiding significance for the design of large-diameter rock-socketed pile with steel casing.
Using polycrystalline diamond-veined drills on silicon carbide particulate-reinforced aluminium castings

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

Lane, C.

1993-12-31

Using several combinations of speeds and feeds, a series of 6.37-mm diameter holes were drilled through a 19-mm thick plate of DURALCAN F3S.20S-T6 (A359/SiC/20p-T6). Every 50th hole was drilled in a gage block to measure the following: torque, thrust, drill flank wear, hole diameter, hole roundness, and hole surface finish. Maximum tool life was attained using feed rates of 0.25 mm/revolution. Speed had little effect on tool forces or life. Under optimum conditions, PCD-veined drills can produce over 6000 diameters of through holes in this type of composite with tolerances of 0.01 mm and flank wear of only 0.1 mm.
An experimental investigation of jet plume simulation with solid circular cylinders

NASA Technical Reports Server (NTRS)

Reubush, D. E.

1974-01-01

An investigation has been conducted in the Langley 16-foot transonic tunnel to determine the effectiveness of utilizing solid circular cylinders to simulate the jet exhaust plume for a series of four isolated circular arc afterbodies with little or no flow separation. This investigation was conducted at Mach numbers from 0.40 to 1.30 at 0 deg angle of attack. Plume simulators with simulator diameter to nozzle exit diameter ratios of 0.82, 0.88, 0.98, and 1.00 were investigated with one of the four configurations while the 0.82 and 1.00 simulators were investigated with the other three. Reynolds number based on maximum model diameter varied from approximately 1.50 to 2.14 million.
Suppression of the self-heating effect in GaN HEMT by few-layer graphene heat spreading elements

NASA Astrophysics Data System (ADS)

Volcheck, V. S.; Stempitsky, V. R.

2017-11-01

Self-heating has an adverse effect on characteristics of gallium nitride (GaN) high electron mobility transistors (HEMTs). Various solutions to the problem have been proposed, however, a temperature rise due to dissipated electrical power still hinders the production of high power and high speed GaN devices. In this paper, thermal management of GaN HEMT via few-layer graphene (FLG) heat spreading elements is investigated. It is shown that integration of the FLG elements on top of the device structure considerably reduces the maximum temperature and improves the DC and small signal AC performance.
Collapse displacements for a mechanism of spreading-induced supports in a masonry arch

NASA Astrophysics Data System (ADS)

Coccia, Simona; Di Carlo, Fabio; Rinaldi, Zila

2015-09-01

Masonry arch systems and vaulted structures constitute a structural typology widely spread in the historical building heritage. Small displacements of the supports, due to different causes, among which subsidence of foundation systems or movements of underlying structures can lead the masonry arch to a condition of collapse because of gradual change in its geometry. This paper presents a tool, based on a kinematic approach, for the computation of the magnitude of the displacements that cause the collapse of circular arches subject to dead loads, and allows the evaluation of the related thrust value. A parametric study has been carried out in order to develop a deeper understanding of the influence of the involved parameters. In addition, analytic formulations of the maximum allowed displacement and the associated thrust are proposed. Finally, a case study related to the behavior of a masonry arch on spreading-induced abutments is undertaken and discussed.
Spreading of correlations in the Falicov-Kimball model

NASA Astrophysics Data System (ADS)

Herrmann, Andreas J.; Antipov, Andrey E.; Werner, Philipp

2018-04-01

We study dynamical properties of the one- and two-dimensional Falicov-Kimball model using lattice Monte Carlo simulations. In particular, we calculate the spreading of charge correlations in the equilibrium model and after an interaction quench. The results show a reduction of the light-cone velocity with interaction strength at low temperature, while the phase velocity increases. At higher temperature, the initial spreading is determined by the Fermi velocity of the noninteracting system and the maximum range of the correlations decreases with increasing interaction strength. Charge order correlations in the disorder potential enhance the range of the correlations. We also use the numerically exact lattice Monte Carlo results to benchmark the accuracy of equilibrium and nonequilibrium dynamical cluster approximation calculations. It is shown that the bias introduced by the mapping to a periodized cluster is substantial, and that from a numerical point of view, it is more efficient to simulate the lattice model directly.
Effects of viscoelasticity on drop impact and spreading on a solid surface

NASA Astrophysics Data System (ADS)

Izbassarov, Daulet; Muradoglu, Metin

2016-06-01

The effects of viscoelasticity on drop impact and spreading on a flat solid surface are studied computationally using a finite-difference-front-tracking method. The finitely extensible nonlinear elastic-Chilcott-Rallison model is used to account for the fluid viscoelasticity. It is found that viscoelasticity favors advancement of contact line during the spreading phase, leading to a slight increase in the maximum spreading, in agreement with experimental observations [Huh, Jung, Seo, and Lee, Microfluid. Nanofluid. 18, 1221 (2015), 10.1007/s10404-014-1518-4]. However, in contrast with the well-known antirebound effects of polymeric additives, the viscoelasticity is found to enhance the tendency of the drop rebound in the receding phase. These results suggest that the antirebound effects are mainly due to the polymer-induced modification of wetting properties of the substrate rather than the change in the material properties of the drop fluid. A model is proposed to test this hypothesis. It is found that the model results in good qualitative agreement with the experimental observations and the antirebound behavior can be captured by the modification of surface wetting properties in the receding phase.
Suppressing epidemic spreading by risk-averse migration in dynamical networks

NASA Astrophysics Data System (ADS)

Yang, Han-Xin; Tang, Ming; Wang, Zhen

2018-01-01

In this paper, we study the interplay between individual behaviors and epidemic spreading in a dynamical network. We distribute agents on a square-shaped region with periodic boundary conditions. Every agent is regarded as a node of the network and a wireless link is established between two agents if their geographical distance is less than a certain radius. At each time, every agent assesses the epidemic situation and make decisions on whether it should stay in or leave its current place. An agent will leave its current place with a speed if the number of infected neighbors reaches or exceeds a critical value E. Owing to the movement of agents, the network's structure is dynamical. Interestingly, we find that there exists an optimal value of E leading to the maximum epidemic threshold. This means that epidemic spreading can be effectively controlled by risk-averse migration. Besides, we find that the epidemic threshold increases as the recovering rate increases, decreases as the contact radius increases, and is maximized by an optimal moving speed. Our findings offer a deeper understanding of epidemic spreading in dynamical networks.

Piezoelectric ultrasonic micromotor with 1.5 mm diameter.

PubMed

Dong, Shuxiang; Lim, Siak P; Lee, Kwork H; Zhang, Jingdong; Lim, Leong C; Uchino, Kenji

2003-04-01

A piezoelectric ultrasonic micromotor has been developed using a lead zirconate titanate (PZT) ceramic/metal composite tube stator that was 1.5 mm in diameter and 7 mm in length. The micromotor was operated in its first bending vibration mode (approximately 70 kHz), producing speeds from hundreds to over 2000 rpm in both rotational directions. The maximum torque-output was 45 microN-m, which is far superior to previous PZT thin film-based micromotors. This micromotor showed good reliability and stability for more than 300 hours of continued operation.
Dust Cloud Modeling and Propagation Effects for Radar and Communications Codes

DTIC Science & Technology

1978-11-01

particles can be described by a power law probabi 1it Y d i st r i ut i on with a power exponent of 4. Four is a typical value for dust particlIs from...loose unconsolidated soils such as desert alluviun, blust ,eera ted from a nuclear cratering explosion in rock and cohes ive soil s haN pO,,e r exponent ...da p = power law exponent amin = minimum particle diameter in the distribution (cm) a = maximum particle diameter in the distribution (cm).max The log
Wetting Behavior of Calcium Ferrite Slags on Cristobalite Substrates

NASA Astrophysics Data System (ADS)

Yang, Mingrui; Lv, Xuewei; Wei, Ruirui; Xu, Jian; Bai, Chenguang

2018-03-01

Calcium ferrite (CF) is a significant intermediate adhesive phase in high-basicity sinters. The wettability between calcium ferrite (CF) and gangue plays an important role in the assimilation process. The wettability of CF-based slags, in which a constant amount (2 mass pct.) of Al2O3, MgO, SiO2, and TiO2 was added, on solid SiO2 (cristobalite) substrates at 1523 K (1250 °C) was investigated. The interfacial microstructure and spreading mechanisms were discussed for each sample. All the tested slag samples exhibited good wettability on the SiO2 substrate. The initial apparent contact angles were in the range of 20 to 50 deg, while the final apparent contact angles were 5 deg. The wetting process could be divided into three stages on the basis of the change in diameter, namely the "linear spreading" stage, "spreading rate reduction" stage, and "wetting equilibrium" stage. It was found that the CF-SiO2 wetting system exhibits dissolutive wetting and the dissolution of SiO2 into slag influences its spreading process. The spreading rate increases with a decrease in the ratio of viscosity to interfacial tension, which is a result of the addition of Al2O3, MgO, SiO2, and TiO2. After cooling, a deep corrosion pit was formed in the substrate and a diffusion layer was generated in front of the residual slag zone; further, some SiO2 and Fe2O3 solid solutions precipitated in the slag.
Wetting Behavior of Calcium Ferrite Slags on Cristobalite Substrates

NASA Astrophysics Data System (ADS)

Yang, Mingrui; Lv, Xuewei; Wei, Ruirui; Xu, Jian; Bai, Chenguang

2018-06-01

Calcium ferrite (CF) is a significant intermediate adhesive phase in high-basicity sinters. The wettability between calcium ferrite (CF) and gangue plays an important role in the assimilation process. The wettability of CF-based slags, in which a constant amount (2 mass pct.) of Al2O3, MgO, SiO2, and TiO2 was added, on solid SiO2 (cristobalite) substrates at 1523 K (1250 °C) was investigated. The interfacial microstructure and spreading mechanisms were discussed for each sample. All the tested slag samples exhibited good wettability on the SiO2 substrate. The initial apparent contact angles were in the range of 20 to 50 deg, while the final apparent contact angles were 5 deg. The wetting process could be divided into three stages on the basis of the change in diameter, namely the "linear spreading" stage, "spreading rate reduction" stage, and "wetting equilibrium" stage. It was found that the CF-SiO2 wetting system exhibits dissolutive wetting and the dissolution of SiO2 into slag influences its spreading process. The spreading rate increases with a decrease in the ratio of viscosity to interfacial tension, which is a result of the addition of Al2O3, MgO, SiO2, and TiO2. After cooling, a deep corrosion pit was formed in the substrate and a diffusion layer was generated in front of the residual slag zone; further, some SiO2 and Fe2O3 solid solutions precipitated in the slag.
Buoyant Effects on the Flammability of Silicone Samples Planned for the Spacecraft Fire Experiment (Saffire)

NASA Technical Reports Server (NTRS)

Niehaus, Justin E.; Ferkul, Paul V.; Gokoglu, Suleyman A.; Ruff, Gary A.

2015-01-01

Flammability experiments on silicone samples were conducted in anticipation of the Spacecraft Fire Experiment (Saffire). The sample geometry was chosen to match the NASA 6001 Test 1 specification, namely 5 cm wide by 30 cm tall. Four thicknesses of silicone (0.25, 0.36, 0.61 and 1.00 mm) were examined. Tests included traditional upward buoyant flame spread using Test 1 procedures, downward opposed-flow flame spread, horizontal and angled flame spread, and forced-flow upward and downward flame spread. In addition to these configurations, upward and downward tests were conducted in a chamber with varying oxygen concentrations. In the upward buoyant flame spread tests, the flame generally did not burn the entire sample. As thickness was increased, the flame spread distance decreased before flame extinguishment. For the thickest sample, ignition could not be achieved. In the downward tests, the two thinnest samples permitted the flame to burn the entire sample, but the spread rate was lower compared to the corresponding upward values. The other two thicknesses could not be ignited in the downward configuration. The increased flammability for downward spreading flames relative to upward ones is uncommon. The two thinnest samples also burned completely in the horizontal configuration, as well as at angles up to 75 degrees from the horizontal. Upward tests in air with an added forced flow were more flammable. The upward and downward flammability behavior was compared in atmospheres of varying oxygen concentration to determine a maximum oxygen concentration for each configuration. Complementary analyses using EDS, TGA, and SEM techniques suggest the importance of the silica layer deposited downstream onto the unburned sample surface.
Volcanism and massive sulfide formation at a sedimented spreading center, Escanaba Trough, Gorda Ridge, northeast Pacific.

USGS Publications Warehouse

Morton, J.L.; Holmes, M.L.; Koski, R.A.

1987-01-01

Seismic-reflection profiles over the sediment-filled Escanaba Trough at the southern Gorda Ridge reveal a series of volcanic centers that pierce the sediment. The volcanic edifices are 3 to 6 km in diameter and are spaced at 15 to 20 km intervals along the axis of the trough. Composition and form of sulfide samples obtained from the bank suggest significant interaction between hydrothermal fluids and sediment at depth, and deposition of sulfide within the sediment pile.-from Authors
KSC-2012-6410

NASA Image and Video Library

2012-10-29

CAPE CANAVERAL, Fla. – At NASA’s Kennedy Space Center in Florida, workers pour and spread concrete at the base of the site of the Antenna Test Bed Array for the Ka-Band Objects Observation and Monitoring, Ka-BOOM system. The construction site is near the former Vertical Processing Facility, which has been demolished. Workers are placing the pile foundations for the 40-foot-diameter dish antenna arrays and their associated utilities, and preparing the site for the operations command center facility. Photo credit: NASA/Ben Smegelski
USB flow characteristics related to noise generation

NASA Technical Reports Server (NTRS)

Brown, W. H.; Reddy, N. N.

1976-01-01

The effects of nozzle and flap geometry on upper surface blown flow field characteristics related to noise generation were examined experimentally using static models. Flow attachment and spreading characteristics were observed using flow visualization techniques. Velocity and turbulence profiles in the trailing edge wake were measured using hot-wire anemometry, and the effects of the geometric variables on peak velocity and turbulence intensity were determined. It is shown that peak trailing edge velocity is a function of the ratio of flow length to modified hydraulic diameter.
Retrograde spread of 5-aminosalicylic acid enemas in patients with active ulcerative colitis

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

Campieri, M.; Lanfranchi, G.A.; Brignola, C.

