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Sample records for designed wall thickness

  1. Wall thickness design and corrosion management

    SciTech Connect

    Gestel, W.M. van; Guijt, J.

    1994-12-31

    In 1995, Norske Shell will install two 36-in. sweet wet gas pipe lines in the Norwegian sector of the North Sea. The lines cross the Norwegian trench with water depths up to 350 meter. For the last 3.5 km. of the route the pipelines will be laid in a tunnel which will be flooded after construction. The two lines will transport largely untreated well fluids from the Troll field to an onshore processing plant at Kollsness, North of Bergen. From there sales gas will be transported to the continent via the Furopipe and Zeepipe systems. Gas contracts covering 30 years have been concluded with gas utilities on the continent. The maximum wall thickness that could be installed was limited by the capabilities of the present generation of lay barges and pipe mill capacities. The over-thickness, i.e. beyond that what is required for pressure containment and external collapse, is available as corrosion allowance. The paper discusses a novel probabilistic approach to define the corrosion control measures. The corrosion control system is based on the injection of glycol for corrosion mitigation and inspection by ultrasonic internal smart pigs, which in combination with identified fall back options, ensure a minimum 50 year service life.

  2. Tube wall thickness measurement apparatus

    DOEpatents

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  3. Tube wall thickness measurement apparatus

    DOEpatents

    Lagasse, Paul R.

    1987-01-01

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  4. Turbine airfoil with outer wall thickness indicators

    DOEpatents

    Marra, John J; James, Allister W; Merrill, Gary B

    2013-08-06

    A turbine airfoil usable in a turbine engine and including a depth indicator for determining outer wall blade thickness. The airfoil may include an outer wall having a plurality of grooves in the outer surface of the outer wall. The grooves may have a depth that represents a desired outer surface and wall thickness of the outer wall. The material forming an outer surface of the outer wall may be removed to be flush with an innermost point in each groove, thereby reducing the wall thickness and increasing efficiency. The plurality of grooves may be positioned in a radially outer region of the airfoil proximate to the tip.

  5. Design and preliminary tests of a family of adaptive waveforms to measure blood vessel diameter and wall thickness.

    PubMed

    Ai, Yuhui; Jaffe, Jules S

    2005-02-01

    In this article we consider the adaptive design of waveforms to be used in vascular ultrasound. The advantage of these waveforms, when used with the proposed processing scheme, is that their application results in increased reflected energy, especially when compared with more conventional methods such as a short-gated sinusoid. This increase in reflected energy has potential to permit inferences to be made about wall thickness and vessel diameter from deeper vessels than possible with more traditional techniques. Here, the use of waveforms of the type A(t)ej(kt2), 0 < or = t < or = b, where A(t) is a specially designed envelope and k a sweep frequency, is proposed. Theorems are proved that describe how to choose an A(t) which results in either a maximum of reflected energy signal-to-noise ratio (SNR), or range resolution. The design of the waveform is adaptive in that both A(t) and k are derived in consideration of a specific blood vessel whose transfer function has been obtained experimentally. Numerical simulations illustrate the advantages of using these waveforms as well as the effects of the parameters. A simple experimental implementation of the methodology is presented on a brachial artery. The measurement of the impulse response of the artery is presented in this context. Results indicate that a processing gain in SNR over the instantaneous values obtained from the raw echo waveforms of 11 dB to 14 dB can be obtained via this methodology.

  6. Tube-Wall Thickness Detector

    NASA Technical Reports Server (NTRS)

    Kleint, R. E.; Baily, R. D.

    1985-01-01

    Eddy-current measurements detect wear of thin walls (0.01 in) (0.25 mm) in small diameter (0.19 in) (5 mm) heat exchanger tubing. Flexible durable thin rod inserts eddy-current coil into the heatexchanger tube.

  7. Tube-Wall Thickness Detector

    NASA Technical Reports Server (NTRS)

    Kleint, R. E.; Baily, R. D.

    1985-01-01

    Eddy-current measurements detect wear of thin walls (0.01 in) (0.25 mm) in small diameter (0.19 in) (5 mm) heat exchanger tubing. Flexible durable thin rod inserts eddy-current coil into the heatexchanger tube.

  8. Wall thickness measuring method and apparatus

    DOEpatents

    Salzer, Leander J.; Bergren, Donald A.

    1989-01-01

    An apparatus for measuring the wall thickness of a nonmagnetic article having a housing supporting a magnet and a contiguous supporting surface. The tubular article and the housing are releasably secured to the supporting surface and a support member of an optical comparator, respectively. To determine the wall thickness of the article at a selected point, a magnetically responsive ball is positioned within the tubular article over said point and retained therein by means of a magnetic field produced by the magnet. Thereafter, an optical comparator is employed to project a magnified image of the ball on a screen and the wall thickness at the selected point is calculated by using a ball surface measurement taken with the comparator in conjunction with a previously determined base line measurement.

  9. Reproducibility of airway wall thickness measurements

    NASA Astrophysics Data System (ADS)

    Schmidt, Michael; Kuhnigk, Jan-Martin; Krass, Stefan; Owsijewitsch, Michael; de Hoop, Bartjan; Peitgen, Heinz-Otto

    2010-03-01

    Airway remodeling and accompanying changes in wall thickness are known to be a major symptom of chronic obstructive pulmonary disease (COPD), associated with reduced lung function in diseased individuals. Further investigation of this disease as well as monitoring of disease progression and treatment effect demand for accurate and reproducible assessment of airway wall thickness in CT datasets. With wall thicknesses in the sub-millimeter range, this task remains challenging even with today's high resolution CT datasets. To provide accurate measurements, taking partial volume effects into account is mandatory. The Full-Width-at-Half-Maximum (FWHM) method has been shown to be inappropriate for small airways1,2 and several improved algorithms for objective quantification of airway wall thickness have been proposed.1-8 In this paper, we describe an algorithm based on a closed form solution proposed by Weinheimer et al.7 We locally estimate the lung density parameter required for the closed form solution to account for possible variations of parenchyma density between different lung regions, inspiration states and contrast agent concentrations. The general accuracy of the algorithm is evaluated using basic tubular software and hardware phantoms. Furthermore, we present results on the reproducibility of the algorithm with respect to clinical CT scans, varying reconstruction kernels, and repeated acquisitions, which is crucial for longitudinal observations.

  10. On thick domain walls in general relativity

    NASA Technical Reports Server (NTRS)

    Goetz, Guenter; Noetzold, Dirk

    1989-01-01

    Planar scalar field configurations in general relativity differ considerably from those in flat space. It is shown that static domain walls of finite thickness in curved space-time do not possess a reflection symmetry. At infinity, the space-time tends to the Taub vacuum on one side of the wall and to the Minkowski vacuum (Rindler space-time) on the other. Massive test particles are always accelerated towards the Minkowski side, i.e., domain walls are attractive on the Taub side, but repulsive on the Minkowski side (Taub-vacuum cleaner). It is also proved that the pressure in all directions is always negative. Finally, a brief comment is made concerning the possibility of infinite, i.e., bigger than horizon size, domain walls in our universe. All of the results are independent of the form of the potential V(phi) greater than or equal to 0 of the scalar field phi.

  11. Gas turbine bucket wall thickness control

    DOEpatents

    Stathopoulos, Dimitrios; Xu, Liming; Lewis, Doyle C.

    2002-01-01

    A core for use in casting a turbine bucket including serpentine cooling passages is divided into two pieces including a leading edge core section and a trailing edge core section. Wall thicknesses at the leading edge and the trailing edge of the turbine bucket can be controlled independent of each other by separately positioning the leading edge core section and the trailing edge core section in the casting die. The controlled leading and trailing edge thicknesses can thus be optimized for efficient cooling, resulting in more efficient turbine operation.

  12. Hot Wall Thickness Variation Measurement System

    DTIC Science & Technology

    1979-06-01

    Subtltia) HOT WALL THICKNESS VARIATION MEASUREMENT SYSTEM 7. AUTHORfa; 3. J. KRUPSKI 9 . PERFORMING ORGANIZATION NAME AND ADDRESS PRODUCT...THE FORGING 3. ULTRASONICS ON A HOT TUBE 4. SYSTEt-l DESCRIPTION 5. TESTING RESULTS 6. CONCLUSIONS 7. HffLEMENTATION PAGE i ii 1 2 4 6 9 ...printed out. The grip procedure was repeated toward the breech end of the forging with good results. The third and 9 breech end prints were at about

  13. Occlusion-free Blood Flow Animation with Wall Thickness Visualization.

    PubMed

    Lawonn, Kai; Glaßer, Sylvia; Vilanova, Anna; Preim, Bernhard; Isenberg, Tobias

    2016-01-01

    We present the first visualization tool that combines pathlines from blood flow and wall thickness information. Our method uses illustrative techniques to provide occlusion-free visualization of the flow. We thus offer medical researchers an effective visual analysis tool for aneurysm treatment risk assessment. Such aneurysms bear a high risk of rupture and significant treatment-related risks. Therefore, to get a fully informed decision it is essential to both investigate the vessel morphology and the hemodynamic data. Ongoing research emphasizes the importance of analyzing the wall thickness in risk assessment. Our combination of blood flow visualization and wall thickness representation is a significant improvement for the exploration and analysis of aneurysms. As all presented information is spatially intertwined, occlusion problems occur. We solve these occlusion problems by dynamic cutaway surfaces. We combine this approach with a glyph-based blood flow representation and a visual mapping of wall thickness onto the vessel surface. We developed a GPU-based implementation of our visualizations which facilitates wall thickness analysis through real-time rendering and flexible interactive data exploration mechanisms. We designed our techniques in collaboration with domain experts, and we provide details about the evaluation of the technique and tool.

  14. Wall thickness effect on the resistive wall mode stability in toroidal plasmas

    SciTech Connect

    Zheng, L.-J.; Kotschenreuther, M.T.

    2005-07-15

    The effect of finite wall thickness on the stability of n=1 resistive wall modes in toroidal plasmas is investigated. A fusion reactor-relevant configuration is examined. The investigation employs a novel ideal-magnetohydrodynamics adaptive shooting code for axisymmetric plasmas, extended to take into account the wall thickness. Although finite wall thickness generally reduces the growth rate of the resistive wall modes, no contribution to stabilization is found to be made by the portion of the wall that is located beyond the critical position for perfectly conducting wall stabilization. Thus, when the inner side of the wall lies near the critical wall position, the scaling of the growth rate versus wall thickness in the realistic thick-wall calculation is significantly different from that of the usual thin-wall theory. The thin-wall estimate is relevant only when the wall is brought very close to the plasma and is not too thick.

  15. Multilayer injection moulding of thick-walled optical plastics parts

    NASA Astrophysics Data System (ADS)

    Hopmann, Ch.; Neuss, A.; Weber, M.; Walach, P.

    2014-05-01

    Optical components are often thick-walled. The cycle time of precise polymer optics with a wall thickness of more than 20 mm exceeds several minutes. The multilayer injection moulding or compression moulding lowers the cycle time and increases the quality of the moulded parts. For the production of multilayer moulded lenses the mould design plays an important role. An innovative mould concept is presented with the possiblity to produce double or triple layer lenses. To ensure the quality and the endurance of multilayer moulded optical components in their applications, the cohesion in the interface is important. Tensile shear tests show the ability of multilayer moulded parts with high cohesion values for optical applications.

  16. Thick-wall Kevlar 49/Epoxy pressure vessels

    SciTech Connect

    Guess, T.R.

    1984-01-01

    The feasibility of thick-wall composite vessels for very high pressure applications is demonstrated. Prototype vessels, in both spherical and cylindrical geometries, were designed, fabricated and burst tested. It is shown that experimental burst pressures are in excellent agreement with predicted values for burst pressures up to 60 ksi. Each unit consisted of a thin, seamless, copper liner with stainless steel fill stems and a filament-wound Kevlar 49/epoxy outer shell. Analysis of vessel performance accounted for liner thickness and yield strengths, composite thickness, mechanical properties and fiber volume fraction, and stress concentrations caused by the fill stem. Spherical vessels of three different sizes (inside diameters of 2.15 inches, 4.0 inches and 5.3 inches) with either 30 ksi or 60 ksi design burst pressure are discussed. Also, cylindrical vessels with identical liners but of two different composite thicknesses are described. These vessels achieved 50 ksi and 57 ksi burst pressures, respectively. In addition to the design considerations alluded to throughout the paper, the stress state in a thin metal liner during cyclic loading and the life prediction of composite vessels under sustained loading are discussed.

  17. Myocardium wall thickness transducer and measuring method

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Lewis, G. W.; Silver, R. H.; Culler, V. H. (Inventor)

    1976-01-01

    A miniature transducer for measuring changes of thickness of the myocardium is described. The device is easily implantable without traumatizing the subject, without affecting the normal muscle behavior, and is removable and implantable at a different muscle location. Operating features of the device are described.

  18. Fluid-structure interaction in abdominal aortic aneurysms: effects of asymmetry and wall thickness

    PubMed Central

    Scotti, Christine M; Shkolnik, Alexander D; Muluk, Satish C; Finol, Ender A

    2005-01-01

    Background Abdominal aortic aneurysm (AAA) is a prevalent disease which is of significant concern because of the morbidity associated with the continuing expansion of the abdominal aorta and its ultimate rupture. The transient interaction between blood flow and the wall contributes to wall stress which, if it exceeds the failure strength of the dilated arterial wall, will lead to aneurysm rupture. Utilizing a computational approach, the biomechanical environment of virtual AAAs can be evaluated to study the affects of asymmetry and wall thickness on this stress, two parameters that contribute to increased risk of aneurysm rupture. Methods Ten virtual aneurysm models were created with five different asymmetry parameters ranging from β = 0.2 to 1.0 and either a uniform or variable wall thickness to study the flow and wall dynamics by means of fully coupled fluid-structure interaction (FSI) analyses. The AAA wall was designed to have a (i) uniform 1.5 mm thickness or (ii) variable thickness ranging from 0.5 – 1.5 mm extruded normally from the boundary surface of the lumen. These models were meshed with linear hexahedral elements, imported into a commercial finite element code and analyzed under transient flow conditions. The method proposed was then compared with traditional computational solid stress techniques on the basis of peak wall stress predictions and cost of computational effort. Results The results provide quantitative predictions of flow patterns and wall mechanics as well as the effects of aneurysm asymmetry and wall thickness heterogeneity on the estimation of peak wall stress. These parameters affect the magnitude and distribution of Von Mises stresses; varying wall thickness increases the maximum Von Mises stress by 4 times its uniform thickness counterpart. A pre-peak systole retrograde flow was observed in the AAA sac for all models, which is due to the elastic energy stored in the compliant arterial wall and the expansion force of the artery

  19. Evaluation of Tube Wall Thickness of Feed Water Heater

    NASA Astrophysics Data System (ADS)

    Uchikura, Takahisa; Morisaki, Koichi; Hamada, Seiichi

    With regard to the high pressure (HP) feed water heater of thermal power plant at Tokyo Electric Power Company (TEPCO) sites, inspection of feed water (FW) tubes wall thickness are conducted whenever required such that frequent tube leak occurs. As a standard inspection methodology, FW heater is disassembled during planned outage, tube wall thickness is measured by the ultrasonic pulse techique (UT), then plugs are installed at the both ends of FW tube if its measured wall thickness is found below calculated threshold. However, the root causes of wall thinning of FW tube are various such as erosion and corrosion, based on wall thinning condition, the above threshold is not applied but utilizing the other technically well-grounded evaluation method is sometimes more rational. Therefore, TEPCO classified wall-thinning condition based on inspection data and established technically well-grounded and rational evaluation methodologies of FW tube wall thickness to suite each wall thinning condition. Moreover, with recent improvement of inspection technique, technology enabled faster, larger amount, and more accurate data acquisition, TEPCO has developed the systematized evaluation methodology that can transact data acquisition and evaluation simultaneously. This article introduces the logic of evaluation methods and examined algorithms to make them systematized.

  20. Bladder wall thickness mapping for magnetic resonance cystography.

    PubMed

    Zhao, Yang; Liang, Zhengrong; Zhu, Hongbin; Han, Hao; Duan, Chaijie; Yan, Zengmin; Lu, Hongbing; Gu, Xianfeng

    2013-08-07

    Clinical studies have shown evidence that the bladder wall thickness is an effective biomarker for bladder abnormalities. Clinical optical cystoscopy, the current gold standard, cannot show the wall thickness. The use of ultrasound by experts may generate some local thickness information, but the information is limited in field-of-view and is user dependent. Recent advances in magnetic resonance (MR) imaging technologies lead MR-based virtual cystoscopy or MR cystography toward a potential alternative to map the wall thickness for the entire bladder. From a high-resolution structural MR volumetric image of the abdomen, a reasonable segmentation of the inner and outer borders of the bladder wall can be achievable. Starting from here, this paper reviews the limitation of a previous distance field-based approach of measuring the thickness between the two borders and then provides a solution to overcome the limitation by an electric field-based strategy. In addition, this paper further investigates a surface-fitting strategy to minimize the discretization errors on the voxel-like borders and facilitate the thickness mapping on the three-dimensional patient-specific bladder model. The presented thickness calculation and mapping were tested on both phantom and human subject datasets. The results are preliminary but very promising with a noticeable improvement over the previous distance field-based approach.

  1. Bladder wall thickness mapping for magnetic resonance cystography

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Liang, Zhengrong; Zhu, Hongbin; Han, Hao; Duan, Chaijie; Yan, Zengmin; Lu, Hongbing; Gu, Xianfeng

    2013-08-01

    Clinical studies have shown evidence that the bladder wall thickness is an effective biomarker for bladder abnormalities. Clinical optical cystoscopy, the current gold standard, cannot show the wall thickness. The use of ultrasound by experts may generate some local thickness information, but the information is limited in field-of-view and is user dependent. Recent advances in magnetic resonance (MR) imaging technologies lead MR-based virtual cystoscopy or MR cystography toward a potential alternative to map the wall thickness for the entire bladder. From a high-resolution structural MR volumetric image of the abdomen, a reasonable segmentation of the inner and outer borders of the bladder wall can be achievable. Starting from here, this paper reviews the limitation of a previous distance field-based approach of measuring the thickness between the two borders and then provides a solution to overcome the limitation by an electric field-based strategy. In addition, this paper further investigates a surface-fitting strategy to minimize the discretization errors on the voxel-like borders and facilitate the thickness mapping on the three-dimensional patient-specific bladder model. The presented thickness calculation and mapping were tested on both phantom and human subject datasets. The results are preliminary but very promising with a noticeable improvement over the previous distance field-based approach.

  2. The logic behind thick, liquid-walled, fusion concepts

    SciTech Connect

    Moir, R.W.

    1994-04-15

    It may be possible to surround the region where fusion reactions are taking place with a neutronically thick liquid blanket which has penetrations that allow only a few tenths of a percent of the neutrons to leak out. Even these neutrons can be attenuated by adding an accurately placed liquid or solid near the target to shadow-shield the beam ports from line-of-sight neutrons. The logic of such designs are discussed and their evolution is described with examples applied to both magnetic and inertial fusion (HYLIFE-II). These designs with liquid protection are self healing when exposed to pulsed loading and have a number of advantages-over the usual designs with solid first walls. For example, the liquid-protected solid components will last the life of the plant, and therefore the capacity factor is estimated to be approximately 10% higher than for the non-liquid-walled blankets, because no blanket replacement shutdowns are required. The component replacement, operations, and maintenance costs might be half the usual value because no blanket change-out costs or accompanying facilities are required. These combined savings might lower the cost of electricity by 20%. Nuclear-grade construction should not be needed, largely because the liquid attenuates neutrons and results in less activation of materials. Upon decommissioning, the reactor materials should qualify for disposal by shallow burial even when constructed of ordinary 304 stainless steel. The need for a high-intensity 14-MeV neutron test facility to develop first-wall materials is avoided or greatly reduced, saving billions of development dollars. Flowing molten Li, the molten salt Flibe (Li{sub 2}BeF{sub 4}), and molten Li{sub l7}Pb{sub 83} have been considered. An advantage of molten salt is that it will not burn and has a low tritium solubility and therefore low tritium inventory.

  3. Absolute neutron dosimetry: Effects of ionization chamber wall thickness

    SciTech Connect

    Ten Haken, R.K.; Awschalom, M.; Rosenberg, I.

    1985-01-01

    To assess the effect of ionization chamber wall thickness on absolute neutron absorbed dose determinations, measurements were made of the charge collected by an A-150 tissue-equivalent plastic ionization chamber irradiated by a p(66)Be(49) neutron therapy beam as a function of chamber wall thickness both in air and in four different media: tissue-equivalent solution, water, motor oil, and glycerin. Wall thicknesses ranged from 1 to 31 mm, where isolation of the chamber gas volume from protons originating outside the chamber wall was assured. The in-air measurements compare favorably with earlier buildup measurements performed with an A-150 extrapolation chamber in an A-150 phantom. The in-phantom results may be explained if the effect of charged particles reaching the gas volume from the medium and the wall as well as the differences in neutron attenuation by the wall and the medium displaced by the wall are taken into account. The errors in absolute absorbed dose determination caused by ignoring the above processes are assessed.

  4. Development of an in vivo tissue-engineered vascular graft with designed wall thickness (biotube type C) based on a novel caged mold.

    PubMed

    Furukoshi, Maya; Moriwaki, Takeshi; Nakayama, Yasuhide

    2016-03-01

    Small-diameter biotube vascular grafts developed by in-body tissue architecture had high patency at implantation into rabbit carotid arteries or rat abdominal aortas. However, the thin walls (34 ± 14 μm) of the original biotubes made their implantation difficult into areas with low blood flow volumes or low blood pressure due to insufficient mechanical strength to maintain luminal shape. In this study, caged molds with several windows were designed to prepare more robust biotubes. The molds were assembled with silicone tubes (external diameter 2 mm) and cylindrical covers (outer diameter 7 mm) with 12 linear windows (1 × 9 mm). After the molds were embedded into beagle dorsal subcutaneous pouches for 4 weeks, type C (cage) biotubes were obtained by completely extracting the surrounding connective tissues from the molds and removing the molds. The biotube walls (778 ± 31 μm) were formed at the aperture (width 1 mm) between the silicone rods and the covers by connective cell migration through the windows of the covers. Excellent mechanical properties (external pressure resistance, approximately 4 times higher than beagle native femoral arteries; burst strength, approximately 2 times higher than original biotubes) were obtained. In the acute phase of implantation of the biotubes into beagle femoral arteries, perfect patency was obtained with little stenosis and no aneurysmal dilation. The type C biotubes may be useful for implantation into peripheral arteries or veins in addition to aortas.

  5. Steel shear walls, behavior, modeling and design

    SciTech Connect

    Astaneh-Asl, Abolhassan

    2008-07-08

    In recent years steel shear walls have become one of the more efficient lateral load resisting systems in tall buildings. The basic steel shear wall system consists of a steel plate welded to boundary steel columns and boundary steel beams. In some cases the boundary columns have been concrete-filled steel tubes. Seismic behavior of steel shear wall systems during actual earthquakes and based on laboratory cyclic tests indicates that the systems are quite ductile and can be designed in an economical way to have sufficient stiffness, strength, ductility and energy dissipation capacity to resist seismic effects of strong earthquakes. This paper, after summarizing the past research, presents the results of two tests of an innovative steel shear wall system where the boundary elements are concrete-filled tubes. Then, a review of currently available analytical models of steel shear walls is provided with a discussion of capabilities and limitations of each model. We have observed that the tension only 'strip model', forming the basis of the current AISC seismic design provisions for steel shear walls, is not capable of predicting the behavior of steel shear walls with length-to-thickness ratio less than about 600 which is the range most common in buildings. The main reasons for such shortcomings of the AISC seismic design provisions for steel shear walls is that it ignores the compression field in the shear walls, which can be significant in typical shear walls. The AISC method also is not capable of incorporating stresses in the shear wall due to overturning moments. A more rational seismic design procedure for design of shear walls proposed in 2000 by the author is summarized in the paper. The design method, based on procedures used for design of steel plate girders, takes into account both tension and compression stress fields and is applicable to all values of length-to-thickness ratios of steel shear walls. The method is also capable of including the effect of

  6. Gear-shift lever having variable thickness walls

    SciTech Connect

    Tanaka, T.

    1988-01-03

    A one-piece elongated tubular transmission gear shift lever, is described comprising a tubular connector part at a first end of the gear shift lever, whereby the tubular connector part is adapted to be secured to a pivot means; a spherical part extending from the connector part, the connector part and the spherical part having a first wall thickness; a cylindrical part extending from the spherical part in a direction opposite the tubular connector part, the cylindrical part having a second wall thickness less than the first wall thickness; a tapered part extending from the cylindrical part; and a threaded part extending from the tapered part, the threaded part formed at a second end of the gear shift lever opposite the first end, whereby a gear shift knob may be attached.

  7. Evaluation of thick wall wave guide element

    NASA Technical Reports Server (NTRS)

    Nalos, E. J.

    1980-01-01

    The SPS transmitting array requires an architecture which will provide a low weight, high efficiency and high structural rigidity. As noted above, waveguide slot arrays constitute the most desirable option. Consequently, such an array has been chosen for the SPS. Waveguide slot arrays offer high efficiency, uniform illumination, are are fairly lighweight. Bandwidths of such arrays are narrow, typically 1/2-2%. Although this does not directly impact the SPS, which transmits power at a single frequency of 2.45 GHz, the narrow bandwidth does constrain the thermal and mechanical tolerances of the antenna. The purpose of this program is to better define the electronic aspects of an SPS specific waveguide slot array. The specific aims of the program are as follows: (1) To build a full-scale half-module, 10 stick, array, the design parameters for which are to be determined by analytical considerations tempered by experimental data on a single slotted radiating stick, (2) To experimentally evaluate the completed array with respect to antenna pattern, impedance and return loss, and (3) To measure swept transmission amplitude and phase to provide a data base for design of a receiving antenna.

  8. Evaluation of scoring accuracy for airway wall thickness

    NASA Astrophysics Data System (ADS)

    Odry, Benjamin L.; Kiraly, Atilla P.; Novak, Carol L.; Naidich, David P.; Ko, Jane P.; Godoy, Myrna C. B.

    2009-02-01

    Bronchial wall thickening is commonly observed in airway diseases. One method often used to quantitatively evaluate wall thickening in CT images is to estimate the ratio of the bronchial wall to the accompanying artery, or BWA ratio, and then assign a severity score based on the ratio. Assessment by visual inspection is unfortunately limited to airways perpendicular or parallel to the scanning plane. With high-resolution images from multi-detector CT scanners, it becomes possible to assess airways in any orientation. We selected CT scans from 20 patients with mild to severe COPD. A computer system automatically segmented each bronchial tree and measured the bronchial wall thicknesses. Next, neighboring arteries were detected and measured to determine BWA ratios. A score characterizing the extent and severity of wall thickening within each lobe was computed according to recommendations by Sheehan et al [1]. Two experienced radiologists independently scored wall thickening using visual assessment. Spearman's rank correlation showed a non-significant negative correlation (r=-0.1) between the computer and the reader average (p=0.4), while the correlation between readers was significant at r=0.65 (p=0.001). We subsequently identified 24 lobes with high discrepancies between visual and automated scoring. The readers re-examined those lobes and measured wall thickness using electronic calipers on perpendicular cross sections, rather than visual assessment. Using this more objective standard of wall thickness, the reader estimates of wall thickening increased to reach a significant positive correlation with automated scoring of r=0.65 (p=0.001). These results indicate that subjectivity is an important problem with visual evaluation, and that visual inspection may frequently underestimate disease extent and severity. Given that a manual evaluation of all airways is infeasible in routine clinical practice, we argue that automated methods should be developed and utilized.

  9. Thick-walled carbon composite multifunctional structures

    NASA Astrophysics Data System (ADS)

    Haake, John M.; Jacobs, Jack H.; McIlroy, Bruce E.

    1997-06-01

    Satellite programs are moving in the direction of smaller and lighter structures. Technological advances have permitted more sophisticated equipment to be consolidated into compact spaces. Micro-satellites, between 10 and 100 kg, will incorporate micro-electric devices into the lay-up of the satellite structure. These structures will be designed to carry load, provide thermal control, enhance damping, and include integrated passive electronics. These multifunctional structures offer lighter weight, reduced volume, and a 'smarter' overall package for incorporation of sensors, electronics, fiber optics, powered appendages or active components. McDonnell Douglas Corporation (MDC) has applied technology from the synthesis and processing of intelligent cost effective structures (SPICES) and independent research and development (IRAD) programs to the modular instrument support system (MISS) for multifunctional space structures and micro-satellites. The SPICES program was funded by the Defense Advanced Research Projects Agency (DARPA) to develop affordable manufacturing processes for smart materials to be used in vibration control, and the MISS program was funded by NASA-Langley. The MISS program was conceived to develop concepts and techniques to make connections between different multifunctional structures. MDA fabricated a trapezoidal carbon composite structure out of IM7/977-3 tape prepreg. Flex circuits, thermal and optical conduits were embedded to realize a utility modular connector. These provide electrical, thermal, optical and mechanical connections between micro- satellite components. A quick disconnect mount was also developed to accommodate a variety of devices such as solar arrays, power sources, thermal transfer and vibration control modules.

  10. Stability of resistive wall modes with plasma rotation and thick wall in ITER scenario

    NASA Astrophysics Data System (ADS)

    Zheng, L. J.; Kotschenreuther, M.; Chu, M.; Chance, M.; Turnbull, A.

    2004-11-01

    The rotation effect on resistive wall modes (RWMs) is examined for realistically shaped, high-beta tokamak equilibria, including reactor relevant cases with low mach number M and realistic thick walls. For low M, Stabilization of RWMs arises from unusually thin inertial layers. The investigation employs the newly developed adaptive eigenvalue code (AEGIS: Adaptive EiGenfunction Independent Solution), which describes both low and high n modes and is in good agreement with GATO in the benchmark studies. AEGIS is unique in using adaptive methods to resolve such inertial layers with low mach number rotation. This feature is even more desirable for transport barrier cases. Additionally, ITER and reactors have thick conducting walls ( ˜.5-1 m) which are not well modeled as a thin shell. Such thick walls are considered here, including semi-analytical approximations to account for the toroidally segmented nature of real walls.

  11. Combined Visualization of Wall Thickness and Wall Shear Stress for the Evaluation of Aneurysms.

    PubMed

    Glaßer, Sylvia; Lawonn, Kai; Hoffmann, Thomas; Skalej, Martin; Preim, Bernhard

    2014-12-01

    For an individual rupture risk assessment of aneurysms, the aneurysm's wall morphology and hemodynamics provide valuable information. Hemodynamic information is usually extracted via computational fluid dynamic (CFD) simulation on a previously extracted 3D aneurysm surface mesh or directly measured with 4D phase-contrast magnetic resonance imaging. In contrast, a noninvasive imaging technique that depicts the aneurysm wall in vivo is still not available. Our approach comprises an experiment, where intravascular ultrasound (IVUS) is employed to probe a dissected saccular aneurysm phantom, which we modeled from a porcine kidney artery. Then, we extracted a 3D surface mesh to gain the vessel wall thickness and hemodynamic information from a CFD simulation. Building on this, we developed a framework that depicts the inner and outer aneurysm wall with dedicated information about local thickness via distance ribbons. For both walls, a shading is adapted such that the inner wall as well as its distance to the outer wall is always perceivable. The exploration of the wall is further improved by combining it with hemodynamic information from the CFD simulation. Hence, the visual analysis comprises a brushing and linking concept for individual highlighting of pathologic areas. Also, a surface clustering is integrated to provide an automatic division of different aneurysm parts combined with a risk score depending on wall thickness and hemodynamic information. In general, our approach can be employed for vessel visualization purposes where an inner and outer wall has to be adequately represented.

  12. Development of remaining wall thickness measurement system for boiler wall tube using gamma scattering technique

    NASA Astrophysics Data System (ADS)

    Durongsak, K.; Yenjai, C.; Rassame, S.

    2017-06-01

    In this study, the General Monte Carlo N-Particle version 5 (MCNP5) simulation of the measuring system for the remaining thickness of the wall tube using gamma scattering technique is performed to investigate the applicability of this technique and to find the optimum geometrical setup for the experimental setup. The numerical results show that the optimal geometry condition to provide the highest ratio between the gamma flux changes per thickness variation, namely, the measurement sensitivity, is the alignment of the source incidence angle of 30 degree and detector scattering angle of 30 degrees. Sequentially, the preliminary experiment of thickness measurement system for the tube using the gamma scattering technique is conducted based on the selected geometrical test setup by the simulation. It is found that the experimental results have generally a good agreement with the calculated results. Conclusively, it is suggested that the gamma scattering technique has a potential method to measure the remaining wall thickness in the boiler wall tube.

  13. Thick domain walls in AdS black hole spacetimes

    SciTech Connect

    Moderski, Rafal; Rogatko, Marek

    2006-08-15

    Equations of motion for a real self-gravitating scalar field in the background of a black hole with negative cosmological constant were solved numerically. We obtain a sequence of static axisymmetric solutions representing thick domain wall cosmological black hole systems, depending on the mass of black hole, cosmological parameter and the parameter binding black hole mass with the width of the domain wall. For the case of extremal cosmological black hole the expulsion of scalar field from the black hole strongly depends on it.

  14. Noninvasive Stiffness Sensing of Ventricular Wall Based on a Thick-walled Cylinder Model

    NASA Astrophysics Data System (ADS)

    Higashimori, Mitsuru; Ojio, Takeshi; Takeda, Yasuharu; Sakata, Yasushi; Yamamoto, Kazuhiro; Kaneko, Makoto

    This paper discusses a concept of a noninvasive sensing method that can estimate a left ventricular wall stiffness towards a medical diagnosis. Focusing on not only the strain of ventricular wall but also the displacements of epicardium during diastole of heart beat, we propose an index of ventricular wall stiffness based on a thick-walled cylinder model. Applying the proposed method to the echocardiography, we show statistical results where normal and HFpEF (Heart Failure with preserved Ejection Fraction) can be separated towards a medical diagnosis.

  15. The role of myocardial wall thickness in atrial arrhythmogenesis.

    PubMed

    Whitaker, John; Rajani, Ronak; Chubb, Henry; Gabrawi, Mark; Varela, Marta; Wright, Matthew; Niederer, Steven; O'Neill, Mark D

    2016-12-01

    Changes in the structure and electrical behaviour of the left atrium are known to occur with conditions that predispose to atrial fibrillation (AF) and in response to prolonged periods of AF. We review the evidence that changes in myocardial thickness in the left atrium are an important part of this pathological remodelling process. Autopsy studies have demonstrated changes in the thickness of the atrial wall between patients with different clinical histories. Comparison of the reported tissue dimensions from pathological studies provides an indication of normal ranges for atrial wall thickness. Imaging studies, most commonly done using cardiac computed tomography, have demonstrated that these changes may be identified non-invasively. Experimental evidence using isolated tissue preparations, animal models of AF, and computer simulations proves that the three-dimensional tissue structure will be an important determinant of the electrical behaviour of atrial tissue. Accurately identifying the thickness of the atrial may have an important role in the non-invasive assessment of atrial structure. In combination with atrial tissue characterization, a comprehensive assessment of the atrial dimensions may allow prediction of atrial electrophysiological behaviour and in the future, guide radiofrequency delivery in regions based on their tissue thickness.

  16. Designing a Sound Reducing Wall

    ERIC Educational Resources Information Center

    Erk, Kendra; Lumkes, John; Shambach, Jill; Braile, Larry; Brickler, Anne; Matthys, Anna

    2015-01-01

    Acoustical engineers use their knowledge of sound to design quiet environments (e.g., classrooms and libraries) as well as to design environments that are supposed to be loud (e.g., concert halls and football stadiums). They also design sound barriers, such as the walls along busy roadways that decrease the traffic noise heard by people in…

  17. Designing a Sound Reducing Wall

    ERIC Educational Resources Information Center

    Erk, Kendra; Lumkes, John; Shambach, Jill; Braile, Larry; Brickler, Anne; Matthys, Anna

    2015-01-01

    Acoustical engineers use their knowledge of sound to design quiet environments (e.g., classrooms and libraries) as well as to design environments that are supposed to be loud (e.g., concert halls and football stadiums). They also design sound barriers, such as the walls along busy roadways that decrease the traffic noise heard by people in…

  18. Chest wall thickness measurements for enriched uranium: An alternative approach

    SciTech Connect

    Kramer, G.H.; Puscalau, M.

    1994-05-01

    Human Monitoring Laboratory has developed a technique to determine the chest wall thickness of an individual using information from the spectrum produced by internally deposited radionuclides. The technique has been investigated both theoretically and practically using phoswich detectors and the Lawrence Livermore Torso Phantom. The phantom was used with lung sets containing homogeneously distributed 93% enriched uranium, 20% enriched uranium, natural uranium, and {sup 241}Am. It was found that a 3-cm chest wall thickness can be estimated to within 9% when measuring 93% enriched uranium. The technique does not work for the latter two radionuclides because of an insufficient separation in the photon energies and poor resolution of the phoswich detectors. The technique is only of value for activity levels limit. 5 refs., 3 figs., 1 tab.

  19. Evaluation of UT Wall Thickness Measurements and Measurement Methodology

    SciTech Connect

    Weier, Dennis R.; Pardini, Allan F.

    2007-10-01

    CH2M HILL has requested that PNNL examine the ultrasonic methodology utilized in the inspection of the Hanford double shell waste tanks. Specifically, PNNL is to evaluate the UT process variability and capability to detect changes in wall thickness and to document the UT operator's techniques and methodology in the determination of the reported minimum and average UT data and how it compares to the raw (unanalyzed) UT data.

  20. Ultrasound settings significantly alter arterial lumen and wall thickness measurements

    PubMed Central

    Potter, Kathleen; Reed, Christopher J; Green, Daniel J; Hankey, Graeme J; Arnolda, Leonard F

    2008-01-01

    Background Flow-mediated dilation (FMD) and carotid intima-medial thickness (CIMT), measured by ultrasound, are widely used to test the efficacy of cardioprotective interventions. Although assessment methods vary, automated edge-detecting image analysis software is routinely used to measure changes in FMD and CIMT. We aimed to quantify the effect that commonly adjusted ultrasound settings have on arterial lumen and wall thickness measurements made with CIMT measurement software. Methods We constructed phantom arteries from a tissue-mimicking agar compound and scanned them in a water bath with a 10 MHz multi-frequency linear-array probe attached to a high-resolution ultrasound machine. B-mode images of the phantoms were recorded with dynamic range (DR) and gain set at five decibel (dB) increments from 40 dB to 60 dB and -10 dB to +10 dB respectively. Lumen diameter and wall-thickness were measured off-line using CIMT measurement software. Results Lumen measurements: there was a strong linear relationship between DR and gain and measured lumen diameter. For a given gain level, a 5 dB increase in DR reduced the measured lumen diameter by 0.02 ± 0.004 mm (p < 0.001). For a given DR level, a 5 dB increase in gain reduced measured lumen diameter by 0.04 ± 0.004 mm (p < 0.001). A 5 mm increase in distance between the ultrasound probe and the artery reduced measured lumen diameter by 0.04 ± 0.03 mm (p < 0.001) CIMT measurements: For a fixed gain level, a 5 dB increase in DR increased measured wall thickness by 0.003 ± 0.002 mm (p < 0.001). The effects of increasing gain were not consistent and appeared to vary depending on the distance between the artery and the ultrasound probe and the thickness of the artery wall. Conclusion DR, gain and probe distance significantly alter lumen diameter and CIMT measurements made using image analysis software. When CIMT and FMD are used to test the efficacy of cardioprotective interventions, the DR, gain and probe position used to

  1. Enhancing cell-free layer thickness by bypass channels in a wall.

    PubMed

    Saadatmand, M; Shimogonya, Y; Yamaguchi, T; Ishikawa, T

    2016-07-26

    When blood flows near a wall, red blood cells (RBCs) drift away from the wall and a cell-free layer (CFL) is formed adjacent to the wall. Controlling the CFL thickness is important for preventing adhesion of cells in the design of biomedical devices. In this study, a novel wall configuration with stenoses and bypass channels is proposed to increase the CFL thickness. We found that the presence of bypass channels modified the spatial distribution of cells and substantially increased the CFL downstream of the stenosis. A single-bypass geometry with 5% hematocrit (Hct) blood flow showed a 1.7μm increase in CFL thickness compared to without the bypass. In the case of three bypass channels, a 3μm increase in CFL thickness was observed. The CFL enhancement was observed up to 10% Hct, but no significant enhancement of CFL was indicated for 20% Hct blood flow. The mechanism of the CFL enhancement was investigated using a numerical simulation of the flow field. The results showed that the distance between each streamline and the corner of the stenosis compared with size of RBC was important parameter in regulating CFL thickness. These results show the potential of the proposed mechanism to prevent adhesion of cells to biomedical devices.

  2. Terahertz inline wall thickness monitoring system for plastic pipe extrusion

    NASA Astrophysics Data System (ADS)

    Hauck, J.; Stich, D.; Heidemeyer, P.; Bastian, M.; Hochrein, T.

    2014-05-01

    Conventional and commercially available inline wall thickness monitoring systems for pipe extrusion are usually based on ultrasonic or x-ray technology. Disadvantages of ultrasonic systems are the usual need of water as a coupling media and the high damping in thick walled or foamed pipes. For x-ray systems special safety requirements have to be taken into account because of the ionizing radiation. The terahertz (THz) technology offers a novel approach to solve these problems. THz waves have many properties which are suitable for the non-destructive testing of plastics. The absorption of electrical isolators is typically very low and the radiation is non-ionizing in comparison to x-rays. Through the electromagnetic origin of the THz waves they can be used for contact free measurements. Foams show a much lower absorption in contrast to acoustic waves. The developed system uses THz pulses which are generated by stimulating photoconductive switches with femtosecond laser pulses. The time of flight of THz pulses can be determined with a resolution in the magnitude of several ten femtoseconds. Hence the thickness of an object like plastic pipes can be determined with a high accuracy by measuring the time delay between two reflections on materials interfaces e.g. at the pipe's inner and outer surface, similar to the ultrasonic technique. Knowing the refractive index of the sample the absolute layer thickness from the transit time difference can be calculated easily. This method in principle also allows the measurement of multilayer systems and the characterization of foamed pipes.

  3. Terahertz inline wall thickness monitoring system for plastic pipe extrusion

    SciTech Connect

    Hauck, J. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de Stich, D. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de Heidemeyer, P. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de Bastian, M. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de Hochrein, T. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de

    2014-05-15

    Conventional and commercially available inline wall thickness monitoring systems for pipe extrusion are usually based on ultrasonic or x-ray technology. Disadvantages of ultrasonic systems are the usual need of water as a coupling media and the high damping in thick walled or foamed pipes. For x-ray systems special safety requirements have to be taken into account because of the ionizing radiation. The terahertz (THz) technology offers a novel approach to solve these problems. THz waves have many properties which are suitable for the non-destructive testing of plastics. The absorption of electrical isolators is typically very low and the radiation is non-ionizing in comparison to x-rays. Through the electromagnetic origin of the THz waves they can be used for contact free measurements. Foams show a much lower absorption in contrast to acoustic waves. The developed system uses THz pulses which are generated by stimulating photoconductive switches with femtosecond laser pulses. The time of flight of THz pulses can be determined with a resolution in the magnitude of several ten femtoseconds. Hence the thickness of an object like plastic pipes can be determined with a high accuracy by measuring the time delay between two reflections on materials interfaces e.g. at the pipe's inner and outer surface, similar to the ultrasonic technique. Knowing the refractive index of the sample the absolute layer thickness from the transit time difference can be calculated easily. This method in principle also allows the measurement of multilayer systems and the characterization of foamed pipes.

  4. 49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Nominal wall thickness (t) for steel pipe. (a) If the nominal wall thickness for steel pipe is not...

  5. 49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Nominal wall thickness (t) for steel pipe. (a) If the nominal wall thickness for steel pipe is not...

  6. 49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Nominal wall thickness (t) for steel pipe. (a) If the nominal wall thickness for steel pipe is not...

  7. 49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Nominal wall thickness (t) for steel pipe. (a) If the nominal wall thickness for steel pipe is not...

  8. 49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Nominal wall thickness (t) for steel pipe. (a) If the nominal wall thickness for steel pipe is not...

  9. A More Accurate Solution to the Elastic-Plastic Problem of Pressurized Thick-Walled Cylinders.

    DTIC Science & Technology

    1985-02-01

    PLASTIC PROBLEM OF PRESSURIZED THICK-WALLED CYLINDERS Wt) .0 PETER C. T...34ACT’rowim- -noes Sei Nomee..w snidswitby block numbr) A new method has been developed for solving the partially plastic problems of * thick-walled...34. -.........,..- - -. .. . ..... ,.... . ..... .*...**..*.... ... INTRODUCTION The partially plastic problem of pressurized thick-walled cylinder is of practical importance to pressure vessels and the

  10. [Influence of wall thickness on the stress distribution within transtibial monolimb].

    PubMed

    Liu, Zhan; Fan, Yubo; Zhang, Ming; Jiang, Wentao; Pu, Fang; Chen, Junkai

    2004-08-01

    Monolimb is a new type of lower-limb prostheses made of macromolecule polymer, in which the socket and prosthetic shank are integrative. Compared with traditional prosthesis, monolimb is more economical, good-looking and portable, so it indicates a possible direction in the future. Biomechanical research on trans-tibial monolimb is necessary and helpful just like traditional prosthesis. In this article, a 3D FE model based on real geometry shape of an endoskeletal trans-tibial monolimb is established. Keeping the same geometrical shape, three 3D FE models of transtibial monolimbs with different wall thickness are established. The influence of wall thickness on the stress distribution is analyzed under the load corresponding to the subphase of stance of Heel Off. The results indicate that stress within transtibial monolimb and pressure on the surface of soft tissue could be decreased with wall thickness of transtibial monolimb increased. This study will be helpful for the standard of wall thickness in designing transtibial monolimb.

  11. Injection-moulded models of major and minor arteries: the variability of model wall thickness owing to casting technique.

    PubMed

    O'Brien, T; Morris, L; O'Donnell, M; Walsh, M; McGloughlin, T

    2005-09-01

    Cardiovascular disease of major and minor arteries is a common cause of death in Western society. The wall mechanics and haemodynamics within the arteries are considered to be important factors in the disease formation process. This paper is concerned with the development of an efficient computer-integrated technique to manufacture idealized and realistic models of diseased major and minor arteries from radiological images and to address the issue of model wall thickness variability. Variations in wall thickness from the original computer models to the final castings are quantified using a CCD camera. The results found that wall thickness variation from the major and minor idealized artery models to design specification were insignificant, up to a maximum of 16 per cent. In realistic models, however, differences were up to 23 per cent in the major arterial models and 58 per cent in the minor arterial models, but the wall thickness variability remained within the limits of previously reported wall thickness results. It is concluded that the described injection moulding procedure yields idealized and realistic castings suitable for use in experimental investigations, with idealized models giving better agreement with design. Wall thickness is variable and should be assessed after the models are manufactured.

  12. Stress intensity factors in a reinforced thick-walled cylinder

    NASA Technical Reports Server (NTRS)

    Tang, R.; Erdogan, F.

    1984-01-01

    An elastic thick-walled cylinder containing a radial crack is considered. It is assumed that the cylinder is reinforced by an elastic membrane on its inner surface. The model is intended to simulate pressure vessels with cladding. The formulation of the problem is reduced to a singular integral equation. Various special cases including that of a crack terminating at the cylinder-reinforcement interface are investigated and numerical examples are given. Results indicate that in the case of the crack touching the interface the crack surface displacement derivative is finite and consequently the stress state around the corresponding crack tip is bounded; and generally, for realistic values of the stiffness parameter, the effect of the reinforcement is not very significant.

  13. Effect of wall thickness on measurement of dose for high energy neutrons.

    PubMed

    Perez-Nunez, Delia; Braby, Leslie A

    2010-01-01

    Neutrons produced from the interaction between galactic cosmic rays and spacecraft materials are responsible for a very important portion of the dose received by astronauts. The neutron energy spectrum depends on the incident charged particle spectrum and the scattering environment but generally extends to beyond 100 MeV. Tissue-equivalent proportional counters (TEPC) are used to measure the dose during the space mission, but their weight and size are very important factors for their design and construction. To achieve ideal neutron dosimetry, the wall thickness should be at least the range of a proton having the maximum energy of the neutrons to be monitored. This proton range is 0.1 cm for 10 MeV neutrons and 7.6 cm for 100 MeV neutrons. A 7.6 cm wall thickness TEPC would provide charged particle equilibrium (CPE) for neutrons up to 100 MeV, but for space applications it would not be reasonable in terms of weight and size. In order to estimate the errors in measured dose due to absence of CPE, MCNPX simulations of energy deposited by 10 MeV and 100 MeV neutrons in sites with wall thickness between 0.1 cm and 8.5 cm were performed. The results for 100 MeV neutrons show that energy deposition per incident neutron approaches a plateau as the wall thickness approaches 7.6 cm. For the 10 MeV neutrons, energy deposition per incident neutron decreases as the wall thickness increases above 0.1 cm due to attenuation.

  14. Thick Liquid-Walled, Field-Reversed Configuration

    SciTech Connect

    Moir, R W; Bulmer, R H; Gulec, K; Fogarty, P; Nelson, B; Ohnishi, M; Rensink, M; Rognlien, T D; Santarious, J F; Sze, D K

    2000-09-22

    A thick flowing layer of liquid (e.g., flibe--a molten salt, or Sn{sub 80}Li{sub 20}--a liquid metal) protects the structural walls of the field-reversed configuration (FRC) so that they can last the life of the plant even with intense 14 MeV neutron bombardment from the D-T fusion reaction. The surface temperature of the liquid rises as it passes from the inlet nozzles to the exit or receiver nozzles due to absorption of line and bremsstrahlung radiation, and neutrons. The surface temperature can be reduced by enhancement of convection near the surface to transport hot surface liquid into the cooler interior. This surface temperature must be compatible with a practical heat transport and energy recovery system. The evaporative flux from the wall driven by the surface temperature must also result in an acceptable impurity level in the core plasma. The shielding of the core by the edge plasma is modeled with a 2D transport code for the resulting impurity ions; these ions are either swept out to the distant end tanks, or diffuse to the hot plasma core. An auxiliary plasma between the edge plasma and the liquid wall can further attenuate evaporating flux of atoms and molecules by ionization. The current in this auxiliary plasma might serve as the antenna for the current drive method, which produces a rotating magnetic field. Another method of current drive uses small spheromaks injected along the magnetic fields, which additionally provide fueling along with pellet fueling if necessary.

  15. Flow Conditioning Design in Thick Liquid Protection

    SciTech Connect

    Durbin, S.G.; Yoda, M.; Abdel-Khalik, S.I.

    2005-04-15

    The HYLIFE-II conceptual design proposed using arrays of high-speed oscillating and stationary slab jets, or turbulent liquid sheets, to protect the reactor chamber first walls from damaging neutrons, ions and X-rays. Flow conditioning can be used to reduce turbulent fluctuations in these liquid sheets and thereby reduce surface ripple, or free-surface fluctuations, and delay jet breakup. Several flow conditioning configurations are studied experimentally for vertical turbulent sheets of water issuing downwards from nozzles of thickness (small dimension) {delta} = 1 cm into ambient air for Reynolds numbers Re = 5.0 x 10{sup 4} and 1.2 x 10{sup 5}. In particular, the role of one or more fine screens in the flow conditioner was studied. As the flow conditioning element immediately upstream of the nozzle inlet, fine screens have been shown to have a major impact upon the sheet free-surface geometry. Planar laser-induced fluorescence was used to measure the free-surface geometry of the liquid sheet and its fluctuations in the near field at streamwise distances downstream of the nozzle exit x {<=} 25{delta}. Laser-Doppler velocimetry was used to quantify the impact of different conditioning configurations on the cross-stream velocity component and its fluctuations just upstream of the nozzle exit. The results indicate that minor differences in velocity and velocity fluctuations near the nozzle exit can lead to major variations in free-surface geometry, and that free-surface fluctuations are strongly affected by changes in flow conditioner design, even in the near-field region of the flow. A single-screen configuration was shown to produce the smoothest jets at both Reynolds numbers, with fluctuations of 3.3% at Re = 1.2 x 10{sup 5} and x = 25{delta}.

  16. Ultrasonic guided wave tomography for wall thickness mapping in pipes

    NASA Astrophysics Data System (ADS)

    Willey, Carson L.

    Corrosion and erosion damage pose fundamental challenges to operation of oil and gas infrastructure. In order to manage the life of critical assets, plant operators must implement inspection programs aimed at assessing the severity of wall thickness loss (WTL) in pipelines, vessels, and other structures. Maximum defect depth determines the residual life of these structures and therefore represents one of the key parameters for robust damage mitigation strategies. In this context, continuous monitoring with permanently installed sensors has attracted significant interest and currently is the subject of extensive research worldwide. Among the different monitoring approaches being considered, significant promise is offered by the combination of guided ultrasonic wave technology with the principles of model based inversion under the paradigm of what is now referred to as guided wave tomography (GWT). Guided waves are attractive because they propagate inside the wall of a structure over a large distance. This can yield significant advantages over conventional pulse-echo thickness gage sensors that provide insufficient area coverage -- typically limited to the sensor footprint. While significant progress has been made in the application of GWT to plate-like structures, extension of these methods to pipes poses a number of fundamental challenges that have prevented the development of sensitive GWT methods. This thesis focuses on these challenges to address the complex guided wave propagation in pipes and to account for parametric uncertainties that are known to affect model based inversion and which are unavoidable in real field applications. The main contribution of this work is the first demonstration of a sensitive GWT method for accurately mapping the depth of defects in pipes. This is achieved by introducing a novel forward model that can extract information related to damage from the complex waveforms measured by pairs of guided wave transducers mounted on the pipe

  17. Correlation between the bronchial subepithelial layer and whole airway wall thickness in patients with asthma

    PubMed Central

    Kasahara, K; Shiba, K; Ozawa, T; Okuda, K; Adachi, M

    2002-01-01

    Background: The epithelial reticular basement membrane (Rbm) of the airway wall thickens in patients with asthma. However, whether the thickening parallels whole airway wall thickening, which limits airflow, is unknown. The aim of this study was to examine the correlation between the bronchial Rbm thickening and whole airway wall thickening in asthma. In addition, the association of Rbm and whole wall thickening with airflow obstruction was examined. Methods: Forty nine patients with asthma and 18 healthy control subjects took part in the study. The Rbm thickness was measured in bronchial biopsy specimens and whole airway wall thickness was assessed with high resolution computed tomographic (HRCT) scanning after pretreatment with oral steroids for 2 weeks and inhaled ß2 agonist to minimise reversible changes of the airway walls. The percentage airway wall area (WA%; defined as (wall area/total airway area) x 100) and percentage airway wall thickness (WT%; defined as [(ideal outer diameter – ideal luminal diameter)/ideal outer diameter] x 100) were determined from HRCT scans to assess whole airway wall thickness. Spirometric tests were also performed. Results: WA% and WT% were higher in patients with asthma than in healthy subjects. Both WA% and WT% were strongly correlated with Rbm thickness. Moreover, these three indices of airway wall thickness were inversely correlated with the percentage of predicted forced expiratory volume in 1 second in patients with asthma. Conclusions: These findings indicate that Rbm thickening parallels whole airway wall thickening which can cause irreversible airflow obstruction in patients with asthma. PMID:11867829

  18. A pilot study on bladder wall thickness at different filling stages

    NASA Astrophysics Data System (ADS)

    Zhang, Xi; Liu, Yang; Li, Baojuan; Zhang, Guopeng; Liang, Zhengrong; Lu, Hongbing

    2015-03-01

    The ever-growing death rate and the high recurrence of bladder cancer make the early detection and appropriate followup procedure of bladder cancer attract more attention. Compare to optical cystoscopy, image-based studies have revealed its potentials in non-invasive observations of the abnormities of bladder recently, in which MR imaging turns out to be a better choice for bladder evaluation due to its non-ionizing and high contrast between urine and wall tissue. Recent studies indicate that bladder wall thickness tends to be a good indicator for detecting bladder wall abnormalities. However, it is difficult to quantitatively compare wall thickness of the same subject at different filling stages or among different subjects. In order to explore thickness variations at different bladder filling stages, in this study, we preliminarily investigate the relationship between bladder wall thickness and bladder volume based on a MRI database composed of 40 datasets acquired from 10 subjects at different filling stages, using a pipeline for thickness measurement and analysis proposed in our previous work. The Student's t-test indicated that there was no significant different on wall thickness between the male group and the female group. The Pearson correlation analysis result indicated that negative correlation with a correlation coefficient of -0.8517 existed between the wall thickness and bladder volume, and the correlation was significant(p <0.01). The corresponding linear regression equation was then estimated by the unary linear regression. Compared to the absolute value of wall thickness, the z-score of wall thickness would be more appropriate to reflect the thickness variations. For possible abnormality detection of a bladder based on wall thickness, the intra-subject and inter-subject thickness variation should be considered.

  19. Fluid-Structure Simulations of a Ruptured Intracranial Aneurysm: Constant versus Patient-Specific Wall Thickness

    PubMed Central

    Hoffmann, T.; Beuing, O.; Jachau, K.; Thévenin, D.; Janiga, G.; Berg, P.

    2016-01-01

    Computational Fluid Dynamics is intensively used to deepen the understanding of aneurysm growth and rupture in order to support physicians during therapy planning. However, numerous studies considering only the hemodynamics within the vessel lumen found no satisfactory criteria for rupture risk assessment. To improve available simulation models, the rigid vessel wall assumption has been discarded in this work and patient-specific wall thickness is considered within the simulation. For this purpose, a ruptured intracranial aneurysm was prepared ex vivo, followed by the acquisition of local wall thickness using μCT. The segmented inner and outer vessel surfaces served as solid domain for the fluid-structure interaction (FSI) simulation. To compare wall stress distributions within the aneurysm wall and at the rupture site, FSI computations are repeated in a virtual model using a constant wall thickness approach. Although the wall stresses obtained by the two approaches—when averaged over the complete aneurysm sac—are in very good agreement, strong differences occur in their distribution. Accounting for the real wall thickness distribution, the rupture site exhibits much higher stress values compared to the configuration with constant wall thickness. The study reveals the importance of geometry reconstruction and accurate description of wall thickness in FSI simulations. PMID:27721898

  20. Fluid-Structure Simulations of a Ruptured Intracranial Aneurysm: Constant versus Patient-Specific Wall Thickness.

    PubMed

    Voß, S; Glaßer, S; Hoffmann, T; Beuing, O; Weigand, S; Jachau, K; Preim, B; Thévenin, D; Janiga, G; Berg, P

    2016-01-01

    Computational Fluid Dynamics is intensively used to deepen the understanding of aneurysm growth and rupture in order to support physicians during therapy planning. However, numerous studies considering only the hemodynamics within the vessel lumen found no satisfactory criteria for rupture risk assessment. To improve available simulation models, the rigid vessel wall assumption has been discarded in this work and patient-specific wall thickness is considered within the simulation. For this purpose, a ruptured intracranial aneurysm was prepared ex vivo, followed by the acquisition of local wall thickness using μCT. The segmented inner and outer vessel surfaces served as solid domain for the fluid-structure interaction (FSI) simulation. To compare wall stress distributions within the aneurysm wall and at the rupture site, FSI computations are repeated in a virtual model using a constant wall thickness approach. Although the wall stresses obtained by the two approaches-when averaged over the complete aneurysm sac-are in very good agreement, strong differences occur in their distribution. Accounting for the real wall thickness distribution, the rupture site exhibits much higher stress values compared to the configuration with constant wall thickness. The study reveals the importance of geometry reconstruction and accurate description of wall thickness in FSI simulations.

  1. Effects of Antimony and Wall Thickness on Graphite Morphology in Ductile Iron Castings

    NASA Astrophysics Data System (ADS)

    Glavas, Zoran; Strkalj, Anita; Maldini, Kresimir

    2016-08-01

    Effects of Sb additions on the graphite morphology of ductile iron castings in different wall thicknesses (3, 12, 25, 38, 50, 75, and 100 mm) were analyzed in this paper. In the wall thicknesses of 3, 12, and 25 mm, low contents of rare earth (RE) elements showed a beneficial effect on nodule count and nodularity. Nodularity >80 pct and a high nodule count were achieved without the addition of Sb. In the wall thicknesses of 38, 50, 75, and 100 mm, nodularity >80 pct was not achieved without the use of the chill or proper content of Sb. Excess of RE elements was neutralized with the addition of proper amount of Sb to the wall thickness. Addition of 0.01 wt pct Sb (ratio of RE/Sb = 0.34, ratio of RE/SE = 0.105) was sufficient to achieve nodularity >80 pct in the wall thicknesses of 38, 50, 75, and 100 mm.

  2. A More Accurate Solution to the Elastic-Plastic Problem of Pressurized Thick-Walled Cylinders

    DTIC Science & Technology

    1985-02-01

    ACCURATE SOLUTION TO THE ELASTIC- PLASTIC PROBLEM OF PRESSURIZED THICK-WALLED CYLINDERS S. TYPE OF REPORT 4’ PERIOD COVERED Final 8. PERFORMING...o £ ) A MORE ACCURATE SOLUTION TO THE ELASTIC- PLASTIC PROBLEM OF PREr SURIZED THICK-WALLED CYLINDERS < • Peter C. T. Chen U.S. Army Armament...Watervllet, NY 12189 I iJSTRACT. A new method has been developed for solving the partially plastic problems of thlc’ -walled cylinders made of strain

  3. Method of manufacturing hollow members having uniform wall thickness through use of ablation

    DOEpatents

    Anderson, Paul R.; Downs, Raymond L.; Henderson, Timothy M.

    1982-01-01

    A method of manufacturing a hollow structure of uniform wall thickness comprising the steps of selecting or forming a precursor having one wall surface of desired geometry, treating a portion of the precursor consisting of the one wall surface and a uniform depth of material beneath the wall surface to increase resistance to ablation, and then removing by ablation and discarding the remaining or untreated portion of the precursor.

  4. The development and structure of thick-walled, multicellular, aerial spores in Diheterospora chlamydosporia (=Verticillium chlamydosporium).

    PubMed

    Cambell, W P; Griffiths, D A

    1975-07-01

    The aerial, thick-walled spores in Diheterospara chlamydosporia arose as terminal swellings on erect hyphae. Repeated septation of the continuously swelling spore resulted in a multicellular structure. Immediately after the onset of septation secondary wall material was laid down between the two-layered primary wall and the plasmalemma. The presence of secondary wall material indicates that the multicellular spore is a dictyochlamydospore and not an aleuriospore. The relationship between chlamydospores and aleuriospores in other fungi is discussed.

  5. Energy dependent chest wall thickness equations for male lung monitoring with germanium detectors.

    PubMed

    Broggio, D; Lechaftois, X; Abline, O; Fleury, B; Vial, A; Corrèze, P; Franck, D; Merzoug, V

    2014-03-01

    The thickness and fat fraction of the chest wall are important parameters for in vivo lung monitoring. They have been measured from ultrasonic images on 374 male workers of the French nuclear industry using four measurement locations, as dictated by the size and position of the germanium detectors used for monitoring. The plastic muscle equivalent chest wall thickness (PMECWT) and the plastic 50% muscle-50% adipose equivalent chest wall thickness (X5050) have been calculated for each worker at 17, 59.5, and 185.7 keV, respectively. Multi-linear regression models have been tested to predict PMECWT and X5050 as a function of anthropometric measurements. Finally, it was considered whether the average chest wall thickness could be used instead of the material equivalent chest wall thickness. It was found that the mean chest wall thickness was (27 ± 5) mm and the mean fat fraction was (25 ± 8)%. The best and more convenient model for material equivalent chest wall thickness is a linear function of the body mass index. Depending on the energy, the standard errors of estimate for this model range between 3.2-3.4 mm for PMECWT and between 3.2-3.7 mm for X5050. At 59.5 and 185.7 keV, it was determined, to an excellent approximation, that the fat fraction and consideration of an equivalent material are unnecessary, contrary to the case at 17 keV.

  6. The Bulging Behavior of Thick-Walled 6063 Aluminum Alloy Tubes Under Double-Sided Pressures

    NASA Astrophysics Data System (ADS)

    Cui, Xiao-Lei; Wang, Xiao-Song; Yuan, Shi-Jian

    2015-05-01

    To make further exploration on the deformation behavior of tube under double-sided pressures, the thick-walled 6063 aluminum alloy tubes with an outer diameter of 65 mm and an average thickness of 7.86 mm have been used to be bulged under the combined action of internal and external pressures. In the experiment, two ends of the thick-walled tubes were fixed using the tooth and groove match. Three levels of external pressure (0 MPa, 40 MPa, and 80 MPa), in conjunction with the internal pressure, were applied on the tube outside and inside simultaneously. The effect of external pressure on the bulging behavior of the thick-walled tubes, such as the limiting expansion ratio, the bulging zone profile, and the thickness distribution, has been investigated. It is shown that the limiting expansion ratio, the bulging zone profile, and the thickness distribution in the homogeneous bulging area are all insensitive to the external pressure. However, the external pressure can make the thick-walled tube achieve a thinner wall at the fracture area. It reveals that the external pressure can only improve the fracture limit of the thick-walled 6063 tubes, but it has very little effect on their homogeneous bulging behavior. It might be because the external pressure can only increase the magnitude of the hydrostatic pressure for the tube but has no effect on the Lode parameter.

  7. Patient-specific left atrial wall-thickness measurement and visualization for radiofrequency ablation

    NASA Astrophysics Data System (ADS)

    Inoue, Jiro; Skanes, Allan C.; White, James A.; Rajchl, Martin; Drangova, Maria

    2014-03-01

    INTRODUCTION: For radiofrequency (RF) catheter ablation of the left atrium, safe and effective dosing of RF energy requires transmural left atrium ablation without injury to extra-cardiac structures. The thickness of the left atrial wall may be a key parameter in determining the appropriate amount of energy to deliver. While left atrial wall-thickness is known to exhibit inter- and intra-patient variation, this is not taken into account in the current clinical workflow. Our goal is to develop a tool for presenting patient-specific left atrial thickness information to the clinician in order to assist in the determination of the proper RF energy dose. METHODS: We use an interactive segmentation method with manual correction to segment the left atrial blood pool and heart wall from contrast-enhanced cardiac CT images. We then create a mesh from the segmented blood pool and determine the wall thickness, on a per-vertex basis, orthogonal to the mesh surface. The thickness measurement is visualized by assigning colors to the vertices of the blood pool mesh. We applied our method to 5 contrast-enhanced cardiac CT images. RESULTS: Left atrial wall-thickness measurements were generally consistent with published thickness ranges. Variations were found to exist between patients, and between regions within each patient. CONCLUSION: It is possible to visually determine areas of thick vs. thin heart wall with high resolution in a patient-specific manner.

  8. Semiautomatic vessel wall detection and quantification of wall thickness in computed tomography images of human abdominal aortic aneurysms

    SciTech Connect

    Shum, Judy; DiMartino, Elena S.; Goldhammer, Adam; Goldman, Daniel H.; Acker, Leah C.; Patel, Gopal; Ng, Julie H.; Martufi, Giampaolo; Finol, Ender A.

    2010-02-15

    Purpose: Quantitative measurements of wall thickness in human abdominal aortic aneurysms (AAAs) may lead to more accurate methods for the evaluation of their biomechanical environment. Methods: The authors describe an algorithm for estimating wall thickness in AAAs based on intensity histograms and neural networks involving segmentation of contrast enhanced abdominal computed tomography images. The algorithm was applied to ten ruptured and ten unruptured AAA image data sets. Two vascular surgeons manually segmented the lumen, inner wall, and outer wall of each data set and a reference standard was defined as the average of their segmentations. Reproducibility was determined by comparing the reference standard to lumen contours generated automatically by the algorithm and a commercially available software package. Repeatability was assessed by comparing the lumen, outer wall, and inner wall contours, as well as wall thickness, made by the two surgeons using the algorithm. Results: There was high correspondence between automatic and manual measurements for the lumen area (r=0.978 and r=0.996 for ruptured and unruptured aneurysms, respectively) and between vascular surgeons (r=0.987 and r=0.992 for ruptured and unruptured aneurysms, respectively). The authors' automatic algorithm showed better results when compared to the reference with an average lumen error of 3.69%, which is less than half the error between the commercially available application Simpleware and the reference (7.53%). Wall thickness measurements also showed good agreement between vascular surgeons with average coefficients of variation of 10.59% (ruptured aneurysms) and 13.02% (unruptured aneurysms). Ruptured aneurysms exhibit significantly thicker walls (1.78{+-}0.39 mm) than unruptured ones (1.48{+-}0.22 mm), p=0.044. Conclusions: While further refinement is needed to fully automate the outer wall segmentation algorithm, these preliminary results demonstrate the method's adequate reproducibility

  9. Shear wall experiments and design in Japan

    SciTech Connect

    Park, Y.J.; Hofmayer, C.

    1994-12-01

    This paper summarizes the results of recent survey studies on the available experimental data bases and design codes/standards for reinforced concrete (RC) shear wall structures in Japan. Information related to the seismic design of RC reactor buildings and containment structures was emphasized in the survey. The seismic requirements for concrete structures, particularly those related to shear strength design, are outlined. Detailed descriptions are presented on the development of Japanese shear wall equations, design requirements for containment structures, and ductility requirements.

  10. Method and apparatus for determining diameter and wall thickness of minute hollow spherical shells

    DOEpatents

    Steinman, David A.

    1982-01-01

    Method and apparatus for determining diameter and wall thickness of hollow microspheres or shells wherein terminal velocities of shells traveling in fluid-filled conduits of differing diameters are measured. A wall-effect factor is determined as a ratio of the terminal velocities, and shell outside diameter may then be ascertained as a predetermined empirical function of wall-effect factor. For shells of known outside diameter, wall thickness may then be ascertained as a predetermined empirical function of terminal velocity in either conduit.

  11. Method and apparatus for determining diameter and wall thickness of minute hollow spherical shells

    DOEpatents

    Steinman, D.A.

    1980-05-30

    Method and apparatus for determining diameter and wall thickness of hollow microspheres or shells wherein terminal velocities of shells traveling in fluid-filled conduits of differing diameters are measured. A wall-effect factor is determined as a ratio of the terminal velocities, and shell outside diameter may then be ascertained as a predetermined empirical function of wall-effect factor. For shells of known outside diameter, wall thickness may then be ascertained as a predetermined empirical function of terminal velocity in either conduit.

  12. Method of controlling the side wall thickness of a turbine nozzle segment for improved cooling

    DOEpatents

    Burdgick, Steven Sebastian

    2002-01-01

    A gas turbine nozzle segment has outer and inner bands and a vane extending therebetween. Each band has a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band has an inturned flange defining with the nozzle wall an undercut region. The outer surface of the side wall is provided with a step prior to welding the cover to the side wall. A thermal barrier coating is applied in the step and, after the cover is welded to the side wall, the side wall is finally machined to a controlled thickness removing all, some or none of the coating.

  13. Thermal variations of domain wall thickness and number of domains in magnetic rectangular grains

    NASA Astrophysics Data System (ADS)

    Xu, Song; Merrill, Ronald T.

    1990-12-01

    Equilibrium domain wall thickness and number of domains in rectangular magnetic grains are determined by using a modified Amar model. It is shown that domain structure, particularly domain wall thickness, in a magnetized grain depends strongly on grain shape and orientation. These dependencies are attributed to the existence of two competing self-magnetostatic interactions, one from the ends of the grain and the other from the sides. One of the consequences of this is that the thermal variation of domain wall thickness in an elongated grain is greater (smaller) than predicted by classical theory when the grain is magnetized along the shortest (longest) dimension. For magnetite, classical theory provides a good approximation in predicting both domain wall thickness and number of domains in equal-dimensional grains larger than about 4 μm.

  14. A microfluidic device approach to generate hollow alginate microfibers with controlled wall thickness and inner diameter

    NASA Astrophysics Data System (ADS)

    Pham, Uyen H. T.; Hanif, Madiha; Asthana, Amit; Iqbal, Samir M.

    2015-06-01

    Alginate is a natural polymer with inherent biocompatibility. A simple polydimethylsiloxane (PDMS) microfluidic device based self-assembled fabrication of alginate hollow microfibers is presented. The inner diameter as well as wall thickness of the microfibers were controlled effortlessly, by altering core and sheath flow rates in the microfluidic channels. The gelation/cross-linking occured while the solutions were ejected. The microfibers were generated spontaneously, extruding out of the outlet microchannel. It was observed that the outer diameter was independent of the flow rates, while the internal diameter and wall thickness of the hollow fibers were found to be functions of the core and sheath flow rates. At a constant sheath flow, with increasing core flow rates, the internal diameters increased and the wall thicknesses decreased. At a fixed core flow, when sheath flow rate increased, the internal diameters decreased and the wall thickness increased. The immobilization of enzymes in such hollow microfibers can be a potential application as microbioreactors.

  15. Gravity trapping on a finite thickness domain wall: An analytic study

    SciTech Connect

    Cvetic, Mirjam; Robnik, Marko

    2008-06-15

    We construct an explicit model of the gravity trapping domain-wall potential, where for the first time we can study explicitly the graviton wave function fluctuations for any thickness of domain wall. A concrete form of the potential depends on one parameter 0{<=}x{<=}({pi}/2), which effectively parameterizes the thickness of the domain wall with specific limits x{yields}0 and x{yields}({pi}/2) corresponding to the thin and the thick wall, respectively. The analysis of continuum Kaluza-Klein fluctuations yields explicit expressions for both small and large Kaluza-Klein energy. We also derive specific explicit conditions in the regime x>1, for which the fluctuation modes exhibit a resonance behavior, and which could sizably affect the modifications of the four-dimensional Newton's law at distances that typically are by 4 orders of magnitude larger than those relevant for Newton's law modifications of thin walls.

  16. Local and systemic effects of leg cycling training on arterial wall thickness in healthy humans.

    PubMed

    Thijssen, Dick H J; Dawson, Ellen A; van den Munckhof, Inge C L; Birk, Gurpreet K; Timothy Cable, N; Green, Daniel J

    2013-08-01

    Exercise training is associated with direct effects on conduit artery function and structure. Cross-sectional studies suggest the presence of systemic changes in wall thickness as a result of exercise in healthy subjects, but no previous study has examined this question in humans undertaking exercise training. To examine the change in superficial femoral (SFA, i.e. local effect) and carotid (CA, i.e. systemic effect) artery wall thickness across 8 weeks of lower limb cycle training in healthy young men. Fourteen healthy young male subjects were assigned to an 8-week training study of cycling exercise (n = 9) or a control period (n = 5). Before, during (2, 4 and 6 weeks) and after training, SFA and CA wall thickness was examined using automated edge-detection of high resolution ultrasound images. We also measured resting diameter and calculated the wall:lumen(W:L)-ratio. Exercise training did not alter CA or SFA baseline diameter (P = 0.14), but was associated with gradual, consistent and significant decreases in wall thickness and W:L-ratio in both the CA and SFA (P < 0.001 and 0.002, respectively). Two-way ANOVA revealed a comparable magnitude of decrease in wall thickness and W:L-ratio in both arteries across the 8-week period (interaction-effect; P = 0.29 and 0.12, respectively). No changes in artery diameter, wall thickness or W:L-ratio were apparent in controls (0.82, 0.38 and 0.52, respectively). We found that cycle exercise training in healthy young individuals is associated with modest, but significant, decreases in wall thickness in the superficial femoral and carotid arteries. These findings suggest that exercise training causes systemic adaptation of the arterial wall in healthy young subjects. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Artificial Climbing Wall Design and Use.

    ERIC Educational Resources Information Center

    Cinnamon, Jerry

    Climbing walls can be designed to satisfy the needs of both untrained and experienced climbers offering these people a place to learn their craft as well as a place for them to keep their skills honed during off seasons. Users of the artificial wall can be classified into special groups, such as "Youth at Risk," who are engaged in…

  18. Artificial Climbing Wall Design and Use.

    ERIC Educational Resources Information Center

    Cinnamon, Jerry

    Climbing walls can be designed to satisfy the needs of both untrained and experienced climbers offering these people a place to learn their craft as well as a place for them to keep their skills honed during off seasons. Users of the artificial wall can be classified into special groups, such as "Youth at Risk," who are engaged in…

  19. Influence and Modeling of Residual Stresses in Thick Walled Pressure Vessels with Through Holes

    DTIC Science & Technology

    2012-02-28

    Technical Report ARWSB-TR-12003 INFLUENCE AND MODELING OF RESIDUAL STRESSES IN THICK WALLED PRESSURE VESSELS WITH...DATE (DD-MM-YYYY) 28/02/2012 2. REPORT TYPE Technical Report 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Influence and Modeling of...Residual Stresses in Thick Walled Pressure Vessels with Through Holes 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  20. The study on ``load relief`` mechanism of multiple cracks in thick-wall cylinder

    SciTech Connect

    Zhang, Y.H.; Huang, Z.Z.; Tan, Y.; Chen, L.Y.; Pan, B.Z.

    1995-11-01

    In this paper, the stress field on a given cross section in a thick-wall cylinder with single or multiple cracks is analyzed by means of 3-D photoelastic. Based on the study of the effect of crack on stress field, the concept of ``Additional Bending Moment`` is presented and the expression for non-dimensional ABM, M, is derived. The ``load relief`` mechanism of multiple cracks in a thick-wall cylinder is studied.

  1. Comparison of Maximal Wall Thickness in Hypertrophic Cardiomyopathy Differs Between Magnetic Resonance Imaging and Transthoracic Echocardiography.

    PubMed

    Bois, John P; Geske, Jeffrey B; Foley, Thomas A; Ommen, Steve R; Pellikka, Patricia A

    2017-02-15

    Left ventricular (LV) wall thickness is a prognostic marker in hypertrophic cardiomyopathy (HC). LV wall thickness ≥30 mm (massive hypertrophy) is independently associated with sudden cardiac death. Presence of massive hypertrophy is used to guide decision making for cardiac defibrillator implantation. We sought to determine whether measurements of maximal LV wall thickness differ between cardiac magnetic resonance imaging (MRI) and transthoracic echocardiography (TTE). Consecutive patients were studied who had HC without previous septal ablation or myectomy and underwent both cardiac MRI and TTE at a single tertiary referral center. Reported maximal LV wall thickness was compared between the imaging techniques. Patients with ≥1 technique reporting massive hypertrophy received subset analysis. In total, 618 patients were evaluated from January 1, 2003, to December 21, 2012 (mean [SD] age, 53 [15] years; 381 men [62%]). In 75 patients (12%), reported maximal LV wall thickness was identical between MRI and TTE. Median difference in reported maximal LV wall thickness between the techniques was 3 mm (maximum difference, 17 mm). Of the 63 patients with ≥1 technique measuring maximal LV wall thickness ≥30 mm, 44 patients (70%) had discrepant classification regarding massive hypertrophy. MRI identified 52 patients (83%) with massive hypertrophy; TTE, 30 patients (48%). Although guidelines recommend MRI or TTE imaging to assess cardiac anatomy in HC, this study shows discrepancy between the techniques for maximal reported LV wall thickness assessment. In conclusion, because this measure clinically affects prognosis and therapeutic decision making, efforts to resolve these discrepancies are critical.

  2. Post-cast EDM method for reducing the thickness of a turbine nozzle wall

    DOEpatents

    Jones, Raymond Joseph; Bojappa, Parvangada Ganapathy; Kirkpatrick, Francis Lawrence; Schotsch, Margaret Jones; Rajan, Rajiv; Wei, Bin

    2002-01-01

    A post-cast EDM process is used to remove material from the interior surface of a nozzle vane cavity of a turbine. A thin electrode is passed through the cavity between opposite ends of the nozzle vane and displaced along the interior nozzle wall to remove the material along a predetermined path, thus reducing the thickness of the wall between the cavity and the external surface of the nozzle. In another form, an EDM process employing a profile as an electrode is disposed in the cavity and advanced against the wall to remove material from the wall until the final wall thickness is achieved, with the interior wall surface being complementary to the profile surface.

  3. Mapping of left ventricle wall thickness in mice using 11.7-T magnetic resonance imaging.

    PubMed

    Saito, Shigeyoshi; Masuda, Kasumi; Mori, Yuki; Nakatani, Satoshi; Yoshioka, Yoshichika; Murase, Kenya

    2017-02-01

    The left ventricle (LV) wall thickness is an important and routinely measured cardiologic parameter. Here we introduce three-dimensional (3D) mapping of LV wall thickness and function using a self-gated magnetic resonance (MR) sequence for ultra-high-field 11.7-T MR cine imaging of mouse hearts. Six male C57BL/6-j mice were subjected to 11.7-T MR imaging (MRI). Three standard views-short axis, long axis four-chamber, and long axis two-chamber-and eight consecutive short axis scans from the apex to base were performed for each mouse. The resulting 11 self-gated cine images were used for fast low-angle shot analysis with a navigator echo over an observation period of approximately 35min. The right ventricle (RV) and LV were identified in the short axis and four-chamber views. On 3D color-coded maps, the interventricular septum wall (diastole: 0.94±0.05mm, systole: 1.20±0.09mm) and LV free wall (diastole: 1.07±0.15mm, systole: 1.79±0.11mm) thicknesses were measured. This 3D wall thickness mapping technique can be used to observe regional wall thickness at the end-diastole and end-systole. Self-gated cine imaging based on ultra-high-field MRI can be used to accurately and easily measure cardiac function and wall thickness in normal mouse hearts. As in the preclinical study, this versatile and simple method will be clinically useful for the high-field-MRI evaluation of cardiac function and wall thickness. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Study of Individual Characteristic Abdominal Wall Thickness Based on Magnetic Anchored Surgical Instruments

    PubMed Central

    Dong, Ding-Hui; Liu, Wen-Yan; Feng, Hai-Bo; Fu, Yi-Li; Huang, Shi; Xiang, Jun-Xi; Lyu, Yi

    2015-01-01

    Background: Magnetic anchored surgical instruments (MASI), relying on magnetic force, can break through the limitations of the single port approach in dexterity. Individual characteristic abdominal wall thickness (ICAWT) deeply influences magnetic force that determines the safety of MASI. The purpose of this study was to research the abdominal wall characteristics in MASI applied environment to find ICAWT, and then construct an artful method to predict ICAWT, resulting in better safety and feasibility for MASI. Methods: For MASI, ICAWT is referred to the thickness of thickest point in the applied environment. We determined ICAWT through finding the thickest point in computed tomography scans. We also investigated the traits of abdominal wall thickness to discover the factor that can be used to predict ICAWT. Results: Abdominal wall at C point in the middle third lumbar vertebra plane (L3) is the thickest during chosen points. Fat layer thickness plays a more important role in abdominal wall thickness than muscle layer thickness. “BMI-ICAWT” curve was obtained based on abdominal wall thickness of C point in L3 plane, and the expression was as follow: f(x) = P1 × x2 + P2 × x + P3, where P1 = 0.03916 (0.01776, 0.06056), P2 = 1.098 (0.03197, 2.164), P3 = −18.52 (−31.64, −5.412), R-square: 0.99. Conclusions: Abdominal wall thickness of C point at L3 could be regarded as ICAWT. BMI could be a reliable predictor of ICAWT. In the light of “BMI-ICAWT” curve, we may conveniently predict ICAWT by BMI, resulting a better safety and feasibility for MASI. PMID:26228215

  5. Assessment of the chest wall thickness of the lawrence livermore torso phantom using a voxel image.

    PubMed

    Ahmed, A S M Sabbir; Capello, Kevin; Kramer, Gary H

    2011-06-01

    This paper describes the methodology of measuring the chest wall thickness using the voxel image of the Lawrence Livermore National Lab (LLNL) torso phantom. The LLNL phantom is used as a standard to calibrate a lung counter consisting of a 2 × 2 array of germanium detectors. In general, an average thickness estimated from four counting positions is used as the chest wall thickness for a given overlay plate. For a given overlay, the outer chest surface differs from that of inner one, and the chest wall thickness varies from one position to other. The LLNL phantom with chest plate and C4 overlay plate installed was scanned with a CT (computed tomography) scanner. The image data, collected in DICOM (Digital Imaging and Communication) format, were converted to the MCNP input file by using the Scan2Mcnp program. The MCNP file was visualized and analyzed with the Moritz visual editor. An analytic expression was formulated and solved to calculate the chest wall thickness by using the point detector responses (F 5 tally of MCNP). To map the chest thickness, the entire chest wall was meshed into virtual grids of 1 cm width. A source and detector pair was moved along the inner and outer surface of the chest wall from right to left at different heights from neck to abdomen. For each height (z(k)), (x(i), y(j)) coordinates for the detector source pair were calculated from the visual editor and were scaled on-screen. For each (x(i), y(j), z(k)) position, a mesh thickness was measured from on-screen measurement and by solving the detector responses. The chest wall thicknesses at different positions on the outer surface of the chest were compared and verified using two methods.

  6. Effect of polyisobutylene on ethyl cellulose-walled microcapsules: wall structure and thickness of salicylamide and theophylline microcapsules.

    PubMed

    Benita, S; Donbrow, M

    1982-02-01

    Microcapsules were prepared by the ethylcellulose coacervation process which is based on the differential thermal solubility in cyclohexane. When a protective colloid, polyisobutylene, was present in adequate concentration, individually film-coated core particles formed. However, they were accompanied by small empty coacervate droplets, detectable by microscopic observation. Below the critical colloid concentration, the product had the form of aggregate, in contrast to individual film-coated microcapsules. Increase of colloid concentration yielded microcapsules of higher drug content, because coating became progressively thinner; there was a corresponding increase in the release rate of drugs from the microcapsules. Since the initial wall polymer/drug ratio and the particle size are constant, the drug content varied with the thicknesses of the wall membrane. This is shown here by removal of empty coacervate droplets by repeated decantations, enabling determination of drug content by chemical analysis. In contrast to results reported in the literature, in the presence of a protective colloid, microcapsule drug content decreased with decreasing particle size of the drug. This was caused by more complete uptake of the wall polymer on the increased surface of core material. The effect of protective colloid concentration on the apparent loss of wall polymer as empty droplets closely paralleled its effect on the size of stabilized droplet formation is a side reaction when core material is present, causing changes in wall thickness. This reaction not only affects the efficiency of the coating process but may be utilized to control wall thickness. First-order constants for drug release from salicylamide and theophylline microcapsules followed the same pattern as wall thickness and confirmed the validity of the measurements.

  7. Cross-Barrel Temperature Difference Due to Wall Thickness Variation

    DTIC Science & Technology

    1993-03-01

    atmosphere. F Is the radiation interchange factor between the barrel outer wall and the environment (in our case, we assume F = 0.95), and a is the Stefan ...barrel metal [kg/mrJ o Stefan -Boltzmann constant = 5.669 x 10-8 J/(m2 s K4) * azimuthal coordinate In transverse plane azimuthal coordinate in...Pomey SMCAR-CCB-DS, P. Votlis Fort Knox, KY 40121-5212 SMCAR-CCB-DS, C. Andrade SMCAR-LBD-D, J. Zweig 1 Paul Gough Associates, Inc. SMCAR-CCB, L

  8. [The cutaneous groin flap for coverage of a full-thickness abdominal wall defect].

    PubMed

    Doebler, O; Spierer, R

    2010-08-01

    A full-thickness defect of the abdominal wall is rare and may occur as a complication of extended abdominal surgery procedures. We report about a 69-year-old patient who was presented to our department with a full-thickness abdominal wall defect and a fully exposed collagen-mesh for reconstructive wound closure. 13 operations with resections of necrotic parts of the abdominal wall were performed following a complicated intraabdominal infection. After debridement and mesh explantation, closure of the remaining defect of the lower abdominal region was achieved by a cutaneous groin flap.

  9. Applications of Green Walls in Urban Design

    NASA Astrophysics Data System (ADS)

    Virtudes, Ana; Manso, Maria

    2016-10-01

    Green walls are a choice towards achieving sustainable urban rehabilitation, due to the lack of free space in the consolidated urban fabric. Nowadays, green walls are considered to be an innovation in the fields of ecology, horticulture or buildings. Nevertheless, in the domain of urban design, they are still surprising and unexpected ideas. Thus, this research aims to reflect on green walls as a feature in urban design and rehabilitation, identifying the advantages of their utilization as an enhancement of the quality of city's image, especially in dense urban areas. It aims to demonstrate some practical applications of green walls in urban design proposals, showing model solutions and their real application in several architectural examples.

  10. High resolution computed tomographic evaluation of bronchial wall thickness in healthy and clinically asthmatic cats

    PubMed Central

    WON, Sungjun; YUN, Sookyung; LEE, Jeosoon; LEE, Mikyung; CHOI, Mincheol; YOON, Junghee

    2017-01-01

    The objective of study is to determine the thickness of bronchial walls of clinically diagnosed asthmatic cats using high resolution computed tomography (HRCT) compared to that of healthy cats. The bronchial walls and pulmonary arteries were measured in healthy 16 cats and clinically asthmatic 4 cats. The bronchial walls and pulmonary arteries were measured under general anesthesia with positive pressure inspiration using HRCT. In healthy and asthmatic cats, bronchial lumen to the artery ratio (BA ratio), the ratio of bronchial wall thickness to bronchial diameter (TD ratio) and ratio of bronchial wall thickness to pulmonary artery (TA ratio) were measured. The mean BA ratio, TD ratio and TA ratio in healthy cats were 0.86 ± 0.12, 0.18 ± 0.02 and 0.25 ± 0.05, respectively. Under the same condition, the mean BA ratio, TD ratio and TA ratio in asthmatic cats were 0.93 ± 0.21, 0.22 ± 0.24 and 0.37 ± 0.06. The TD ratio and TA ratio in asthmatic cats were significantly higher than healthy cats (P<0.001). BA ratio was not significantly different in both groups (P>0.05). The evaluation of bronchial wall thickness by HRCT could be useful for diagnosis of disease of bronchial wall thickening, such as feline asthma. PMID:28163274

  11. Chest wall thickness measurements: The alternative approach extended for {sup 241}Am

    SciTech Connect

    Kramer, G.H.; Burns, L.C.

    1997-02-01

    The Human Monitoring Laboratory has extended the technique of determining the chest wall thickness of an individual using information from the spectrum produced by internally deposited radionuclides. The technique has been investigated both theoretically and practically using germanium detectors and the Lawrence Livermore Torso Phantom. The phantom was used with a lung set containing homogeneously distributed {sup 241}Am. Chest wall thicknesses were varied by using a series of muscle equivalent overlay plates that gave a range of 1.6 cm to 3.9 cm thickness. It was found that a 3-cm chest wall thickness can be estimated to within 18%. Using a spectral addition technique 1 kBq was estimated to be the {open_quotes}practical{close_quotes} lower limit of activity for this method. 7 refs., 2 figs., 3 tabs.

  12. A Probabilistic Method for Estimation of Bowel Wall Thickness in MR Colonography

    PubMed Central

    Menys, Alex; Jaffer, Asif; Bhatnagar, Gauraang; Punwani, Shonit; Atkinson, David; Halligan, Steve; Hawkes, David J.; Taylor, Stuart A.

    2017-01-01

    MRI has recently been applied as a tool to quantitatively evaluate the response to therapy in patients with Crohn’s disease, and is the preferred choice for repeated imaging. Bowel wall thickness on MRI is an important biomarker of underlying inflammatory activity, being abnormally increased in the acute phase and reducing in response to successful therapy; however, a poor level of interobserver agreement of measured thickness is reported and therefore a system for accurate, robust and reproducible measurements is desirable. We propose a novel method for estimating bowel wall-thickness to improve the poor interobserver agreement of the manual procedure. We show that the variability of wall thickness measurement between the algorithm and observer measurements (0.25mm ± 0.81mm) has differences which are similar to observer variability (0.16mm ± 0.64mm). PMID:28072831

  13. A Probabilistic Method for Estimation of Bowel Wall Thickness in MR Colonography.

    PubMed

    Hampshire, Thomas; Menys, Alex; Jaffer, Asif; Bhatnagar, Gauraang; Punwani, Shonit; Atkinson, David; Halligan, Steve; Hawkes, David J; Taylor, Stuart A

    2017-01-01

    MRI has recently been applied as a tool to quantitatively evaluate the response to therapy in patients with Crohn's disease, and is the preferred choice for repeated imaging. Bowel wall thickness on MRI is an important biomarker of underlying inflammatory activity, being abnormally increased in the acute phase and reducing in response to successful therapy; however, a poor level of interobserver agreement of measured thickness is reported and therefore a system for accurate, robust and reproducible measurements is desirable. We propose a novel method for estimating bowel wall-thickness to improve the poor interobserver agreement of the manual procedure. We show that the variability of wall thickness measurement between the algorithm and observer measurements (0.25mm ± 0.81mm) has differences which are similar to observer variability (0.16mm ± 0.64mm).

  14. Chest wall thickness measurements of the LLNL and JAERI torso phantoms for germanium detector counting

    SciTech Connect

    Kramer, G.H.; Hauck, B.M.

    1997-11-01

    The Lawrence Livermore National Laboratory and Japanese Atomic Energy Research Institute torso phantoms were developed to calibrate lung counting systems that are used to estimate plutonium and other radionuclides deposited in the lung. Originally, low energy photon counting systems consisted of phoswich detectors. The average chest wall thicknesses and individual measurement points of the Lawrence Livermore National Laboratory phantom and its overlay plates in the regions covered by these detectors were provided by the manufacturer. Germanium detectors are of a different size and are placed in different locations on the phantom so that the manufacturer`s data are no longer applicable for the locations of the germanium detectors on the phantom. The Human Monitoring Laboratory has re-evaluated the chest wall thickness of both the Lawrence Livermore National Laboratory and Japanese Atomic Energy Research Institute phantoms and their overlay plates for its germanium lung counting system. The measurements were made in the upper right, lower right, upper left, and lower left positions on the phantom`s torso plate above the lungs. The effective chest wall thicknesses (17 keV) for the Lawrence Livermore National Laboratory torso plate are 1.46 cm, 1.43 cm, 1.66 cm, 1.48 cm, respectively. The manufacturer`s quoted average effective chest wall thickness for a pair of phoswich detectors is 1.63 cm. The measured effective chest wall thicknesses (17 keV) for the JAERI`s torso plate are 1.76 cm, 2.15 cm, 1.79 cm, 2.15 cm, respectively. The manufacturer`s quoted average chest wall thickness for an unspecified region of the chest is 1.50 cm. This paper presents effective chest wall thickness data for the phantoms with and without their overlay plates at 17 keV, 60 keV, 200 keV and 1,500 keV. 13 refs., 2 figs., 4 tabs.

  15. Acoustic scattering from a contrast agent microbubble near an elastic wall of finite thickness

    NASA Astrophysics Data System (ADS)

    Doinikov, Alexander A.; Aired, Leila; Bouakaz, Ayache

    2011-11-01

    Interest in the problem under consideration in this study is motivated by targeted ultrasound imaging where one has to deal with microbubble contrast agents pulsating near blood vessel walls. A modified Rayleigh-Plesset equation is derived that describes the oscillation of a contrast agent microbubble near an elastic wall of finite thickness. It is assumed that the medium behind the wall is a fluid but it is shown that the equation obtained is easily transformable to the case that the medium behind the wall is an elastic solid. In contrast to the model of a rigid wall, which predicts decreasing natural frequency of a bubble near the wall, the elastic wall model reveals that the bubble natural frequency can both decrease and increase, and in cases of interest for medical applications, the bubble natural frequency usually increases. It is found that the influence of an elastic wall on the acoustic response of a bubble is determined by the ratio between a cumulative parameter, which integrally characterizes the mechanical properties of the wall and has the dimension of density, and the density of the liquid surrounding the bubble. It is shown that the acoustic influence of the arterial wall on the bubble is weak and apparently cannot be used to recognize the moment when the bubble approaches the wall. However, in experiments where the behavior of bubbles near various plastic walls is observed, changes in the bubble response, such as increasing natural frequency and decreasing oscillation amplitude, are detectable.

  16. Influence of wall thickness and properties of structural materials on the discharge temperature and strength characteristics of slow-speed long-stroke stages

    NASA Astrophysics Data System (ADS)

    Yusha, V. L.; Busarov, S. S.; Aistov, I. P.; Titov, D. S.; Vansovich, K. A.

    2017-08-01

    The article analyzes the influence of the wall thickness of the working chamber cylinder on the cooling efficiency of the compressed gas with the required strength. The obtained results indicate an ambiguous decision regarding the choice of the wall thickness. The performed calculations make it possible to develop the design of the stage, using, depending on the situation, one or another priority criterion (the minimum temperature of the compressed gas, the cost, or the mass of the stage).

  17. Experiments on fracture toughness of thick-wall cylinder for modes I, II, III

    SciTech Connect

    Saegusa, T.; Urabe, N.; Ito, C.; Shirai, K.; Kosaki, A.

    1999-07-01

    There have been few data on fracture toughness for Mode 2 and 3 as compared with those for Mode 1. Experimental data on fracture toughness of plates made of ductile cast iron (ASTM A874-89) and forged steel (ASME SA350 LF5 C1.1) were obtained at a temperature range from 77K to 293K for Mode 1, 2 and 3. The results showed: J{sub IC} < J{sub IIC} < J{sub IIIC}, and K{sub IC} < K{sub IIC} K{sub IIIC}. Integrity of a thick-wall cylinder with artificial flaw was demonstrated against brittle fracture at 233K for Mode 1, 2 and 3, which is one of the design requirements of containers shipping radioactive materials.

  18. Laser Ultrasonic Thickness Measurements of Very Thick Walls at High Temperatures

    SciTech Connect

    Kruger, S. E.; Lord, M.; Monchalin, J.-P.

    2006-03-06

    Laser-ultrasonics presents many advantages compared to conventional ultrasonics, but is, generally, considered as less sensitive. As a consequence, laser-ultrasonics should not be adequate for ultrasonic measurements in coarse microstructure materials or measurements of large thicknesses. However, since the generated waves extend to very low frequencies, measurements in such conditions can be successfully performed if a photorefractive interferometer sensitive also to these low frequencies and properly balanced is used for detection. This is demonstrated by measurements of thicknesses up to 100 mm (4'') for various steel grades and at temperatures up to 1250 deg. C.

  19. Collapse pressure analysis of transversely isotropic thick-walled cylinder using Lebesgue strain measure and transition theory.

    PubMed

    Aggarwal, A K; Sharma, Richa; Sharma, Sanjeev

    2014-01-01

    The objective of this paper is to provide guidance for the design of the thick-walled cylinder made up of transversely isotropic material so that collapse of cylinder due to influence of internal and external pressure can be avoided. The concept of transition theory based on Lebesgue strain measure has been used to simplify the constitutive equations. Results have been analyzed theoretically and discussed numerically. From this analysis, it has been concluded that, under the influence of internal and external pressure, circular cylinder made up of transversely isotropic material (beryl) is on the safer side of the design as compared to the cylinders made up of isotropic material (steel). This is because of the reason that percentage increase in effective pressure required for initial yielding to become fully plastic is high for beryl as compared to steel which leads to the idea of "stress saving" that reduces the possibility of collapse of thick-walled cylinder due to internal and external pressure.

  20. Multimodal optical measurement in vitro of surface deformations and wall thickness of the pressurized aortic arch.

    PubMed

    Genovese, Katia; Humphrey, Jay D

    2015-04-01

    Computational modeling of arterial mechanics continues to progress, even to the point of allowing the study of complex regions such as the aortic arch. Nevertheless, most prior studies assign homogeneous and isotropic material properties and constant wall thickness even when implementing patient-specific luminal geometries obtained from medical imaging. These assumptions are not due to computational limitations, but rather to the lack of spatially dense sets of experimental data that describe regional variations in mechanical properties and wall thickness in such complex arterial regions. In this work, we addressed technical challenges associated with in vitro measurement of overall geometry, full-field surface deformations, and regional wall thickness of the porcine aortic arch in its native anatomical configuration. Specifically, we combined two digital image correlation-based approaches, standard and panoramic, to track surface geometry and finite deformations during pressurization, with a 360-deg fringe projection system to contour the outer and inner geometry. The latter provided, for the first time, information on heterogeneous distributions of wall thickness of the arch and associated branches in the unloaded state. Results showed that mechanical responses vary significantly with orientation and location (e.g., less extensible in the circumferential direction and with increasing distance from the heart) and that the arch exhibits a nearly linear increase in pressure-induced strain up to 40%, consistent with other findings on proximal porcine aortas. Thickness measurements revealed strong regional differences, thus emphasizing the need to include nonuniform thicknesses in theoretical and computational studies of complex arterial geometries.

  1. Exercise-mediated changes in conduit artery wall thickness in humans: role of shear stress.

    PubMed

    Thijssen, Dick H J; Dawson, Ellen A; van den Munckhof, Inge C L; Tinken, Toni M; den Drijver, Evert; Hopkins, Nicola; Cable, N Timothy; Green, Daniel J

    2011-07-01

    Episodic increases in shear stress have been proposed as a mechanism that induces training-induced adaptation in arterial wall remodeling in humans. To address this hypothesis in humans, we examined bilateral brachial artery wall thickness using high-resolution ultrasound in healthy men across an 8-wk period of bilateral handgrip training. Unilaterally, shear rate was attenuated by cuff inflation around the forearm to 60 mmHg. Grip strength, forearm volume, and girth improved similarly between the limbs. Acute bouts of handgrip exercise increased shear rate (P < 0.005) in the noncuffed limb, whereas cuff inflation successfully decreased exercise-induced increases in shear. Brachial blood pressure responses similarly increased during exercise in both the cuffed and noncuffed limbs. Handgrip training had no effect on baseline brachial artery diameter, blood flow, or shear rate but significantly decreased brachial artery wall thickness after 6 and 8 wk (ANOVA, P < 0.001) and wall-to-lumen ratio after week 8 (ANOVA, P = 0.005). The magnitude of decrease in brachial artery wall thickness and wall-to-lumen ratio after exercise training was similar in the noncuffed and cuffed arms. These results suggest that exercise-induced changes in shear rate are not obligatory for arterial wall remodeling during a period of 8 wk of exercise training in healthy humans.

  2. Radical tumor excision and immediate abdominal wall reconstruction in patients with aggressive neoplasm compromised full-thickness lower abdominal wall.

    PubMed

    Yang, Fei

    2013-01-01

    Radical tumor resection and immediate lower abdominal wall reconstruction in patients with aggressive neoplasm invading full-thickness abdominal wall are challenging because of their close proximity and possible invasion to bone and great vessels, as well as consequent giant defect. Data on 16 patients were reviewed retrospectively. Radical neoplasm resection and immediate abdominal wall reconstruction using the combined technique of intraperitoneal mesh placement, sublay technique, pedicled great omentum flap, and rotation skin graft were performed. Sixteen patients underwent radical abdominal wall neoplasm resection, achieving clear margin of >3 cm. The mean size of consequent giant defect was 226.5 ± 65.5 cm(2), with a mean polypropylene mesh size of 160.7 ± 40.5 cm(2) and a mean compound mesh size of 330.8 ± 100.2 cm(2). Sixteen patients had a mean follow-up duration of 32.5 ± 12.5 months. Four patients developed incisional infections, and 1 patient died of several metastatic lesions 24 months postoperatively. No ventral hernia and abdominal wall recurrence were observed. Radical neoplasm resection and immediate abdominal wall reconstruction are appropriate for patients with aggressive neoplasm in the lower abdominal wall. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. [An example of multi-stage reconstruction of a full-thickness abdominal wall defect].

    PubMed

    Kaczmarzyk, Janusz; Elsaftawy, Ahmed; Jabłecki, Jerzy; Kaczmarzyk, Leszek

    2013-01-01

    Abdominal wall reconstruction is a highly complex procedure that may requires a multiple stages surgical operations. The aim of a such reconstruction is to close the abdominal wall defect and to create a support for the internal organs. It's a challenge for both general and reconstructive surgery. An incomplete thickness defects of the abdominal wall are so much easier to challenge than complete ones. Also the size of the primary defect determines the way and stages of the operation. Such defects can occur in necrotizing fasciitis of the abdominal wall, after abdominal walls tumors removal, in traffic accidents or after "open abdomen" procedures (acute severe pancreatitis). In this paper the authors present a case of 62-yo patient which was operated because of large intestine perforation with various complications of which the most serious was the abdominal wall defect.

  4. Accurate Wall Loss Determination in Accelerator Design

    SciTech Connect

    Ge, L

    2004-05-13

    While the parallel finite element eigensolver Omega3P has shown to be able to calculate RF cavity mode frequencies to very high precision, it has become increasingly necessary that wall loss be determined with high accuracy as well because: (1) the wall loss leads to shunt impedance degradation and (2) excessive wall loss results in undesirable RF pulse heating. These issues need to be adequately addressed in next generation accelerators such as the NLC in which accelerator structures are designed to operate at high efficiency and high power. This paper will present results from an ongoing effort to improve wall loss calculations with Omega3P and with a new parallel S-matrix solver S3P through higher order mesh elements and adaptive refinement strategies.

  5. Thickness measuring of electroconductive pipe walls using the dual-frequency eddy-current method

    NASA Astrophysics Data System (ADS)

    Yakimov, Evgeny; Galtseva, Olga; Ustyugov, Daniil

    2017-01-01

    The paper describes a dual-frequency method for reducing the impact of changes in the gap size between the eddy-current transducer and the pipe, as well as the pipe electrical conductivity on the eddy-current thickness gauge readings. A block-diagram of the dual-frequency eddy-current thickness gauge is proposed for light-alloy drill pipes. The amplitude and signal phase dependencies on the wall thickness in the range from 6 to 17 mm and the gap in the range from 0 to 13.5 mm were studied, the results are presented. The digital signal processing algorithms based on the piecewise-linear approximation of low-frequency and high-frequency signal phase dependencies on the wall thickness are proposed. It is shown that the proposed correction algorithms can reduce the error caused by variations of electrical conductivity and the gap between the transducer and the pipe.

  6. Colonic wall thickness, pancreatic enzyme dose and type of preparation in cystic fibrosis

    PubMed Central

    Ramsden, W; Moya, E; Littlewood, J

    1998-01-01

    Increased colonic wall thickness has been reported in patients exposed to large doses of high strength pancreatic enzyme preparations who did not develop fibrosing colonopathy. This has been interpreted as evidence for a spectrum of subclinical disease. The relation between sonographically measured colonic wall thickness and pancreatic enzyme preparation and dose was studied in 86 children with cystic fibrosis (CF). Colonic wall thickness of a control group was also measured. The average thickness in all colonic regions was higher in the CF group (overall average range 0.7-2.5 mm v 0.6-1.4 mm in the control group). There was no significant relation between colonic wall thickness and age, sex, total dose of lipase, or copolymer. Apart from one patient with an early colonic stricture, none of those exposed to high doses of lipase, or the methacrylic acid copolymer Eudragit L30 D55, showed evidence of subclinical damage to the colon. The reproducibility of the sonographic measurements was poor.

 PMID:9875045

  7. An exact solution for a thick domain wall in general relativity

    NASA Technical Reports Server (NTRS)

    Goetz, Guenter; Noetzold, Dirk

    1989-01-01

    An exact solution of the Einstein equations for a static, planar domain wall with finite thickness is presented. At infinity, density and pressure vanish and the space-time tends to the Minkowski vacuum on one side of the wall and to the Taub vacuum on the other side. A surprising feature of this solution is that the density and pressure distribution are symmetric about the central plane of the wall whereas the space-time metric and therefore also the gravitational field experienced by a test particle is asymmetric.

  8. Wall-Thickness Dependence of Cooling-Induced Deformation of Polystyrene Spherical Shells

    SciTech Connect

    Endo, T.; Kobayashi, N.; Goto, K.; Yasuda, M.; Fujima, Y.

    2003-05-15

    Experiments on the wall-thickness dependence of the cooling-induced deformation (CID) of polystyrene (PS) spherical shells were carried out. For the experiments, the PS shells were fabricated by the density-matched emulsion method using the hand-shaken microencapsulation technique. The number-averaged and weight-averaged molecular weights of the PS were M{sub n} 1.1 x 10{sup 5} and M{sub w} = 4.0 x 10{sup 5}, respectively. The diameter of the PS shells was {approx}400-550 {mu}m. To investigate the wall-thickness dependence of the CID, the wall thickness of the PS shells was varied between 5 and 60 {mu}m. In the experiments, the PS shells were cooled by using liquid nitrogen, and their images were captured at 0 and -190 deg. C. For the investigation of the CID, two shapes of each shell that were measured at 0 and -190 deg. C were compared. The thinner PS shells showed larger CID. The maximum deformation was almost 1% of the outer radius when the shell aspect ratio (outer radius)/(wall thickness) was higher than 20. The repeatability of the CID was studied, and the results implied that residual stress in the PS shells had an influence on the CID.

  9. Boll wall thickness in four cotton species and susceptibility to stink bug feeding

    USDA-ARS?s Scientific Manuscript database

    Southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae), adults can introduce pathogens into cotton bolls while feeding. Stylet penetration estimates of southern green stink bugs are known, and knowledge of boll wall thickness in cotton species may aid in determining susceptibility...

  10. Magnet Fall inside a Conductive Pipe: Motion and the Role of the Pipe Wall Thickness

    ERIC Educational Resources Information Center

    Donoso, G.; Ladera, C. L.; Martin, P.

    2009-01-01

    Theoretical models and experimental results are presented for the retarded fall of a strong magnet inside a vertical conductive non-magnetic tube. Predictions and experimental results are in good agreement modelling the magnet as a simple magnetic dipole. The effect of varying the pipe wall thickness on the retarding magnetic drag is studied for…

  11. Magnet Fall inside a Conductive Pipe: Motion and the Role of the Pipe Wall Thickness

    ERIC Educational Resources Information Center

    Donoso, G.; Ladera, C. L.; Martin, P.

    2009-01-01

    Theoretical models and experimental results are presented for the retarded fall of a strong magnet inside a vertical conductive non-magnetic tube. Predictions and experimental results are in good agreement modelling the magnet as a simple magnetic dipole. The effect of varying the pipe wall thickness on the retarding magnetic drag is studied for…

  12. Automatic Thickness and Volume Estimation of Sprayed Concrete on Anchored Retaining Walls from Terrestrial LIDAR Data

    NASA Astrophysics Data System (ADS)

    Martínez-Sánchez, J.; Puente, I.; GonzálezJorge, H.; Riveiro, B.; Arias, P.

    2016-06-01

    When ground conditions are weak, particularly in free formed tunnel linings or retaining walls, sprayed concrete can be applied on the exposed surfaces immediately after excavation for shotcreting rock outcrops. In these situations, shotcrete is normally applied conjointly with rock bolts and mesh, thereby supporting the loose material that causes many of the small ground falls. On the other hand, contractors want to determine the thickness and volume of sprayed concrete for both technical and economic reasons: to guarantee their structural strength but also, to not deliver excess material that they will not be paid for. In this paper, we first introduce a terrestrial LiDAR-based method for the automatic detection of rock bolts, as typically used in anchored retaining walls. These ground support elements are segmented based on their geometry and they will serve as control points for the co-registration of two successive scans, before and after shotcreting. Then we compare both point clouds to estimate the sprayed concrete thickness and the expending volume on the wall. This novel methodology is demonstrated on repeated scan data from a retaining wall in the city of Vigo (Spain), resulting in a rock bolts detection rate of 91%, that permits to obtain a detailed information of the thickness and calculate a total volume of 3597 litres of concrete. These results have verified the effectiveness of the developed approach by increasing productivity and improving previous empirical proposals for real time thickness estimation.

  13. The influence of clinical and genetic factors on left ventricular wall thickness in Ragdoll cats.

    PubMed

    Borgeat, Kieran; Stern, Joshua; Meurs, Kathryn M; Fuentes, Virginia Luis; Connolly, David J

    2015-12-01

    To investigate the effect of various genetic and environmental modifiers on left ventricular (LV) wall thickness in a cohort of cats genotyped for the myosin binding protein C3 mutation (MYBPC3). Sixty-four Ragdoll cats. All cats were screened for HCM with echocardiography and genotyping for the HCM-associated MYBPC3:R820W mutation. Cats were also genotyped for previously identified variant polymorphisms of the angiotensin-converting enzyme (ACE) and cardiac beta-adrenergic receptor (ADRB1) genes. Plasma N-terminal pro-B-type natriuretic peptide and cardiac troponin I were also measured. Associations were evaluated between genotype (MYBPC3 negative/positive, and ACE and ADRB1 negative/heterozygous/homozygous), patient factors (body weight, age and sex) and echocardiographic measurements of LV wall thickness. Male cats had greater maximum wall thickness (LVmax; 5.8 mm, IQR 5.1-6.4 mm) than females (4.7 mm, IQR 4.4-5.3 mm, p = 0.002). Body weight positively correlated with LVmax (ρ = 0.604, p < 0.001). The MYBPC3:R820W-positive cats had a greater LVmax (5.44 mm, IQR 4.83-6.28 mm) than the negative cats (4.76 mm, IQR 4.36-5.32 mm, p = 0.001). Also, the ACE polymorphism genotype was associated with LVmax: the homozygous cats (5.37 mm, IQR 5.14-6.4 mm) had greater LVmax than the heterozygous cats (4.73 mm, IQR 4.41-5.55 mm, p = 0.014). Only the MYBPC3 genotype and body weight were independently associated with wall thickness in multivariable analysis. This study provides evidence that the MYBPC3:R820W mutation is independently associated with LV wall thickness in Ragdoll cats. Body weight is also independently associated with maximum LV wall thickness, but is not currently accounted for in HCM screening. In addition, other genetic modifiers may be associated with variation in LV wall thickness in Ragdolls. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Room temperature synthesis of indium tin oxide nanotubes with high precision wall thickness by electroless deposition

    PubMed Central

    Ionescu, Emanuel; Fu, Ganhua; Ensinger, Wolfgang

    2011-01-01

    Summary Conductive nanotubes consisting of indium tin oxide (ITO) were fabricated by electroless deposition using ion track etched polycarbonate templates. To produce nanotubes (NTs) with thin walls and small surface roughness, the tubes were generated by a multi-step procedure under aqueous conditions. The approach reported below yields open end nanotubes with well defined outer diameter and wall thickness. In the past, zinc oxide films were mostly preferred and were synthesized using electroless deposition based on aqueous solutions. All these methods previously developed, are not adaptable in the case of ITO nanotubes, even with modifications. In the present work, therefore, we investigated the necessary conditions for the growth of ITO-NTs to achieve a wall thickness of around 10 nm. In addition, the effects of pH and reductive concentrations for the formation of ITO-NTs are also discussed. PMID:21977422

  15. Room temperature synthesis of indium tin oxide nanotubes with high precision wall thickness by electroless deposition.

    PubMed

    Boehme, Mario; Ionescu, Emanuel; Fu, Ganhua; Ensinger, Wolfgang

    2011-01-01

    Conductive nanotubes consisting of indium tin oxide (ITO) were fabricated by electroless deposition using ion track etched polycarbonate templates. To produce nanotubes (NTs) with thin walls and small surface roughness, the tubes were generated by a multi-step procedure under aqueous conditions. The approach reported below yields open end nanotubes with well defined outer diameter and wall thickness. In the past, zinc oxide films were mostly preferred and were synthesized using electroless deposition based on aqueous solutions. All these methods previously developed, are not adaptable in the case of ITO nanotubes, even with modifications. In the present work, therefore, we investigated the necessary conditions for the growth of ITO-NTs to achieve a wall thickness of around 10 nm. In addition, the effects of pH and reductive concentrations for the formation of ITO-NTs are also discussed.

  16. Reduction in left ventricular wall thickness after deconditioning in highly trained Olympic athletes.

    PubMed Central

    Maron, B J; Pelliccia, A; Spataro, A; Granata, M

    1993-01-01

    BACKGROUND--Clinical distinction between athlete's heart and hypertrophic cardiomyopathy in a trained athlete is often difficult. In an effort to identify variables that may aid in this differential diagnosis, the effects of deconditioning on left ventricular wall thickness were assessed in six highly trained elite athletes who had competed in rowing or canoeing at the 1988 Seoul Olympic Games. Each of these athletes showed substantial ventricular septal thickening associated with training (13-15 mm) which resembled that of hypertrophic cardiomyopathy. METHODS--The athletes voluntarily reduced their training substantially for 6-34 weeks (mean 13) after the Olympic competition. Echocardiography was performed at peak training and also after deconditioning, and cardiac dimensions were assessed blindly. RESULTS--Maximum ventricular septal thickness was 13.8 (0.9) mm in the trained state and 10.5 (0.5) in the deconditioned state (p < 0.005) (change 15-33%). CONCLUSIONS--The finding that deconditioning may be associated with a considerable reduction in ventricular septal thickness in elite athletes over short periods strongly suggests that these athletes had a physiological form of left ventricular hypertrophy induced by training. Such a reduction in wall thickness with deconditioning may help to distinguish between the physiological hypertrophy of athlete's heart and primary pathological hypertrophy (for example, hypertrophic cardiomyopathy) in selected athletes with increased left ventricular wall thickness. Images PMID:8435237

  17. Quantification of esophageal wall thickness in CT using atlas-based segmentation technique

    NASA Astrophysics Data System (ADS)

    Wang, Jiahui; Kang, Min Kyu; Kligerman, Seth; Lu, Wei

    2015-03-01

    Esophageal wall thickness is an important predictor of esophageal cancer response to therapy. In this study, we developed a computerized pipeline for quantification of esophageal wall thickness using computerized tomography (CT). We first segmented the esophagus using a multi-atlas-based segmentation scheme. The esophagus in each atlas CT was manually segmented to create a label map. Using image registration, all of the atlases were aligned to the imaging space of the target CT. The deformation field from the registration was applied to the label maps to warp them to the target space. A weighted majority-voting label fusion was employed to create the segmentation of esophagus. Finally, we excluded the lumen from the esophagus using a threshold of -600 HU and measured the esophageal wall thickness. The developed method was tested on a dataset of 30 CT scans, including 15 esophageal cancer patients and 15 normal controls. The mean Dice similarity coefficient (DSC) and mean absolute distance (MAD) between the segmented esophagus and the reference standard were employed to evaluate the segmentation results. Our method achieved a mean Dice coefficient of 65.55 ± 10.48% and mean MAD of 1.40 ± 1.31 mm for all the cases. The mean esophageal wall thickness of cancer patients and normal controls was 6.35 ± 1.19 mm and 6.03 ± 0.51 mm, respectively. We conclude that the proposed method can perform quantitative analysis of esophageal wall thickness and would be useful for tumor detection and tumor response evaluation of esophageal cancer.

  18. Detection of Cardiac Function Abnormality from MRI Images Using Normalized Wall Thickness Temporal Patterns.

    PubMed

    Wael, Mai; Ibrahim, El-Sayed H; Fahmy, Ahmed S

    2016-01-01

    Purpose. To develop a method for identifying abnormal myocardial function based on studying the normalized wall motion pattern during the cardiac cycle. Methods. The temporal pattern of the normalized myocardial wall thickness is used as a feature vector to assess the cardiac wall motion abnormality. Principal component analysis is used to reduce the feature dimensionality and the maximum likelihood method is used to differentiate between normal and abnormal features. The proposed method was applied on a dataset of 27 cases from normal subjects and patients. Results. The developed method achieved 81.5%, 85%, and 88.5% accuracy for identifying abnormal contractility in the basal, midventricular, and apical slices, respectively. Conclusions. A novel feature vector, namely, the normalized wall thickness, has been introduced for detecting myocardial regional wall motion abnormality. The proposed method provides assessment of the regional myocardial contractility for each cardiac segment and slice; therefore, it could be a valuable tool for automatic and fast determination of regional wall motion abnormality from conventional cine MRI images.

  19. Distribution of ice thickness and subglacial topography of the "Chinese Wall" around Kunlun Station, East Antarctica

    NASA Astrophysics Data System (ADS)

    Cui, Xiang-Bin; Sun, Bo; Su, Xiao-Gang; Guo, Jing-Xue

    2016-03-01

    As fundamental parameters of the Antarctic Ice Sheet, ice thickness and subglacial topography are critical factors for studying the basal conditions and mass balance in Antarctica. During CHINARE 24 (the 24th Chinese National Antarctic Research Expedition, 2007/08), the research team used a deep ice-penetrating radar system to measure the ice thickness and subglacial topography of the "Chinese Wall" around Kunlun Station, East Antarctica. Preliminary results show that the ice thickness varies mostly from 1600 m to 2800 m along the "Chinese Wall", with the thickest ice being 3444 m, and the thinnest ice 1255 m. The average bedrock elevation is 1722 m, while the minimum is just 604 m. Compared with the northern side of the ice divide, the ice thickness is a little greater and the subglacial topography lower on the southern side, which is also characterized by four deep valleys. We found no basal freeze-on ice in the Gamburtsev Subglacial Mountains area, subglacial lakes, or water bodies along the "Chinese Wall". Ice thickness and subglacial topography data extracted from the Bedmap 2 database along the "Chinese Wall" are consistent with our results, but their resolution and accuracy are very limited in areas where the bedrock fluctuates intensely. The distribution of ice thickness and subglacial topography detected by ice-penetrating radar clarifies the features of the ice sheet in this "inaccessible" region. These results will help to advance the study of ice sheet dynamics and the determination of future locations of the GSM's geological and deep ice core drilling sites in the Dome A region.

  20. Wall energy and wall thickness of exchange-coupled rare-earth transition-metal triple layer stacks

    SciTech Connect

    Raasch, D.; Mathieu, C.

    1997-08-01

    The room-temperature wall energy {sigma}{sub w}=4.0{times}10{sup {minus}3}J/m{sup 2} of an exchange-coupled Tb{sub 19.6}Fe{sub 74.7}Co{sub 5.7}/Dy{sub 28.5}Fe{sub 43.2}Co{sub 28.3} double layer stack can be reduced by introducing a soft magnetic intermediate layer in between both layers exhibiting a significantly smaller anisotropy compared to Tb{endash}FeCo and Dy{endash}FeCo. {sigma}{sub w} will decrease linearly with increasing intermediate layer thickness, d{sub IL}, until the wall is completely located within the intermediate layer for d{sub IL}{ge}d{sub w}, where d{sub w} denotes the wall thickness. Thus, d{sub w} can be obtained from the plot {sigma}{sub w} versus d{sub IL}. We determined {sigma}{sub w} and d{sub w} on Gd{endash}FeCo intermediate layers with different anisotropy behavior (perpendicular and in-plane easy axis) and compared the results with data obtained from Brillouin light-scattering measurements, where exchange stiffness, A, and uniaxial anisotropy, K{sub u}, could be determined. With the knowledge of A and K{sub u}, wall energy and thickness were calculated and showed an excellent agreement with the magnetic measurements. A ten times smaller perpendicular anisotropy of Gd{sub 28.1}Fe{sub 71.9} in comparison to Tb{endash}FeCo and Dy{endash}FeCo resulted in a much smaller {sigma}{sub w}=1.1{times}10{sup {minus}3}J/m{sup 2} and d{sub w}=24nm at 300 K. A Gd{sub 34.1}Fe{sub 61.4}Co{sub 4.5} with in-plane anisotropy at room temperature showed a further reduced {sigma}{sub w}=0.3{times}10{sup {minus}3}J/m{sup 2} and d{sub w}=17nm. The smaller wall energy was a result of a different wall structure compared to perpendicular layers. {copyright} {ital 1997 American Institute of Physics.}

  1. Aberration design of zoom lens systems using thick lens modules.

    PubMed

    Zhang, Jinkai; Chen, Xiaobo; Xi, Juntong; Wu, Zhuoqi

    2014-12-20

    A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval distances. All nine third-order aberrations of a thick lens component are considered during the design. The relationship of component aberrations in different zoom positions can be approximated from the aberration shift. After minimizing the aberrations of the zoom lens system, the nine third-order aberrations of every lens component can be determined. Then the thick lens structure of every lens component can be determined after optimization according to their first-order properties and third-order aberration targets. After a third optimization for minimum practical third-order aberrations of a zoom lens system, the aberration design using the thick lens module is complete, which provides a practical zoom lens system with thick lens structures. A double-sided telecentric zoom lens system is designed using the thick lens module in this paper, which shows that this method is practical for zoom lens design.

  2. Semi-automatic bowel wall thickness measurements on MR enterography in patients with Crohn's disease.

    PubMed

    Naziroglu, Robiel E; Puylaert, Carl A J; Tielbeek, Jeroen A W; Makanyanga, Jesica; Menys, Alex; Ponsioen, Cyriel Y; Hatzakis, Haralambos; Taylor, Stuart A; Stoker, Jaap; van Vliet, Lucas J; Vos, Frans M

    2017-06-01

    To evaluate a semi-automatic method for delineation of the bowel wall and measurement of the wall thickness in patients with Crohn's disease. 53 patients with suspected or proven Crohn's disease were selected. Two radiologists independently supervised the delineation of regions with active Crohn's disease on MRI, yielding manual annotations (Ano1, Ano2). Three observers manually measured the maximal bowel wall thickness of each annotated segment. An active contour segmentation approach semi-automatically delineated the bowel wall. For each active region, two segmentations (Seg1, Seg2) were obtained by independent observers, in which the maximum wall thickness was automatically determined. The overlap between (Seg1, Seg2) was compared with the overlap of (Ano1, Ano2) using Wilcoxon's signed rank test. The corresponding variances were compared using the Brown-Forsythe test. The variance of the semi-automatic thickness measurements was compared with the overall variance of manual measurements through an F-test. Furthermore, the intraclass correlation coefficient (ICC) of semi-automatic thickness measurements was compared with the ICC of manual measurements through a likelihood-ratio test. Patient demographics: median age, 30 years; interquartile range, 25-38 years; 33 females. The median overlap of the semi-automatic segmentations (Seg1 vs Seg2: 0.89) was significantly larger than the median overlap of the manual annotations (Ano1 vs Ano2: 0.72); p = 1.4 × 10(-5). The variance in overlap of the semi-automatic segmentations was significantly smaller than the variance in overlap of the manual annotations (p = 1.1 × 10(-9)). The variance of the semi-automated measurements (0.46 mm(2)) was significantly smaller than the variance of the manual measurements (2.90 mm(2), p = 1.1 × 10(-7)). The ICC of semi-automatic measurement (0.88) was significantly higher than the ICC of manual measurement (0.45); p = 0.005. The semi-automatic technique

  3. False positive reduction for wall thickness-based detection of colonic flat polyps via CT colonography

    NASA Astrophysics Data System (ADS)

    Pomeroy, Marc; Li, Lihong C.; Han, Hao; Wei, Xinzhou; Pickhardt, Perry J.; Liang, Zhengrong

    2017-03-01

    Computer-aided detection (CAD) of flat polyps, in contrast to other polyp types, is challenging due to their lack of projections from the colonic surface and limited geometrical features that can be extracted from such polyps. In this paper, we present a new approach for CAD of flat polyps via colon wall thickness mapping, texture feature extraction and analysis. First, we integrated our previous work of detecting flat polyp candidates via colon wall thickness mapping into this study for automated detection of initial polyp candidates (IPCs). The colon wall segmentation is established on a coupled level-set method after the lumen is electronically cleansed by a sophisticated statistical algorithm, which considers the partial volume effect to preserve the mucosa layer details. The IPC detection was performed based on the wall thickness local pattern. From each IPC volume, we extracted the 14 Haralick texture features and 16 additional features that were previously demonstrated to improve polyp classification performance. Then, we adopted the Rpackage "randomForest" to classify the features for false positive (FP) reduction. We evaluated our method via 16 patient datasets. The proposed scheme achieved a high capacity in terms of the well-known area under the curve value of 0.930. The FPs was reduced to less than 3 FPs/per polyp. The experiment results demonstrate the feasibility of our method in achieving computer aided detection of flat polyps, therefore, improving the screening capability of computed tomography cololongraphy.

  4. Effect of the thickness of flowable composite as intermediate layer to reduce microleakage on gingival wall

    NASA Astrophysics Data System (ADS)

    Natasha, V.; Suprastiwi, E.

    2017-08-01

    Microleakage of composite restoration in proximal composite restoration often occurs on the gingival wall. The purpose of this study is to evaluate the influence of flowable composite as an intermediate layer to reduce microleakage on the gingival wall. Thirty whole,extracted, upper premolars were divided into three groups. Within box-like cavities, the first group was restored with packable composite only. Group 2 was restored with flowable composite of a1mm thickness and then was restored with incrementally packable composite. Group 3 was restored similarly to group 2, however with a flowable composite thickness of 2mm. After thermocycling, the penetration of 1% methylene blue was investigated along the gingival wall. There were significant differences between group 1 and groups 2 and 3. No significant differences were found between groups 2 and 3. Flowable composite, as an intermediate layer, reduces microleakage of the gingival wall of proximal composite restorations. Nonetheless, the thickness of the flowable composite has no influence on the amount of microleakage observed.

  5. The effect of fig wall thickness in Ficus erecta var. beecheyana on parasitism

    NASA Astrophysics Data System (ADS)

    Tzeng, Hsy-Yu; Ou, Chern-Hsiung; Lu, Fu-Yuan; Bain, Anthony; Chou, Lien-Siang; Kjellberg, Finn

    2014-05-01

    Fig wasp communities constitute a model system to analyse determinants of community complexity and to investigate how biological interaction networks are maintained. It has been suggested for monoecious figs, that fig pollinating wasps avoid ovipositing in flowers located close to the fig wall because of strong parasitic pressure by wasps ovipositing through the fig wall. This behaviour could help explain why mainly seeds are produced in flowers located close to the fig wall, thus stabilizing the fig-pollinating wasp mutualism. In this contribution we explore, for dioecious figs, whether ovipositor length of parasitic species may really be limiting. In dioecious figs, functionally male figs produce pollinating wasps and pollen while female figs produce only seeds, facilitating selection of traits favouring pollinator reproduction in male figs. We show in Ficus erecta that fig walls are thicker in male figs than in female figs. Male figs presenting thick walls, thicker than the length of the parasites' ovipositors, went unparasitized while male figs presenting thinner walls were systematically parasitized. Hence, in F. erecta, ovipositor length of the parasites is limiting access to some figs. However, we also show that in another dioecious species, Ficus formosana, presenting thin walled male figs, no fig is protected against oviposition by its two parasites. Hence in dioecious as well as in monoecious figs, in some Ficus species, ovipositors of the parasites are limiting access to ovules, while in other Ficus species all ovules are exposed to parasitism.

  6. Novel MRI Technique Enables Non-Invasive Measurement of Atrial Wall Thickness.

    PubMed

    Varela, Marta; Morgan, Ross; Theron, Adeline; Dillon-Murphy, Desmond; Chubb, Henry; Whitaker, John; Henningsson, Markus; Aljabar, Paul; Schaeffter, Tobias; Kolbitsch, Christoph; Aslanidi, Oleg V

    2017-08-01

    Knowledge of atrial wall thickness (AWT) has the potential to provide important information for patient stratification and the planning of interventions in atrial arrhythmias. To date, information about AWT has only been acquired in post-mortem or poor-contrast computed tomography (CT) studies, providing limited coverage and highly variable estimates of AWT. We present a novel contrast agent-free MRI sequence for imaging AWT and use it to create personalized AWT maps and a biatrial atlas. A novel black-blood phase-sensitive inversion recovery protocol was used to image ten volunteers and, as proof of concept, two atrial fibrillation patients. Both atria were manually segmented to create subject-specific AWT maps using an average of nearest neighbors approach. These were then registered non-linearly to generate an AWT atlas. AWT was 2.4 ± 0.7 and 2.7 ± 0.7 mm in the left and right atria, respectively, in good agreement with post-mortem and CT data, where available. AWT was 2.6 ± 0.7 mm in the left atrium of a patient without structural heart disease, similar to that of volunteers. In a patient with structural heart disease, the AWT was increased to 3.1 ± 1.3 mm. We successfully designed an MRI protocol to non-invasively measure AWT and create the first whole-atria AWT atlas. The atlas can be used as a reference to study alterations in thickness caused by atrial pathology. The protocol can be used to acquire personalized AWT maps in a clinical setting and assist in the treatment of atrial arrhythmias.

  7. High Power Laser Beam Welding of Thick-walled Ferromagnetic Steels with Electromagnetic Weld Pool Support

    NASA Astrophysics Data System (ADS)

    Fritzsche, André; Avilov, Vjaceslav; Gumenyuk, Andrey; Hilgenberg, Kai; Rethmeier, Michael

    The development of modern high power laser systems allows single pass welding of thick-walled components with minimal distortion. Besides the high demands on the joint preparation, the hydrostatic pressure in the melt pool increases with higher plate thicknesses. Reaching or exceeding the Laplace pressure, drop-out or melt sagging are caused. A contactless electromagnetic weld support system was used for laser beam welding of thick ferromagnetic steel plates compensating these effects. An oscillating magnetic field induces eddy currents in the weld pool which generate Lorentz forces counteracting the gravity forces. Hysteresis effects of ferromagnetic steels are considered as well as the loss of magnetization in zones exceeding the Curie temperature. These phenomena reduce the effective Lorentz forces within the weld pool. The successful compensation of the hydrostatic pressure was demonstrated on up to 20 mm thick plates of duplex and mild steel by a variation of the electromagnetic power level and the oscillation frequency.

  8. Thickness and orientational design for a maximum stiff membrane

    NASA Technical Reports Server (NTRS)

    Pedersen, Pauli

    1990-01-01

    Recent results from sensitivity analysis for strain energy with anisotropic elasticity are applied to thickness and orientational design of laminated membranes. Primarily, the first order gradients of the total elastic energy are used in an optimality criteria based method. This traditional method is shown to give slow convergence with respect to design parameters, although the convergence of strain energy is very good. To get a deeper insight into this rather general characteristic, second order derivatives are included and it is shown how they can be obtained by first order sensitivity analysis. Examples of only thickness design, only orientational design, and combined thickness--orientational design are presented.

  9. Comparative physical and chemical analyses of cotton fibers from two near isogenic upland lines differing in fiber wall thickness

    USDA-ARS?s Scientific Manuscript database

    The thickness of cotton fiber cell walls is an important property that partially determines the economic value of cotton. To better understand the physical and chemical manifestations of the genetic variations that regulate the degree of fiber wall thickness, we used a comprehensive set of methods t...

  10. Correlation between capillary oxygen saturation and small intestinal wall thickness in the equine colic patient

    PubMed Central

    Mirle, Elisabeth; Wogatzki, Anna; Kunzmann, Robert; Schoenfelder, Axel M; Litzke, Lutz F

    2017-01-01

    The surgical evaluation of haemorrhagic infarcted intestine and the decision for or against bowel resection require a lot of experience and are subjective. The aim of this prospective, clinical study was to examine the correlation between oxygen saturation and small intestinal wall (IW) thickness, using two objective methods. In 22 colicky horses, the blood flow, oxygen saturation and relative amount of haemoglobin were measured intraoperatively via laser Doppler and white light spectroscopy (O2C, oxygen to see, LEA Medizintechnik) at six measuring points (MPs) in small and large intestines. Furthermore, the IW thickness was measured ultrasonographically. Nine of 22 horses had an increased small IW thickness greater than 4 mm (Freeman 2002, Scharner and others 2002, le Jeune and Whitcomb 2014) at measuring point 1 (MP1) (strangulated segment), four horses had a thickened bowel wall at measuring point 3 (MP3) (poststenotic) and one at measuring point 2 (MP2). The oxygen saturation was 0 at MP1 in six horses, at MP3 in two horses and at MP2 (prestenotic) in one. Oxygen saturation and small IW thickness were independent of each other at MP1 and MP2. At MP3, the two parameters were negatively correlated. In summary, it is not possible to draw conclusions about oxygen saturation based on IW thickness. PMID:28761667

  11. Correlation between capillary oxygen saturation and small intestinal wall thickness in the equine colic patient.

    PubMed

    Mirle, Elisabeth; Wogatzki, Anna; Kunzmann, Robert; Schoenfelder, Axel M; Litzke, Lutz F

    2017-01-01

    The surgical evaluation of haemorrhagic infarcted intestine and the decision for or against bowel resection require a lot of experience and are subjective. The aim of this prospective, clinical study was to examine the correlation between oxygen saturation and small intestinal wall (IW) thickness, using two objective methods. In 22 colicky horses, the blood flow, oxygen saturation and relative amount of haemoglobin were measured intraoperatively via laser Doppler and white light spectroscopy (O2C, oxygen to see, LEA Medizintechnik) at six measuring points (MPs) in small and large intestines. Furthermore, the IW thickness was measured ultrasonographically. Nine of 22 horses had an increased small IW thickness greater than 4 mm (Freeman 2002, Scharner and others 2002, le Jeune and Whitcomb 2014) at measuring point 1 (MP1) (strangulated segment), four horses had a thickened bowel wall at measuring point 3 (MP3) (poststenotic) and one at measuring point 2 (MP2). The oxygen saturation was 0 at MP1 in six horses, at MP3 in two horses and at MP2 (prestenotic) in one. Oxygen saturation and small IW thickness were independent of each other at MP1 and MP2. At MP3, the two parameters were negatively correlated. In summary, it is not possible to draw conclusions about oxygen saturation based on IW thickness.

  12. Gastric Wall Thickness and the Choice of Linear Staples in Laparoscopic Sleeve Gastrectomy: Challenging Conventional Concepts.

    PubMed

    Abu-Ghanem, Yasmin; Meydan, Chanan; Segev, Lior; Rubin, Moshe; Blumenfeld, Orit; Spivak, Hadar

    2017-03-01

    Little evidence is available on the choice of linear staple reloads in laparoscopic sleeve gastrectomy (LSG). Previous literature recommends matching closed staple height (CSH) to tissue-thickness (TT) to avoid ischemia. Our objective was to examine feasibility and safety of "tight" hemostatic (CSH/TT <1) stapling and map the entire gastric wall TT in LSG patients. Prospectively collected outcomes on 202 consecutive patients who underwent LSG with tight order of staples (Ethicon Endosurgery) in this order: pre-pylorus-black (CSH = 2.3 mm), antrum-green (CSH = 2.0 mm), antrum/body-blue (CSH = 1.5 mm), and white (CSH = 1.0 mm) on the body and fundus. Measurements of entire gastric wall TT were made on the first 100 patients' gastric specimens with an electronic-dogmatic indicator. Study included 147 females and 55 males with a mean age of 41.5 ± 11.9 years and body mass index of 41.5 ± 3.8 kg/m(2). Gastric wall measurements revealed mean CSH/TT ratio <1, decreasing from 0.7 ± 0.1 at pre-pylorus to 0.5 ± 0.1 at the fundus. There were 3.1% mechanical failures, mainly (68%) at pre-pylorus-black reloads. Post-operative bleeding occurred in 5 (2.5%) patients. There were no leaks or clinical evidence of sleeve ischemia. Stepwise regression analysis revealed that body mass index (P < 0.001), hypertension (P < 0.01), and male gender (P < 0.001) were associated with increased gastric TT. Our study suggests that reloads with CSH/TT <1 in LSG including staples with CSH of 1 mm on body and fundus are safe. The results challenge the concept that tight stapling cause's ischemia. Since tight reloads are designed to improve hemostasis, their application could have clinical benefit.

  13. The thick left ventricular wall of the giraffe heart normalises wall tension, but limits stroke volume and cardiac output.

    PubMed

    Smerup, Morten; Damkjær, Mads; Brøndum, Emil; Baandrup, Ulrik T; Kristiansen, Steen Buus; Nygaard, Hans; Funder, Jonas; Aalkjær, Christian; Sauer, Cathrine; Buchanan, Rasmus; Bertelsen, Mads Frost; Østergaard, Kristine; Grøndahl, Carsten; Candy, Geoffrey; Hasenkam, J Michael; Secher, Niels H; Bie, Peter; Wang, Tobias

    2016-02-01

    Giraffes--the tallest extant animals on Earth--are renowned for their high central arterial blood pressure, which is necessary to secure brain perfusion. Arterial pressure may exceed 300 mmHg and has historically been attributed to an exceptionally large heart. Recently, this has been refuted by several studies demonstrating that the mass of giraffe heart is similar to that of other mammals when expressed relative to body mass. It thus remains unexplained how the normal-sized giraffe heart generates such massive arterial pressures. We hypothesized that giraffe hearts have a small intraventricular cavity and a relatively thick ventricular wall, allowing for generation of high arterial pressures at normal left ventricular wall tension. In nine anaesthetized giraffes (495±38 kg), we determined in vivo ventricular dimensions using echocardiography along with intraventricular and aortic pressures to calculate left ventricular wall stress. Cardiac output was also determined by inert gas rebreathing to provide an additional and independent estimate of stroke volume. Echocardiography and inert gas-rebreathing yielded similar cardiac outputs of 16.1±2.5 and 16.4±1.4 l min(-1), respectively. End-diastolic and end-systolic volumes were 521±61 ml and 228±42 ml, respectively, yielding an ejection fraction of 56±4% and a stroke volume of 0.59 ml kg(-1). Left ventricular circumferential wall stress was 7.83±1.76 kPa. We conclude that, relative to body mass, a small left ventricular cavity and a low stroke volume characterizes the giraffe heart. The adaptations result in typical mammalian left ventricular wall tensions, but produce a lowered cardiac output.

  14. Simulation on the Effect of Bottle Wall Thickness Distribution using Blow Moulding Technique

    NASA Astrophysics Data System (ADS)

    Suraya, S.; Azman, M. D.; Fatchurrohman, N.; Jaafar, A. A.; Yusoff, A. R.

    2016-02-01

    The aims of this study are to assess the deformation behavior of a polymeric material during a blow moulding process. Transient computations of two dimensional model of a PP bottle were performed using ANSYS Polyflow computer code to predict the wall thickness distribution at four different parison's diameter; 8mm, 10mm, 18mm, and 20mm. Effects on the final wall thickness diameter and time step are studied. The simulated data shows that the inflation performance degrades with increasing parison diameter. It is concluded that the blow moulding process using 10mm parison successfully meet the product processing requirements. Factors that contribute to the variation in deformation behaviour of the plastic during the manufacturing process are discussed.

  15. Separation occurring during the drop weight tear test of thick-walled X80 pipeline steels

    NASA Astrophysics Data System (ADS)

    Sha, Qing-yun; Li, Da-hang; Huang, Guo-jian; Guan, Ju

    2013-08-01

    A separation phenomenon occurring during the drop weight tear test of commercial thick-walled API (American Petroleum Institute) X80 strip steel was investigated in this work. Microstructural analysis showed that the band structure of bainite elongated along the rolling direction works as the initiation sites of separation. The propagation of separation can be promoted not only by the occurrence of the band structure of martensite/austenite constituent, prior austenite grain boundaries, and elongated bainite, but also by fine acicular ferrite and bainite. Wide separation formed in the former case, while the narrow one appeared in the latter case. Some methods were proposed to obtain fine and homogeneous acicular ferrite in thick-walled X80 pipeline steel in order to minimize the occurrence of separation.

  16. A thermoelastic transversely isotropic thick walled cylinder/disk application: An analytical solution and study

    NASA Technical Reports Server (NTRS)

    Arnold, S. M.