1986-02-01

In an attempt to know the exact retrograde spread of high-dosage 5-aminosalicylic acid enemas, we have studied eight patients with active left-sided colitis, by adding a small amount of barium sulfate to the enemas and by checking the spread radiologically after 15 minutes, 1 hour, and 6 hours. Four grams of 5-aminosalicylic acid in 100-ml enemas and 4 gm in 200-ml enemas were used. The same experiment was repeated in a subsequent attack, with enemas labeled with technetium-99m and checked by scintiscans in five of these patients. We always have observed a volume-dependent spread of enemas but, interestingly, in themore » patients studied with technetium-99m there was always a wider spread than that which was detected with barium enemas. In all five patients, 100-ml enemas reached the splenic flexure. In two patients with total colitis, a progression of 100-ml technetium-99m enemas was performed in the transverse colon, but the maximum opacity remained in the left side. We can conclude that 4 gm of 5-aminosalicylic acid in 100-ml enemas can be suitable for treating patients with left-sided colitis, and will represent a valid addition for patients with more extensive colitis.« less
Ad-Hoc Sensor Networks for Maritime Interdiction Operations and Regional Security

DTIC Science & Technology

2012-09-01

as resistant to rough sea conditions as the SHARC, since its maximum operation limit is sea state 3. Its maximum speed approaches three knots and...which renders it corrosion resistant and lightweight. Its length is 3.2 meters with a rotor diameter at 3.3 meters. It flies at speeds of 50 knots...NMIOTC main building and to a moored training ship (see Figure 50), (2) GSM/GPRS was networked with swimmers , (3) security patrol and target vessels
SU-E-T-98: An Analysis of TG-51 Electron Beam Calibration Correction Factor Uncertainty

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

Lee, P; Alvarez, P; Taylor, P

Purpose: To analyze the uncertainty of the TG-51 electron beam calibration correction factors for farmer type ion chambers currently used by institutions visited by IROC Houston. Methods: TG-51 calibration data were collected from 181 institutions visited by IROC Houston physicists for 1174 and 197 distinct electron beams from modern Varian and Elekta accelerators, respectively. Data collected and analyzed included ion chamber make and model, nominal energy, N{sub D,w}, I{sub 50}, R{sub 50}, k’R{sub 50}, d{sub ref}, P{sub gr} and pdd(d{sub ref}). k’R{sub 50} data for parallel plate chambers were excluded from the analysis. Results: Unlike photon beams, electron nominal energymore » is a poor indicator of the actual energy as evidenced by the range of R{sub 50} values for each electron beam energy (6–22MeV). The large range in R{sub 50} values resulted k’R{sub 50} values with a small standard deviation but large range between maximum value used and minimum value (0.001–0.029) used for a specific Varian nominal energy. Varian data showed more variability in k’R{sub 50} values than the Elekta data (0.001–0.014). Using the observed range of R{sub 50} values, the maximum spread in k’R{sub 50} values was determined by IROC Houston and compared to the spread of k’R{sub 50} values used in the community. For Elekta linacs the spreads were equivalent, but for Varian energies of 6 to 16MeV, the community spread was 2 to 6 times larger. Community P{sub gr} values had a much larger range of values for 6 and 9 MeV values than predicted. The range in Varian pdd(d{sub ref} ) used by the community for low energies was large, (1.4–4.9 percent), when it should have been very close to unity. Exradin, PTW Roos and PTW farmer chambers N{sub D,w} values showed the largest spread, ≥11 percent. Conclusion: While the vast majority of electron beam calibration correction factors used are accurate, there is a surprising spread in some of the values used.« less
Spin Polarization and Quantum Spins in Au Nanoparticles

PubMed Central

Li, Chi-Yen; Karna, Sunil K.; Wang, Chin-Wei; Li, Wen-Hsien

2013-01-01

The present study focuses on investigating the magnetic properties and the critical particle size for developing sizable spontaneous magnetic moment of bare Au nanoparticles. Seven sets of bare Au nanoparticle assemblies, with diameters from 3.5 to 17.5 nm, were fabricated with the gas condensation method. Line profiles of the X-ray diffraction peaks were used to determine the mean particle diameters and size distributions of the nanoparticle assemblies. The magnetization curves M(Ha) reveal Langevin field profiles. Magnetic hysteresis was clearly revealed in the low field regime even at 300 K. Contributions to the magnetization from different size particles in the nanoparticle assemblies were considered when analyzing the M(Ha) curves. The results show that the maximum particle moment will appear in 2.4 nm Au particles. A similar result of the maximum saturation magnetization appearing in 2.3 nm Au particles is also concluded through analysis of the dependency of the saturation magnetization MP on particle size. The MP(d) curve departs significantly from the 1/d dependence, but can be described by a log-normal function. Magnetization can be barely detected for Au particles larger than 27 nm. Magnetic field induced Zeeman magnetization from the quantum confined Kubo gap opening appears in Au nanoparticles smaller than 9.5 nm in diameter. PMID:23989607
Comparison of CDMA and FDMA for the MobileStar(sm) system

NASA Technical Reports Server (NTRS)

Jacobs, I. M.; Gilhousen, K. S.; Weaver, L. A.; Renshaw, K.; Murphy, T.

1988-01-01

Spread-spectrum code division multiple access (CDMA) and single channel per carrier frequency division multiple access (FDMA) systems are compared for spectrum efficiency. CDMA is shown to have greater maximum throughput than FDMA for the MobileStar(sm) system which uses digital voice activated carriers and directive circularly polarized satellite antennas.
Wettability and impact dynamics of water droplets on rice ( Oryza sativa L.) leaves

NASA Astrophysics Data System (ADS)

Kwon, Dae Hee; Huh, Hyung Kyu; Lee, Sang Joon

2014-03-01

We investigated the wettability and impact dynamics of water droplets on rice leaves at various leaf inclination angles and orientations. Contact angle, contact angle hysteresis (CAH), and roll-off angle ( α roll) of water droplets were measured quantitatively. Results showed that droplet motion exhibited less resistance along the longitudinal direction. Impact dynamic parameters, such as impact behaviors, maximum spreading factor, contact distance, and contact time were also investigated. Three different impact behaviors were categorized based on the normal component of Weber number irrespective of the inclination angle of the rice leaf. The asymmetric impact behavior induced by the tangential Weber number was also identified. Variation in the maximum spreading factor according to the normal Weber number was measured and compared with theoretical value obtained according to scaling law to show the wettability of the rice leaves. The contact distance of the impacting droplets depended on the inclination angle of the leaves. Along the longitudinal direction of rice leaves, contact distance was farther than that along the transverse direction. This result is consistent with the smaller values of CAH and α roll along the longitudinal direction.
Evaluation of the Separability of Monodisperse Polystyrene Latex Microspheres in a Continuous Flow Electrophoresis System

NASA Technical Reports Server (NTRS)

Williams, G., Jr.

1983-01-01

The continuous flow electrophoresis system makes electrophoresis possible in a free flowing film of aqueous electrolyte medium. The sample is introduced at one end of the chamber and is subjected to a lateral dc field. This process separates the sample into fractions since each component has a distinctive electrophoric mobility. Evaluations were made of sample conductivity and buffer conductivity as they affect sample band spread and separation using the Continuous Particle Electrophoresis (CPE) system. Samples were prepared from mixtures of 5 percent and 1 percent polystyrene latex (PSL) microspheres which were .4, .56 and .7 microns in diameter. These were prepared in electrolyte media 1x and 3x the conductivity of the curtain buffer, approximately 150 and 450 micro mhos/cm. Samples with matched conductivities produced greater resolution and less band spread than those with 3x the conductivity of the curtain buffer.
Signal detection theory and vestibular perception: III. Estimating unbiased fit parameters for psychometric functions.

PubMed

Chaudhuri, Shomesh E; Merfeld, Daniel M

2013-03-01

Psychophysics generally relies on estimating a subject's ability to perform a specific task as a function of an observed stimulus. For threshold studies, the fitted functions are called psychometric functions. While fitting psychometric functions to data acquired using adaptive sampling procedures (e.g., "staircase" procedures), investigators have encountered a bias in the spread ("slope" or "threshold") parameter that has been attributed to the serial dependency of the adaptive data. Using simulations, we confirm this bias for cumulative Gaussian parametric maximum likelihood fits on data collected via adaptive sampling procedures, and then present a bias-reduced maximum likelihood fit that substantially reduces the bias without reducing the precision of the spread parameter estimate and without reducing the accuracy or precision of the other fit parameters. As a separate topic, we explain how to implement this bias reduction technique using generalized linear model fits as well as other numeric maximum likelihood techniques such as the Nelder-Mead simplex. We then provide a comparison of the iterative bootstrap and observed information matrix techniques for estimating parameter fit variance from adaptive sampling procedure data sets. The iterative bootstrap technique is shown to be slightly more accurate; however, the observed information technique executes in a small fraction (0.005 %) of the time required by the iterative bootstrap technique, which is an advantage when a real-time estimate of parameter fit variance is required.
78 FR 30391 - Notice of Applications for Modification of Special Permits

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-22

... diameter of 1-\\1/ 2\\ inches maximum for 4131 seamless steel tubing cylinder. 10704-M Air Liquide America 49... with CGA Pamphlet C-23. 12122-M ARC Automotive, Inc., 49 CFR 173.301(h), To modify the and special...
78 FR 66914 - Notice of Preliminary Permit Application Accepted for Filing and Soliciting Comments, Motions To...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-07

... upper reservoir having a total/usable storage capacity of 5,399 acre-feet at normal maximum operation... penstocks connecting the upper reservoir to the Pacific Ocean; (4) a 500-foot-long, 250-foot-diameter...
Strain Partitioning and Accumulation across Overlapping Spreading Centers: Geodetic GPS Measurements in South Iceland

NASA Astrophysics Data System (ADS)

La Femina, P. C.; Dixon, T. H.; Malservisi, R.; Árnadóttir, T.; Sigmundsson, F.; Sturkell, E.

2004-12-01

Overlapping spreading centers (OSCs) and propagating ridges are important classes of mid-ocean ridges. Kinematic models of OSCs predict along strike variability in spreading rate associated with the propagation of one center and deactivation of the other. Iceland offers a unique opportunity to investigate strain accumulation and partitioning across slow, overlapping spreading centers, and the influence of a ridge centered hotspot on ridge kinematics and morphology. We present results of detailed GPS observations across the Eastern and Western Volcanic Zones, south Iceland, spanning a seven to nine year inter-rifting period, and compare our observations with two-dimensional elastic half-space models that simulate the long-term spreading process. We then compare the elastic half-space models with simple viscoelastic coupling models. We model three velocity profiles across the EVZ-WVZ system, solving for the spreading rate, locking depth and horizontal location of each spreading center. Our spreading rate estimates indicate along strike variations as expected in an OSC system and total spreading rates consistent with geodetic and geologic plate motion models. Spreading rates in the WVZ increase from northeast (3 ±1 mm/yr) to southwest (7 ±1 mm/yr). Spreading rates in the southwest propagating EVZ decrease from northeast (17 ±1 mm/yr) to southwest (12 ±1 mm/yr). These results are consistent with a model whereby the WVZ is deactivating in the direction of EVZ propagation. The morphology of the two spreading centers reflects the spreading rate differences and their location relative to the Iceland hotspot. The predicted locations of the spreading axis for each zone are consistent with mapped Holocene fissure swarms. The neovolcanic zone of the slower WVZ consists of a narrow (10-20 km wide) axial graben and has had few Holocene eruptions. The faster EVZ consists of two parallel neovolcanic zones separated by a 20 km gap of inactivity, little normal faulting, higher topography and five historical fissure eruptions, reflecting its proximity to the hotspot. The maximum velocity gradient in the EVZ is located on the Veidivotn fissure swarm, which had a small volume eruption in 1864. The last major fissure eruption in the EVZ was the 1783 Lakagigar, located 20 km to the east. This pattern of current and past strain accumulation and release suggests intra-ridge jumping of activity and crustal accretion across a 60 km wide area.
Molten thermoplastic dripping behavior induced by flame spread over wire insulation under overload currents.

PubMed

He, Hao; Zhang, Qixing; Tu, Ran; Zhao, Luyao; Liu, Jia; Zhang, Yongming

2016-12-15

The dripping behavior of the molten thermoplastic insulation of copper wire, induced by flame spread under overload currents, was investigated for a better understanding of energized electrical wire fires. Three types of sample wire, with the same polyethylene insulation thickness and different core diameters, were used in this study. First, overload current effects on the transient one-dimensional wire temperature profile were predicted using simplified theoretical analysis; the heating process and equilibrium temperature were obtained. Second, experiments on the melting characteristics were conducted in a laboratory environment, including drop formation and frequency, falling speed, and combustion on the steel base. Third, a relationship between molten mass loss and volume variation was proposed to evaluate the dripping time and frequency. A strong current was a prerequisite for the wire dripping behavior and the averaged dripping frequency was found to be proportional to the square of the current based on the theoretical and experimental results. Finally, the influence of dripping behavior on the flame propagation along the energized electrical wire was discussed. The flame width, bright flame height and flame spreading velocity presented different behaviors. Copyright © 2016 Elsevier B.V. All rights reserved.

Monitoring of Time-Dependent System Profiles by Multiplex Gas Chromatography with Maximum Entropy Demodulation

NASA Technical Reports Server (NTRS)

Becker, Joseph F.; Valentin, Jose

1996-01-01

The maximum entropy technique was successfully applied to the deconvolution of overlapped chromatographic peaks. An algorithm was written in which the chromatogram was represented as a vector of sample concentrations multiplied by a peak shape matrix. Simulation results demonstrated that there is a trade off between the detector noise and peak resolution in the sense that an increase of the noise level reduced the peak separation that could be recovered by the maximum entropy method. Real data originated from a sample storage column was also deconvoluted using maximum entropy. Deconvolution is useful in this type of system because the conservation of time dependent profiles depends on the band spreading processes in the chromatographic column, which might smooth out the finer details in the concentration profile. The method was also applied to the deconvolution of previously interpretted Pioneer Venus chromatograms. It was found in this case that the correct choice of peak shape function was critical to the sensitivity of maximum entropy in the reconstruction of these chromatograms.
Mechanical properties and micro-morphology of fiber posts.

PubMed

Zicari, F; Coutinho, E; Scotti, R; Van Meerbeek, B; Naert, I

2013-04-01

To evaluate flexural properties of different fiber posts systems and to morphologically characterize their micro-structure. Six types of translucent fiber posts were selected: RelyX Post (3M ESPE), ParaPost Taper Lux (Colthéne-Whaledent), GC Fiber Post (GC), LuxaPost (DMG), FRC Postec Plus (Ivoclar-Vivadent), D.T. Light-Post (RTD). For each post system and size, ten specimens were subjected to a three-points bending test. Maximum fracture load, flexural strength and flexural modulus were determined using a universal loading device (5848 MicroTester(®), Instron). Besides, for each system, three intact posts of similar dimensions were processed for scanning electron microscopy to morphologically characterize the micro-structure. The following structural characteristics were analyzed: fibers/matrix ratio, density of fibers, diameter of fibers and distribution of fibers. Data were statistically analyzed with ANOVA. Type and diameter of posts were found to significantly affect the fracture load, flexural strength and flexural modulus (p<0.05). Regarding maximum fracture load, it was found to increase with post diameter, in each post system (p<0.001). Regarding flexural strength and flexural modulus, the highest values were recorded for posts with the smallest diameter (p<0.001). Finally, structural characteristics significantly varied among the post systems tested. However, any correlation has been found between flexural strength and structural characteristics. Flexural strength appeared not to be correlated to structural characteristics of fiber posts, but it may rather be affected by mechanical properties of the resin matrix and the interfacial adhesion between fibers and resin matrix. Copyright © 2013. Published by Elsevier Ltd.
The application of "natural" growth rates of Heterostegina depressa to infer timing of reproduction events

NASA Astrophysics Data System (ADS)

Eder, Wolfgang; Julia, Woeger; Kinoshita, Shunichi; Hohenegger, Johann; Briguglio, Antonino

2017-04-01

To explore applicability of the natural laboratory approach (sensu Hohenegger) on population dynamic studies of recent larger benthic foraminifera, this relatively new experimental method has been applied on Heterostegina depressa populations from Sesoko Jima, NW Okinawa, Japan. It is used to gain an averaged chamber and diameter building rate, as well as the average longevity of H. depressa based on monthly samplings at fixed sampling stations. Samples were collected by SCUBA in 16 monthly intervals around 20 and 50 meters water depth, wherefrom live populations were dried and investigated by microCT. The specimens were measured regarding chamber number and maximum diameter. This biometric data has been tested for the presence of multiple generations of H. depressa megalospheres. In case of skewed or bimodal frequency distributions, they were decomposed into normally distributed components. Means and standard deviations of each component of every month were extracted and could be used to calculate the maximum values of chamber number and diameter for all sampling intervals. Based on these maximal values, the natural chamber/diameter growth rate was fitted by Michaelis-Menten functions. By inversion of this growth functions the birthdate of every specimen was calculated. Frequency diagrams of these dates reveal a continuous background reproduction throughout the year, yet show distinct reproduction peaks in late spring and late autumn. Further, sinusoidal regression analysis support these two main reproduction cycles, one short-term cycle 70 days and a one long-term cycles around 180 days. Surprisingly, similar cycles have been found in different studies on volumetric growth of larger benthic foraminifera.
Standardized volume rendering for magnetic resonance angiography measurements in the abdominal aorta.