    1989-01-01

    A continuum theory is utilized to represent the thermoelastic behavior of a thick walled composite cylinder that can be idealized as transversely isotropic. A multiaxial statement of the constitutive theory employed is presented, as well as the out of the plane of isotropy, plane stress, and plane strain reductions. The derived analytical solution presented is valid for a cylindrical tube or thin disk with a concentric hole, subjected to internal and/or external pressure and a general radial temperature distribution. A specific problem examined is that of a thick walled cylinder subjected to an internal and external pressure loading and a linear radial temperature distribution. The results are expressed in nondimensional form and the effects on the response behavior are examined for various material properties, fiber orientation and types of loadings.

  17. Remodeling of blood vessels: responses of diameter and wall thickness to hemodynamic and metabolic stimuli.

    PubMed

    Pries, Axel R; Reglin, Bettina; Secomb, Timothy W

    2005-10-01

    Vascular functions, including tissue perfusion and peripheral resistance, reflect continuous structural adaptation (remodeling) of blood vessels in response to several stimuli. Here, a theoretical model is presented that relates the structural and functional properties of microvascular networks to the adaptive responses of individual segments to hemodynamic and metabolic stimuli. All vessels are assumed to respond, according to a common set of adaptation rules, to changes in wall shear stress, circumferential wall stress, and tissue metabolic status (indicated by partial pressure of oxygen). An increase in vessel diameter with increasing wall shear stress and an increase in wall mass with increased circumferential stress are needed to ensure stable vascular adaptation. The model allows quantitative predictions of the effects of changes in systemic hemodynamic conditions or local adaptation characteristics on vessel structure and on peripheral resistance. Predicted effects of driving pressure on the ratio of wall thickness to vessel diameter are consistent with experimental observations. In addition, peripheral resistance increases by approximately 65% for an increase in driving pressure from 50 to 150 mm Hg. Peripheral resistance is predicted to be markedly increased in response to a decrease in vascular sensitivity to wall shear stress, and to be decreased in response to increased tissue metabolic demand. This theoretical approach provides a framework for integrating available information on structural remodeling in the vascular system and predicting responses to changing conditions or altered vascular reactivity, as may occur in hypertension.

  18. The Measurement and Analysis of Fatigue Crack Growth in Thick-Walled Cylinders

    DTIC Science & Technology

    1974-09-01

    NAME AND ADDRESS Benet Weapons laboratory Watervliet Arsenal, Watervliet, N.Y . 12189 SARWV-RDT 11 CONTF>OLLING O FFI CE NA~E AND ADDRESS 5. TYPE...depth in thick-walled cylinders using a straight-beam ultrasonic probe. This technique has proved useful not only under laboratory conditions, but...R. R. FUJCZAK BENET WEAPONS LABORATORY WATERVLIET ARSENAL WATERVLIET. N.Y. 12189 SEPTEMBER 1974 TECHNICAL REPORT AMCMS No. 5596.OM.6350

  19. Stress Intensity Factors for Radial Cracks in a Partially Autofrettaged Thick-Wall Cylinder

    DTIC Science & Technology

    1981-07-01

    P., "Simulation of Partial Autofrettage by Thermal Loads," Journal of Pressure Vessel Technology, Vol. 102, No. 3, 1980, pp. 314-318. ^ Baratta , F...OF LOAD RELIEF FACTOR Baratta ^ extended the coefficient of load relief of Neuber^^ to estimate SIF arising from multiple cracking in a thick-wall...Array Radial Cracks Using Isoparametric Singular Elements," ASTM STP-677, 1979, pp. 685-699. ■^ Baratta , F. I., "Stress Intensity Factors For

  20. COANDA Control of a Thick Wall-Jet in the Static Case

    DTIC Science & Technology

    1982-11-01

    downward (and in some cases more than 90 degrees downward, producing thrust reversal) when the CC Coanda jet is activated. Experimental research was...conforming to its shape ( Coanda effect) and induces upstream air on the upper c surface to follow the jet flow. This phenomenon effectively increases the...ro.r.d~d trailing edge. r Thikcxtes5 of the Coanda jet, It Entrainnment length--the distance between the exit plane of the thick " wall-jet nozzle and

  1. A comparative assessment of the wall thickness margin taking into account the initial flaws in steam line elements

    NASA Astrophysics Data System (ADS)

    Gladshtein, V. I.

    2011-02-01

    A procedure for estimating the wall thickness margin for operation during a specified design service life under creep conditions if the metal of articles contains initial flaws is presented. The analysis is carried out taking as an example parts of steam lines made of two different grades of steel: a cast elbow with the size d = 426 × 30 mm made of 15Kh1M1FL low-alloy steel and a pipe bend with the size d = 219 × 32 mm made of EI-756 12% chromium steel. The calculated assessments are compared with the results obtained from long-term operation.

  2. Left ventricular posterior wall thickness is an independent risk factor for paroxysmal atrial fibrillation.

    PubMed

    Xu, H F; He, Y M; Qian, Y X; Zhao, X; Li, X; Yang, X J

    2011-12-01

    Atrial fibrillation is the most common significant cardiac arrhythmia in clinical practice, but its risk factors remain to be clarified. We have hypothesized that left ventricular posterior wall thickness is an independent risk factor for paroxysmal atrial fibrillation (PAF). A total of 166 consecutive patients with paroxysmal atrial fibrillation were included in this study. Another 166 healthy check-up people, strictly age and sex-matched, were enrolled as controls in the same period. Univariable analysis and multivariable conditional logistic stepwise regression analysis were conducted. Receiver operating characteristic (ROC) curve analysis was performed on those significant indices obtained from the multivariable logistic regression analysis. The multivariable stepwise analysis identified left ventricular posterior wall thickness, left atrial diameter tricuspid insufficiency and residence (countryside) as independent predictors for paroxysmal atrial fibrillation. Receiver operating characteristic curve analysis demonstrated the cutoff values of those risk factors aforementioned. In this strictly age and sex-matched population-based sample, left ventricular posterior wall thickness, left atrial diameter, tricuspid insufficiency and residence were predictive risks for paroxysmal atrial fibrillation. This study offers novel information therapeutically beyond that provided by traditional clinical atrial fibrillation risk factors.

  3. Carotid wall stress calculated with continuous intima-media thickness assessment using B-mode ultrasound

    NASA Astrophysics Data System (ADS)

    Pascaner, A. F.; Craiem, D.; Casciaro, M. E.; Danielo, R.; Graf, S.; Guevara, E.

    2016-04-01

    Cardiovascular risk is normally assessed using clinical risk factors but it can be refined using non-invasive infra-clinical markers. Intima-Media Thickness (IMT) is recognized as an early indicator of cardiovascular disease. Carotid Wall Stress (CWS) can be calculated using arterial pressure and carotid size (diameter and IMT). Generally, IMT is measured during diastole when it reaches its maximum value. However, it changes during the cardiac cycle and a time-dependant waveform can be obtained using B-mode ultrasound images. In this work we calculated CWS considering three different approaches for IMT assessment: (i) constant IMT (standard diastolic value), (ii) estimated IMT from diameter waveform (assuming a constant cross-sectional wall area) and (iii) continuously measured IMT. Our results showed that maximum wall stress depends on the IMT estimation method. Systolic CWS progressively increased using the three approaches (p<0.024). We conclude that maximum CWS is highly dependent on wall thickness and accurate IMT measures during systole should be encouraged.

  4. Detection of colonic polyp candidates with level set-based thickness mapping over the colon wall

    NASA Astrophysics Data System (ADS)

    Han, Hao; Li, Lihong; Duan, Chaijie; Zhao, Yang; Wang, Huafeng; Liang, Zhengrong

    2015-03-01

    Further improvement of computer-aided detection (CADe) of colonic polyps is vital to advance computed tomographic colonography (CTC) toward a screening modality, where the detection of flat polyps is especially challenging because limited image features can be extracted from flat polyps, and the traditional geometric features-based CADe methods usually fail to detect such polyps. In this paper, we present a novel pipeline to automatically detect initial polyp candidates (IPCs), especially flat polyps, from CTC images. First, the colon wall mucosa was extracted via a partial volume segmentation approach as a volumetric layer, where the inner border of colon wall can be obtained by shrinking the volumetric layer using level set based adaptive convolution. Then the outer border of colon wall (or the colon wall serosa) was segmented via a combined implementation of geodesic active contour and Mumford-Shah functional in a coarse-to-fine manner. Finally, the wall thickness was estimated along a unique path between the segmented inner and outer borders with consideration of the volumetric layers and was mapped onto a patient-specific three-dimensional (3D) colon wall model. The IPC detection results can usually be better visualized in a 2D image flattened from the 3D model, where abnormalities were detected by Z-score transformation of the thickness values. The proposed IPC detection approach was validated on 11 patients with 22 CTC scans, and each scan has at least one flat poly annotation. The above presented novel pipeline was effective to detect some flat polyps that were missed by our CADe system while keeping false detections in a relative low level. This preliminary study indicates that the presented pipeline can be incorporated into an existing CADe system to enhance the polyp detection power, especially for flat polyps.

  5. Transabdominal ultrasound for standardized measurement of bowel wall thickness in normal children and those with Crohn's disease.

    PubMed

    Chiorean, Liliana; Schreiber-Dietrich, Dagmar; Braden, Barbara; Cui, XinWu; Dietrich, Christoph F

    2014-12-01

    The intestinal wall can be visualized using high resolution transabdominal ultrasound (TUS). TTUS measurement of the bowel wall thickness has been described in adults but data are lacking in children. The purpose of this prospective study was to sonographically investigate bowel wall thickness in healthy children and children with Crohn's disease. TUS (5-15 MHz) of the intestine was performed in 58 healthy children (age range 3 to 16 years) and in 30 children with Crohn's disease (age range 8 to 17 years). The following regions were assessed and bowel wall thickness measured: terminal ileum, cecum, right flexure, and sigmoid colon. In patients with Crohn's disease, the involved region was additionally assessed regarding length of involved segment and sonographic signs of transmural inflammation and fistula. TUS allowed adequate measurement of bowel wall thickness in all 58 healthy children (100%) and in all 30 Crohn's disease patients (100%). The bowel wall thickness significantly differed between groups. Bowel wall thickness (mean +/- SD) in all segments was less then 2 mm in all healthy children (1.0+/-0.1 mm terminal ileum, 1.1+/-0.1 mm cecum, 1.1+/-0.1 mm right flexure, and 1.3+/-0.1 mm sigmoid colon). In Crohn's disease patients, bowel wall thickness was ≥ 3 mm in the ileocecal region and was significantly increased (5.1+/-1.9 mm) compared to the healthy children. The mean length of involved segment was 15+/-6.5 cm [5 - 30 cm]. Additional findings in Crohn's disease patients were: transmural inflamation (3/30), interenteric fistula (3/30), gastrocolic fistula (1/30) and vesicoenteric fistula (1/30). Similar to adults, normal bowel wall thickness in children is always less than 2 mm. In all patients with Crohn's disease, increased bowel wall thickness could be detected. TUS is a helpful tool in the diagnosis and assessment of activity and complications in Crohn's disease.

  6. A Review of Thermal Conductivity of Polymer Matrix Syntactic Foams—Effect of Hollow Particle Wall Thickness and Volume Fraction

    NASA Astrophysics Data System (ADS)

    Gupta, Nikhil; Pinisetty, Dinesh

    2013-02-01

    Hollow-particle-filled composites called syntactic foams are lightweight particulate composites that are useful in weight-sensitive applications such as aerospace and marine structures. Extensive literature is now available on the mechanical properties of syntactic foams. The upcoming applications for syntactic foams in aerospace structures require understanding of their thermal properties, such as the thermal conductivity. The present review article summarizes the available experimental results and theoretical models related to the thermal conductivity of syntactic foams. Experimental results are available for only a few compositions of syntactic foams. Basic understating of the relationship between thermal conductivity of syntactic foams and the material parameters, such as hollow particle volume fraction and wall thickness, is not available through experimental results at this point. Four theoretical models are tested with the experimental data and found to provide close predictions. These models are used to conduct parametric studies. It is observed that the thermal conductivity of syntactic foams decreases as the volume fraction of thin-walled particles is increased. An inverse relationship is observed for thick-walled, hollow-particle-filled syntactic foams. These models can help in designing syntactic foams with required thermal conductivity.

  7. Measure Guideline: Incorporating Thick Layers of Exterior Rigid Insulation on Walls

    SciTech Connect

    Lstiburek, Joseph; Baker, Peter

    2015-04-01

    This measure guideline provides information about the design and construction of wall assemblies that use layers of rigid exterior insulation thicker than 1-½ inches and that require a secondary cladding attachment location exterior to the insulation. The guideline is separated into several distinct sections that cover: fundamental building science principles relating to the use of exterior insulation on wall assemblies; design principles for tailoring this use to the specific project goals and requirements; and construction detailing to increase understanding about implementing the various design elements.

  8. Measure Guideline. Incorporating Thick Layers of Exterior Rigid Insulation on Walls

    SciTech Connect

    Lstiburek, Joseph; Baker, Peter

    2015-04-09

    This measure guideline, written by the U.S. Department of Energy’s Building America team Building Science Corporation, provides information about the design and construction of wall assemblies that use layers of rigid exterior insulation thicker than 1-½ in. and that require a secondary cladding attachment location exterior to the insulation. The guideline is separated into several distinct sections that cover: (1) fundamental building science principles relating to the use of exterior insulation on wall assemblies; (2) design principles for tailoring this use to the specific project goals and requirements; and (3) construction detailing to increase understanding about implementing the various design elements.

  9. Importance of head diameter, clearance, and cup wall thickness in elastohydrodynamic lubrication analysis of metal-on-metal hip resurfacing prostheses.

    PubMed

    Liu, Feng; Jin, Zhongmin; Roberts, P; Grigoris, P

    2006-08-01

    The main design features of metal-on-metal (MOM) hip resurfacing prostheses in promoting elastohydrodynamic lubrication were investigated in the present study, including the femoral head diameter, the clearance, and the cup wall thickness. Simplified conceptual models were developed, based on equivalent uniform wall thicknesses for both the cup and the head as well as the support materials representing bone and cement, and subsequently used for elastohydrodynamic lubrication analysis. Both typical first- and second-generation MOM hip resurfacing prostheses with different clearances and cup wall thicknesses were considered with a fixed large bearing diameter of 50 mm, as well as a 28 mm diameter MOM total hip replacement bearing for the purpose of comparison. The importance of the head diameter and the clearance in promoting elastohydrodynamic lubrication was confirmed. Furthermore, it was also predicted that a relatively thin acetabular cup in the more recently introduced second-generation MOM hip resurfacing prostheses would be capable of improving elastohydrodynamic lubrication even further.

  10. Development of automated welding process for field fabrication of thick walled pressure vessels. Fourth quarter technical progress report for period ending September 28, 1980

    SciTech Connect

    Not Available

    1980-01-01

    Progress is reported in research aimed at optimizing an automated welding process for the field fabrication of thick-walled pressure vessels and for evaluating the welded joints. Information is included on the welding equipment, mechanical control of the process, joint design, filler wire optimization, in-process nondestructive testing of welds, and repair techniques. (LCL)

  11. Accurate measurement of respiratory airway wall thickness in CT images using a signal restoration technique

    NASA Astrophysics Data System (ADS)

    Park, Sang Joon; Kim, Tae Jung; Kim, Kwang Gi; Lee, Sang Ho; Goo, Jin Mo; Kim, Jong Hyo

    2008-03-01

    Airway wall thickness (AWT) is an important bio-marker for evaluation of pulmonary diseases such as chronic bronchitis, bronchiectasis. While an image-based analysis of the airway tree can provide precise and valuable airway size information, quantitative measurement of AWT in Multidetector-Row Computed Tomography (MDCT) images involves various sources of error and uncertainty. So we have developed an accurate AWT measurement technique for small airways with three-dimensional (3-D) approach. To evaluate performance of these techniques, we used a set of acryl tube phantom was made to mimic small airways to have three different sizes of wall diameter (4.20, 1.79, 1.24 mm) and wall thickness (1.84, 1.22, 0.67 mm). The phantom was imaged with MDCT using standard reconstruction kernel (Sensation 16, Siemens, Erlangen). The pixel size was 0.488 mm × 0.488 mm × 0.75 mm in x, y, and z direction respectively. The images were magnified in 5 times using cubic B-spline interpolation, and line profiles were obtained for each tube. To recover faithful line profile from the blurred images, the line profiles were deconvolved with a point spread kernel of the MDCT which was estimated using the ideal tube profile and image line profile. The inner diameter, outer diameter, and wall thickness of each tube were obtained with full-width-half-maximum (FWHM) method for the line profiles before and after deconvolution processing. Results show that significant improvement was achieved over the conventional FWHM method in the measurement of AWT.

  12. New research perspectives from a novel approach to quantify tracheid wall thickness.

    PubMed

    Prendin, Angela Luisa; Petit, Giai; Carrer, Marco; Fonti, Patrick; Björklund, Jesper; von Arx, Georg

    2017-07-01

    The analysis of xylem cell anatomical features in dated tree rings provides insights into xylem functional responses and past growth conditions at intra-annual resolution. So far, special focus has been given to the lumen of the water-conducting cells, whereas the equally relevant cell wall thickness (CWT) has been less investigated due to methodological limitations. Here we present a novel approach to measure tracheid CWT in high-resolution images of wood cross-sections that is implemented within the specialized image-analysis tool 'ROXAS'. Compared with the traditional manual line measurements along a selection of few radial files, this novel image-analysis tool can: (i) measure CWT of all tracheids in a tree-ring cross-section, thus increasing the number of individual tracheid measurements by a factor of ~10-20; (ii) measure the tangential and radial walls separately; and (iii) laterally integrate the measurements in a customizable way from only the thinnest central part of the cell walls up to the thickest part of the tracheids at the corners. Cell wall thickness measurements performed with our novel approach and the traditional manual approach showed comparable accuracy for several image resolutions, with an optimal accuracy-efficiency balance at 100× magnification. The configurable settings intended to underscore different cell wall properties indeed changed the absolute levels and intra- and inter-annual patterns of CWT. This versatility, together with the high data production capacity, allows to tailor the measurements of CWT to the specific goal of each study, which opens new research perspectives, e.g., for investigating structure-function relationships, tree stress responses and carbon allocation patterns, and for reconstructing climate based on intra- and inter-annual variability of anatomical wood density. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Growth and Remodeling in a Thick-Walled Artery Model: Effects of Spatial Variations in Wall Constituents

    PubMed Central

    Alford, Patrick W.; Humphrey, Jay D.; Taber, Larry A.

    2008-01-01

    A mathematical model is presented for growth and remodeling of arteries. The model is a thick-walled tube composed of a constrained mixture of smooth muscle cells, elastin and collagen. Material properties and radial and axial distributions of each constituent are prescribed according to previously published data. The analysis includes stress-dependent growth and contractility of the muscle and turnover of collagen fibers. Simulations were conducted for homeostatic conditions and for the temporal response following sudden hypertension. Numerical pressure-radius relations and opening angles (residual stress) show reasonable agreement with published experimental results. In particular, for realistic material and structural properties, the model predicts measured variations in opening angles along the length of the aorta with reasonable accuracy. These results provide a better understanding of the determinants of residual stress in arteries and could lend insight into the importance of constituent distributions in both natural and tissue-engineered blood vessels. PMID:17786493

  14. The effect of wall thickness distribution on mechanical reliability and strength in unidirectional porous ceramics.

    PubMed

    Seuba, Jordi; Deville, Sylvain; Guizard, Christian; Stevenson, Adam J

    2016-01-01

    Macroporous ceramics exhibit an intrinsic strength variability caused by the random distribution of defects in their structure. However, the precise role of microstructural features, other than pore volume, on reliability is still unknown. Here, we analyze the applicability of the Weibull analysis to unidirectional macroporous yttria-stabilized-zirconia (YSZ) prepared by ice-templating. First, we performed crush tests on samples with controlled microstructural features with the loading direction parallel to the porosity. The compressive strength data were fitted using two different fitting techniques, ordinary least squares and Bayesian Markov Chain Monte Carlo, to evaluate whether Weibull statistics are an adequate descriptor of the strength distribution. The statistical descriptors indicated that the strength data are well described by the Weibull statistical approach, for both fitting methods used. Furthermore, we assess the effect of different microstructural features (volume, size, densification of the walls, and morphology) on Weibull modulus and strength. We found that the key microstructural parameter controlling reliability is wall thickness. In contrast, pore volume is the main parameter controlling the strength. The highest Weibull modulus ([Formula: see text]) and mean strength (198.2 MPa) were obtained for the samples with the smallest and narrowest wall thickness distribution (3.1 [Formula: see text]m) and lower pore volume (54.5%).

  15. The effect of wall thickness distribution on mechanical reliability and strength in unidirectional porous ceramics

    PubMed Central

    Seuba, Jordi; Deville, Sylvain; Guizard, Christian; Stevenson, Adam J.

    2016-01-01

    Macroporous ceramics exhibit an intrinsic strength variability caused by the random distribution of defects in their structure. However, the precise role of microstructural features, other than pore volume, on reliability is still unknown. Here, we analyze the applicability of the Weibull analysis to unidirectional macroporous yttria-stabilized-zirconia (YSZ) prepared by ice-templating. First, we performed crush tests on samples with controlled microstructural features with the loading direction parallel to the porosity. The compressive strength data were fitted using two different fitting techniques, ordinary least squares and Bayesian Markov Chain Monte Carlo, to evaluate whether Weibull statistics are an adequate descriptor of the strength distribution. The statistical descriptors indicated that the strength data are well described by the Weibull statistical approach, for both fitting methods used. Furthermore, we assess the effect of different microstructural features (volume, size, densification of the walls, and morphology) on Weibull modulus and strength. We found that the key microstructural parameter controlling reliability is wall thickness. In contrast, pore volume is the main parameter controlling the strength. The highest Weibull modulus (m=13.2) and mean strength (198.2 MPa) were obtained for the samples with the smallest and narrowest wall thickness distribution (3.1 μm) and lower pore volume (54.5%). PMID:27877864

  16. Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines

    PubMed Central

    Tuck, Jeffrey; Lee, Pedro

    2013-01-01

    Analysis of transient fluid pressure signals has been investigated as an alternative method of fault detection in pipeline systems and has shown promise in both laboratory and field trials. The advantage of the method is that it can potentially provide a fast and cost effective means of locating faults such as leaks, blockages and pipeline wall degradation within a pipeline while the system remains fully operational. The only requirement is that high speed pressure sensors are placed in contact with the fluid. Further development of the method requires detailed numerical models and enhanced understanding of transient flow within a pipeline where variations in pipeline condition and geometry occur. One such variation commonly encountered is the degradation or thinning of pipe walls, which can increase the susceptible of a pipeline to leak development. This paper aims to improve transient-based fault detection methods by investigating how changes in pipe wall thickness will affect the transient behaviour of a system; this is done through the analysis of laboratory experiments. The laboratory experiments are carried out on a stainless steel pipeline of constant outside diameter, into which a pipe section of variable wall thickness is inserted. In order to detect the location and severity of these changes in wall conditions within the laboratory system an inverse transient analysis procedure is employed which considers independent variations in wavespeed and diameter. Inverse transient analyses are carried out using a genetic algorithm optimisation routine to match the response from a one-dimensional method of characteristics transient model to the experimental time domain pressure responses. The accuracy of the detection technique is evaluated and benefits associated with various simplifying assumptions and simulation run times are investigated. It is found that for the case investigated, changes in the wavespeed and nominal diameter of the pipeline are both important

  17. Collapse Pressure Analysis of Transversely Isotropic Thick-Walled Cylinder Using Lebesgue Strain Measure and Transition Theory

    PubMed Central

    Aggarwal, A. K.; Sharma, Richa; Sharma, Sanjeev

    2014-01-01

    The objective of this paper is to provide guidance for the design of the thick-walled cylinder made up of transversely isotropic material so that collapse of cylinder due to influence of internal and external pressure can be avoided. The concept of transition theory based on Lebesgue strain measure has been used to simplify the constitutive equations. Results have been analyzed theoretically and discussed numerically. From this analysis, it has been concluded that, under the influence of internal and external pressure, circular cylinder made up of transversely isotropic material (beryl) is on the safer side of the design as compared to the cylinders made up of isotropic material (steel). This is because of the reason that percentage increase in effective pressure required for initial yielding to become fully plastic is high for beryl as compared to steel which leads to the idea of “stress saving” that reduces the possibility of collapse of thick-walled cylinder due to internal and external pressure. PMID:24523632

  18. Controlled protein release from monodisperse biodegradable double-wall microspheres of controllable shell thickness

    PubMed Central

    Xia, Yujie; Ribeiro, Pedro F.; Pack, Daniel W.

    2013-01-01

    Biodegradable polymer microparticles are promising delivery depots for protein therapeutics due to their relatively simple fabrication and facile administration. Double-wall microspheres (DWMS) comprising a core and shell made of two distinct polymers may provide enhanced control of the drug release profiles. Using precision particle fabrication (PPF) technology, monodisperse DWMS were fabricated with model protein bovine serum albumin (BSA)-loaded poly(lactide-co-glycolide) (PLG) core and drug-free poly(d,l-lactic acid) (PDLL) shell of uniform thickness. Monolithic single-wall microspheres were also fabricated to mimic the BSA-loaded PLG core. Using ethyl acetate and dichloromethane as shell- and core-phase solvents, respectively, BSA was encapsulated selectively in the core region within DWMS with higher loading and encapsulation efficiency compared to using dichloromethane as core and shell solvents. BSA in vitro release rates were retarded by the presence of the drug-free PDLL shell. Moreover, increasing PDLL shell thickness resulted in decreasing BSA release rate. With a 14-µm thick PDLL shell, an extended period of constant-rate release was achieved. PMID:23954731

  19. Extremely thick cell walls and low mesophyll conductance: welcome to the world of ancient living!

    PubMed Central

    Tosens, Tiina; Laanisto, Lauri; Niinemets, Ülo

    2017-01-01

    Abstract Mesophyll conductance is thought to be an important photosynthetic limitation in gymnosperms, but they currently constitute the most understudied plant group in regard to the extent to which photosynthesis and intrinsic water use efficiency are limited by mesophyll conductance. A comprehensive analysis of leaf gas exchange, photosynthetic limitations, mesophyll conductance (calculated by three methods previously used for across-species comparisons), and the underlying ultra-anatomical, morphological and chemical traits in 11 gymnosperm species varying in evolutionary history was performed to gain insight into the evolution of structural and physiological controls on photosynthesis at the lower return end of the leaf economics spectrum. Two primitive herbaceous species were included in order to provide greater evolutionary context. Low mesophyll conductance was the main limiting factor of photosynthesis in the majority of species. The strongest sources of limitation were extremely thick mesophyll cell walls, high chloroplast thickness and variation in chloroplast shape and size, and the low exposed surface area of chloroplasts per unit leaf area. In gymnosperms, the negative relationship between net assimilation per mass and leaf mass per area reflected an increased mesophyll cell wall thickness, whereas the easy-to-measure integrative trait of leaf mass per area failed to predict the underlying ultrastructural traits limiting mesophyll conductance. PMID:28419340

  20. Growth Description for Vessel Wall Adaptation: A Thick-Walled Mixture Model of Abdominal Aortic Aneurysm Evolution.

    PubMed

    Grytsan, Andrii; Eriksson, Thomas S E; Watton, Paul N; Gasser, T Christian

    2017-08-25

    (1) Background: Vascular tissue seems to adapt towards stable homeostatic mechanical conditions, however, failure of reaching homeostasis may result in pathologies. Current vascular tissue adaptation models use many ad hoc assumptions, the implications of which are far from being fully understood; (2) Methods: The present study investigates the plausibility of different growth kinematics in modeling Abdominal Aortic Aneurysm (AAA) evolution in time. A structurally motivated constitutive description for the vessel wall is coupled to multi-constituent tissue growth descriptions; Constituent deposition preserved either the constituent's density or its volume, and Isotropic Volume Growth (IVG), in-Plane Volume Growth (PVG), in-Thickness Volume Growth (TVG) and No Volume Growth (NVG) describe the kinematics of the growing vessel wall. The sensitivity of key modeling parameters is explored, and predictions are assessed for their plausibility; (3) Results: AAA development based on TVG and NVG kinematics provided not only quantitatively, but also qualitatively different results compared to IVG and PVG kinematics. Specifically, for IVG and PVG kinematics, increasing collagen mass production accelerated AAA expansion which seems counterintuitive. In addition, TVG and NVG kinematics showed less sensitivity to the initial constituent volume fractions, than predictions based on IVG and PVG; (4) Conclusions: The choice of tissue growth kinematics is of crucial importance when modeling AAA growth. Much more interdisciplinary experimental work is required to develop and validate vascular tissue adaption models, before such models can be of any practical use.

  1. Intraluminal thrombus thickness is not related to lower concentrations of trace elements in the wall of infrarenal abdominal aortic aneurysms.

    PubMed

    Ziaja, Damian; Kita, Andrzej; Janowska, Joanna; Pawlicki, Krzysztof; Mikuła, Barbara; Sznapka, Mariola; Chudek, Jerzy; Ziaja, Krzysztof

    2014-01-01

    Intraluminal thrombus (ILT) formation plays a significant role in the progression of infrarenal abdominal aortic aneurysms (AAA). Potentially, as ILT thickness increases the availability of trace elements in the aneurysm wall could decrease thereby leading to oxidative stress and intensifying pro-inflammatory cytokine generation. To determine if thrombus thickness is related to the concentration of trace elements in the wall of infrarenal AAA. The concentrations of trace elements in the wall of the aneurysm sack and ILT obtained from 19 consecutive patients during surgery for infrarenal AAA were determined using emission spectrometry. The concentrations of magnesium, zinc, manganese, and lead in the wall of AAA were significantly greater than in the ILT. Only the concentration of copper was lower in the AAA wall compared with the thrombus. The concentration of calcium, phosphorus, zinc, lead, copper, and magnesium increased with ILT thickness. The concentrations of no other trace elements in the wall of AAA were found to be related to the ILT thickness. Intraluminal thrombus thickness is not associated with a lower concentration of trace elements in the wall of the infrarenal AAA. Thus, the intraluminal thrombus participates in the progression of AAA by mechanisms independent of trace element supply to the wall of the aneurysm sack. Copyright © 2013 Elsevier GmbH. All rights reserved.

  2. Designing living walls for greywater treatment.

    PubMed

    Fowdar, Harsha S; Hatt, Belinda E; Breen, Peter; Cook, Perran L M; Deletic, Ana

    2017-03-01

    Greywater is being increasingly used as an alternative water source to reduce potable water demand and to alleviate pressure on sewerage systems. This paper presents the development of a low energy and low maintenance greywater treatment technology: a living wall system, employing ornamental plants (including vines) grown in a sand filter on a side of a building to treat shower, bath, and washing basin wastewaters. The system can, at the same time, provide critical amenity and micro-climate benefits to our cities. A large scale column study was conducted in Melbourne, Australia, to investigate the following design and operational factors of the proposed system: plant species, saturated zone design, rest period, hydraulic loading rate and pollutant inflow concentration. The results indicate that the use of ornamental species (e.g. Canna lilies, Lonicera japonica, ornamental grape vine) can contribute to pollutant removal. Vegetation selection was found to be particularly important for nutrient removal. While a wider range of tested plant species was effective for nitrogen removal (>80%), phosphorus removal was more variable (-13% to 99%) over the study period, with only a few tested plants being effective - Carex appressa and Canna lilies were the best performers. It was also found that phosphorus removal can be compromised over the longer term as a result of leaching. Excellent suspended solids and organics removal efficiencies can be generally achieved in these systems (>80% for TSS and >90% for BOD) with plants having a relatively small impact. Columns had an acceptable infiltration capacity after one year of operation. When planted with effective species (e.g. Carex appressa and Canna lilies), it is expected that performance will not be significantly affected by longer rest periods and higher pollutant concentrations in the early years of system operation. The results of this study, thus, demonstrate that innovative and aesthetically pleasing living walls can be

  3. A hybrid method for airway segmentation and automated measurement of bronchial wall thickness on CT.

    PubMed

    Xu, Ziyue; Bagci, Ulas; Foster, Brent; Mansoor, Awais; Udupa, Jayaram K; Mollura, Daniel J

    2015-08-01

    Inflammatory and infectious lung diseases commonly involve bronchial airway structures and morphology, and these abnormalities are often analyzed non-invasively through high resolution computed tomography (CT) scans. Assessing airway wall surfaces and the lumen are of great importance for diagnosing pulmonary diseases. However, obtaining high accuracy from a complete 3-D airway tree structure can be quite challenging. The airway tree structure has spiculated shapes with multiple branches and bifurcation points as opposed to solid single organ or tumor segmentation tasks in other applications, hence, it is complex for manual segmentation as compared with other tasks. For computerized methods, a fundamental challenge in airway tree segmentation is the highly variable intensity levels in the lumen area, which often causes a segmentation method to leak into adjacent lung parenchyma through blurred airway walls or soft boundaries. Moreover, outer wall definition can be difficult due to similar intensities of the airway walls and nearby structures such as vessels. In this paper, we propose a computational framework to accurately quantify airways through (i) a novel hybrid approach for precise segmentation of the lumen, and (ii) two novel methods (a spatially constrained Markov random walk method (pseudo 3-D) and a relative fuzzy connectedness method (3-D)) to estimate the airway wall thickness. We evaluate the performance of our proposed methods in comparison with mostly used algorithms using human chest CT images. Our results demonstrate that, on publicly available data sets and using standard evaluation criteria, the proposed airway segmentation method is accurate and efficient as compared with the state-of-the-art methods, and the airway wall estimation algorithms identified the inner and outer airway surfaces more accurately than the most widely applied methods, namely full width at half maximum and phase congruency.

  4. Heterogeneous atrial wall thickness and stretch promote scroll waves anchoring during atrial fibrillation

    PubMed Central

    Yamazaki, Masatoshi; Mironov, Sergey; Taravant, Clément; Brec, Julien; Vaquero, Luis M.; Bandaru, Krishna; Avula, Uma Mahesh R; Honjo, Haruo; Kodama, Itsuo; Berenfeld, Omer; Kalifa, Jérôme

    2012-01-01

    Aims Atrial dilatation and myocardial stretch are strongly associated with atrial fibrillation (AF). However, the mechanisms by which the three-dimensional (3D) atrial architecture and heterogeneous stretch contribute to AF perpetuation are incompletely understood. We compared AF dynamics during stretch-related AF (pressure: 12cmH2O) in normal sheep hearts (n = 5) and in persistent AF (PtAF, n = 8)-remodelled hearts subjected to prolonged atrial tachypacing. We hypothesized that, in the presence of stretch, meandering 3D atrial scroll waves (ASWs) anchor in regions of large spatial gradients in wall thickness. Methods and results We implemented a high-resolution optical mapping set-up that enabled simultaneous epicardial- and endoscopy-guided endocardial recordings of the intact atria in Langendorff-perfused normal and PtAF (AF duration: 21.3 ± 11.9 days) hearts. The numbers and lifespan of long-lasting ASWs (>3 rotations) were greater in PtAF than normal (lifespan 0.9 ± 0.5 vs. 0.4 ± 0.2 s/(3 s of AF), P< 0.05). Than normal hearts, focal breakthroughs interacted with ASWs at the posterior left atrium and left atrial appendage to maintain AF. In PtAF hearts, ASW filaments seemed to span the atrial wall from endocardium to epicardium. Numerical simulations using 3D atrial geometries (Courtemanche-Ramirez-Nattel human atrial model) predicted that, similar to experiments, filaments of meandering ASWs stabilized at locations with large gradients in myocardial thickness. Moreover, simulations predicted that ionic remodelling and heterogeneous distribution of stretch-activated channel conductances contributed to filament stabilization. Conclusion The heterogeneous atrial wall thickness and atrial stretch, together with ionic and anatomic remodelling caused by AF, are the main factors allowing ASW and AF maintenance. PMID:22227155

  5. Structure and Properties of Thick-Walled Joints of Alloy 1570s Prepared by Friction Stir Welding

    NASA Astrophysics Data System (ADS)

    Velichko, O. V.; Ivanov, S. Yu.; Karkhin, V. A.; Lopota, V. A.; Makhin, I. D.

    2016-09-01

    The microstructure and mechanical properties of thick-walled joints of Al - Mg - Sc alloy 1570S, prepared by friction stir welding are studied. Joint microstructural and mechanical inhomogeneity are revealed.

  6. A joint thermal and electromagnetic diagnostics approach for the inspection of thick walls

    NASA Astrophysics Data System (ADS)

    Le Touz, Nicolas; Dumoulin, Jean; Gennarelli, Gianluca; Soldovieri, Francesco

    2017-02-01

    In this study, we present an inversion approach to detect and localize inclusions in thick walls under natural solicitations. The approach is based on a preliminary analysis of surface temperature field evolution with time (for instance acquired by infrared thermography); subsequently, this analysis is improved by taking advantage of a priori information provided by ground-penetrating radar reconstruction of the structure under investigation. In this way, it is possible to improve the accuracy of the images achievable with the stand-alone thermal reconstruction method in the case of quasi-periodic natural excitation.

  7. IFE thick liquid wall chamber dynamics: Governing mechanisms andmodeling and experimental capabilities

    SciTech Connect

    Raffray, A.R.; Meier, W.; Abdel-Khalik, S.; Bonazza, R.; Calderoni, P.; Debonnel, C.S.; Dragojlovic, Z.; El-Guebaly, L.; Haynes,D.; Latkowski, J.; Olson, C.; Peterson, P.F.; Reyes, S.; Sharpe, P.; Tillack, M.S.; Zaghloul, M.

    2005-01-24

    For thick liquid wall concepts, it is important to understand the different mechanisms affecting the chamber dynamics and the state of the chamber prior to each shot a compared with requirements from the driver and target. These include ablation mechanisms, vapor transport and control, possible aerosol formation, as well as protective jet behavior. This paper was motivated by a town meeting on this subject which helped identify the major issues, assess the latest results, review the capabilities of existing modeling and experimental facilities with respect to addressing remaining issues, and helping guide future analysis and R&D efforts; the paper covers these exact points.

  8. Design complexity and fracture control in the equine hoof wall.

    PubMed

    Kasapi, M A; Gosline, J M

    1997-06-01

    Morphological and mechanical studies were conducted on samples of equine hoof wall to help elucidate the relationship between form and function of this complex, hierarchically organized structure. Morphological findings indicated a dependence of tubule size, shape and helical alignment of intermediate filaments (IFs) within the lamellae on the position through the wall thickness. The plane of the intertubular IFs changed from perpendicular to the tubule axis in the inner wall to almost parallel to the tubule axis in the outer wall. Morphological data predicted the existence of three crack diversion mechanisms which might prevent cracks from reaching the sensitive, living tissues of the hoof: a mid-wall diversion mechanism of intertubular material to inhibit inward and upward crack propagation, and inner- and outer-wall diversion mechanisms that prevent inward crack propagation. Tensile and compact tension fracture tests were conducted on samples of fully hydrated equine hoof wall. Longitudinal stiffness decreased from 0.56 to 0.30 GPa proceeding inwardly, whereas ultimate (maximum) properties were constant. Fracture toughness parameters indicated that no compromise results from the declining stiffness, with J-integral values ranging from 5.5 to 7.8 kJ m-2 through the wall thickness; however, highest toughness was found in specimens with cracks initiated tangential to the wall surface (10.7 kJ m-2). Fracture paths agreed with morphological predictions and further suggested that the wall has evolved into a structure capable of both resisting and redirecting cracks initiated in numerous orientations.

  9. Effect of bladder wall thickness on miniature pneumatic artificial muscle performance.

    PubMed

    Pillsbury, Thomas E; Kothera, Curt S; Wereley, Norman M

    2015-09-28

    Pneumatic artificial muscles (PAMs) are actuators known for their high power to weight ratio, natural compliance and light weight. Due to these advantages, PAMs have been used for orthotic devices and robotic limbs. Small scale PAMs have the same advantages, as well as requiring greatly reduced volumes with potential application to prostheses and small scale robotics. The bladder of a PAM affects common actuator performance metrics, specifically: blocked force, free contraction, hysteresis, and dead-band pressure. This paper investigates the effect that bladder thickness has on static actuation performance of small scale PAMs. Miniature PAMs were fabricated with a range of bladder thicknesses to quantify the change in common actuator performance metrics specifically: blocked force, free contraction, and dead-band pressure. These PAMs were then experimentally characterized in quasi-static conditions, where results showed that increasing bladder wall thickness decreases blocked force and free contraction, while dead-band pressure increases. A nonlinear model was then applied to determine the structure of the stress-strain relationship that enables accurate modeling and the minimum number of terms. Two nonlinear models are compared and the identified parameters are analyzed to study the effect of the bladder thickness on the model.

  10. Fatigue life analysis and tests for thick-walled cylinders including effects of overstrain and axial grooves

    NASA Astrophysics Data System (ADS)

    Underwood, J. H.; Parker, A. P.

    1994-09-01

    A fracture mechanics-based fatigue life analysis was developed for pressurized thick-walled cylinders autofrettaged by overstrain and with one or several semi-elliptical-shaped axial grooves at the inner diameter. The fatigue life for a crack initiating at the root of the groove was calculated for various cylinder, groove, and crack configurations and for different material yielding condition. Comparisons were made with fatigue crack growth and laboratory life results from A723 thick-walled cylinders in which cannon firing tests were first performed to produce axial erosion grooves, followed by cyclic hydraulic pressurization to failure in the laboratory. The life analysis, with an initial crack size based on the expected preexisting defects, gave a good description of the crack growth and fatigue life of the tests for cylinders with and without grooves. General fatigue life calculations summarized important and configurational effects on the fatigue life design of overstrained cylinders, including effects of material yield strength, cylinder diameter ratio, stress concentration-factor, and initial crack size.

  11. Effect of subcooling and wall thickness on pool boiling from downward-facing curved surfaces in water

    SciTech Connect

    El-Genk, M.S.; Glebov, A.G.

    1995-09-01

    Quenching experiments were performed to investigate the effects of water subcooling and wall thickness on pool boiling from a downward-facing curved surface. Experiments used three copper sections of the same diameter (50.8 mm) and surface radius (148 mm), but different thickness (12.8, 20 and 30 mm). Local and average pool boiling curves were obtained at saturation and 5 K, 10 K, and 14 K subcooling. Water subcooling increased the maximum heat flux, but decreased the corresponding wall superheat. The minimum film boiling heat flux and the corresponding wall superheat, however, increased with increased subcooling. The maximum and minimum film boiling heat fluxes were independent of wall thickness above 20 mm and Biot Number > 0.8, indicating that boiling curves for the 20 and 30 thick sections were representative of quasi steady-state, but not those for the 12.8 mm thick section. When compared with that for a flat surface section of the same thickness, the data for the 12.8 mm thick section showed significant increases in both the maximum heat flux (from 0.21 to 0.41 MW/m{sup 2}) and the minimum film boiling heat flux (from 2 to 13 kW/m{sup 2}) and about 11.5 K and 60 K increase in the corresponding wall superheats, respectively.

  12. Consistent HYLIFE wall design that withstands transient loading conditions

    SciTech Connect

    Pitts, J.H.

    1980-10-01

    The design for a first structural wall (FSW) promises to satisfy the impact and thermal stress loads for the 30-year lifetime anticipated for the HYLIFE reaction chamber. The FSW is a 50-mm-thick cylindrical plate that is 10 m in diameter; it can withstand a rapidly varying liquid metal impact stress up to a peak of 60 MPa, combined with slowly varying thermal stresses up to 86 MPa. We selected 2 1/4 Cr-1 Mo ferritic steel as the structural material because it has adequate fatigue properties and yield strength at the peak operating temperature of 810/sup 0/K, is compatible with liquid lithium, and has good neutron activation characteristics.

  13. Influence of Wall Thickness on Microstructure of the Directionally Solidified Turbine Vane with High Withdrawal Rate

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Gong, Xiufang; Li, Bo; Song, Xiaolong; Yang, Gongxian; Tao, Fei

    In order to investigate the influence of the specimen thickness on the microstructure of directionally solidified (DS) hollow gas turbine vanes prepared with constant representative casting parameters, characteristic morphologies of dendrite and MC carbides in the transverse section were studied systematically. Optical microscope (OM) images show that the prime dendrite arm spacing falling within the range of 360-480 μm decreases with decreasing the wall thickness and secondary dendrite arms are abnormally prosperous in some regions, indicating that the morphology of dendrite and the prime dendrite arm spacing are correlated not only with thermal gradient and withdrawal rate but also with heat conduction condition. Scanning electron microscope (SEM) results exhibit that the morphology of MC carbides transforms gradually from blocky and rode-like appearance to script type and nodular morphology, finally to small blocks with distance away from the center of the vane wall; blocky carbides make up the greatest fraction of MC carbides present in this microstructure and are preferentially located in the interdendritic regions surround by a γ-γ' matrix and some of these carbides uniformly distribute parallel along one direction. It is interesting to note that some small Chinese-script type carbides occasionally locate within secondary dendrite trunks, which is different from current experimental and theoretical results. This may be related to large amounts of metallic element Ta in this material.

  14. Dissipative particle dynamics study of relationship between wall thickness and size in polymer vesicles

    NASA Astrophysics Data System (ADS)

    Xiao, Mengying; Wang, Rong; Xie, Daiqian

    2012-02-01

    Vesicles and membrane properties have long been thought to be essential for reproducing the natural environment of living cells. By using dissipative particle dynamics method, we have studied the relationship between wall thickness and size of vesicles obtained from A1BnA1 block copolymers, where block A is hydrophilic and block B is hydrophobic. Our findings suggest that, the wall thickness is sensitive to the size of vesicles at a low block length ratio of B/A, but insensitive to the size at a large ratio. It shows both weak and strong effects with a crossover point in between. These behaviors are consistent with the experimental results of Eisenberg and co-workers. Besides, an additional crossover point also has been observed. With the B/A ratio increases, the relationship goes from strong to weak behavior, and this transformation first appears to affect the outer area for large sized vesicles, and then to the inner area for small sized vesicles. These results may also be useful in delivery applications through controlling the hydrophobic membrane and the hydrophilic coronas.

  15. On what controls the spacing of spontaneous adiabatic shear bands in collapsing thick-walled cylinders

    NASA Astrophysics Data System (ADS)

    Lovinger, Zev; Rosenberg, Zvi; Rittel, Daniel

    2015-09-01

    Shear bands formation in collapsing thick walled cylinders occurs in a spontaneous manner. The advantage of examining spontaneous, as opposed to forced shear localization, is that it highlights the inherent susceptibility of the material to adiabatic shear banding without prescribed geometrical constraints. The Thick-Walled Cylinder technique (TWC) provides a controllable and repeatable technique to create and study multiple adiabatic shear bands. The technique, reported in the literature uses an explosive cylinder to create the driving force, collapsing the cylindrical sample. Recently, we developed an electro-magnetic set-up using a pulsed current generator to provide the collapsing force, replacing the use of explosives. Using this platform we examined the shear band evolution at different stages of formation in 7 metallic alloys, spanning a wide range of strength and failure properties. We examined the number of shear bands and spacing between them for the different materials to try and figure out what controls these parameters. The examination of the different materials enabled us to better comprehend the mechanisms which control the spatial distribution of multiple shear bands in this geometry. The results of these tests are discussed and compared to explosively driven collapsing TWC results in the literature and to existing analytical models for spontaneous adiabatic shear localization.

  16. Optimization of Cone Wall Thickness to Reduce High Energy Electron Generation for Fast-Ignition Scheme

    NASA Astrophysics Data System (ADS)

    Kojima, Sadaoki; Zhe, Zhang; Sawada, Hiroshi; Firex Team

    2015-11-01

    In Fast Ignition Inertial Confinement Fusion, optimization of relativistic electron beam (REB) accelerated by a high-intensity laser pulse is critical for the efficient core heating. The high-energy tail of the electron spectrum is generated by the laser interaction with a long-scale-length plasma and does not efficiently couple to a fuel core. In the cone-in-shell scheme, long-scale-length plasmas can be produced inside the cone by the pedestal of a high-intensity laser, radiation heating of the inner cone wall and shock wave from an implosion core. We have investigated a relation between the presence of pre-plasma inside the cone and the REB energy distribution using the Gekko XII and 2kJ-PW LFEX laser at the Institute of Laser Engineering. The condition of an inner cone wall was monitored using VISAR and SOP systems on a cone-in-shell implosion. The generation of the REB was measured with an electron energy analyzer and a hard x-ray spectrometer on a separate shot by injecting the LFEX laser in an imploded target. The result shows the strong correlation between the preheat and high-energy tail generation. Optimization of cone-wall thickness for the fast-ignition will be discussed. This work is supported by NIFS, MEXT/JSPS KAKENHI Grant and JSPS Fellows (Grant Number 14J06592).

  17. On the Opening of Thick Walled Elastic Tubes: A Fluid-Structure Model for Acid Reflux

    NASA Astrophysics Data System (ADS)

    Ghosh, Sudip; Kahrilas, Peter

    2005-11-01

    A coupled fluid-structure mathematical model was developed to quantify rapid opening of thick-walled elastic tubes, a phenomenon underlying biological flows such as gastroesophageal reflux disease (GERD). The wall was modeled using non-linear finite deformation theory to predict space-time radial distention of an axisymmetric tube with luminal fluid flow. Anisotropic azimuthal and longitudinal muscle-induced stresses were incorporated, and interstitial material properties were assumed isotropic and linearly elastic. Fluid flow was modeled using lubrication theory with inertial correction. Opening and flow were driven by a specified inflow pressure and zero pressure gradient was specified at outflow. No-slip and surface force balance were applied at the fluid-wall interface. Viscoelasticity was modeled with ad hoc damping and the evolution of the tube geometry was predicted at mid-layer. A potentially important discovery was made when applied to studies of initiation of opening with GERD: while material stiffness is of minor consequence, small changes in resting lumen distension (˜2 mm diameter) may be a sensitive distinguishing feature of the disease.

  18. Multiphysics design optimization model for structural walls incorporating phase-change materials

    NASA Astrophysics Data System (ADS)

    Stockwell, A.; Neithalath, N.; Rajan, S. D.

    2015-03-01

    The development of energy-efficient building envelopes has been an ongoing effort in many countries owing to the pressing need to achieve energy independence. In this study numerical optimization techniques and finite element analysis provide the means to find a compromise point between adding phase-change materials (PCMs) to a concrete wall, the energy savings and the wall's structural capacity. The primary objective is to minimize the overall lifetime cost of a wall by understanding the implications of PCM layer thickness, material properties and position in the wall on the overall energy consumption. While it is difficult to manually configure a typical wall for the lowest total cost, the developed computational framework provides an automated tool for searching for the best design. The results show that successful designs can be obtained where material and energy costs can be minimized through a judicious combination of existing building materials with thermal energy storage materials.

  19. Airway wall thickness is increased in COPD patients with bronchodilator responsiveness

    PubMed Central

    2014-01-01

    Rationale Bronchodilator responsiveness (BDR) is a common but variable phenomenon in COPD. The CT characteristics of airway dimensions that differentiate COPD subjects with BDR from those without BDR have not been well described. We aimed to assess airway dimensions in COPD subjects with and without BDR. Methods We analyzed subjects with GOLD 1–4 disease in the COPDGene® study who had CT airway analysis. We divided patients into two groups: BDR + (post bronchodilator ΔFEV1 ≥ 10%) and BDR-(post bronchodilator ΔFEV1 < 10%). The mean wall area percent (WA%) of six segmental bronchi in each subject was quantified using VIDA. Using 3D SLICER, airway wall thickness was also expressed as the square root wall area of an airway of 10 mm (Pi10) and 15 mm (Pi15) diameter. %Emphysema and %gas trapping were also calculated. Results 2355 subjects in the BDR-group and 1306 in the BDR + group formed our analysis. The BDR + group had a greater Pi10, Pi15, and mean segmental WA% compared to the BDR-group. In multivariate logistic regression using gender, race, current smoking, history of asthma, %emphysema, %gas trapping, %predicted FEV1, and %predicted FVC, airway wall measures remained independent predictors of BDR. Using a threshold change in FEV1 ≥ 15% and FEV1 ≥ 12% and 200 mL to divide patients into groups, the results were similar. Conclusion BDR in COPD is independently associated with CT evidence of airway pathology. This study provides us with greater evidence of changes in lung structure that correlate with physiologic manifestations of airflow obstruction in COPD. PMID:25248436

  20. Airway wall thickness is increased in COPD patients with bronchodilator responsiveness.

    PubMed

    Kim, Victor; Desai, Parag; Newell, John D; Make, Barry J; Washko, George R; Silverman, Edwin K; Crapo, James D; Bhatt, Surya P; Criner, Gerard J

    2014-08-08

    Bronchodilator responsiveness (BDR) is a common but variable phenomenon in COPD. The CT characteristics of airway dimensions that differentiate COPD subjects with BDR from those without BDR have not been well described. We aimed to assess airway dimensions in COPD subjects with and without BDR. We analyzed subjects with GOLD 1-4 disease in the COPDGene® study who had CT airway analysis. We divided patients into two groups: BDR + (post bronchodilator ΔFEV1 ≥ 10%) and BDR-(post bronchodilator ΔFEV1 < 10%). The mean wall area percent (WA%) of six segmental bronchi in each subject was quantified using VIDA. Using 3D SLICER, airway wall thickness was also expressed as the square root wall area of an airway of 10 mm (Pi10) and 15 mm (Pi15) diameter. %Emphysema and %gas trapping were also calculated. 2355 subjects in the BDR-group and 1306 in the BDR + group formed our analysis. The BDR + group had a greater Pi10, Pi15, and mean segmental WA% compared to the BDR-group. In multivariate logistic regression using gender, race, current smoking, history of asthma, %emphysema, %gas trapping, %predicted FEV1, and %predicted FVC, airway wall measures remained independent predictors of BDR. Using a threshold change in FEV1 ≥ 15% and FEV1 ≥ 12% and 200 mL to divide patients into groups, the results were similar. BDR in COPD is independently associated with CT evidence of airway pathology. This study provides us with greater evidence of changes in lung structure that correlate with physiologic manifestations of airflow obstruction in COPD.

  1. Design of optical notch filters using apodized thickness modulation.

    PubMed

    Lyngnes, Ove; Kraus, James

    2014-02-01

    An apodized thickness design method for discrete layer notch filters is presented. The method produces error tolerant designs with low ripple in the passband regions without any additional numerical optimization. Several apodization functions including Gaussian, cosine squared, as well as quintic are considered. Theoretical and experimental results from ion beam deposited sample designs for single-notch as well as multinotch filters are presented. Good agreement is observed between the theoretical design and the experimental measurement even when the deposition process is only controlled on time. This demonstrates the low layer error sensitivity of the apodized designs.

  2. A method of computing the transient temperature of thick walls from arbitrary variation of adiabatic-wall temperature and heat-transfer coefficient

    NASA Technical Reports Server (NTRS)

    Hill, P R

    1958-01-01

    A method of calculating the temperature of thick walls has been developed in which the time series and the response to a unit triangle variation of surface temperature concepts are used, together with essentially standard formulas for transient temperature and heat flow into thick walls. The method can be used without knowledge of the mathematical tools of its development. The method is particularly suitable for determining the wall temperature in one-dimensional thermal problems in aeronautics where there is a continuous variation of the heat-transfer coefficient and adiabatic-wall temperature. The method also offers a convenient means for solving the inverse problem of determining the heat-flow history when temperature history is known.

  3. Computed tomography scan measurement of abdominal wall thickness for application of near-infrared spectroscopy probes to monitor regional oxygen saturation index of gastrointestinal and renal circulations in children.

    PubMed

    Balaguru, Duraisamy; Bhalala, Utpal; Haghighi, Mohammad; Norton, Karen

    2011-05-01

    To measure abdominal wall thickness to determine the depth at which the renal vascular bed and mesenteric vascular bed are located, and to determine the appropriate site for placement of near-infrared spectroscopy probes for accurate monitoring regional oxygen saturation index in children. Abdominal computerized tomography scans in children were used to measure the abdominal wall thickness and to ascertain the location of kidneys. Tertiary care children's hospital. Children 0-18 yrs of age; n = 38. None. The main mass of the kidneys is located between vertebral levels T12 and L2 on both sides. The left kidney is located about a half-vertebral length higher than the right kidney. Posterior abdominal wall thickness ranged from 6.6 to 115.8 mm (median, 22.1 mm). Posterolateral abdominal wall thickness ranged from 6.7 to 114.5 mm (median, 19.6 mm). Anterior abdominal wall thickness in the supraumbilical level ranged from 3.5 to 62.9 mm (median, 16.0 mm). All abdominal wall thicknesses correlated better with weight of the subjects than their age. Abdominal wall thickness potentially exceeds the sampling depth of currently used near-infrared spectroscopy probes above a certain body size. Application of current near-infrared spectroscopy probes and design of future probes should consider patient size variations in the pediatric population.

  4. Design of a Variable Thickness Plate to Focus Bending Waves

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Lin, Sz-Chin Steven; Cabell, Randolph H.; Huang, Tony Jun

    2012-01-01

    This paper describes the design of a thin plate whose thickness is tailored in order to focus bending waves to a desired location on the plate. Focusing is achieved by smoothly varying the thickness of the plate to create a type of lens, which focuses structural-borne energy. Damping treatment can then be positioned at the focal point to efficiently dissipate energy with a minimum amount of treatment. Numerical simulations of both bounded and unbounded plates show that the design is effective over a broad frequency range, focusing traveling waves to the same region of the plate regardless of frequency. This paper also quantifies the additional energy dissipated by local damping treatment installed on a variable thickness plate relative to a uniform plate.

  5. Residual stress analysis in forming process of filament wound thick-walled CFRP pipes

    SciTech Connect

    Kondo, Toshimi; Sekine, Hideki; Nakano, Kunio

    1995-11-01

    Residual stress analysis for the cracking phenomenon of filament would thick-walled CFRP pipes, which frequently occurs in the forming process of curing and thermal cycling through the course of the wet filament winding, was made from both the experimental and theoretical points of view. A simple analytical model to study the cracking in the CFRP pipes was proposed. The pipes are multilayered and reinforced in the axial and circumferential directions alternatively by carbon fibers. Taking account of the anisotropy of mechanical and thermal properties including the shrinkage strain, which depend considerably on the temperature, the residual stresses in the CFRP pipes were elucidated in the forming process, particularly, in cooling of the cure process.

  6. Helium ion microscopy based wall thickness and surface roughness analysis of polymer foams obtained from high internal phase emulsion.

    PubMed

    Rodenburg, C; Viswanathan, P; Jepson, M A E; Liu, X; Battaglia, G

    2014-04-01

    Due to their wide range of applications, porous polymers obtained from high internal phase emulsions have been widely studied using scanning electron microscopy. However, due to their lack of electrical conductivity, quantitative information of wall thicknesses and surface roughness, which are of particular interest to tissue engineering, has not been obtained. Here, Helium Ion Microscopy is used to examine uncoated polymer foams and some very strong but unexpected contrast is observed, the origin of which is established here. Based on this analysis, a method for the measurement of wall thickness variations and wall roughness measurements has been developed, based on the modeling of Helium ion transmission. The results presented here indicate that within the walls of the void structure there exist small features with height variations of ~30 nm and wall thickness variations from ~100 nm to larger 340 nm in regions surrounding interconnecting windows within the structure. The suggested imaging method is applicable to other porous carbon based structures with wall thicknesses in the range of 40-340 nm.

  7. Observation of cerebral aneurysm wall thickness using intraoperative microscopy: clinical and morphological analysis of translucent aneurysm.

    PubMed

    Song, Jihye; Park, Jung Eon; Kim, Hyoung Ryoul; Shin, Yong Sam

    2015-06-01

    Intracranial aneurysms suffer various interactions between hemodynamics and pathobiology, and rupture when this balance disrupted. Aneurysm wall morphology is a result of these interactions and reflects the quality of the maturation. However, it is a poorly documented in previous studies. The purpose of this study is to observe aneurysm wall thickness and describe the characteristics of translucent aneurysm by analyzing clinical and morphological parameters. 253 consecutive patients who underwent clipping surgery in a single institute were retrospectively analyzed. Only middle cerebral artery aneurysms (MCA) which exposed most part of the dome during surgery were included. Aneurysms were categorized based on intraoperative video findings. Aneurysms more than 90 % of super-thin dome and any aneurysms with entirely super-thin-walled daughter sac were defined as translucent aneurysm. A total of 110 consecutive patients with 116 unruptured MCA aneurysms were included. Ninety-two aneurysms (79.3 %) were assigned to the not-translucent group and 24 (20.7 %) to the translucent group. The relative proportion of translucent aneurysm in each age group was highest at ages 50-59 years and absent at ages 30-39 and 70-79 years. There was a trend that translucent aneurysms were smaller in size (p = 0.019). Multivariate logistic analysis showed that translucent aneurysm was strongly correlated with height <3 mm (p = 0.003). We demonstrated that the translucent aneurysms were smaller in size and the aneurysm height <3 mm was related. These results may provide information in determining treatment strategies in patients with small size aneurysm.

  8. Development of Thick B4C Coatings for the First Wall of W7-X

    NASA Astrophysics Data System (ADS)

    Kötterl, S.; Bolt, H.; Greuner, H.; Huber, A.; Linke, J.; Mayer, M.; Pospieszczyk, A.; Renner, H.; Roth, J.; Schweer, B.; Sergienko, G.; Valenza, D.

    For the actively cooled first wall panels of the W7-X stellarator under construction at Greifswald, Germany, boron carbide (B4C) coatings with a thickness up to 500 μm are being developed as plasma facing surface on the stainless steel component. Different coating technologies (vacuum plasma spray (VPS), atmospherical plasma spray (APS)) are investigated. Characterisation of the coatings comprises metallo"graphic and SEM investigations, impurity determination and measurement of the thermal conductivity, characterisation of the sputtering behaviour and the behaviour under plasma exposure. First in-pile-tests in the tokamak TEXTOR-94 at the Research Centre Juelich have been performed. 10 poloidal limiter elements and 5 test limiters made of copper with a 170 μm thick B4C VPS coating were exposed to plasma discharges with ohmic and additional heating. By varying the limiter positions and plasma density, different loading conditions were imposed. After exposure, the test limiters were removed for further analyses. First results showed the formation of small craters in the coating, probably due to arcing. Although melting occurred within a limited zone around the craters, the coatings did not detach from the substrate or show severe cracking outside the molten area.

  9. Chronic obstructive pulmonary disease: thin-section CT measurement of airway wall thickness and lung attenuation.

    PubMed

    Orlandi, Ilaria; Moroni, Chiara; Camiciottoli, Gianna; Bartolucci, Maurizio; Pistolesi, Massimo; Villari, Natale; Mascalchi, Mario

    2005-02-01

    To prospectively evaluate airway wall thickness and lung attenuation at spirometrically gated thin-section computed tomography (CT) in patients with chronic obstructive pulmonary disease (COPD) and to correlate gated CT findings with pulmonary function test (PFT) results. The ethical committee approved the study, and all patients gave informed consent. Forty-two consecutive patients with COPD (20 with and 22 without chronic bronchitis [CB]) underwent gated thin-section CT and PFTs on the same day. The percentage wall area (PWA) and the thickness-to-diameter ratio (TDR) for all depicted bronchi that were round and larger than 2 mm in diameter, the mean lung attenuation (MLA), and the pixel index (PI) at -950 HU were determined. The reproducibility of the airway measurements was preliminarily tested by performing a five-trial examination in a patient with COPD and in a control patient. Differences in airway and lung attenuation measurements between the patients with and those without CB were evaluated at Mann-Whitney U testing. Simple and multiple regression analyses were used to assess the correlation between thin-section CT and PFT measurements. The mean intraoperator coefficient of variation for airway measurements was 7.8% (range, 3.8%-13.4%). An average of nine bronchi per patient were assessed. Patients with CB had significantly higher PWAs, TDRs, and MLAs and significantly lower PIs than patients without CB (P < .05 for all values). The combination of PWA, TDR, and PWA normalized to body weight correlated significantly (P < .05) with the forced expiratory volume in 1 second-to-slow vital capacity ratio and the diffusing capacity of the lung for carbon monoxide in patients with but not in patients without CB. PFT results correlated better with MLA and PI in patients without CB. Bronchial wall measurements differ between patients who have COPD with CB and those who have COPD without CB. The correlation between airway dimensions and indexes of airway obstruction

  10. Conceptual design of the INTOR first-wall system

    SciTech Connect

    Smith, D.L.; Majumdar, S.; Mattas, R.F.; Turner, L.; Jung, J.; Abdou, M.A.; Bowers, D.; Trachsel, C.; Merrill, B.

    1981-10-01

    The design concept and performance characteristics of the first-wall design for the phase-1 INTOR (International Tokamak Reactor) study is described. The reference design consists of a water-cooled stainless steel panel. The major uncertainty regarding the performance of the bare stainless steel wall relates to the response of a thin-melt layer predicted to form on limited regions during a plasma disruption. A more-complex backup design, which incorporates radiatively cooled graphite tiles on the inboard wall, is briefly described.

  11. Axisymmetric Tandem Mirror Magnetic Fusion Energy Power Plant with Thick Liquid-Walls

    SciTech Connect

    Moir, R W; Rognlien, T D

    2006-04-26

    A fusion power plant is described that utilizes a new version of the tandem mirror device including spinning liquid walls. The magnetic configuration is evaluated with an axisymmetric equilibrium code predicting an average beta of 60%. The geometry allows a flowing molten salt, (flibe-Li{sub 2}BeF{sub 4}), which protects the walls and structures from damage arising from neutrons and plasma particles. The free surface between the liquid and the burning plasma is heated by bremsstrahlung radiation, line radiation, and by neutrons. The temperature of the free surface of the liquid is calculated, and then the evaporation rate is estimated from vapor-pressure data. The allowed impurity concentration in the burning plasma is taken as 1% fluorine, which gives a 17% reduction in the fusion power owing to D/T fuel dilution, with F line-radiation causing minor power degradation. The end leakage power density of 0.6 MW/m{sup 2} is readily handled by liquid jets. The tritium breeding is adequate with natural lithium. A number of problem areas are identified that need further study to make the design more self-consistent and workable; however, the simple geometry and the use of liquid walls promise the cost of power competitive with that from fission and coal.

  12. Design studies of an aluminum first wall for INTOR

    SciTech Connect

    Powell, J.R.; Fillo, J.A.; Yu, W.S.; Hsieh, S.Y.; Pearlman, H.; Kramer, R.; Franz, E.; Craig, A.; Farrell, K.

    1980-01-01

    Besides the high erosion rates (including evaporation) expected for INTOR, there may also be high heat fluxes to the first wall, e.g., approx. 9 (Case I) to 24 (Case II) W/cm/sup 2/, from two sources - radiation and charge exchange neutrals. There will also be internal heat generation by neutron and gamma deposition. An aluminum first wall design is analyzed, which substantially reduces concerns about survivability of the first wall during INTOR's operating life.

  13. Qualitative Reliability Issues for Solid and Liquid Wall Fusion Design

    SciTech Connect

    Cadwallader, Lee Charles

    2001-01-01

    This report is an initial effort to identify issues affecting reliability and availability of solid and liquid wall designs for magnetic fusion power plant designs. A qualitative approach has been used to identify the possible failure modes of major system components and their effects on the systems. A general set of design attributes known to affect the service reliability has been examined for the overview solid and liquid wall designs, and some specific features of good first wall design have been discussed and applied to these designs as well. The two generalized designs compare well in regard to these design attributes. The strengths and weaknesses of each design approach are seen in the comparison of specific features.

  14. Qualitative Reliability Issues for Solid and Liquid Wall Fusion Designs

    SciTech Connect

    Cadwallader, L.C.

    2001-01-31

    This report is an initial effort to identify issues affecting reliability and availability of solid and liquid wall designs for magnetic fusion power plant designs. A qualitative approach has been used to identify the possible failure modes of major system components and their effects on the systems. A general set of design attributes known to affect the service reliability has been examined for the overview solid and liquid wall designs, and some specific features of good first wall design have been discussed and applied to these designs as well. The two generalized designs compare well in regard to these design attributes. The strengths and weaknesses of each design approach are seen in the comparison of specific features.

  15. Reconstruction of full-thickness chest wall defects using rectus abdominis musculocutaneous flap: A report of fifteen cases

    SciTech Connect

    Miyamoto, Y.; Hattori, T.; Niimoto, M.; Toge, T. )

    1986-02-01

    In 15 patients chest walls were excised because of recurrent breast cancer, radiation ulcer, or rib tumor. In most cases the full-thickness defect of the chest wall was about 10 x 10 cm. Reconstruction was performed using only a rectus abdominis musculocutaneous flap. No patient developed circulation problems in the flap or severe flail chest, and we had successful results in all our cases. These results show that the rectus abdominis musculocutaneous flap is quite effective and safe to use in the reconstruction of chest wall defects.

  16. Correlation of bladder wall thickness and treatment success in types of urinary incontinence.

    PubMed

    Akselim, Burak; Doğanay, Melike; Özcan, Nilay; Akselim, Sinem; Cavkaytar, Sabri

    2017-03-01

    The aim of the study was to investigate the correlation between mean bladder wall thickness (BWT) and treatment success in patients diagnosed with urinary incontinence, based on urodynamic test results. In this prospective study, patient urinary incontinence type was identified using urodynamic tests. Patients (N = 125) were categorized into three groups: urodynamic stress incontinence (SUI), detrusor over-activity (DO) and mixed urinary incontinence. Measurements from the bladder dome, anterior wall and trigone were averaged to calculate BWT. Student's t test and Mann-Whitney U test were used to compare pre-treatment BWT. Receiver operating characteristic (ROC) curve analysis was used to determine optimal cut-off values for BWT to predict treatment success. Mean pre-treatment BWT significantly differed between success and non-success groups for each urinary incontinence type (p value for the SUI, DO and MUI groups was 0.043, 0.001 and 0.002 respectively). Using ROC curves to anticipate the treatment success, a threshold was calculated for mean pre-treatment BWT; 5.05 mm for SUI (sensitivity 74 %, specificity 66 %, positive predictive value [PPV] 85 %, negative predictive value [NPV] 50 %), 4.98 mm for DO (sensitivity 73 %, specificity 92 %, PPV 95 %, NPV 63 %) and 5.31 mm for mixed type (sensitivity 88 %, specificity 73 %, PPV 79 %, NPV 85 %). The study results suggest a significant relationship between the pre-treatment BWT and the success of urinary incontinence treatment. The mean BWT may be used as a benchmark in assessing the responsiveness to treatment of urinary incontinence types.

  17. Electromagnetic approaches to wall characterization, wall mitigation, and antenna design for through-the-wall radar systems

    NASA Astrophysics Data System (ADS)

    Thajudeen, Christopher

    of ground reflections, and situations where they may be applied to the estimation of the parameters associated with an interior wall. It is demonstrated through extensive computer simulations and laboratory experiments that, by proper exploitation of the electromagnetic characteristics of walls, one can efficiently extract the constitutive parameters associated with unknown wall(s) as well as to characterize and image the intra-wall region. Additionally, it is possible, to a large extent, to remove the negative wall effects, such as shadowing and incorrect target localization, as well as to enhance the imaging and classification of targets behind walls. In addition to the discussion of post processing the radar data to account for wall effects, the design of antenna elements used for transmit (Tx) and receive (Rx) operations in TWR radars is also discussed but limited to antennas for mobile, handheld, or UAV TWR systems which impose design requirements such as low profiles, wide operational bands, and in most cases lend themselves to fabrication using surface printing techniques. A new class of wideband antennas, formed though the use of printed metallic paths in the form of Peano and Hilbert space-filling curves (SFC) to provide top-loading properties that miniaturize monopole antenna elements, has been developed for applications in conformal and/or low profile antennas systems, such as mobile platforms for TWRI and communication systems. Additionally, boresight gain enhancements of a stair-like antenna geometry, through the addition of parasitic self-similar patches and gate like ground plane structures, are presented.

  18. A new possibility of melt cooling in extrusion dies to prevent sagging-effects in thick-walled pipes

    NASA Astrophysics Data System (ADS)

    te Heesen, O.; Wortberg, J.

    2014-05-01

    One challenge in the extrusion process of thick-walled pipes is the cooling of the product. Besides the output of the extruder, the line speed is also limited by the efficiency of the cooling line. The cooling time increases according to the wall thickness of the pipe under otherwise equal process conditions. State of the art is the cooling of the outer surface in water tanks or spray-cool-tanks. In addition to that, it is possible to cool the inner surface by air that is sucked through the pipe. Despite these technologies it is problematic to cool down thick walled-products with the right speed. Especially thick-walled pipes show problems by cooling the layers in the middle of the wall. On the one hand an intensive cooling of the outer and inner surface of the pipe entail the formation of shrink holes in the middle of the pipe wall. On the other hand without a quick cooling the melt flow in circumferential direction because of the gravity takes place (sagging-effect). Because of this reason in the presented paper new possibilities of melt cooling in extrusion dies to prevent sagging-effects are given. An aimed cooling of the inbound melt layers inside the extrusion die could prevent the effect of melt flow in circumferential direction after the extrusion die, allows the specification of a specific temperature profile over the radius of the pipe wall and helps to reduce the melt temperature for rising mass throughputs and screw driving speeds of the extruder. It is also thinkable to influence the crystallization process and thereby the mechanical properties of the end-product by an aimed cooling of the inner pipe layers.

  19. Design of a three-component wall-mounted balance

    NASA Technical Reports Server (NTRS)

    Winkelmann, Allen E.; Gonzalez, Hugo A.

    1990-01-01

    The design and evaluation of a three-component, wall-mounted pyramidal balance for a small wind tunnel is discussed. The balance was designed to measure lift, drag, pitching moment, and angle of attack. The specific design of each component and mathematical models used to design the balance are covered. Balance evaluation consisted of calibration, tare, and interaction analysis.

  20. Utilization of a global data grid repository in CAD assessment of carotid wall thickness

    NASA Astrophysics Data System (ADS)

    Gutierrez, Marco A.; Lee, Jasper; Zhou, Zheng; Pilon, Paulo E.; Lage, Silvia G.

    2007-03-01

    A CAD method of calculating wall thickness of carotid vessels addresses the time-consuming issue of using B-mode ultrasound as well as inter- and intra-observer variability in results. Upon selection of a region-of-interest and filtering of a series of ultrasound carotid images, the CAD is able to measure the geometry of the lumen and plaque surfaces using a least-square fitting of the active contours during systole and diastole. To evaluate the approach, ultrasound image sequences from 30 patients were submitted to the procedure. The images were stored on an international data grid repository that consists of three international sites: Image Processing and Informatics (IPI) Laboratory at University of Southern California, USA; InCor (Heart Institute) at Sao Paulo, Brazil, and Hong Kong Polytechnic University, Hong Kong. The three chosen sites are connected with high speed international networks including the Internet2, and the Brazilian National Research and Education Network (RNP2). The Data Grid was used to store, backup, and share the ultrasound images and analysis results, which provided a large-scale and a virtual data system. In order to study the variability between the automatic and manual definition of artery boundaries, the pooled mean and the standard deviation for the difference between measurements of lumen diameter were computed. The coefficient of variation and correlation were also calculated. For the studied population the difference between manual and automatic measurement of the lumen diameter (LD) and intima-media-thickness (IMT) were 0.12 +/-0.10 and 0.09+/- 0.06, respectively.

  1. Bobbin-Tool Friction-Stir Welding of Thick-Walled Aluminum Alloy Pressure Vessels

    SciTech Connect

    Dalder, E C; Pastrnak, J W; Engel, J; Forrest, R S; Kokko, E; Ternan, K M; Waldron, D

    2007-06-06

    It was desired to assemble thick-walled Al alloy 2219 pressure vessels by bobbin-tool friction-stir welding. To develop the welding-process, mechanical-property, and fitness-for-service information to support this effort, extensive friction-stir welding-parameter studies were conducted on 2.5 cm. and 3.8 cm. thick 2219 Al alloy plate. Starting conditions of the plate were the fully-heat-treated (-T62) and in the annealed (-O) conditions. The former condition was chosen with the intent of using the welds in either the 'as welded' condition or after a simple low-temperature aging treatment. Since preliminary stress-analyses showed that stresses in and near the welds would probably exceed the yield-strength of both 'as welded' and welded and aged weld-joints, a post-weld solution-treatment, quenching, and aging treatment was also examined. Once a suitable set of welding and post-weld heat-treatment parameters was established, the project divided into two parts. The first part concentrated on developing the necessary process information to be able to make defect-free friction-stir welds in 3.8 cm. thick Al alloy 2219 in the form of circumferential welds that would join two hemispherical forgings with a 102 cm. inside diameter. This necessitated going to a bobbin-tool welding-technique to simplify the tooling needed to react the large forces generated in friction-stir welding. The bobbin-tool technique was demonstrated on both flat-plates and plates that were bent to the curvature of the actual vessel. An additional issue was termination of the weld, i.e. closing out the hole left at the end of the weld by withdrawal of the friction-stir welding tool. This was accomplished by friction-plug welding a slightly-oversized Al alloy 2219 plug into the termination-hole, followed by machining the plug flush with both the inside and outside surfaces of the vessel. The second part of the project involved demonstrating that the welds were fit for the intended service. This

  2. The effects of modified wall squat exercises on average adults' deep abdominal muscle thickness and lumbar stability.

    PubMed

    Cho, Misuk

    2013-06-01

    [Purpose] The purpose of this study was to compare the effects of bridge exercises applying the abdominal drawing-in method and modified wall squat exercises on deep abdominal muscle thickness and lumbar stability. [Subjects] A total of 30 subjects were equally divided into an experimental group and a control group. [Methods] The experimental group completed modified wall squat exercises, and the control group performed bridge exercises. Both did so for 30 minutes three times per week over a six-week period. Both groups' transversus abdominis (Tra), internal oblique (IO), and multifidus muscle thickness were measured using ultrasonography, while their static lumbar stability and dynamic lumbar stability were measured using a pressure biofeedback unit. [Results] A comparison of the pre-intervention and post-intervention measures of the experimental group and the control group was made; the Tra and IO thicknesses were significantly different in both groups. [Conclusion] The modified wall squat exercise and bridge exercise affected the thicknesses of the Tra and the IO muscles. While the bridge exercise requirs space and a mattress to lie on, the modified wall squat exercise can be conveniently performed anytime.

  3. Wall thickness measurement using resonant phenomena of circumferential Lamb waves generated by plural transducer elements located evenly on girth

    NASA Astrophysics Data System (ADS)

    Nishino, Hideo; Iwata, Kodai; Ishikawa, Masashi

    2016-07-01

    We present a novel method of measuring the pipe wall thickness using the resonance of the circumferential (C-) Lamb wave generated by a piezoelectric ring-shaped sensor (PS). The PS is a special device for an axially propagating torsional wave; however, the C-Lamb waves are generated simultaneously as spurious signals owing to the structure of the PS. Particularly under resonant conditions, the C-Lamb waves are dominantly generated, distorting the axially propagating wave. In this method, these troublesome spurious signals are used effectively for the measurement of the wall thickness under the PS location that is a dead zone of the PS itself. The method can compensate for its drawback, namely, the dead zone problem, without using additional instruments. In this study, the mechanisms of the generation and resonance of the C-Lamb waves were first explained. Secondly, the principle of the wall thickness estimation utilizing the resonance of the C-Lamb waves was proposed. Finally, experimental verifications were carried out. The estimated wall thicknesses agreed very well (maximum 1.5% error) with those measured by a micrometer caliper under suitable resonant conditions.

  4. Male gender and sonographic gall bladder wall thickness: important predictable factors for empyema and gangrene in acute cholecystitis.

    PubMed

    Khan, Muhammad Laiq-uz-Zaman; Abbassi, Mujeeb Rehman; Jawed, Muhammad; Shaikh, Ubedullah

    2014-02-01

    To underline the status of male gender and gall bladder wall thickness as significant risk factors for acute cholecystitis complications. The retrospective study, with purposive sampling of the patients of acute cholecystits in age above 18 years, who were operated within 10 days of onset of symptoms, was conducted at the Department of Surgery, Dow University Hospital, Karachi, by reviewing the patients' medical record from March 2010 to August 2012. Correlation of incidence of acute cholecystitis complications (empyema and gangrene) to male gender and to the sonographic gall bladder wall thickness more than 4.5 mm was analysed using SPSS 16. Out of 62 patients, 8 (13%) patients had gangrene while 10 (16.12%) had empyema. Overall, there were 21 (33.87%) males in the study. Ten (47.6%) of the male patients developed empyema or gangrene of the gall bladder as a complication of acute cholecystitis. Of the 41 (66.12%) female patients, only 8 (19.5%) developed these complications. There were 22 (35.48%) cases of gall bladders with sonographic wall thickness more than 4.5 mm who were operated for acute cholecystitis. Of them, 16 (72.7%) had empyema or gangrene. Male gender and sonographic gall bladder wall thickness more than 4.5 mm were statistically significant risk factors for suspicion of complicated acute cholecystitis (empyema/gangrene) and by using these risk factors, we can prioritise patients for surgery in the emergency room.

  5. Dynamic Response of a Pulse-Heated, Thick-Walled, Hollow Sphere: Validation of Code Numerics

    SciTech Connect

    Canaan, R.E.

    2000-01-19

    Volumetric pulse heating of a thick-walled hollow sphere is numerically investigated. The primary objective is to validate a variety of LLNL 30 hydrocodes for modeling the dynamic behavior of fissile/fissionable metals subject to rapid ''fission-heating'' transients. The 30 codes tested include both DYNA3D and NIKE3D, as well as the ''ASCI'' code, ALE3D. The codes are compared ''head-to-head'' and are benchmarked against a 1D finite difference solution to the problem that is derived from basic principles. Three pulse-heating transients are examined with full-width-half-maximum pulse durations of 41{micro}s, 85{micro}s, and 140{micro}s, respectively. These three transients produce a significant range of dynamic responses in the thermo-elastic regime. We present results for dynamic radial displacements and stresses for each pulse, and also discuss which code features/options worked best for these types of calculations. In general, the code results are in excellent agreement for the simple system considered. Validation of code numerics in simple systems is a key first step toward future application of the codes in more complicated geometries (U).

  6. Association of estrogen receptor beta gene polymorphisms with left ventricular mass and wall thickness in women.

    PubMed

    Peter, Inga; Shearman, Amanda M; Vasan, Ramachandran S; Zucker, Deborah R; Schmid, Christopher H; Demissie, Serkalem; Cupples, L Adrienne; Kuvin, Jeffrey T; Karas, Richard H; Mendelsohn, Michael E; Housman, David E; Benjamin, Emelia J

    2005-11-01

    Left ventricular (LV) hypertrophy is a significant risk factor for cardiovascular disease. Given sex-based differences in cardiac structure and remodeling, we hypothesized that variation in estrogen pathway genes might be associated with alteration of LV structure. We studied 1249 unrelated individuals, 547 men and 702 women (mean age 59 years) from the Framingham Heart Study. Eight single nucleotide polymorphisms in the genes for estrogen receptor alpha and estrogen receptor beta (ESR2) were tested for association with 5 LV measures: LV mass (LVM), LV wall thickness (LVWT), LV internal diameter at end-diastole and end-systole, and fractional shortening. Sex-specific multiple regression analyses were performed adjusting for age, weight, height, systolic and diastolic blood pressure, hypertension treatment, diabetes, and in women, menopausal status. In men, there was no evidence of association between the estrogen pathway polymorphisms tested and LV structure or function. In women, however, two polymorphisms, ESR2 rs1256031 and ESR2 rs1256059, in linkage disequilibrium with one another, were associated with LVM and LVWT (P = .0007 to .03); the association was most pronounced in those women with hypertension (P = .0006 to .01). The association did not appear to be explained by variation in blood pressure, plasma lipoprotein levels, or hyperglycemia. The ESR2 polymorphisms are associated with LV structural differences in women with hypertension in a community-based population. These data are consistent with the hypothesis that genetic factors may mediate part of the observed sex-based differences in LV structure and remodeling.

  7. The interaction of moderately strong shock waves with thick perforated walls of low porosity

    NASA Technical Reports Server (NTRS)

    Grant, D. J.

    1972-01-01

    A theoretical prediction is given of the flow through thick perforated walls of low porosity resulting from the impingement of a moderately strong traveling shock wave. The model was a flat plate positioned normal to the direction of the flow. Holes bored in the plate parallel to the direction of the flow provided nominal hole length-to-diameter ratios of 10:1 and an axial porosity of 25 percent of the flow channel cross section. The flow field behind the reflected shock wave was assumed to behave as a reservoir producing a quasi-steady duct flow through the model. Rayleigh and Fanno duct flow theoretical computations for each of three possible auxiliary wave patterns that can be associated with the transmitted shock (to satisfy contact surface compatibility) were used to provide bounding solutions as an alternative to the more complex influence coefficients method. Qualitative and quantitative behavior was verified in a 1.5- by 2.0-in. helium shock tube. High speed Schlieren photography, piezoelectric pressure-time histories, and electronic-counter wave speed measurements were used to assess the extent of correlation with the theoretical flow models. Reduced data indicated the adequacy of the bounding theory approach to predict wave phenomena and quantitative response.

  8. Stress-Strain State of Thick-Walled Filament-Wound Cylinders at the Macro-, Meso-, and Microscales During Cooling

    NASA Astrophysics Data System (ADS)

    Turusov, R. A.; Memarianfard, H.

    2016-07-01

    A comparative investigation of preconditions for cracking in thick-walled anisotropic unidirectionally and cross-ply filament-wound cylinders was performed. Experiments showed that it was much more difficult to obtain monolithic (without hoop cracks) thick cross-ply filament-wound cylinders than thick unidirectionally filament-wound cylinders. During cooling, cracks in cross-ply cylinders with a smaller ratio of thickness to the inner radius (at/of about 10% compared with 60% for unidirectionally filament-wound ones) are generally formed. However, the calculations of thermal stresses, by two different models, in a continuous anisotropic medium and in rings consisting of n alternating glass and resin layers showed that the radial tensile stresses in thick cross-ply filament-wound cylinders were lower than in a unidirectional structure. Only calculations by the FEM demonstrated higher radial tensile stresses in the cross-ply structure.

  9. New methodology for the walls design in buildings by numerical simulation of the thermal convection

    NASA Astrophysics Data System (ADS)

    Benachour, Elhadj; Draoui, Belkacem; Imine, Bachir; Asnoune, Khadidja; Mohamed, Elmir

    Buildings are complex systems composed of several elements, which are assembled to respond to a number of needs functional and symbolic according to set of legal and environmental requirements and potentially accommodate users with different levels of demand. Predicting the conception of the external wall is beneficial in the design of house and building structures.in this study, an analogy was used for the functions which are discretized by the finite difference method and integrated in the CFD code which is based on the finite volume method. The CFD software is used as a technique to modelling the behaviour of fluid and the thermal convection in the external wall of the house with different Rayleigh numbers [103≤ Ra ≤105]. In the second phase, we change the thickness of the wall several times and calculate the Nusselt number and exchange coefficient of heat transfer aims to find a cloud point respectively for the thicknesses e = 0, L /40, L /20 and L /10. After, we developed a relationship that helps us to know the exchange ratio for each thickness ( e ) belongs to the interval [0, L /10] by the Lagrange polynomial interpolation method for Rayleigh number equal 104 , and then we developed a FORTRAN program to control the nonlinear equation of order three. This method for predicting exchange coefficient of convection for to optimize the design of walls in buildings.

  10. Optimum heating of thick-walled pressure components assuming a quasi-steady state of temperature distribution

    NASA Astrophysics Data System (ADS)

    Dzierwa, Piotr; Trojan, Marcin; Taler, Dawid; Kamińska, Katarzyna; Taler, Jan

    2016-08-01

    As a result of the development of wind farms, the gas — steam blocks, which shall quickly ensure energy supply in case the wind velocity is too low, are introduced to the energy system. To shorten the start-up time of the gas — steam and conventional blocks, the structure of the basic components of the blocks are changed, e.g. by reducing the diameter of the boiler, the thickness of its wall is also reduced. The attempts were also made to revise the currently binding TRD 301 regulations, replacing them by the EN 12952-3 European Standard, to reduce the allowable heating and cooling rates of thick walled boiler components. The basic assumption, on which the boiler regulations allowing to calculate the allowable temperature change rates of pressure components were based, was the quasi — steady state of the temperature field in the simple shaped component, such as a slab, cylindrical or spherical wall.

  11. A Multiscale Analysis of the Residual Stresses Occurring During Cooling of Thick-Walled Unidirectionally Filament-Wound Cylinders

    NASA Astrophysics Data System (ADS)

    Memarianfard, H.; Turusov, R. A.

    2016-09-01

    A numerical multiscale analysis to predict the residual thermal stresses occurring during cooling in thick-walled filament-wound cylinders made of a reinforced polymer at macro-and microscales is presented. Two types of contact — bonded and unbonded — between the mandrel and the composite are considered. The fields of microstresses are calculated in three different zones across the thickness of the cylinder by using the multiscale finite-element method. Results of the microscale analysis showed that the microstresses several times exceeded the macrostresses in these areas. The value and position of the maximum microstresses were found to depend on the type of contact between the mandrel and the thick-walled cylinder.

  12. Influence of wall thickness and diameter on arterial shear wave elastography: a phantom and finite element study

    NASA Astrophysics Data System (ADS)

    Maksuti, Elira; Bini, Fabiano; Fiorentini, Stefano; Blasi, Giulia; Urban, Matthew W.; Marinozzi, Franco; Larsson, Matilda

    2017-04-01

    Quantitative, non-invasive and local measurements of arterial mechanical properties could be highly beneficial for early diagnosis of cardiovascular disease and follow up of treatment. Arterial shear wave elastography (SWE) and wave velocity dispersion analysis have previously been applied to measure arterial stiffness. Arterial wall thickness (h) and inner diameter (D) vary with age and pathology and may influence the shear wave propagation. Nevertheless, the effect of arterial geometry in SWE has not yet been systematically investigated. In this study the influence of geometry on the estimated mechanical properties of plates (h  =  0.5-3 mm) and hollow cylinders (h  =  1, 2 and 3 mm, D  =  6 mm) was assessed by experiments in phantoms and by finite element method simulations. In addition, simulations in hollow cylinders with wall thickness difficult to achieve in phantoms were performed (h  =  0.5-1.3 mm, D  =  5-8 mm). The phase velocity curves obtained from experiments and simulations were compared in the frequency range 200-1000 Hz and showed good agreement (R 2  =  0.80  ±  0.07 for plates and R 2  =  0.82  ±  0.04 for hollow cylinders). Wall thickness had a larger effect than diameter on the dispersion curves, which did not have major effects above 400 Hz. An underestimation of 0.1-0.2 mm in wall thickness introduces an error 4-9 kPa in hollow cylinders with shear modulus of 21-26 kPa. Therefore, wall thickness should correctly be measured in arterial SWE applications for accurate mechanical properties estimation.

  13. Carotid intima-media wall thickness in elderly women with and without atherosclerosis of the abdominal aorta.

    PubMed

    Bots, M L; Witteman, J C; Grobbee, D E

    1993-08-01

    In the present study the association was evaluated between non-invasively assessed atherosclerosis of the abdominal aorta and ultrasonographically measured intima-media wall thickness of the common carotid arteries in a population-based study of 41 elderly women. Atherosclerosis of the abdominal aorta was assessed in 1985 using a lateral X-ray of the lumbar spine, on which the presence of calcified deposits was determined. The carotid arteries were ultrasonographically evaluated in 1990 for presence of atherosclerotic plaques and intima-media wall thickness of the distal common carotid was measured off line using dedicated software. The age-adjusted mean intima-media wall thickness of the right common carotid artery was significantly higher in subjects with calcified deposits in the aorta (n = 16) compared with those without deposits (n = 25) with a mean difference of 0.15 mm (95% confidence interval (CI) 0.03, 0.26). For the left side similar results were observed. Mean common carotid intima-media wall thickness, ((left+right)/2), differed significantly across groups with a mean difference of 0.11 mm (95% CI 0.01, 021). Additional adjustment for differences across groups in body mass index, serum cholesterol, hypertension and smoking did not change the magnitude of the observed association: mean difference of 0.12 mm (95% CI -0.01, 0.25). The findings of the present study provide evidence that among subjects with atherosclerotic plaques in the abdominal aorta, the intima-media wall thickness of the distal common carotid arteries is increased.

  14. On the use of thick-airfoil theory to design airfoil families in which thickness and lift are varied independently

    NASA Technical Reports Server (NTRS)

    Barger, R. L.

    1974-01-01

    A method has been developed for designing families of airfoils in which the members of a family have the same basic type of pressure distribution but vary in thickness ratio or lift, or both. Thickness ratio and lift may be prescribed independently. The method which is based on the Theodorsen thick-airfoil theory permits moderate variations from the basic shape on which the family is based.

  15. Freedom Station wall design using hydrodynamic modelling. [for meteroroid and space debris impacts

    NASA Technical Reports Server (NTRS)

    Williamsen, Joel E.; Tipton, John P.

    1990-01-01

    The paper outlines selected outputs from an ongoing Marshall Space Flight Center/US Army Corps of Engineers parametric study of the effects of meteoroid/space debris impacts on Space Station Freedom module wall protection structures. The advantages and limitations of HULL hydrocode computer simulation are discussed, and examples of meteoroid/ debris impacts on various wall structural designs are presented. Trends in the terminal effects of particle sizes, velocities, shapes, and impact angles upon structural design parameters (wall and bumper thickness and spacing) are summarized and depicted through selected simulation runs. Throughout the paper, proposed structural modifications to the baseline module protection structure will be examined which are capable of mitigating damage from particle impacts.

  16. Measurement of three-dimensional normal vectors, principal curvatures, and wall thickness of the heart using cine-MRI

    NASA Astrophysics Data System (ADS)

    Coghlan, Leslie; Singleton, H. R.; Dell'Italia, L. J.; Linderholm, C. E.; Pohost, G. M.

    1995-05-01

    We have developed a method for measuring the detailed in vivo three dimensional geometry of the left and right ventricles using cine-magnetic resonance imaging. From data in the form of digitized short axis outlines, the normal vectors, principal curvatures and directions, and wall thickness were computed. The method was evaluated on simulated ellipsoids and on human MRI data. Measurements of normal vectors and of wall thickness were very accurate in simulated data and appeared appropriate in patient data. On simulated data, measurements of the principal curvature k1 (corresponding approximately to the short axis direction of the left ventricle) and of principal directions were quite accurate, but measurements of the other principal curvature (k2) were less accurate. The reasons behind this are considered. We expect improvements in the accuracy with thinner slices and improved representation of the surface data. Gradient echo images were acquired from 8 dogs with a 1.5T system (Philips Gyroscan) at baseline and four months after closed chest experimentally produced mitral regurgitation (MR). The product (k1 + k2) X wall thickness averaged over all slices at end-diastole was significantly lower after surgery (n equals 8, p < 0.005). These geometry changes were consistent with the expected increase in wall stress after MR.

  17. Fusion Engineering Device (FED) first wall/shield design

    SciTech Connect

    Sager, P.H.; Fuller, G.; Cramer, B.; Davisson, J.; Haines, J.; Kirchner, J.

    1981-01-01

    The torus of the Fusion Engineering Device (FED) is comprised of the bulk shield and its associated spool lstructure and support system, the first wall water-cooled panel and armor systems, and the pumped limiter. The bulk shielding is provided by ten shield sectors that are installed in the spool structure in such a way as to permit extraction of the sectors through the openings between adjacent toroidal field coils with a direct radial movement. The first wall armor is installed on the inboard and top interior walls of these sectors, and the water-cooled panels are installed on the outboard interior walls and the pumped limiter in the bottom of the sectors. The overall design of the first wall and shield system is described in this paper.

  18. Pressure-induced wall thickness variations in multi-layered wall of a pollen tube and Fourier decomposition of growth oscillations.

    PubMed

    Pietruszka, Mariusz; Haduch-Sendecka, Aleksandra

    2015-04-01

    The augmented growth equation introduced by Ortega is solved for the apical portion of the pollen tube as an oscillating volume, which we approach in the framework of a two-fluid model in which the two fluids represent the constant pressure and the fluctuating features of the system. Based on routine Fourier analysis, we calculate the energy spectrum of the oscillating pollen tube, and discuss the resonant frequency problem of growth rate oscillations. We also outline a descriptive model for cell wall thickness fluctuations associated with small, yet regular variations (~ 0.01 MPa) observed in turgor pressure. We propose that pressure changes must lead to the sliding of wall layers, indirectly resulting in a wave of polarization of interlayer bonds. We conclude that pollen tube wall thickness may oscillate due to local variations in cell wall properties and relaxation processes. These oscillations become evident because of low amplitude/high frequency pressure fluctuations δP being superimposed on turgor pressure P. We also show that experimentally determined turgor pressure oscillates in a strict periodical manner. A solitary frequency f0 ≈ 0.066 Hz of these (~ 0.01 MPa in magnitude) oscillations for lily pollen tubes was established by the discrete Fourier transform and Lorentz fit.

  19. The Relationship of Educational Attainment with Pulmonary Emphysema and Airway Wall Thickness.

    PubMed

    Gjerdevik, Miriam; Grydeland, Thomas B; Washko, George R; Coxson, Harvey O; Silverman, Edwin K; Gulsvik, Amund; Bakke, Per S

    2015-06-01

    Low educational attainment is a risk factor of chronic obstructive pulmonary disease (COPD). There is limited knowledge on the relationship between educational level and computed tomography measures of emphysema and airway wall thickness (AWT). We hypothesized that low educational attainment is associated with increased emphysema and AWT in ever-smokers with and without COPD. We included 462 and 485 ever-smokers with and without COPD in a cross-sectional study, aged 40-86 years. The sample was divided into groups reflecting educational attainment: primary, secondary, and university. We performed linear regression to examine associations between educational attainment and both emphysema and AWT separately for those with and without COPD. We adjusted for sex, age, smoking status, age of onset of smoking, pack-years, height, and body mass index. Compared with university education, in subjects with COPD, primary education was associated with a 68.1% (95% confidence interval = 14.2-147.6%; P = 0.01) relative increase in emphysema and secondary education was associated with a 50.6% (95% confidence interval = 5.7-114.6%; P = 0.02) relative increase. There was a nonsignificant trend toward an association between lower educational attainment and increased emphysema among those without COPD (P = 0.18), yet greater age appeared to modify this association (P = 0.01). We did not detect significant linear relationships between educational attainment and AWT in subjects with or without COPD. Lower educational attainment was associated with increased emphysema among adults with COPD. Among those without COPD, this association was more pronounced with increasing age. No significant linear relationship between educational attainment and AWT was found. Clinicians treating adults with emphysema should keep in mind that factors related to low education beyond that of smoking and occupational dust exposure might be of importance to the disease.

  20. Charged magnetic domain walls as observed in nanostructured thin films: dependence on both film thickness and anisotropy.

    PubMed

    Favieres, C; Vergara, J; Madurga, V

    2013-02-13

    The magnetic domain configurations of soft magnetic, nanostructured, pulsed laser-deposited Co films were investigated. Their dependence on both the thickness t (20 nm ≤ t ≤ 200 nm) and the anisotropy was studied. Charged zigzag walls, with a characteristic saw-tooth vertex angle θ, were observed. θ changed with t from θ ≈ 17° to ≈25°, presenting an intermediate sharp maximum that has not been described before. The reduced length of the zigzag walls also exhibited a peak at t ≈ 70 nm. The relationship between the total reduced length and the density energy of the magnetic wall allowed us to establish a change from a Néel-type to a Bloch-type core of the zigzag walls at this thickness, t ≈ 70 nm. We also accounted for the magnetic energy arising from the surface roughness of the thinner films after imaging the film surface morphologies. Moreover, this distinctive behaviour of the zigzag walls of these low-anisotropy films was compared to that of high-anisotropy films.

  1. Biometric estimation of chest wall thickness of female radiation workers as an aid in in-vivo detection of the actinides

    SciTech Connect

    Lane, B.H.; Berger, C.D.

    1983-01-01

    An equation was derived to estimate female chest wall thickness from a series of biometric measurements. This technique will result in improved performance for actinide detection in females by accounting for variations in chest wall thickness in derivation of calibration factors.

  2. Transpiring wall supercritical water oxidation test reactor design report

    SciTech Connect

    Haroldsen, B.L.; Ariizumi, D.Y.; Mills, B.E.; Brown, B.G.; Rousar, D.C.

    1996-02-01

    Sandia National Laboratories is working with GenCorp, Aerojet and Foster Wheeler Development Corporation to develop a transpiring wall supercritical water oxidation reactor. The transpiring wall reactor promises to mitigate problems of salt deposition and corrosion by forming a protective boundary layer of pure supercritical water. A laboratory scale test reactor has been assembled to demonstrate the concept. A 1/4 scale transpiring wall reactor was designed and fabricated by Aerojet using their platelet technology. Sandia`s Engineering Evaluation Reactor serves as a test bed to supply, pressurize and heat the waste; collect, measure and analyze the effluent; and control operation of the system. This report describes the design, test capabilities, and operation of this versatile and unique test system with the transpiring wall reactor.

  3. Optimal Design of Sheet Pile Wall Embedded in Clay

    NASA Astrophysics Data System (ADS)

    Das, Manas Ranjan; Das, Sarat Kumar

    2015-09-01

    Sheet pile wall is a type of flexible earth retaining structure used in waterfront offshore structures, river protection work and temporary supports in foundations and excavations. Economy is an essential part of a good engineering design and needs to be considered explicitly in obtaining an optimum section. By considering appropriate embedment depth and sheet pile section it may be possible to achieve better economy. This paper describes optimum design of both cantilever and anchored sheet pile wall penetrating clay using a simple optimization tool Microsoft Excel ® Solver. The detail methodology and its application with examples are presented for cantilever and anchored sheet piles. The effects of soil properties, depth of penetration and variation of ground water table on the optimum design are also discussed. Such a study will help professional while designing the sheet pile wall penetrating clay.

  4. Finite-element modelling of low-temperature autofrettage of thick-walled tubes of the austenitic stainless steel AISI 304 L: Part II. Thick-walled tube with cross-bore

    NASA Astrophysics Data System (ADS)

    Feng, H.; Donth, B.; Mughrabi, H.

    1998-01-01

    In part I, the autofrettage of a smooth thick-walled tube of the austenitic stainless steel AISI 304 L was studied by finite-element (FE) modelling. It was shown that low- temperature autofrettage is more efficient than autofrettage at room temperature, since it produces a larger beneficial compressive residual tangential (hoop) stress at the inner bore of the tube and hence permits a more significant enhancement of the fatigue resistance against pulsating internal pressure. The objective of the present study (part II) was to investigate the technically more relevant case of a thick-walled tube with a cross-bore made of the same steel. For this purpose, three-dimensional FE calculations were performed in order to characterize the influences of the autofrettage pressure and temperature on the stress and strain changes, in particular at the site of the cross-bore, also taking into account the effects of work hardening and reverse yielding. The results indicate that low-temperature autofrettage can also be applied advantageously in the case of thick-walled tubes with a cross-bore by virtue of the significantly larger residual compressive stresses, compared to room temperature autofrettage. From the quantitative FE calculations, the optimal combination of autofrettage temperature and pressure were concluded to lie in the range of 0965-0393/6/1/007/img1 to 0965-0393/6/1/007/img2, respectively. The calculated results were found to be in fair agreement with the measured values.

  5. Enhanced film thickness for Néel wall in soft magnetic film by introducing strong magnetocrystalline anisotropy.

    PubMed

    Xu, Fei; Wang, Tao; Ma, Tianyong; Wang, Ying; Zhu, Shimeng; Li, Fashen

    2016-01-29

    This study investigated the magnetic domain walls in a single-layer soft magnetic film with strong magnetocrystalline anisotropy energy. The soft magnetic film is composed of a highly c-axis-oriented hcp-Co81Ir19 alloy with strong negative magnetocrystalline anisotropy. The domain structure of the soft Co81Ir19 films with thickness ranging from 50-230 nm in a demagnetization state was observed through magnetic force microscopy and Lorentz transmission electron microscopy. Results reveal that the critical transition thickness at which the domain wall changes from Néel type to Bloch type is about 138 nm, which is much larger than the critical value of traditional Fe- and Co-based soft magnetic films with negligible magnetocrystalline anisotropy. Theoretical calculation was also performed and the calculated result agrees well with experimental data.

  6. Enhanced film thickness for Néel wall in soft magnetic film by introducing strong magnetocrystalline anisotropy

    NASA Astrophysics Data System (ADS)

    Xu, Fei; Wang, Tao; Ma, Tianyong; Wang, Ying; Zhu, Shimeng; Li, Fashen

    2016-01-01

    This study investigated the magnetic domain walls in a single-layer soft magnetic film with strong magnetocrystalline anisotropy energy. The soft magnetic film is composed of a highly c-axis-oriented hcp-Co81Ir19 alloy with strong negative magnetocrystalline anisotropy. The domain structure of the soft Co81Ir19 films with thickness ranging from 50-230 nm in a demagnetization state was observed through magnetic force microscopy and Lorentz transmission electron microscopy. Results reveal that the critical transition thickness at which the domain wall changes from Néel type to Bloch type is about 138 nm, which is much larger than the critical value of traditional Fe- and Co-based soft magnetic films with negligible magnetocrystalline anisotropy. Theoretical calculation was also performed and the calculated result agrees well with experimental data.

  7. Enhanced film thickness for Néel wall in soft magnetic film by introducing strong magnetocrystalline anisotropy

    PubMed Central

    Xu, Fei; Wang, Tao; Ma, Tianyong; Wang, Ying; Zhu, Shimeng; Li, Fashen

    2016-01-01

    This study investigated the magnetic domain walls in a single-layer soft magnetic film with strong magnetocrystalline anisotropy energy. The soft magnetic film is composed of a highly c-axis-oriented hcp-Co81Ir19 alloy with strong negative magnetocrystalline anisotropy. The domain structure of the soft Co81Ir19 films with thickness ranging from 50–230 nm in a demagnetization state was observed through magnetic force microscopy and Lorentz transmission electron microscopy. Results reveal that the critical transition thickness at which the domain wall changes from Néel type to Bloch type is about 138 nm, which is much larger than the critical value of traditional Fe- and Co-based soft magnetic films with negligible magnetocrystalline anisotropy. Theoretical calculation was also performed and the calculated result agrees well with experimental data. PMID:26821614

  8. Fusion of fibrous cap thickness and wall shear stress to assess plaque vulnerability in coronary arteries: a pilot study.

    PubMed

    Zahnd, Guillaume; Schrauwen, Jelle; Karanasos, Antonios; Regar, Evelyn; Niessen, Wiro; van Walsum, Theo; Gijsen, Frank

    2016-10-01

    Identification of rupture-prone plaques in coronary arteries is a major clinical challenge. Fibrous cap thickness and wall shear stress are two relevant image-based risk factors, but these two parameters are generally computed and analyzed separately. Accordingly, combining these two parameters can potentially improve the identification of at-risk regions. Therefore, the purpose of this study is to investigate the feasibility of the fusion of wall shear stress and fibrous cap thickness of coronary arteries in patient data. Fourteen patients were included in this pilot study. Imaging of the coronary arteries was performed with optical coherence tomography and with angiography. Fibrous cap thickness was automatically quantified from optical coherence tomography pullbacks using a contour segmentation approach based on fast marching. Wall shear stress was computed by applying computational fluid dynamics on the 3D volume reconstructed from two angiograms. The two parameters then were co-registered using anatomical landmarks such as side branches. The two image modalities were successfully co-registered, with a mean (±SD) error corresponding to [Formula: see text] of the length of the analyzed region. For all the analyzed participants, the average thinnest portion of each fibrous cap was [Formula: see text], and the average WSS value at the location of the fibrous cap was [Formula: see text]. A unique index was finally generated for each patient via the fusion of fibrous cap thickness and wall shear stress measurements, to translate all the measured parameters into a single risk map. The introduced risk map integrates two complementary parameters and has potential to provide valuable information about plaque vulnerability.

  9. Chest-wall thickness and percent thoracic fat estimation by B-mode ultrasound: system and procedure review

    SciTech Connect

    Berger, C.D.; Lane, B.H.; Dunsmore, M.R.

    1983-02-01

    Accurate measurement of chest wall thickness is necessary for estimation of lung burden of transuranic elements in humans. To achieve tis capability, the ORNL Whole Body Counter has acquired a B-mode ultrasonic imaging system for defining the structure within the thorax of the body. This report contains a review of the ultrasound system in use at the ORNL Whole Body Counter, including its theory of operation, and te procedure for use of the system. Future developmental plans are also presented.

  10. [Inconsistency between voltage of the electrocardiogram and the left ventricular wall thickness. diagnostic key in cardiac amyloidosis].

    PubMed

    Contreras, A; Beacon, E; Brenna, Eduardo J; Parisi, Gustavo R; Chamale, Roberto A; Gilardi, F; Bürguesser, M V; Salomone, O

    2013-01-01

    Restrictive cardiomyopathy is the least common form of cardiomyopathy, and the disease that most often cause it, is the system amyloidosis. We present a 62-year-old with a history of heart failure, which in its assessment highlights the discrepancy between the low voltage ventricular complexes in the electrocardiogram and the severity of left ventricular wall thickness on echocardiography. This discrepancy was the source of suspicion and subsequent confirmation of systemic amyloidosis with cardiac involvement.

  11. Airway wall thickness of allergic asthma caused by weed pollen or house dust mite assessed by computed tomography.

    PubMed

    Liu, Liping; Li, Guangrun; Sun, Yuemei; Li, Jian; Tang, Ningbo; Dong, Liang

    2015-03-01

    Little was known about Airway wall thickness of asthma patients with different allergen allergy. So we explored the possible difference of Airway wall thickness of asthma patients mono-sensitized to weed pollen or HDM using high-resolution computed tomography. 85 severe asthma patients were divided into weed pollen group and HDM group according to relevant allergen. 20 healthy donors served as controls. Airway wall area, percentage wall area and luminal area at the trunk of the apical bronchus of the right upper lobe were quantified using HRCT and compared. The values of pulmonary function were assessed as well. There were differences between HDM group and weed pollen group in WA/BSA,WA% and FEF25-75% pred, and no significant difference in FEV1%pred, FEV1/FVC and LA/BSA. In weed pollen group, WA/BSA was observed to correlate with the duration of rhinitis, whereas in HDM group, WA/BSA and LA/BSA was observed to correlate with the duration of asthma. In weed pollen group, FEV1/FVC showed a weak but significant negative correlation with WA%, but in HDM group FEV1/FVC showed a significant positive correlation with WA% and a statistical negative correlation with LA/BSA. FEV1/FVC and FEF25-75% pred were higher and WA/BSA and LA/BSA were lower in healthy control group than asthma group. FEV1%pred and WA% was no significant difference between asthma patients and healthy subjects. There are differences between HDM mono-sensitized subjects and weed pollen mono-sensitized subjects, not only in airway wall thickness, but also small airway obstruction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Anticipatory extended cholecystectomy: the 'Lucknow' approach for thick walled gall bladder with low suspicion of cancer.

    PubMed

    Kapoor, Vinay K; Singh, Rakesh; Behari, Anu; Sharma, Supriya; Kumar, Ashok; Prakash, Anand; Singh, Rajneesh Kumar; Kumar, Ashok; Saxena, Rajan

    2016-02-01

    Gall stones (GS) cause inflammation of the gall bladder (GB) i.e., chronic cholecystitis (CC) and xantho-granulomatous cholecystitis (XGC) which can result in a thick walled GB (TWGB). Gall bladder cancer (GBC) may also present as TWGB. While CC and XGC can be treated with simple cholecystectomy (SC), GBC merits extended cholecystectomy (EC). We propose a new surgical approach, anticipatory extended cholecystectomy (AEC), for doubtful TWGB in the belief that AEC would not violate the sacrosanct cholecysto-hepatic plane in doubtful cases and thereby not ruin the chances of cure for a patient whose GB demonstrates malignancy on frozen section histopathology. The addition of lymphadenectomy in cases which turn out to be malignant completes the procedure for GB cancer, but spares all problems related to lymphadenectomy in an undeserving patient. AEC involves removal of GB with a 2-cm wedge of liver, which is then subjected to frozen section histological examination. Lymphadenectomy is performed if GBC is confirmed. AEC was performed in 13 patients between January 2011 and June 2014. During the same period, 1,673 SC for CC/XGC and 116 EC for GBC were performed. All patients were symptomatic for GS (3 with acute cholecystitis). Ultrasonography (US) raised suspicion of GBC in 11 patients. CT raised suspicion of GBC in 9 patients. Preoperative FNAC was done in 2 patients; in 1 it was negative and in 1 it was suspicious for malignancy. Preoperative diagnosis was GBC in 8, TWGB in 2, XGC, porcelain GB and GB perforation in 1 each. AEC and frozen section was done in all 13 patients. It was reported as GBC in 2 patients and as suspicious of GBC in 1 patient; lymphadenectomy was performed in these 3 patients. Final histopathology revealed XGC in 9, CC in 2 and GBC in 2 patients. In patients with TWGB on US/ CT with low suspicion of cancer, AEC serves as a triage-if frozen section biopsy turns out to be positive for GBC, AEC can be completed to EC by performing lymphadenectomy

  13. Thermal insulating concrete wall panel design for sustainable built environment.

    PubMed

    Zhou, Ao; Wong, Kwun-Wah; Lau, Denvid

    2014-01-01

    Air-conditioning system plays a significant role in providing users a thermally comfortable indoor environment, which is a necessity in modern buildings. In order to save the vast energy consumed by air-conditioning system, the building envelopes in envelope-load dominated buildings should be well designed such that the unwanted heat gain and loss with environment can be minimized. In this paper, a new design of concrete wall panel that enhances thermal insulation of buildings by adding a gypsum layer inside concrete is presented. Experiments have been conducted for monitoring the temperature variation in both proposed sandwich wall panel and conventional concrete wall panel under a heat radiation source. For further understanding the thermal effect of such sandwich wall panel design from building scale, two three-story building models adopting different wall panel designs are constructed for evaluating the temperature distribution of entire buildings using finite element method. Both the experimental and simulation results have shown that the gypsum layer improves the thermal insulation performance by retarding the heat transfer across the building envelopes.

  14. Thermal Insulating Concrete Wall Panel Design for Sustainable Built Environment

    PubMed Central

    Zhou, Ao; Wong, Kwun-Wah

    2014-01-01

    Air-conditioning system plays a significant role in providing users a thermally comfortable indoor environment, which is a necessity in modern buildings. In order to save the vast energy consumed by air-conditioning system, the building envelopes in envelope-load dominated buildings should be well designed such that the unwanted heat gain and loss with environment can be minimized. In this paper, a new design of concrete wall panel that enhances thermal insulation of buildings by adding a gypsum layer inside concrete is presented. Experiments have been conducted for monitoring the temperature variation in both proposed sandwich wall panel and conventional concrete wall panel under a heat radiation source. For further understanding the thermal effect of such sandwich wall panel design from building scale, two three-story building models adopting different wall panel designs are constructed for evaluating the temperature distribution of entire buildings using finite element method. Both the experimental and simulation results have shown that the gypsum layer improves the thermal insulation performance by retarding the heat transfer across the building envelopes. PMID:25177718

  15. Stoichiometry, Length, and Wall Thickness Optimization of TiO2 Nanotube Array for Efficient Alcohol Sensing.

    PubMed

    Hazra, A; Bhowmik, B; Dutta, K; Chattopadhyay, P P; Bhattacharyya, P

    2015-05-13

    The present study concerns development of an efficient alcohol sensor by controlling the stoichiometry, length, and wall thickness of electrochemically grown TiO2 nanotube array for its use as the sensing layer. Judicious variation of H2O content (0, 2, 10 and 100% by volume) in the mixed electrolyte comprising ethylene glycol and NH4F resulted into the desired variation of stoichiometry. The sensor study was performed within the temperature range of 27 to 250 °C for detecting the alcohols in the concentration range of 10-1000 ppm. The nanotubes grown with the electrolyte containing 2 vol % H2O offered the maximum response magnitude. For this stoichiometry, variation of corresponding length (1.25-2.4 μm) and wall thickness (19.8-9 nm) of the nanotubes was achieved by varying the anodization time (4-16 h) and temperatures (42-87 °C), respectively. While the variation of length influenced the sensing parameters insignificantly, the best response magnitude was achieved for ∼13 nm wall thickness. The underlying sensing mechanism was correlated with the experimental findings on the basis of structural parameters of the nanotubes.

  16. Dimensionless analysis of valveless pumping in a thick-wall elastic tube: Application to the tubular embryonic heart.

    PubMed

    Kozlovsky, Pavel; Rosenfeld, Moshe; Jaffa, Ariel J; Elad, David

    2015-06-25

    The physical mechanism that drives blood flow in the valveless tubular embryonic heart is still debatable whether it is peristaltic flow or valveless dynamic suction. Previous studies of valveless pumping were concerned with either the role of the excitation parameters or the mechanisms that generate the unidirectional outflow. In this study, a dimensionless one-dimensional (1D) analysis of the valveless pumping due to local excitation at an asymmetric longitudinal location was performed for non-uniform thick-wall elastic tubes, including tubes with local bulging and tapering. A general tube law that accounts for wall thicknesses was implemented for describing the physically realistic dynamics of the tube and the two-step MacCormack algorithm was utilized for the numerical analysis. A comprehensive analysis was conducted to explore the affecting roles of the system (e.g., tube geometry) and the working (e.g., Strouhal number and flow friction parameter) parameters on the net outflow of the pump. The maximal positive net outflow in all the tested cases always occurred when the natural Strouhal number was about π. Flow reversals were observed only for relatively low friction parameters. A local bulging at the site of excitation and thick walls contributed to larger outflows, while tube tapering reduced the net outflow.

  17. Assessment of seismic design response factors of concrete wall buildings

    NASA Astrophysics Data System (ADS)

    Mwafy, Aman

    2011-03-01

    To verify the seismic design response factors of high-rise buildings, five reference structures, varying in height from 20- to 60-stories, were selected and designed according to modern design codes to represent a wide range of concrete wall structures. Verified fiber-based analytical models for inelastic simulation were developed, considering the geometric nonlinearity and material inelasticity of the structural members. The ground motion uncertainty was accounted for by employing 20 earthquake records representing two seismic scenarios, consistent with the latest understanding of the tectonic setting and seismicity of the selected reference region (UAE). A large number of Inelastic Pushover Analyses (IPAs) and Incremental Dynamic Collapse Analyses (IDCAs) were deployed for the reference structures to estimate the seismic design response factors. It is concluded that the factors adopted by the design code are adequately conservative. The results of this systematic assessment of seismic design response factors apply to a wide variety of contemporary concrete wall buildings with various characteristics.

  18. Diffusion capacity and CT measures of emphysema and airway wall thickness – relation to arterial oxygen tension in COPD patients

    PubMed Central

    Saure, Eirunn Waatevik; Bakke, Per Sigvald; Eagan, Tomas Mikal Lind; Aanerud, Marianne; Jensen, Robert Leroy; Grydeland, Thomas Blix; Johannessen, Ane; Nilsen, Roy Miodini; Thorsen, Einar; Hardie, Jon Andrew

    2016-01-01

    Background Decreased diffusing capacity of the lung for carbon monoxide (DLCO) is associated with emphysema. DLCO is also related to decreased arterial oxygen tension (PaO2), but there are limited data on associations between PaO2 and computed tomography (CT) derived measures of emphysema and airway wall thickness. Objective To examine whether CT measures of emphysema and airway wall thickness are associated with level of arterial oxygen tension beyond that provided by measurements of diffusion capacity and spirometry. Methods The study sample consisted of 271 smoking or ex-smoking COPD patients from the Bergen COPD Cohort Study examined in 2007–2008. Emphysema was assessed as percent of low-attenuation areas<−950 Hounsfield units (%LAA), and airway wall thickness as standardised measure at an internal perimeter of 10 mm (AWT-Pi10). Multiple linear regression models were fitted with PaO2 as the outcome variable, and %LAA, AWT-Pi10, DLCO and carbon monoxide transfer coefficient (KCO) as main explanatory variables. The models were adjusted for sex, age, smoking status, and haemoglobin concentration, as well as forced expiratory volume in one second (FEV1). Results Sixty two per cent of the subjects were men, mean (SD) age was 64 (7) years, mean (SD) FEV1 in percent predicted was 50 (15)%, and mean PaO2 (SD) was 9.3 (1.1) kPa. The adjusted regression coefficient (CI) for PaO2 was –0.32 (−0.04–(−0.019)) per 10% increase in %LAA (p<0.01). When diffusion capacity and FEV1 were added to the model, respectively, the association lost its statistical significance. No relationship between airway wall thickness and PaO2 was found. Conclusion CT assessment of airway wall thickness is not associated with arterial oxygen tension in COPD patients. Emphysema score measured by chest CT, is related to decreased PaO2, but cannot replace measurements of diffusion capacity in the clinical evaluation of hypoxaemia. PMID:27178139

  19. Riser Difference Evaluation from Ultrasonic Wall Thickness Inspection of Thirteen Double-Shell Tanks

    SciTech Connect

    Weier, Dennis R.; Pardini, Allan F.

    2010-03-15

    PNNL has performed an analysis of ultrasonic thickness measurements taken on Hanford's double-shell tanks (DSTs) approximately eight years apart. The analysis was performed to determine whether significant differences exist between ultrasonic thickness measurements made in two opposite risers in Hanford DSTs that have been examined twice.

  20. A novel solution for LED wall lamp design and simulation

    NASA Astrophysics Data System (ADS)

    Ge, Rui; Hong, Weibin; Li, Kuangqi; Liang, Pengxiang; Zhao, Fuli

    2014-11-01

    The model of the wall washer lamp and the practical illumination application have been established with a new design of the lens to meet the uniform illumination demand for wall washer lamp based on the Lambertian light sources. Our secondary optical design of freeform surface lens to LED wall washer lamp based on the conservation law of energy and Snell's law can improve the lighting effects as a uniform illumination. With the relationship between the surface of the lens and the surface of the target, a great number of discrete points of the freeform profile curve were obtained through the iterative method. After importing the data into our modeling program, the optical entity was obtained. Finally, to verify the feasibility of the algorithm, the model was simulated by specialized software, with both the LED Lambertian point source and LED panel source model.

  1. Thickness-dependent domain wall reorientation in 70/30 lead magnesium niobate- lead titanate thin films

    DOE PAGES

    Keech, Ryan; Morandi, Carl; Wallace, Margeaux; ...

    2017-04-11

    Continued reduction in length scales associated with many ferroelectric film-based technologies is contingent on retaining the functional properties as the film thickness is reduced. Epitaxial and polycrystalline lead magnesium niobate - lead titanate (70PMN-30PT) thin films were studied over the thickness range of 100-350 nm for the relative contributions to property thickness dependence from interfacial and grain boundary low permittivity layers. Epitaxial PMN-PT films were grown on SrRuO3 /(001)SrTiO3, while polycrystalline films with {001}-Lotgering factors >0.96 were grown on Pt/TiO2/SiO2/Si substrates via chemical solution deposition. Both film types exhibited similar relative permittivities of ~300 at high fields at all measuredmore » thicknesses with highly crystalline electrode/dielectric interfaces. These results, with the DC-biased and temperature dependent dielectric characterization, suggest irreversible domain wall mobility is the major contributor to the overall dielectric response and its thickness dependence. In epitaxial films, the irreversible Rayleigh coefficients reduced 85% upon decreasing thickness from 350 to 100 nm. The temperature at which a peak in the relative permittivity is observed was the only measured small signal quantity which was more thickness dependent in polycrystalline than epitaxial films. This is attributed to the relaxor nature present in the films, potentially stabilized by defect concentrations, and/or chemical inhomogeneity. Finally, the effective interfacial layers are found to contribute to the measured thickness dependence in the longitudinal piezoelectric coefficient.« less

  2. Computer simulation of the precordial QRS complex: effects of simulated changes in ventricular wall thickness and volume.

    PubMed

    Salu, Y; Marcus, M L

    1976-12-01

    The cardiac electric field generated by depolarization of the human ventricle is simulated with a computer model which utilizes 1,500 dipoles. The configuration of the ventricles utilized in the model assumed that the cross-sectional shape of the left ventricle was circular and the right ventricular free wall was a portion of an ellipse. The torso was assumed to be homogeneous and infinite. The activation sequence was based on the measurements of Durrer. The depolarizational wave was simulated by dipole layers. The output of the model is presented as a standard multilead precordial ECG. The ECG complexes generated by the model closely resemble the precordial QRS complexes of normal man. Simulated increases in wall thickness (1 to 2.2 X control) were associated with changes in the calculated precordial QRS complexes which were characteristic of left ventricular hypertrophy. Voltage (R in V5 or V6 and S in V1) and QRS duration increased linearly as a function of calculated left ventricular mass. Increases in ventricular activation time were related nonlinearly to changes in left ventricular mass and did not occur in the absence of a simulated increase in wall thickness. The effects of simulated changes in left ventricular volume (0.6 to 3.0 X control) on the QRS complex were mainly dependent on the resultant increase in left ventricular mass. This model may be useful in simulating the precordial QRS complexes that result from isolated or combined changes in ventricular volume or wall thickness or other disorders of the heart. Furthermore, it may be useful whenever a simulation of a QRS generator is needed.

  3. Working stress design method for reinforced soil walls

    SciTech Connect

    Ehrlich, M. ); Mitchell, J.K. )

    1994-04-01

    A method for the internal design of reinforced soil walls based on working stresses is developed and evaluated using measurements from five full-scale structures containing a range of reinforcement types. It is shown that, in general, the stiffer the reinforcement system and the higher the stresses induced during compaction, the higher are the tensile stresses that must be resisted by the reinforcements. Unique features of this method, compared to currently used reinforced soil wall design methods, are that it can be applied to all types of reinforcement systems, reinforcement and soil stiffness properties are considered, and backfill compaction stresses are taken explicitly into account. The method can be applied either analytically or using design charts. A design example is included.

  4. First wall-shield design considerations for ETF

    SciTech Connect

    Sager, P.H.; Fuller, G.M.; Engholm, B.A.

    1980-01-01

    ETF reactor designs have been developed for both the bundle divertor (Design 1) and single-null poloidal divertor (Design 2) impurity control concepts. The first wall-shield designs presented for these two reactors are basically the same. Access for repair and replacement is provided by dividing the torus into ten sectors that can be radially removed between adjacent toroidal field (TF) coils. Stainless steel, cooled by borated water, forms the basic structure of these sectors. Water-cooled tube panels, radiation-cooled graphite disruption armor, and water-cooled grraphite runaway electron armor are attached to the inside walls of these sectors to form the plasma chamber. The torus sectors are mounted to and form a vacuum seal with a torus support spool.

  5. Development of automated welding process for field fabrication of thick walled pressure vessels

    SciTech Connect

    Schneider, R.A.

    1981-01-01

    Four tasks are repoted on: review of welding processes (complete), adaptation of the GTAW-HW narrow groove process to vertical and horizontal welds, 8-inch thick field demonstration/qualification welds, and welding procedure handbook. (DLC)

  6. Large-scale, thick, self-assembled, nacre-mimetic brick-walls as fire barrier coatings on textiles

    NASA Astrophysics Data System (ADS)

    Das, Paramita; Thomas, Helga; Moeller, Martin; Walther, Andreas

    2017-01-01

    Highly loaded polymer/clay nanocomposites with layered structures are emerging as robust fire retardant surface coatings. However, time-intensive sequential deposition processes, e.g. layer-by-layer strategies, hinders obtaining large coating thicknesses and complicates an implementation into existing technologies. Here, we demonstrate a single-step, water-borne approach to prepare thick, self-assembling, hybrid fire barrier coatings of sodium carboxymethyl cellulose (CMC)/montmorillonite (MTM) with well-defined, bioinspired brick-wall nanostructure, and showcase their application on textile. The coating thickness on the textile is tailored using different concentrations of CMC/MTM (1–5 wt%) in the coating bath. While lower concentrations impart conformal coatings of fibers, thicker continuous coatings are obtained on the textile surface from highest concentration. Comprehensive fire barrier and fire retardancy tests elucidate the increasing fire barrier and retardancy properties with increasing coating thickness. The materials are free of halogen and heavy metal atoms, and are sourced from sustainable and partly even renewable building blocks. We further introduce an amphiphobic surface modification on the coating to impart oil and water repellency, as well as self-cleaning features. Hence, our study presents a generic, environmentally friendly, scalable, and one-pot coating approach that can be introduced into existing technologies to prepare bioinspired, thick, fire barrier nanocomposite coatings on diverse surfaces.

  7. Large-scale, thick, self-assembled, nacre-mimetic brick-walls as fire barrier coatings on textiles

    PubMed Central

    Das, Paramita; Thomas, Helga; Moeller, Martin; Walther, Andreas

    2017-01-01

    Highly loaded polymer/clay nanocomposites with layered structures are emerging as robust fire retardant surface coatings. However, time-intensive sequential deposition processes, e.g. layer-by-layer strategies, hinders obtaining large coating thicknesses and complicates an implementation into existing technologies. Here, we demonstrate a single-step, water-borne approach to prepare thick, self-assembling, hybrid fire barrier coatings of sodium carboxymethyl cellulose (CMC)/montmorillonite (MTM) with well-defined, bioinspired brick-wall nanostructure, and showcase their application on textile. The coating thickness on the textile is tailored using different concentrations of CMC/MTM (1–5 wt%) in the coating bath. While lower concentrations impart conformal coatings of fibers, thicker continuous coatings are obtained on the textile surface from highest concentration. Comprehensive fire barrier and fire retardancy tests elucidate the increasing fire barrier and retardancy properties with increasing coating thickness. The materials are free of halogen and heavy metal atoms, and are sourced from sustainable and partly even renewable building blocks. We further introduce an amphiphobic surface modification on the coating to impart oil and water repellency, as well as self-cleaning features. Hence, our study presents a generic, environmentally friendly, scalable, and one-pot coating approach that can be introduced into existing technologies to prepare bioinspired, thick, fire barrier nanocomposite coatings on diverse surfaces. PMID:28054589

  8. Large-scale, thick, self-assembled, nacre-mimetic brick-walls as fire barrier coatings on textiles.

    PubMed

    Das, Paramita; Thomas, Helga; Moeller, Martin; Walther, Andreas

    2017-01-05

    Highly loaded polymer/clay nanocomposites with layered structures are emerging as robust fire retardant surface coatings. However, time-intensive sequential deposition processes, e.g. layer-by-layer strategies, hinders obtaining large coating thicknesses and complicates an implementation into existing technologies. Here, we demonstrate a single-step, water-borne approach to prepare thick, self-assembling, hybrid fire barrier coatings of sodium carboxymethyl cellulose (CMC)/montmorillonite (MTM) with well-defined, bioinspired brick-wall nanostructure, and showcase their application on textile. The coating thickness on the textile is tailored using different concentrations of CMC/MTM (1-5 wt%) in the coating bath. While lower concentrations impart conformal coatings of fibers, thicker continuous coatings are obtained on the textile surface from highest concentration. Comprehensive fire barrier and fire retardancy tests elucidate the increasing fire barrier and retardancy properties with increasing coating thickness. The materials are free of halogen and heavy metal atoms, and are sourced from sustainable and partly even renewable building blocks. We further introduce an amphiphobic surface modification on the coating to impart oil and water repellency, as well as self-cleaning features. Hence, our study presents a generic, environmentally friendly, scalable, and one-pot coating approach that can be introduced into existing technologies to prepare bioinspired, thick, fire barrier nanocomposite coatings on diverse surfaces.

  9. Automatic airway wall segmentation and thickness measurement for long-range optical coherence tomography images.

    PubMed

    Qi, Li; Huang, Shenghai; Heidari, Andrew E; Dai, Cuixia; Zhu, Jiang; Zhang, Xuping; Chen, Zhongping

    2015-12-28

    We present an automatic segmentation method for the delineation and quantitative thickness measurement of multiple layers in endoscopic airway optical coherence tomography (OCT) images. The boundaries of the mucosa and the sub-mucosa layers are accurately extracted using a graph-theory-based dynamic programming algorithm. The algorithm was tested with sheep airway OCT images. Quantitative thicknesses of the mucosal layers are obtained automatically for smoke inhalation injury experiments.

  10. Automatic airway wall segmentation and thickness measurement for long-range optical coherence tomography images

    PubMed Central

    Qi, Li; Huang, Shenghai; Heidari, Andrew E.; Dai, Cuixia; Zhu, Jiang; Zhang, Xuping; Chen, Zhongping

    2015-01-01

    We present an automatic segmentation method for the delineation and quantitative thickness measurement of multiple layers in endoscopic airway optical coherence tomography (OCT) images. The boundaries of the mucosa and the sub-mucosa layers are accurately extracted using a graph-theory-based dynamic programming algorithm. The algorithm was tested with sheep airway OCT images. Quantitative thicknesses of the mucosal layers are obtained automatically for smoke inhalation injury experiments. PMID:26832057

  11. Stress-intensity factors for a thick-walled cylinder containing an annular imbedded or external or internal surface crack

    NASA Technical Reports Server (NTRS)

    Erdol, R.; Erdogan, F.

    1976-01-01

    The elastostatic axisymmetric problem for a long thick-walled cylinder containing a ring-shaped internal or edge crack is considered. Using the standard transform technique the problem is formulated in terms of an integral equation which has a simple Cauchy kernel for the internal crack and a generalized Cauchy kernel for the edge crack as the dominant part. As examples the uniform axial load and the steady-state thermal stress problems have been solved and the related stress intensity factors have been calculated. Among other findings the results show that in the cylinder under uniform axial stress containing an internal crack the stress intensity factor at the inner tip is always greater than that at the outer tip for equal net ligament thicknesses and in the cylinder with an edge crack which is under a state of thermal stress the stress intensity factor is a decreasing function of the crack depth, tending to zero as the crack depth approaches the wall thickness.

  12. Measurement of thickness of film deposited on the plasma-facing wall in the QUEST tokamak by colorimetry

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Hanada, K.; Yoshida, N.; Shimoji, T.; Miyamoto, M.; Oya, Y.; Zushi, H.; Idei, H.; Nakamura, K.; Fujisawa, A.; Nagashima, Y.; Hasegawa, M.; Kawasaki, S.; Higashijima, A.; Nakashima, H.; Nagata, T.; Kawaguchi, A.; Fujiwara, T.; Araki, K.; Mitarai, O.; Fukuyama, A.; Takase, Y.; Matsumoto, K.

    2017-09-01

    After several experimental campaigns in the Kyushu University Experiment with Steady-state Spherical Tokamak (QUEST), the originally stainless steel plasma-facing wall (PFW) becomes completely covered with a deposited film composed of mixture materials, such as iron, chromium, carbon, and tungsten. In this work, an innovative colorimetry-based method was developed to measure the thickness of the deposited film on the actual QUEST wall. Because the optical constants of the deposited film on the PFW were position-dependent and the extinction coefficient k1 was about 1.0-2.0, which made the probing light not penetrate through some thick deposited films, the colorimetry method developed can only provide a rough value range of thickness of the metal-containing film deposited on the actual PFW in QUEST. However, the use of colorimetry is of great benefit to large-area inspections and to radioactive materials in future fusion devices that will be strictly prohibited from being taken out of the limited area.

  13. Design and installation of a ferromagnetic wall in tokamak geometry.

    PubMed

    Hughes, P E; Levesque, J P; Rivera, N; Mauel, M E; Navratil, G A

    2015-10-01

    Low-activation ferritic steels are leading material candidates for use in next-generation fusion development experiments such as a prospective component test facility and DEMO power reactor. Understanding the interaction of plasmas with a ferromagnetic wall will provide crucial physics for these facilities. In order to study ferromagnetic effects in toroidal geometry, a ferritic wall upgrade was designed and installed in the High Beta Tokamak-Extended Pulse (HBT-EP). Several material options were investigated based on conductivity, magnetic permeability, vacuum compatibility, and other criteria, and the material of choice (high-cobalt steel) is characterized. Installation was accomplished quickly, with minimal impact on existing diagnostics and overall machine performance, and initial results demonstrate the effects of the ferritic wall on plasma stability.

  14. Design and installation of a ferromagnetic wall in tokamak geometry

    SciTech Connect

    Hughes, P. E. Levesque, J. P.; Rivera, N.; Mauel, M. E.; Navratil, G. A.

    2015-10-15

    Low-activation ferritic steels are leading material candidates for use in next-generation fusion development experiments such as a prospective component test facility and DEMO power reactor. Understanding the interaction of plasmas with a ferromagnetic wall will provide crucial physics for these facilities. In order to study ferromagnetic effects in toroidal geometry, a ferritic wall upgrade was designed and installed in the High Beta Tokamak–Extended Pulse (HBT-EP). Several material options were investigated based on conductivity, magnetic permeability, vacuum compatibility, and other criteria, and the material of choice (high-cobalt steel) is characterized. Installation was accomplished quickly, with minimal impact on existing diagnostics and overall machine performance, and initial results demonstrate the effects of the ferritic wall on plasma stability.

  15. Optimization of wall thickness and lay-up for the shell-like composite structure loaded by non-uniform pressure field

    NASA Astrophysics Data System (ADS)

    Shevtsov, S.; Zhilyaev, I.; Oganesyan, P.; Axenov, V.

    2017-01-01

    The glass/carbon fiber composites are widely used in the design of various aircraft and rotorcraft components such as fairings and cowlings, which have predominantly a shell-like geometry and are made of quasi-isotropic laminates. The main requirements to such the composite parts are the specified mechanical stiffness to withstand the non-uniform air pressure at the different flight conditions and reduce a level of noise caused by the airflow-induced vibrations at the constrained weight of the part. The main objective of present study is the optimization of wall thickness and lay-up of composite shell-like cowling. The present approach assumes conversion of the CAD model of the cowling surface to finite element (FE) representation, then its wind tunnel testing simulation at the different orientation of airflow to find the most stressed mode of flight. Numerical solutions of the Reynolds averaged Navier-Stokes (RANS) equations supplemented by k-w turbulence model provide the spatial distributions of air pressure applied to the shell surface. At the formulation of optimization problem the global strain energy calculated within the optimized shell was assumed as the objective. A wall thickness of the shell had to change over its surface to minimize the objective at the constrained weight. We used a parameterization of the problem that assumes an initiation of auxiliary sphere with varied radius and coordinates of the center, which were the design variables. Curve that formed by the intersection of the shell with sphere defined boundary of area, which should be reinforced by local thickening the shell wall. To eliminate a local stress concentration this increment was defined as the smooth function defined on the shell surface. As a result of structural optimization we obtained the thickness of shell's wall distribution, which then was used to design the draping and lay-up of composite prepreg layers. The global strain energy in the optimized cowling was reduced in2

  16. Estimation of emission cone wall thickness of Jupiter's decametric radio emission using stereoscopic STEREO/WAVES observations

    NASA Astrophysics Data System (ADS)

    Panchenko, M.; Rucker, H. O.

    2016-11-01

    Aims: Stereoscopic observations by the WAVES instrument onboard two STEREO spacecraft have been used with the aim of estimating wall thickness of an emission cone of Jovian decametric radio emission (DAM). Methods: Stereoscopic observations provided by STEREO-A and -B facilitate unambiguous recognition of the Jovian DAM in observed dynamic spectra as well as identification of its components (Io DAM or non-Io DAM). The dynamic spectra of radio emissions recorded by STEREO/WAVES have been analyzed using the method of cross-correlation of the radio dynamic spectra. Results: Altogether, 139 radio events, in particular 91 Io- and 48 non-Io-related radio events were observed. The averaged width of the emission cone wall for Io-DAM as well as for non-Io DAM is about 1.1° ± 0.2°. These results are in agreement with previous findings.

  17. Ureteral wall thickness at the impacted ureteral stone site: a critical predictor for success rates after SWL.

    PubMed

    Sarica, Kemal; Kafkasli, Alper; Yazici, Özgür; Çetinel, Ali Cihangir; Demirkol, Mehmet Kutlu; Tuncer, Murat; Şahin, Cahit; Eryildirim, Bilal

    2015-02-01

    The aim of the study was to determine the possible predictive value of certain patient- and stone-related factors on the stone-free rates and auxiliary procedures after extracorporeal shock wave lithotripsy in patients with impacted proximal ureteral calculi. A total of 111 patients (86 male, 25 females M/F: 3.44/1) with impacted proximal ureteral stones treated with shock wave lithotripsy were evaluated. Cases were retrieved from a departmental shock wave lithotripsy database. Variables analyzed included BMI of the case, diameter of proximal ureter and renal pelvis, stone size and Hounsfield unit, ureteral wall thickness at the impacted stone site. Stone-free status on follow-up imaging at 3 months was considered a successful outcome. All patients had a single impacted proximal ureteral stone. While the mean age of the cases was 46 ± 13 years (range 26-79 years), mean stone size was 8.95 mm (5.3-15.1 mm). Following shock wave lithotripsy although 87 patients (78.4%) were completely stone-free at 3-month follow-up visit, 24 (21.6%) cases had residual fragments requiring further repeat procedures. Prediction of the final outcome of SWL in patients with impacted proximal ureteral stones is a challenging issue and our data did clearly indicate a highly significant relationship between ureteral wall thickness and the success rates of shock wave lithotripsy particularly in cases requiring additional procedures. Of all the evaluated stone- and patient-related factors, only ureteral wall thickness at the impacted stone site independently predicted shock wave lithotripsy success.

  18. The thickness and the lengths of the anterior wall of adult maxilla of the West Anatolian Turkish people.

    PubMed

    Arman, Candan; Ergür, Ipek; Atabey, Atay; Güvencer, Mustafa; Kiray, Amac; Korman, Esin; Tetik, Suleyman

    2006-12-01

    The maxilla is the key structure on facial formation and stability. The knowledge about maxillary thickness and dimensions is crucial during facial reconstruction including this bone. In this study, anthropometric measurements of anterior wall of the maxilla on the dry human skulls were aimed. Sixty maxillae of 30 adult dry skulls of West Anatolian people were evaluated. Four vertical lines were drawn between the piriform aperture and lateral border of the bone and six horizontal lines between the infra-orbital margin and the inferior border of the piriform aperture. After establishing the lines, maxillary thicknesses on the intersection points of the vertical and horizontal lines and the lengths of the vertical lines from the infra-orbital margin to alveolar arch were measured by using a fine caliper. It was found that the thickest point of the anterior wall of the maxillae is on the lateral of the infra-orbital margin (5.17 +/- 2.27 mm), and thinnest one is on the inferior of the infra-orbital foramen (0.92 +/- 1.06 mm). The length of the vertical line tangent to piriform aperture (47.66 +/- 3.61 mm) is the longest. The corresponding data of the left and right maxillae were compared by Student's t test. There was no significant difference between both sides. After collecting the data, a thickness map of anterior wall of the maxilla was drawn. This data may be helpful in clinic during osteotomies, bone reconstructions, screw, or other reconstruction apparatus applications on the maxilla.

  19. Space- and time-resolved resistive measurements of liquid metal wall thickness.

    PubMed

    Mirhoseini, S M H; Volpe, F A

    2016-11-01

    In a fusion reactor internally coated with liquid metal, it will be important to diagnose the thickness of the liquid at various locations in the vessel, as a function of time, and possibly respond to counteract undesired bulging or depletion. The electrical conductance between electrodes immersed in the liquid metal can be used as a simple proxy for the local thickness. Here a matrix of electrodes is shown to provide spatially and temporally resolved measurements of liquid metal thickness in the absence of plasma. First a theory is developed for m × n electrodes, and then it is experimentally demonstrated for 3 × 1 electrodes, as the liquid stands still or is agitated by means of a shaker. The experiments were carried out with Galinstan, but are easily extended to lithium or other liquid metals.