PubMed

Persson, A; Brismar, T B; Lundström, C; Dahlström, N; Othberg, F; Smedby, O

2006-03-01

To compare three methods for standardizing volume rendering technique (VRT) protocols by studying aortic diameter measurements in magnetic resonance angiography (MRA) datasets. Datasets from 20 patients previously examined with gadolinium-enhanced MRA and with digital subtraction angiography (DSA) for abdominal aortic aneurysm were retrospectively evaluated by three independent readers. The MRA datasets were viewed using VRT with three different standardized transfer functions: the percentile method (Pc-VRT), the maximum-likelihood method (ML-VRT), and the partial range histogram method (PRH-VRT). The aortic diameters obtained with these three methods were compared with freely chosen VRT parameters (F-VRT) and with maximum intensity projection (MIP) concerning inter-reader variability and agreement with the reference method DSA. F-VRT parameters and PRH-VRT gave significantly higher diameter values than DSA, whereas Pc-VRT gave significantly lower values than DSA. The highest interobserver variability was found for F-VRT parameters and MIP, and the lowest for Pc-VRT and PRH-VRT. All standardized VRT methods were significantly superior to both MIP and F-VRT in this respect. The agreement with DSA was best for PRH-VRT, which was the only method with a mean error below 1 mm and which also had the narrowest limits of agreement (95% of cases between 2.1 mm below and 3.1 mm above DSA). All the standardized VRT methods compare favorably with MIP and VRT with freely selected parameters as regards interobserver variability. The partial range histogram method, although systematically overestimating vessel diameters, gives results closest to those of DSA.
Radiofrequency Ablation Using a Multiple-Electrode Switching System for Lung Tumors with 2.0-5.0-cm Maximum Diameter: Phase II Clinical Study.

PubMed

Kodama, Hiroshi; Yamakado, Koichiro; Hasegawa, Takaaki; Fujimori, Masashi; Yamanaka, Takashi; Takaki, Haruyuki; Uraki, Junji; Nakatsuka, Atsuhiro; Sakuma, Hajime

2015-12-01

To prospectively evaluate the safety and effectiveness of radiofrequency ablation (RFA) by using a multiple-electrode switching system to treat 2.0-5.0-cm lung tumors. The institutional review board approved this prospective phase II study. Written informed consent was obtained from all patients. Between September 2009 and July 2011, RFA using two or three radiofrequency (RF) electrodes and a multiple-electrode switching system was performed for malignant lung tumors with a maximum tumor diameter of 2.0-5.0 cm in nonsurgical candidates. The primary endpoint was safety, as evaluated using the Common Terminology Criteria for Adverse Events. Patients were observed for at least 1 year. Local tumor progression and overall survival were analyzed with the Kaplan-Meier method. Thirty-three patients (26 men, seven women; mean age, 70.5 years ± 10.0; age range, 46-87 years) with 35 lung tumors with a mean maximum diameter of 3.0 cm ± 0.7 (standard deviation; range, 2.0-4.4 cm) underwent treatment in 35 sessions. No procedure-related death or grade 4 adverse events (AEs) occurred. Grade 3 AEs occurred in four patients (12%), with pleural effusion requiring chest tube placement in two patients, pneumothorax requiring pleural adhesion in one patient, and pulmonary hemorrhage requiring pulmonary artery coil embolization in one patient. Grade 2 AEs were detected in 13 patients (39%). The 1-year local tumor progression and overall survival rates were 12.7% (95% confidence interval [CI]: 1.0, 25.5) and 81.2% (95% CI: 67.6, 94.8). RFA with a multiple-electrode switching system may be a safe therapeutic option with which to treat 2.0-5.0-cm lung cancer tumors.
Stone Attenuation Values Measured by Average Hounsfield Units and Stone Volume as Predictors of Total Laser Energy Required During Ureteroscopic Lithotripsy Using Holmium:Yttrium-Aluminum-Garnet Lasers.

PubMed

Ofude, Mitsuo; Shima, Takashi; Yotsuyanagi, Satoshi; Ikeda, Daisuke

2017-04-01

To evaluate the predictors of the total laser energy (TLE) required during ureteroscopic lithotripsy (URS) using the holmium:yttrium-aluminum-garnet (Ho:YAG) laser for a single ureteral stone. We retrospectively analyzed the data of 93 URS procedures performed for a single ureteral stone in our institution from November 2011 to September 2015. We evaluated the association between TLE and preoperative clinical data, such as age, sex, body mass index, and noncontrast computed tomographic findings, including stone laterality, location, maximum diameter, volume, stone attenuation values measured using average Hounsfield units (HUs), and presence of secondary signs (severe hydronephrosis, tissue rim sign, and perinephric stranding). The mean maximum stone diameter, volume, and average HUs were 9.2 ± 3.8 mm, 283.2 ± 341.4 mm 3 , and 863 ± 297, respectively. The mean TLE and operative time were 2.93 ± 3.27 kJ and 59.1 ± 28.1 minutes, respectively. Maximum stone diameter, volume, average HUs, severe hydronephrosis, and tissue rim sign were significantly correlated with TLE (Spearman's rho analysis). Stepwise multiple linear regression analysis defining stone volume, average HUs, severe hydronephrosis, and tissue rim sign as explanatory variables showed that stone volume and average HUs were significant predictors of TLE (standardized coefficients of 0.565 and 0.320, respectively; adjusted R 2 = 0.55, F = 54.7, P <.001). Stone attenuation values measured by average HUs and stone volume were strong predictors of TLE during URS using Ho:YAG laser procedures. Copyright © 2016 Elsevier Inc. All rights reserved.
Proposal for a New Prognostic Score for Linac-Based Radiosurgery in Cerebral Arteriovenous Malformations

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

Milker-Zabel, Stefanie, E-mail: Stefanie_Milker-Zabel@med.uni-heidelberg.de; Kopp-Schneider, Annette; Wiesbauer, Hannah

2012-06-01

Purpose: We evaluate patient-, angioma-, and treatment-specific factors for successful obliteration of cerebral arteriovenous malformations (AVM) to develop a new appropriate score to predict patient outcome after linac-based radiosurgery (RS). Methods and Materials: This analysis in based on 293 patients with cerebral AVM. Mean age at treatment was 38.8 years (4-73 years). AVM classification according Spetzler-Martin was 55 patients Grade I (20.5%), 114 Grade II (42.5%), 79 Grade III (29.5%), 19 Grade IV (7.1%), and 1 Grade V (0.4%). Median maximum AVM diameter was 3.0 cm (range, 0.3-10 cm). Median dose prescribed to the 80% isodose was 18 Gy (range,more » 12-22 Gy). Eighty-five patients (29.1%) had prior partial embolization; 141 patients (51.9%) experienced intracranial hemorrhage before RS. Median follow-up was 4.2 years. Results: Age at treatment, maximum diameter, nidus volume, and applied dose were significant factors for successful obliteration. Under presumption of proportional hazard in the dose range between 12 and 22 Gy/80% isodose, an increase of obliteration rate of approximately 25% per Gy was seen. On the basis of multivariate analysis, a prediction score was calculated including AVM maximum diameter and age at treatment. The prediction error up to the time point 8 years was 0.173 for the Heidelberg score compared with the Kaplan-Meier value of 0.192. An increase of the score of 1 point results in a decrease of obliteration chance by a factor of 0.447. Conclusion: The proposed score is linac-based radiosurgery-specific and easy to handle to predict patient outcome. Further validation on an independent patient cohort is necessary.« less
Synthesis of copper nanocolloids using a continuous flow based microreactor

NASA Astrophysics Data System (ADS)

Xu, Lei; Peng, Jinhui; Srinivasakannan, C.; Chen, Guo; Shen, Amy Q.

2015-11-01

The copper (Cu) nanocolloids were prepared by sodium borohydride (NaBH4) reduction of metal salt solutions in a T-shaped microreactor at room temperature. The influence of NaBH4 molar concentrations on copper particle's diameter, morphology, size distribution, and elemental compositions has been investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The ultraviolet-visible spectroscopy (UV-vis) was used to verify the chemical compounds of nanocolloids and estimate the average size of copper nanocolloids. The synthesized copper nanocolloids were uniform in size and non-oxidized. A decrease in the mean diameter of copper nanocolloids was observed with increasing NaBH4 molar concentrations. The maximum mean diameter (4.25 nm) occurred at the CuSO4/NaBH4 molar concentration ratio of 1:2.
BROACHING AND TUBE-INSTALLING APPARATUS

DOEpatents

Frantz, C.E.; Cawley, W.E.

1961-05-16

An apparatus is given for sizing long holes in graphite bodies. The apparatus comprises a shaft having 3 spiral broach cutting elements and a straight broach cutting element rotatably mounted thereon. The broach cutting elements are keyed to each other in end to end relationship with the straight broach cutting element at one end of the shaft. The spiral broach cutting elements when considered toward the straight broach cutting element increase in diameter and the cutting teeth thereon increase in lead angle. The straight broach cutting element, when considered in the same direction, increases in diameter from the minimum to maximum diameters of the spiral broach cutting elements. No longitudinal movement of the broach cutting elements is permitted on the shsft snd means are provided for the removal of chips from the apparatus.
Status, technology and development of silicon solar cells at INER

NASA Astrophysics Data System (ADS)

Jao, S. S.; Tseng, H. H.; Cheng, C.; Tzeng, Y. C.; Chang, H. H.; Hwang, H. L.

Test runs using 200 5-cm-diameter silicon wafers are carried out, yielding 87% with an AM1 conversion efficiency greater than 11.5%. The highest efficiency is 12.7%. Concentrator solar cells of 2 x 2 sq cm are made with an AM1 efficiency of 14%. Solar cells with a diameter of 7.5 cm have attained AM1 efficiencies of more than 11.3%, and texturized solar cells of the same diameter fabricated from rejected wafers show AM1 efficiencies of 9.5-10.5%. It is noted that solar panels comprising 68 cells with a maximum output power of 13.5 W have been manufactured. The results of a 6-month test of a photovoltaic charge station for electric motorcycles are reported.
Transsacral Osseous Corridor Anatomy Is More Amenable To Screw Insertion In Males: A Biomorphometric Analysis of 280 Pelves.

PubMed

Gras, Florian; Gottschling, Heiko; Schröder, Manuel; Marintschev, Ivan; Hofmann, Gunther O; Burgkart, Rainer

2016-10-01

Percutaneous iliosacral screw placement is the standard procedure for fixation of posterior pelvic ring lesions, although a transsacral screw path is being used more frequently in recent years owing to increased fracture-fixation strength and better ability to fix central and bilateral sacral fractures. However, biomorphometric data for the osseous corridors are limited. Because placement of these screws in a safe and effective manner is crucial to using transsacral screws, we sought to address precise sacral anatomy in more detail to look for anatomic variation in the general population. We asked: (1) What proportion of healthy pelvis specimens have no transsacral corridor at the level of the S1 vertebra owing to sacral dysmorphism? (2) If there is no safe diameter for screw placement in the transsacral S1 corridor, is an increased and thus safe diameter of the transsacral S2 corridor expected? (3) Are there sex-specific differences in sacral anatomy and are these correlated with known anthropometric parameters? CT scans of pelves of 280 healthy patients acquired exclusively for medical indications such as polytrauma (20%), CT angiography (70%), and other reasons (10%), were segmented manually. Using an advanced CT-based image analysis system, the mean shape of all segmented pelves was generated and functioned as a template. On this template, the cylindric transsacral osseous corridor at the level of the S1 and S2 vertebrae was determined manually. Each pelvis then was registered to the template using a free-form registration algorithm to measure the maximum screw corridor diameters on each specimen semiautomatically. Thirty of 280 pelves (11%) had no transsacral S1 corridor owing to sacral dysmorphism. The average of maximum cylindrical diameters of the S1 corridor for the remaining 250 pelves was 12.8 mm (95% CI, 12.1-13.5 mm). A transverse corridor for S2 was found in 279 of 280 pelves, with an average of maximum cylindrical diameter of 11.6 mm (95% CI, 11.3-11.9 mm). Decreasing transsacral S1 corridor diameters are correlated with increasing transsacral S2 corridor diameters (R value for females, -0.260, p < 0.01; for males, -0.311, p < 0.001). Female specimens were more likely to have sacral dysmorphism (defined as a pelvis without a transsacral osseous corridor at the level of the S1 vertebra) than were male specimens (females, 16%; males, 7%; p < 0.003). Furthermore female pelves had smaller-corridor diameters than did male pelves (females versus males for S1: 11.7 mm [95% CI, 10.6-12.8 mm] versus 13.5 mm [95% CI, 12.6-14.4 mm], p < 0.01; and for S2: 10.6 mm [95% CI, 10.1-11.1 mm] versus 12.2 mm [95% CI, 11.8-12.6 mm ], p < 0.0001). Narrow corridors and highly individual, sex-dependent variance of morphologic features of the sacrum make transsacral implant placement technically demanding. Individual preoperative axial-slice CT scan analyses and orthogonal coronal and sagittal reformations are recommended to determine the prevalence of sufficient-sized osseous corridors on both levels for safe screw placements, especially in female patients, owing to their smaller corridor diameters and higher rate of sacral dysmorphism.
Exploring the Morphology of oceanic ridges with experiments using colloidal dispersions

NASA Astrophysics Data System (ADS)

Davaille, Anne; Sibrant, Aurore; Mittelstaedt, Eric; Aubertin, Alban; Auffray, Lionel; Pidoux, Raphael

2017-04-01

Mid-ocean ridges exhibit significant changes in their structural, morphological, and volcanic characteristics with changes in lithospheric thickness and/or spreading velocity. However, to separate the respective roles of those two partly correlated effects is difficult with only field data. We therefore designed a series of laboratory experiments using colloidal silica dispersions as an Earth analogue. Saline water solutions placed in contact with these fluids, cause formation of a skin through salt diffusion, whose rheology evolves from purely viscous to elastic and brittle with increasing salinity. Applying a fixed spreading rate to this pre- formed, brittle plate results in cracks, faults and axial ridge structures. Lithospheric (skin) thickness at a given extension rate can be varied by changing the surface water layer salinity. Moreover, the mechanical properties of the skin can also be independently controlled by changing the type of colloid. We focus here on cases where the spreading direction is perpendicular to the ridge axis. For a given dispersion and salinity, we observe four regimes as the spreading rate increases: (1) at the slowest spreading rates, the spreading axis is composed of several segments separated by non-transform offsets and has a fault-bounded, deep, U-shaped axial valley. The axis has a large sinuosity, rough topography, and jumps repeatedly. (2) At intermediate spreading rates, the spreading axis shows low sinuosity, overlapping spreading centers (OSC) , a smooth axial morphology, and very few to no jumps. The axial valley is shallow and shows a V-shape morphology. The OSCs have a ratio of length to width of 3 to 1. (3) At faster spreading rates, the axis is continuous and presents an axial high topography. (4) At the fastest spreading rates tested, the spreading axis is again segmented. Each segment is offset by well developed transform faults and the axis has a sinuosity comparable to those of regimes 2 and 3. Rotating and growing microplates are also observed in regimes 3 and 4. These four regimes, as well as the decrease in sinuosity with increasing spreading rate (regime 1) down to a critical value (regimes 2 to 4), present strong similarities with natural cases. This is predicted by a new dimensionless number ΠF comparing the maximum fracture length attainable without plasticity to the axial thickness. Slow spreading, fault-dominated ridges and fast spreading, dike-dominated ridges on Earth and in the laboratory are separated by the same critical ΠF value. Moreover, our results suggests that the fraction M of spreading rate accomodated by magmatic dyke opening is closely related to ΠF.
3D thermal model of laser surface glazing for H13 tool steel

NASA Astrophysics Data System (ADS)

Kabir, I. R.; Yin, D.; Naher, S.