  20. Space- and time-resolved resistive measurements of liquid metal wall thickness

    SciTech Connect

    Mirhoseini, S. M. H.; Volpe, F. A.

    2016-11-15

    In a fusion reactor internally coated with liquid metal, it will be important to diagnose the thickness of the liquid at various locations in the vessel, as a function of time, and possibly respond to counteract undesired bulging or depletion. The electrical conductance between electrodes immersed in the liquid metal can be used as a simple proxy for the local thickness. Here a matrix of electrodes is shown to provide spatially and temporally resolved measurements of liquid metal thickness in the absence of plasma. First a theory is developed for m × n electrodes, and then it is experimentally demonstrated for 3 × 1 electrodes, as the liquid stands still or is agitated by means of a shaker. The experiments were carried out with Galinstan, but are easily extended to lithium or other liquid metals.

  1. Space- and time-resolved resistive measurements of liquid metal wall thickness

    NASA Astrophysics Data System (ADS)

    Mirhoseini, S. M. H.; Volpe, F. A.

    2016-11-01

    In a fusion reactor internally coated with liquid metal, it will be important to diagnose the thickness of the liquid at various locations in the vessel, as a function of time, and possibly respond to counteract undesired bulging or depletion. The electrical conductance between electrodes immersed in the liquid metal can be used as a simple proxy for the local thickness. Here a matrix of electrodes is shown to provide spatially and temporally resolved measurements of liquid metal thickness in the absence of plasma. First a theory is developed for m × n electrodes, and then it is experimentally demonstrated for 3 × 1 electrodes, as the liquid stands still or is agitated by means of a shaker. The experiments were carried out with Galinstan, but are easily extended to lithium or other liquid metals.

  2. Free and Forced Vibrations of Thick-Walled Anisotropic Cylindrical Shells

    NASA Astrophysics Data System (ADS)

    Marchuk, A. V.; Gnedash, S. V.; Levkovskii, S. A.

    2017-03-01

    Two approaches to studying the free and forced axisymmetric vibrations of cylindrical shell are proposed. They are based on the three-dimensional theory of elasticity and division of the original cylindrical shell with concentric cross-sectional circles into several coaxial cylindrical shells. One approach uses linear polynomials to approximate functions defined in plan and across the thickness. The other approach also uses linear polynomials to approximate functions defined in plan, but their variation with thickness is described by the analytical solution of a system of differential equations. Both approaches have approximation and arithmetic errors. When determining the natural frequencies by the semi-analytical finite-element method in combination with the divide and conqure method, it is convenient to find the initial frequencies by the finite-element method. The behavior of the shell during free and forced vibrations is analyzed in the case where the loading area is half the shell thickness

  3. Analysis and optimal design of thick composite structures with passive damping considerations

    NASA Technical Reports Server (NTRS)

    Saravanos, D. A.

    1992-01-01

    A design methodology to tailor thick composite plates for optimal static and damping performance is presented. The method is based on discrete layer composite mechanics, hence, is suitable for thick composite laminates. The design criteria include static deflections, frequency and damping constraints. Evaluations on cross-ply simply-supported plates illustrate the advantages of the methodology. Comparisons with design methods based on the classical laminate theory show significant deviations in the resultant optimal designs at higher thicknesses.

  4. A temperature correlation for the radiation resistance of a thick-walled circular duct exhausting a hot gas

    NASA Technical Reports Server (NTRS)

    Mahan, J. R.; Cline, J. G.; Jones, J. D.

    1984-01-01

    It is often useful to know the radiation impedance of an unflanged but thick-walled circular duct exhausting a hot gas into relatively cold surroundings. The reactive component is shown to be insensitive to temperature, but the resistive component is shown to be temperature dependent. A temperature correlation is developed permitting prediction of the radiation resistance from a knowledge of the temperature difference between the ambient air and the gas flowing from the duct, and a physical basis for this correlation is presented.

  5. The importance of ultrasonographic measurement of peritoneal wall thickness in pediatric chronic peritoneal dialysis patients.

    PubMed

    Yavaşcan, Önder; Aksu, Nejat; Alparslan, Caner; Sarıtaş, Serdar; Elmas, Cengiz Han; Eraslan, Ali Nihat; Duman, Soner; Mir, Sevgi

    2015-04-01

    Loss of peritoneal function due to peritoneal fibrosing syndrome (PFS) is a major factor leading to treatment failure in chronic peritoneal dialysis (PD) patients. Although the precise biologic mechanisms responsible for these changes have not been defined, the general assumption is that alterations in peritoneal function are related to structural changes in the peritoneal membrane. Studies of the peritoneal membrane by non-invasive ultrasonography (US) in chronic PD patients are limited. The aim of the present study is to assess the relationship between functional parameters of peritoneum and peritoneal thickness measured by US in children treated by chronic PD. We recruited two groups of patients: 23 subjects (13 females, 10 males) on chronic PD (patient group) and 26 (7 females, 19 males) on predialysis out-patient follow-up (creatinine clearance: 20-60 mL/min/1.73 m(2)) (control group). Age, sex, weight, height, body mass index (BMI), chronic PD duration, episodes of peritonitis and the results of peritoneal equilibration test (PET) were recorded. Hemoglobin (Hb), blood pressure (BP), left ventricular mass index (LVMI) and renal osteodystrophy (ROD) parameters were also obtained. The thickness of the parietal peritoneum was measured by trans-abdominal US in all children. Statistical analyses were performed by using Student's t and Pearson's correlation tests. Mean peritoneal thickness in chronic PD patients (1028.26 ± 157.26 μm) was significantly higher than control patients (786.52 ± 132.33). Mean peritoneal thickness was significantly correlated with mean body height (R(2) = 0.93, p < 0.05), BMI (R(2) = 0.25, p < 0.05), chronic PD duration (R(2) = 0.64, p < 0.05), episodes of peritonitis (R(2) = 0.93, p < 0.05), D/Pcreatinine (R(2) = 0.76, p < 0.05) and D4/D0glucose (R(2) = 0.81, p < 0.05). No correlation was found between peritoneal thickness and Hb, BP, LVMI and ROD parameters. In conclusion

  6. Instrumented thick-walled tube method for measuring thermal pressure in fluids and isotropic stresses in thermosetting resins

    NASA Astrophysics Data System (ADS)

    Merzlyakov, Mikhail; Simon, Sindee L.; McKenna, Gregory B.

    2005-06-01

    We have developed a method for measuring the thermal pressure coefficient and cure-induced and thermally induced stresses based on an instrumented thick-walled tube vessel. The device has been demonstrated at pressures up to 330 MPa and temperatures to 300 °C. The method uses a sealed stainless steel thick-walled tube to impose three-dimensional isotropic constraints. The tube is instrumented with strain gauges in hoop and in axial directions and can be used in open or closed configurations. By making measurements of the isotropic stresses as a function of temperature, the method allows determination of the thermal pressure coefficient in both the glassy and rubbery (or liquid) states. The method also can be used to measure isotropic stress development in thermosetting resins during cure and subsequent thermal cycling. Experimental results are presented for sucrose benzoate, di-2-ethylhexylsebacate, and an epoxy resin. The current report shows that the method provides reliable estimates for the thermal pressure coefficient. The thermal pressure coefficient is determined with resolution on the order of 10kPa/K. Among advantages of the method is that the tubes are reusable, even when measurements are made for cure response of thermosetting resins.

  7. The relationship between the metabolic syndrome and arterial wall thickness: A mosaic still to be interpreted.

    PubMed

    Scuteri, Angelo; Franco, Oscar H; Majiid, AlGhatrif; Jolita, Badariene; Sergey, Boytsov; Cheng, Hao-Min; Chen, Chen-Huan; Choi, Seong-Woo; Francesco, Cucca; De Buyzere, Marc L; Alessandro, Delitala; Marcus, Dörr; Gunnar, Engstrom; Albert, Hofman; Seul-Ki, Jeong; Kweon, Sun-Seog; Michel, Langlois; Lee, Young-Hoon; Mattace Raso, Francesco; Olle, Melander; Morrell, Cristopher H; Park, Kyeong-Soo; Rietzschel, Ernst R; Kristina, Ryliskiene; Ryliskyte, Ligita; Ulf, Schminke; David, Schlessinger; Shin, Min-Ho; Irina, Strazhesko; Shih-Hsien, Sung; Olga, Tkacheva; Völzke, Henry; Lakatta, Edward G; Nilsson, Peter

    2016-12-01

    We aimed to identify clusters of metabolic syndrome (MetS) components, risky for extremely high intima-media thickness. We studied 41,513 volunteers (men and women) from eleven cohorts worldwide, participating in the MARE (Metabolic syndrome and Artery REsearch) Consortium. Specific clusters of MetS components - high triglycerides-high blood pressure-abdominal obesity (TBW), low HDL cholesterol-high blood pressure-abdominal obesity (HBW), high glucose-high blood pressure-abdominal obesity (GBW) - were accompanied by a 50-90% significantly greater likelihood of presenting extremely high intima-media thickness (via ultrasound of carotid artery, CCA IMT), after controlling for age, sex, smoking, non-HDL cholesterol, and presence of diabetes mellitus. This likelihood is comparable to the effect of being 7-8 years older or of being a cigarette smoker or of having non-HDL cholesterol 50 mg/dl higher. The consistent association of specific clusters of MetS components with extremely thick (older) large artery cross-culturally suggests that identification of those clusters in clinical practice will facilitate a personalized health care and a better - i.e. more healthy and cost-effective - prevention of major cardiovascular (CV) events. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Stress analysis for wall structure in mobile hot cell design

    SciTech Connect

    Bahrin, Muhammad Hannan Rahman, Anwar Abdul Hamzah, Mohd Arif Mamat, Mohd Rizal; Azman, Azraf; Hasan, Hasni

    2016-01-22

    Malaysian Nuclear Agency is developing a Mobile Hot Cell (MHC) in order to handle and manage Spent High Activity Radioactive Sources (SHARS) such as teletherapy heads and irradiators. At present, there are only two units of MHC in the world, in South Africa and China. Malaysian Mobile Hot cell is developed by Malaysian Nuclear Agency with the assistance of IAEA expert, based on the design of South Africa and China, but with improved features. Stress analysis has been performed on the design in order to fulfil the safety requirement in operation of MHC. This paper discusses the loading analysis effect from the sand to the MHC wall structure.

  9. SU-C-BRA-04: Use of Esophageal Wall Thickness in Evaluation of the Response to Chemoradiation Therapy for Esophageal Cancer

    SciTech Connect

    Wang, J; Kligerman, S; Lu, W; Kang, M

    2015-06-15

    Purpose: To quantitatively evaluate the esophageal cancer response to chemoradiation therapy (CRT) by measuring the esophageal wall thickness in CT. Method: Two datasets were used in this study. The first dataset is composed of CT scans of 15 esophageal cancer patients and 15 normal controls. The second dataset is composed of 20 esophageal cancer patients who underwent PET/CT scans before (Pre-CRT) and after CRT (Post-CRT). We first segmented the esophagus using a multi-atlas-based algorithm. The esophageal wall thickness was then computed, on each slice, as the equivalent circle radius of the segmented esophagus excluding the lumen. To evaluate the changes of wall thickness, we computed the standard deviation (SD), coefficient of variation (COV, SD/Mean), and flatness [(Max–Min)/Mean] of wall thickness along the entire esophagus. Results: For the first dataset, the mean wall thickness of cancer patients and normal controls were 6.35 mm and 6.03 mm, respectively. The mean SD, COV, and flatness of the wall thickness were 2.59, 0.21, and 1.27 for the cancer patients and 1.99, 0.16, and 1.13 for normal controls. Statistically significant differences (p < 0.05) were identified in SD and flatness. For the second dataset, the mean wall thickness of pre-CRT and post-CRT patients was 7.13 mm and 6.84 mm, respectively. The mean SD, COV, and flatness were 1.81, 0.26, and 1.06 for pre-CRT and 1.69, 0.26, and 1.06 for post-CRT. Statistically significant difference was not identified for these measurements. Current results are based on the entire esophagus. We believe significant differences between pre- and post-CRT scans could be obtained, if we conduct the measurements at tumor sites. Conclusion: Results show thicker wall thickness in pre-CRT scans and differences in wall thickness changes between normal and abnormal esophagus. This demonstrated the potential of esophageal wall thickness as a marker in the tumor CRT response evaluation. This work was supported in part by

  10. Design of Wall Segments for Ferritic Wall Mode Studies on HBT-EP

    NASA Astrophysics Data System (ADS)

    Hughes, Paul; Bialek, J.; Boozer, A.; Mauel, M. E.; Levesque, J. P.; Navratil, G. A.

    2012-10-01

    Low-activation ferritic steels are leading material candidates for use in next-generation fusion development experiments such as a prospective US component test facility and DEMO [1]. Understanding the interaction of plasmas with a ferromagnetic wall will be crucial physics for these experiments. Although there has been a linear FRWM experiment [2], the FRWM has not yet been observed in toroidal geometry. Using its high-resolution magnetic diagnostics, HBT-EP will explore the dynamics and stability of plasma interacting with ferromagnetic materials. We describe simple models [3] for plasma-wall interaction in the presence of ferromagnetic material, and compare material options for magnetic properties, cost, and ease of fabrication. Also, initial modeling, design, and installation of moderate permeability (1<μ<10) wall segments on HBT-EP will be discussed.[4pt] [1] Kurtz, R.J., et. al. 2009 J Nucl Mater 386-388[0pt] [2] Bergerson, W., et. al. 2008 Phys Rev Lett 101[0pt] [3] Kurita, G., et. al. 2003 Nucl Fus 43 949-954

  11. Space station integrated wall design and penetration damage control

    NASA Technical Reports Server (NTRS)

    Coronado, A. R.; Gibbins, M. N.; Wright, M. A.; Stern, P. H.

    1987-01-01

    A methodology was developed to allow a designer to optimize the pressure wall, insulation, and meteoroid/debris shield system of a manned spacecraft for a given spacecraft configuration and threat environment. The threat environment consists of meteoroids and orbital debris, as specified for an arbitrary orbit and expected lifetime. An overall probability of no penetration is calculated, as well as contours of equal threat that take into account spacecraft geometry and orientation. Techniques, tools, and procedures for repairing an impacted and penetrated pressure wall were developed and tested. These techniques are applied from the spacecraft interior and account for the possibility of performing the repair in a vacuum. Hypervelocity impact testing was conducted to: (1) develop and refine appropriate penetration functions, and (2) determine the internal effects of a penetration on personnel and equipment.

  12. Different Transition Mechanisms and Tunable Wall Thicknesses of Block Copolymer Vesicles

    NASA Astrophysics Data System (ADS)

    Xiao, Mengying; Wang, Rong; Xie, Daiqian

    2013-03-01

    By using dissipative particle dynamics, we studied how to control the two pathways for vesicle-formation mechanism considering the hydrophobic/hydrophilic block ratio, polymer-solvent interaction, and polymer concentration. A crucial balance between the segregation of inner-hydrophobic beads and the attraction of outer-hydrophilic beads drastically affects the self-assembly pathways of amphiphilic block copolymer into vesicles from one mechanism over the other. And during the transition period between these two pathways, vesicles are formed through an in-between pathway. In addition, we have evaluated the thickness of the hydrophobic layer and observed two types of dependence on the vesicle size. Our results indicate that as the degree of hydrophobicity of the blocks increases, from the whole strong behavior to the whole weak behavior relationship, the transformation is observed in large sized vesicles first and then in small sized vesicles. Two characteristics, the chain compaction of the vesicles and the area densities of inner corona, are thought to be important in controlling the membrane thickness. Acknowledgments.This work has been supported by NNSFC (Nos. 20874046, 21074053 and 21133006) and NBRPC (No. 2010CB923303).

  13. Thickness dependent sensing mechanism in sorted semi-conducting single walled nanotube based sensors.

    PubMed

    Battie, Yann; Gorintin, Louis; Ducloux, Olivier; Thobois, Philippe; Bondavalli, Paolo; Feugnet, Gilles; Loiseau, Annick

    2012-05-07

    Single walled carbon nanotube (SWCNT) networks present outstanding potential for the development of SWCNT-based gas sensors. Due to the complexity of the transport properties of this material, the physical mechanisms at stake during exposure to gas are still under debate. Previously suggested mechanisms are charge transfer between gas molecules and SWCNT and Schottky barrier modulation. By comparing electrical measurements with an analytical model based on Schottky barrier modulation, we demonstrate that one mechanism or the other is predominant depending on the percolation of metallic carbon nanotubes. Below the metallic SWCNT percolation threshold, sensing is dominated by the modulation of the Schottky barrier, while above this threshold, it is only attributed to a charge transfer between SWCNT and gas molecules. Both mechanisms are discussed in terms of sensitivity and resolution leading to routes for the optimization of a gas sensor architecture based on highly enriched semiconducting carbon nanotube films.

  14. DOUBLE-WALL COLLIMATOR DESIGN OF THE SNS PROJECT.

    SciTech Connect

    SIMOS,N.; LUDEWIG,H.; CATALAN-LASHERAS,N.; CRIVELLO,S.

    2001-06-18

    The collimator absorber array of the Spallation Neutron Source (SNS) project is responsible for stopping the 1.0 GeV protons that are in the halo of the beam. It is estimated that 0.1% of the 2 MW beam will be intercepted by the adopted collimating scheme implemented at various sections of the beam transport and accumulation. This paper summarizes the conceptual design of the collimator absorber as well as the supporting detailed analysis that were performed and guided the design process. Key requirement in the design process is the need for the collimator beam tube to minimize beam impedance while closely following its beta function. Due to lack of available experimental data, the long-term behavior of irradiated materials in an environment where they interface with coolant flow becomes an issue. Uncertainties in the long-term behavior prompted a special double-wall design that will enable not only beam halo interception but also the efficient transfer of deposited energy both under normal and off-normal conditions to the coolant flow. The thermo-mechanical response of the double wall beam tube and of a particle bed surrounding it are discussed in detail in the paper.

  15. The impact of transcatheter aortic valve implantation on left ventricular performance and wall thickness – single-centre experience

    PubMed Central

    Szymański, Piotr; Dąbrowski, Maciej; Zakrzewski, Dariusz; Michałek, Piotr; Orłowska-Baranowska, Ewa; El-Hassan, Kamal; Chmielak, Zbigniew; Witkowski, Adam; Hryniewiecki, Tomasz

    2015-01-01

    Introduction Transcatheter aortic valve implantation (TAVI) is a treatment alternative for the elderly population with severe symptomatic aortic stenosis (AS) at high risk for surgical aortic valve replacement (SAVR). Aim To assess the impact of TAVI on echocardiographic parameters of left ventricular (LV) performance and wall thickness in patients subjected to the procedure in a single-centre between 2009 and 2013. Material and methods The initial group consisted of 170 consecutive patients with severe AS unsuitable for SAVR. Logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 21.73 ±12.42% and mean age was 79.9 ±7.5 years. Results The TAVI was performed in 167 (98.2%) patients. Mean aortic gradient decreased significantly more rapidly after the procedure (from 58.6 ±16.7 mm Hg to 11.9 ±4.9 mm Hg, p < 0.001). The LV ejection fraction (LVEF) significantly increased in both short-term and long-term follow-up (57 ±14% vs. 59 ±13%, p < 0.001 and 56 ±14% vs. 60 ±12%, p < 0.001, respectively). Significant regression of interventricular septum diameter at end-diastole (IVSDD) and end-diastolic posterior wall thickness (EDPWth) was noted in early (15.0 ±2.4 mm vs. 14.5 ±2.3 mm, p < 0.001 and 12.7 ±2.1 mm vs. 12.4 ±1.9 mm, p < 0.028, respectively) and late post-TAVI period (15.1 ±2.5 mm to 14.3 ±2.5 mm, p < 0.001 and 12.8 ±2.0 mm to 12.4 ±1.9 mm, p < 0.007, respectively). Significant paravalvular leak (PL) was noted in 21 (13.1%) patients immediately after TAVI and in 13 (9.6%) patients in follow-up (p < 0.001). Moderate or severe mitral regurgitation (msMR) was seen in 24 (14.9%) patients from the initial group and in 19 (11.8%) patients after TAVI (p < 0.001). Conclusions The TAVI had an immediate beneficial effect on LVEF, LV walls thickness, and the incidence of msMR. The results of the procedure are comparable with those described in other centres. PMID:25848369

  16. Single-Walled Carbon Nanotube Film Supported Nanofiltration Membrane with a Nearly 10 nm Thick Polyamide Selective Layer for High-Flux and High-Rejection Desalination.

    PubMed

    Zhu, Yuzhang; Xie, Wei; Gao, Shoujian; Zhang, Feng; Zhang, Wenbin; Liu, Zhaoyang; Jin, Jian

    2016-09-01

    Fabricating nanofiltration (NF) membranes with high permeating flux and simultaneous high rejection rate for desalination is rather significant and highly desired. A new avenue is reported in this work to design NF membrane by using polydopamine wrapped single-walled carbon nanotube (PD/SWCNTs) ultrathin film as support layer instead of the use of traditional polymer-based underlying layers. Thanks to the high porosity, smooth surface, and more importantly optimal hydrophilic surface of PD/SWCNTs film, a defect-free polyamide selective layer for NF membrane with thickness of as thin as 12 nm is achieved. The obtained NF membrane exhibits an extremely high performance with a permeating flux of 32 L m(-2) h(-1) bar(-1) and a rejection rate of 95.9% to divalent ions. This value is two to five times higher than the traditional NF membranes with similar rejection rate.

  17. Quantitative evaluation of the relationship between dorsal wall length, sole thickness, and rotation of the distal phalanx in the bovine claw using computed tomography.

    PubMed

    Tsuka, T; Murahata, Y; Azuma, K; Osaki, T; Ito, N; Okamoto, Y; Imagawa, T

    2014-10-01

    Computed tomography (CT) was performed on 800 untrimmed claws (400 inner claws and 400 outer claws) of 200 pairs of bovine hindlimbs to investigate the relationships between dorsal wall length and sole thickness, and between dorsal wall length and the relative rotation angle of distal phalanx-to-sole surface (S-D angle). Sole thickness was 3.8 and 4.0 mm at the apex of the inner claws and outer claws, respectively, with dorsal wall lengths <70 mm. These sole thickness values were less than the critical limit of 5 mm, which is associated with a softer surface following thinning of the soles. A sole thickness of 5 mm at the apex was estimated to correlate with dorsal wall lengths of 72.1 and 72.7 mm for the inner and outer claws, respectively. Sole thickness was 6.1 and 6.4 mm at the apex of the inner and outer claws, respectively, with dorsal wall lengths of 75 mm. These sole thickness values were less than the recommended sole thickness of 7 mm based on the protective function of the soles. A sole thickness >7 mm at the apex was estimated to correlate with a dorsal wall length of 79.8 and 78.4mm for the inner and outer claws, respectively. The S-D angles were recorded as anteversions of 2.9° and 4.7° for the inner and outer claws, respectively, with a dorsal wall length of 75 mm. These values indicate that the distal phalanx is likely to have rotated naturally forward toward the sole surface. The distal phalanx rotated backward to the sole surface at 3.2° and 7.6° for inner claws with dorsal wall lengths of 90-99 and ≥100 mm, respectively; and at 3.5° for outer claws with a dorsal wall length ≥100 mm. Dorsal wall lengths of 85.7 and 97.2 mm were estimated to correlate with a parallel positional relationship of the distal phalanx to the sole surface in the inner and outer claws, respectively.

  18. Liquid Wall Chambers

    SciTech Connect

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  19. Environmentally-controlled fracture of an overstrained A723 steel thick-walled cylinder

    NASA Astrophysics Data System (ADS)

    Underwood, J. H.; Olmstead, V. J.; Askew, J. C.; Kapusta, A. A.; Young, G. A.

    1992-08-01

    A through-wall, 1.7 m long crack grew suddenly from a notch in a 285 mm outer diameter (OD) of an A723 steel overstrained tube that was undergoing plating operations with no externally applied loads. The fracture mechanics tests and analyses and the fractography performed to characterize the cracking are described. The tube had a yield strength of 1200 MPa, fracture toughness of 150 MPavm, and a tensile residual stress at the OD of about 600 MPa. The composition was typical of an air-melt A723 steel, and the electropolishing bath, consisting of sulfuric and phosphoric acids, was held at 54 C. The bolt-loaded test for the threshold stress intensity factor for environmentally controlled cracking described by Wei and Novak was used here with two significant modifications. Some tests included only a notch with the radius matching that of the tube, and a new expression for K in terms of crack-mouth displacement was developed and used. Scanning electron microscope fractography and energy dispersive x ray spectra were used to identify crack mechanisms. Results of the study include: (1) a measured threshold of hydrogen stress cracking for the material/environment below 20 MPavm; (2) da/dt versus K behavior typical of classic environmental control; and (3) an improved K/v expression for the bolt-loaded specimen and associated criteria for determining plane-strain test conditions in relation to the Irwin plastic zone.

  20. Uncertainty induced by chest wall thickness assessment methods on lung activity estimation for plutonium and americium: a large population-based study.

    PubMed

    Broggio, D; Lechaftois, X; Franck, D

    2015-03-01

    In vivo lung counting aims at assessing the retained activity in the lungs. The calibration factor relating the measured counts to the worker's specific retained lung activity can be obtained by several means and strongly depends on the chest wall thickness. Here we compare, for 374 male nuclear workers, the activity assessed with a reference protocol, where the material equivalent chest wall thickness is known from ultrasound measurements, with two other protocols. The counting system is an array of four germanium detectors.It is found that non site-specific equations for the assessment of the chest wall thickness induce large biases in the assessment of activity. For plutonium isotopes or (241)Am the proportion of workers for whom the retained activity is within ± 10% of the reference one is smaller than 10%.The use of site-specific equations raises this proportion to 20% and 58% for plutonium and (241)Am, respectively.Finally, for the studied population, when site-specific equations are used for the chest wall thickness, the standard uncertainties for the lung activity are 42% and 12.5%, for plutonium and (241)Am, respectively. Due to the relatively large size of the studied population, these values are a relatively robust estimate of the uncertainties due to the assessment of the chest wall thickness for the current practice at this site.

  1. Fracture behavior of shallow cracks in full-thickness clad beams from an RPV wall section

    SciTech Connect

    Keeney, J.A.; Bass, B.R.; McAfee, W.J.

    1995-04-01

    A testing program is described that utilizes full-thickness clad beam specimens to quantify fracture toughness for shallow cracks in weld material for which metallurgical conditions are prototypic of those found in reactor pressure vessels (RPVs). The beam specimens are fabricated from an RPV shell segment that includes weld, plate and clad material. Metallurgical factors potentially influencing fracture toughness for shallow cracks in the beam specimens include material gradients and material inhomogeneities in welded regions. The shallow-crack clad beam specimens showed a significant loss of constraint similar to that of other shallow-crack single-edge notch bend (SENB) specimens. The stress-based Dodds-Anderson scaling model appears to be effective in adjusting the test data to account for in-plane loss of constraint for uniaxially tested beams, but cannot predict the observed effects of out-of-plane biaxial loading on shallow-crack fracture toughness. A strain-based dual-parameter fracture toughness correlation (based on plastic zone width) performed acceptably when applied to the uniaxial and biaxial shallow-crack fracture toughness data.

  2. Estimation of PSD Shifts for High-Resolution Metrology of Thickness Micro-Changes with Possible Applications in Vessel Walls and Biological Membrane Characterization

    PubMed Central

    Ramos, Antonio; Bazán, Ivonne; Negreira, Carlos; Brum, Javier; Gómez, Tomás; Calás, Héctor; Ruiz, Abelardo; de la Rosa, José Manuel

    2012-01-01

    Achieving accurate measurements of inflammation levels in tissues or thickness changes in biological membranes (e.g., amniotic sac, parietal pleura) and thin biological walls (e.g., blood vessels) from outside the human body, is a promising research line in the medical area. It would provide a technical basis to study the options for early diagnosis of some serious diseases such as hypertension, atherosclerosis or tuberculosis. Nevertheless, achieving the aim of non-invasive measurement of those scarcely-accessible parameters on patient internal tissues, currently presents many difficulties. The use of high-frequency ultrasonic transducer systems appears to offer a possible solution. Previous studies using conventional ultrasonic imaging have shown this, but the spatial resolution was not sufficient so as to permit a thickness evaluation with clinical significance, which requires an accuracy of a few microns. In this paper a broadband ultrasonic technique, that was recently developed by the authors to address other non-invasive medical detection problems (by integrating a piezoelectric transducer into a spectral measuring system), is extended to our new objective; the aim is its application to the thickness measurement of sub-millimeter membranes or layers made of materials similar to some biological tissues (phantoms). The modeling and design rules of such a transducer system are described, and various methods of estimating overtones location in the power spectral density (PSD) are quantitatively assessed with transducer signals acquired using piezoelectric systems and also generated from a multi-echo model. Their effects on the potential resolution of the proposed thickness measuring tool, and their capability to provide accuracies around the micron are studied in detail. Comparisons are made with typical tools for extracting spatial parameters in laminar samples from echo-waveforms acquired with ultrasonic transducers. Results of this advanced measurement

  3. Left ventricular wall thickness in patients with hypertrophic cardiomyopathy: a comparison between cardiac magnetic resonance imaging and echocardiography.

    PubMed

    Corona-Villalobos, Celia P; Sorensen, Lars L; Pozios, Iraklis; Chu, Linda; Eng, John; Abraham, Maria Roselle; Abraham, Theodore P; Kamel, Ihab R; Zimmerman, Stefan L

    2016-06-01

    We assessed whether cardiac MRI (CMR) and echocardiography (echo) have significant differences measuring left ventricular (LV) wall thickness (WT) in hypertrophic cardiomyopathy (HCM) as performed in the clinical routine. Retrospectively identified, clinically diagnosed HCM patients with interventricular-septal (IVS) pattern hypertrophy who underwent CMR and echo within the same day were included. Left Ventricular WT was measured by CMR in two planes and compared to both echo and contrast echo (cecho). 72 subjects, mean age 50.7 ± 16.2 years, 68 % males. Interventricular septal WT by echo and CMR planes showed good to excellent correlation. However, measurements of the postero-lateral wall showed poor correlation. Bland-Altman plots showed greater maximal IVS WT by echo compared to CMR measurement [SAX = 1.7 mm (-5.8, 9.3); LVOT = 1.1 mm (-5.6, 7.8)]. Differences were smaller between cecho and CMR [SAX = 0.8 mm (-9.2, 10.8); LVOT = -0.2 mm (-10.0, 9.6)]. Severity of WT by quartiles showed greater differences between echo and SAX CMR WT compared to cecho. Echocardiography typically measures greater WT than CMR, with the largest differences in moderate to severe hypertrophy. Contrast echocardiography more closely approximates CMR measurements of WT. These findings have potential clinical implications for risk stratification of subjects with HCM.

  4. Wall irregularity rather than intima-media thickness is associated with nearby atherosclerosis.

    PubMed

    Graf, Iulia M; Schreuder, Floris H B M; Hameleers, Jeroen M; Mess, Werner H; Reneman, Robert S; Hoeks, Arnold P G

    2009-06-01

    In addition to intima-media thickness (IMT), IMT inhomogeneity may carry information about atherosclerosis progression. In 147 vascular diseased patients (mean 66 y, 48% male), we determined the carotid bulb stenosis degree based on local Doppler blood flow velocities. Common carotid artery (CCA) morphologic characteristics, i.e. IMT, IMT-inhomogeneity (intraregistration variation) and IMT uni- and bilateral intrasubject variation (DeltaIMT), were measured using multiple M-mode. Associations of morphologic characteristics, stenosis degree and Framingham score were evaluated with Pearson correlation (r) and multiple regression analysis. The IMT distributions for subjects without and with stenosis were not similar. The stenosis degree score correlated significantly to unilateral (r=0.68) and bilateral DeltaIMT (r=0.62), IMT (r=0.41) and IMT-inhomogeneity (r=0.45). The averaged IMT and IMT-inhomogeneity increased slightly for singular stenosis and abruptly for multiple stenoses. Mean uni- and bilateral DeltaIMT per stenosis degree increased linearly with this degree, reaching a correlation close to 1 (r=0.98 and r=0.97). Interestingly, the majority of the subjects with a moderate to severe bulb stenosis exhibited a carotid IMT lower than the considered critical threshold of 0.9 mm. In conclusion, although CCA is not prone to plaques, its morphologic characteristics are positively correlated with stenosis degree score and other risk scores. DeltaIMT can be more reliable derived from inter-registration rather than from intra-registration variation. In the CCA, DeltaIMT substantiates vascular alteration better than IMT.

  5. Left ventricular hypertrophy, aortic wall thickness, and lifetime predicted risk of cardiovascular disease:the Dallas Heart Study.

    PubMed

    Gupta, Sachin; Berry, Jarett D; Ayers, Colby R; Peshock, Ronald M; Khera, Amit; de Lemos, James A; Patel, Parag C; Markham, David W; Drazner, Mark H

    2010-06-01

    To examine whether individuals with low short-term risk of coronary heart disease but high lifetime predicted risk of cardiovascular disease (CVD) have greater prevalence of left ventricular (LV) hypertrophy and increased aortic wall thickness (AWT) than those with low short-term and low lifetime risk. Lifetime risk prediction can be used for stratifying individuals younger than 50 years of age into 2 groups: low short-term/high lifetime and low short-term/low lifetime predicted risk of CVD. Individuals with low short-term/high lifetime risk have a greater burden of subclinical atherosclerosis as measured by coronary artery calcium and carotid intima-media thickness. However, >75% of individuals with low short-term/high lifetime risk do not have detectable coronary artery calcium, suggesting the presence of alternative subclinical abnormalities. We stratified 1,804 Dallas Heart Study subjects between the ages of 30 and 50 years who had cardiac magnetic resonance into 3 groups: low short-term (<10% 10-year risk of coronary heart disease)/low lifetime predicted risk (<39% lifetime risk of CVD), low short-term (<10%)/high lifetime risk (> or =39%), and high short-term risk (> or =10%, prevalent diabetes, or previous stroke, or myocardial infarction). In those with low short-term risk, we compared measures of LV hypertrophy and AWT between those with low versus high lifetime risk. Subjects with low short-term/high lifetime risk compared with those with low short-term/low lifetime risk had increased LV mass (men: 95 +/- 17 g/m(2) vs. 90 +/- 12 g/m(2) and women: 75 +/- 14 g/m(2) vs. 71 +/- 10 g/m(2), respectively; p < 0.001 for both). LV concentricity (mass/volume), wall thickness, and AWT were also significantly greater in those with high lifetime risk in this comparison (p < 0.001 for all), but LV end-diastolic volume was not (p > 0.3). These associations persisted among participants without detectable coronary artery calcium. Among individuals 30 to 50 years of age

  6. Towards a strategy of reliable fusion first-wall design

    SciTech Connect

    Schultz, J. H.

    1981-05-01

    Fusion first walls are subject to a large number of possible failure mechanisms, including erosion due to sputtering, arcing, blistering and vaporization and crack growth due to thermal and magnetic stresses. Each of these failure mechanisms is poorly characterized and has the potential of being severe. A strategy for designing reliably in the face of great uncertainty is discussed. Topological features beneficial to reactor availability are identified. The integration of limiter pumping with rf wave launching is discussed, as a means of simplifying reactor design. The concept of a sewer limiter is introduced, as a possible long-life limiter topology. The concept of flexible armor is discussed, as a means of extending maximum life.

  7. Finite element analysis of the Arquin-designed CMU wall under a dynamic (blast) load.

    SciTech Connect

    Lopez, Carlos; Petti, Jason P.

    2008-12-01

    The Arquin Corporation designed a CMU (concrete masonry unit) wall construction and reinforcement technique that includes steel wire and polymer spacers that is intended to facilitate a faster and stronger wall construction. Since the construction method for an Arquin-designed wall is different from current wall construction practices, finite element computer analyses were performed to estimate the ability of the wall to withstand a hypothetical dynamic load, similar to that of a blast from a nearby explosion. The response of the Arquin wall was compared to the response of an idealized standard masonry wall exposed to the same dynamic load. Results from the simulations show that the Arquin wall deformed less than the idealized standard wall under such loading conditions. As part of a different effort, Sandia National Laboratories also looked at the relative static response of the Arquin wall, results that are summarized in a separate SAND Report.

  8. Axial heat transport in He II in a thick-walled copper channel

    SciTech Connect

    Canavan, E.; Van Sciver, S.W.

    1982-01-01

    A computer model was developed to simulate a configuration similar to a short section of He II cooling channel in a copper-stabilized magnet. The model produces steady copper and helium temperature distributions that agree in form with experimental measurements of the configuration. However, for more exact simulation it is necessary to measure independently the Kapitza conductance and thermal conductivity. Such a model, if extended somewhat and included in a larger system, could prove a valuable tool in the design of He II stabilized magnet. Subsequent discussion concerned the model with the Kapitza coefficient h /SUB o/ = 0.

  9. Reliability Coupled Sensitivity Based Design Approach for Gravity Retaining Walls

    NASA Astrophysics Data System (ADS)

    Guha Ray, A.; Baidya, D. K.

    2012-09-01

    Sensitivity analysis involving different random variables and different potential failure modes of a gravity retaining wall focuses on the fact that high sensitivity of a particular variable on a particular mode of failure does not necessarily imply a remarkable contribution to the overall failure probability. The present paper aims at identifying a probabilistic risk factor ( R f ) for each random variable based on the combined effects of failure probability ( P f ) of each mode of failure of a gravity retaining wall and sensitivity of each of the random variables on these failure modes. P f is calculated by Monte Carlo simulation and sensitivity analysis of each random variable is carried out by F-test analysis. The structure, redesigned by modifying the original random variables with the risk factors, is safe against all the variations of random variables. It is observed that R f for friction angle of backfill soil ( φ 1 ) increases and cohesion of foundation soil ( c 2 ) decreases with an increase of variation of φ 1 , while R f for unit weights ( γ 1 and γ 2 ) for both soil and friction angle of foundation soil ( φ 2 ) remains almost constant for variation of soil properties. The results compared well with some of the existing deterministic and probabilistic methods and found to be cost-effective. It is seen that if variation of φ 1 remains within 5 %, significant reduction in cross-sectional area can be achieved. But if the variation is more than 7-8 %, the structure needs to be modified. Finally design guidelines for different wall dimensions, based on the present approach, are proposed.

  10. Effects of finite wall thickness and sinusoidal heating on convection in nanofluid-saturated local thermal non-equilibrium porous cavity

    NASA Astrophysics Data System (ADS)

    Alsabery, A. I.; Chamkha, A. J.; Saleh, H.; Hashim, I.; Chanane, B.

    2017-03-01

    The effects of finite wall thickness and sinusoidal heating on convection in a nanofluid-saturated local thermal non-equilibrium (LTNE) porous cavity are studied numerically using the finite difference method. The finite thickness vertical wall of the cavity is maintained at a constant temperature and the right wall is heated sinusoidally. The horizontal insulated walls allow no heat transfer to the surrounding. The Darcy law is used along with the Boussinesq approximation for the flow. Water-based nanofluids with Cu nanoparticles are chosen for investigation. The results of this study are obtained for various parameters such as the Rayleigh number, periodicity parameter, nanoparticles volume fraction, thermal conductivity ratio, ratio of wall thickness to its height and the modified conductivity ratio. Explanation for the influence of the various above-mentioned parameters on the streamlines, isotherms, local Nusselt number and the weighted average heat transfer is provided with regards to the thermal conductivities of nanoparticles suspended in the pure fluid and the porous medium. It is shown that the overall heat transfer is significantly increased with the relative non-uniform heating. Further, the convection heat transfer is shown to be inhibited by the presence of the solid wall. The results have possible applications in the heat-storage fluid-saturated porous systems and the applications of the high power heat transfer.

  11. Design and life assessment of first wall components

    SciTech Connect

    Diegele, E.; Munz, D.; Rizzi, G.

    1994-12-31

    The first wall (FW) of a tokamak fusion reactor is subjected to periodically changing high heat fluxes. The severe loading conditions imply restrictions on FW concepts. The selection of candidate structural materials, cooling media, range of operating temperatures design implementations in geometry terms as well as the questions of protection tiles and/or limiters are strongly interrelated. Any of these items could not be changed individually. Two very different approaches will be investigated: (1) High temperature concept. The FW is directly integrated as part of the blanket box, fabricated from vanadium alloys, cooled by liquid metal at 300{degrees}C-400{degrees}C from the rear part only, coated with a beryllium layer on the plasma side, and provided with beryllium limiters. This concept is being discussed in the current ITER engineering design phase. (2) Low temperature concept (reference design during ITER-CDA). Austenitic steel, SS 316 L, is used as structural material for the component, which is actively cooled (cooling tubes in FW) by water at low pressure and low temperatures of 60{degrees}C-100{degrees}C, and, on the plasma facing surface, is completely covered by protecting graphite (CFC) tiles. Both designs are critically evaluated with respect to their capability to accommodate admissible heat fluxes. Detailed temperature and stress analyses were performed for both. Stress levels and resistance to fatigue are being assessed.

  12. Design of Aerosol Particle Coating: Thickness, Texture and Efficiency

    PubMed Central

    Buesser, B.; Pratsinis, S.E.

    2013-01-01

    Core-shell particles preserve the performance (e.g. magnetic, plasmonic or opacifying) of a core material while modifying its surface with a shell that facilitates (e.g. by blocking its reactivity) their incorporation into a host liquid or polymer matrix. Here coating of titania (core) aerosol particles with thin silica shells (films or layers) is investigated at non-isothermal conditions by a trimodal aerosol dynamics model, accounting for SiO2 generation by gas phase and surface oxidation of hexamethyldisiloxane (HMDSO) vapor, coagulation and sintering. After TiO2 particles have reached their final primary particle size (e.g. upon completion of sintering during their flame synthesis), coating starts by uniformly mixing them with HMDSO vapor that is oxidized either in the gas phase or on the particles’ surface resulting in SiO2 aerosols or deposits, respectively. Sintering of SiO2 deposited onto the core TiO2 particles takes place transforming rough into smooth coating shells depending on process conditions. The core-shell characteristics (thickness, texture and efficiency) are calculated for two limiting cases of coating shells: perfectly smooth (e.g. hermetic) and fractal-like. At constant TiO2 core particle production rate, the influence of coating weight fraction, surface oxidation and core particle size on coating shell characteristics is investigated and compared to pertinent experimental data through coating diagrams. With an optimal temperature profile for complete precursor conversion, the TiO2 aerosol and SiO2-precursor (HMDSO) vapor concentrations have the strongest influence on product coating shell characteristics. PMID:23729833

  13. Numerical study of the coupling of two identification methods - thermal and electromagnetic - for the reconstruction of inclusions in thick walls

    NASA Astrophysics Data System (ADS)

    Le Touz, Nicolas; Dumoulin, Jean; Soldovieri, Francesco

    2016-04-01

    In this numerical study we present an approach allowing introducing a priori information in an identification method of internal thermal properties field for a thick wall using infrared thermography measurements. This method is based on a coupling with an electromagnetic reconstructing method which data are obtained from measurements of Ground Penetrating Radar (GPR) ([1], [2]). This new method aims at improving the accuracy of reconstructions performed by using only the thermal reconstruction method under quasi-periodic natural solicitation ([3], [4]). Indeed, these thermal reconstructions, without a priori information, have the disadvantage of being performed on the entire studied wall. Through the intake of information from GPR, it becomes possible to focus on the internal zones that may contain defects. These areas are obtained by defining subdomains around remarkable points identified with the GPR reconstruction and considered as belonging to a discontinuity. For thermal reconstruction without providing a priori information, we need to minimize a functional equal to a quadratic residue issued from the difference between the measurements and the results of the direct model. By defining search fields around these potential defects, and thus by forcing the thermal parameters further thereof, we provide information to the data to reconstruct. The minimization of the functional is then modified through the contribution of these constraints. We do not seek only to minimize a residue, but to minimize the overall residue and constraints, what changes the direction followed by the optimization algorithm in the space of thermal parameters to reconstruct. Providing a priori information may then allow to obtain reconstruction with higher residues but whose thermal parameters are better estimated, whether for locating potential defects or for the reconstructed values of these parameters. In particular, it is the case for air defects or more generally for defects having a

  14. Analysis of the effect of osteon diameter on the potential relationship of osteocyte lacuna density and osteon wall thickness.

    PubMed

    Skedros, John G; Clark, Gunnar C; Sorenson, Scott M; Taylor, Kevin W; Qiu, Shijing

    2011-09-01

    An important hypothesis is that the degree of infilling of secondary osteons (Haversian systems) is controlled by the inhibitory effect of osteocytes on osteoblasts, which might be mediated by sclerostin (a glycoprotein produced by osteocytes). Consequently, this inhibition could be proportional to cell number: relatively greater repression is exerted by progressively greater osteocyte density (increased osteocytes correlate with thinner osteon walls). This hypothesis has been examined, but only weakly supported, in sheep ulnae. We looked for this inverse relationship between osteon wall thickness (On.W.Th) and osteocyte lacuna density (Ot.Lc.N/B.Ar) in small and large osteons in human ribs, calcanei of sheep, deer, elk, and horses, and radii and third metacarpals of horses. Analyses involved: (1) all osteons, (2) smaller osteons, either ≤150 μm diameter or less than or equal to the mean diameter, and (3) larger osteons (>mean diameter). Significant, but weak, correlations between Ot.Lc.N/B.Ar and On.W.Th/On.Dm (On.Dm = osteon diameter) were found when considering all osteons in limb bones (r values -0.16 to -0.40, P < 0.01; resembling previous results in sheep ulnae: r = -0.39, P < 0.0001). In larger osteons, these relationships were either not significant (five/seven bone types) or very weak (two/seven bone types). In ribs, a negative relationship was only found in smaller osteons (r = -0.228, P < 0.01); this inverse relationship in smaller osteons did not occur in elk calcanei. These results do not provide clear or consistent support for the hypothesized inverse relationship. However, correlation analyses may fail to detect osteocyte-based repression of infilling if the signal is spatially nonuniform (e.g., increased near the central canal).

  15. Analysis of the Effect of Osteon Diameter on the Potential Relationship of Osteocyte Lacuna Density and Osteon Wall Thickness

    PubMed Central

    Skedros, John G.; Clark, Gunnar C.; Sorenson, Scott M.; Taylor, Kevin W.; Qiu, Shijing

    2011-01-01

    An important hypothesis is that the degree of infilling of secondary osteons (Haversian systems) is controlled by the inhibitory effect of osteocytes on osteoblasts, which might be mediated by sclerostin (a glycoprotein produced by osteocytes). Consequently, this inhibition could be proportional to cell number: relatively greater repression is exerted by progressively greater osteocyte density (increased osteocytes correlate with thinner osteon walls). This hypothesis has been examined, but only weakly supported, in sheep ulnae. We looked for this inverse relationship between osteon wall thickness (On.W.Th) and osteocyte lacuna density (Ot.Lc.N/B.Ar) in small and large osteons in human ribs, calcanei of sheep, deer, elk, and horses, and radii and third metacarpals of horses. Analyses involved: (1) all osteons, (2) smaller osteons, either ≤150μm diameter or ≤ the mean diameter, and (3) larger osteons (>mean diameter). Significant, but weak, correlations between Ot.Lc.N/B.Ar and On.W.Th/On.Dm (On.Dm = osteon diameter) were found when considering all osteons in limb bones (r values −0.16 to −0.40, p<0.01; resembling previous results in sheep ulnae: r= −0.39, p<0.0001). In larger osteons, these relationships were either not significant (five/seven bone types) or very weak (two/seven bone types). In ribs, a negative relationship was only found in smaller osteons (r= −0.228, p<0.01); this inverse relationship in smaller osteons did not occur in elk calcanei. These results do not provide clear or consistent support for the hypothesized inverse relationship. However, correlation analyses may fail to detect osteocyte-based repression of infilling if the signal is spatially non-uniform (e.g., increased near the central canal). PMID:21809466

  16. Sustainable green inner-wall design for flexible floor plan

    NASA Astrophysics Data System (ADS)

    Tawil, N. M.; Husaini, H. A.; Ani, A. I.; Basri, H.; Saleh, R. M.

    2013-06-01

    The rises of house price in the market is so drastic that it effects the younger generation nowadays especially young executives and young couples who could not afford to buy their first home. The factors that determine the house price presumably are the interior and exterior structural of the house itself. So to lessen the house price, we have to minimize the usage of wet construction thus the idea of having a sustainable green inner-wall implemented into the house with a flexible floor plan. This concept is user-friendly as it is built on needs and the ownership's affordability. They can design the interior of the house however they want with using minimal cost because it does not involve wet construction.

  17. Effects of Ceramic Fibre Insulation Thickness on Skin Formation and Nodule Characteristics of Thin Wall Ductile Iron Casting

    NASA Astrophysics Data System (ADS)

    Dhaneswara, D.; Suharno, B.; Nugraha, N. D.; Ariobimo, R. D. S.; Sofyan, N.

    2017-02-01

    Skin formation has become one of the problems in the thin wall ductile iron casting because it will reduce the mechanical properties of the materials. One of the solutions to reduce this skin formation is by using heat insulator to control the cooling rate. One of the insulators used for this purpose is ceramic fibre. In this research, the thickness of the ceramic fibre heat insulator used in the mould was varied, i.e. 50 mm on one side and 37.5 mm on the other side (A), no heat insulator (B), and 37.5 mm on both sides (C). After the casting process, the results were characterized in terms of metallography by using scanning electron microscope (SEM) and tensile test for mechanical properties. The results showed that the skin thickness formed in A is 34.21 μm, 23.38 μm in B, and 27.78 μm in C. The nodule count in A is 541.98 nodule/mm2 (84.7%) with an average diameter of 15.14 μm, 590 nodule/mm2 (86.7%) with an average diameter of 13.18 μm in B, and 549.73 nodule/mm2 (87.2%) with an average diameter of 13.95 μm in C. The average ultimate tensile strength for A was 399 MPa, B was 314 MPa, and C was 415 MPa. Microstructural examination under SEM showed that the materials have a ductile fracture with matrix full of ferrite.

  18. Design and Performance Evaluation of Slotted Walls for Two-Dimensional Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Barnwell, R. W.

    1978-01-01

    A procedure for designing slotted walls for two dimensional wind tunnels is is presented. The design objective is the minimization of blockage of streamline curvature or the reduction of both. The slotted wall boundary condition is derived both for flow from the tunnel into the plenum and vice versa, and the procedure for evaluating wall interference is described. A correlation of experimental data for the slotted wall boundary condition is given. Results are given for several designs and evaluations of slotted wind tunnel walls.

  19. Human coronary plaque wall thickness correlated positively with flow shear stress and negatively with plaque wall stress: an IVUS-based fluid-structure interaction multi-patient study.

    PubMed

    Fan, Rui; Tang, Dalin; Yang, Chun; Zheng, Jie; Bach, Richard; Wang, Liang; Muccigrosso, David; Billiar, Kristen; Zhu, Jian; Ma, Genshan; Maehara, Akiko; Mintz, Gary S

    2014-03-26

    Atherosclerotic plaque progression and rupture are believed to be associated with mechanical stress conditions. In this paper, patient-specific in vivo intravascular ultrasound (IVUS) coronary plaque image data were used to construct computational models with fluid-structure interaction (FSI) and cyclic bending to investigate correlations between plaque wall thickness and both flow shear stress and plaque wall stress conditions. IVUS data were acquired from 10 patients after voluntary informed consent. The X-ray angiogram was obtained prior to the pullback of the IVUS catheter to determine the location of the coronary artery stenosis, vessel curvature and cardiac motion. Cyclic bending was specified in the model representing the effect by heart contraction. 3D anisotropic FSI models were constructed and solved to obtain flow shear stress (FSS) and plaque wall stress (PWS) values. FSS and PWS values were obtained for statistical analysis. Correlations with p < 0.05 were deemed significant. Nine out of the 10 patients showed positive correlation between wall thickness and flow shear stress. The mean Pearson correlation r-value was 0.278 ± 0.181. Similarly, 9 out of the 10 patients showed negative correlation between wall thickness and plaque wall stress. The mean Pearson correlation r-value was -0.530 ± 0.210. Our results showed that plaque vessel wall thickness correlated positively with FSS and negatively with PWS. The patient-specific IVUS-based modeling approach has the potential to be used to investigate and identify possible mechanisms governing plaque progression and rupture and assist in diagnosis and intervention procedures. This represents a new direction of research. Further investigations using more patient follow-up data are warranted.

  20. On the thermal convection in a viscoelastic Jeffreys fluid layer heated from below confined between walls of finite thickness and thermal conductivity

    NASA Astrophysics Data System (ADS)

    Pérez-Reyes, Ildebrando; Vargas-Aguilar, René O.

    2016-11-01

    The thickness and thermal conductivity of the bounding walls are of interest in the hydrodynamic stability of a viscoelastic fluid layer. In this work the linear hydrodynamic stability is studied by means of the Galerkin method. The two ideal cases of thermal insulating and perfect thermal conducting walls are bridged by taking into account these two properties. Curves of criticality for the Rayleigh number, the wavenumber and the frequency of oscillation against the thermal conductivity for fixed wall thickness, Prandtl number and relaxation and retardation times are presented. Here, the dimensionless retardation time E was set to 0.05 and 0.1 while the dimensionless relaxation time F was set to 0.1 and 100. The role of the thermal conductivity and of the thickness of the walls are discussed. One important result of this investigation is that for non ideal thermal conducting conditions the system is more stable when the thickness of the fluid layer is larger in comparison to that of the boundaries. A discussion on the effect of E and F on the stability is given as well. Ciencia Básica - Conacyt through Project No. 255839.

  1. Dynamic reconstruction of full-thickness abdominal wall defects using free innervated vastus lateralis muscle flap combined with free anterolateral thigh flap.

    PubMed

    Iida, Takuya; Mihara, Makoto; Narushima, Mitsunaga; Todokoro, Takeshi; Hara, Hisako; Yoshimatu, Hidehiko; Koshima, Isao; Kadono, Takafumi

    2013-03-01

    Reconstruction of full-thickness abdominal wall defects remains a difficult surgical challenge. Although various reconstructive methods, including artificial mesh, pedicled and free flaps, have been reported, most reported reconstruction of only the fascia layer, leaving the resected rectus abdominis muscle unreconstructed. However, recent studies suggested the importance of dynamic reconstruction with functional muscle in preventing abdominal hernia in the long-term. According to the principle of reconstructive surgery, "replace lost tissue with similar tissue," a functionally and aesthetically ideal reconstruction is to reconstruct all components of the abdominal wall structure, including skin, subcutaneous fat, fascia, and muscle. We present 2 cases with full-thickness abdominal wall defects in the upper abdominal region, which we reconstructed with a free innervated vastus lateralis muscle flap combined with a free anterolateral thigh flap. The motor nerve of the vastus lateralis muscle was sutured with the intercostal nerve, and reinnervation was confirmed by electromyography. This method allows reconstruction of all components of the abdominal wall with a single flap, and dynamic reconstruction is achieved which will reduce the risk of postoperative hernia. We believe this method can be a good option for reconstruction of full-thickness abdominal wall defects with long-term stability.

  2. A tale of two neglected systems-structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves.

    PubMed

    Botha, C E J

    2013-01-01

    There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5-7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.

  3. A tale of two neglected systems—structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves

    PubMed Central

    Botha, C. E. J.

    2013-01-01

    There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer. PMID:23964280

  4. Welding for testability: An approach aimed at improving the ultrasonic testing of thick-walled austenitic and dissimilar metal welds

    SciTech Connect

    Wagner, Sabine; Dugan, Sandra; Barth, Martin; Schubert, Frank; Köhler, Bernd

    2014-02-18

    Austenitic and dissimilar welds in thick walled components show a coarse grained, dendritic microstructure. Therefore, ultrasonic testing has to deal with beam refraction, scattering and mode conversion effects. As a result, the testing techniques typically applied for isotropic materials yield dissatisfying results. Most approaches for improvement of ultrasonic testing have been based on modeling and improved knowledge of the complex wave propagation phenomena. In this paper, we discuss an alternative approach: is it possible to use a modified welding technology which eliminates the cause of the UT complications, i.e. the large-grained structure of the weld seams? Various modification parameters were tested, including: TIG current pulsing, additional DC and AC magnetic fields, and also additional external vibrations during welding. For all welds produced under different conditions, the grain structure of the weld seam was characterized by optical and GIUM microstructure visualizations on cross sections, wave field propagation measurements, and ultrasonic tests of correct detectability of flaws. The mechanical properties of the welds were also tested.

  5. A numerical study of multiple adiabatic shear bands evolution in a 304LSS thick-walled cylinder

    NASA Astrophysics Data System (ADS)

    Liu, Mingtao; Hu, Haibo; Fan, Cheng; Tang, Tiegang

    2017-01-01

    The self-organization of multiple shear bands in a 304L stainless steel(304LSS) thick-walled cylinder (TWC) was numerically studied. The microstructures of material lead to the non-uniform distribution of the local yield stress, which play a key role in the formation of spontaneous shear localization. We introduced a probability factor satisfied the Gaussian distribution into the macroscopic constitutive relationship to describe the non-uniformity of local yield stress. Using the probability factor, the initiation and propagation of multiple shear bands in TWC were numerically replicated in our 2D FEM simulation. Experimental results in the literature indicated that the machined surface at the internal boundary of a 304L stainless steel cylinder provides a work-hardened layer (about 20˜30μm) which has significantly different microstructures from the base material. The work-hardened layer leads to the phenomenon that most shear bands propagate along a given direction, clockwise or counterclockwise. In our simulation, periodical single direction spiral perturbations were applied to describe the grain orientation in the work-hardened layer, and the single direction spiral pattern of shear bands was successfully replicated.

  6. Effects of Exercise on Carotid Arterial Wall Thickness in Obese Pediatric Populations: A Meta-Analysis of Randomized Controlled Trials.

    PubMed

    García-Hermoso, Antonio; González-Ruiz, Katherine; Triana-Reina, Hector Reynaldo; Olloquequi, Jordi; Ramírez-Vélez, Robinson

    2017-04-01

    In pediatric populations, the use of carotid intima-media thickness (IMT) as a marker of cardiovascular risk has increased. However, previous studies examining the effects of exercise training on arterial structure and function in obese children and adolescents have shown inconsistent findings. The primary aim of this systematic review and meta-analysis is to expand on the current body of literature by providing a quantitative estimate of the change in carotid IMT following exercise training as well as to provide an exploratory analysis of potential moderators associated with the variation in response to an exercise training intervention in overweight and obese youth. A computerized search was made using three databases. The analysis was restricted to studies that examined the effect of exercise interventions on carotid IMT in pediatric obesity (6-18-year-olds). Hedges' g and 95% confidence intervals (CIs) were calculated. Six randomized controlled trials (303 youths) were included. Exercise was associated with a small-to-moderate but significant reduction in carotid IMT (g = -0.306; 95% CI -0.540 to -0.072; p = 0.011). Likewise, exercise program duration per week significantly influenced the effect of exercise on carotid IMT (β = -0.060; p = 0.015). Exercise seems to reduce carotid IMT in childhood obesity. Therefore, encouraging obese pediatric individuals to become physically active can lead to favorable changes in the arterial wall.

  7. Welding for testability: An approach aimed at improving the ultrasonic testing of thick-walled austenitic and dissimilar metal welds

    NASA Astrophysics Data System (ADS)

    Wagner, Sabine; Dugan, Sandra; Barth, Martin; Schubert, Frank; Köhler, Bernd

    2014-02-01

    Austenitic and dissimilar welds in thick walled components show a coarse grained, dendritic microstructure. Therefore, ultrasonic testing has to deal with beam refraction, scattering and mode conversion effects. As a result, the testing techniques typically applied for isotropic materials yield dissatisfying results. Most approaches for improvement of ultrasonic testing have been based on modeling and improved knowledge of the complex wave propagation phenomena. In this paper, we discuss an alternative approach: is it possible to use a modified welding technology which eliminates the cause of the UT complications, i.e. the large-grained structure of the weld seams? Various modification parameters were tested, including: TIG current pulsing, additional DC and AC magnetic fields, and also additional external vibrations during welding. For all welds produced under different conditions, the grain structure of the weld seam was characterized by optical and GIUM microstructure visualizations on cross sections, wave field propagation measurements, and ultrasonic tests of correct detectability of flaws. The mechanical properties of the welds were also tested.

  8. Dynamic load test of Arquin-designed CMU wall.

    SciTech Connect

    Jensen, Richard Pearson

    2010-02-01

    The Arquin Corporation has developed a new method of constructing CMU (concrete masonry unit) walls. This new method uses polymer spacers connected to steel wires that serve as reinforcing as well as a means of accurately placing the spacers so that the concrete block can be dry stacked. The hollows of the concrete block are then filled with grout. As part of a New Mexico Small Business Assistance Program (NMSBA), Sandia National Laboratories conducted a series of tests that dynamically loaded wall segments to compare the performance of walls constructed using the Arquin method to a more traditional method of constructing CMU walls. A total of four walls were built, two with traditional methods and two with the Arquin method. Two of the walls, one traditional and one Arquin, had every third cell filled with grout. The remaining two walls, one traditional and one Arquin, had every cell filled with grout. The walls were dynamically loaded with explosive forces. No significant difference was noted between the performance of the walls constructed by the Arquin method when compared to the walls constructed by the traditional method.

  9. Design of double-walled carbon nanotubes for biomedical applications

    NASA Astrophysics Data System (ADS)

    Neves, V.; Heister, E.; Costa, S.; Tîlmaciu, C.; Flahaut, E.; Soula, B.; Coley, H. M.; McFadden, J.; Silva, S. R. P.

    2012-09-01

    Double-walled carbon nanotubes (DWNTs) prepared by catalytic chemical vapour deposition were functionalized in such a way that they were optimally designed as a nano-vector for the delivery of small interfering RNA (siRNA), which is of great interest for biomedical research and drug development. DWNTs were initially oxidized and coated with a polypeptide (Poly(Lys:Phe)), which was then conjugated to thiol-modified siRNA using a heterobifunctional cross-linker. The obtained oxDWNT-siRNA was characterized by Raman spectroscopy inside and outside a biological environment (mammalian cells). Uptake of the custom-designed nanotubes was not associated with detectable biochemical perturbations in cultured cells, but transfection of cells with DWNTs loaded with siRNA targeting the green fluorescent protein (GFP) gene, serving as a model system, as well as with therapeutic siRNA targeting the survivin gene, led to a significant gene silencing effect, and in the latter case a resulting apoptotic effect in cancer cells.

  10. Research of the process of axisymmetric forming of thin-walled flat blanks into the conical parts with minimal thickness variation

    NASA Astrophysics Data System (ADS)

    Demyanenko, E. G.; Popov, I. P.; Menshikov, V. S.

    2017-02-01

    In this paper, the method based on the process of forming a flat blank into the thin-walled conical part is proposed. The forming method is based on two stages. At the first stage, forming of the free portion of the blank is carried out until it fully contacts the conical surface of the punch. During this stage, thickness unevenness is created, which can be compensated during the second stage by the action of active friction forces. The shaping of the workpiece during the forming of the conical part is performed by thinning. The thinning increases with the increase of the penetration depth of the punch, i.e. the final part will be thinner, but its thickness variation will be reduced. This method allows achieving minimal thickness variation in the walls of the part.

  11. Strategy Guideline: Modeling Enclosure Design in Above-Grade Walls

    SciTech Connect

    Lstiburek, J.; Ueno, K.; Musunuru, S.

    2016-02-24

    The Strategy Guideline describes how to model and interpret results of models for above grade walls. The Measure Guideline analyzes the failure thresholds and criteria for above grade walls. A library of above-grade walls with historically successful performance was used to calibrate WUFI (Warme Und Feuchte Instationar) software models. The information is generalized for application to a broad population of houses within the limits of existing experience.

  12. Method and apparatus to produce and maintain a thick, flowing, liquid lithium first wall for toroidal magnetic confinement DT fusion reactors

    DOEpatents

    Woolley, Robert D.

    2002-01-01

    A system for forming a thick flowing liquid metal, in this case lithium, layer on the inside wall of a toroid containing the plasma of a deuterium-tritium fusion reactor. The presence of the liquid metal layer or first wall serves to prevent neutron damage to the walls of the toroid. A poloidal current in the liquid metal layer is oriented so that it flows in the same direction as the current in a series of external magnets used to confine the plasma. This current alignment results in the liquid metal being forced against the wall of the toroid. After the liquid metal exits the toroid it is pumped to a heat extraction and power conversion device prior to being reentering the toroid.

  13. Method and Apparatus to Produce and Maintain a thick, flowing, Liquid Lithium first wall for Toroidal Magnetic Confinement DT Fusion Reactors

    SciTech Connect

    Woolley, Robert D.

    1998-10-21

    A system for forming a thick flowing liquid metal, in this case lithium, layer on the inside wall of a toroid containing the plasma of a deuterium-tritium fission reactor. The presence of the liquid metal layer or first wall serves to prevent neutron damage to the walls of the toroid. A poloidal current in the liquid metal layer is oriented so that it flows in the same direction as the current in a series of external magnets used to confine the plasma. This current alignment results in the liquid metal being forced against the wall of the toroid. After the liquid metal exits the toroid it is pumped to a heat extraction and power conversion device prior to being reentering the toroid.

  14. Influence of radiation dose and reconstruction algorithm in MDCT assessment of airway wall thickness: A phantom study

    SciTech Connect

    Gomez-Cardona, Daniel; Nagle, Scott K.; Li, Ke; Chen, Guang-Hong; Robinson, Terry E.

    2015-10-15

    Purpose: Wall thickness (WT) is an airway feature of great interest for the assessment of morphological changes in the lung parenchyma. Multidetector computed tomography (MDCT) has recently been used to evaluate airway WT, but the potential risk of radiation-induced carcinogenesis—particularly in younger patients—might limit a wider use of this imaging method in clinical practice. The recent commercial implementation of the statistical model-based iterative reconstruction (MBIR) algorithm, instead of the conventional filtered back projection (FBP) algorithm, has enabled considerable radiation dose reduction in many other clinical applications of MDCT. The purpose of this work was to study the impact of radiation dose and MBIR in the MDCT assessment of airway WT. Methods: An airway phantom was scanned using a clinical MDCT system (Discovery CT750 HD, GE Healthcare) at 4 kV levels and 5 mAs levels. Both FBP and a commercial implementation of MBIR (Veo{sup TM}, GE Healthcare) were used to reconstruct CT images of the airways. For each kV–mAs combination and each reconstruction algorithm, the contrast-to-noise ratio (CNR) of the airways was measured, and the WT of each airway was measured and compared with the nominal value; the relative bias and the angular standard deviation in the measured WT were calculated. For each airway and reconstruction algorithm, the overall performance of WT quantification across all of the 20 kV–mAs combinations was quantified by the sum of squares (SSQs) of the difference between the measured and nominal WT values. Finally, the particular kV–mAs combination and reconstruction algorithm that minimized radiation dose while still achieving a reference WT quantification accuracy level was chosen as the optimal acquisition and reconstruction settings. Results: The wall thicknesses of seven airways of different sizes were analyzed in the study. Compared with FBP, MBIR improved the CNR of the airways, particularly at low radiation dose

  15. High vancomycin MICs within the susceptible range in Staphylococcus aureus bacteraemia isolates are associated with increased cell wall thickness and reduced intracellular killing by human phagocytes.

    PubMed

    Falcón, Rocío; Martínez, Alba; Albert, Eliseo; Madrid, Silvia; Oltra, Rosa; Giménez, Estela; Soriano, Mario; Vinuesa, Víctor; Gozalbo, Daniel; Gil, María Luisa; Navarro, David

    2016-05-01

    Vancomycin minimum inhibitory concentrations (MICs) at the upper end of the susceptible range for Staphylococcus aureus have been associated with poor clinical outcomes of bloodstream infections. We tested the hypothesis that high vancomycin MICs in S. aureus bacteraemia isolates are associated with increased cell wall thickness and suboptimal bacterial internalisation or lysis by human phagocytes. In total, 95 isolates were evaluated. Original vancomycin MICs were determined by Etest. The susceptibility of S. aureus isolates to killing by phagocytes was assessed in a human whole blood assay. Internalisation of bacterial cells by phagocytes was investigated by flow cytometry. Cell wall thickness was evaluated by transmission electron microscopy. Genotypic analysis of S. aureus isolates was performed using a DNA microarray system. Vancomycin MICs were significantly higher (P=0.006) in isolates that were killed suboptimally (killing index <60%) compared with those killed efficiently (killing index >70%) and tended to correlate inversely (P=0.08) with the killing indices. Isolates in both killing groups were internalised by human neutrophils and monocytes with comparable efficiency. The cell wall was significantly thicker (P=0.03) in isolates in the low killing group. No genotypic differences were found between the isolates in both killing groups. In summary, high vancomycin MICs in S. aureus bacteraemia isolates were associated with increased cell wall thickness and reduced intracellular killing by phagocytes.

  16. Plastic Response of Tracheids in Pinus pinaster in a Water-Limited Environment: Adjusting Lumen Size instead of Wall Thickness

    PubMed Central

    Carvalho, Ana; Nabais, Cristina; Vieira, Joana; Rossi, Sergio; Campelo, Filipe

    2015-01-01

    The formation of wood results from cambial activity and its anatomical properties reflect the variability of environmental conditions during the growing season. Recently, it was found that wood density variations in conifers growing under cold-limited environment result from the adjustment of cell wall thickness (CWT) to temperature. Additionally, it is known that intra-annual density fluctuations (IADFs) are formed in response to precipitation after the summer drought. Although IADFs are frequent in Mediterranean conifers no study has yet been conducted to determine if these structures result from the adjustment of lumen diameter (LD) or CWT to soil water availability. Our main objective is to investigate the intra-ring variation of wood anatomical features (LD and CWT) in Pinus pinaster Ait. growing under a water-limited environment. We compared the tracheidograms of LD and CWT for the years 2010–2013 in P. pinaster growing in the west coast of Portugal. Our results suggest a close association between LD and soil moisture content along the growing season, reinforcing the role of water availability in determining tracheid size. Compared with CWT, LD showed a higher intra- and inter-annual variability suggesting its strong adjustment value to variations in water availability. The formation of a latewood IADF appears to be predisposed by higher rates of cell production in spring and triggered by early autumn precipitation. Our findings reinforce the crucial role of water availability on cambial activity and wood formation in Mediterranean conifers, and emphasize the high plasticity of wood anatomical features under Mediterranean climate. PMID:26305893

  17. Plastic Response of Tracheids in Pinus pinaster in a Water-Limited Environment: Adjusting Lumen Size instead of Wall Thickness.

    PubMed

    Carvalho, Ana; Nabais, Cristina; Vieira, Joana; Rossi, Sergio; Campelo, Filipe

    2015-01-01

    The formation of wood results from cambial activity and its anatomical properties reflect the variability of environmental conditions during the growing season. Recently, it was found that wood density variations in conifers growing under cold-limited environment result from the adjustment of cell wall thickness (CWT) to temperature. Additionally, it is known that intra-annual density fluctuations (IADFs) are formed in response to precipitation after the summer drought. Although IADFs are frequent in Mediterranean conifers no study has yet been conducted to determine if these structures result from the adjustment of lumen diameter (LD) or CWT to soil water availability. Our main objective is to investigate the intra-ring variation of wood anatomical features (LD and CWT) in Pinus pinaster Ait. growing under a water-limited environment. We compared the tracheidograms of LD and CWT for the years 2010-2013 in P. pinaster growing in the west coast of Portugal. Our results suggest a close association between LD and soil moisture content along the growing season, reinforcing the role of water availability in determining tracheid size. Compared with CWT, LD showed a higher intra- and inter-annual variability suggesting its strong adjustment value to variations in water availability. The formation of a latewood IADF appears to be predisposed by higher rates of cell production in spring and triggered by early autumn precipitation. Our findings reinforce the crucial role of water availability on cambial activity and wood formation in Mediterranean conifers, and emphasize the high plasticity of wood anatomical features under Mediterranean climate.

  18. Chest wall thickness and decompression failure: A systematic review and meta-analysis comparing anatomic locations in needle thoracostomy.

    PubMed

    Laan, Danuel V; Vu, Trang Diem N; Thiels, Cornelius A; Pandian, T K; Schiller, Henry J; Murad, M Hassan; Aho, Johnathon M

    2016-04-01

    Current Advanced Trauma Life Support guidelines recommend decompression for thoracic tension physiology using a 5-cm angiocatheter at the second intercostal space (ICS) on the midclavicular line (MCL). High failure rates occur. Through systematic review and meta-analysis, we aimed to determine the chest wall thickness (CWT) of the 2nd ICS-MCL, the 4th/5th ICS at the anterior axillary line (AAL), the 4th/5th ICS mid axillary line (MAL) and needle thoracostomy failure rates using the currently recommended 5-cm angiocatheter. A comprehensive search of several databases from their inception to July 24, 2014 was conducted. The search was limited to the English language, and all study populations were included. Studies were appraised by two independent reviewers according to a priori defined PRISMA inclusion and exclusion criteria. Continuous outcomes (CWT) were evaluated using weighted mean difference and binary outcomes (failure with 5-cm needle) were assessed using incidence rate. Outcomes were pooled using the random-effects model. The search resulted in 34,652 studies of which 15 were included for CWT analysis, 13 for NT effectiveness. Mean CWT was 42.79 mm (95% CI, 38.78-46.81) at 2nd ICS-MCL, 39.85 mm (95% CI, 28.70-51.00) at MAL, and 34.33 mm (95% CI, 28.20-40.47) at AAL (P=.08). Mean failure rate was 38% (95% CI, 24-54) at 2nd ICS-MCL, 31% (95% CI, 10-64) at MAL, and 13% (95% CI, 8-22) at AAL (P=.01). Evidence from observational studies suggests that the 4th/5th ICS-AAL has the lowest predicted failure rate of needle decompression in multiple populations. Level 3 SR/MA with up to two negative criteria. Therapeutic. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Chest Wall Thickness and Decompression Failure: A Systematic Review and Meta-analysis Comparing Anatomic Locations in Needle Thoracostomy

    PubMed Central

    Laan, Danuel V.; Vu, Trang Diem N.; Thiels, Cornelius A.; Pandian, T. K.; Schiller, Henry J.; Murad, M. Hassan; Aho, Johnathon M.

    2015-01-01

    Introduction Current Advanced Trauma Life Support guidelines recommend decompression for thoracic tension physiology using a 5-cm angiocatheter at the second intercostal space (ICS) on the midclavicular line (MCL). High failure rates occur. Through systematic review and meta-analysis, we aimed to determine the chest wall thickness (CWT) of the 2nd ICS-MCL, the 4th/5th ICS at the anterior axillary line (AAL), the 4th/5th ICS mid axillary line (MAL) and needle thoracostomy failure rates using the currently recommended 5-cm angiocatheter. Methods A comprehensive search of several databases from their inception to July 24, 2014 was conducted. The search was limited to the English language, and all study populations were included. Studies were appraised by two independent reviewers according to a priori defined PRISMA inclusion and exclusion criteria. Continuous outcomes (CWT) were evaluated using weighted mean difference and binary outcomes (failure with 5-cm needle) were assessed using incidence rate. Outcomes were pooled using the random-effects model. Results The search resulted in 34,652 studies of which 15 were included for CWT analysis, 13 for NT effectiveness. Mean CWT was 42.79 mm (95% CI, 38.78–46.81) at 2nd ICS-MCL, 39.85 mm (95% CI, 28.70–51.00) at MAL, and 34.33 mm (95% CI, 28.20–40.47) at AAL (P=0.08). Mean failure rate was 38% (95% CI, 24–54) at 2nd ICS-MCL, 31% (95% CI, 10–64) at MAL, and 13% (95% CI, 8–22) at AAL (P=0.01). Conclusion Evidence from observational studies suggests that the 4th/5th ICS-AAL has the lowest predicted failure rate of needle decompression in multiple populations. PMID:26724173

  20. Differential impact of left ventricular mass and relative wall thickness on cardiovascular prognosis in diabetic and nondiabetic hypertensive subjects.

    PubMed

    Eguchi, Kazuo; Ishikawa, Joji; Hoshide, Satoshi; Ishikawa, Shizukiyo; Pickering, Thomas G; Schwartz, Joseph E; Homma, Shunichi; Shimada, Kazuyuki; Kario, Kazuomi

    2007-07-01

    Cardiovascular prognostic significance of relative wall thickness (RWT) in patients with diabetes has not been reported although concentric hypertrophy is common in diabetic patients. This study was conducted to test the hypothesis that the prognostic significance of different measures of left ventricular (LV) geometric change, principally LV mass index (LVMI) and RWT, would be different in diabetic patients compared with nondiabetic individuals among Japanese hypertensive subjects. Ambulatory blood pressure monitoring and echocardiography were performed in 400 uncomplicated hypertensive individuals at baseline, of whom 379 (157 with diabetes and 222 without diabetes; mean age 67.8 +/- 8.8 years) were successfully followed up for 63 +/- 26 months to document cardiovascular events. We dichotomized LVMI and RWT to the highest quartile vs other 3 quartiles for further categoric analyses in diabetic and nondiabetic patients. Fifty-three cardiovascular events occurred during the follow-up period. With Kaplan-Meier analysis, both diabetic and nondiabetic patients with the highest quartile of LVMI showed a significantly higher incidence of cardiovascular vents. However, the highest quartile of RWT was associated with cardiovascular events only in diabetic subjects. With Cox regression analyses controlling for age, sex, body mass index, serum creatinine, triglycerides, and clinic systolic blood pressure, RWT (per 0.01 change), but not LVMI, was associated with cardiovascular events in diabetic patients (relative risk: 1.06, 95% confidence interval 1.02-1.11; P = .008), whereas LVMI (g/m2), but not RWT, was associated with cardiovascular events in nondiabetic patients (relative risk: 1.02, 95% confidence interval 1.01-1.03; P = .005). In hypertensive subjects with type 2 diabetes mellitus, echocardiographic LV RWT is a predictor of cardiovascular events independent of LV mass and other confounders.

  1. Mean thoracic aortic wall thickness determination by cine MRI with steady-state free precession: validation with dark blood imaging.

    PubMed

    Mensel, Birger; Kühn, Jens-Peter; Schneider, Tobias; Quadrat, Alexander; Hegenscheid, Katrin

    2013-08-01

    To assess the validity and reliability of measuring mean aortic wall thickness (MAWT) of the ascending and descending aorta using cine steady-state free precession (SSFP) imaging compared to dark blood (DB) imaging. DB and SSFP images of the thoracic aorta acquired at 1.5 T in 50 volunteers (26 women, 24 men; mean age: 50.2 ± 13.1 years) were used. MAWT was calculated on DB and SSFP images for the ascending and descending aorta at the level of the right pulmonary artery by two independent observers. Validity was assessed using Bland-Altman analysis, Passing-Bablok regression, and Spearman correlation. Reliability was assessed using Bland-Altman analysis and intraclass coefficients (ICCs). The mean MAWT of the ascending aorta on DB and SSFP images was 1.89 ± 0.21 mm and 1.87 ± 0.20 mm. The measurements for the descending aorta were 1.60 ± 0.22 and 1.63 ± 0.20 mm, respectively. Comparison of DB and SSFP measurements revealed a mean bias of 1.3% (95% limits of agreement (LOA): -7.9, 10.5%) for the ascending and of -2.1% (LOA: -10.5, 6.3%) for the descending aorta. The corresponding regression equation was y = 0.042 + 0.960 × (r = 0.91; P < .0001) and y = 0.118 + 0.939 × (r = 0.95; P < .0001), respectively. Intra- and interobserver variability showed a mean bias of less than 2.0% and LOA of less than ±15.0%. ICCs were greater than or equal to 0.85. MAWT determination in the ascending and descending aorta using cine SSFP sequences is highly valid and reliable compared to DB imaging. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  2. Critical oxide thickness for efficient single-walled carbon nanotube growth on silicon using thin SiO2 diffusion barriers.

    PubMed

    Simmons, Jason M; Nichols, Beth M; Marcus, Matthew S; Castellini, Olivia M; Hamers, Robert J; Eriksson, Mark A

    2006-07-01

    The ability to integrate carbon nanotubes, especially single-walled carbon nanotubes, seamlessly onto silicon would expand their range of applications considerably. Though direct integration using chemical vapor deposition is the simplest method, the growth of single-walled carbon nanotubes on bare silicon and on ultrathin oxides is greatly inhibited due to the formation of a noncatalytic silicide. Using X-ray photoelectron spectroscopy, we show that silicide formation occurs on ultrathin oxides due to thermally activated metal diffusion through the oxide. Silicides affect the growth of single-walled nanotubes more than multi-walled nanotubes due to the increased kinetics at the higher single-walled nanotube growth temperature. We demonstrate that nickel and iron catalysts, when deposited on clean silicon or ultrathin silicon dioxide layers, begin to form silicides at relatively low temperatures, and that by 900 degrees C, all of the catalyst has been incorporated into the silicide, rendering it inactive for subsequent single-walled nanotube growth. We further show that a 4-nm silicon dioxide layer is the minimum diffusion barrier thickness that allows for efficient single-walled nanotube growth.

  3. Accurate method for measurement of pipe wall thickness using a circumferential guided wave generated and detected by a pair of noncontact transducers

    NASA Astrophysics Data System (ADS)

    Nishino, H.; Taniguchi, Y.; Yoshida, K.

    2012-05-01

    A noncontact method of an accurate estimation of a pipe wall thickness using a circumferential (C-) Lamb wave is presented. The C-Lamb waves circling along the circumference of pipes are transmitted and received by the critical angle method using a pair of noncontact air-coupled ultrasonic transducers. For the accurate estimation of a pipe wall thickness, the accurate measurement of the angular wave number that changes minutely owing to the thickness must be achieved. To achieve the accurate measurement, a large number of tone-burst cycles are used so as to superpose the C-Lamb wave on itself along its circumferential orbit. In this setting, the amplitude of the superposed region changes considerably with the angular wave number, from which the wall thickness can be estimated. This paper presents the principle of the method and experimental verifications. As results of the experimental verifications, it was confirmed that the maximum error between the estimates and the theoretical model was less than 10 micrometers.

  4. Displacement damage in the first structural wall of an inertial confinement fusion reactor: dependence on blanket design

    SciTech Connect

    Meier, W.R.

    1984-07-13

    In this study we investigate how the design of the neutron blanket effects the displacement damage rate in the first structural wall (FSW) of an Inertial Confinement Fusion (ICF) reactor. Two generic configurations are examined; in the first, the steel wall is directly exposed to the fusion neutrons, whereas in the second, the steel wall is protected by inner blanket of lithium with an effective thickness of 1-m. The latter represents a HYLIFE-type design, which has been shown to have displacement damage rates an order of magnitude lower than unprotected wall designs. The two basic configurations were varied to show how the dpa rate changes as the result of (1) adding a Li blanket outside the FSW, (2) adding a neutron reflector (graphite) outside the FSW, and (3) changing the position of the inner lithium blanket relative to the FSW. The effects of neutron moderation in the compressed DT-target are also shown, and the unprotected and protected configurations compared.

  5. Behaviour of a New Composite Mesh for the Repair of Full-Thickness Abdominal Wall Defects in a Rabbit Model

    PubMed Central

    Pascual, Gemma; Sotomayor, Sandra; Rodríguez, Marta; Bayon, Yves; Bellón, Juan M.

    2013-01-01

    Introduction Composite biomaterials designed for the repair of abdominal wall defects are composed of a mesh component and a laminar barrier in contact with the visceral peritoneum. This study assesses the behaviour of a new composite mesh by comparing it with two latest-generation composites currently used in clinical practice. Methods Defects (7x5cm) created in the anterior abdominal wall of New Zealand White rabbits were repaired using a polypropylene mesh and the composites: PhysiomeshTM; VentralightTM and a new composite mesh with a three-dimensional macroporous polyester structure and an oxidized collagen/chitosan barrier. Animals were sacrificed on days 14 and 90 postimplant. Specimens were processed to determine host tissue incorporation, gene/protein expression of neo-collagens (RT-PCR/immunofluorescence), macrophage response (RAM-11-immunolabelling) and biomechanical resistance. On postoperative days 7/14, each animal was examined laparoscopically to quantify adhesions between the visceral peritoneum and implant. Results The new composite mesh showed the lowest incidence of seroma in the short term. At each time point, the mesh surface covered with adhesions was greater in controls than composites. By day 14, the implants were fully infiltrated by a loose connective tissue that became denser over time. At 90 days, the peritoneal mesh surface was lined with a stable mesothelium. The new composite mesh induced more rapid tissue maturation than PhysiomeshTM, giving rise to a neoformed tissue containing more type I collagen. In VentralightTM the macrophage reaction was intense and significantly greater than the other composites at both follow-up times. Tensile strengths were similar for each biomaterial. Conclusions All composites showed optimal peritoneal behaviour, inducing good peritoneal regeneration and scarce postoperative adhesion formation. A greater foreign body reaction was observed for VentralightTM. All composites induced good collagen deposition

  6. Application of elastic wave dispersion relations to estimate thermal properties of nanoscale wires and tubes of varying wall thickness and diameter.

    PubMed

    Bifano, Michael F P; Kaul, Pankaj B; Prakash, Vikas

    2010-06-11

    This paper reports dependency of specific heat and ballistic thermal conductance on cross-sectional geometry (tube versus rod) and size (i.e., diameter and wall thickness), in free-standing isotropic non-metallic crystalline nanostructures. The analysis is performed using dispersion relations found by numerically solving the Pochhammer-Chree frequency equation for a tube. Estimates for the allowable phonon dispersion relations within the crystal lattice are obtained by modifying the elastic acoustic dispersion relations so as to account for the discrete nature of the material's crystal lattice. These phonon dispersion relations are then used to evaluate the specific heat and ballistic thermal conductance in the nanostructures as a function of the nanostructure geometry and size. Two major results are revealed in the analysis: increasing the outer diameter of a nanotube while keeping the ratio of the inner to outer tube radius (gamma) fixed increases the total number of available phonon modes capable of thermal population. Secondly, decreasing the wall thickness of a nanotube (i.e., increasing gamma) while keeping its outer diameter fixed, results in a drastic decrease in the available phonon mode density and a reduction in the frequency of the longitudinal and flexural acoustic phonon modes in the nanostructure. The dependency of the nanostructure's specific heat on temperature indicates 1D, 2D, and 3D geometric phonon confinement regimes. Transition temperatures for each phonon confinement regime are shown to depend on both the nanostructure's wall thickness and outer radius. Compared to nanowires (gamma = 0), the frequency reduction of acoustic phonon modes in thinner walled nanotubes (gamma = 0.96) is shown to elevate the ballistic thermal conductance of the thin-walled nanotube between 0.2 and 150 K. At 20 K, the ballistic thermal conductance of the thin-walled nanotube (gamma = 0.96) becomes 300% greater than that of a solid nanowire. For temperatures above

  7. Numerical Study about the Influence of Wall Angle about Main Strains, Thickness Reduction and Forces on Single Point Incremental Forming Process

    NASA Astrophysics Data System (ADS)

    Oleksik, Valentin

    2016-12-01

    The current paper aims to study, using numerical simulation, the influence of the wall angle on the single point incremental forming process. For the analysis there has been used the LS-Dyna software and three explicit dynamic analyses were run for three parts with wall angles of 450, 550 and 650. The factors taken into account are the main strains, the thickness reduction and the forces on three directions. The material data introduced into the simulation were determined based on an uniaxial traction test on an Instron 5587 testing machine and the Aramis system was used as optical extensometer.

  8. Strategy Guideline. Modeling Enclosure Design in Above-Grade Walls

    SciTech Connect

    J. Lstiburek; Ueno, K.; Musunuru, S.

    2016-02-01

    The Strategy Guideline, written by the U.S. Department of Energy's research team Building Science Corporation, 1) describes how to model and interpret results of models for above-grade walls, and 2) analyzes the failure thresholds and criteria for above-grade walls. A library of above-grade walls with historically successful performance was used to calibrate WUFI (Wärme und Feuchte instationär) software models. The information is generalized for application to a broad population of houses within the limits of existing experience.

  9. Numerical design of streamlined tunnel walls for a two-dimensional transonic test

    NASA Technical Reports Server (NTRS)

    Newman, P. A.; Anderson, E. C.

    1978-01-01

    An analytical procedure is discussed for designing wall shapes for streamlined, nonporous, two-dimensional, transonic wind tunnels. It is based upon currently available 2-D inviscid transonic and boundary layer analysis computer programs. Predicted wall shapes are compared with experimental data obtained from the NASA Langley 6 by 19 inch Transonic Tunnel where the slotted walls were replaced by flexible nonporous walls. Comparisons are presented for the empty tunnel operating at a Mach number of 0.9 and for a supercritical test of an NACA 0012 airfoil at zero lift. Satisfactory agreement is obtained between the analytically and experimentally determined wall shapes.

  10. In the femoral artery bifurcation, differences in mean wall shear stress within subjects are associated with different intima-media thicknesses.

    PubMed

    Kornet, L; Hoeks, A P; Lambregts, J; Reneman, R S

    1999-12-01

    In elastic arteries, intima-media thickening is more pronounced in areas with low than with high mean and peak wall shear stress. These findings in elastic arteries are not necessarily representative of the situation in muscular arteries. The former arteries have to store volume energy, whereas the latter are mainly conductive vessels. It was the aim of the present study to investigate noninvasively whether differences in wall shear stress within a muscular artery bifurcation, if any, were associated with different intima-media thicknesses (IMTs). The effect of age on the possible differences was assessed as well. We determined IMT and mean, peak systolic, and the maximum cyclic change in shear stress near the posterior wall in the common (FC) and the superficial (FS) femoral artery 20 to 30 mm from the flow divider in 54 presumed healthy subjects between 21 and 74 years of age. Results were considered in terms of intrasubject differences. Before the study, the reliability of the ultrasonic system to assess wall shear rate and IMT was determined in terms of intrasubject variability. IMT at the posterior wall was significantly larger in the FC than in the FS, probably owing to the significantly lower mean wall shear stress at this site in the FC. The relative differences in IMT and mean wall shear stress between FC and FS were independent of age. The difference in wall shear stress between both arteries can likely be explained by a different influence of reflections. In both the FC and FS, mean, peak systolic, and maximum cyclic change in shear stress near the posterior wall did not change significantly with age, whereas IMT did increase significantly with age.

  11. Coating requirements for an ICF dry-wall design

    SciTech Connect

    Taylor, L.H.; Sucov, E.W.

    1981-06-30

    A new concept for protecting the first wall of an ICF reactor has been developed which relies heavily on a coating to protect the steel tubes which comprise the first wall. This coating must survive the pellet explosion, be ductile, and be compatible with the materials in the ICF pellet. Calculations indicate that tantalum is the best choice for the coating material and that tantalum coated steel tubes can handle fusion thermal powers of 3500 MW in a 10 m radius spherical chamber.

  12. Design, construction, test and evaluation of a frequency scanning radiometer for measuring oil slick thicknesses

    NASA Astrophysics Data System (ADS)

    Hover, G. L.; Murphy, J.; Brown, E. R.; Hogan, G. G.; McMahon, O. B.

    1994-06-01

    Single frequency microwave radiometry has been used to detect and estimate oil slick thicknesses. Because only a single sampling point is used, estimates of oil thickness can become ambiguous. MIT Lincoln Laboratory proposed the concept of using a frequency scanning radiometer to sample multiple points across a frequency band, thus resolving the problem of ambiguities in oil thickness estimation. A laboratory-prototype FSR capable of scanning over Ka-band (26 -40GHz) was designed, built, and tested. The FSR was used in laboratory proof-of-principle testing to (1) measure uniform thickness oil layers under various ambient weather conditions (day, night, clear, cloudy, drizzle, and snow) and different oil types, and (2) measure the phenomenology of non-uniform thickness oil layers and emulsions. Comparisons of measured data sets with theoretical predictions demonstrated that the expected response of oil is consistent regardless of oil type or ambient weather condition. Comparisons of uniform oil layer measurements and non-uniform measurements with theoretical predictions indicate that the radiometric brightness temperature (TB) of the oil above that of water is a function of the percentage of that thickness of oil within the antenna field-of-view. Water/oil emulsions were measured and have a higher TB than a uniform layer of pure oil at the same thickness. Recommendations for FSR modifications and improvements, as well as future collection work are included.

  13. Design And Construction Problems Connected With Ensuring Even Thermal Insulation Of Single-Layer Walls

    NASA Astrophysics Data System (ADS)

    Stawiski, Bohdan

    2015-09-01

    The design of single-layer walls appears to be extremely simple. In the opinion of many designers, the additional insulation of tie beams and balconies continues to solve all problems. However, tests on single-layer walls show that the expressed opinion is not valid. The study quotes the results of tests on single-layer walls with strong signs of freezing. The conducted analysis of the design solution and calculation of the fRsi temperature factor on the internal surface and its comparison with fRsi determined empirically enabled reasons behind failure in the construction of the tested walls to be identified. The study presents problems connected with ensuring uniformity of the temperature field in walls, possibilities for detecting areas susceptible to the development of mold, and protection of partitions from the occurrence of this phenomenon by performing appropriate repair works preceding necessary renovations of the building which takes place after the occurrence of mold on walls and ceilings.

  14. Static load test of Arquin-designed CMU wall.

    SciTech Connect

    Jensen, Richard Pearson; Cherry, Jeffery L.

    2008-12-01

    The Arquin Corporation has developed a new method of constructing CMU (concrete masonry unit) walls. This new method uses polymer spacers connected to steel wires that serve as reinforcing as well as means of accurately placing the spacers so that the concrete block can be dry stacked. The hollows of the concrete block used in constructing the wall are then filled with grout. As part of a New Mexico Small Business Assistance Program (NMSBAP), Sandia National Laboratories conducted a series of tests that statically loaded wall segments to compare the Arquin method to a more traditional method of constructing CMU walls. A total of 12 tests were conducted, three with the Arquin method using a W5 reinforcing wire, three with the traditional method of construction using a number 3 rebar as reinforcing, three with the Arquin method using a W2 reinforcing wire, and three with the traditional construction method but without rebar. The results of the tests showed that the walls constructed with the Arquin method and with a W5 reinforcing wire withstood more load than any of the other three types of walls that were tested.

  15. Computational study of the electromagnetic forces and torques on different ITER first wall designs.

    SciTech Connect

    Kotulski, Joseph Daniel; Garde, Joseph Maurico; Coats, Rebecca Sue; Pasik, Michael Francis; Ulrickson, Michael Andrew

    2009-06-01

    An electromagnetic analysis is performed on different first wall designs for the ITER device. The electromagnetic forces and torques present due to a plasma disruption event are calculated and compared for the different designs.

  16. Pedicled full-thickness abdominal flap combined with skin grafting for the reconstruction of anterior chest wall defect following major electrical burn.

    PubMed

    Zhao, Jing-Chun; Xian, Chun-Jing; Yu, Jia-Ao; Shi, Kai

    2015-02-01

    Successful reconstruction of extensive anterior chest wall defect following major electrical burn represents a very challenging surgery. Herein we report the first case using pedicled full-thickness abdominal flap combined with skin grafting to treat this injury with severe infection and exposure of pericardium and ribs in a Chinese patient. Following the performance of chest debridement to remove necrotic and infected tissues and the injection of broad-spectrum antibiotics to reduce infection, a pedicled full-thickness abdominal flap was used to cover the exposed pericardium and ribs, and skin grafting from the right leg of the patient was done to cover the exposed vital tissues. The patient was followed up for a total of 3·5 years, and satisfactory cosmetic and functional outcomes were obtained without complications. This report provides an effective method for the surgeons who encounter similar cases where reconstruction of extensive anterior chest wall is required.

  17. Fracture resistance of welded thick-walled high-pressure vessels in power plants. Report No. 1. Statistical analysis of defects and fracture resistance of vessel materials

    SciTech Connect

    Gorynin, I.V.; Filatov, V.M.; Ignatov, V.A.; Timofeev, B.T.; Zvezdin, Yu. I.

    1986-07-01

    Data from plant radiographic inspection of reactor vessels and boilers in power plants of 440- and 1000-MW capacity were subjected to statistical analysis. It was found that, given the current technology for making and constructing 440- and 1000-MW power plants, the limiting defect size in the vessels of the plants is no more than 10% of the wall thickness according to the results of statistical analysis. This finding makes it possible to increase the tolerable stresses by a factor of 1.6 compared to the current estimate of resistance to brittle fracture, which presumes the presence of a semielliptical surface crack of a depth corresponding to 25% of the wall thickness. The fracture resistance of steel increase with a decrease in defect size and as a result of the damping capacity of the anticorrosive hardfacing applied.

  18. Fabrication of chitosan single-component microcapsules with a micrometer-thick and layered wall structure by stepwise core-mediated precipitation.

    PubMed

    Han, Yuanyuan; Tong, Weijun; Zhang, Yuying; Gao, Changyou

    2012-02-27

    Incubation of CaCO(3) microparticles in chitosan (CS) solution at pH 5.2 and following with ethylenediaminetetraacetic acid disodium salt (EDTA) treatment resulted in CS single-component microcapsules with an ultra-thick wall structure. Repeating the incubation caused stepwise increase of wall thickness and finally resulted in CS microcapsules with a layered structure. This unique method is mediated by precipitation of CS on the CaCO(3) particles as a result of pH increase caused by the partial dissolution of CaCO(3) . The obtained CS capsules are stable at neutral pH. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Short-axis epicardial volume change is a measure of cardiac left ventricular short-axis function, which is independent of myocardial wall thickness.

    PubMed

    Ugander, Martin; Carlsson, Marcus; Arheden, Håkan

    2010-02-01

    Fractional shortening (FS) by echocardiography is considered to represent the short-axis contribution to the stroke volume (SV), also called short-axis function. However, FS is mathematically coupled to the amount of myocardium, since it rearranges during atrioventricular plane displacement (AVPD). The SV is the sum of the volumes generated by 1) reduction in outer volume of the heart, and 2) inner AVPD. The long-axis contribution to the SV is generated by AVPD, and thus the short-axis contribution is the remaining outer volume change of the heart, which should be unrelated to myocardial wall thickness. We hypothesized that both endocardial and midwall shortening indexed to SV are dependent on myocardial wall thickness, whereas epicardial volume change (EVC) indexed to SV is not. Twelve healthy volunteers (normals), 12 athletes, and 12 patients with dilated cardiomyopathy (ejection fraction < 30%) underwent cine cardiac magnetic resonance imaging. Left ventricular long-axis function was measured as the portion of the SV, in milliliters, generated by AVPD. EVC was defined as SV minus long-axis function. Endocardial and midwall shortening were measured in a midventricular short-axis slice. Endocardial shortening/SV and midwall shortening/SV both varied in relation to end-diastolic myocardial wall thickness (R(2) = 0.16, P = 0.008 and R(2) = 0.14, P = 0.012, respectively), whereas EVC/SV did not (R(2) = 0.00, P = 0.37). FS is dependent on myocardial wall thickness, whereas EVC is not and therefore represents true short-axis function. This is not surprising considering that FS is mainly caused by rearrangement of myocardium secondary to long-axis function. FS is therefore not synonymous with short-axis function.

  20. Wood formation from the base to the crown in Pinus radiata: gradients of tracheid wall thickness, wood density, radial growth rate and gene expression

    Treesearch

    Sheree Cato; Lisa McMillan; Lloyd Donaldson; Thomas Richardson; Craig Echt; Richard Gardner

    2006-01-01

    Wood formation was investigated at five heights along the bole for two unrelated trees of Pinus radiataBoth trees showed clear gradients in wood properties from the base to the crown. Cambial cells at the base of the tree were dividing 3.3-fold slower than those at the crown, while the average thickness of cell walls in wood was highest at the base....

  1. Association of aortic wall thickness on contrast-enhanced chest CT with major cerebro-cardiac events.

    PubMed

    Tresoldi, Silvia; Di Leo, Giovanni; Zoffoli, Elena; Munari, Alice; Primolevo, Alessandra; Cornalba, Gianpaolo; Sardanelli, Francesco

    2014-11-01

    There is a significant association between aortic atherosclerosis and previous major cardiovascular events. Particularly, thoracic aortic atherosclerosis is closely related to the degree of coronary and carotid artery disease. Thus, there is a rationale for screening the thoracic aorta in patients who undergo a chest computed tomography (CT) for any clinical question, in order to detect patients at increased risk of cerebro-cardiovascular (CCV) events. To estimate the association between either thoracic aortic wall thickness (AWT) or aortic total calcium score (ATCS) and CCV events. One hundred and forty-eight non-cardiac patients (78 men; 67 ± 12 years) underwent chest contrast-enhanced multidetector CT (MDCT). The AWT was measured at the level of the left atrium (AWTref) and at the maximum AWT (AWTmax). Correlation with clinical CCV patients' history was estimated. The value of AWTmax and of a semi-quantitative ATCS as a marker for CCV events was assessed using receiver-operating characteristic curve (ROC) analysis and multivariate regression analysis. Out of 148 patients, 59% reported sedentary lifestyle, 44% hypertension, 32% smoking, 23% hypercholesterolemia, 13% family history of cardiac disease, 12% diabetes, and 10% BMI ≥ 30 kg/m(2); 9% reported myocardial infarction, 8% aortic aneurism, 8% myocardial revascularization, and 2% ischemic stroke. Twenty-six percent of patients had a medium-to-high ATCS. Both AWTmax and AWTref correlated with hypertension and age (P < 0.002). At the ROC analysis, a 4.8 mm threshold was associated to a 90% specificity and an odds ratio of 6.3 (AUC = 0.735). Assuming as threshold the AWTmax median value (4.3 mm) of patients who suffered from at least one CCV event in their history, a negative predictive value of 90%, a RR of 3.6 and an OR of 6.3 were found. At the multivariate regression analysis, AWTmax was the only independent variable associated to the frequency of CCV events. Patients with increased thoracic

  2. Optimal cure cycle design for autoclave processing of thick composites laminates: A feasibility study

    NASA Technical Reports Server (NTRS)

    Hou, Jean W.

    1985-01-01

    The thermal analysis and the calculation of thermal sensitivity of a cure cycle in autoclave processing of thick composite laminates were studied. A finite element program for the thermal analysis and design derivatives calculation for temperature distribution and the degree of cure was developed and verified. It was found that the direct differentiation was the best approach for the thermal design sensitivity analysis. In addition, the approach of the direct differentiation provided time histories of design derivatives which are of great value to the cure cycle designers. The approach of direct differentiation is to be used for further study, i.e., the optimal cycle design.

  3. Assessing the thickness of the vaginal wall and vaginal mucosa in pre-menopausal versus post-menopausal women by transabdominal ultrasound: A feasibility study.

    PubMed

    Balica, Adrian; Wald-Spielman, Daniella; Schertz, Katherine; Egan, Susan; Bachmann, Gloria

    2017-08-01

    As life expectancy increases, the number of women reporting adverse genito-urinary symptoms (genitourinary syndrome of menopause; GSM) from menopause, including vaginal dryness and sexual pain, also will increase. Current objective measurements of vaginal atrophy such as maturation index require vaginal swabs and are invasive; at present, no minimally invasive measurements exist. The purpose of this study was to assess whether total vaginal wall thickness (TVT) and total vaginal mucosa thickness (TMT) as measured by transabdominal ultrasound could qualify as additional objective markers of vaginal wall thinning which could be related to menopausal status. Women presenting for pelvic ultrasound had a transabdominal ultrasound scan performed to measure TVT and TMT at the level of the bladder trigone. In addition, a transvaginal endometrial lining thickness was measured. The ultrasound measurement data from 76 participants showed that there was a significant difference in the mean value for TVT and endometrial lining between pre- and post-menopausal women. The same difference in mean was not observed for TMT. TVT may be a reliable measure of vaginal thinning, which worsens with estrogen decline. These preliminary data also suggest that TMT does not have the same correlation as the TVT measurement. A larger sample is needed to further assess the usefulness and sensitivity of these measures and whether there is clinical and/or research usefulness in obtaining vaginal wall measurements by transabdominal ultrasound. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Decoupling the effects of the size, wall thickness, and porosity of curcumin-loaded chitosan nanocapsules on their anticancer efficacy: size is the winner.

    PubMed

    Goethals, Emma C; Elbaz, Abdulkareem; Lopata, Andreas L; Bhargava, Suresh K; Bansal, Vipul

    2013-01-15

    Polymer nanocapsules have gained an important place as drug delivery vehicles for a myriad of biomedical applications. However, the influence of nanocapsule size, wall thickness, and porosity toward controlling the drug delivery efficiency of nanocapsular systems is not well understood. We report a facile template-mediated approach for the development of near monodispersed chitosan nanocapsules of different sizes, wall thicknesses, and porosities in a controllable manner. The ability of this approach to finely tune the structural characteristics of chitosan nanocapsules enabled us to systematically investigate the influence of capsule size, wall thickness, and porosity on their efficiency as drug delivery vehicles against mouse mastocytoma cells after loading them with curcumin, a natural lipophilic anticancer drug. This study establishes an important finding in the field of nanocapsule-based drug delivery systems that although several structural characteristics of a nanocapsule might be responsible in influencing their efficiency as a chemotherapeutic carrier, the size of the nanocapsules is likely to play the most important role in dictating the chemotherapeutic efficiency of such systems.

  5. Optimum design of the carbon fiber thin-walled baffle for the space-based camera

    NASA Astrophysics Data System (ADS)

    Yan, Yong; Song, Gu; Yuan, An; Jin, Guang

    2011-08-01

    The thin-walled baffle design of the space-based camera is an important job in the lightweight space camera research task for its stringent quality requirement and harsh mechanical environment especially for the thin-walled baffle of the carbon fiber design. In the paper, an especially thin-walled baffle of the carbon fiber design process was described and it is sound significant during the other thin-walled baffle design of the space camera. The designer obtained the design margin of the thin-walled baffle that structural stiffness and strength can tolerated belong to its development requirements through the appropriate use of the finite element analysis of the walled parameters influence sensitivity to its structural stiffness and strength. And the designer can determine the better optimization criterion of thin-walled baffle during the geometric parameter optimization process in such guiding principle. It sounds significant during the optimum design of the thin-walled baffle of the space camera. For structural stiffness and strength of the carbon fibers structure which can been designed, the effect of the optimization will be more remarkable though the optional design of the parameters chose. Combination of manufacture process and design requirements the paper completed the thin-walled baffle structure scheme selection and optimized the specific carbon fiber fabrication technology though the FEM optimization, and the processing cost and process cycle are retrenchment/saved effectively in the method. Meanwhile, the weight of the thin-walled baffle reduced significantly in meet the design requirements under the premise of the structure. The engineering prediction had been adopted, and the related result shows that the thin-walled baffle satisfied the space-based camera engineering practical needs very well, its quality reduced about 20%, the final assessment index of the thin-walled baffle were superior to the overall design requirements significantly. The design

  6. Reconstruction of a four-quadrant full-thickness abdominal wall defect after removal and debridement of an infected mesh hernioplasty.

    PubMed

    Schmitz, C; Schramm, S; Hankiss, J

    2011-02-01

    This case-report shows our experience with a patient, who underwent mesh hernioplasty followed by infection of the mesh and full-thickness loss of the abdominal wall after debridement due to necrosis. The anamnesis included generalised arteriosclerosis, chronic nicotine and alcohol abuse and recurring wound-healing disorders after surgical procedures. The initial infection was treated by radical debridement, targeted antibiotics and V.A.C.(®) Therapy. After this, a staged plastic reconstructive procedure with four pedicled flaps was performed. The functional integrity of the abdominal wall was completely re-established. The patient was able to continue her occupation as a facility manager. Although the use of free flaps is very common in modern plastic and reconstructive surgery, procedures such as pedicled flaps still have their significance for special indications. In this case, a full recovery of the abdominal wall with autologous tissue was successful under difficult vascular conditions by using local flaps.

  7. Effect of botulinum toxin type A in lateral abdominal wall muscles thickness and length of patients with midline incisional hernia secondary to open abdomen management.

    PubMed

    Ibarra-Hurtado, T R; Nuño-Guzmán, C M; Miranda-Díaz, A G; Troyo-Sanromán, R; Navarro-Ibarra, R; Bravo-Cuéllar, L

    2014-10-01

    Abdominal wall hernia secondary to open abdomen management represents a surgical challenge. The hernia worsens due to lateral muscle retraction. Our objective was to evaluate if Botulinum Toxin Type A (BTA) application in lateral abdominal wall muscles modifies its thickness and length. A clinical trial of male trauma patients with hernia secondary to open abdomen management was performed from January 2009 to July 2011. Thickness and length of lateral abdominal muscles were measured by a basal Computed Tomography and 1 month after BTA application. A dosage of 250 units of BTA was applied at five points at each side between the external and internal oblique muscles under ultrasonographic guidance. Statistical analysis for differences between basal and after BTA application measures was performed by a paired Student's t test (significance: p < 0.05). Seventeen male patients with a mean age of 35 years were included. There were muscle measure modifications in all the patients. Left muscle thickness: mean reduction of 1 ± 0.55 cm (p < 0.001). Right muscle thickness: mean reduction of 1.00 ± 0.49 cm (p < 0.001). Left muscle length: mean increase of 2.44 ± 1.22 cm (p < 0.001). Right muscle length: mean increase of 2.59 ± 1.38 cm (p < 0.001). No complications secondary to BTA or recurrences at mean follow-up of 49 months were observed. BTA application in lateral abdominal muscles decreases its thickness and increases its length in abdominal wall hernia patients secondary to open abdomen management.

  8. Extremal states of energy of a double-layered thick-walled tube - application to residually stressed arteries.

    PubMed

    Waffenschmidt, Tobias; Menzel, Andreas

    2014-01-01

    Various biological tissues are designed to optimally support external loads for complex geometries and mechanobiological structures. This results in complex microstructures of such materials. The design of, for instance, (healthy) arteries, which are in the focus of this work, is characterised by a residually stressed fibre-reinforced multi-layered composite with highly non-linear elastic response. The complex interaction of material properties with the geometry and residual stress effects enables the optimal support under different blood pressures, respectively blood flow, within the vessel. The fibres reinforcing the arterial wall, as well as residual stresses present in the vessel, strongly influence its overall behaviour and performance. Turn-over and remodelling processes of the collagenous fibres occurring in the respective layers - either resulting from natural growth phenomena or from artificially induced changes in loading condition such as stent deployment - support the optimisation of the multi-layered composite structure of arteries for the particular loading conditions present in the artery. Within this contribution, the overall energetic properties of an artery are discussed by means of the inflation, bending and extension of a double-layered cylindrical tube. Different states of residual stresses and different fibre orientations are considered so that, for instance, representative fibre angles that result in extremal states of the total potential energy can be identified. In view of turn-over and remodelling processes, these orientations are considered to constitute preferred directions of fibre alignment. In summary, the main goal of this work is to calculate optimal material, structural and loading parameters by concepts of energy-minimisation. Several numerical studies show that the obtained values - such as the fibre orientations, the residual axial stretch and the opening angle - are in good agreement with respective physiological parameters

  9. [Design and implementation of projection-initialized wall filter in ultrasonic imaging].

    PubMed

    Wang, Peidong; Shen, Yi; Wang, Yan

    2008-04-01

    Wall filtering is a key technology in ultrasound color flow imaging system. Without efficient suppression of wall signal originating from stationary and moving tissue, low velocity blood flow cannot be measured, and the estimates of higher velocities will have a large bias. Among the various wall filters, the projection-initialized infinite impulse response (IIR) wall filter has narrow transition bandwidth and high stopband suppression ratio; it is superior to other wall filters. At present, the related literatures are only limited to theoretical research on this kind of filter, and no feasible design and implementation methods are reported. In this paper, a new design and implementation scheme for the projection-initialized filter is proposed, which transforms the filtering process to matrix multiplications. The proposed scheme is realized on programmable logic devices. Experimental results show that it is a simple and effective implementation method for projection-initialized IIR filter, and it is superior to conventional wall filters.

  10. Thickness design, fabrication, and evaluation of 100-MHz polyurea ultrasonic transducer.

    PubMed

    Nakazawa, Marie; Tabaru, Masaya; Aoyagi, Takahiro; Nakamura, Kentaro; Ueha, Sadayuki

    2013-10-01

    In this paper, we present a polyurea transducer that works at 100 MHz under water. The transducer was designed using an equivalent circuit model so that an aluminum (top)-polyurea-aluminum (bottom)-polyimide layer had a resonant frequency of 100 MHz and output sound pressure became maximum at that frequency. The thicknesses of the top aluminum electrode, polyurea, and bottom aluminum electrode were determined to be 3.3, 3.5, and 1.7 μm, respectively. A 100-MHz polyurea transducer with the designed thickness was fabricated using deposition equipment. To evaluate the performance of the designed and fabricated polyurea transducer, transmission-reception experiments with pulsed and burst waves were carried out. The results show that transmitting and receiving ultrasounds at a frequency of 100 MHz are possible as expected with the thickness design. To evaluate actual use, B-mode imaging of an onion was also performed using the transducer, which was formed into a line-focused shape. The result shows that the outer layer of the onion, of 0.1 to 0.2 mm thickness, was successfully imaged.

  11. Design Limits for Precast Concrete Sandwich Walls Subjected to External Explosions (PREPRINT)

    DTIC Science & Technology

    2010-02-01

    AFRL-RX-TY-TP-2010-0013 PREPRINT DESIGN LIMITS FOR PRECAST CONCRETE SANDWICH WALLS SUBJECTED TO EXTERNAL EXPLOSIONS Clay Naito and... Precast Concrete Sandwich Walls Subjected to External Explosions (PREPRINT) FA4819-09-C-0032 62012F 4918 C1 Q103013 *Naito, Clay; *Beacraft, Mark...Structures Congress, 12-14 May 2010, in Orlando FL. The use of precast /prestressed concrete and tilt‐up concrete for exterior walls is common

  12. Synthesis study of nondestructive testing devices for use in overlay thickness design of flexible pavements

    NASA Astrophysics Data System (ADS)

    Smith, R. E.; Lytton, R. L.

    1984-04-01

    A ready reference for highway engineers who are interested in purchasing nondestructive testing (NDT) equipment for use in designing overlays for flexible pavements was prepared. All commercially available equipment is described. Information includes basic descriptions plus current prices quoted by the manufacturers/distributors. To determine user comments, a questionnaire was sent to nine State agencies, and one Federal agency. The responses to these questionnaires are summarized. Overlay thickness design procedures for flexible pavements are reviewed. Important components related to the use of NDT deflection measuremnts in overlay design are identified and addressed. Summary tables of equipment characteristics and overlay design procedures are presented.

  13. Plant cell walls throughout evolution: towards a molecular understanding of their design principles

    SciTech Connect

    Sarkar, Purbasha; Bosneaga, Elena; Auer, Manfred

    2009-02-16

    Throughout their life, plants typically remain in one location utilizing sunlight for the synthesis of carbohydrates, which serve as their sole source of energy as well as building blocks of a protective extracellular matrix, called the cell wall. During the course of evolution, plants have repeatedly adapted to their respective niche,which is reflected in the changes of their body plan and the specific design of cell walls. Cell walls not only changed throughout evolution but also are constantly remodelled and reconstructed during the development of an individual plant, and in response to environmental stress or pathogen attacks. Carbohydrate-rich cell walls display complex designs, which together with the presence of phenolic polymers constitutes a barrier for microbes, fungi, and animals. Throughout evolution microbes have co-evolved strategies for efficient breakdown of cell walls. Our current understanding of cell walls and their evolutionary changes are limited as our knowledge is mainly derived from biochemical and genetic studies, complemented by a few targeted yet very informative imaging studies. Comprehensive plant cell wall models will aid in the re-design of plant cell walls for the purpose of commercially viable lignocellulosic biofuel production as well as for the timber, textile, and paper industries. Such knowledge will also be of great interest in the context of agriculture and to plant biologists in general. It is expected that detailed plant cell wall models will require integrated correlative multimodal, multiscale imaging and modelling approaches, which are currently underway.

  14. Plant cell walls throughout evolution: towards a molecular understanding of their design principles.

    PubMed

    Sarkar, Purbasha; Bosneaga, Elena; Auer, Manfred

    2009-01-01

    Throughout their life, plants typically remain in one location utilizing sunlight for the synthesis of carbohydrates, which serve as their sole source of energy as well as building blocks of a protective extracellular matrix, called the cell wall. During the course of evolution, plants have repeatedly adapted to their respective niche, which is reflected in the changes of their body plan and the specific design of cell walls. Cell walls not only changed throughout evolution but also are constantly remodelled and reconstructed during the development of an individual plant, and in response to environmental stress or pathogen attacks. Carbohydrate-rich cell walls display complex designs, which together with the presence of phenolic polymers constitutes a barrier for microbes, fungi, and animals. Throughout evolution microbes have co-evolved strategies for efficient breakdown of cell walls. Our current understanding of cell walls and their evolutionary changes are limited as our knowledge is mainly derived from biochemical and genetic studies, complemented by a few targeted yet very informative imaging studies. Comprehensive plant cell wall models will aid in the re-design of plant cell walls for the purpose of commercially viable lignocellulosic biofuel production as well as for the timber, textile, and paper industries. Such knowledge will also be of great interest in the context of agriculture and to plant biologists in general. It is expected that detailed plant cell wall models will require integrated correlative multimodal, multiscale imaging and modelling approaches, which are currently underway.

  15. A case report on a full-thickness chest wall reconstruction with polypropylene mesh and stainless steel mesh concurrently using a transverse rectus abdominis myocutaneous flap.

    PubMed

    Yoshino, Naoyuki; Yamauchi, Shigeo; Akimoto, Masataka; Hisayoshi, Takao; Koizumi, Kiyoshi; Shimizu, Kazuo

    2006-12-01

    A full-thickness chest wall resection requires subsequent chest wall reconstruction. A chest wall resection and reconstruction was performed using a transverse rectus abdominis myocutaneous (TRAM) flap, together with polypropylene mesh (Marlex mesh) and stainless steel mesh (SSM). A 71-year-old man was diagnosed as having recurrent lung cancer in the chest wall, and underwent surgical resection. Marlex mesh was sutured to the posterior wall of the surgical defect. A portion of the SSM was adjusted to the size of the defect and cut out. Its edges were folded to make the portion into a plate. This SSM plate was placed anteriorly to the Marlex mesh and sutured to the ribs. The Marlex mesh was folded back on the SSM plate by 2 cm and fixed. After the above procedures, a left-sided TRAM flap was raised through a subcutaneous tunnel up to the defect and sutured to the region. The patient was discharged from hospital 19 days postoperatively. The wound was fine and he had no flail chest or dyspnea, and carcinomatous pain resolved.

  16. The design and performance of axially symmetrical contoured wall diffusers employing suction boundary layer control

    NASA Technical Reports Server (NTRS)

    Nelson, C. D., Jr.; Hudson, W. G.; Yang, T.

    1974-01-01

    This paper presents a procedure for the design and the performance prediction of axially symmetrical contoured wall diffusers employing suction boundary layer control. An inverse problem approach was used in the potential flow design of the diffuser wall contours. The experimentally observed flow characteristics and the stability of flows within the diffuser are also described. Guidelines for the design of low suction (less than 10 percent of the inlet flow) and thus high effectiveness contoured wall diffusers are also provided based on the results of the experimental program.

  17. Hypertensive heart disease versus hypertrophic cardiomyopathy: multi-parametric cardiovascular magnetic resonance discriminators when end-diastolic wall thickness ≥ 15 mm.

    PubMed

    Rodrigues, Jonathan C L; Rohan, Stephen; Ghosh Dastidar, Amardeep; Harries, Iwan; Lawton, Christopher B; Ratcliffe, Laura E; Burchell, Amy E; Hart, Emma C; Hamilton, Mark C K; Paton, Julian F R; Nightingale, Angus K; Manghat, Nathan E

    2017-03-01

    European guidelines state left ventricular (LV) end-diastolic wall thickness (EDWT) ≥15mm suggests hypertrophic cardiomyopathy (HCM), but distinguishing from hypertensive heart disease (HHD) is challenging. We identify cardiovascular magnetic resonance (CMR) predictors of HHD over HCM when EDWT ≥15mm. 2481 consecutive clinical CMRs between 2014 and 2015 were reviewed. 464 segments from 29 HCM subjects with EDWT ≥15mm but without other cardiac abnormality, hypertension or renal impairment were analyzed. 432 segments from 27 HHD subjects with EDWT ≥15mm but without concomitant cardiac pathology were analyzed. Magnitude and location of maximal EDWT, presence of late gadolinium enhancement (LGE), LV asymmetry (>1.5-fold opposing segment) and systolic anterior motion of the mitral valve (SAM) were measured. Multivariate logistic regression was performed. Significance was defined as p<0.05. HHD and HCM cohorts were age-/gender-matched. HHD had significantly increased indexed LV mass (110±27g/m(2) vs. 91±31g/m(2), p=0.016) but no difference in site or magnitude of maximal EDWT. Mid-wall LGE was significantly more prevalent in HCM. Elevated indexed LVM, mid-wall LGE and absence of SAM were significant multivariate predictors of HHD, but LV asymmetry was not. Increased indexed LV mass, absence of mid-wall LGE and absence of SAM are better CMR discriminators of HHD from HCM than EDWT ≥15mm. • Hypertrophic cardiomyopathy (HCM) is often diagnosed with end-diastolic wall thickness ≥15mm. • Hypertensive heart disease (HHD) can be difficult to distinguish from HCM. • Retrospective case-control study showed that location and magnitude of EDWT are poor discriminators. • Increased left ventricular mass and midwall fibrosis are independent predictors of HHD. • Cardiovascular magnetic resonance parameters facilitate a better discrimination between HHD and HCM.

  18. Design of SC walls and slabs for impulsive loading

    SciTech Connect

    Varma, Amit H.

    2015-11-11

    Reinforced concrete (RC) structures have historically been the preferred choice for blast resistant structures because of their mass and the ductility provided by steel reinforcement. Steel-plate composite (SC) walls are a viable alternative to RC for protecting the infrastructure against explosive threats. SC structures consist of two steel faceplates with a plain concrete core between them. The steel faceplates are anchored to the concrete using stud anchors and connected to each other using tie bars. SC structures provide mass from the concrete infill and ductility from the continuous external steel faceplates. This dissertation presents findings and recommendations from experimental and analytical investigations of the performance of SC walls subjected to far-field blast loads.

  19. Modeling Enclosure Design in Above-Grade Walls

    SciTech Connect

    Lstiburek, J.; Ueno, K.; Musunuru, S.

    2016-03-01

    Building Science Corporation modeled typically well-performing wall assemblies using Wärme und Feuchte instationär (WUFI) Version 5.3 software and demonstrated that these models agree with historic experience when calibrated and modeled correctly. This technical report provides a library of WUFI modeling input data and results. Within the limits of existing experience, this information can be generalized for applications to a broad population of houses.

  20. Interfacial heat transfer in squeeze casting of magnesium alloy AM60 with variation of applied pressures and casting wall-thicknesses

    NASA Astrophysics Data System (ADS)

    Zhang, Xuezhi; Fang, Li; Sun, Zhizhong; Hu, Henry; Nie, Xueyuan; Tjong, Jimi

    2016-10-01

    The heat transfer coefficient at the casting-die interface is the most important factor on the solidification process. With the 75-ton hydraulic press machine and P20 steel die mold, 5-step castings of magnesium alloy AM60 with different wall-thicknesses (3, 5, 8, 12, 20 mm) were poured under various hydraulic pressures (30, 60, and 90 MPa) using an indirect squeeze casting process. Thermal histories throughout the die wall and the casting surface have been recorded by fine type-K thermocouples. The in-cavity local pressures measured by pressure transducers were explored at the casting-die interfaces of 5 steps. The casting-die interfacial heat transfer coefficients (IHTC) initially reached a maximum peak value followed by a gradually decline to the lower level. Similar characteristics of IHTC peak values can be observed at the applied pressures of 30, 60 and 90 MPa. With the applied pressure of 90 MPa, the peak IHTC values from steps 1 to 5 varied from 5623 to 10,649 W/m2 K. As the applied hydraulic pressure increased, the IHTC peak value of each step was increased accordingly. The wall thickness also affected IHTC peak values significantly. The peak IHTC value and heat flux increased as the step became thicker. The empirical equations relating the IHTCs to the local pressures and the solidification temperature at the casting surface were developed based on the multivariate linear and polynomial regression.

  1. An attached flow design of a noninterfering leading edge extension to a thick delta wing

    NASA Technical Reports Server (NTRS)

    Ghaffari, F.; Lamar, J. E.

    1985-01-01

    The analytical procedure presented for leading edge extension (LEE) determination, in keeping with such design criteria as noninterference at the wing design point, is applied to thick delta wings. The LEE device thus defined is to be mounted on a wing along a dividing stream surface that is associated with an attached flow design lift coefficient greater than zero. The delta wing in question is of twisted and cambered type. It is demonstrated that span reductions for the candidate LEEs has the most detrimental effect on overall aerodynamic efficiency, irrespective of area or shape.

  2. Improved design of special boundary elements for T-shaped reinforced concrete walls

    NASA Astrophysics Data System (ADS)

    Ji, Xiaodong; Liu, Dan; Qian, Jiaru

    2017-01-01

    This study examines the design provisions of the Chinese GB 50011-2010 code for seismic design of buildings for the special boundary elements of T-shaped reinforced concrete walls and proposes an improved design method. Comparison of the design provisions of the GB 50011-2010 code and those of the American code ACI 318-14 indicates a possible deficiency in the T-shaped wall design provisions in GB 50011-2010. A case study of a typical T-shaped wall designed in accordance with GB 50011-2010 also indicates the insufficient extent of the boundary element at the non-flange end and overly conservative design of the flange end boundary element. Improved designs for special boundary elements of T-shaped walls are developed using a displacement-based method. The proposed design formulas produce a longer boundary element at the non-flange end and a shorter boundary element at the flange end, relative to those of the GB 50011-2010 provisions. Extensive numerical analysis indicates that T-shaped walls designed using the proposed formulas develop inelastic drift of 0.01 for both cases of the flange in compression and in tension.

  3. First wall and blanket module safety enhancement by material selection and design decision

    SciTech Connect

    Merrill, B.J.

    1980-01-01

    A thermal/mechanical study has been performed which illustrates the behavior of a fusion reactor first wall and blanket module during a loss of coolant flow event. The relative safety advantages of various material and design options were determined. A generalized first wall-blanket concept was developed to provide the flexibility to vary the structural material (stainless steel vs titanium), coolant (helium vs water), and breeder material (liquid lithium vs solid lithium aluminate). In addition, independent vs common first wall-blanket cooling and coupled adjacent module cooling design options were included in the study. The comparative analyses were performed using a modified thermal analysis code to handle phase change problems.

  4. Design, fabrication, and testing of duralumin zoom mirror with variable thickness

    NASA Astrophysics Data System (ADS)

    Hui, Zhao; Xie, Xiaopeng; Xu, Liang; Ding, Jiaoteng; Shen, Le; Liu, Meiying; Gong, Jie

    2016-10-01

    Zoom mirror is a kind of active optical component that can change its curvature radius dynamically. Normally, zoom mirror is used to correct the defocus and spherical aberration caused by thermal lens effect to improve the beam quality of high power solid-state laser since that component was invented. Recently, the probable application of zoom mirror in realizing non-moving element optical zoom imaging in visible band has been paid much attention. With the help of optical leveraging effect, the slightly changed local optical power caused by curvature variation of zoom mirror could be amplified to generate a great alteration of system focal length without moving elements involved in, but in this application the shorter working wavelength and higher surface figure accuracy requirement make the design and fabrication of such a zoom mirror more difficult. Therefore, the key to realize non-moving element optical zoom imaging in visible band lies in zoom mirror which could provide a large enough saggitus variation while still maintaining a high enough surface figure. Although the annular force based actuation could deform a super-thin mirror having a constant thickness to generate curvature variation, it is quite difficult to maintain a high enough surface figure accuracy and this phenomenon becomes even worse when the diameter and the radius-thickness ratio become bigger. In this manuscript, by combing the pressurization based actuation with a variable thickness mirror design, the purpose of obtaining large saggitus variation and maintaining quite good surface figure accuracy at the same time could be achieved. A prototype zoom mirror with diameter of 120mm and central thickness of 8mm is designed, fabricated and tested. Experimental results demonstrate that the zoom mirror having an initial surface figure accuracy superior to 1/50λ could provide at least 21um saggitus variation and after finishing the curvature variation its surface figure accuracy could still be

  5. Modeling Enclosure Design in Above-Grade Walls

    SciTech Connect

    Lstiburek, J.; Ueno, K.; Musunuru, S.

    2016-03-01

    This report describes the modeling of typical wall assemblies that have performed well historically in various climate zones. The WUFI (Warme und Feuchte instationar) software (Version 5.3) model was used. A library of input data and results are provided. The provided information can be generalized for application to a broad population of houses, within the limits of existing experience. The WUFI software model was calibrated or tuned using wall assemblies with historically successful performance. The primary performance criteria or failure criteria establishing historic performance was moisture content of the exterior sheathing. The primary tuning parameters (simulation inputs) were airflow and specifying appropriate material properties. Rational hygric loads were established based on experience - specifically rain wetting and interior moisture (RH levels). The tuning parameters were limited or bounded by published data or experience. The WUFI templates provided with this report supply useful information resources to new or less-experienced users. The files present various custom settings that will help avoid results that will require overly conservative enclosure assemblies. Overall, better material data, consistent initial assumptions, and consistent inputs among practitioners will improve the quality of WUFI modeling, and improve the level of sophistication in the field.

  6. Development of a Versatile Laser-Ultrasonic System and Application to the Online Measurement for Process Control of Wall Thickness and Eccentricity of Seamless Tubes

    SciTech Connect

    Robert V. Kolarik II

    2002-10-23

    A system for the online, non-contact measurement of wall thickness in steel seamless mechanical tubing has been developed and demonstrated at a tubing production line at the Timken Company in Canton, Ohio. The system utilizes laser-generation of ultrasound and laser-detection of time of flight with interferometry, laser-doppler velocimetry and pyrometry, all with fiber coupling. Accuracy (<1% error) and precision (1.5%) are at targeted levels. Cost and energy savings have exceeded estimates. The system has shown good reliability in measuring over 200,000 tubes in its first six months of deployment.

  7. Thick Co-Deposits and Dust in Controlled Fusion Devices with Carbon Walls: Fuel Inventory and Growth Rate of Co-Deposited Layers

    NASA Astrophysics Data System (ADS)

    Rubel, M.; Philipps, V.; Tanabe, T.; Wienhold, P.; Freisinger, M.; Linke, J.; von Seggern, J.; Wessel, E.

    Recent results regarding the formation of co-deposits, fuel accumulation and overall material transport at the TEXTOR tokamak are described. Two categories of brittle flaking co-deposits were identified: (i) smooth stratified layers of a thickness of up to 50 mm and a fuel content of up to 16 at.% , (ii) granular and columnar structures reaching 1 mm in thickness and con-taining around 0.5 at.% of fuel species. They were formed on the blades of the toroidal belt pump limiter (˜15000 s of plasma operation) and on the neutral-iser plates of this limiter (˜90000 s), respectively. A comparison is made to the fuel inventory measured in other controlled fusion devices with carbon walls.

  8. Thick airfoil designs for the root of the 10MW INNWIND.EU wind turbine

    NASA Astrophysics Data System (ADS)

    Mu≁oz, A.; Méndez, B.; Munduate, X.

    2016-09-01

    The main objective of the “INNWIND.EU” project is to investigate and demonstrate innovative designs for 10-20MW offshore wind turbines and their key components, such as lightweight rotors. In this context, the present paper describes the development of two new airfoils for the blade root region. From the structural point of view, the root is the region in charge of transmitting all the loads of the blade to the hub. Thus, it is very important to include airfoils with adequate structural properties in this region. The present article makes use of high-thickness and blunt trailing edge airfoils to improve the structural characteristics of the airfoils used to build this blade region. CENER's (National Renewable Energy Center of Spain) airfoil design tool uses the airfoil software XFOIL to compute the aerodynamic characteristics of the designed airfoils. That software is based on panel methods which show some problems with the calculation of airfoils with thickness bigger than 35% and with blunt trailing edge. This drawback has been overcome with the development of an empirical correction for XFOIL lift and drag prediction based on airfoil experiments. From the aerodynamic point of view, thick airfoils are known to be very sensitive to surface contamination or turbulent inflow conditions. Consequently, the design optimization takes into account the aerodynamic torque in both clean and contaminated conditions. Two airfoils have been designed aiming to improve the structural and the aerodynamic behaviour of the blade in clean and contaminated conditions. This improvement has been corroborated with Blade Element Momentum (BEM) computations.

  9. Designing and adjusting the thickness of polyvinylpyrrolidone waveguide layer on plasmonic nanofilm for humidity sensing

    NASA Astrophysics Data System (ADS)

    Feng, Zhiqing; Bai, Lan; Guo, Lijiao; Cao, Baosheng; Wu, Jinlei; He, Yangyang

    2017-01-01

    We developed a fast response and high-resolution plasmonic waveguide sensor for sensing environmental humidity by converting the optical signal in the visible light region. The sensor was designed as a layer-on-layer film structure in which the hydrophilic polymer of polyvinylpyrrolidone (PVP) film served as the waveguide layer and was dip-coated onto the plasmonic gold (Au) nanofilm for sensing the environmental humidity. The amount of the absorbed water molecules on the PVP layer could affect the refractive index and thickness of the PVP, leading to a shift of the surface plasmon resonance peak position of Au nanofilm at the different order modes of the waveguide. The theoretic calculations indicated that the optimal thickness of the waveguide layer on the Au nanofilm ranged from 550 to 650 nm. By adjusting the thickness of the PVP layer to 560 nm, the high-resolution optical signals were observed in the visible light region with the humidity shifts ranging from 11% to 85% relative humidity (RH). Our work details a successful attempt to design and prepare the plasmonic waveguide sensor with the lost-cost polymer as the sensing layer for real-time detection of environmental humidity.

  10. Analysis of transient heat flow to thick-walled plates and cylinders. [to determine gas heat transfer coefficient

    NASA Technical Reports Server (NTRS)

    Powell, W. B.

    1973-01-01

    A methodology is described for the analysis of a transient temperature measurement made in a flat or curved plate subjected to convective heat transfer, such that the surface heat flux, the hot-gas temperture, and the gas heat transfer coefficient can be determined. It is shown that if the transient temperature measurement is made at a particular point located nearly midway in the thickness of the plate there is an important simplification in the data analysis process, in that the factor relating the surface heat flux to the measured rate of rise of temperature becomes invariant for a Fourier Number above 0.60 and for all values of the Biot Number. Parameters are derived, tabulated, and plotted which enable straightforward determination of the surface heat flux, the hot-gas temperature, of the plate, the rate of rise of temperature, the plate thickness and curvature, and the mean thermal properties of the plate material at the test temperature.

  11. An analytical design procedure for the determination of effective leading edge extensions on thick delta wings

    NASA Technical Reports Server (NTRS)

    Ghaffari, F.; Chaturvedi, S. K.

    1984-01-01

    An analytical design procedure for leading edge extensions (LEE) was developed for thick delta wings. This LEE device is designed to be mounted to a wing along the pseudo-stagnation stream surface associated with the attached flow design lift coefficient of greater than zero. The intended purpose of this device is to improve the aerodynamic performance of high subsonic and low supersonic aircraft at incidences above that of attached flow design lift coefficient, by using a vortex system emanating along the leading edges of the device. The low pressure associated with these vortices would act on the LEE upper surface and the forward facing area at the wing leading edges, providing an additional lift and effective leading edge thrust recovery. The first application of this technique was to a thick, round edged, twisted and cambered wing of approximately triangular planform having a sweep of 58 deg and aspect ratio of 2.30. The panel aerodynamics and vortex lattice method with suction analogy computer codes were employed to determine the pseudo-stagnation stream surface and an optimized LEE planform shape.

  12. DYNA3D Finite Element Analysis of Steam Explosion Loads on a Pedestal Wall Design

    SciTech Connect

    Noble, C R

    2007-01-18

    The objective of this brief report is to document the ESBWR pedestal wall finite element analyses that were performed as a quick turnaround effort in July 2005 at Lawrence Livermore National Laboratory and describe the assumptions and failure criteria used for these analyses [Ref 4]. The analyses described within are for the pedestal wall design that included an internal steel liner. The goal of the finite element analyses was to assist in determining the load carrying capacity of the ESBWR pedestal wall subjected to an impulsive pressure generated by a steam explosion.

  13. Ordered hexagonal mesoporous aluminosilicates synthesized using zeolite as precursor and the wall-thickness tuned by pH control

    NASA Astrophysics Data System (ADS)

    Wang, Chunlei; Zhu, Guangshang; Shang, Tiecun; Cai, Xiaohui; Liu, Chengzhan; Li, Nan; Wei, Yuhong; Li, Jian; Zhang, Weiwei; Qiu, Shilun

    2005-07-01

    High aluminium content mesoporous aluminosilicates MAS-X1 and MAS-X3 have been successfully synthesized using zeolite FAU-X as precursors and triblock copolymer pluronic P123 as structure directing agent. Samples have been characterized by XRD, TEM, nitrogen adsorption/desorption, 27Al MAS NMR, and ICP element analysis techniques. The salt, NaCl, which was introduced by dissolving the zeolite FAU-X, played an important role in the synthesis of high order sample. The secondary growth of the wall was considered to occur after the pH value had been increased up to five.

  14. Increased Infarct Wall Thickness by a Bio-Inert Material Is Insufficient to Prevent Negative Left Ventricular Remodeling after Myocardial Infarction

    PubMed Central

    Rane, Aboli A.; Chuang, Joyce S.; Shah, Amul; Hu, Diane P.; Dalton, Nancy D.; Gu, Yusu; Peterson, Kirk L.; Omens, Jeffrey H.; Christman, Karen L.

    2011-01-01

    Background Several injectable materials have been shown to preserve or improve cardiac function as well as prevent or slow left ventricular (LV) remodeling post-myocardial infarction (MI). However, it is unclear as to whether it is the structural support or the bioactivity of these polymers that lead to beneficial effects. Herein, we examine how passive structural enhancement of the LV wall by an increase in wall thickness affects cardiac function post-MI using a bio-inert, non-degradable synthetic polymer in an effort to better understand the mechanisms by which injectable materials affect LV remodeling. Methods and Results Poly(ethylene glycol) (PEG) gels of storage modulus G′ = 0.5±0.1 kPa were injected and polymerized in situ one week after total occlusion of the left coronary artery in female Sprague Dawley rats. The animals were imaged using magnetic resonance imaging (MRI) at 7±1 day(s) post-MI as a baseline and again post-injection 49±4 days after MI. Infarct wall thickness was statistically increased in PEG gel injected vs. control animals (p<0.01). However, animals in the polymer and control groups showed decreases in cardiac function in terms of end diastolic volume, end systolic volume and ejection fraction compared to baseline (p<0.01). The cellular response to injection was also similar in both groups. Conclusion The results of this study demonstrate that passive structural reinforcement alone was insufficient to prevent post-MI remodeling, suggesting that bioactivity and/or cell infiltration due to degradation of injectable materials are likely playing a key role in the preservation of cardiac function, thus providing a deeper understanding of the influencing properties of biomaterials necessary to prevent post-MI negative remodeling. PMID:21731777

  15. Direct measurement of wall slip and slip layer thickness of non-Brownian hard-sphere suspensions in rectangular channel flows

    NASA Astrophysics Data System (ADS)

    Jesinghausen, Steffen; Weiffen, Rene; Schmid, Hans-Joachim

    2016-09-01

    Wall slip is a long-known phenomenon in the field of rheology. Nevertheless, the origin and the evolution are not completely clear yet. Regarding suspensions, the effect becomes even more complicated, because different mechanisms like pure slip or slip due to particle migration have to be taken into account. Furthermore, suspensions themselves show many flow anomalies and the isolation of slip is complicated. In order to develop working physical models, further insight is necessary. In this work, we measured experimentally the wall slip velocities of different highly filled suspensions in a rectangular slit die directly with respect to the particle concentration and the particle size. The slip velocities were obtained using a particle image velocimetry (PIV) system. The suspensions consisting of a castor oil-cinnamon oil blend and PMMA particles were matched in terms of refractive indexes to appear transparent. Hereby, possible optical path lengths larger than 15 mm were achieved. The slip velocities were found to be in a quadratic relation to the wall shear stress. Furthermore, the overall flow rate as well as the particle concentration has a direct influence on the slip. Concerning the shear stress, there seem to be two regions of slip with different physical characteristics. Furthermore, we estimated the slip layer thickness directly from the velocity profiles and propose a new interpretation. The PIV technique is used to investigate the viscosity and implicit the concentration profile in the slit die. It is shown that the particle migration process is quite fast.

  16. Analysis of thermal residual stress in a thick-walled ring of Duralcan-base Al-SiC functionally graded material

    SciTech Connect

    Fukui, Yasuyoshi; Watanabe, Yoshimi

    1996-12-01

    A ring-cutting test and an elastic theory were applied to evaluate the macroscopic residual stress in a thick-walled ring made of Al-SiC functionally graded material (FGM). The FGM ring specimens, with outer diameter 90 mm, radial thickness approximately 8.4 to 10 mm, and width 30 mm, were fabricated by the centrifugal casting method from an ingot of Duralcan F3D.20S of Al-20 vol pct SiC master composite. Because of a difference in centrifugal forces of SiC particles and of molten aluminum alloy, the rings had a graded composition of SiC particles in the radial direction. The volume fractions of SiC particles in each ring specimen varied in the range of 0 to 43 vol pct from the inner to the outer surface of the ring, depending on the applied mold spin speed. A ring diametral compression test was performed to validate an analytical formula based on the curved beam theory that can account for the graded properties of the material. Excellent agreement between the theory that can account for the graded properties of the material. Excellent agreement between the theory and the experiment was found. The residual stress was found to be generated by a cooling of {Delta}T = 140 K, which was from half the melting point corresponding stress-free condition to the ambient temperature. The hoop residual stresses in the FGM ring varied in the range of {minus}50 to +35 MPa and from tension at the inner surface to compression at the outer space because of the graded composition. With an increase in wall thickness and/or composition gradation, the residual stresses were found to increase.

  17. A correlation of thin lens approximation to thick lens design by using context based method in optics education

    NASA Astrophysics Data System (ADS)

    Farsakoglu, O. F.; Inal Atik, Ipek; Kocabas, Hikmet

    2014-07-01

    The effect of Coddington factors on aberration functions has been analysed using thin lens approximation with optical glass parameters. The dependence of spherical aberration on Coddington shape factor for the various optical glasses in real lens design was discussed using exact ray tracing for the optics education and training purposes. Thin lens approximation and thick lens design are generally taught with only lecturing method. But, thick lens design is closely related to the real life. Hence, it is more appropriate to teach thin lens approximation and thick lens design with real-life context based approach. Context based teaching can be effective in solving problems in which the subject is very difficult and irrelevant. It also provides extensive evidence for optics education that students are generally unable to correctly apply the concepts of lens design to optical instruments currently used. Therefore, the outline of real-life context based thick lens design lessons were proposed and explained in detail considering thin lens approximation.