2017-10-01

In this work a three dimensional (3D) finite element model of laser surface glazing (LSG) process has been developed. The purpose of the 3D thermal model of LSG was to achieve maximum accuracy towards the predicted outcome for optimizing the process. A cylindrical geometry of 10mm diameter and 1mm length was used in ANSYS 15 software. Temperature distribution, depth of modified zone and cooling rates were analysed from the thermal model. Parametric study was carried out varying the laser power from 200W-300W with constant beam diameter and residence time which were 0.2mm and 0.15ms respectively. The maximum surface temperature 2554°K was obtained for power 300W and minimum surface temperature 1668°K for power 200W. Heating and cooling rates increased with increasing laser power. The depth of the laser modified zone attained for 300W power was 37.5µm and for 200W power was 30µm. No molten zone was observed at 200W power. Maximum surface temperatures obtained from 3D model increased 4% than 2D model presented in author's previous work. In order to verify simulation results an analytical solution of temperature distribution for laser surface modification was used. The surface temperature after heating was calculated for similar laser parameters which is 1689°K. The difference in maximum surface temperature is around 20.7°K between analytical and numerical analysis of LSG for power 200W.
Optimal strategy for controlling the spread of Plasmodium Knowlesi malaria: Treatment and culling

NASA Astrophysics Data System (ADS)

Abdullahi, Mohammed Baba; Hasan, Yahya Abu; Abdullah, Farah Aini

2015-05-01

Plasmodium Knowlesi malaria is a parasitic mosquito-borne disease caused by a eukaryotic protist of genus Plasmodium Knowlesi transmitted by mosquito, Anopheles leucosphyrus to human and macaques. We developed and analyzed a deterministic Mathematical model for the transmission of Plasmodium Knowlesi malaria in human and macaques. The optimal control theory is applied to investigate optimal strategies for controlling the spread of Plasmodium Knowlesi malaria using treatment and culling as control strategies. The conditions for optimal control of the Plasmodium Knowlesi malaria are derived using Pontryagin's Maximum Principle. Finally, numerical simulations suggested that the combination of the control strategies is the best way to control the disease in any community.
Experimental comparison of various techniques for spot size measurement of high-energy X-ray

NASA Astrophysics Data System (ADS)

Wang, Yi; Li, Qin; Chen, Nan; Cheng, Jin-Ming; Li, Cheng-Gang; Li, Hong; Long, Quan-Hong; Shi, Jin-Shui; Deng, Jian-Jun

2016-08-01

In flash-radiography experiments, the quality of the acquired image strongly depends on the focal size of the X-ray source spot. A variety of techniques based on imaging of the pinhole, the slit and the rollbar are adopted to measure the focal spot size of the Dragon-I linear induction accelerator. The image of the pinhole provides a two-dimensional distribution of the X-ray spot, while those of the slit and the rollbar give a line-spread distribution and an edge-spread distribution, respectively. The spot size characterized by the full-width at half-maximum and that characterized by the LANL definition are calculated for comparison.
Performance Analysis of HF Band FB-MC-SS

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

Hussein Moradi; Stephen Andrew Laraway; Behrouz Farhang-Boroujeny

Abstract—In a recent paper [1] the filter bank multicarrier spread spectrum (FB-MC-SS) waveform was proposed for wideband spread spectrum HF communications. A significant benefit of this waveform is robustness against narrow and partial band interference. Simulation results in [1] demonstrated good performance in a wideband HF channel over a wide range of conditions. In this paper we present a theoretical analysis of the bit error probably for this system. Our analysis tailors the results from [2] where BER performance was analyzed for maximum ration combining systems that accounted for correlation between subcarriers and channel estimation error. Equations are give formore » BER that closely match the simulated performance in most situations.« less
Distributing value gain from three growth factors for yellow-poplar

Treesearch

Roger E. McCay

1969-01-01

A method of apportioning the maximum dollar value gain from tree growth into the amounts contributed by diameter growth, merchantable height increase, and quality improvement is described. The results of this method are presented for various sizes and qualities of yellow-poplar trees.
7 CFR 51.2836 - Size classifications.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Size classifications. 51.2836 Section 51.2836...) Size Classifications § 51.2836 Size classifications. The size of onions may be specified in accordance with one of the following classifications. Size designation Minimum diameter Inches Millimeters Maximum...
7 CFR 51.2836 - Size classifications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Size classifications. 51.2836 Section 51.2836...) Size Classifications § 51.2836 Size classifications. The size of onions may be specified in accordance with one of the following classifications. Size designation Minimum diameter Inches Millimeters Maximum...
7 CFR 51.2836 - Size classifications.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Size classifications. 51.2836 Section 51.2836...) Size Classifications § 51.2836 Size classifications. The size of onions may be specified in accordance with one of the following classifications. Size designation Minimum diameter Inches Millimeters Maximum...

A novel electron accelerator for MRI-Linac radiotherapy.

PubMed

Whelan, Brendan; Gierman, Stephen; Holloway, Lois; Schmerge, John; Keall, Paul; Fahrig, Rebecca

2016-03-01

MRI guided radiotherapy is a rapidly growing field; however, current electron accelerators are not designed to operate in the magnetic fringe fields of MRI scanners. As such, current MRI-Linac systems require magnetic shielding, which can degrade MR image quality and limit system flexibility. The purpose of this work was to develop and test a novel medical electron accelerator concept which is inherently robust to operation within magnetic fields for in-line MRI-Linac systems. Computational simulations were utilized to model the accelerator, including the thermionic emission process, the electromagnetic fields within the accelerating structure, and resulting particle trajectories through these fields. The spatial and energy characteristics of the electron beam were quantified at the accelerator target and compared to published data for conventional accelerators. The model was then coupled to the fields from a simulated 1 T superconducting magnet and solved for cathode to isocenter distances between 1.0 and 2.4 m; the impact on the electron beam was quantified. For the zero field solution, the average current at the target was 146.3 mA, with a median energy of 5.8 MeV (interquartile spread of 0.1 MeV), and a spot size diameter of 1.5 mm full-width-tenth-maximum. Such an electron beam is suitable for therapy, comparing favorably to published data for conventional systems. The simulated accelerator showed increased robustness to operation in in-line magnetic fields, with a maximum current loss of 3% compared to 85% for a conventional system in the same magnetic fields. Computational simulations suggest that replacing conventional DC electron sources with a RF based source could be used to develop medical electron accelerators which are robust to operation in in-line magnetic fields. This would enable the development of MRI-Linac systems with no magnetic shielding around the Linac and reduce the requirements for optimization of magnetic fringe field, simplify design of the high-field magnet, and increase system flexibility.
A novel electron accelerator for MRI-Linac radiotherapy

PubMed Central

Whelan, Brendan; Gierman, Stephen; Holloway, Lois; Schmerge, John; Keall, Paul; Fahrig, Rebecca

2016-01-01

Purpose: MRI guided radiotherapy is a rapidly growing field; however, current electron accelerators are not designed to operate in the magnetic fringe fields of MRI scanners. As such, current MRI-Linac systems require magnetic shielding, which can degrade MR image quality and limit system flexibility. The purpose of this work was to develop and test a novel medical electron accelerator concept which is inherently robust to operation within magnetic fields for in-line MRI-Linac systems. Methods: Computational simulations were utilized to model the accelerator, including the thermionic emission process, the electromagnetic fields within the accelerating structure, and resulting particle trajectories through these fields. The spatial and energy characteristics of the electron beam were quantified at the accelerator target and compared to published data for conventional accelerators. The model was then coupled to the fields from a simulated 1 T superconducting magnet and solved for cathode to isocenter distances between 1.0 and 2.4 m; the impact on the electron beam was quantified. Results: For the zero field solution, the average current at the target was 146.3 mA, with a median energy of 5.8 MeV (interquartile spread of 0.1 MeV), and a spot size diameter of 1.5 mm full-width-tenth-maximum. Such an electron beam is suitable for therapy, comparing favorably to published data for conventional systems. The simulated accelerator showed increased robustness to operation in in-line magnetic fields, with a maximum current loss of 3% compared to 85% for a conventional system in the same magnetic fields. Conclusions: Computational simulations suggest that replacing conventional DC electron sources with a RF based source could be used to develop medical electron accelerators which are robust to operation in in-line magnetic fields. This would enable the development of MRI-Linac systems with no magnetic shielding around the Linac and reduce the requirements for optimization of magnetic fringe field, simplify design of the high-field magnet, and increase system flexibility. PMID:26936713
Single-drop impingement onto a wavy liquid film and description of the asymmetrical cavity dynamics

NASA Astrophysics Data System (ADS)

van Hinsberg, Nils Paul; Charbonneau-Grandmaison, Marie

2015-07-01

The present paper is devoted to an experimental investigation of the cavity formed upon a single-drop impingement onto a traveling solitary surface wave on a deep pool of the same liquid. The dynamics of the cavity throughout its complete expansion and receding phase are analyzed using high-speed shadowgraphy and compared to the outcomes of drop impingements onto steady liquid surface films having equal thickness. The effects of the surface wave velocity, amplitude and phase, drop impingement velocity, and liquid viscosity on the cavity's diameter and depth evolution are accurately characterized at various time instants. The wave velocity induces a distinct and in time increasing inclination of the cavity in the wave propagation direction. In particular for strong waves an asymmetrical distribution of the radial expansion and retraction velocity along the cavity's circumference is observed. A linear dependency between the absolute Weber number and the typical length and time scales associated with the cavity's maximum depth and maximum diameter is reported.
Fabrication and characteristics of thin disc piezoelectric transformers based on piezoelectric buzzers with gap circles.

PubMed

Chang, Kuo-Tsai; Lee, Chun-Wei

2008-04-01

This paper investigates design, fabrication and test of thin disc piezoelectric transformers (PTs) based on piezoelectric buzzers with gap circles at different diameters of the gap circles. The performance test is focused on characteristics of voltage gains, including maximum voltage gains and maximum-gain frequencies, for each piezoelectric transformer under different load conditions. Both a piezoelectric buzzer and a gap circle on a silver electrode of the buzzer are needed to build any type of the PTs. Here, the gap circle is used to form a ring-shaped input electrode and a circle-shaped output electrode for each piezoelectric transformer. To do so, both structure and connection of a PT are first expressed. Then, operating principle of a PT and its related vibration mode observed by a carbon-power imaging technique are described. Moreover, an experimental setup for characterizing each piezoelectric transformer is constructed. Finally, effects of diameters of the gap circles on characteristics of voltage gains at different load resistances are discussed.
Large area Czochralski silicon

NASA Technical Reports Server (NTRS)

Rea, S. N.; Gleim, P. S.

1977-01-01

The overall cost effectiveness of the Czochralski process for producing large-area silicon was determined. The feasibility of growing several 12 cm diameter crystals sequentially at 12 cm/h during a furnace run and the subsequent slicing of the ingot using a multiblade slurry saw were investigated. The goal of the wafering process was a slice thickness of 0.25 mm with minimal kerf. A slice + kerf of 0.56 mm was achieved on 12 cm crystal using both 400 grit B4C and SiC abrasive slurries. Crystal growth experiments were performed at 12 cm diameter in a commercially available puller with both 10 and 12 kg melts. Several modifications to the puller hoz zone were required to achieve stable crystal growth over the entire crystal length and to prevent crystallinity loss a few centimeters down the crystal. The maximum practical growth rate for 12 cm crystal in this puller design was 10 cm/h, with 12 to 14 cm/h being the absolute maximum range at which melt freeze occurred.
Experimental analysis of robot-assisted needle insertion into porcine liver.

PubMed

Wang, Wendong; Shi, Yikai; Goldenberg, Andrew A; Yuan, Xiaoqing; Zhang, Peng; He, Lijing; Zou, Yingjie

2015-01-01

How to improve placement accuracy of needle insertion into liver tissue is of paramount interest to physicians. A robot-assisted system was developed to experimentally demonstrate its advantages in needle insertion surgeries. Experiments of needle insertion into porcine liver tissue were performed with conic tip needle (diameter 8 mm) and bevel tip needle (diameter 1.5 mm) in this study. Manual operation was designed to compare the performance of the presented robot-assisted system. The real-time force curves show outstanding advantages of robot-assisted operation in improving the controllability and stability of needle insertion process by comparing manual operation. The statistics of maximum force and average force further demonstrates robot-assisted operation causes less oscillation. The difference of liver deformation created by manual operation and robot-assisted operation is very low, 1 mm for average deformation and 2 mm for maximum deformation. To conclude, the presented robot-assisted system can improve placement accuracy of needle by stably control insertion process.
On the residual stress modeling of shot-peened AISI 4340 steel: finite element and response surface methods

NASA Astrophysics Data System (ADS)

Asgari, Ali; Dehestani, Pouya; Poruraminaie, Iman

2018-02-01

Shot peening is a well-known process in applying the residual stress on the surface of industrial parts. The induced residual stress improves fatigue life. In this study, the effects of shot peening parameters such as shot diameter, shot speed, friction coefficient, and the number of impacts on the applied residual stress will be evaluated. To assess these parameters effect, firstly the shot peening process has been simulated by finite element method. Then, effects of the process parameters on the residual stress have been evaluated by response surface method as a statistical approach. Finally, a strong model is presented to predict the maximum residual stress induced by shot peening process in AISI 4340 steel. Also, the optimum parameters for the maximum residual stress are achieved. The results indicate that effect of shot diameter on the induced residual stress is increased by increasing the shot speed. Also, enhancing the friction coefficient magnitude always cannot lead to increase in the residual stress.
Optimization of elutriation device for filtration of microplastic particles from sediment.

PubMed

Zhu, X

2015-03-15

The increasing presence of plastic pollution in marine ecosystems has become a major concern. In the environment, plastics break down into smaller and smaller pieces of microplastics. Methods of microplastic recovery are needed to reduce the dangers they can pose to a variety of organisms. An elutriation device was manufactured and optimized to achieve maximum microplastic recovery. The parameters flow rate and diameter of elutriation column were varied and their domain of variation was determined. A composite factorial experimental design was generated using MODDE 10.1 and was undergone. The optimal values of flow rate and column diameter were determined to be 385 L h(-1) and 5.06 cm respectively, under constraints, to achieve a maximum feasible microplastics recovery percentage of 50.2%. The elutriation process can be improved through further testing, and can be tested in the field to compare its efficiency to that of manual microplastics filtration. Copyright © 2015 Elsevier Ltd. All rights reserved.
2, 4, 6-Trithiol-1, 3, 5-Triazine-Modified Gold Nanoparticles and Its Potential as Formalin Detector

NASA Astrophysics Data System (ADS)

Yulizar, Y.; Ariyanta, H. A.; Rakhmania, L.; Hafizah, M. A. E.