  18. Using the Front Page of "The Wall Street Journal" to Teach Document Design and Audience Analysis.

    ERIC Educational Resources Information Center

    Moore, Patrick

    1989-01-01

    Explains an assignment for the audience analysis segment of a business writing course which compares the front page design of "The Wall Street Journal" with that of a local daily newspaper in order to emphasize the use of design devices in effectively writing to busy people. (SR)

  19. Using the Front Page of "The Wall Street Journal" to Teach Document Design and Audience Analysis.

    ERIC Educational Resources Information Center

    Moore, Patrick

    1989-01-01

    Explains an assignment for the audience analysis segment of a business writing course which compares the front page design of "The Wall Street Journal" with that of a local daily newspaper in order to emphasize the use of design devices in effectively writing to busy people. (SR)

  20. An Attached Flow Design of a Noninterferring Leading Edge Extension to a Thick Delta Wing

    NASA Technical Reports Server (NTRS)

    Lamar, John E.; Ghaffari, Farhad

    1985-01-01

    An analytical procedure for the determination of the shape of a Leading-Edge Extension (LEE) which satisfies design criteria, including especially noninterference at the wing design point, has been developed for thick delta wings. The LEE device best satisfying all criteria is designed to be mounted on a wing along a dividing stream surface associated with an attached flow design lift coefficient (C(sub L,d)) of greater than zero. This device is intended to improve the aerodynamic performance of transonic aircraft at C(sub L) greater than C(sub L,d) system emanating from the LEE leading edge. In order to quantify this process a twisted and cambered thick delta wing was chosen for the initial application of this design procedure. Appropriate computer codes representing potential and vortex flows were employed to determine the dividing stream surface at C(sub L,d) and an optimized LEE planform shape at C(sub L) greater than C(sub L,d), respectively. To aid in the LEE selection, the aerodynamic effectiveness of 36 planforms was investigated at C(sub L) greater than C(sub L,d). This study showed that reducing the span of the candidate LEEs has the most detrimental effect on overall aerodynamic efficiency, regardless of the shape or area. Furthermore, for a fixed area, constant-chord LEE candidates were relatively more efficient than those with sweep less than the wing. At C(sub L,d), the presence of the LEE planform best satisfying the design criteria was found to have no effect on the wing alone aerodynamic performance.

  1. Breaking Down Walls to Creativity through Interdisciplinary Design

    ERIC Educational Resources Information Center

    West, Richard E.

    2016-01-01

    This article describes initial success in developing an interdisciplinary studio for teaching collaborative creativity and design, with faculty from multiple departments co-teaching and co-mentoring interdisciplinary student groups engaged in social innovation. The rationale for developing this studio has been to prepare students for the kind of…

  2. Breaking Down Walls to Creativity through Interdisciplinary Design

    ERIC Educational Resources Information Center

    West, Richard E.

    2016-01-01

    This article describes initial success in developing an interdisciplinary studio for teaching collaborative creativity and design, with faculty from multiple departments co-teaching and co-mentoring interdisciplinary student groups engaged in social innovation. The rationale for developing this studio has been to prepare students for the kind of…

  3. Individuals, grasses, and forests of single- and multi-walled carbon nanotubes grown by supported Co catalysts of different nominal thicknesses

    NASA Astrophysics Data System (ADS)

    Kakehi, Kazunori; Noda, Suguru; Maruyama, Shigeo; Yamaguchi, Yukio

    2008-08-01

    The relationships among the nominal thickness of Co catalyst, the structure of the catalyst particles, and the structure of carbon nanotubes (CNTs) growing from the catalyst during chemical vapor deposition were investigated. Various morphologies of CNTs such as individuals, random networks parallel to the surface of the substrate ('grasses'), and vertically aligned forests of single- and multi-walled carbon nanotubes were grown by only varying the nominal thickness of catalyst under the same reaction condition. These different morphologies at the same growth time were due to the different areal density rather than to the length of CNTs. With increasing nominal thickness of catalyst, the catalyst particles changed in diameter while their areal density remained relatively almost constant. The change in diameter possibly affected the number ratio of active catalyst particles to the whole particles, which in turn affected the areal density of CNTs and yielded the various morphologies. Longer growth time increased the CNT length, which caused further change in CNT morphologies from individuals to grasses and grasses to forests.

  4. Integrated analysis and design of thick composite structures for optimal passive damping characteristics

    NASA Technical Reports Server (NTRS)

    Saravanos, D. A.

    1993-01-01

    The development of novel composite mechanics for the analysis of damping in composite laminates and structures and the more significant results of this effort are summarized. Laminate mechanics based on piecewise continuous in-plane displacement fields are described that can represent both intralaminar stresses and interlaminar shear stresses and the associated effects on the stiffness and damping characteristics of a composite laminate. Among other features, the mechanics can accurately model the static and damped dynamic response of either thin or thick composite laminates, as well as, specialty laminates with embedded compliant damping layers. The discrete laminate damping theory is further incorporated into structural analysis methods. In this context, an exact semi-analytical method for the simulation of the damped dynamic response of composite plates was developed. A finite element based method and a specialty four-node plate element were also developed for the analysis of composite structures of variable shape and boundary conditions. Numerous evaluations and applications demonstrate the quality and superiority of the mechanics in predicting the damped dynamic characteristics of composite structures. Finally, additional development was focused on the development of optimal tailoring methods for the design of thick composite structures based on the developed analytical capability. Applications on composite plates illustrated the influence of composite mechanics in the optimal design of composites and the potential for significant deviations in the resultant designs when more simplified (classical) laminate theories are used.

  5. A thick multilayer thermal barrier coating: Design, deposition, and internal stresses

    NASA Astrophysics Data System (ADS)

    Samadi, Hamed

    Yttria Partially Stabilized Zirconia (Y-PSZ) plasma-sprayed coatings are widely used in turbine engines as thermal barrier coatings. However, in diesel engines Y-PSZ TBCs have not met with wide success. To reach the desirable temperature of 850-900°C in the combustion chamber from the current temperature of 400-600°C, a coating with a thickness of approximately 1mm is required. This introduces different considerations than in the case of turbine blade coatings, which are on the order of 100mum thick. Of the many factors affecting the durability and failure mechanism of TBCs, in service and residual stresses play an especially important role as the thickness of the coating increases. For decreasing the residual stress in the system, a multi-layer coating is helpful. The design of a multilayer coating employing relatively low cost materials with complementary thermal properties is described. Numerical models were used to describe the residual stress after deposition and under operating conditions for a multilayer coating that exhibited the desired temperature gradient. Results showed that the multilayer coating had a lower maximum stress under service conditions than a conventional Y-PSZ coating. Model validation with experiments showed a good match between the two.

  6. Low-speed aerodynamic characteristics of a 13-percent-thick airfoil section designed for general aviation applications

    NASA Technical Reports Server (NTRS)

    Mcghee, R. J.; Beasley, W. D.; Somers, D. M.

    1975-01-01

    Wind-tunnel tests were conducted to determine the low-speed section characteristics of a 13 percent-thick airfoil designed for general aviation applications. The results were compared with NACA 12 percent-thick sections and with the 17 percent-thick NASA airfoil. The tests were conducted ovar a Mach number range from 0.10 to 0.35. Chord Reynolds numbers varied from about 2,000,000 to 9,000,000.

  7. National Transonic Facility Wall Pressure Calibration Using Modern Design of Experiments (Invited)

    NASA Technical Reports Server (NTRS)

    Underwood, Pamela J.; Everhart, Joel L.; DeLoach, Richard

    2001-01-01

    The Modern Design of Experiments (MDOE) has been applied to wind tunnel testing at NASA Langley Research Center for several years. At Langley, MDOE has proven to be a useful and robust approach to aerodynamic testing that yields significant reductions in the cost and duration of experiments while still providing for the highest quality research results. This paper extends its application to include empty tunnel wall pressure calibrations. These calibrations are performed in support of wall interference corrections. This paper will present the experimental objectives, and the theoretical design process. To validate the tunnel-empty-calibration experiment design, preliminary response surface models calculated from previously acquired data are also presented. Finally, lessons learned and future wall interference applications of MDOE are discussed.

  8. Functional plant cell wall design revealed by the Raman imaging approach.

    PubMed

    Richter, Stephan; Müssig, Jörg; Gierlinger, Notburga

    2011-04-01

    Using the Raman imaging approach, the optimization of the plant cell wall design was investigated on the micron level within different tissue types at different positions of a Phormium tenax leaf. Pectin and lignin distribution were visualized and the cellulose microfibril angle (MFA) of the cell walls was determined. A detailed analysis of the Raman spectra extracted from the selected regions, allowed a semi-quantitative comparison of the chemical composition of the investigated tissue types on the micron level. The cell corners of the parenchyma revealed almost pure pectin and the cell wall an amount of 38-49% thereof. Slight lignification was observed in the parenchyma and collenchyma in the top of the leaf and a high variability (7-44%) in the sclerenchyma. In the cell corners and in the cell wall of the sclerenchymatic fibres surrounding the vascular tissue, the highest lignification was observed, which can act as a barrier and protection of the vascular tissue. In the sclerenchyma high variable MFA (4°-40°) was detected, which was related with lignin variability. In the primary cell walls a constant high MFA (57°-58°) was found together with pectin. The different plant cell wall designs on the tissue and microlevel involve changes in chemical composition as well as cellulose microfibril alignment and are discussed and related according to the development and function.

  9. A Fusion Reactor Design with a Liquid First Wall and Divertor

    SciTech Connect

    Nygren, R E; Rognlien, T D; Rensink, M E; Smolentsev, S S; Youssef, M E; Sawan, M Z; Merrill, B J; Eberle, C; Fogarty, P J; Nelson, B E; Sze, D K; Majeski, R

    2003-11-13

    Within the magnetic fusion energy program in the US, a program called APEX is investigating the use of free flowing liquid surfaces to form the inner surface of the chamber around the plasma. As part of this work, the APEX Team has investigated several possible design implementations and developed a specific engineering concept for a fusion reactor with liquid walls. Our approach has been to utilize an already established design for a future fusion reactor, the ARIES-RS, for the basic chamber geometry and magnetic configuration and to replace the chamber technology in this design with liquid wall technology for a first wall and divertor and a blanket with adequate tritium breeding. This paper gives an overview of one design with a molten salt (a mixture of lithium, beryllium and sodium fluorides) forming the liquid surfaces and a ferritic steel for the structural material of the blanket. The design point is a reactor with 3840MW of fusion power of which 767MW is in the form of energetic particles (alpha power) and 3073MW is in the form of neutrons. The alpha plus auxiliary power total 909MW of which 430MW is radiated from the core mostly onto the first wall and the balance flows into the edge plasma and is distributed between the first wall and the divertor. In pursuing the application of liquid surfaces in APEX, the team has developed analytical tools that are significant achievements themselves and also pursued experiments on flowing liquids. This work is covered elsewhere, but the paper will also note several such areas to indicate the supporting science behind the design presented. Significant new work in modeling the plasma edge to understand the interaction of the plasma with the liquid walls is one example. Another is the incorporation of magneto-hydrodynamic (MHD) effects in fluid modeling and heat transfer.

  10. Left ventricular wall stress compendium.

    PubMed

    Zhong, L; Ghista, D N; Tan, R S

    2012-01-01

    Left ventricular (LV) wall stress has intrigued scientists and cardiologists since the time of Lame and Laplace in 1800s. The left ventricle is an intriguing organ structure, whose intrinsic design enables it to fill and contract. The development of wall stress is intriguing to cardiologists and biomedical engineers. The role of left ventricle wall stress in cardiac perfusion and pumping as well as in cardiac pathophysiology is a relatively unexplored phenomenon. But even for us to assess this role, we first need accurate determination of in vivo wall stress. However, at this point, 150 years after Lame estimated left ventricle wall stress using the elasticity theory, we are still in the exploratory stage of (i) developing left ventricle models that properly represent left ventricle anatomy and physiology and (ii) obtaining data on left ventricle dynamics. In this paper, we are responding to the need for a comprehensive survey of left ventricle wall stress models, their mechanics, stress computation and results. We have provided herein a compendium of major type of wall stress models: thin-wall models based on the Laplace law, thick-wall shell models, elasticity theory model, thick-wall large deformation models and finite element models. We have compared the mean stress values of these models as well as the variation of stress across the wall. All of the thin-wall and thick-wall shell models are based on idealised ellipsoidal and spherical geometries. However, the elasticity model's shape can vary through the cycle, to simulate the more ellipsoidal shape of the left ventricle in the systolic phase. The finite element models have more representative geometries, but are generally based on animal data, which limits their medical relevance. This paper can enable readers to obtain a comprehensive perspective of left ventricle wall stress models, of how to employ them to determine wall stresses, and be cognizant of the assumptions involved in the use of specific models.

  11. Design guidelines for advanced LSI microcircuit packaging using thick film multilayer technology

    NASA Technical Reports Server (NTRS)

    Peckinpaugh, C. J.

    1974-01-01

    Ceramic multilayer circuitry results from the sequential build-up of two or more layers of pre-determined conductive interconnections separated by dielectric layers and fired at an elevated temperature to form a solidly fused structure. The resultant ceramic interconnect matrix is used as a base to mount active and passive devices and provide the necessary electrical interconnection to accomplish the desired electrical circuit. Many methods are known for developing multilevel conductor mechanisms such as multilayer printed circuits, welded wire matrices, flexible copper tape conductors, and thin and thick-film ceramic multilayers. Each method can be considered as a specialized field with each possessing its own particular set of benefits and problems. This design guide restricts itself to the art of design, fabrication and assembly of ceramic multilayer circuitry and the reliability of the end product.

  12. Steam-assisted crystallization of TPA{sup +}-exchanged MCM-41 type mesoporous materials with thick pore walls

    SciTech Connect

    Chen, Hong Li; Zhang, Kun; Wang, Yi Meng

    2012-07-15

    Highlights: ► Mesoporous Ti-containing silica with thicker pore walls was synthesized. ► Ion-exchange and steam-assisted crystallization led to MCM-41/MFI composite. ► The introduction of Ti inhibited the formation of separated MFI particles. ► Lower temperature favored retaining mesoporous characteristics and morphology. -- Abstract: Hierarchical MCM-41/MFI composites were synthesized through ion-exchange of as-made MCM-41 type mesoporous materials with tetrapropylammonium bromide and subsequent steam-assisted recrystallization. The obtained samples were characterized by powder X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis, FT-IR, {sup 1}H–{sup 13}C CP/MAS and nitrogen adsorption–desorption. The XRD patterns show that the MCM-41/MFI composite possesses both ordered MCM-41 phase and zeolite MFI phase. SEM and TEM images indicate that the recrystallized materials retained the mesoporous characteristics and the morphology of as-made mesoporous materials without the formation of bulky zeolite, quite different from the mechanical mixture of MCM-41 and MFI structured zeolite. Among others, lower recrystallization temperature and the introduction of the titanium to the parent materials are beneficial to preserve the mesoporous structure during the recrystallization process.

  13. Experimental study of ASCs combined with POC-PLA patch for the reconstruction of full-thickness chest wall defects.

    PubMed

    Zhang, Yuanzheng; Fang, Shuo; Dai, Jiezhi; Zhu, Lei; Fan, Hao; Tang, Weiya; Fan, Yongjie; Dai, Haiying; Zhang, Peipei; Wang, Ying; Xing, Xin; Yang, Chao

    2017-01-01

    To explore the repairing effect of combination of adipose stem cells (ASCs) and composite scaffolds on CWR, the electrospun Poly 1, 8-octanediol-co-citric acid (POC)-poly-L-lactide acid (PLA) composite scaffolds were prepared, followed by in vitro and in vivo biocompatibility evaluation of the scaffolds. Afterwards, ASCs were seeded on POC-PLA to construct the POC-PLA-ASCs scaffolds, and the POC-PLA, POC-PLA-ASCs, and traditional materials expanded polytetrafluoroethylene (ePTFE) were adopt for CWR in New Zealand white (NZW) rabbit models. As results, the POC-PLA-ASCs patches possessed good biocompatibility as the high proliferation ability of cells surrounding the patches. Rabbits in POC-PLA-ASCs groups showed better pulmonary function, less pleural adhesion, higher degradation rate and more neovascularization when compared with that in other two groups. The results of western blot indicated that POC-PLA-ASCs patches accelerated the expression of VEGF and Collagen I in rabbit models. From the above, our present study demonstrated that POC-PLA material was applied for CWR successfully, and ASCs seeded on the sheets could improve the pleural adhesions and promote the reparation of chest wall defects.

  14. A thick-walled sphere rotating in a uniform magnetic field: The next step to de-spin a space object

    NASA Astrophysics Data System (ADS)

    Nurge, Mark A.; Youngquist, Robert C.; Caracciolo, Ryan A.; Peck, Mason; Leve, Frederick A.

    2017-08-01

    Modeling the interaction between a moving conductor and a static magnetic field is critical to understanding the operation of induction motors, eddy current braking, and the dynamics of satellites moving through Earth's magnetic field. Here, we develop the case of a thick-walled sphere rotating in a uniform magnetic field, which is the simplest, non-trivial, magneto-statics problem that leads to complete closed-form expressions for the resulting potentials, fields, and currents. This solution requires knowledge of all of Maxwell's time independent equations, scalar and vector potential equations, and the Lorentz force law. The paper presents four cases and their associated experimental results, making this topic appropriate for an advanced student lab project.

  15. Space station integrated wall design and penetration damage control

    NASA Technical Reports Server (NTRS)

    Coronado, A. R.; Gibbins, M. N.; Wright, M. A.; Stern, P. H.

    1987-01-01

    The analysis code BUMPER executes a numerical solution to the problem of calculating the probability of no penetration (PNP) of a spacecraft subject to man-made orbital debris or meteoroid impact. The codes were developed on a DEC VAX 11/780 computer that uses the Virtual Memory System (VMS) operating system, which is written in FORTRAN 77 with no VAX extensions. To help illustrate the steps involved, a single sample analysis is performed. The example used is the space station reference configuration. The finite element model (FEM) of this configuration is relatively complex but demonstrates many BUMPER features. The computer tools and guidelines are described for constructing a FEM for the space station under consideration. The methods used to analyze the sensitivity of PNP to variations in design, are described. Ways are suggested for developing contour plots of the sensitivity study data. Additional BUMPER analysis examples are provided, including FEMs, command inputs, and data outputs. The mathematical theory used as the basis for the code is described, and illustrates the data flow within the analysis.

  16. Automated airway evaluation system for multi-slice computed tomography using airway lumen diameter, airway wall thickness and broncho-arterial ratio

    NASA Astrophysics Data System (ADS)

    Odry, Benjamin L.; Kiraly, Atilla P.; Novak, Carol L.; Naidich, David P.; Lerallut, Jean-Francois

    2006-03-01

    Pulmonary diseases such as bronchiectasis, asthma, and emphysema are characterized by abnormalities in airway dimensions. Multi-slice computed tomography (MSCT) has become one of the primary means to depict these abnormalities, as the availability of high-resolution near-isotropic data makes it possible to evaluate airways at oblique angles to the scanner plane. However, currently, clinical evaluation of airways is typically limited to subjective visual inspection only: systematic evaluation of the airways to take advantage of high-resolution data has not proved practical without automation. We present an automated method to quantitatively evaluate airway lumen diameter, wall thickness and broncho-arterial ratios. In addition, our method provides 3D visualization of these values, graphically illustrating the location and extent of disease. Our algorithm begins by automatic airway segmentation to extract paths to the distal airways, and to create a map of airway diameters. Normally, airway diameters decrease as paths progress distally; failure to taper indicates abnormal dilatation. Our approach monitors airway lumen diameters along each airway path in order to detect abnormal profiles, allowing even subtle degrees of pathologic dilatation to be identified. Our method also systematically computes the broncho-arterial ratio at every terminal branch of the tree model, as a ratio above 1 indicates potentially abnormal bronchial dilatation. Finally, the airway wall thickness is computed at corresponding locations. These measurements are used to highlight abnormal branches for closer inspection, and can be summed to compute a quantitative global score for the entire airway tree, allowing reproducible longitudinal assessment of disease severity. Preliminary tests on patients diagnosed with bronchiectasis demonstrated rapid identification of lack of tapering, which also was confirmed by corresponding demonstration of elevated broncho-arterial ratios.

  17. A new multichannel time reversal focusing method for circumferential Lamb waves and its applications for defect detection in thick-walled pipe with large-diameter.

    PubMed

    Liu, Zenghua; Xu, Qinglong; Gong, Yu; He, Cunfu; Wu, Bin

    2014-09-01

    This paper proposes a new multichannel time reversal focusing (MTRF) method for circumferential Lamb waves which is based on modified time reversal algorithm and applies this method for detecting different kinds of defects in thick-walled pipe with large-diameter. The principle of time reversal of circumferential Lamb waves in pipe is presented along with the influence from multiple guided wave modes and propagation paths. Experimental study is carried out in a thick-walled and large-diameter pipe with three artificial defects, namely two axial notches on its inner and outer surface respectively, and a corrosion-like defect on its outer surface. By using the proposed MTRF method, the multichannel signals focus at the defects, leading to the amplitude improvement of the defect scattered signal. Besides, another energy focus arises in the direct signal due to the partial compensation of dispersion and multimode of circumferential Lamb waves, alongside the multichannel focusing, during MTRF process. By taking the direct focus as a time base, accurate defect localization is implemented. Secondly, a new phenomenon is exhibited in this paper that defect scattered wave packet appears just before the right boundary of truncation window after time reversal, and to which two feasible explanations are given. Moreover, this phenomenon can be used as the theoretical basis in the determination of defect scattered waves in time reversal response signal. At last, in order to detect defects without prior knowing their exact position, a large-range truncation window is used in the proposed method. As a result, the experimental operation of MTRF method is simplified and defect detection and localization are well accomplished. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. AlGaAs ridge laser with 33% wall-plug efficiency at 100 °C based on a design of experiments approach

    NASA Astrophysics Data System (ADS)

    Fecioru, Alin; Boohan, Niall; Justice, John; Gocalinska, Agnieszka; Pelucchi, Emanuele; Gubbins, Mark A.; Mooney, Marcus B.; Corbett, Brian

    2016-04-01

    Upcoming applications for semiconductor lasers present limited thermal dissipation routes demanding the highest efficiency devices at high operating temperatures. This paper reports on a comprehensive design of experiment optimisation for the epitaxial layer structure of AlGaAs based 840 nm lasers for operation at high temperature (100 °C) using Technology Computer-Aided Design software. The waveguide thickness, Al content, doping level, and quantum well thickness were optimised. The resultant design was grown and the fabricated ridge waveguides were optimised for carrier injection and, at 100 °C, the lasers achieve a total power output of 28 mW at a current of 50 mA, a total slope efficiency 0.82 W A-1 with a corresponding wall-plug efficiency of 33%.

  19. Low-alloy steels for thick-walled pressure vessels. Summary report, February 1, 1980-January 31, 1982

    SciTech Connect

    Todd, J.A.; Chung, D.W.; Parker, E.R.

    1982-01-01

    This program aimed to modify existing commercial pressure vessel steels to provide strong, tough, creep resistant materials, with low hydrogen attack and temper embrittlement susceptibilities, which can also be field-fabricated into thick-section vessels for coal conversion systems. Emphasis was placed on determining the effects of Mn, Ni and Cr on the creep rupture and hydrogen attack susceptibilities of Cr-Mo steels. Hydrogen attack studies were also carried out on A533B and model alloy systems to investigate the role of alloy carbides in promoting resistance to hydrogen damage. Creep rupture fracture times were determined at 500, 560 and 600/sup 0/C for periods up to 2000 hours. The effects of cooling rate from the austenitizing temperature and tempering response on the microstructure of 3Cr-1Mo-1Mn-1Ni steel were studied. The carbide structures in all the alloy modifications were carefully characterized. Data were collected from preliminary weld bead-on-plate tests of A387 and temper embrittlement studies of A543 with mischmetal addition. The unloading compliance test technique for J/sub Ic/ measurements was completed for A533B specimens but shortage of material prevented testing of A387. The mechanical property, elevated temperature creep and hydrogen attack data suggested that addition of 0.75 Cr + 0.5 Mn + 1Ni was beneficial in reducing susceptibility to hydrogen damage but was detrimental to creep rupture properties. 44 figures, 14 tables.

  20. Novel synthesis of thick wall coatings of titania supported Bi poisoned Pd catalysts and application in selective hydrogenation of acetylene alcohols in capillary microreactors.

    PubMed

    Cherkasov, Nikolay; Ibhadon, Alex O; Rebrov, Evgeny V

    2015-04-21

    Catalysis in microreactors allows reactions to be performed in a very small volume, reducing the environmental problems and greatly intensifying the processes through easy pressure control and the elimination of heat- and mass-transfer limitations. In this study, we report a novel method for the controlled synthesis of micrometre-thick mesoporous TiO2 catalytic coatings on the walls of long channels (>1 m) of capillary microreactors in a single deposition step. The method uses elevated temperature and introduces a convenient control parameter of the deposition rate (displacement speed controlled by a stepper motor), which allows deposition from concentrated and viscous sols without channel clogging. A capillary microreactor wall-coated with titania supported Bi-poisoned Pd catalyst was obtained using the method and used for the semihydrogenation of 2-methyl-3-butyn-2-ol providing 93 ± 1.5% alkene yield for 100 h without deactivation. Although the coating method was applied only for TiO2 deposition, it is nonetheless suitable for the deposition of volatile sols.

  1. Femtosecond laser assisted design of sutureless intrastromal graft as an alternative to partial thickness keratoplasty

    NASA Astrophysics Data System (ADS)

    Rossi, Francesca; Durkee, Heather; Pini, Roberto; Canovetti, Annalisa; Malandrini, Alex; Lenzetti, Ivo; Rubino, Pierangela; Leaci, Rosachiara; Neri, Alberto; Scaroni, Patrizia; Menabuoni, Luca; Macaluso, Claudio

    2014-02-01

    Minimally invasive laser assisted surgery in ophthalmology is continuously developing in order to find new surgical approaches, preserve patient tissue and improve surgical results in terms of cut precision, restoration of visual acuity, and invasiveness. In order to achieve these goals, the current approach in corneal transplant is lamellar keratoplasty, where only the anterior or posterior part of the patient's cornea is substituted depending on the lesion or pathology. In this work, we present a novel alternative approach: a case study of intrastromal sutureless transplant, where a portion of the anterior stroma of a donor cornea was inserted into the stroma of the recipient cornea, aiming to restore the correct thickness of the patient's cornea. The patient cornea was paracentrally thin, as the result of a trophic ulcer due to ocular pemphigoid. A discoid corneal graft from the anterior stroma of a donor eye was prepared: a femtosecond laser cut with a trapezoidal profile (thickness was 300 μm, minor and major basis were 3.00 and 3.50 mm, respectively). In the recipient eye, an intrastromal cut was also performed with the femtosecond laser using a specifically designed mask; the cut position was 275 μm in depth. The graft was loaded into an injector and inserted as an intrastromal presbyopic implant. The postoperative analysis evidenced a clear and stable graft that selectively restored corneal thickness in the thinned area. Intrastromal corneal transplant surgery is a minimally invasive alternative to anterior or posterior lamellar keratoplasty in select cases. We believe that Sutureless Intrastromal Laser Keratoplasty (SILK) could open up new avenues in the field of corneal transplantation by fully utilizing the potential and precision of existing lasers.

  2. Differences in near-wall shear rate in the carotid artery within subjects are associated with different intima-media thicknesses.

    PubMed

    Kornet, L; Lambregts, J; Hoeks, A P; Reneman, R S

    1998-12-01

    In the common carotid artery, reflections originating from the periphery and the flow divider may affect the shape of the flow velocity profile and, hence, near-wall shear rate (WSR) differently just before the bifurcation (location B) than 20 to 30 mm farther upstream (location A). Recent developments in ultrasound technology allow the assessment of WSR and intima-media thickness (IMT) at the same site in the carotid artery in vivo. We therefore determined WSR at locations A and B and investigated whether the differences between both sites, if any, were associated with different IMTs and different mechanical properties of the arterial wall. The effect of age on the possible differences was assessed as well. The study was performed on presumably healthy volunteers (n=53). In all individuals, IMT was larger at location B than at location A. The relative difference in IMT between both locations was not affected by age. No significant differences in diameter and distension were found between locations. Near peak systolic and near mean WSR at the posterior wall (PWSRp and MWSRp, respectively) were significantly lower at location B than at location A. The relative differences in PWSRp and MWSRp between both locations within subjects were independent of age. The velocity profiles were more blunted at location A than at location B. PWSRp and MWSRp significantly decreased and IMT significantly increased with age at both locations. IMT was negatively correlated with PWSRP and MWSRP at location B, but this correlation was not significant at location A. In summary, in the common carotid artery, the lower WSR near the bifurcation, as compared with 20 to 30 mm upstream, is associated with a larger IMT than at the more proximal site. The relative difference between both locations within subjects is independent of age.

  3. Design of multi-level thick seam extractions under major aquifiers and considering spontaneous combustion risk

    SciTech Connect

    Reddish, D.J.; Dunham, R.K.

    1996-12-01

    The paper presents an approach to design a multi level room and pillar layout in a 40m thick seam overlain by a major aquifer. The design was required to maximize extraction with due consideration of the general stability of the workings, the potential water hazards, and spontaneous combustion risks due to air leakage between horizons. The approach utilized was a combination of empirical pillar sizing for water hazard control with numerical modelling to assess potential interactions between horizons. The numerical modelling allowed the size of interleaves, and the appropriate staggers to be optimized in terms of stress distribution. The stress distribution allows both the general stability of the openings and more importantly the permeability changes around the openings to be determined. The permeability of coal is sensitive to stress, and an empirical stress to permeability relationship, and theoretical permeability to flow leakage relationship has been applied to interpreting the relative spontaneous combustion risk associated with each of the proposed layouts. The final proposed design is a compromise between maximum exploitation of reserves and consideration of water hazards and of spontaneous combustion risk. Further more detailed design will be required as more comprehensive data on the geotechnical properties of the coal and overburden become available.

  4. Development of automated welding process for field fabrication of thick walled pressure vessels. Fourth quarter, FY 1980

    SciTech Connect

    Not Available

    1980-12-19

    Progress is reported in research on the automated welding of heavy steel plate for the fabrication of pressure vessels. Information is included on: torch and shield adaptation; mechanical control of the welding process; welding parameters; joint design; filler wire optimizaton; nondestructive testing of welds; and weld repair. (LCL)

  5. Computer-aided orbital wall defects treatment by individual design ultrahigh molecular weight polyethylene implants.

    PubMed

    Kozakiewicz, Marcin

    2014-06-01

    Despite of well-known advantages of high molecular weight polyethylene (Medpor, Synpore) in orbital reconstructions, the thickness of those implants significantly exceeds 0.5 mm and precise modification of thickness is limited. The aim of this study was to present the application of a self-developed method of treatment orbital wall fracture by custom implant made of ultrahigh molecular weight polyethylene (UHMW-PE). First, the test of influence of sterilization process upon implant deformation was performed (autoclaving, ethylene oxide, gas plasma, irradiation). Next, ten cases for delayed surgical treatment of orbital fracture were included into this study (7 males, 3 females). Based on CT scan and mirrored technique, a CAD model of virtual implant for repairing orbital wall was made. Then, an implant was manufactured with a computer numerical controlled milling machine from UHMW-PE block, sterilized and used during a surgical procedure. Clinically used implants had thickness from 0.2 to 4.0 mm. The best method of sterilization is ethylene oxide process, and the worst is autoclaving. In this series of delayed surgical cases, functional results of orbital surgery are worse than in simpler, early treated cases, but long-term subsidence of diplopia is noticeable [10% poor results]. The results of the treatment depend on the initial level of diplopia where severe initial diplopia to be corrected requires thicker implants (p < 0.01). It also leads to longer surgical procedures (p < 0.01), but prolongation of the surgery had no negative influence upon results of any investigated follow-up examinations. Obviously, the orbital destruction intensity is related to injury-evoked initial diplopia but it also influences whole results of treatment up to 12 months post-op. Interesting result is presented by the relation of maximal implant thickness to 12-month diplopia evaluation. Thicker implants used result in lower residual diplopia (p < 0.05). This is important because of

  6. Conceptual design of divertor and first wall for DEMO-FNS

    NASA Astrophysics Data System (ADS)

    Sergeev, V. Yu.; Kuteev, B. V.; Bykov, A. S.; Gervash, A. A.; Glazunov, D. A.; Goncharov, P. R.; Dnestrovskij, A. Yu.; Khayrutdinov, R. R.; Klishchenko, A. V.; Lukash, V. E.; Mazul, I. V.; Molchanov, P. A.; Petrov, V. S.; Rozhansky, V. A.; Shpanskiy, Yu. S.; Sivak, A. B.; Skokov, V. G.; Spitsyn, A. V.

    2015-11-01

    Key issues of design of the divertor and the first wall of DEMO-FNS are presented. A double null closed magnetic configuration was chosen with long external legs and V-shaped corners. The divertor employs a cassette design similar to that of ITER. Water-cooled first wall of the tokamak is made of Be tiles and CuCrZr-stainless steel shells. Lithium injection and circulation technologies are foreseen for protection of plasma facing components. Simulations of thermal loads onto the first wall and divertor plates suggest a possibility to distribute heat loads making them less than 10 MW m-2. Evaluations of sputtering and evaporation of plasma-facing materials suggest that lithium may protect the first wall. To prevent Be erosion at the outer divertor plates either the full detached divertor operation or arrangement of the renewal lithium flow on targets should be implemented. Test bed experiments on the Tsefey-M facility with the first wall mockup coated by Ве tiles and cooled by water are presented. The temperature of the surface of tiles reached 280-300 °С at 5 MW m-2 and 600-650 °С at 10.5 MW m-2. The mockup successfully withstood 1000 cycles with the lower thermal loading and 100 cycles with higher thermal loading.

  7. Non-uniform thickness in Europa's icy shell: implications for astrobiology mission design

    NASA Astrophysics Data System (ADS)

    Fairén, A.; Amils, R.

    The exploration of Europa's subsurface ocean is hardly constrained by the presence of an outer ice shell of unknown thickness: a somewhat thin crust would allow easier access to the ocean below. Current estimates for the thickness of Europa's icy surface range from a few km [1] to a few tens of km [2], the shell overlying a liquid water ocean up to 150 km thick [3,4,5]. The surface is believed to be young (mean age of 30-80 Myr [6]) and geologically active [7,8,9], as it is sparsely cratered. Here we report geological evidence indicating that the thickness of Europa's ice crust is actually a complex combination of thicker and thinner areas, highlighting the implications of such structure in the future exploration of the inner ocean. Detailed geologic mapping of impact craters, palimpsests and chaotic terrains distribution on Europa's surface, offers an initial approach to a comprehensive description of the thickness variation in the ice shell. Our analysis is based in: (1) Crater distribution, morphology, diameter and depth. Seminal work by Schenk [2] of transitions in crater shape/diameter suggested enhanced structural collapse of craters with diameter >27-33 km, that will consequently form multiring basins, due to weaker ice or a global ocean at depths >19-25 km. This being true, strictly can only be interpreted regionally: multiring basins indicate regions where the ice shell is thick; in those regions where the icy surface is thin, a bolide impact will breach the ice and leave neither crater nor multiring basin behind, but probably Ganymede's type palimpsests. (2) Palimpsest-type features distribution, indicating regions where the ice shell is too thin to support crater formation after big bolide impacts. In Ganymede, palimpsests are circular, low albedo and relief features formerly formed by impacts [10,11]. (3) Chaotic terrain distribution, considering features tens to hundreds of km across, that may be the evidence for very thin ice areas (from ˜ 2 km to

  8. Design of Highly Photofunctional Porous Polymer Films with Controlled Thickness and Prominent Microporosity

    PubMed Central

    Gu, Cheng; Huang, Ning; Wu, Yang; Xu, Hong; Jiang, Donglin

    2015-01-01

    Porous organic polymers allow the integration of various π-units into robust porous π-networks, but they are usually synthesized as unprocessable solids with poor light-emitting performance as a result of aggregation-related excitation dissipation. Herein, we report a general strategy for the synthesis of highly emissive photofunctional porous polymer films on the basis of a complementary scheme for the structural design of aggregation-induced-emissive π-systems. We developed a high-throughput and facile method for the direct synthesis of large-area porous thin films at the liquid–electrode interface. The approach enables the preparation of microporous films within only a few seconds or minutes and allows precise control over their thickness with sub-nanometer precision. By virtue of rapid photoinduced electron transfer, the thin films can detect explosives with enhanced sensitivity to low parts-per-million levels in a selective manner. PMID:26234636

  9. Low speed aerodynamic characteristics of a 17 percent thick airfoil section designed for general aviation applications

    NASA Technical Reports Server (NTRS)

    Mcghee, R. J.; Beasley, W. D.

    1973-01-01

    Wind-tunnel tests have been conducted to determine the low-speed two-dimensional aerodynamic characteristics of a 17-percent-thick airfoil designed for general aviation applications (GA(W)-1). The results were compared with predictions based on a theoretical method for calculating the viscous flow about the airfoil. The tests were conducted over a Mach number range from 0.10 to 0.28. Reynolds numbers based on airfoil chord varied from 2.0 million to 20.0 million. Maximum section lift coefficients greater than 2.0 were obtained and section lift-drag ratio at a lift coefficient of 1.0 (climb condition) varied from about 65 to 85 as the Reynolds number increased from about 2.0 million to 6.0 million.

  10. Re-design and fabrication of titanium multi-wall Thermal Protection System (TPS) test panels

    NASA Technical Reports Server (NTRS)

    Blair, W.; Meaney, J. E., Jr.; Rosenthal, H. A.

    1984-01-01

    The Titanium Multi-wall Thermal Protection System (TIPS) panel was re-designed to incorporate Ti-6-2-4-2 outer sheets for the hot surface, ninety degree side closures for ease of construction and through panel fastness for ease of panel removal. Thermal and structural tests were performed to verify the design. Twenty-five panels were fabricated and delivered to NASA for evaluation at Langley Research Center and Johnson Space Center.

  11. Design and function of an electron mobility spectrometer with a thick gas electron multiplier

    NASA Astrophysics Data System (ADS)

    Orchard, Gloria M.; Puddu, Silvia; Waker, Anthony J.

    2016-04-01

    The design and function of an electron mobility spectrometer (EMS) including a thick gas electron multiplier (THGEM) is presented. The THGEM was designed to easily be incorporated in an existing EMS to investigate the ability to detect tritium in air using a micropattern gas detector. The THGEM and a collection plate (anode) were installed and the appropriate circuitry was designed and connected to supply the required voltages to the THGEM-EMS. An alpha source (241Am) was used to generate electron-ion pairs within the gas-filled sensitive volume of the EMS. The electrons were used to investigate the THGEM-EMS response as a function of applied voltage to the THGEM and anode. The relative gas-gain and system resolution of the THGEM-EMS were measured at various applied voltage settings. It was observed a potential difference across the THGEM of +420 V and potential difference across the induction region of +150 V for this EMS setup resulted in the minimum voltage requirements to operate with a stable gain and system resolution. Furthermore, as expected, the gain is strongly affected not only by the potential difference across the THGEM, but also by the applied voltage to the anode and resulting potential difference between the THGEM and anode.

  12. Design, fabrication, and testing of contact-aided compliant cellular mechanisms with curved walls

    NASA Astrophysics Data System (ADS)

    Cirone, Samantha A.; Hayes, Gregory R.; Babcox, Brian L.; Frecker, Mary; Adair, James H.; Lesieutre, George A.

    2011-03-01

    Contact-Aided Compliant Cellular Mechanisms (C3M) are compliant cellular structures with integrated contact mechanisms. The focus of the paper is on the design, fabrication, and testing of C3M with curved walls for high strain applications. It is shown that global strains were increased by replacing straight walls with curved walls in the traditional honeycomb structure, while the addition of contact mechanisms increased cell performance via stress relief in some cases. Furthermore, curved walls are beneficial for fabrication at the meso-scale. The basic curved honeycomb cell geometry is defined by a set of variables. These variables were optimized using Matlab and finite element analysis to find the best non-contact and contact-aided curved cell geometries as well as the cell geometry that provides the greatest stress relief. Currently, the most effective contact-aided curved honeycomb cell can withstand global strains approximately 160% greater than the most effective contact-aided, non-curved cell. Four different designs were fabricated via the Lost Mold-Rapid Infiltration Forming (LM-RIF) process. An array of the contact-aided optimized curved cell was then mechanically tested using a custom designed test rig, and the results were found to have a higher modulus of elasticity and lower global strain than the predictions. Despite these discrepancies, a high-strength highstrain cellular structure was developed, for potential use in morphing aircraft applications.

  13. The Growing Outer Epidermal Wall: Design and Physiological Role of a Composite Structure

    PubMed Central

    Kutschera, U.

    2008-01-01

    Background The cells of growing plant organs secrete an extracellular fibrous composite (the primary wall) that allows the turgid protoplasts to expand irreversibly via wall-yielding events, which are regulated by processes within the cytoplasm. The role of the epidermis in the control of stem elongation is described with special reference to the outer epidermal wall (OEW), which forms a ‘tensile skin’. Novel Facts The OEW is much thicker and less extensible than the walls of the inner tissues. Moreover, in the OEW the amount of cellulose per unit wall mass is considerably greater than in the inner tissues. Ultrastructural studies have shown that the expanding OEW is composed of a highly ordered internal and a diffuse outer half, with helicoidally organized cellulose microfibrils in the inner (load-bearing) region of this tension-stressed organ wall. The structural and mechanical backbone of the wall consists of helicoids, i.e. layers of parallel, inextensible cellulose microfibrils. These ‘plywood laminates’ contain crystalline ‘cables’ orientated in all directions with respect to the axis of elongation (isotropic material). Cessation of cell elongation is accompanied by a loss of order, i.e. the OEW is a dynamic structure. Helicoidally arranged extracellular polymers have also been found in certain bacteria, algae, fungi and animals. In the insect cuticle crystalline cutin nanofibrils form characteristic ‘OEW-like’ herringbone patterns. Conclusions Theoretical considerations, in vitro studies and computer simulations suggest that extracellular biological helicoids form by directed self-assembly of the crystalline biopolymers. This spontaneous generation of complex design ‘without an intelligent designer’ evolved independently in the protective ‘skin’ of plants, animals and many other organisms. PMID:18258808

  14. Correlation of left ventricular wall thickness, heart mass, serological parameters and late gadolinium enhancement in cardiovascular magnetic resonance imaging of myocardial inflammation in an experimental animal model of autoimmune myocarditis.

    PubMed

    Kromen, Wolfgang; Korkusuz, Huedayi; Korkusuz, Yuecel; Esters, Philip; Bauer, Ralf W; Huebner, Frank; Lindemayr, Sebastian; Vogl, Thomas J

    2012-12-01

    For a definitive diagnosis of myocarditis, different strategies like analysis of late gadolinium enhancement (LGE) in cardiovascular magnetic resonance imaging (CMR) up to invasive endomyocardial biopsy have been applied. The objective of the study was to investigate inflammatory changes like left ventricular wall thickening and increase of ventricular mass and to quantitatively analyse their correlation with extent and localisation of myocardial damage in CMR and with subsequent changes of serological markers in an animal model of an experimental autoimmune myocarditis (EAM). In the current study, an EAM was induced in 10 male Lewis rats, 10 rats served as control. On day 21, animals were examined with four CMR protocols to assess the extent of LGE in a 12 segment model of the rat heart. Left myocardial wall thickness and mass and histological grade of inflammation were measured to determine localisation and severity of the induced myocarditis. Depending on the CMR sequence, LGE was mostly found in the left anterior (9.6%) and left lateral (8.7%) myocardial wall segments. Wall thickness correlated with the LGE area in CMR imaging and the histopathological severity of myocarditis for the left lateral myocardial wall segment. In a similar way, the heart mass correlated to the extent of LGE for the left lateral segment. We conclude that in our animal model left ventricular wall thickness and mass reflect the severity of myocardial changes in myocarditis and that the EAM rat model is well suited for further investigations of myocarditis.

  15. Design of two-dimensional channels with prescribed velocity distributions along the channel walls

    NASA Technical Reports Server (NTRS)

    Stanitz, John D

    1953-01-01

    A general method of design is developed for two-dimensional unbranched channels with prescribed velocities as a function of arc length along the channel walls. The method is developed for both compressible and incompressible, irrotational, nonviscous flow and applies to the design of elbows, diffusers, nozzles, and so forth. In part I solutions are obtained by relaxation methods; in part II solutions are obtained by a Green's function. Five numerical examples are given in part I including three elbow designs with the same prescribed velocity as a function of arc length along the channel walls but with incompressible, linearized compressible, and compressible flow. One numerical example is presented in part II for an accelerating elbow with linearized compressible flow, and the time required for the solution by a Green's function in part II was considerably less than the time required for the same solution by relaxation methods in part I.

  16. Influence of preparation design on fit and ceramic thickness of CEREC 3 partial ceramic crowns after cementation.

    PubMed

    Kim, Jae-Hoon; Cho, Byeong-Hoon; Lee, Jin-Hee; Kwon, Soo-Jung; Yi, Young-Ah; Shin, Yooseok; Roh, Byoung-Duck; Seo, Deog-Gyu

    2015-02-01

    This study investigated the influence of preparation design on the marginal and internal gap and ceramic thickness of partial ceramic crowns (PCCs) fabricated with the CEREC 3 system. Sixteen extracted human mandibular molars were prepared according to two different preparation designs (n = 8): a retentive preparation design with traditional cusp capping (Group I) and a non-retentive preparation design with horizontal reduction of cusps (Group II). PCCs were fabricated from IPS Empress CAD with the CEREC 3 system. The parameters for luting space and minimum occlusal ceramic thickness were set to 30 μm and 1.5 mm, respectively. The fabricated PCCs were cemented to their corresponding teeth with self-adhesive resin cement and were then scanned by micro-computed tomography. The marginal and internal gaps were measured at pre-determined measuring points in five bucco-lingual and three mesio-distal cross-sectional images. The ceramic thicknesses of the PCCs were measured at the measuring points for cusp capping areas. Group II (167.4 ± 76.4 μm) had a smaller overall mean gap, which included the marginal and internal gap measurements, than that of Group I (184.8 ± 89.0 μm). The internal gaps were larger than the marginal gaps, regardless of preparation design. Group I presented a thinner ceramic thickness in the cusp capping areas than the minimum occlusal ceramic thickness parameter of 1.5 mm. CONCLUSION. Preparation design had an influence on fit, particularly the internal gap of the PCCs. Ceramic thickness could be thinner than the minimum ceramic thickness parameter.

  17. Spacecraft wall design for increased protection against penetration by space debris impacts

    NASA Technical Reports Server (NTRS)

    Schonberg, William P.; Tullos, Randy J.

    1990-01-01

    All orbiting spacecraft are susceptible to impacts by meteoroids and pieces of orbital space debris. These impacts occur at extremely high speeds and can damage flight-critical systems, which can in turn lead to catastrophic failure of the spacecraft. The design of a spacecraft for a long-duration mission into the meteoroid and space debris environment must include adequate protection against perforation of pressurized components by such impacts. This paper presents the results of an investigation into the perforation resistance of dual-wall structural systems fabricated with monolithic bumper plates and with corrugated bumper plates of equal weight. A comparative analysis of the impact damage in dual-wall systems with corrugated bumper specimens and that in dual-wall specimens with monolithic bumpers of similar weight is performed to determine the advantages and disadvantages of employing corrugated bumpers in structural wall systems for long-duration spacecraft. The analysis indicates that a significant increase in perforation protection can be achieved if a monolithic bumper is replaced by a corrugated bumper of equal weight. The parameters of the corrugations in the corrugated bumper plates are optimized in a manner that minimizes the potential for the creation of ricochet debris in the event of an oblique hypervelocity impact. Several design examples using the optimization scheme are presented and discussed.

  18. Effects of cardiac resynchronization therapy on left ventricular mass and wall thickness in mild heart failure patients in MADIT-CRT.

    PubMed

    Kutyifa, Valentina; Solomon, Scott D; Bourgoun, Mikhail; Shah, Amil M; Pouleur, Anne-Catherine; Knappe, Dorit; McNitt, Scott; Wang, Paul J; Merkely, Bela; Pfeffer, Marc; Moss, Arthur J; Zareba, Wojciech

    2013-03-01

    The effect of cardiac resynchronization therapy (CRT) on left ventricular wall thickness and left ventricular mass (LVM) is unknown. To evaluate the effects of CRT on septal and posterior wall thickness (SWT and PWT) and LVM in patients with left bundle branch block (LBBB) and non-LBBB vs implantable cardioverter-defibrillator patients and to assess the relationship between CRT-induced changes and cardiac events. We investigated 843 patients with LBBB and 366 patients with non-LBBB enrolled in the Multicenter Automatic Defibrillator Implantation Trial - Cardiac Resynchronization Therapy (MADIT-CRT) trial to analyze changes in SWT, PWT, and LVM at 12 months and subsequent outcome. The primary end point was heart failure or death; secondary end points included ventricular tachycardia, ventricular fibrillation, or death. In LBBB patients, reduction in SWT, PWT, and LVM was more pronounced in CRT defibrillator (CRT-D) than in implantable cardioverter-defibrillator (SWT:-6.7% ± 4.4% vs-1.0% ± 1.9%; PWT:-6.4% ± 4.3% vs-0.8% ± 1.9%; LVM:-23.6% ± 9.9% vs-5.1% ± 5.1%; P<.001 for all). In CRT-D patients with non-LBBB, LVM reduction was less pronounced; however, changes in SWT and PWT were comparable. Changes in LVM correlated with changes in left ventricular end-diastolic volume. In CRT-D patients with LBBB, reduction in SWT and LVM was associated with reduction in heart failure/death (SWT: hazard ratio 0.94; 95% confidence interval 0.89-0.99 per percent change; P = .03) and ventricular tachycardia/ventricular fibrillation/death (SWT: hazard ratio 0.95; 95% confidence interval 0.91-1.00; P = .04). CRT-D patients with non-LBBB did not show favorable reduction in clinical or arrhythmic end points related to changes in SWT, PWT, or LVM. CRT-D was associated with significant reduction in SWT, PWT, and LVM in patients with LBBB along with left ventricular volume changes and associated favorable clinical and arrhythmia outcomes. Published by Elsevier Inc.

  19. Right ventricular relative wall thickness as a predictor of outcomes and of right ventricular reverse remodeling for patients with pulmonary hypertension.

    PubMed

    Sano, Hiroyuki; Tanaka, Hidekazu; Motoji, Yoshiki; Fukuda, Yuko; Mochizuki, Yasuhide; Hatani, Yutaka; Matsuzoe, Hiroki; Hatazawa, Keiko; Shimoura, Hiroyuki; Ooka, Junichi; Ryo-Koriyama, Keiko; Nakayama, Kazuhiko; Matsumoto, Kensuke; Emoto, Noriaki; Hirata, Ken-Ichi

    2017-03-01

    Mid-term right ventricular (RV) reverse remodeling after treatment in patients with pulmonary hypertension (PH) is associated with long-term outcome as well as baseline RV remodeling. However, baseline factors influencing mid-term RV reverse remodeling after treatment and its prognostic capability remain unclear. We studied 54 PH patients. Mid-term RV remodeling was assessed in terms of the RV area, which was traced planimetrically at the end-systole (RVESA). RV reverse remodeling was defined as a relative decrease in the RVESA of at least 15% at 10.2 ± 9.4 months after treatment. Long-term follow-up was 5 years. Adverse events occurred in ten patients (19%) and mid-term RV reverse remodeling after treatment was observed in 37 (69%). Patients with mid-term RV reverse remodeling had more favorable long-term outcomes than those without (log-rank: p = 0.01). Multivariate logistic regression analysis showed that RV relative wall thickness (RV-RWT), as calculated as RV free-wall thickness/RV basal linear dimension at end-diastole, was an independent predictor of mid-term RV reverse remodeling (OR 1.334; 95% CI, 1.039-1.713; p = 0.03). Moreover, patients with RV-RWT ≥0.21 showed better long-term outcomes than did those without (log-rank p = 0.03), while those with RV-RWT ≥0.21 and mid-term RV reverse remodeling had the best long-term outcomes. Patients with RV-RWT <0.21 and without mid-term RV reverse remodeling, on the other hand, had worse long-term outcomes than other sub-groups. In conclusions, RV-RWT could predict mid-term RV reverse remodeling after treatment in PH patients, and was associated with long-term outcomes. Our finding may have clinical implications for better management of PH patients.

  20. Remote sensing of sea ice thickness by a combined spatial and frequency domain interferometer: formulations, instrument design, and development

    NASA Astrophysics Data System (ADS)

    Hussein, Ziad A.; Holt, Benjamin; McDonald, Kyle C.; Jordan, Rolando; Huang, John; Kuga, Yasuo; Ishimaru, Akira; Jaruwatanadilok, Sermsak; Gogineni, Prasad; Akins, Torry; Heavey, Brandon; Perovich, Don; Sturm, Matthew

    2005-10-01

    The thickness of Arctic sea ice plays a critical role in Earth's climate and ocean circulation. An accurate measurement of this parameter on synoptic scales at regular intervals would enable characterization of this important component for the understanding of ocean circulation and the global heat balance. Presented in this paper is a low frequency VHF interferometer technique and associated radar instrument design to measure sea ice thickness based on the use of backscatter correlation functions. The sea ice medium is represented as a multi-layered medium consisting of snow, sea-ice and sea water, with the interfaces between layers characterized as rough surfaces. This technique utilizes the correlation of two radar waves of different frequencies and incident and observation angles, scattered from the sea ice medium. The correlation functions relate information about the sea ice thickness. Inversion techniques such as the genetic algorithm, gradient descent, and least square methods, are used to derive sea ice thickness from the phase information related by the correlation functions. The radar instrument is designed to be implemented on a spacecraft and the initial test-bed will be on a Twin Otter aircraft. Radar system and instrument design and development parameters as well as some measurement requirements are reviewed. The ability to obtain reliable phase information for successful ice thickness retrieval for various thickness and surface interface geometries is examined.

  1. 3D volume contrast imaging (VCI) for the visualization of placenta previa increta and uterine wall thickness in a dichorionic twin pregnancy.

    PubMed

    Henrich, W; Stupin, J H

    2011-08-01

    Placenta increta is a rare event in pregnancy, but is associated with serious maternal morbidity and mortality due to life threatening hemorrhage. The incidence has increased due to high Cesarean rates. We describe a case of placenta previa increta in a dichorionic twin pregnancy, which was successfully treated conservatively, to discuss the role of ultrasound, especially 3D VCI and TUI, for diagnosis and conservative management in similar cases. A GE Voluson Expert 730 ultrasound system which provides both conventional 2D imaging and 3D volume acquisitions using VCI and TUI was used for diagnosis and management in a case of placenta increta in a dichorionic twin pregnancy in which the placenta previa increta of the first fetus was left in situ and the other placenta was removed. The 3D VCI provided superior resolution of the anterior wall of the uterus, delineating the myometrial thickness in the area of the placental implantation site. With superior image quality, the 3D VCI technique facilitates the evaluation of the myometrial thickness and the depth of placental invasion due to significantly improved enhancement of the contrast and differentiation between various tissues compared to the 2D scan. We describe for the first time the application of 3D VCI and TUI for the visualization of the depth of placental invasion in such a case. Preoperative ultrasound diagnosis allows appropriate preoperative preparations and the decision to leave the placenta untouched to avoid a probable fatal outcome for the patient. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Dynamics of thin-walled aerospace structures for fixture design in multi-axis milling

    NASA Astrophysics Data System (ADS)

    Meshreki, Mouhab

    Milling of thin-walled aerospace structures is a critical process due to the high flexibility of the workpiece. Available models for the prediction of the effect of the fixture on the dynamic response of the workpiece are computationally demanding and fail to represent practical cases for milling of thin-walled structures. Based on the analysis of typical structural components encountered in the aerospace industry, a generalized unit-element, with the shape of an asymmetric pocket, was identified to represent the dynamic response of these components. Accordingly, two computationally efficient dynamic models were developed to predict the dynamic response of typical thin-walled aerospace structures. These models were formulated using Rayleigh's energy and the Rayleigh-Ritz methods. In the first model, the dynamics of multi-pocket thin-walled structures is represented by a plate with torsional and translational springs. A methodology was proposed and implemented for an off-line calibration of the stiffness of the springs using Genetic Algorithms. In the second model, the dynamics of a 3D pocket is represented by an equivalent 2D multi-span plate. Through a careful examination of the milling of thin-walled structures, a new formulation was developed to represent the continuous change of thickness of the workpiece due to the material removal action. Two formulations, based on holonomic constraints and springs with finite stiffness, were also developed and implemented to take into account the effect of perfectly rigid and deformable fixture supports. All the developed models and formulations were validated numerically and experimentally for different workpiece geometries and various types of loading. These models resulted in one to two orders of magnitude reduction in computation time when compared with FE models, with prediction errors of less than 10%. The experimental validation of the models was performed through the machining of thin-walled components. The

  3. New, Virtually Wall-less Cannulas Designed for Augmented Venous Drainage in Minimally Invasive Cardiac Surgery.

    PubMed

    von Segesser, Ludwig Karl; Berdajs, Denis; Abdel-Sayed, Saad; Tozzi, Piergiorgio; Ferrari, Enrico; Maisano, Francesco

    2016-01-01

    Inadequate venous drainage during minimally invasive cardiac surgery becomes most evident when the blood trapped in the pulmonary circulation floods the surgical field. The present study was designed to assess the in vivo performance of new, thinner, virtually wall-less, venous cannulas designed for augmented venous drainage in comparison to traditional thin-wall cannulas. Remote cannulation was realized in 5 bovine experiments (74.0 ± 2.4 kg) with percutaneous venous access over the wire, serial dilation up to 18 F and insertion of either traditional 19 F thin wall, wire-wound cannulas, or through the same access channel, new, thinner, virtually wall-less, braided cannulas designed for augmented venous drainage. A standard minimal extracorporeal circuit set with a centrifugal pump and a hollow fiber membrane oxygenator, but no in-line reservoir was used. One hundred fifty pairs of pump-flow and required pump inlet pressure values were recorded with calibrated pressure transducers and a flowmeter calibrated by a volumetric tank and timer at increasing pump speed from 1500 RPM to 3500 RPM (500-RPM increments). Pump flow accounted for 1.73 ± 0.85 l/min for wall-less versus 1.17 ± 0.45 l/min for thin wall at 1500 RPM, 3.91 ± 0.86 versus 3.23 ± 0.66 at 2500 RPM, 5.82 ± 1.05 versus 4.96 ± 0.81 at 3500 RPM. Pump inlet pressure accounted for 9.6 ± 9.7 mm Hg versus 4.2 ± 18.8 mm Hg for 1500 RPM, -42.4 ± 26.7 versus -123 ± 51.1 at 2500 RPM, and -126.7 ± 55.3 versus -313 ± 116.7 for 3500 RPM. At the well-accepted pump inlet pressure of -80 mm Hg, the new, thinner, virtually wall-less, braided cannulas provide unmatched venous drainage in vivo. Early clinical analyses have confirmed these findings.

  4. Thick methacrylate sections devoid of lost caps simplify stereological quantifications based on the optical fractionator design.

    PubMed

    Hasselholt, Stine; Lykkesfeldt, Jens; Overgaard Larsen, Jytte

    2015-12-01

    In neuroscience, the optical fractionator technique is frequently used for unbiased cell number estimations. Although unbiased in theory, the practical application of the technique is often biased by the necessity of introducing a guard zone at one side of the disector to counter lost caps and/or optical limitations. Restricting the disector within the section thickness potentially introduces bias in two ways. First, the need to measure section thickness in order to obtain the disector height/section thickness fraction is challenging since both microcator measurements, microtome block advance, and measurements on re-embedded sections are potentially biased. Second, disector placement is not uniform random within the section thickness resulting in a bias in most sections with inhomogeneous cell distribution along the z axis. Re-embedded 2-hydroxyethylmethacrylate (hereafter methacrylate) sections were inspected for lost caps to evaluate the possibility of whole section thickness counting with the optical fractionator technique and hippocampal granular cell nucleoli density differences along the z axis were assessed with a z axis analysis. No lost caps were found in the examined re-embedded tissue and an inhomogeneous cell distribution through the section thickness was observed. In thick methacrylate sections devoid of lost caps sampling through the entire section thickness could be an acceptable alternative to the use of guard zones and the consequent biases associated with section thickness measurement and non-random placement of disectors. © 2015 Wiley Periodicals, Inc.

  5. A Fusion Chamber Design with a Liquid First Wall and Divertor

    SciTech Connect

    Nygren, R; Sze, D; Nelson, B; Fogarty, P; Eberle, C; Rognlien, T; Rensink, M; Smolentsev, S; Youssef, M; Sawan, M; Merrill, B; Majeski, R

    2003-11-11

    The APEX study is investigating the use of free flowing liquid surfaces to form the inner surface of the chamber around a fusion plasma. We present a design for the chamber of a 3840MW fusion reactor based on the configuration for the chamber and magnets from ARIESRS but with a fast flowing molten salt of mixed Be, Li and Na fluorides for the first wall and divertor and molten salt blanket with a ferritic steel structure. Our design analysis includes strong radiation from the core and edge plasma, (liquid) MHD effects on the weakly conducting molten salt, a recycling first wall stream that enables a high efficiency thermal conversion, and evaluations of breeding, neutronics, tritium recovery and safety.

  6. Increased serum leptin and resistin levels and increased carotid intima-media wall thickness in patients with psoriasis: is psoriasis associated with atherosclerosis?

    PubMed

    Robati, Reza M; Partovi-Kia, Masoud; Haghighatkhah, Hamid Reza; Younespour, Shima; Abdollahimajd, Fahimeh

    2014-10-01

    Patients with psoriasis may have an increased risk of cardiovascular disease. We sought to evaluate the potential association between subclinical atherosclerosis and psoriasis by measuring the intima-media wall thickness (IMT) of the common carotid artery (CCA) in patients with psoriasis and evaluating its correlation with serum leptin and resistin levels. The mean IMT (MIMT) of the CCA and leptin, resistin, triglyceride (TG), and total cholesterol levels in serum were determined in 60 patients and 60 healthy sex- and age-matched control subjects. Compared with the healthy control subjects, patients with psoriasis had significantly higher MIMT of the CCA and higher levels of serum leptin, resistin, TG, and total cholesterol. In addition, MIMT of the CCA was positively correlated with serum leptin, resistin, TG, and total cholesterol levels in patients with psoriasis. This was a cross-sectional single-center study, and we could not evaluate additional biomarkers such as adipokine or adiponectin because of our restricted facilities. Although serum leptin, resistin, TG, and total cholesterol levels and MIMT of the CCA were significantly increased in patients with psoriasis, MIMT of the CCA was also positively correlated with these biomarkers. Therefore, psoriasis could be an independent risk factor for subclinical atherosclerosis. Copyright © 2014 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  7. Echo features used by human listeners to discriminate among objects that vary in material or wall thickness: implications for echolocating dolphins.

    PubMed

    DeLong, Caroline M; Au, Whitlow W L; Stamper, Sarah A

    2007-01-01

    Echolocating dolphins extract object feature information from the acoustic parameters of echoes. To gain insight into which acoustic parameters are important for object discrimination, human listeners were presented with echoes from objects used in two discrimination tasks performed by dolphins: Hollow cylinders with varying wall thicknesses (+/-0.2, 0.3, 0.4, and 0.8 mm), and spheres made of different materials (steel, aluminum, brass, nylon, and glass). The human listeners performed as well or better than the dolphins at the task of discriminating between the standard object and the comparison objects on both the cylinders (humans=97.1%; dolphin=82.3%) and the spheres (humans= 86.6%; dolphin= 88.7%). The human listeners reported using primarily pitch and duration to discriminate among the cylinders, and pitch and timbre to discriminate among the spheres. Dolphins may use some of the same echo features as the humans to discriminate among objects varying in material or structure. Human listening studies can be used to quickly identify salient combinations of echo features that permit object discrimination, which can then be used to generate hypotheses that can be tested using dolphins as subjects.

  8. Exploring the utility of quantitative network design in evaluating Arctic sea ice thickness sampling strategies

    NASA Astrophysics Data System (ADS)

    Kaminski, T.; Kauker, F.; Eicken, H.; Karcher, M.

    2015-08-01

    We present a quantitative network design (QND) study of the Arctic sea ice-ocean system using a software tool that can evaluate hypothetical observational networks in a variational data assimilation system. For a demonstration, we evaluate two idealised flight transects derived from NASA's Operation IceBridge airborne ice surveys in terms of their potential to improve 10-day to 5-month sea ice forecasts. As target regions for the forecasts we select the Chukchi Sea, an area particularly relevant for maritime traffic and offshore resource exploration, as well as two areas related to the Barnett ice severity index (BSI), a standard measure of shipping conditions along the Alaskan coast that is routinely issued by ice services. Our analysis quantifies the benefits of sampling upstream of the target area and of reducing the sampling uncertainty. We demonstrate how observations of sea ice and snow thickness can constrain ice and snow variables in a target region and quantify the complementarity of combining two flight transects. We further quantify the benefit of improved atmospheric forecasts and a well-calibrated model.

  9. Exploring the utility of quantitative network design in evaluating Arctic sea-ice thickness sampling strategies

    NASA Astrophysics Data System (ADS)

    Kaminski, T.; Kauker, F.; Eicken, H.; Karcher, M.

    2015-03-01

    We present a quantitative network design (QND) study of the Arctic sea ice-ocean system using a software tool that can evaluate hypothetical observational networks in a variational data assimilation system. For a demonstration, we evaluate two idealised flight transects derived from NASA's Operation IceBridge airborne ice surveys in terms of their potential to improve ten-day to five-month sea-ice forecasts. As target regions for the forecasts we select the Chukchi Sea, an area particularly relevant for maritime traffic and offshore resource exploration, as well as two areas related to the Barnett Ice Severity Index (BSI), a standard measure of shipping conditions along the Alaskan coast that is routinely issued by ice services. Our analysis quantifies the benefits of sampling upstream of the target area and of reducing the sampling uncertainty. We demonstrate how observations of sea-ice and snow thickness can constrain ice and snow variables in a target region and quantify the complementarity of combining two flight transects. We further quantify the benefit of improved atmospheric forecasts and a well-calibrated model.

  10. Design and experimental performance of short curved wall diffusers with axial symmetry utilizing slot suction

    NASA Technical Reports Server (NTRS)

    Yang, T.; Hudson, W. G.; Nelson, C. D.

    1973-01-01

    The feasibility of designing short curved wall axially symmetrical subsonic diffusers utilizing suction through slots in the diffuser walls to prevent flow separation was investigated. A potential flow analysis was made, and a digital computer program was written for determining the diffuser wall contour for prescribed boundary conditions. The flow field included branch flow so that the suction slot geometry could be a part of the diffuser design. One bell shaped diffuser and three annular diffusers with area ratios of either 2.5:1 or 3:1 were designed, fabricated, and tested. Minimum suction requirements of metastable operation ranged from 6.3 percent to 12 percent when operating with inlet air velocities in the 1000 to 250 ft/sec (30 to 76 m/sec) range. For stable operation suction rates from 10 percent to 22 percent were required. In all cases the diffuser effectiveness was above 95 percent based on the conventional definition, and from 81 percent to 94 percent when the suction loss was accounted for. The exit velocity profiles were virtually flat with no more than + or - 9% variation over 95 percent of the exit area when operated with sufficient suction to prevent flow separation.

  11. Impact of structural design criteria on first wall surface heat flux limit

    SciTech Connect

    Majumdar, S.

    1998-09-01

    The irradiation environment experienced by the in-vessel components of fusion reactors presents structural design challenges not envisioned in the development of existing structural design criteria such as the ASME Code or RCC-MR. From the standpoint of design criteria, the most significant issues stem from the irradiation-induced changes in material properties, specifically the reduction of ductility, strain hardening capability, and fracture toughness with neutron irradiation. Recently, Draft 7 of the ITER structural design criteria (ISDC), which provide new rules for guarding against such problems, was released for trial use by the ITER designers. The new rules, which were derived from a simple model based on the concept of elastic follow up factor, provide primary and secondary stress limits as functions of uniform elongation and ductility. The implication of these rules on the allowable surface heat flux on typical first walls made of type 316 stainless steel and vanadium alloys are discussed.

  12. [Morphological and functional parameters of the left ventricle (mass, wall thickness and end-systolic stress) in school children with different levels of blood pressure, at rest and during maximal exercise].

    PubMed

    Muñoz, S; Soltero, I; Onorato, E; Pietri, C; Zambrano, F

    1990-01-01

    Echocardiographically determined left ventricular mass, diastolic septal and posterior wall thickness and end-systolic wall stress, as well as electrocardiographic indexes of left ventricular enlargement (Sokolow-Lyon index and Romhilt-Estes score) and of left atrial enlargement (P terminal index) were correlated with resting and exercise systolic and diastolic blood pressures, and with several parameters of body size (weight, height, body surface area, Quetelet index), in 130 school children (61 boys, 69 girls) 6 to 15 years of age. Parameters of body size had a positive correlation both with systolic and diastolic blood pressures and with parameters of left ventricular size. Thus, the latter were adjusted for body surface area, for correlation with blood pressure. Left ventricular mass and diastolic septal and posterior wall thickness had a very poor correlation with resting and exercise diastolic blood pressures. Left ventricular mass and diastolic posterior wall thickness had a significantly higher correlation with peak exercise systolic blood pressure than with resting systolic blood pressure. End-systolic wall stress had a positive correlation with resting diastolic and systolic blood pressures. Electrocardiographic parameters of left ventricular and left atrial enlargement had a very poor correlation with resting and exercise blood pressure. Our findings suggest that early in life left ventricular mass and wall thickness are more closely related to maximal systolic blood pressure during physical exercise than to blood pressure in basal conditions. The electrocardiogram is an insensitive method to detect early modifications of left ventricular size in relation to different levels of blood pressure. The echocardiogram is the method of choice for this purpose.

  13. Optimum design and experimental verification of glue bonding area and thickness for an eight-inch reflective mirror

    NASA Astrophysics Data System (ADS)

    Chan, Chia-Yen; Chen, Yi-Cheng; Huang, Ting-Ming

    2016-09-01

    Effects of glue bonding area and bonding thickness on an eight-inch BOROFLOAT® reflective mirror have been studied numerically and experimentally. The comparison of optical aberrations under the self-weight loading and temperature difference has also been investigated. RTV566 has been selected to bond the mirror with on a ring support mount. The optimum glue bonding area and bonding thickness for isolating the temperature variation have been obtained through a design optimization process and then been used practically. A laser interferometer with a wavelength of 632.8 nm has been used to observe the optical path difference pattern and aberrations. The influence of ambient temperature on the mirror with the optimum glue bonding area and thickness has been carried out. It is concluded that the optimum design of the glue for isolating the temperature variation has been attained numerically and verified successfully with the experimental observations.

  14. Economic analysis of the integrated heating and cooling potential of a residential passive-solar water wall design

    NASA Astrophysics Data System (ADS)

    Roach, F.; Mangeng, C.; Kirschner, C.; Ben-David, S.

    Preliminary performance estimates for the heating and cooling potential of water walls were made. These estimates include the Btu displacement that is attributable to a 300-square foot water wall design in a 1200-square foot residence. The design is for a forced ventalation water wall system that includes the fans and ducting necessary to achieve a 3000-cfm flow of air. The cooling and heating energy displacement estimates are combined with appropriate region-specific fuel prices, system costs, and general economic parameters in a lifecycle cost analysis of this fixed-size water wall design. The economic indicators used to discusse the results include net present value and a total cost goal. Input data and results are presented in mapped form and used to assess the energy savings potential of the water wall in 220 regions of the continental United States.

  15. Multiphysics Engineering Analysis for an Integrated Design of ITER Diagnostic First Wall and Diagnostic Shield Module Design

    SciTech Connect

    Zhai, Y.; Loesser, G.; Smith, M.; Udintsev, V.; Giacomin, T., T.; Khodak, A.; Johnson, D,; Feder, R,

    2015-07-01

    ITER diagnostic first walls (DFWs) and diagnostic shield modules (DSMs) inside the port plugs (PPs) are designed to protect diagnostic instrument and components from a harsh plasma environment and provide structural support while allowing for diagnostic access to the plasma. The design of DFWs and DSMs are driven by 1) plasma radiation and nuclear heating during normal operation 2) electromagnetic loads during plasma events and associate component structural responses. A multi-physics engineering analysis protocol for the design has been established at Princeton Plasma Physics Laboratory and it was used for the design of ITER DFWs and DSMs. The analyses were performed to address challenging design issues based on resultant stresses and deflections of the DFW-DSM-PP assembly for the main load cases. ITER Structural Design Criteria for In-Vessel Components (SDC-IC) required for design by analysis and three major issues driving the mechanical design of ITER DFWs are discussed. The general guidelines for the DSM design have been established as a result of design parametric studies.

  16. Low back injury risks during construction with prefabricated (panelised) walls: effects of task and design factors.

    PubMed

    Kim, Sunwook; Nussbaum, Maury A; Jia, Bochen

    2011-01-01

    New technology designed to increase productivity in residential construction may exacerbate the risk of work-related musculoskeletal disorders (WMSDs) among residential construction workers. Of interest here are panelised (prefabricated) wall systems (or panels) and facilitating an ongoing effort to provide proactive control of ergonomic exposures and risks among workers using panels. This study, which included 24 participants, estimated WMSD risks using five methods during common panel erection tasks and the influences of panel mass (sheathed vs. unsheathed) and size (wall length). WMSD risks were fairly high overall; e.g. 34% and 77% of trials exceeded the 'action limits' for spinal compressive and shear forces, respectively. Heavier (sheathed) panels significantly increased risks, although the magnitude of this effect differed with panel size and between tasks. Higher levels of risk were found in tasks originating from ground vs. knuckle height. Several practical recommendations based on the results are discussed. STATEMENT OF RELEVANCE: Panelised wall systems have the potential to increase productivity in residential construction, but may result in increased worker injury risks. Results from this study can be used to generate future panel design and construction processes that can proactively address WMSD risks.

  17. Designing a Self-Biased CPW Circulator Based on Strontium Hexaferrite Thick Film

    NASA Astrophysics Data System (ADS)

    Kiani, E.; poorbafrani, A.

    2017-08-01

    A 400 μm strontium hexaferrite thick film was prepared through a two-step sintering method; with the grain size diameter of the film about 0.7 μm, the relative density about ρ_{{relative}} = 0.9 , and the remanent magnetization ( M r ) 3940 G. Based on this thick film, a self-biased coplanar waveguide circulator was proposed. The calculated S-parameters indicate that by proper optimization of the structure, an isolation of 19 dB and insertion loss of 1.53 dB is attained. The effects of film porosity and thickness on the insertion losses are discussed.

  18. Optimization of the design of thick, segmented scintillators for megavoltage cone-beam CT using a novel, hybrid modeling technique

    PubMed Central

    Liu, Langechuan; Antonuk, Larry E.; El-Mohri, Youcef; Zhao, Qihua; Jiang, Hao

    2014-01-01

    Purpose: Active matrix flat-panel imagers (AMFPIs) incorporating thick, segmented scintillators have demonstrated order-of-magnitude improvements in detective quantum efficiency (DQE) at radiotherapy energies compared to systems based on conventional phosphor screens. Such improved DQE values facilitate megavoltage cone-beam CT (MV CBCT) imaging at clinically practical doses. However, the MV CBCT performance of such AMFPIs is highly dependent on the design parameters of the scintillators. In this paper, optimization of the design of segmented scintillators was explored using a hybrid modeling technique which encompasses both radiation and optical effects. Methods: Imaging performance in terms of the contrast-to-noise ratio (CNR) and spatial resolution of various hypothetical scintillator designs was examined through a hybrid technique involving Monte Carlo simulation of radiation transport in combination with simulation of optical gain distributions and optical point spread functions. The optical simulations employed optical parameters extracted from a best fit to measurement results reported in a previous investigation of a 1.13 cm thick, 1016 μm pitch prototype BGO segmented scintillator. All hypothetical designs employed BGO material with a thickness and element-to-element pitch ranging from 0.5 to 6 cm and from 0.508 to 1.524 mm, respectively. In the CNR study, for each design, full tomographic scans of a contrast phantom incorporating various soft-tissue inserts were simulated at a total dose of 4 cGy. Results: Theoretical values for contrast, noise, and CNR were found to be in close agreement with empirical results from the BGO prototype, strongly supporting the validity of the modeling technique. CNR and spatial resolution for the various scintillator designs demonstrate complex behavior as scintillator thickness and element pitch are varied—with a clear trade-off between these two imaging metrics up to a thickness of ∼3 cm. Based on these results, an

  19. Optimization of the design of thick, segmented scintillators for megavoltage cone-beam CT using a novel, hybrid modeling technique

    SciTech Connect

    Liu, Langechuan; Antonuk, Larry E. El-Mohri, Youcef; Zhao, Qihua; Jiang, Hao

    2014-06-15

    Purpose: Active matrix flat-panel imagers (AMFPIs) incorporating thick, segmented scintillators have demonstrated order-of-magnitude improvements in detective quantum efficiency (DQE) at radiotherapy energies compared to systems based on conventional phosphor screens. Such improved DQE values facilitate megavoltage cone-beam CT (MV CBCT) imaging at clinically practical doses. However, the MV CBCT performance of such AMFPIs is highly dependent on the design parameters of the scintillators. In this paper, optimization of the design of segmented scintillators was explored using a hybrid modeling technique which encompasses both radiation and optical effects. Methods: Imaging performance in terms of the contrast-to-noise ratio (CNR) and spatial resolution of various hypothetical scintillator designs was examined through a hybrid technique involving Monte Carlo simulation of radiation transport in combination with simulation of optical gain distributions and optical point spread functions. The optical simulations employed optical parameters extracted from a best fit to measurement results reported in a previous investigation of a 1.13 cm thick, 1016μm pitch prototype BGO segmented scintillator. All hypothetical designs employed BGO material with a thickness and element-to-element pitch ranging from 0.5 to 6 cm and from 0.508 to 1.524 mm, respectively. In the CNR study, for each design, full tomographic scans of a contrast phantom incorporating various soft-tissue inserts were simulated at a total dose of 4 cGy. Results: Theoretical values for contrast, noise, and CNR were found to be in close agreement with empirical results from the BGO prototype, strongly supporting the validity of the modeling technique. CNR and spatial resolution for the various scintillator designs demonstrate complex behavior as scintillator thickness and element pitch are varied—with a clear trade-off between these two imaging metrics up to a thickness of ∼3 cm. Based on these results, an

  20. Development of a Versatile Laser Ultrasonic System and Application to On-Line Measurement for Process Control of Wall Thickness and Eccentrictiy of Steel Seamless Mechanical Tubing

    SciTech Connect

    Kisner, R.A.; Kercel, S.W.; Damiano, B.; Bingham, P.R.; Gee, T.F.; Tucker, R.W.; Moore, M.R.; Hileman, M.; Emery, M.; Lenarduzzi, R.; Hardy, J.E.; Weaver, K.; Crutcher, R.; Kolarik, R.V., II; Vandervaart, R.H.

    2002-04-24

    Researchers at the Timken Company conceived a project to develop an on-line instrument for wall thickness measurement of steel seamless mechanical tubing based on laser ultrasonic technology. The instrument, which has been installed and tested at a piercing mill, provides data on tube eccentricity and concentricity. Such measurements permit fine-tuning of manufacturing processes to eliminate excess material in the tube wall and therefore provide a more precisely dimensioned product for their customers. The resulting process energy savings are substantial, as is lowered environmental burden. The expected savings are $85.8 million per year in seamless mechanical tube piercing alone. Applied across the industry, this measurement has a potential of reducing energy consumption by 6 x 10{sup 12} BTU per year, greenhouse gas emissions by 0.3 million metric tons carbon equivalent per year, and toxic waste by 0.255 million pounds per year. The principal technical contributors to the project were the Timken Company, Industrial Materials Institute (IMI, a contractor to Timken), and Oak Ridge National Laboratory (ORNL). Timken provided mill access as well as process and metallurgical understanding. Timken researchers had previously developed fundamental ultrasonic analysis methods on which this project is based. IMI developed and fabricated the laser ultrasonic generation and receiver systems. ORNL developed Bayesian and wavelet based real-time signal processing, spread-spectrum wireless communication, and explored feature extraction and pattern recognition methods. The resulting instrument has successfully measured production tubes at one of Timken's piercing mills. This report concentrates on ORNL's contribution through the CRADA mechanism. The three components of ORNL's contribution were met with mixed success. The real-time signal-processing task accomplished its goal of improvement in detecting time of flight information with a minimum of false data. The signal processing

  1. Single-wall carbon nanotubes under high pressures to 62 GPa studied using designer diamond anvils.

    PubMed

    Patterson, J R; Vohra, Y K; Weir, S T; Akella, J

    2001-06-01

    Single-wall carbon nanotube samples were studied under high pressures to 62 GPa using designer diamond anvils with buried electrical microprobes that allowed for monitoring of the four-probe electrical resistance at elevated pressure. After initial densification, the electrical resistance shows a steady increase from 3 to 42 GPa, followed by a sharp rise above 42 GPa. This sharp rise in electrical resistance at high pressures is attributed to opening of an energy band gap with compression. Nanoindentation hardness measurements on the pressure-treated carbon nanotube samples gave a hardness value of 0.50 +/- 0.03 GPa. This hardness value is approximately 2 orders of magnitude lower than the amorphous carbon phase produced in fullerenes under similar conditions. Therefore, the pressure treatment of single-wall carbon nanotubes to 62 GPa did not produce a superhard carbon phase.

  2. The DDBD Method In The A-Seismic Design of Anchored Diaphragm Walls

    SciTech Connect

    Manuela, Cecconi; Vincenzo, Pane; Sara, Vecchietti

    2008-07-08

    The development of displacement based approaches for earthquake engineering design appears to be very useful and capable to provide improved reliability by directly comparing computed response and expected structural performance. In particular, the design procedure known as the Direct Displacement Based Design (DDBD) method, which has been developed in structural engineering over the past ten years in the attempt to mitigate some of the deficiencies in current force-based design methods, has been shown to be very effective and promising ([1], [2]). The first attempts of application of the procedure to geotechnical engineering and, in particular, earth retaining structures are discussed in [3], [4] and [5]. However in this field, the outcomes of the research need to be further investigated in many aspects. The paper focuses on the application of the DDBD method to anchored diaphragm walls. The results of the DDBD method are discussed in detail in the paper, and compared to those obtained from conventional pseudo-static analyses.

  3. Design, construction and performance evaluation of the target tissue thickness measurement system in intraoperative radiotherapy for breast cancer

    NASA Astrophysics Data System (ADS)

    Yazdani, Mohammad Reza; Setayeshi, Saeed; Arabalibeik, Hossein; Akbari, Mohammad Esmaeil

    2017-05-01

    Intraoperative electron radiation therapy (IOERT), which uses electron beams for irradiating the target directly during the surgery, has the advantage of delivering a homogeneous dose to a controlled layer of tissue. Since the dose falls off quickly below the target thickness, the underlying normal tissues are spared. In selecting the appropriate electron energy, the accuracy of the target tissue thickness measurement is critical. In contrast to other procedures applied in IOERT, the routine measurement method is considered to be completely traditional and approximate. In this work, a novel mechanism is proposed for measuring the target tissue thickness with an acceptable level of accuracy. An electronic system has been designed and manufactured with the capability of measuring the tissue thickness based on the recorded electron density under the target. The results indicated the possibility of thickness measurement with a maximum error of 2 mm for 91.35% of data. Aside from system limitation in estimating the thickness of 5 mm phantom, for 88.94% of data, maximum error is 1 mm.

  4. Displacement-based seismic design of flat slab-shear wall buildings

    NASA Astrophysics Data System (ADS)

    Sen, Subhajit; Singh, Yogendra

    2016-06-01

    Flat slab system is becoming widely popular for multistory buildings due to its several advantages. However, the performance of flat slab buildings under earthquake loading is unsatisfactory due to their vulnerability to punching shear failure. Several national design codes provide guidelines for designing flat slab system under gravity load only. Nevertheless, flat slab buildings are also being constructed in high seismicity regions. In this paper, performance of flat slab buildings of various heights, designed for gravity load alone according to code, is evaluated under earthquake loading as per ASCE/SEI 41 methodology. Continuity of slab bottom reinforcement through column cage improves the performance of flat slab buildings to some extent, but it is observed that these flat slab systems are not adequate in high seismicity areas and need additional primary lateral load resisting systems such as shear walls. A displacement-based method is proposed to proportion shear walls as primary lateral load resisting elements to ensure satisfactory performance. The methodology is validated using design examples of flat slab buildings with various heights.

  5. Design considerations for a high-power, short rise-time pulser for thick-transducer applications

    NASA Astrophysics Data System (ADS)

    Gammell, Paul M.; Harris, Gerald R.

    2002-05-01

    When transiently-excited, thick ultrasonic source transducers are used in NDE applications, such as broadband measurements of attenuation or of directivity and frequency responses of receiving transducers, the pulser must provide an excitation pulse that is very short and of high voltage and current. Also, it is desirable that the pulser be of simple and stable design. Features of several designs, including modern FET pulser circuits, are discussed.

  6. Drought-induced increase in water-use efficiency reduces secondary tree growth and tracheid wall thickness in a Mediterranean conifer.

    PubMed

    Olano, José Miguel; Linares, Juan Carlos; García-Cervigón, Ana I; Arzac, Alberto; Delgado, Antonio; Rozas, Vicente

    2014-09-01

    In order to understand the impact of drought and intrinsic water-use efficiency (iWUE) on tree growth, we evaluated the relative importance of direct and indirect effects of water availability on secondary growth and xylem anatomy of Juniperus thurifera, a Mediterranean anisohydric conifer. Dendrochronological techniques, quantitative xylem anatomy, and (13)C/(12)C isotopic ratio were combined to develop standardized chronologies for iWUE, BAI (basal area increment), and anatomical variables on a 40-year-long annually resolved series for 20 trees. We tested the relationship between iWUE and secondary growth at short-term (annual) and long-term (decadal) temporal scales to evaluate whether gains in iWUE may lead to increases in secondary growth. We obtained a positive long-term correlation between iWUE and BAI, simultaneously with a negative short-term correlation between them. Furthermore, BAI and iWUE were correlated with anatomical traits related to carbon sink or storage (tracheid wall thickness and ray parenchyma amount), but no significant correlation with conductive traits (tracheid lumen) was found. Water availability during the growing season significantly modulated tree growth at the xylem level, where growth rates and wood anatomical traits were affected by June precipitation. Our results are consistent with a drought-induced limitation of tree growth response to rising CO2, despite the trend of rising iWUE being maintained. We also remark the usefulness of exploring this relationship at different temporal scales to fully understand the actual links between iWUE and secondary growth dynamics.

  7. B-mode sonography wall thickness assessment of the temporal and axillary arteries for the diagnosis of giant cell arteritis: a cohort study.

    PubMed

    Czihal, Michael; Schröttle, Angelika; Baustel, Kerstin; Lottspeich, Christian; Dechant, Claudia; Treitl, Karla-Maria; Treitl, Marcus; Schulze-Koops, Hendrik; Hoffmann, Ulrich

    2017-01-01

    We aimed to determine the diagnostic accuracy of B-mode compression sonography of the temporal arteries (tempCS) and B-mode sonographic measurement of the axillary artery intima media thickness (axIMT) for the diagnosis of giant cell arteritis (GCA). After having established measurement of tempCS and axIMT in our routine diagnostic workup, 92 consecutive patients with a suspected diagnosis of GCA were investigated. Clinical characteristics were recorded and wall thickening of the temporal arteries (tempCS) and axillary arteries (axIMT) was measured (mm). Using the final clinical diagnosis as the reference standard, receiver operator characteristics (ROC) analysis was performed. In a subgroup of 26 patients interobserver agreement was assessed using Spearman's rank correlation. Cranial GCA, extracranial GCA, and combined cranial/extracranial GCA were diagnosed in 18, 7, and 9 individuals, respectively. For the diagnosis of cranial GCA, tempCS had an excellent area under the curve (AUC) of 0.95, with a cut-off of ≥0.7 mm offering a sensitivity and specificity of 85% and 95%. The AUC of axIMT for the diagnosis of extracranial GCA was 0.91 (cut-off ≥1.2 mm: sensitivity and specificity 81.3 and 96.1%). Applying a combined tempCS/axIMT cut-off of ≥0.7mm/1.2 mm, we calculated an overall sensitivity and specificity for the final clinical diagnosis of cranial and/or extracranial GCA of 85.3% and 91.4%. Interobserver agreement was strong for both parameters assessed (Spearman's rho 0.72 and 0.77, respectively). The combination of tempCS/axIMT allows objective sonographic assessment in suspected GCA with promising diagnostic accuracy.

  8. Longitudinal changes in structural abnormalities using MDCT in COPD: do the CT measurements of airway wall thickness and small pulmonary vessels change in parallel with emphysematous progression?

    PubMed Central

    Takayanagi, Shin; Kawata, Naoko; Tada, Yuji; Ikari, Jun; Matsuura, Yukiko; Matsuoka, Shin; Matsushita, Shoichiro; Yanagawa, Noriyuki; Kasahara, Yasunori; Tatsumi, Koichiro

    2017-01-01

    Background Recent advances in multidetector computed tomography (MDCT) facilitate acquiring important clinical information for managing patients with COPD. MDCT can detect the loss of lung tissue associated with emphysema as a low-attenuation area (LAA) and the thickness of airways as the wall area percentage (WA%). The percentage of small pulmonary vessels <5 mm2 (% cross-sectional area [CSA] <5) has been recently recognized as a parameter for expressing pulmonary perfusion. We aimed to analyze the longitudinal changes in structural abnormalities using these CT parameters and analyze the effect of exacerbation and smoking cessation on structural changes in COPD patients. Methods We performed pulmonary function tests (PFTs), an MDCT, and a COPD assessment test (CAT) in 58 patients with COPD at the time of their enrollment at the hospital and 2 years later. We analyzed the change in clinical parameters including CT indices and examined the effect of exacerbations and smoking cessation on the structural changes. Results The CAT score and forced expiratory volume in 1 second (FEV1) did not significantly change during the follow-up period. The parameters of emphysematous changes significantly increased. On the other hand, the WA% at the distal airways significantly decreased or tended to decrease, and the %CSA <5 slightly but significantly increased over the same period, especially in ex-smokers. The parameters of emphysematous change were greater in patients with exacerbations and continued to progress even after smoking cessation. In contrast, the WA% and %CSA <5 did not change in proportion to emphysema progression. Conclusion The WA% at the distal bronchi and the %CSA <5 did not change in parallel with parameters of LAA over the same period. We propose that airway disease and vascular remodeling may be reversible to some extent by smoking cessation and appropriate treatment. Optimal management may have a greater effect on pulmonary vascularity and airway disease

  9. Low-speed aerodynamic characteristics of a 17-percent-thick medium speed airfoil designed for general aviation applications

    NASA Technical Reports Server (NTRS)

    Mcghee, R. J.; Beaseley, W. D.

    1980-01-01

    Wind tunnel tests were conducted to determine the low speed two dimensional aerodynamic characteristics of a 17 percent thick medium speed airfoil (MS(1)-0317) designed for general aviation applications. The results were compared with data for the 17 percent thick low speed airfoil (LS(1)-0417) and the 13 percent thick medium speed airfoil (MS(1)-0313). Theoretical predictions of the drag rise characteristics of this airfoil are also provided. The tests were conducted in the Langley low turbulence pressure tunnel over a Mach number range from 0.10 to 0.32, a chord Reynolds number range from 2 million to 12 million, and an angle of attack range from about -8 to 20 deg.

  10. Impact of polymer film thickness and cavity size on polymer flow during embossing : towards process design rules for nanoimprint lithography.

    SciTech Connect

    Schunk, Peter Randall; King, William P. (Georgia Institute of Technology, Atlanta, GA); Sun, Amy Cha-Tien; Rowland, Harry D.

    2006-08-01

    This paper presents continuum simulations of polymer flow during nanoimprint lithography (NIL). The simulations capture the underlying physics of polymer flow from the nanometer to millimeter length scale and examine geometry and thermophysical process quantities affecting cavity filling. Variations in embossing tool geometry and polymer film thickness during viscous flow distinguish different flow driving mechanisms. Three parameters can predict polymer deformation mode: cavity width to polymer thickness ratio, polymer supply ratio, and Capillary number. The ratio of cavity width to initial polymer film thickness determines vertically or laterally dominant deformation. The ratio of indenter width to residual film thickness measures polymer supply beneath the indenter which determines Stokes or squeeze flow. The local geometry ratios can predict a fill time based on laminar flow between plates, Stokes flow, or squeeze flow. Characteristic NIL capillary number based on geometry-dependent fill time distinguishes between capillary or viscous driven flows. The three parameters predict filling modes observed in published studies of NIL deformation over nanometer to millimeter length scales. The work seeks to establish process design rules for NIL and to provide tools for the rational design of NIL master templates, resist polymers, and process parameters.

  11. Manipulation of zebrafish's orientation using artificial cilia in a microchannel with actively adaptive wall design.

    PubMed

    Mani, Karthick; Chang Chien, Tsung-Chun; Panigrahi, Bivas; Chen, Chia-Yuan

    2016-11-08

    The zebrafish is a powerful genetic model organism especially in the biomedical chapter for new drug discovery and development. The genetic toolbox which this vertebrate possesses opens a new window to investigate the etiology of human diseases with a high degree genetic similarity. Still, the requirements of laborious and time-consuming of contemporary zebrafish processing assays limit the procedure in carrying out such genetic screen at high throughput. Here, a zebrafish control scheme was initiated which includes the design and validation of a microfluidic platform to significantly increase the throughput and performance of zebrafish larvae manipulation using the concept of artificial cilia actuation. A moving wall design was integrated into this microfluidic platform first time in literature to accommodate zebrafish inside the microchannel from 1 day post-fertilization (dpf) to 6 dpf and can be further extended to 9 dpf for axial orientation control in a rotational range between 0 to 25 degrees at the minimum step of 2-degree increment in a stepwise manner. This moving wall feature was performed through the deflection of shape memory alloy wire embedded inside the microchannel controlled by the electrical waveforms with high accuracy.

  12. Determination of the chest wall thicknesses and needle thoracostomy success rates at second and fifth intercostal spaces: a cadaver-based study.

    PubMed

    Ozen, Can; Akoglu, Haldun; Ozdemirel, Rifat Ozgur; Omeroglu, Elif; Ozpolat, Cigdem Ulubay; Onur, Ozge; Buyuk, Yalcin; Denizbasi, Arzu

    2016-12-01

    The purposes of this study were to measure the chest wall thicknesses (CWTs) at second intercostal space (ICS) mid-clavicular line (MCL) and fifth ICS MAL directly, and compare the actual success rates of needle thoracostomies (NTs) by inserting a 5-cm-long syringe needle. Predictive values of weight, body mass index (BMI) and CWT were also analyzed. This study included 199 measurements of 50 adult fresh cadavers from both hemithoraces. Five-centimeter-long syringe needles were inserted and secured. Penetration into the pleural cavity was assessed, and CWTs at 4 locations were measured. Achieved power of this study for the primary aim of CWT comparison from 2(nd) and 5(th) ICSs was .94. Overall mean CWTs at 2(nd) ICS MCL and 5(th) ICS MAL were measured as 2.46 ± 0.78 and 2.89 ± 1.09, respectively, and 5(th) ICS MAL was found to be statistically thicker (P = .002). The success rate of NT at 2(nd) ICS MCL was 87% (95% CI, 80-94), and that at 5(th) ICS MAL was 78% (95% CI, 70-86; P = .3570). Only 6 (17.1%) of 35 failed NTs had a CWT greater than 5-cm. Needle thoracostomy has failed in 29 (14.9%) of 194 locations, despite a CWT less than 5-cm. Below a weight of 72 kg, BMI of 23 kg/m(2), or CWT of 2.4 cm, all NTs were successful. In this report, we present the largest cadaver-based cohort to date to the best of our knowledge, and we observed a statistically nonsignificant 9% more NT success rate at 2(nd) ICS at a power of 88% and statistically significant more success rate in males at 5(th) ICS was (47.7%). We also observed thinner CWTs and higher success rates than previous imaging-based studies. A BMI of 23 kg/m(2) or less and weight of 72 kg or less seem to accurately rule-out NT failure in cadavers, and they seem to be better predictors at the bedside. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Low-speed aerodynamic characteristics of a 13 percent thick medium speed airfoil designed for general aviation applications

    NASA Technical Reports Server (NTRS)

    Mcghee, R. J.; Beasley, W. D.

    1979-01-01

    Wind tunnel tests were conducted to determine the low speed, two dimensional aerodynamic characteristics of a 13percent thick medium speed airfoil designed for general aviation applications. The results were compared with data for the 13 percent thick low speed airfoil. The tests were conducted over a Mach number range from 0.10 to 0.32, a chord Reynolds number range from 2.0 x 10 to the 6th power to 12.0 x 10 to the 6th power, and an angle of attack frange from about -8 deg to 10 deg. The objective of retaining good high-lift low speed characteristics for an airfoil designed to have good medium speed cruise performance was achieved.

  14. Optical coherence tomography-guided retinal prosthesis design: model of degenerated retinal curvature and thickness for patient-specific devices.

    PubMed

    Opie, Nicholas L; Ayton, Lauren N; Apollo, Nicholas V; Ganesan, Kumaravelu; Guymer, Robyn H; Luu, Chi D

    2014-06-01

    Retinitis pigmentosa affects over 1.5 million people worldwide and is a leading cause of vision loss and blindness. While retinal prostheses have shown some success in restoring basic levels of vision, only generic, "one-size-fits-all" devices are currently being implanted. In this study, we used optical coherence tomography scans of the degenerated retina from 88 patients with retinitis pigmentosa to generate models of retinal thickness and curvature for the design of customized implants. We found the average retinal thickness at the fovea to be 152.9 ± 61.3 μm, increasing to a maximum retinal thickness of 250.9 ± 57.5 μm at a nasal eccentricity of 5°. These measures could be used to assist the development of custom-made penetrating electrodes to enhance and optimize epiretinal prostheses. From the retinal thickness measurements, we determined that the optimal length of penetrating electrodes to selectively stimulate retinal ganglion cell bodies and interneuron axons in the ganglion cell layer should be 30-100 μm, and to preferentially stimulate interneurons in the inner nuclear layer, electrodes should be 100-200 μm long. Electrodes greater than 200 μm long had the potential to penetrate through the retina into the choroid, which could cause devastating complications to the eye and should be avoided. The two- and three-dimensional models of retinal thickness developed in this study can be used to design patient-specific epiretinal implants that will help with safety and to optimize the efficacy of neuronal stimulation, ensuring the best functional performance of the device for patients.

  15. SCALE/MAVRIC calculation of dose rates measured for a gamma radiation source in a thick-walled transport and storage cask of ductile cast iron with lead inserts

    NASA Astrophysics Data System (ADS)

    Baumgarten, Werner; Thiele, Holger; Ruprecht, Benjamin; Phlippen, Peter-W.; Schlömer, Luc

    2017-09-01

    Dose rate calculations are important for judging the shielding performance of transport casks for radioactive material. Therefore it is important to have reliable calculation tools. We report on measured and calculated dose rates near a thick-walled transport and storage cask of ductile cast iron with lead inserts and a Co-60 source inside. In a series of experiments the thickness of the inserts was varied, and measured dose rates near the cask were compared with SCALE/MAVRIC 6.1.3 and SCALE/MAVRIC 6.2 calculation results. Deviations from the measurements were found to be higher for increased lead thicknesses. Furthermore, it is shown how the shielding material density, air scattering and accounting for the floor influence the quality of the calculation.

  16. Remote sensing of sea ice thickness by a combined spatial and frequency domain interferometer : formulations, instrument design & development

    NASA Technical Reports Server (NTRS)

    Hussein, Ziad A.; Holt, Benjamin; McDonald, Kyle C.; Jordan, Rolando; Huang, John; Kuga, Yasuo; Ishimaru, Akira; Jaruwatanadilok, Sermsak; Gogineni, Prasad; Heavey, Brandon; Akins, Torry; Perovich, Don; Sturm, Matthew

    2005-01-01

    The thickness of Arctic sea ice plays a critical role in Earth's climate and ocean circulation. An accurate measurement of this parameter on synoptic scales at regular intervals would enable characterization of this important component for the understanding of ocean circulation and the global heat balance. Presented in this paper is a low frequency VHF interferometer technique and associated radar instrument design to measure sea ice thickness based on the use of backscatter correlation functions. The sea ice medium is represented as a multi-layered medium consisting of snow, seaice and sea water, with the interfaces between layers characterized as rough surfaces. This technique utilizes the correlation of two radar waves of different frequencies and incident and observation angles, scattered from the sea ice medium. The correlation functions relate information about the sea ice thickness. Inversion techniques such as the genetic algorithm, gradient descent, and least square methods, are used to derive sea ice thickness from the phase information related by the correlation functions.

  17. Remote sensing of sea ice thickness by a combined spatial and frequency domain interferometer : formulations, instrument design & development

    NASA Technical Reports Server (NTRS)

    Hussein, Ziad A.; Holt, Benjamin; McDonald, Kyle C.; Jordan, Rolando; Huang, John; Kuga, Yasuo; Ishimaru, Akira; Jaruwatanadilok, Sermsak; Gogineni, Prasad; Heavey, Brandon; hide

    2005-01-01

    The thickness of Arctic sea ice plays a critical role in Earth's climate and ocean circulation. An accurate measurement of this parameter on synoptic scales at regular intervals would enable characterization of this important component for the understanding of ocean circulation and the global heat balance. Presented in this paper is a low frequency VHF interferometer technique and associated radar instrument design to measure sea ice thickness based on the use of backscatter correlation functions. The sea ice medium is represented as a multi-layered medium consisting of snow, seaice and sea water, with the interfaces between layers characterized as rough surfaces. This technique utilizes the correlation of two radar waves of different frequencies and incident and observation angles, scattered from the sea ice medium. The correlation functions relate information about the sea ice thickness. Inversion techniques such as the genetic algorithm, gradient descent, and least square methods, are used to derive sea ice thickness from the phase information related by the correlation functions.

  18. Methodology of design and analysis of external walls of space station for hypervelocity impacts by meteoroids and space debris

    NASA Technical Reports Server (NTRS)

    Batla, F. A.

    1986-01-01

    The development of criteria and methodology for the design and analysis of Space Station wall elements for collisions with meteoroids and space debris at hypervelocities is discussed. These collisions will occur at velocities of 10 km/s or more and can be damaging to the external wall elements of the Space Station. The wall elements need to be designed to protect the pressurized modules of the Space Station from functional or structural failure due to these collisions at hypervelocities for a given environment and population of meteoroids and space debris. The design and analysis approach and the associated computer program presented is to achieve this objective, including the optimization of the design for a required overall probability of no penetration. The approach is based on the presently available experimental and actual data on meteoroids and space debris flux and damage assessments and the empirical relationships resulting from the hypervelocity impact studies in laboratories.

  19. Long term organ culture of human prostate tissue in a NASA-designed rotating wall bioreactor

    NASA Technical Reports Server (NTRS)

    Margolis, L.; Hatfill, S.; Chuaqui, R.; Vocke, C.; Emmert-Buck, M.; Linehan, W. M.; Duray, P. H.

    1999-01-01

    PURPOSE: To maintain ex vivo integral prostatic tissue including intact stromal and ductal elements using the NASA-designed Rotating Wall Vessel (RWV) which maintains colocalized cells in an environment that promotes both three-dimensional cellular interactions together with the uniform mass transfer of nutrients and metabolic wastes. MATERIALS AND METHODS: Samples of normal prostate were obtained as a byproduct of transurethral prostatectomy or needle biopsy. Prostatic tissue dissected into small 1 x 1 mm. blocks was cultured in the Rotating Wall Vessel (RWV) Bioreactor for various time periods and analyzed using histological, immunochemical, and total cell RNA assays. RESULTS: We report the long term maintenance of benign explanted human prostate tissue grown in simple culture medium, under the simulated microgravity conditions afforded by the RWV bioreactor. Mesenchymal stromal elements including blood vessels and architecturally preserved tubuloglandular acini were maintained for a minimum of 28 days. Cytokeratins, vimentin and TGF-beta2 receptor and ligand were preserved through the entire culture period as revealed by immunocytochemistry. Prostatic acid phosphatase (PAP) was continuously expressed during the culture period, although somewhat decreased. Prostatic specific antigen (PSA) and its transcript were down regulated over time of culture. Prostatic carcinoma cells from the TSU cell line were able to invade RWV-cultured benign prostate tissue explants. CONCLUSIONS: The RWV bioreactor represents an additional new technology for culturing prostate tissue for further investigations concerning the basic physiology and pathobiology of this clinically important tissue.

  20. Long term organ culture of human prostate tissue in a NASA-designed rotating wall bioreactor.

    PubMed

    Margolis, L; Hatfill, S; Chuaqui, R; Vocke, C; Emmert-Buck, M; Linehan, W M; Duray, P H

    1999-01-01

    To maintain ex vivo integral prostatic tissue including intact stromal and ductal elements using the NASA-designed Rotating Wall Vessel (RWV) which maintains colocalized cells in an environment that promotes both three-dimensional cellular interactions together with the uniform mass transfer of nutrients and metabolic wastes. Samples of normal prostate were obtained as a byproduct of transurethral prostatectomy or needle biopsy. Prostatic tissue dissected into small 1 x 1 mm. blocks was cultured in the Rotating Wall Vessel (RWV) Bioreactor for various time periods and analyzed using histological, immunochemical, and total cell RNA assays. We report the long term maintenance of benign explanted human prostate tissue grown in simple culture medium, under the simulated microgravity conditions afforded by the RWV bioreactor. Mesenchymal stromal elements including blood vessels and architecturally preserved tubuloglandular acini were maintained for a minimum of 28 days. Cytokeratins, vimentin and TGF-beta2 receptor and ligand were preserved through the entire culture period as revealed by immunocytochemistry. Prostatic acid phosphatase (PAP) was continuously expressed during the culture period, although somewhat decreased. Prostatic specific antigen (PSA) and its transcript were down regulated over time of culture. Prostatic carcinoma cells from the TSU cell line were able to invade RWV-cultured benign prostate tissue explants. The RWV bioreactor represents an additional new technology for culturing prostate tissue for further investigations concerning the basic physiology and pathobiology of this clinically important tissue.

  1. Long term organ culture of human prostate tissue in a NASA-designed rotating wall bioreactor

    NASA Technical Reports Server (NTRS)

    Margolis, L.; Hatfill, S.; Chuaqui, R.; Vocke, C.; Emmert-Buck, M.; Linehan, W. M.; Duray, P. H.

    1999-01-01

    PURPOSE: To maintain ex vivo integral prostatic tissue including intact stromal and ductal elements using the NASA-designed Rotating Wall Vessel (RWV) which maintains colocalized cells in an environment that promotes both three-dimensional cellular interactions together with the uniform mass transfer of nutrients and metabolic wastes. MATERIALS AND METHODS: Samples of normal prostate were obtained as a byproduct of transurethral prostatectomy or needle biopsy. Prostatic tissue dissected into small 1 x 1 mm. blocks was cultured in the Rotating Wall Vessel (RWV) Bioreactor for various time periods and analyzed using histological, immunochemical, and total cell RNA assays. RESULTS: We report the long term maintenance of benign explanted human prostate tissue grown in simple culture medium, under the simulated microgravity conditions afforded by the RWV bioreactor. Mesenchymal stromal elements including blood vessels and architecturally preserved tubuloglandular acini were maintained for a minimum of 28 days. Cytokeratins, vimentin and TGF-beta2 receptor and ligand were preserved through the entire culture period as revealed by immunocytochemistry. Prostatic acid phosphatase (PAP) was continuously expressed during the culture period, although somewhat decreased. Prostatic specific antigen (PSA) and its transcript were down regulated over time of culture. Prostatic carcinoma cells from the TSU cell line were able to invade RWV-cultured benign prostate tissue explants. CONCLUSIONS: The RWV bioreactor represents an additional new technology for culturing prostate tissue for further investigations concerning the basic physiology and pathobiology of this clinically important tissue.

  2. Design of the PDX Tokamak wall armor and inner limiter system

    SciTech Connect

    Kugel, H.W.; Ulrickson, M.

    1981-08-01

    The inner wall protective plates for the PDX Tokamak are designed to absorb 8 MW of neutral deuterium beam power at maximum power densities of 3 kW/cm/sup 2/ for pulse lengths of 0.5 sec. Preliminary studies indicate that the design could survive several pulses of 1 sec duration. The design consists of a tile and mounting plate structure. The mounting plates are water cooled to allow short duty cycles and beam calorimetry. The temperature and flow of the coolant is measured to obtain the injected power. A thermocouple array on the tiles provides beam position and power density profiles. Several material combinations for the tiles were subjected to thermal tests using both electron and neutral beams, and titanium carbide coated graphite was selected as the tile material. The heat transfer coefficient of the tile backing plate structure was measured to determine the maximum pulse rate allowable. The design of the armor system allows the structure to be used as a neutral beam power diagnostic and as an inner plasma limiter. The electrical and cooling systems external to the vacuum vessel are discussed.

  3. Fermion localization on thick branes

    SciTech Connect

    Melfo, Alejandra; Pantoja, Nelson; Tempo, Jose David

    2006-02-15

    We consider chiral fermion confinement in scalar thick branes, which are known to localize gravity, coupled through a Yukawa term. The conditions for the confinement and their behavior in the thin-wall limit are found for various different BPS branes, including double walls and branes interpolating between different AdS{sub 5} spacetimes. We show that only one massless chiral mode is localized in all these walls, whenever the wall thickness is keep finite. We also show that, independently of wall's thickness, chiral fermionic modes cannot be localized in dS{sub 4} walls embedded in a M{sub 5} spacetime. Finally, massive fermions in double wall spacetimes are also investigated. We find that, besides the massless chiral mode localization, these double walls support quasilocalized massive modes of both chiralities.

  4. A new designed π conjugated molecule for stable single walled carbon nanotube dispersion in aqueous medium.

    PubMed

    Nogueira, S L; Sahoo, S K; Jarrosson, T; Serein-Spirau, F; Lère-Porte, J-P; Moujaes, E A; Marletta, A; Santos, A P; Fantini, C; Furtado, C A; Silva, R A

    2016-02-15

    A molecule with a π conjugated backbone built from aromatic thiophene and dialkoxyphenylene units and substituted imidazolium groups (TPO) is designed to obtain ultra-stable single walled carbon nanotube (SWCNT) dispersion in aqueous medium. The proposed mechanism of non-covalent interaction is accompanied by individualization of SWCNT and comprises of dominant nondisruptive π-π and cation-π interaction between them and the TPO conjugated oligomer. The individualization of SWCNT and dispersibility and stability of the ultra-stable suspensions were estimated using high resolution transmission electron microscopy, UV-Visible-NIR absorption spectroscopy, Raman spectroscopy, photoluminescence and zeta potential measurement. Nuclear magnetic resonance data provides direct evidence toward possible cation-π interaction.

  5. Simulation and design of feedback control on resistive wall modes in Keda Torus eXperiment

    SciTech Connect

    Li, Chenguang; Liu, Wandong; Li, Hong

    2014-12-15

    The feedback control of resistive wall modes (RWMs) in Keda Torus eXperiment (KTX) (Liu et al., Plasma Phys. Controlled Fusion 56, 094009 (2014)) is investigated by simulation. A linear model is built to describe the growth of the unstable modes in the absence of feedback and the resulting mode suppression due to feedback, given the typical reversed field pinch plasma equilibrium. The layout of KTX with two shell structures (the vacuum vessel and the stabilizing shell) is taken into account. The feedback performance is explored both in the scheme of “clean mode control” (Zanca et al., Nucl. Fusion 47, 1425 (2007)) and “raw mode control.” The discrete time control model with specific characteristic times will mimic the real feedback control action and lead to the favored control cycle. Moreover, the conceptual design of feedback control system is also presented, targeting on both RWMs and tearing modes.

  6. Designing an optical set-up of differential laser triangulation for oil film thickness measurement on water.

    PubMed

    Ge, Baozhene; Sun, Jingbin; Liu, Pengcheng; Lü, Qieni; Wu, Di

    2013-01-01

    Based on the differential laser triangulation principle, an optical system configuration for measuring the oil film thickness on water is designed and developed. A semiconductor laser of 650 nm wavelength with the maximum power of 5 mW is used as a light source, the magnification of the imaging system is 1.4; the range of the measurement is 0.1 mm-10 mm; the resolution is 2.3 μm and the measurement accuracy is 10 μm theoretically. Experiments are conducted with block gauges and feeler gauges, and the experimental results, with absolute error less than ±25 μm and the maximal measurable thickness 12 mm, indicate that this system presented in this paper can fulfill high accuracy.

  7. Lateral Abdominal Wall Reconstruction

    PubMed Central

    Baumann, Donald P.; Butler, Charles E.

    2012-01-01

    Lateral abdominal wall (LAW) defects can manifest as a flank hernias, myofascial laxity/bulges, or full-thickness defects. These defects are quite different from those in the anterior abdominal wall defects and the complexity and limited surgical options make repairing the LAW a challenge for the reconstructive surgeon. LAW reconstruction requires an understanding of the anatomy, physiologic forces, and the impact of deinnervation injury to design and perform successful reconstructions of hernia, bulge, and full-thickness defects. Reconstructive strategies must be tailored to address the inguinal ligament, retroperitoneum, chest wall, and diaphragm. Operative technique must focus on stabilization of the LAW to nonyielding points of fixation at the anatomic borders of the LAW far beyond the musculofascial borders of the defect itself. Thus, hernias, bulges, and full-thickness defects are approached in a similar fashion. Mesh reinforcement is uniformly required in lateral abdominal wall reconstruction. Inlay mesh placement with overlying myofascial coverage is preferred as a first-line option as is the case in anterior abdominal wall reconstruction. However, interposition bridging repairs are often performed as the surrounding myofascial tissue precludes a dual layered closure. The decision to place bioprosthetic or prosthetic mesh depends on surgeon preference, patient comorbidities, and clinical factors of the repair. Regardless of mesh type, the overlying soft tissue must provide stable cutaneous coverage and obliteration of dead space. In cases where the fasciocutaneous flaps surrounding the defect are inadequate for closure, regional pedicled flaps or free flaps are recruited to achieve stable soft tissue coverage. PMID:23372458

  8. Fillability of Thin-Wall Steel Castings

    SciTech Connect

    Robert C. Voigt; Joseph Bertoletti; Andrew Kaley; Sandi Ricotta; Travis Sunday

    2002-07-30

    The use of steel components is being challenged by lighter nonferrous or cast iron components. The development of techniques for enhancing and ensuring the filability of thin-wall mold cavities is most critical for thinner wall cast steel production. The purpose of this research was to develop thin-wall casting techniques that can be used to reliably produce thin-wall castings from traditional gravity poured sand casting processes. The focus of the research was to enhance the filling behavior to prevent misrunds. Experiments were conducted to investigate the influence of various foundry variables on the filling of thin section steel castings. These variables include casting design, heat transfer, gating design, and metal fluidity. Wall thickness and pouring temperature have the greatest effect on casting fill. As wall thickness increases the volume to surface area of the casting increases, which increases the solidification time, allowing the metal to flow further in thicker sect ions. Pouring time is another significant variable affecting casting fill. Increases or decreases of 20% in the pouring time were found to have a significant effect on the filling of thin-wall production castings. Gating variables, including venting, pouring head height, and mold tilting also significantly affected thin-wall casting fill. Filters offer less turbulent, steadier flow, which is appropriate for thicker castings, but they do not enhance thin-wall casting fill.

  9. Study on thickness distribution of thermoformed medical PVC blister

    NASA Astrophysics Data System (ADS)

    Li, Yiping

    2017-08-01

    Vacuum forming has many advantages over other plastic forming processes due to its cost effectiveness, time efficiency, higher product precision, and more design flexibility. Nevertheless, when pressures greater than the atmospheric value are required to force the thermo-plastic into more intimate contact with the mold surface, pressure forming is a better choice. This paper studies the process of air-pressure thermoforming of plastic sheet, and focuses on medical blister PVC products. ANSYS POLYFLOW tool is used to simulate the process and analyze the wall thickness distribution of the blister. The influence of mold parameters on the wall thickness distribution of thermoformed part is thus obtained through simulation. Increasing radius between mold and side wall at the bottom of blister and draft prove to improve the wall thickness distribution.

  10. Are designer plant cell walls a realistic aspiration or will the plasticity of the plant's metabolism win out?

    PubMed

    Doblin, Monika S; Johnson, Kim L; Humphries, John; Newbigin, Ed J; Bacic, Antony

    2014-04-01

    Plants have been redesigned by humans since the advent of modern agriculture some 10000 years ago, to provide ever increasing benefits to society. The phenomenal success of the green revolution in converting biomass from vegetative tissues into grain yield has sustained a growing population. At the dawn of the 21st century the need to further optimise plant biomass (largely plant walls) for a sustainable future is increasingly evident as our supply of fossil fuels is finite and the quality of our crop-based foods (functional foods; also determined by the composition of walls) are critical to maintaining a healthy lifestyle. Our capacity to engineer 'designer walls' suited to particular purposes is challenging plant breeders and biotechnologists in unprecedented ways. In this review we provide an overview of the critical steps in the assembly and remodelling of walls, the success (or otherwise) of such approaches and highlight another complex network, the cell surface, as a cell wall integrity (CWI) sensor that exerts control over wall composition and will need to be considered in any future modification of walls for agro-industrial purposes.

  11. Superconducting magnetoresistance effect observed in Co/Nb/Co trilayers under a parallel magnetic field: The importance of matching the width of magnetic domain walls of the Co layers with the thickness of the Nb interlayer

    NASA Astrophysics Data System (ADS)

    Aristomenopoulou, E.; Stamopoulos, D.

    2015-08-01

    Magnetoresistance effects observed in ferromagnet/superconductor (FM/SC) hybrids, FM/SC bilayers (BLs) and FM/SC/FM trilayers (TLs), have attracted much interest. Here, we focus on the stray-fields-based superconducting magnetoresistance effect (sMRE) observed in Co(dCo)/Nb(dNb)/Co(dCo) TLs with sufficiently thick Co outer layers so that out-of-plane magnetic domains (MDs) and MDs walls (MDWs) emerge all over their surface when subjected to a parallel external magnetic field, Hex, equal to the coercive field, Hc. To explore the conditions necessary for maximization of the sMRE, we focus on the different kinds of the stray dipolar fields, Hdip, that emerge at the interior of the out-of-plane MDs and at the boundaries of MDWs; these have a different inherent tendency to create straight and semi-loop vortices, respectively. In the recent literature, the creation of straight and semi-loop vortices has been addressed at some extent both theoretically [Laiho et al., Phys. Rev. B 67, 144522 (2003)] and experimentally [Bobba et al., Phys. Rev. B 89, 214502 (2014)] for the case of FM/SC BLs. Here, we address these issues in FM/SC/FM TLs in connection to the sMRE. Specifically, we focus on an experimental finding reported recently [D. Stamopoulos and E. Aristomenopoulou, J. Appl. Phys. 116, 233908 (2014)]; strong magnetostatic coupling of the FM outer layers is accompanied by an intense sMRE in TLs in which the thickness of the SC interlayer, dSC, matches the width of MDWs, DMDWs. To investigate this finding, we employ simulations-modeling and energy-considerations and propose two quantitative criteria that facilitate the creation of straight vortices over semi-loop ones. The first focuses on the maximization of the stray Hdip that occur at the interior of the out-of-plane MDs. The second enables the estimation of a crossover between the preferable creation of one kind of vortices over the other. Both criteria respond well, when tested against experimental results. These

  12. Numerical design and optimization of hydraulic resistance and wall shear stress inside pressure-driven microfluidic networks.

    PubMed

    Damiri, Hazem Salim; Bardaweel, Hamzeh Khalid

    2015-11-07

    Microfluidic networks represent the milestone of microfluidic devices. Recent advancements in microfluidic technologies mandate complex designs where both hydraulic resistance and pressure drop across the microfluidic network are minimized, while wall shear stress is precisely mapped throughout the network. In this work, a combination of theoretical and modeling techniques is used to construct a microfluidic network that operates under minimum hydraulic resistance and minimum pressure drop while constraining wall shear stress throughout the network. The results show that in order to minimize the hydraulic resistance and pressure drop throughout the network while maintaining constant wall shear stress throughout the network, geometric and shape conditions related to the compactness and aspect ratio of the parent and daughter branches must be followed. Also, results suggest that while a "local" minimum hydraulic resistance can be achieved for a geometry with an arbitrary aspect ratio, a "global" minimum hydraulic resistance occurs only when the aspect ratio of that geometry is set to unity. Thus, it is concluded that square and equilateral triangular cross-sectional area microfluidic networks have the least resistance compared to all rectangular and isosceles triangular cross-sectional microfluidic networks, respectively. Precise control over wall shear stress through the bifurcations of the microfluidic network is demonstrated in this work. Three multi-generation microfluidic network designs are considered. In these three designs, wall shear stress in the microfluidic network is successfully kept constant, increased in the daughter-branch direction, or decreased in the daughter-branch direction, respectively. For the multi-generation microfluidic network with constant wall shear stress, the design guidelines presented in this work result in identical profiles of wall shear stresses not only within a single generation but also through all the generations of the

  13. Influence of preparation design and ceramic thicknesses on fracture resistance and failure modes of premolar partial coverage restorations.

    PubMed

    Guess, Petra C; Schultheis, Stefan; Wolkewitz, Martin; Zhang, Yu; Strub, Joerg R

    2013-10-01

    Preparation designs and ceramic thicknesses are key factors for the long-term success of minimally invasive premolar partial coverage restorations. However, only limited information is presently available on this topic. The purpose of this in vitro study was to evaluate the fracture resistance and failure modes of ceramic premolar partial coverage restorations with different preparation designs and ceramic thicknesses. Caries-free human premolars (n=144) were divided into 9 groups. Palatal onlay preparation comprised reduction of the palatal cusp by 2 mm (Palatal Onlay Standard), 1 mm (Palatal-Onlay-Thin), or 0.5 mm (Palatal Onlay Ultrathin). Complete-coverage onlay preparation additionally included the buccal cusp (Occlusal Onlay Standard; Occlusal Onlay Thin; Occlusal Onlay Ultrathin). Labial surface preparations with chamfer reductions of 0.8 mm (Complete-Veneer-Standard), 0.6 mm (Complete-Veneer-Thin), and 0.4 mm (Complete Veneer Ultrathin) were implemented for complete veneer restorations. Restorations were fabricated from a pressable lithium disilicate ceramic (IPS-e.max-Press) and cemented adhesively (Syntac-Classic/Variolink-II). All specimens were subjected to cyclic mechanical loading (F=49 N, 1.2 million cycles) and simultaneous thermocycling (5°C to 55°C) in a mouth-motion simulator. After fatigue, restorations were exposed to single-load-to-failure. Two-way ANOVA was used to identify statistical differences. Pair-wise differences were calculated and P-values were adjusted by the Tukey-Kramer method (α=.05). All specimens survived fatigue. Mean (SD) load to failure values (N) were as follows: 837 (320/Palatal-Onlay-Standard), 1055 (369/Palatal-Onlay-Thin), 1192 (342/Palatal-Onlay-Ultrathin), 963 (405/Occlusal-Onlay-Standard), 1108 (340/Occlusal-Onlay-Thin), 997 (331/Occlusal-Onlay-Ultrathin), 1361 (333/Complete-Veneer-Standard), 1087 (251/Complete-Veneer-Thin), 883 (311/Complete-Veneer-Ultrathin). Palatal-onlay restorations revealed a significantly

  14. Influence of preparation design and ceramic thicknesses on fracture resistance and failure modes of premolar partial coverage restorations

    PubMed Central

    Guess, Petra C.; Schultheis, Stefan; Wolkewitz, Martin; Zhang; Strub, Joerg R.

    2015-01-01

    Statement of problem Preparation designs and ceramic thicknesses are key factors for the long-term success of minimally invasive premolar partial coverage restorations. However, only limited information is presently available on this topic. Purpose The aim of this in vitro study was to evaluate the fracture resistance and failure modes of ceramic premolar partial coverage restorations with different preparation designs and ceramic thicknesses. Material and methods Caries-free human premolars (n= 144) were divided into 9 groups. Palatal onlay preparation comprised reduction of the palatal cusp by 2 mm (Palatal-Onlay-Standard), 1 mm (Palatal-Onlay-Thin), or 0.5 mm (Palatal-Onlay-Ultra-Thin). Complete-coverage onlay preparation additionally included the buccal cusp (Occlusal-Onlay-Standard; Occlusal-Onlay-Thin; Occlusal-Onlay-Ultra-Thin). Labial surface preparations with chamfer reductions of 0.8 mm (Complete-Veneer-Standard), 0.6 mm (Complete-Veneer-Thin) and 0.4 mm (Complete-Veneer-Ultra-Thin) were implemented for complete veneer restorations. Restorations were fabricated from a pressable lithium-disilicate ceramic (IPS-e.max-Press) and cemented adhesively (Syntac-Classic/Variolink-II). All specimens were subjected to cyclic mechanical loading (F= 49 N, 1.2 million cycles) and simultaneous thermocycling (5°C to 55°C) in a mouth-motion simulator. After fatigue, restorations were exposed to single-load-to-failure. Two-way ANOVA was used to identify statistical differences. Pair-wise differences were calculated and P-values were adjusted by the Tukey–Kramer method (α= .05). Results All specimens survived fatigue. Mean (SD) load to failure values (N) were as follows: 837 (320/Palatal-Onlay-Standard), 1055 (369/Palatal-Onlay-Thin), 1192 (342/Palatal-Onlay-Ultra-Thin), 963 (405/Occlusal-Onlay-Standard), 1108 (340/Occlusal-Onlay-Thin), 997 (331/Occlusal-Onlay-Ultra-Thin), 1361 (333/Complete-Veneer-Standard), 1087 (251/Complete-Veneer-Thin), 883 (311/Complete

  15. Design optimization of scaffold microstructures using wall shear stress criterion towards regulated flow-induced erosion.

    PubMed

    Chen, Yuhang; Schellekens, Michiel; Zhou, Shiwei; Cadman, Joseph; Li, Wei; Appleyard, Richard; Li, Qing

    2011-08-01

    Tissue scaffolds aim to provide a cell-friendly biomechanical environment for facilitating cell growth. Existing studies have shown significant demands for generating a certain level of wall shear stress (WSS) on scaffold microstructural surfaces for promoting cellular response and attachment efficacy. Recently, its role in shear-induced erosion of polymer scaffold has also drawn increasing attention. This paper proposes a bi-directional evolutionary structural optimization (BESO) approach for design of scaffold microstructure in terms of the WSS uniformity criterion, by downgrading highly-stressed solid elements into fluidic elements and/or upgrading lowly-stressed fluidic elements into solid elements. In addition to this, a computational model is presented to simulate shear-induced erosion process. The effective stiffness and permeability of initial and optimized scaffold microstructures are characterized by the finite element based homogenization technique to quantify the variations of mechanical properties of scaffold during erosion. The illustrative examples show that a uniform WSS is achieved within the optimized scaffold microstructures, and their architectural and biomechanical features are maintained for a longer lifetime during shear-induced erosion process. This study provides a mathematical means to the design optimization of cellular biomaterials in terms of the WSS criterion towards controllable shear-induced erosion.

  16. Functionalized Single-Walled Carbon Nanotubes as Rationally Designed Vehicles for Tumor-Targeted Drug Delivery

    SciTech Connect

    Chen,J.; Wong,S.; Chen, S.; Zhao, X.; Kuznetsova, L.V.; and Ojima, I.

    2008-11-14

    A novel single-walled carbon nanotube (SWNT)-based tumor-targeted drug delivery system (DDS) has been developed, which consists of a functionalized SWNT linked to tumor-targeting modules as well as prodrug modules. There are three key features of this nanoscale DDS: (a) use of functionalized SWNTs as a biocompatible platform for the delivery of therapeutic drugs or diagnostics, (b) conjugation of prodrug modules of an anticancer agent (taxoid with a cleavable linker) that is activated to its cytotoxic form inside the tumor cells upon internalization and in situ drug release, and (c) attachment of tumor-recognition modules (biotin and a spacer) to the nanotube surface. To prove the efficacy of this DDS, three fluorescent and fluorogenic molecular probes were designed, synthesized, characterized, and subjected to the analysis of the receptor-mediated endocytosis and drug release inside the cancer cells (L1210FR leukemia cell line) by means of confocal fluorescence microscopy. The specificity and cytotoxicity of the conjugate have also been assessed and compared with L1210 and human noncancerous cell lines. Then, it has unambiguously been proven that this tumor-targeting DDS works exactly as designed and shows high potency toward specific cancer cell lines, thereby forming a solid foundation for further development.

  17. Effect of open-label infusion of an apoA-I-containing particle (CER-001) on RCT and artery wall thickness in patients with FHA.

    PubMed

    Kootte, Ruud S; Smits, Loek P; van der Valk, Fleur M; Dasseux, Jean-Louis; Keyserling, Constance H; Barbaras, Ronald; Paolini, John F; Santos, Raul D; van Dijk, Theo H; Dallinga-van Thie, Geesje M; Nederveen, Aart J; Mulder, Willem J M; Hovingh, G Kees; Kastelein, John J P; Groen, Albert K; Stroes, Erik S

    2015-03-01

    Reverse cholesterol transport (RCT) contributes to the anti-atherogenic effects of HDL. Patients with the orphan disease, familial hypoalphalipoproteinemia (FHA), are characterized by decreased tissue cholesterol removal and an increased atherogenic burden. We performed an open-label uncontrolled proof-of-concept study to evaluate the effect of infusions with a human apoA-I-containing HDL-mimetic particle (CER-001) on RCT and the arterial vessel wall in FHA. Subjects received 20 infusions of CER-001 (8 mg/kg) during 6 months. Efficacy was assessed by measuring (apo)lipoproteins, plasma-mediated cellular cholesterol efflux, fecal sterol excretion (FSE), and carotid artery wall dimension by MRI and artery wall inflammation by (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography scans. We included seven FHA patients: HDL-cholesterol (HDL-c), 13.8 [1.8-29.1] mg/dl; apoA-I, 28.7 [7.9-59.1] mg/dl. Following nine infusions in 1 month, apoA-I and HDL-c increased directly after infusion by 27.0 and 16.1 mg/dl (P = 0.018). CER-001 induced a 44% relative increase (P = 0.018) in in vitro cellular cholesterol efflux with a trend toward increased FSE (P = 0.068). After nine infusions of CER-001, carotid mean vessel wall area decreased compared with baseline from 25.0 to 22.8 mm(2) (P = 0.043) and target-to-background ratio from 2.04 to 1.81 (P = 0.046). In FHA-subjects, CER-001 stimulates cholesterol mobilization and reduces artery wall dimension and inflammation, supporting further evaluation of CER-001 in FHA patients. Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.

  18. Effect of open-label infusion of an apoA-I-containing particle (CER-001) on RCT and artery wall thickness in patients with FHA[S

    PubMed Central

    Kootte, Ruud S.; Smits, Loek P.; van der Valk, Fleur M.; Dasseux, Jean-Louis; Keyserling, Constance H.; Barbaras, Ronald; Paolini, John F.; Santos, Raul D.; van Dijk, Theo H.; Dallinga-van Thie, Geesje M.; Nederveen, Aart J.; Mulder, Willem J. M.; Hovingh, G. Kees; Kastelein, John J. P.; Groen, Albert K.; Stroes, Erik S.

    2015-01-01

    Reverse cholesterol transport (RCT) contributes to the anti-atherogenic effects of HDL. Patients with the orphan disease, familial hypoalphalipoproteinemia (FHA), are characterized by decreased tissue cholesterol removal and an increased atherogenic burden. We performed an open-label uncontrolled proof-of-concept study to evaluate the effect of infusions with a human apoA-I-containing HDL-mimetic particle (CER-001) on RCT and the arterial vessel wall in FHA. Subjects received 20 infusions of CER-001 (8 mg/kg) during 6 months. Efficacy was assessed by measuring (apo)lipoproteins, plasma-mediated cellular cholesterol efflux, fecal sterol excretion (FSE), and carotid artery wall dimension by MRI and artery wall inflammation by 18F-fluorodeoxyglucose-positron emission tomography/computed tomography scans. We included seven FHA patients: HDL-cholesterol (HDL-c), 13.8 [1.8–29.1] mg/dl; apoA-I, 28.7 [7.9–59.1] mg/dl. Following nine infusions in 1 month, apoA-I and HDL-c increased directly after infusion by 27.0 and 16.1 mg/dl (P = 0.018). CER-001 induced a 44% relative increase (P = 0.018) in in vitro cellular cholesterol efflux with a trend toward increased FSE (P = 0.068). After nine infusions of CER-001, carotid mean vessel wall area decreased compared with baseline from 25.0 to 22.8 mm2 (P = 0.043) and target-to-background ratio from 2.04 to 1.81 (P = 0.046). In FHA-subjects, CER-001 stimulates cholesterol mobilization and reduces artery wall dimension and inflammation, supporting further evaluation of CER-001 in FHA patients. PMID:25561459

  19. Wall surveyor project report

    SciTech Connect

    Mullenhoff, D.J.; Johnston, B.C.; Azevedo, S.G.

    1996-02-22

    A report is made on the demonstration of a first-generation Wall Surveyor that is capable of surveying the interior and thickness of a stone, brick, or cement wall. LLNL`s Micropower Impulse Radar is used, based on emitting and detecting very low amplitude and short microwave impulses (MIR rangefinder). Six test walls were used. While the demonstrator MIR Wall Surveyor is not fieldable yet, it has successfully scanned the test walls and produced real-time images identifying the walls. It is planned to optimize and package the evaluation wall surveyor into a hand held unit.

  20. Simulation-based design optimization and control of thick composite laminates manufactured by resin transfer molding

    NASA Astrophysics Data System (ADS)

    Michaud, Dennis J.

    2000-10-01

    Processing thick-sectioned composites (>1/2″ ) can be difficult due to the exothermic nature of the resin and the low thermal conductivity of the composite. This is particularly true for the Resin Transfer Molding process examined here. The temperature profile used to polymerize the resin, otherwise known as a "cure cycle," must be carefully chosen to reduce thermal gradients within the composite while ensuring satisfactory processing times. Instead of trial and error methods that are expensive, time consuming, and non-optimal, we propose a knowledge-based optimization strategy. In order to be effective, the optimization strategy requires an accurate simulation of the process and supplementary heuristic information. A 1-D finite difference cure simulation was used to simulate the process. Some of the simulation's model input parameters were found directly through experimentation. Other input parameters were identified using a least-squares approach to match the simulation to experimental data from seven test composites. Because an accurate residual stress model for the process was unavailable, a heuristic for predicting the quality of a composite, based on the progression of resin cure within the composite, was used. Four different global optimization schemes were studied: Random Walk, Simulated Annealing, Genetic Algorithms, and Evolutionary Strategies. The optimal cure cycle suggests heating the composite to initiate cure followed by a cooling stage to ensure inside-out curing. An extension of the Evolutionary Strategies optimization method was developed to account for the known variability in the simulation's input parameters and generate an optimum that can withstand some batch to batch variations. In addition to the suggested cure cycle, we propose to implement adaptive control. Through a sensitivity analysis of the optimal cure cycle, the conditions and manner of altering the cure cycle were identified. Furthermore, instead of relying on intrusive sensors

  1. Design and development of multi-walled carbon nanotube-liposome drug delivery platforms.

    PubMed

    Pippa, Natassa; Chronopoulos, Demetrios D; Stellas, Dimitris; Fernández-Pacheco, Rodrigo; Arenal, Raul; Demetzos, Costas; Tagmatarchis, Nikos

    2017-08-07

    The aim of this study is to design and develop delivery platforms made of liposomes and multi-walled carbon nanotubes (MWCNTs). We used different lipids with different main transition temperature (Tm) and differently functionalized MWCNTs with organic addends possessing either positive or negative charge. The phospholipids used for the formulations were 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) (Tm=41°C) and L-α-phosphatidylcholine, hydrogenated Soy (HSPC) (Tm=53°C). By Differential Scanning Calorimetry (DSC), we studied the interaction between the DPPC and HSPC bilayers and MWCNTs. Liposome-MWCNTs delivery platforms prepared according to the protocol used in the literature. We used dynamic and electrophoretic light scattering in order to investigate the physicochemical characteristics of these mixed nanocarriers. The presence of MWCNTs causes alterations of the size of the conventional HSPC and DPPC liposomes. The ζ-potential values of mixed nanocarriers are near zero. This observation indicates the effective incorporation of MWCNTs into the lipid bilayer of liposomes. Fluorescence spectroscopy has been utilized to exact some qualitative information on the internal nanostructure and nanoenvironment of the lipid/carbon nanotube mixed structures. Finally, we conclude that we successfully prepare and completely characterize mixed nanocarriers composed of lipids and MWCNTs, with low toxicity as indicated by in vitro screening. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Multiple factor design for reactive mixture selection for use in reactive walls in mine drainage treatment.

    PubMed

    Cocos, Ioana A; Zagury, Gerald J; Clément, Bernard; Samson, Réjean

    2002-01-01

    Sulfate-reducing reactive walls installed in situ in the path of acid mine drainage contaminated groundwater, present a promising passive treatment technology. However, a rigorous and methodical selection of the most appropriate reactive mixture composition still needs to be investigated. The aim of this study was the selection of the most reactive medium using a multiple factor design and the modeling of the sulfate-reduction rate. Reactivity of 17 mixtures was assessed in batch reactors (in duplicates) using a synthetic AMD. Results indicate that within 41 days, sulfate concentrations decreased from initial concentrations of 2,000-3,200 mg/l to final concentrations of <90 mg/l. Metal removal efficiencies ranged between 51-84% for Ni and 73-93% for Zn. Generated sulfate-reduction rate predictive models which had very satisfactory parameters (R2 = 0.86, F = 62.38 (p-level < 10(-13)) and R2 = 0.90. F = 62.30 (p-level < 10(-13))) identified poultry manure and two other carbon sources as the critical variables for sulfate-reduction rate.

  3. GeoWall: Stereo Projection Systems Designed for Earth Science Classrooms

    NASA Astrophysics Data System (ADS)

    Morin, P.; Kirkby, K. C.; Van Keken, P.; Leigh, J.; Reynolds, S. J.; Davis, B.; Burdick, R.; Schumann, L.

    2001-12-01

    Within the past year, advances in projection technology and consumer-grade computer game technology have reduced the cost of stereo projection systems to a level that allows this technology to be used in the classroom. Stereo projection systems have remarkable potential for any educational discipline that deals with complex spatial relationships (engineering, physics, astronomy, etc.), but the implications for earth science education are particularly rich. The ability to visualize and interpret spatial relationships is a critical skill that many earth science students find difficult to master. Stereo projection can serve as a bridge to increase students' perception of maps, images and aerial views, or allow students to interactively manipulate three-dimensional, time-dependent visualizations of research data sets and mathematical models that move well beyond traditional education materials. The GeoWall Project is an initiative to build low-cost, high-quality stereo projection systems at a number of research and education institutions. By standardizing the technical design of these systems, materials developed by one institution can be used by any of the other member institutions. This allows institutions to easily adopt materials that they could not produce in-house and fosters a community capable of generating curriculum materials that take advantage of stereo projection technology. Although not universally applicable across earth science education, stereo projection systems have the potential to transform the way that we teach many earth science concepts.

  4. Modifying the electronic properties of single-walled carbon nanotubes using designed surfactant peptides

    NASA Astrophysics Data System (ADS)

    Samarajeewa, Dinushi R.; Dieckmann, Gregg R.; Nielsen, Steven O.; Musselman, Inga H.

    2012-07-01

    The electronic properties of carbon nanotubes can be altered significantly by modifying the nanotube surface. In this study, single-walled carbon nanotubes (SWCNTs) were functionalized noncovalently using designed surfactant peptides, and the resultant SWCNT electronic properties were investigated. These peptides have a common amino acid sequence of X(Valine)5(Lysine)2, where X indicates an aromatic amino acid containing either an electron-donating or electron-withdrawing functional group (i.e. p-amino-phenylalanine or p-cyano-phenylalanine). Circular dichroism spectra showed that the surfactant peptides primarily have random coil structures in an aqueous medium, both alone and in the presence of SWCNTs, simplifying analysis of the peptide/SWCNT interaction. The ability of the surfactant peptides to disperse individual SWCNTs in solution was verified using atomic force microscopy and ultraviolet-visible-near-infrared spectroscopy. The electronic properties of the surfactant peptide/SWCNT composites were examined using the observed nanotube Raman tangential band shifts and the observed additional features near the Fermi level in the scanning tunneling spectroscopy dI/dV spectra. The results revealed that SWCNTs functionalized with surfactant peptides containing electron-donor or electron-acceptor functional groups showed n-doped or p-doped altered electronic properties, respectively. This work unveils a facile and versatile approach to modify the intrinsic electronic properties of SWCNTs using a simple peptide structure, which is easily adaptable to obtain peptide/SWCNT composites for the design of tunable nanoscale electronic devices.The electronic properties of carbon nanotubes can be altered significantly by modifying the nanotube surface. In this study, single-walled carbon nanotubes (SWCNTs) were functionalized noncovalently using designed surfactant peptides, and the resultant SWCNT electronic properties were investigated. These peptides have a common amino

  5. Aerodynamic Characteristics of a 14-Percent-Thick NASA Supercritical Airfoil Designed for a Normal-Force Coefficient of 0.7

    NASA Technical Reports Server (NTRS)

    Harris, C. D.

    1975-01-01

    This report documents the experimental aerodynamic characteristics of a 14 percent thick supercritical airfoil based on an off design sonic pressure plateau criterion. The design normal force coefficient was 0.7. The results are compared with those of the family related 10 percent thick supercritical airfoil 33. Comparisons are also made between experimental and theoretical characteristics and composite drag rise characteristics derived for a full scale Reynolds number of 40 million.

  6. Continuous Processing of Multi-Walled Carbon Nanotube-Studded Carbon Fiber Tapes for Enhanced Through-Thickness Thermal Diffusivity Composites.

    PubMed

    Craddock, John D; Qian, Dali; Lester, Catherine; Matthews, JohnJ; Mansfield, J Patrick W; Foedinger, Richard; Weisenberger, Matthew C

    2015-09-01

    Carbon fiber reinforced polymer (CFRP) composites offer advantages over traditional metallic structures, particularly specific strength and stiffness, but at much reduced thermal conductivity. Moreover, fiber-to-fiber heat conduction in the composite transverse directions is significantly lower. When these structures contain electronics (heat generators), shortfalls in heat transport can be problematic. Here we report the achievement of a continuous, reel-to-reel process for growing short multiwalled carbon nanotubes (MWCNT) on the surfaces of spread-tow carbon fiber tapes. These tapes were subsequently prepregged with an epoxy matrix, and laid up into multi-ply laminate panels, cured and tested for through-thickness thermal diffusivity. The results showed up to a 57% increase in through thickness thermal diffusivity compared to the baseline composite with no MWCNT.

  7. Design of the shielding wall of a cyclotron room and the activation interpretation using the Monte Carlo simulation