2018-04-01

Stabilized gold nanoparticles (AuNP) have been successfully prepared by a modification of ligand 2, 4, 6-trithiol-1, 3, 5-triazine (TT). TT has three thiol groups and nitrogen atoms on the aromatic ring that can interact and stabilize AuNP. TT modified AuNP (AuNP/TT) was characterized using UV-Vis spectrophotometer, particle size analyzer (PSA) and transmission electron microscopy (TEM). The characterization showed that AuNP/TT stable at a maximum wavelength (λmaks) of 537 nm with the particle diameter of 9.41 nm. The increased acidity (pH) causes the protonated thiol groups of TT marked with a visual change of colloidal AuNP/TT from purple to blue, causing AuNP and TT bonds weakened. In this study, the AuNP/TT was reacted with formalin. This interaction shows that AuNP/TT has a potential as an efficient detector of formalin, marked by changes in the diameter of the particle, colloidal color, and maximum wavelength shift.
A Tissue-Mimicking Ultrasound Test Object Using Droplet Vaporization to Create Point Targets

PubMed Central

Carneal, Catherine M.; Kripfgans, Oliver D.; Krücker, Jochen; Carson, Paul L.; Fowlkes, J. Brian

2012-01-01

Ultrasound test objects containing reference point targets could be useful for evaluating ultrasound systems and phase aberration correction methods. Polyacrylamide gels containing albumin-stabilized droplets (3.6 µm mean diameter) of dodecafluoropentane (DDFP) are being developed for this purpose. Perturbation by ultrasound causes spontaneous vaporization of the superheated droplets to form gas bubbles, a process termed acoustic droplet vaporization (ADV). The resulting bubbles (20 to 160 µm diameter) are small compared with acoustic wavelengths in diagnostic ultrasound and are theoretically suitable for use as point targets (phase errors <20° for typical f-numbers). Bubbles distributed throughout the material are convenient for determining the point spread function in an imaging plane or volume. Cooling the gel causes condensation of the DDFP droplets, which may be useful for storage. Studying ADV in such viscoelastic media could provide insight into potential bioeffects from rapid bubble formation. PMID:21937339
Narrowly peaked forward light scattering on particulate media: II. Angular spreading of light scattered by polystyrene microspheres

NASA Astrophysics Data System (ADS)

Turcu, Ioan; Bratfalean, Radu; Neamtu, Silvia

2008-07-01

The adequacy of the effective phase function (EPF) used to describe the light scattered at small angles was tested on aqueous suspensions of polystyrene microspheres. Angular resolved light scattering measurements were performed on two types of latex suspension, which contained polystyrene spheres of 3 µm and 5 µm diameters, respectively. The experimental data were fitted with two EPF approximants. If the polystyrene spheres are at least 3 µm in diameter the quasi-ballistic light scattering process can be described relatively well by the EPF in a small angular range centered in the forward direction. The forward light scattering by macroscopic samples containing microspheres can be modeled relatively well if the true Mie single particle scattering phase function is replaced by a simpler Henyey-Greenstein dependence having the same width at half-height as the first scattering lobe.
Malignant melanoma with preserved hairs: a snap shot could suggest the development from an acquired melanocytic nevus.

PubMed

Kiyohara, Takahiro; Kouraba, Sachio; Takahashi, Hidenori; Kawasaki, Takeo; Takeuchi, Akiteru; Kumakiri, Masanobu

2010-02-01

63-year-old man presented with a dome-shaped, black nodule on his right forehead, where hairs were preserved. The black surface tone measured 7 mm in diameter and spread irregularly from the periphery of the nodule. He had been conscious of the preceding, black macule for approximately 50 years. A snap shot of the patient in adolescence showed a tiny, black macule, which was a few millimeters in diameter. Histological examination demonstrated irregular proliferation of melanoma cells from the epidermis to the dermis. Partially, there were well-circumscribed, oval nests composed of nevus cells in the acanthotic epidermis and follicles. Nevus cells were also seen in the dermal component, presenting a burnt-out appearance. In this case, the small final size, the preserved hairs and the snap shot suggested a preceding, acquired melanocytic nevus. Malignant melanoma could arise from acquired melanocytic nevus.
Strawberry Accessions with Reduced Drosophila suzukii Emergence From Fruits

PubMed Central

Gong, Xiaoyun; Bräcker, Lasse; Bölke, Nadine; Plata, Camila; Zeitlmayr, Sarah; Metzler, Dirk; Olbricht, Klaus; Gompel, Nicolas; Parniske, Martin

2016-01-01

Drosophila suzukii is threatening soft fruit production worldwide due to the females’ ability to pierce through the intact skin of ripe fruits and lay eggs inside. Larval consumption and the associated microbial infection cause rapid fruit degradation, thus drastic yield and economic loss. Cultivars that limit the proliferation of flies may be ideal to counter this pest; however, they have not yet been developed or identified. To search for potential breeding material, we investigated the rate of adult D. suzukii emergence from individual fruits (fly emergence) of 107 accessions of Fragaria species that had been exposed to egg-laying D. suzukii females. We found significant variation in fly emergence across strawberries, which correlated with accession and fruit diameter, and to a lesser extent with the strawberry species background. We identified accessions with significantly reduced fly emergence, not explained by their fruit diameter. These accessions constitute valuable breeding material for strawberry cultivars that limit D. suzukii spread. PMID:28066452
Single-bubble dynamics in pool boiling of one-component fluids

NASA Astrophysics Data System (ADS)

Xu, Xinpeng; Qian, Tiezheng

2014-06-01

We numerically investigate the pool boiling of one-component fluids with a focus on the effects of surface wettability on the single-bubble dynamics. We employed the dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007), 10.1103/PhysRevE.75.036304], a diffuse-interface model for liquid-vapor flows involving liquid-vapor transition in nonuniform temperature fields. We first perform simulations for bubbles on homogeneous surfaces. We find that an increase in either the contact angle or the surface superheating can enhance the bubble spreading over the heating surface and increase the bubble departure diameter as well and therefore facilitate the transition into film boiling. We then examine the dynamics of bubbles on patterned surfaces, which incorporate the advantages of both hydrophobic and hydrophilic surfaces. The central hydrophobic region increases the thermodynamic probability of bubble nucleation while the surrounding hydrophilic region hinders the continuous bubble spreading by pinning the contact line at the hydrophobic-hydrophilic intersection. This leads to a small bubble departure diameter and therefore prevents the transition from nucleate boiling into film boiling. With the bubble nucleation probability increased and the bubble departure facilitated, the efficiency of heat transfer on such patterned surfaces is highly enhanced, as observed experimentally [Int. J. Heat Mass Transfer 57, 733 (2013), 10.1016/j.ijheatmasstransfer.2012.10.080]. In addition, the stick-slip motion of contact line on patterned surfaces is demonstrated in one-component fluids, with the effect weakened by surface superheating.
SU-F-J-63: Abdominal Diameter Changes in Children During Volumetric Modulated Arc Therapy (VMAT): Is Re-Planning Needed?

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

Guerreiro, F; Janssens, G; Seravalli, E

Purpose: To investigate the dosimetric impact of daily changes in patient’s diameter, due to weight gain/loss and air in the bowel, based on CBCT information during radiotherapy treatment of pediatric abdominal tumors. Methods: 10 pediatric patients with neuroblastoma (n=6) and Wilms’ (n=4) tumors were included. Available CBCTs were affinely registered to the planning CT for daily set-up variations corrections. A density override approach assigning air-density to the random air pockets and water-density to the remaining anatomy was used to determine the CBCT and CT dose. Clinical VMAT plans, with a PTV prescribed dose ranging between (14.4- 36) Gy, were re-optimizedmore » on the density override CT and re-calculated on each CBCT. Dose-volume statistics of the PTV and kidneys, delineated on each CBCT, were used to compare the daily and cumulative CBCT dose with the reference CT dose. Results: The average patient diameter variation was (0.5 ± 0.7) cm (maximum daily difference of 2.3 cm). The average PTV mean dose difference (MDD) between the CT and the cumulative CBCT plans was (0.1 ± 1.1) % (maximum daily MDD of 2%). A reduction in target coverage up to 3% and 7% was observed for the cumulative and daily CBCT plans, respectively. The average kidneys’ cumulative MDD was (−2.7 ± 3.6) % (maximum daily MDD of −12%), corresponding to an overdosage. Conclusion: Due to patient’s diameter changes, a target underdosage was assessed. Given the high local tumor control of neuroblastoma and Wilms’ diseases, the need of re-planning might be discarded. However, the assessed kidneys overdosage could represent a problem when the normal tissue tolerance is reached. The necessity of re-planning should then be considered to reduce the risk of long-term renal complications. Due to the poor softtissue contrast on CBCT, MRI-guidance is required to obtain a better assessment of the accumulated dose on the remaining OARs.« less
Concentration, size distribution and dry deposition of amines in atmospheric particles of urban Guangzhou, China

NASA Astrophysics Data System (ADS)

Liu, Fengxian; Bi, Xinhui; Zhang, Guohua; Peng, Long; Lian, Xiufeng; Lu, Huiying; Fu, Yuzhen; Wang, Xinming; Peng, Ping'an; Sheng, Guoying

2017-12-01

Size-segregated PM10 samples were collected in Guangzhou, China during autumn of 2014. Nine amines, including seven aliphatic amines and two heterocyclic amines, were detected using a gas chromatography-mass spectrometer after derivatization by benzenesulfonyl chloride. The total concentration of the nine amines (Ʃamines) was 79.6-140.9 ng m-3 in PM10. The most abundant species was methylamine (MA), which had a concentration of 29.2-70.1 ng m-3. MA, dimethylamine (DMA), diethylamine (DEA) and dibutylamine (DBA) were the predominant amines in the samples and accounted for approximately 80% of Ʃamines in each size segment. Two heterocyclic amines, pyrrolidine (PYR) and morpholine (MOR), were detected in all samples and had average concentrations of 1.14 ± 0.37 and 1.89 ± 0.64 ng m-3, respectively, in particles with aerodynamic diameters < 3 μm. More than 80% of Ʃamines were found in particles with diameters <1.5 μm, indicating that amines are mainly enriched in fine particles. All amines exhibited a bimodal distribution with a fine mode at 0.49-1.5 μm and a coarse mode at 7.2-10 μm. The maximum contributions of amines to particles (0.21%) and amines-N to water-soluble organic nitrogen (WSON) (3.1%) were found at the sizes < 0.49 μm. The maximum contribution of amines-C to water-soluble organic carbon (WSOC) was 1.6% over the size range of 0.95-1.5 μm. The molar ratio of Ʃamines to ammonium ranged from 0.0068 to 0.0107 in particles with diameters <1.5 μm, and the maximum ratio occurred in the smallest particles (diameter< 0.49 μm). The average dry deposition flux and velocity of Ʃamines in PM10 were 7.9 ± 1.6 μg m-2 d-1 and 0.084 ± 0.0021 cm s-1, respectively. The results of this study provide essential information on the contribution of amines to secondary organic aerosols and dry removal mechanisms in urban areas.
How the timberline formed: altitudinal changes in stand structure and dynamics around the timberline in central Japan.

PubMed

Takahashi, Koichi; Hirosawa, Tatsuru; Morishima, Ryohei

2012-05-01

Altitudinal timberlines are thought to move upward by global warming, a crucial topic in ecology. Tall tree species (the conifer Abies mariesii and the deciduous broad-leaved Betula ermanii) dominate the sub-alpine zone between 1600 and 2500 m a.s.l., the timberline, on Mount Norikura in central Japan. Dwarf pine Pinus pumila dominates above the timberline to near the summit (3026 m a.s.l.). This study evaluated how the timberline formed on Mount Norikura by examining altitudinal changes in stand structure and dynamics around the timberline. One hundred and twenty-five plots of 10 m × 10 m were established around the timberline (2350-2600 m a.s.l.). Trunk diameter growth rate during 6 years was examined for A. mariesii, B. ermanii and P. pumila. Mortality during this period and mechanical damage scars on the trunks and branches due to strong wind and snow were examined for A. mariesii only. The density, maximum trunk height and diameter of A. mariesii in plots decreased with altitude. The maximum trunk height of B. ermanii decreased with altitude, but density and maximum trunk diameter did not decrease. In contrast, the density of P. pumila abruptly increased from around the timberline. A strong negative correlation was found between the densities of P. pumila and tall tree species, indicating their interspecific competition. Trunk diameter growth rates of A. mariesii and B. ermanii did not decrease with altitude, suggesting that these two tall tree species can grow at the timberline. The ratio of trees with mechanical damage scars increased with altitude for A. mariesii, a tendency more conspicuous for larger trees. The mortality of larger A. mariesii was also greater at higher altitude. Tall tree species may not increase their trunk height and survive around the timberline because of mechanical damage. This study suggests that the altitudinal location of the timberline is mainly affected by mechanical damage due to strong wind and snow rather than by growth limitation due to low temperature. Therefore, the timberline would not move upward even under global warming if these growth and mortality characteristics do not change for a long time.
Effects of metal- and fiber-reinforced composite root canal posts on flexural properties.

PubMed

Kim, Su-Hyeon; Oh, Tack-Oon; Kim, Ju-Young; Park, Chun-Woong; Baek, Seung-Ho; Park, Eun-Seok

2016-01-01

The aim of this study was to observe the effects of different test conditions on the flexural properties of root canal post. Metal- and fiber-reinforced composite root canal posts of various diameters were measured to determine flexural properties using a threepoint bending test at different conditions. In this study, the span length/post diameter ratio of root canal posts varied from 3.0 to 10.0. Multiple regression models for maximum load as a dependent variable were statistically significant. The models for flexural properties as dependent variables were statistically significant, but linear regression models could not be fitted to data sets. At a low span length/post diameter ratio, the flexural properties were distorted by occurrence of shear stress in short samples. It was impossible to obtain high span length/post diameter ratio with root canal posts. The addition of parameters or coefficients is necessary to appropriately represent the flexural properties of root canal posts.
Electromagnetic characteristics of eccentric figure-eight coils for transcranial magnetic stimulation: A numerical study

NASA Astrophysics Data System (ADS)

Kato, Takuya; Sekino, Masaki; Matsuzaki, Taiga; Nishikawa, Atsushi; Saitoh, Youichi; Ohsaki, Hiroyuki

2012-04-01

Repetitive transcranial magnetic stimulation (rTMS) is effective for treatment of several neurological and psychiatric diseases. We proposed an eccentric figure-eight coil, which induces strong eddy currents in the target brain tissue. In this study, numerical analyses were carried out to obtain magnetic field distribution of the eccentric figure-eight coil and eddy current in the brain. The analyses were performed with various coil design parameters, such as the outer and inner diameters and number of turns, to investigate the influence of these parameters on the coil characteristics. Increases in the inner diameter, outer diameter, and number of turns caused increases in the maximum eddy current densities. Coil inductance, working voltage, and heat generation also became higher with the increases in these design parameters. In order to develop a compact stimulator system for use at home, we need to obtain strong eddy current density, keeping the working voltage as low as possible. Our results show that it is effective to enlarge the outer diameter.
Diameter dependent thermoelectric properties of individual SnTe nanowires

DOE PAGES

Xu, E. Z.; Li, Z.; Martinez, J. A.; ...

2015-01-15

The lead-free compound tin telluride (SnTe) has recently been suggested to be a promising thermoelectric material. In this work, we report on the first thermoelectric study of individual single-crystalline SnTe nanowires with different diameters ranging from ~ 218 to ~ 913 nm. Measurements of thermopower S, electrical conductivity σ and thermal conductivity κ were carried out on the same nanowires over a temperature range of 25 - 300 K. While the electrical conductivity does not show a strong diameter dependence, the thermopower increases by a factor of two when the nanowire diameter is decreased from ~ 913 nm to ~more » 218 nm. The thermal conductivity of the measured NWs is lower than that of the bulk SnTe, which may arise from the enhanced phonon - surface boundary scattering and phonon-defect scattering. Lastly, temperature dependent figure of merit ZT was determined for individual nanowires and the achieved maximum value at room temperature is about three times higher than that in bulk samples of comparable carrier density.« less

Minimizing the Spread in Per-Pupil Expenditures in School Finance Programs.

ERIC Educational Resources Information Center

Bruno, James E.

This paper summarizes a recent study of a mathematical approach to the allocation of State resources to local school districts. The purpose of this approach is to (1) assure the maximum utilization of resources available, (2) distribute State funds in accordance with the criteria of effectiveness imposed on the system, and (3) satisfy the…
Acer spicatum

Treesearch

Paula M. Pijut

2004-01-01

Mountain maple is a tall, deciduous shrub or clumped small tree that grows 3 to 10 m tall and can spread to form dense thickets (Dirr 1998; Gleason and Cronquist 1991; van Gelderen and others 1994). In the northern part of its native range mountain maple reaches a maximum height of 6 m (Sullivan 1993). Leaves are opposite, simple, threelobed or obscurely five-lobed,...
Multiple Maximum Exposure Rates in Computerized Adaptive Testing

ERIC Educational Resources Information Center

Ramon Barrada, Juan; Veldkamp, Bernard P.; Olea, Julio

2009-01-01

Computerized adaptive testing is subject to security problems, as the item bank content remains operative over long periods and administration time is flexible for examinees. Spreading the content of a part of the item bank could lead to an overestimation of the examinees' trait level. The most common way of reducing this risk is to impose a…
Numerical Investigation of the Influence of the Input Air Irregularity on the Performance of Turbofan Jet Engine

NASA Astrophysics Data System (ADS)

Novikova, Y.; Zubanov, V.

2018-01-01

The article describes the numerical investigation of the input air irregularity influence of turbofan engine on its characteristics. The investigated fan has a wide-blade, an inlet diameter about 2 meters, a pressure ratio about 1.6 and the bypass ratio about 4.8. The flow irregularity was simulated by the flap input in the fan inlet channel. Input of flap was carried out by an amount of 10 to 22,5% of the input channel diameter with increments of 2,5%. A nonlinear harmonic analysis (NLH-analysis) of NUMECA Fine/Turbo software was used to study the flow irregularity. The behavior of the calculated LPC characteristics repeats the experiment behavior, but there is a quantitative difference: the calculated efficiency and pressure ratio of booster consistent with the experimental data within 3% and 2% respectively, the calculated efficiency and pressure ratio of fan duct - within 4% and 2.5% respectively. An increasing the level of air irregularity in the input stage of the fan reduces the calculated mass flow, maximum pressure ratio and efficiency. With the value of flap input 12.5%, reducing the maximum air flow is 1.44%, lowering the maximum pressure ratio is 2.6%, efficiency decreasing is 3.1%.
Rock spatial densities on the rims of the Tycho secondary craters in Mare Nectaris

NASA Astrophysics Data System (ADS)

Basilevsky, A. T.; Michael, G. G.; Kozlova, N. A.

2018-04-01

The aim of this work is to check whether the technique of estimation of age of small lunar craters based on spatial density of rock boulders on their rims described in Basilevsky et al. (2013, 2015b) and Li et al. (2017) for the craters < 1 km in diameter is applicable to the larger craters. The work presents the rock counts on the rims of four craters having diameters 1000, 1100, 1240 and 1400 m located in Mare Nectaris. These craters are secondaries of the primary crater Tycho, whose age was found to be 109 ± 4 Ma (Stoffler and Ryder, 2001) so this may be taken as the age of the four craters, too. Using the dependence of the rock spatial densities at the crater rims on the crater age for the case of mare craters (Li et al., 2017) our measured rock densities correspond to ages from ∼100 to 130 Ma. These estimates are reasonably close to the given age of the primary crater Tycho. This, in turn, suggests that this technique of crater age estimation is applicable to craters up to ∼1.5 km in diameter. For the four considered craters we also measured their depth/diameter ratios and the maximum angles of the crater inner slopes. For the considered craters it was found that with increasing crater diameter, the depth/diameter ratios and maximum angles of internal slopes increase, but the values of these parameters for specific craters may deviate significantly from the general trends. The deviations probably result from some dissimilarities in the primary crater geometries, that may be due to crater to crater differences in characteristics of impactors (e.g., in their bulk densities) and/or differences in the mechanical properties of the target. It may be possible to find secondaries of crater Tycho in the South pole area and, if so, they may be studied to check the specifics and rates of the rock boulder degradation in the lunar polar environment.
Thrust and pumping characteristics of cylindrical ejectors using afterburning turbojet gas generator

NASA Technical Reports Server (NTRS)

Samanich, N. E.; Huntley, S. C.

1969-01-01

Static tests of cylindrical ejectors having ejector to primary diameter ratios from 1.1 to 1.6 and ejector length to primary nozzle diameter ratios from 0.9 to 2.1 are reported. Power setting of the J85-13 turbojet engine was varied from part power to maximum afterburning. Corrected secondary weight flow ratio was varied from 0.02 to 0.08 over a range of exhaust nozzle pressure ratios from 2.0 to 9.0. Secondary flow temperature rise and pressure drop characteristics through the nacelle secondary flow passage were also obtained.
Data book for 12.5-inch diameter SRB thermal model water flotation test - 14.7 psia, series P024

NASA Technical Reports Server (NTRS)

Allums, S. L.

1974-01-01

Tests were conducted to determine how thermal conditions affect space shuttle solid rocket booster (SRB) flotation. Acceleration, pressure, and temperature data were recorded from initial water impact to final flotation position using a 12.5-inch diameter thermal model of the SRB at ambient pressure. The model was 136.9 inches long and weighed 117.3 lbm. The tests indicated the following differences from ambient temperature tests: (1) significant negative static pressures can occur during penetration; (2) maximum penetration is increased; and (3) final flotation is in the spar buoy mode.
Large inert-gas thrusters

NASA Technical Reports Server (NTRS)

Kaufman, H. R.; Robinson, R. S.

1981-01-01

Using present technology as a starting point, performance predictions were made for large thrusters. The optimum beam diameter for maximum thruster efficiency was determined for a range of specific impulse. This optimum beam diameter varied greatly with specific impulse, from about 0.6 m at 3000 seconds (and below) to about 4 m at 10,000 seconds with argon, and from about 0.6 m at 2,000 seconds (and below) to about 12 m at 10,000 seconds with Xe. These beams sizes would require much larger thrusters than those presently available, but would offer substantial complexity and cost reductions for large electric propulsion systems.
Flight Tests Results from Supersonic Deployment of an 18-Foot Diameter (5.49 meter) Towed Ballute Decelerator

NASA Technical Reports Server (NTRS)

Mayhue, Robert J.; Eckstrom, Clinton V.

1969-01-01

A ram-air-inflated, towed ballute decelerator having a maximum frontal diameter of 18 feet (5.49 meters) was deployed during free flight at a Mach number of 3.15 and a dynamic pressure of 38.5 lb/ft(exp 2) (1843.4 newtons/m(exp 2)). Deployment and extraction of the test ballute were normal but inflation stopped about 1 second after mortar firing and produced an average plateau drag force of 1500 pounds (6.7 kN) for about 1 second. Approximately 30 percent of expected total frontal area was obtained.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Kishino, Katsumi, E-mail: kishino@sophia.ac.jp; Sophia Nanotechnology Research Center, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554; Ishizawa, Shunsuke

Bottom-up grown structurally graded InGaN-based nanocolumn photonic crystals, in which nanocolumns were arranged in triangular lattice and the nanocolumn diameter changed one-dimensionally from 93 to 213 nm with a fixed lattice constant of 250 nm, were fabricated. The spatial distribution of the diameter resulted in random-laser-like operation under optical excitation. A broad multi-wavelength lasing spectrum with more than 10 peaks was obtained with a full width at half maximum of 27 nm at 505 nm wavelength as well as lowering of the polarization degree, which is expected to be suitable for speckle contrast reduction in laser projection display applications.
A 100 electrode intracortical array: structural variability.

PubMed

Campbell, P K; Jones, K E; Normann, R A

1990-01-01

A technique has been developed for fabricating three dimensional "hair brush" electrode arrays from monocrystalline silicon blocks. Arrays consist of a square pattern of 100 penetrating electrodes, with 400 microns interelectrode spacing. Each electrode is 1.5mm in length and tapers from about 100 microns at its base to a sharp point at the tip. The tips of each electrode are coated with platinum and the entire structure, with the exception of the tips, is insulated with polyimide. Electrical connection to selected electrodes is made by wire bonding polyimide insulated 25 microns diameter gold lead wires to bonding pads on the rear surface of the array. As the geometrical characteristics of the electrodes in such an aray will influence their electrical properties (such as impedance, capacitance, spreading resistance in an electrolyte, etc.) it is desirable that such an array have minimal variability in geometry from electrode to electrode. A study was performed to determine the geometrical variability resulting from our micromachining techniques. Measurements of the diameter of each of the 100 electrodes were made at various planes above the silicon substrate of the array. For the array that was measured, the standard deviation of the diameters was approximately 9% of the mean diameter near the tip, 8% near the middle, and 6% near the base. We describe fabrication techniques which should further reduce these variabilities.
Image quality comparison of two multifocal IOLs: influence of the pupil.

PubMed

García-Domene, Mari Carmen; Felipe, Adelina; Peris-Martínez, Cristina; Navea, Amparo; Artigas, Jose M; Pons, Álvaro M

2015-04-01

To evaluate the effect of pupil size on image quality of a sectorial multifocal intraocular lens (IOL), the Lentis Mplus (Oculentis GmbH, Berlin, Germany), and the Acri.LISA IOL (Carl Zeiss Meditec, Jena, Germany). The authors measured the MTFs of the Lentis Mplus LS-312 IOL and the Acri.LISA 366D IOL with three different sizes of pupil diameters: 3, 4, and 5 mm. The MTF was calculated from the cross-line spread function recorded with the OPAL Vector System (Image Science Ltd., Oxford, UK) by using fast Fourier-transform techniques. In distance focus, the image quality provided by the Lentis Mplus IOL was better than that of the Acri. LISA IOL with all pupil diameters. In near focus, the MTF of the Acri.LISA IOL was better with a 3-mm pupil, but poor with larger pupils. The aberration effect was equal in both IOLs in distance focus, but in near focus and with a 3-mm pupil, the Acri.LISA IOL was less affected by the aberration than the Lentis Mplus IOL. The Lentis Mplus IOL provides better distance image quality than the Acri.LISA IOL, whereas the near image quality of the Acri.LISA IOL is better with small-pupil diameter. The sectorial design makes this IOL more suitable for patients with a pupil diameter greater than 3 mm. Copyright 2015, SLACK Incorporated.
Modeling and optimization of gelatin-chitosan micro-carriers preparation for soft tissue engineering: Using Response Surface Methodology.

PubMed

Radaei, Payam; Mashayekhan, Shohreh; Vakilian, Saeid

2017-06-01

Electrospray ionization is a wide spread technique for producing polymeric microcarriers (MCs) by applying electrostatic force and ionic cross-linker, simultaneously. In this study, fabrication process of gelatin-chitosan MCs and its optimization using the Response Surface Methodology (RSM) is reported. Gelatin/chitosan (G/C) blend ratio, applied voltage and feeding flow rate, their individual and interaction effects on the diameter and mechanical strength of the MCs were investigated. The obtained models for diameter and mechanical strength of MCs have a quadratic relationship with G/C blend ratio, applied voltage and feeding flow rate. Using the desirability curve, optimized G/C blend ratios that are introduced, include the desirable quantities for MCs diameter and mechanical strength. MCs of the same desirable diameter (350μm) and different G/C blend ratio (1, 2, and 3) were fabricated and their elasticity was investigated via Atomic Force Microscopy (AFM). The biocompatibility of the MCs was evaluated using MTT assay. The results showed that human Umbilical Cord Mesenchymal Stem Cells (hUCMSCs) could attach and proliferate on fabricated MCs during 7days of culturing especially on those prepared with G/C blend ratios of 1 and 2. Such gelatin-chitosan MCs may be considered as a promising candidate for injectable tissue engineering scaffolds, supporting attachment and proliferation of hUCMSCs. Copyright © 2017 Elsevier B.V. All rights reserved.
Simultaneous droplet impingement dynamics and heat transfer on nano-structured surfaces

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

Shen, Jian; Graber, Christof; Liburdy, James

This study examines the hydrodynamics and temperature characteristics of distilled deionized water droplets impinging on smooth and nano-structured surfaces using high speed (HS) and infrared (IR) imaging at We = 23.6 and Re = 1593, both based on initial drop impingement parameters. Results for a smooth and nano-structured surface for a range of surface temperatures are compared. Droplet impact velocity, transient spreading diameter and dynamic contact angle are measured. The near surface average droplet fluid temperatures are evaluated for conditions of evaporative cooling and boiling. Also included are surface temperature results using a gold layered IR opaque surface on silicon.more » Four stages of the impingement process are identified: impact, boiling, near constant surface diameter evaporation, and final dry-out. For the boiling conditions there is initial nucleation followed by severe boiling, then near constant diameter evaporation resulting in shrinking of the droplet height. When a critical contact angle is reached during evaporation the droplet rapidly retracts to a smaller diameter reducing the contact area with the surface. This continues as a sequence of retractions until final dry out. The basic trends are the same for all surfaces, but the nano-structured surface has a lower dissipated energy during impact and enhances the heat transfer for evaporative cooling with a 20% shorter time to achieve final dry out. (author)« less
Evaluation of dispersive mixing, extension rate and bubble size distribution using numerical simulation of a non-Newtonian fluid in a twin-screw mixer

NASA Astrophysics Data System (ADS)

Rathod, Maureen L.

Initially 3D FEM simulation of a simplified mixer was used to examine the effect of mixer configuration and operating conditions on dispersive mixing of a non-Newtonian fluid. Horizontal and vertical velocity magnitudes increased with increasing mixer speed, while maximum axial velocity and shear rate were greater with staggered paddles. In contrast, parallel paddles produced an area of efficient dispersive mixing between the center of the paddle and the barrel wall. This study was expanded to encompass the complete nine-paddle mixing section using power-law and Bird-Carreau fluid models. In the center of the mixer, simple shear flow was seen, corresponding with high [special character omitted]. Efficient dispersive mixing appeared near the barrel wall at all flow rates and near the barrel center with parallel paddles. Areas of backflow, improving fluid retention time, occurred with staggered paddles. The Bird-Carreau fluid showed greater influence of paddle motion under the same operating conditions due to the inelastic nature of the fluid. Shear-thinning behavior also resulted in greater maximum shear rate as shearing became easier with decreasing fluid viscosity. Shear rate distributions are frequently calculated, but extension rate calculations have not been made in a complex geometry since Debbaut and Crochet (1988) defined extension rate as the ratio of the third to the second invariant of the strain rate tensor. Extension rate was assumed to be negligible in most studies, but here extension rate is shown to be significant. It is possible to calculate maximum stable bubble diameter from capillary number if shear and extension rates in a flow field are known. Extension rate distributions were calculated for Newtonian and non-Newtonian fluids. High extension and shear rates were found in the intermeshing region. Extension is the major influence on critical capillary number and maximum stable bubble diameter, but when extension rate values are low shear rate has a larger impact. Examination of maximum stable bubble diameter through the mixer predicted areas of higher bubble dispersion based on flow type. This research has advanced simulation of non-Newtonian fluid and shown that direct calculation of extension rate is possible, demonstrating the effect of extension rate on bubble break-up.
Does pan diameter influence carbon monoxide levels during heating of water to boiling point with a camping stove?

PubMed

Leigh-Smith, Simon; Stevenson, Richard; Watt, Martin; Watt, Ian; McFadyen, Angus; Grant, Stan

2004-01-01

To determine whether pan diameter influences carbon monoxide (CO) concentration during heating of water to boiling point with a camping stove. The hypothesis was that increasing pan diameter increases CO concentration because of greater flame dispersal and a larger flame. This was a randomized, prospective study. A Coleman Dual Fuel 533 stove was used to heat pans of water to boiling point, with CO concentration monitored every 30 seconds for 5 minutes. The stove was inside a partially ventilated 200-L cardboard box model that was inside an environmental chamber at -6 degrees C. Water temperature, water volume, and flame characteristics were all standardized. Ten trials were performed for each of 2 pan diameters (base diameters of 165 mm [small] and 220 mm [large]). There was a significant difference (P = .002) between the pans for CO levels at each measurement interval from 60 seconds onward. These differences were markedly larger after 90 seconds, with a mean difference of 185 ppm (95% CI 115, 276 ppm) for all the results from 120 seconds onwards. This study has shown that there is significantly higher CO production with a large-diameter pan compared with a small-diameter pan. These findings were evident by using a camping stove to heat water to boiling point when a maximum blue flame was present throughout. Thus, in enclosed environments it is recommended that small-diameter pans be used in an attempt to prevent high CO levels.
Effect of punch and orifice base sizes in different push-out test setups: stress distribution analysis.

PubMed

Zanatta, Rayssa Ferreira; Barreto, Bruno de Castro Ferreira; Xavier, Tathy Aparecida; Versluis, Antheunis; Soares, Carlos José

2015-02-01

This study evaluated the influence of punch and base orifice diameters on push-out test results by means of finite element analysis (FEA). FEA was performed using 3D models of the push-out test with 3 base orifice diameters (2.5, 3.0, and 3.5 mm) and 3 punch diameters (0.5, 1.0, and 1.5 mm) using MARC/MENTAT (MSC.Software). The image of a cervical slice from a root restored with a fiberglass post was used to construct the models. The mechanical properties of dentin, post, and resin cement were obtained from the literature. Bases and punches were constructed as rigid bodies. A 10-N force was applied by the punch in the center of the post in a nonlinear contact analysis. Modified von Mises stress, maximum principal stress, as well as shear and normal stress components were calculated. Both punch and base orifice sizes influenced the stress distribution of the push-out test. Bases with larger diameters and punches with smaller diameters caused higher stress in dentin and at the dentin/cement interface. FEA showed that the diameter of the orifice base had a more significant influence on the stress distribution than did the punch diameter. For this reason, both factors should be taken into account during push-out experimental tests.
Growth, chamber building rate and reproduction time of Palaeonummulites venosus under natural conditions.

NASA Astrophysics Data System (ADS)

Kinoshita, Shunichi; Eder, Wolfgang; Wöger, Julia; Hohenegger, Johann; Briguglio, Antonino

2017-04-01

Investigations on Palaeonummulites venosus using the natural laboratory approach for determining chamber building rate, test diameter increase rate, reproduction time and longevity is based on the decomposition of monthly obtained frequency distributions based on chamber number and test diameter into normal-distributed components. The shift of the component parameters 'mean' and 'standard deviation' during the investigation period of 15 months was used to calculate Michaelis-Menten functions applied to estimate the averaged chamber building rate and diameter increase rate under natural conditions. The individual dates of birth were estimated using the inverse averaged chamber building rate and the inverse diameter increase rate fitted by the individual chamber number or the individual test diameter at the sampling date. Distributions of frequencies and densities (i.e. frequency divided by sediment weight) based on chamber building rate and diameter increase rate resulted both in a continuous reproduction through the year with two peaks, the stronger in May /June determined as the beginning of the summer generation (generation1) and the weaker in November determined as the beginning of the winter generation (generation 2). This reproduction scheme explains the existence of small and large specimens in the same sample. Longevity, calculated as the maximum difference in days between the individual's birth date and the sampling date seems to be round about one year, obtained by both estimations based on the chamber building rate and the diameter increase rate.
Finite Element Analysis of Bone Stress around Micro-Implants of Different Diameters and Lengths with Application of a Single or Composite Torque Force.

PubMed

Lu, Ying-juan; Chang, Shao-hai; Ye, Jian-tao; Ye, Yu-shan; Yu, Yan-song

2015-01-01

Stress on the bone surrounding dental micro-implants affects implant success. To compare the stress on the bone surrounding a micro-implant after application of a single force (SF) of 200 g or a composite force (CF) of 200 g and 6 N.mm torque. Finite element models were developed for micro-implant diameters of 1.2, 1.6, and 2.0 mm, and lengths of 6, 8, 10, and 12 mm and either a SF or CF was applied. The maximum equivalent stress (Max EQS) of the bone surrounding the micro-implant was determined, and the relationships among type of force, diameter, and length were evaluated. The Max EQS of the CF exceeded that of the SF (P< 0.05). The effect of force on stress was related to implant diameter, but not to implant length. The larger CF led to greater instability of the micro-implant and the effect was most pronounced at an implant diameter of 1.2 mm. The use of implant diameters of 1.6 mm and 2.0 mm produced no significant difference in implant stability when either a CF or SF was applied. When considering the use of an implant to perform three-dimensional control on the teeth, the implant diameter chosen should be > 1.2 mm.
Finite Element Analysis of Bone Stress around Micro-Implants of Different Diameters and Lengths with Application of a Single or Composite Torque Force

PubMed Central

Lu, Ying-juan; Chang, Shao-hai; Ye, Jian-tao; Ye, Yu-shan; Yu, Yan-song

2015-01-01

Background Stress on the bone surrounding dental micro-implants affects implant success. Purpose To compare the stress on the bone surrounding a micro-implant after application of a single force (SF) of 200 g or a composite force (CF) of 200 g and 6 N.mm torque. Materials and Methods Finite element models were developed for micro-implant diameters of 1.2, 1.6, and 2.0 mm, and lengths of 6, 8, 10, and 12 mm and either a SF or CF was applied. The maximum equivalent stress (Max EQS) of the bone surrounding the micro-implant was determined, and the relationships among type of force, diameter, and length were evaluated. Results The Max EQS of the CF exceeded that of the SF (P< 0.05). The effect of force on stress was related to implant diameter, but not to implant length. The larger CF led to greater instability of the micro-implant and the effect was most pronounced at an implant diameter of 1.2 mm. The use of implant diameters of 1.6 mm and 2.0 mm produced no significant difference in implant stability when either a CF or SF was applied. Conclusion When considering the use of an implant to perform three-dimensional control on the teeth, the implant diameter chosen should be > 1.2 mm. PMID:26659581

Ignition and growth modeling of detonation reaction zone experiments on single crystals of PETN and HMX

NASA Astrophysics Data System (ADS)

White, Bradley W.; Tarver, Craig M.

2017-01-01

It has long been known that detonating single crystals of solid explosives have much larger failure diameters than those of heterogeneous charges of the same explosive pressed or cast to 98 - 99% theoretical maximum density (TMD). In 1957, Holland et al. demonstrated that PETN single crystals have failure diameters of about 8 mm, whereas heterogeneous PETN charges have failure diameters of less than 0.5 mm. Recently, Fedorov et al. quantitatively determined nanosecond time resolved detonation reaction zone profiles of single crystals of PETN and HMX by measuring the interface particle velocity histories of the detonating crystals and LiF windows using a PDV system. The measured reaction zone time durations for PETN and HMX single crystal detonations were approximately 100 and 260 nanoseconds, respectively. These experiments provided the necessary data to develop Ignition and Growth (I&G) reactive flow model parameters for the single crystal detonation reaction zones. Using these parameters, the calculated unconfined failure diameter of a PETN single crystal was 7.5 +/- 0.5 mm, close to the 8 mm experimental value. The calculated failure diameter of an unconfined HMX single crystal was 15 +/- 1 mm. The unconfined failure diameter of an HMX single crystal has not yet been determined precisely, but Fedorov et al. detonated 14 mm diameter crystals confined by detonating a HMX-based plastic bonded explosive (PBX) without initially overdriving the HMX crystals.
Reversals and collisions optimize protein exchange in bacterial swarms

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

Amiri, Aboutaleb; Harvey, Cameron; Buchmann, Amy

Swarming groups of bacteria coordinate their behavior by self-organizing as a population to move over surfaces in search of nutrients and optimal niches for colonization. Many open questions remain about the cues used by swarming bacteria to achieve this self-organization. While chemical cue signaling known as quorum sensing is well-described, swarming bacteria often act and coordinate on time scales that could not be achieved via these extracellular quorum sensing cues. Here, cell-cell contact-dependent protein exchange is explored as amechanism of intercellular signaling for the bacterium Myxococcus xanthus. A detailed biologically calibrated computational model is used to study how M. xanthusmore » optimizes the connection rate between cells and maximizes the spread of an extracellular protein within the population. The maximum rate of protein spreading is observed for cells that reverse direction optimally for swarming. Cells that reverse too slowly or too fast fail to spread extracellular protein efficiently. In particular, a specific range of cell reversal frequencies was observed to maximize the cell-cell connection rate and minimize the time of protein spreading. Furthermore, our findings suggest that predesigned motion reversal can be employed to enhance the collective behavior of biological synthetic active systems.« less
How applicable is uneven-age management in northern forest types?

Treesearch

Stanley M. Filip

1977-01-01

For the proper application and practice of uneven-age management, one must consider residual stocking, maximum tree-size objective, and diameter distribution. All three components are described, and it is shown how they fit into a practical package for application in a timber tract.
29 CFR 1910.211 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... inches diameter and larger, specially designed for use on cutting-off machines where mounting nut or... enclosure designed to restrain the pieces of the grinding wheel and furnish all possible protection in the... designed and fully guarded machines and are subject to the following maximum thickness and hole size...
Flow-field characteristics of high-temperature annular buoyant jets and their development laws influenced by ventilation system.

PubMed

Wang, Yi; Huang, Yanqiu; Liu, Jiaping; Wang, Hai; Liu, Qiuhan

2013-01-01

The flow-field characteristics of high-temperature annular buoyant jets as well as the development laws influenced by ventilation system were studied using numerical methods to eliminate the pollutants effectively in this paper. The development laws of high-temperature annular buoyant jets were analyzed and compared with previous studies, including radial velocity distribution, axial velocity and temperature decay, reattachment position, cross-section diameter, volumetric flow rate, and velocity field characteristics with different pressures at the exhaust hood inlet. The results showed that when the ratio of outer diameter to inner diameter of the annulus was smaller than 5/2, the flow-field characteristics had significant difference compared to circular buoyant jets with the same outer diameter. For similar diameter ratios, reattachment in this paper occurred further downstream in contrast to previous study. Besides, the development laws of volumetric flow rate and cross-section diameter were given with different initial parameters. In addition, through analyzing air distribution characteristics under the coupling effect of high-temperature annular buoyant jets and ventilation system, it could be found that the position where maximum axial velocity occurred was changing gradually when the pressure at the exhaust hood inlet changed from 0 Pa to -5 Pa.
Flow-Field Characteristics of High-Temperature Annular Buoyant Jets and Their Development Laws Influenced by Ventilation System

PubMed Central

Liu, Jiaping; Wang, Hai; Liu, Qiuhan

2013-01-01

The flow-field characteristics of high-temperature annular buoyant jets as well as the development laws influenced by ventilation system were studied using numerical methods to eliminate the pollutants effectively in this paper. The development laws of high-temperature annular buoyant jets were analyzed and compared with previous studies, including radial velocity distribution, axial velocity and temperature decay, reattachment position, cross-section diameter, volumetric flow rate, and velocity field characteristics with different pressures at the exhaust hood inlet. The results showed that when the ratio of outer diameter to inner diameter of the annulus was smaller than 5/2, the flow-field characteristics had significant difference compared to circular buoyant jets with the same outer diameter. For similar diameter ratios, reattachment in this paper occurred further downstream in contrast to previous study. Besides, the development laws of volumetric flow rate and cross-section diameter were given with different initial parameters. In addition, through analyzing air distribution characteristics under the coupling effect of high-temperature annular buoyant jets and ventilation system, it could be found that the position where maximum axial velocity occurred was changing gradually when the pressure at the exhaust hood inlet changed from 0 Pa to −5 Pa. PMID:24000278
Effect of Nd:YAG laser parameters on the penetration depth of a representative Ni-Cr dental casting alloy.

PubMed

Al Jabbari, Youssef S; Koutsoukis, Theodoros; Barmpagadaki, Xanthoula; El-Danaf, Ehab A; Fournelle, Raymond A; Zinelis, Spiros

2015-02-01

The effects of voltage and laser beam (spot) diameter on the penetration depth during laser beam welding in a representative nickel-chromium (Ni-Cr) dental alloy were the subject of this study. The cast alloy specimens were butted against each other and laser welded at their interface using various voltages (160-390 V) and spot diameters (0.2-1.8 mm) and a constant pulse duration of 10 ms. After welding, the laser beam penetration depths in the alloy were measured. The results were plotted and were statistically analyzed with a two-way ANOVA, employing voltage and spot diameter as the discriminating variables and using Holm-Sidak post hoc method (a = 0.05). The maximum penetration depth was 4.7 mm. The penetration depth increased as the spot diameter decreased at a fixed voltage and increased as the voltage increased at a fixed spot diameter. Varying the parameters of voltage and laser spot diameter significantly affected the depth of penetration of the dental cast Ni-Cr alloy. The penetration depth of laser-welded Ni-Cr dental alloys can be accurately adjusted based on the aforementioned results, leading to successfully joined/repaired dental restorations, saving manufacturing time, reducing final cost, and enhancing the longevity of dental prostheses.
In vitro large diameter bowel anastomosis using a temperature controlled laser tissue soldering system and albumin stent.

PubMed

Spector, David; Rabi, Yaron; Vasserman, Irena; Hardy, Amos; Klausner, Joseph; Rabau, Micha; Katzir, Abraham

2009-09-01

In today's age of advancing surgical technology, there is a need for better and simpler methods of tissue bonding. The use of lasers for tissue welding or soldering is one of these sutureless methods. In 30 years of laser tissue bonding (LTB) research, published reports of cylindrical organ anastomosis were limited to small diameters. The tension resisted by the anastomosis, which is caused by the intraluminal pressure, is also proportional to the organ diameter. Therefore the anastomosis of large diameter organs requires significantly stronger mechanical strength. The aim of this study is to demonstrate such an anastomosis. In vitro anastomosis of porcine small bowel was performed by either LTB or sutures. Anastomosis in the laser group (number of samples, n = 15) included two main stages of soldering. The bowel edges were approximated over a solid albumin stent and heated with a temperature controlled GaAs laser system to 75 degrees C. This was followed by spreading liquid albumin on the anastomotic line and heating by the same system again to 75 degrees C. The control group (n = 5) was sutured anastomosis. All anastomoses were assessed by burst pressure measurement. The burst pressure of the laser group attained 170+/-40 mmHg which was significantly higher than that of the sutured group 83+/-37 mmHg (P < 0.001). This report describes the in vitro LTB anastomosis of a large diameter cylindrical organ. The immediate bond strength, as estimated by burst pressure measurements, was double compared to sutured anastomosis.
Dosimetric properties of a proton beamline dedicated to the treatment of ocular disease

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

Slopsema, R. L., E-mail: rslopsema@floridaproton.org; Mamalui, M.; Yeung, D.

2014-01-15

Purpose: A commercial proton eyeline has been developed to treat ocular disease. Radiotherapy of intraocular lesions (e.g., uveal melanoma, age-related macular degeneration) requires sharp dose gradients to avoid critical structures like the macula and optic disc. A high dose rate is needed to limit patient gazing times during delivery of large fractional dose. Dose delivery needs to be accurate and predictable, not in the least because current treatment planning algorithms have limited dose modeling capabilities. The purpose of this paper is to determine the dosimetric properties of a new proton eyeline. These properties are compared to those of existing systemsmore » and evaluated in the context of the specific clinical requirements of ocular treatments. Methods: The eyeline is part of a high-energy, cyclotron-based proton therapy system. The energy at the entrance of the eyeline is 105 MeV. A range modulator (RM) wheel generates the spread-out Bragg peak, while a variable range shifter system adjusts the range and spreads the beam laterally. The range can be adjusted from 0.5 up to 3.4 g/cm{sup 2}; the modulation width can be varied in steps of 0.3 g/cm{sup 2} or less. Maximum field diameter is 2.5 cm. All fields can be delivered with a dose rate of 30 Gy/min or more. The eyeline is calibrated according to the IAEA TRS-398 protocol using a cylindrical ionization chamber. Depth dose distributions and dose/MU are measured with a parallel-plate ionization chamber; lateral profiles with radiochromic film. The dose/MU is modeled as a function of range, modulation width, and instantaneous MU rate with fit parameters determined per option (RM wheel). Results: The distal fall-off of the spread-out Bragg peak is 0.3 g/cm{sup 2}, larger than for most existing systems. The lateral penumbra varies between 0.9 and 1.4 mm, except for fully modulated fields that have a larger penumbra at skin. The source-to-axis distance is found to be 169 cm. The dose/MU shows a strong dependence on range (up to 4%/mm). A linear increase in dose/MU as a function of instantaneous MU rate is observed. The dose/MU model describes the measurements with an accuracy of ±2%. Neutron dose is found to be 146 ± 102 μSv/Gy at the contralateral eye and 19 ± 13 μSv/Gy at the chest. Conclusions: Measurements show the proton eyeline meets the requirements to effectively treat ocular disease.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)

Slopsema, R. L., E-mail: rslopsema@floridaproton.org; Mamalui, M.; Yeung, D.

Purpose: A commercial proton eyeline has been developed to treat ocular disease. Radiotherapy of intraocular lesions (e.g., uveal melanoma, age-related macular degeneration) requires sharp dose gradients to avoid critical structures like the macula and optic disc. A high dose rate is needed to limit patient gazing times during delivery of large fractional dose. Dose delivery needs to be accurate and predictable, not in the least because current treatment planning algorithms have limited dose modeling capabilities. The purpose of this paper is to determine the dosimetric properties of a new proton eyeline. These properties are compared to those of existing systemsmore » and evaluated in the context of the specific clinical requirements of ocular treatments. Methods: The eyeline is part of a high-energy, cyclotron-based proton therapy system. The energy at the entrance of the eyeline is 105 MeV. A range modulator (RM) wheel generates the spread-out Bragg peak, while a variable range shifter system adjusts the range and spreads the beam laterally. The range can be adjusted from 0.5 up to 3.4 g/cm{sup 2}; the modulation width can be varied in steps of 0.3 g/cm{sup 2} or less. Maximum field diameter is 2.5 cm. All fields can be delivered with a dose rate of 30 Gy/min or more. The eyeline is calibrated according to the IAEA TRS-398 protocol using a cylindrical ionization chamber. Depth dose distributions and dose/MU are measured with a parallel-plate ionization chamber; lateral profiles with radiochromic film. The dose/MU is modeled as a function of range, modulation width, and instantaneous MU rate with fit parameters determined per option (RM wheel). Results: The distal fall-off of the spread-out Bragg peak is 0.3 g/cm{sup 2}, larger than for most existing systems. The lateral penumbra varies between 0.9 and 1.4 mm, except for fully modulated fields that have a larger penumbra at skin. The source-to-axis distance is found to be 169 cm. The dose/MU shows a strong dependence on range (up to 4%/mm). A linear increase in dose/MU as a function of instantaneous MU rate is observed. The dose/MU model describes the measurements with an accuracy of ±2%. Neutron dose is found to be 146 ± 102 μSv/Gy at the contralateral eye and 19 ± 13 μSv/Gy at the chest. Conclusions: Measurements show the proton eyeline meets the requirements to effectively treat ocular disease.« less
Insights into Corona Formation through Statistical Analyses

NASA Technical Reports Server (NTRS)

Glaze, L. S.; Stofan, E. R.; Smrekar, S. E.; Baloga, S. M.

2002-01-01

Statistical analysis of an expanded database of coronae on Venus indicates that the populations of Type 1 (with fracture annuli) and 2 (without fracture annuli) corona diameters are statistically indistinguishable, and therefore we have no basis for assuming different formation mechanisms. Analysis of the topography and diameters of coronae shows that coronae that are depressions, rimmed depressions, and domes tend to be significantly smaller than those that are plateaus, rimmed plateaus, or domes with surrounding rims. This is consistent with the model of Smrekar and Stofan and inconsistent with predictions of the spreading drop model of Koch and Manga. The diameter range for domes, the initial stage of corona formation, provides a broad constraint on the buoyancy of corona-forming plumes. Coronae are only slightly more likely to be topographically raised than depressions, with Type 1 coronae most frequently occurring as rimmed depressions and Type 2 coronae most frequently occuring with flat interiors and raised rims. Most Type 1 coronae are located along chasmata systems or fracture belts, while Type 2 coronas are found predominantly as isolated features in the plains. Coronae at hotspot rises tend to be significantly larger than coronae in other settings, consistent with a hotter upper mantle at hotspot rises and their active state.
The influence of material and mesh characteristics on transmission mode desorption electrospray ionization.

PubMed

Chipuk, Joseph E; Brodbelt, Jennifer S

2009-04-01

Adaptation of desorption electrospray ionization to a transmission mode (TM-DESI) entails passing an electrospray plume through a sample that has been deposited onto a mesh substrate. A combination of mass spectrometry and fluorescence microscopy studies is used to illustrate the critical role material composition, mesh open space, and mesh fiber diameter play on the transmission, desorption, and ionization process. Substrates with open spaces less than 150 microm and accompanying minimal strand diameters produce less scattering of the plume and therefore favor transmission. Larger strand diameters typically encompass larger open spaces, but the increase in the surface area of the strand increases plume scattering as well as solvent and analyte spreading on the mesh. Polypropylene (PP), ethylene tetrafluoroethylene (ETFE), and polyetheretherketone (PEEK) materials afford much better desorption than similarly sized polyethylene terephthalate (PETE) or nylon-6,6 (PA66) substrates. Ultimately, the manner in which the electrospray plume interacts with the mesh as it is transmitted through the substrate is shown to be critical to performing and optimizing TM-DESI analyses. In addition, evidence is presented for analyte dependent variations in the desorption mechanisms of dry and solvated samples.
New Observations of Subarcsecond Photospheric Bright Points

NASA Technical Reports Server (NTRS)

Berger, T. E.; Schrijver, C. J.; Shine, R. A.; Tarbell, T. D.; Title, A. M.; Scharmer, G.

1995-01-01

We have used an interference filter centered at 4305 A within the bandhead of the CH radical (the 'G band') and real-time image selection at the Swedish Vacuum Solar Telescope on La Palma to produce very high contrast images of subarcsecond photospheric bright points at all locations on the solar disk. During the 6 day period of 1993 September 15-20 we observed active region NOAA 7581 from its appearance on the East limb to a near-disk-center position on September 20. A total of 1804 bright points were selected for analysis from the disk center image using feature extraction image processing techniques. The measured Full Width at Half Maximum (FWHM) distribution of the bright points in the image is lognormal with a modal value of 220 km (0 sec .30) and an average value of 250 km (0 sec .35). The smallest measured bright point diameter is 120 km (0 sec .17) and the largest is 600 km (O sec .69). Approximately 60% of the measured bright points are circular (eccentricity approx. 1.0), the average eccentricity is 1.5, and the maximum eccentricity corresponding to filigree in the image is 6.5. The peak contrast of the measured bright points is normally distributed. The contrast distribution variance is much greater than the measurement accuracy, indicating a large spread in intrinsic bright-point contrast. When referenced to an averaged 'quiet-Sun' area in the image, the modal contrast is 29% and the maximum value is 75%; when referenced to an average intergranular lane brightness in the image, the distribution has a modal value of 61% and a maximum of 119%. The bin-averaged contrast of G-band bright points is constant across the entire measured size range. The measured area of the bright points, corrected for pixelation and selection effects, covers about 1.8% of the total image area. Large pores and micropores occupy an additional 2% of the image area, implying a total area fraction of magnetic proxy features in the image of 3.8%. We discuss the implications of this area fraction measurement in the context of previously published measurements which show that typical active region plage has a magnetic filling factor on the order of 10% or greater. The results suggest that in the active region analyzed here, less than 50% of the small-scale magnetic flux tubes are demarcated by visible proxies such as bright points or pores.
Production of lunar fragmental material by meteoroid impact.

NASA Technical Reports Server (NTRS)

Marcus, A. H.

1973-01-01

The rate of production of new fragmental lunar surface material is derived theoretically on the hypothesis that such material is excavated from a bedrock layer by meteoroid impacts. An overlaying regolith effectively shields the bedrock layer from small impacts, reducing the production rate of centimeter-sized and smaller blocks by a large factor. Logarithmic production rate curves for centimeter to motor-sized blocks are nonlinear for any regolith from centimeters to tens of meters in thickness, with small blocks relatively much less frequent for thicker (older) regoliths, suggesting the possibility of a statistical reverse bedding. Modest variations in the exponents of scaling laws for crater depth-diameter ratio and maximum block-diameter to crater diameter ratio are shown to have significant effects on the production rates. The production rate increases slowly with increasing size of the largest crater affecting the region.
Constraints on the diameter and albedo of 2060 Chiron

NASA Technical Reports Server (NTRS)

Sykes, Mark V.; Walker, Russell G.

1991-01-01

Asteroid 2060 Chiron is the largest known object exhibiting cometary activity. Radiometric observations made in 1983 from a ground-based telescope and the IRAS are used to examine the limits on Chiron's diameter and albedo. It is argued that Chiron's surface temperature distribution at that time is best described by an 'isothermal latitude' or 'rapid-rotator' model. Consequently, Chiron has a maximum diameter of 372 kilometers and a minimum geometric albedo of 2.7 percent. This is much bigger and darker than previous estimates, and suggests that gravity may play a significant role in the evolution of gas and dust emissions. It is also found that for large obliquities, surface temperatures can vary dramatically on time scales of a decade, and that such geometry may play a critical role in explaining Chiron's observed photometric behavior since its discovery in 1977.
Constraints on the diameter and albedo of 2060 chiron.

PubMed

Sykes, M V; Walker, R G

1991-02-15

Asteroid 2060 Chiron is the largest known object exhibiting cometary activity. Radiometric observations made in 1983 from a ground-based telescope and the Infrared Astronomical Satellite are used to examine the limits on Chiron's diameter and albedo. It is argued that Chiron's surface temperature distribution at that time is best described by an "isothermal latitude" or "rapid-rotator" model. Consequently, Chiron has a maximum diameter of 372 kilometers and a minimum geometric albedo of 2.7%. This is much bigger and darker than previous estimates, and suggests that gravity may play a significant role in the evolution of gas and dust emissions. It is also found that for large obliquities, surface temperatures can vary dramatically on time scales of a decade, and that such geometry may play a critical role in explaining Chiron's observed photometric behavior since its discovery in 1977.
Processing and characterization of oval piezoelectric actuators

NASA Astrophysics Data System (ADS)

Jadidian, B.; Allahverdi, M.; Mohammadi, F.; Safari, A.

2002-03-01

The processing and characterization of piezoelectric actuators with oval geometry are presented. The monolithic actuators were fabricated using the fused deposition of ceramic process. The minor diameter of the ovals varied between 2 and 14 mm and their major diameter, wall thickness, and width were 20, 0.85, and 7 mm, respectively. When driven under electric field, the actuators expanded along their minor diameter. The static and dynamic displacements of ˜7 and ˜5.6 μm were observed at 850 V(dc) and 100 V(ac). The static displacement of the ovals varied almost linearly with voltage and did not change under the application of external load in the range of 1-15 N. However, both dynamic displacement and resonant frequency of the ovals varied, with a maximum of 42 μm and 38 Hz, respectively, under 13 N load.
Body surface area as a key determinant of aortic root and arch dimensions in a population-based study.

PubMed

Wang, Yan-Li; Wang, Qing-Ling; Wang, Liang; Wu, Ying-Biao; Wang, Zhi-Bin; Cameron, James; Liang, Yu-Lu

2013-02-01

The associations between the aortic dimensions (of the aortic sinus, aortic annulus and aortic arch) and physiological variables have not been established in the Chinese population. The present study examined the associations among physiological variables to determine the aortic root and arch dimensions echocardiographically. The diameters of the aortic sinus, annulus and arch were measured in 1,010 subjects via 2-D echocardiography with a 3.5-MHz transducer in a trans-thoracic position. The images of the aortic sinus and aortic annulus were obtained from a standard parasternal long-axis view. The maximum diameter of the valve orifice was measured at the end of systole. The aortic arch dimension was visualized in the long-axis using a suprasternal notch window and the maximum transverse diameter was measured. Epidata 3.0, Excel 2007 and SPSS version 17.0 were used to collect and analyze the data. A total of 1,010 subjects were enrolled. The mean age was 55.0±17.0 years (range of 18 to 90 years). The body surface area (BSA) was the best predictor of all the studied physiological variables and may be used to predict aortic sinus, annulus and arch dimensions independently (r=0.54, 0.37 and 0.39, respectively). Gender, blood pressure, age and BSA are significant predictors of the aortic dimensions. Of these, BSA was the best predictor.
A systematic examination of the bone destruction pattern of the two-shot technique

PubMed Central

Stoetzer, Marcus; Stoetzer, Carsten; Rana, Majeed; Zeller, Alexander; Hanke, Alexander; Gellrich, Nils-Claudius; von See, Constantin

2014-01-01

Introduction: The two-shot technique is an effective stopping power method. The precise mechanisms of action on the bone and soft-tissue structures of the skull; however, remain largely unclear. The aim of this study is to compare the terminal ballistics of the two-shot and single-shot techniques. Materials and Methods: 40 fresh pigs’ heads were randomly divided into 4 groups (n = 10). Either a single shot or two shots were fired at each head with a full metal jacket or a semi-jacketed bullet. Using thin-layer computed tomography and photography, the diameter of the destruction pattern and the fractures along the bullet path were then imaged and assessed. Results: A single shot fired with a full metal jacket bullet causes minor lateral destruction along the bullet path. With two shots fired with a full metal jacket bullet, however, the maximum diameter of the bullet path is significantly greater (P < 0.05) than it is with a single shot fired with a full metal jacket bullet. In contrast, the maximum diameter with a semi-jacketed bullet is similar with the single-shot and two-shot techniques. Conclusion: With the two-shot technique, a full metal jacket bullet causes a destruction pattern that is comparable to that of a single shot fired with a semi-jacketed bullet. PMID:24812454
Abdominal aortic aneurysm and the association with serum levels of Homocysteine, vitamins B6, B12 and Folate

PubMed Central

Lindqvist, Markus; Hellström, Anders; Henriksson, Anders E

2012-01-01

Previous investigations have shown hyperhomocysteinemi in patients with abdominal aortic aneurysm (AAA). In the present study we evaluated the circulating level of homocysteine (Hcy) in relation to renal function, vitamins B6, B12 and folate status in AAA patients with special regard to aneurysm size, and rupture. Hcy, Creatinine, B6, B12 and folate were measured in 119 patients with AAA and 36 controls without aneurysm matched by age, gender and smoking habit. As expected there was a weak correlation between Hcy and vitamins B6, B12 or folate. We found similar levels of Hcy, B6 and folic acid in patients with nonruptured AAA compared to the control group matched by age, gender and smoking habit. There was no correlation between maximum diameter of the nonruptured AAA (n=78) and Hcy, B6 or folate. However, the present study shows a significant inverse correlation between maximum diameter of the nonruptured AAA (n=78) and B12 (r = -0.304, p=0.007) with significant higher levels in small AAA compared to large AAA. In conclusion, Hcy does not seem to be a useful biomarker in AAA disease. The unexpected finding of B12 levels correlating to aneurysm diameter warrants urgent further investigation of B12 supplement to prevent progression of small AAA. PMID:23173106

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