Science.gov

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, 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.

  3. 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.

  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. Wall thickness measuring method and apparatus

    DOEpatents

    Salzer, L.J.; Bergren, D.A.

    1987-10-06

    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.

  6. 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.

  7. 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.

  8. 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.

  9. High accuracy wall thickness loss monitoring

    NASA Astrophysics Data System (ADS)

    Gajdacsi, Attila; Cegla, Frederic

    2014-02-01

    Ultrasonic inspection of wall thickness in pipes is a standard technique applied widely in the petrochemical industry. The potential precision of repeat measurements with permanently installed ultrasonic sensors however significantly surpasses that of handheld sensors as uncertainties associated with coupling fluids and positional offsets are eliminated. With permanently installed sensors the precise evaluation of very small wall loss rates becomes feasible in a matter of hours. The improved accuracy and speed of wall loss rate measurements can be used to evaluate and develop more effective mitigation strategies. This paper presents an overview of factors causing variability in the ultrasonic measurements which are then systematically addressed and an experimental setup with the best achievable stability based on these considerations is presented. In the experimental setup galvanic corrosion is used to induce predictable and very small wall thickness loss. Furthermore, it is shown that the experimental measurements can be used to assess the effect of reduced wall loss that is produced by the injection of corrosion inhibitor. The measurements show an estimated standard deviation of about 20nm, which in turn allows us to evaluate the effect and behaviour of corrosion inhibitors within less than an hour.

  10. 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.

  11. 49 CFR 178.33-7 - Wall thickness.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Wall thickness. 178.33-7 Section 178.33-7 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers, and Linings § 178.33-7 Wall thickness. (a) The minimum wall thickness for any container shall...

  12. 49 CFR 178.33-7 - Wall thickness.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Wall thickness. 178.33-7 Section 178.33-7 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Specifications for Inside Containers, and Linings § 178.33-7 Wall thickness. (a) The minimum wall thickness...

  13. 49 CFR 178.33-7 - Wall thickness.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Wall thickness. 178.33-7 Section 178.33-7 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers, and Linings § 178.33-7 Wall thickness. (a) The minimum wall thickness for any container shall...

  14. 49 CFR 178.33a-7 - Wall thickness.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Wall thickness. 178.33a-7 Section 178.33a-7 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers, and Linings § 178.33a-7 Wall thickness. (a) The minimum wall thickness for any container shall...

  15. 49 CFR 178.33a-7 - Wall thickness.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Wall thickness. 178.33a-7 Section 178.33a-7 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers, and Linings § 178.33a-7 Wall thickness. (a) The minimum wall thickness for any container shall...

  16. 49 CFR 178.33-7 - Wall thickness.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Wall thickness. 178.33-7 Section 178.33-7 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers, and Linings § 178.33-7 Wall thickness. (a) The minimum wall thickness for any container shall...

  17. 49 CFR 178.33-7 - Wall thickness.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Wall thickness. 178.33-7 Section 178.33-7 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers, and Linings § 178.33-7 Wall thickness. (a) The minimum wall thickness for any container shall...

  18. 49 CFR 178.33a-7 - Wall thickness.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Wall thickness. 178.33a-7 Section 178.33a-7 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Specifications for Inside Containers, and Linings § 178.33a-7 Wall thickness. (a) The minimum wall thickness...

  19. 49 CFR 178.33a-7 - Wall thickness.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Wall thickness. 178.33a-7 Section 178.33a-7 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers, and Linings § 178.33a-7 Wall thickness. (a) The minimum wall thickness for any container shall...

  20. 49 CFR 178.33a-7 - Wall thickness.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Wall thickness. 178.33a-7 Section 178.33a-7 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers, and Linings § 178.33a-7 Wall thickness. (a) The minimum wall thickness for any container shall...

  1. Gastric Wall Thickness in Sleeve Gastrectomy Patients: Thickness Variation of the Gastric Wall.

    PubMed

    van Rutte, Pim W J; Naagen, Bertus J; Spek, Marinus; Jakimowicz, Jack J; Nienhuijs, Simon W

    2015-11-01

    The sleeve gastrectomy has been accepted as a primary bariatric procedure. One of the most feared complications is staple line leakage. It is important to use the right staple sizes to minimize the risk of leak. Knowledge of gastric thickness is important. The goal of this study was to measure the thickness of the gastric wall after elimination of the gastric folds in the mucosa. An electronic thickness gauge was developed that measured the anterior and posterior wall of the fresh stomach specimen together at 5 points at a pressure based on the finger pressure necessary to flatten the gastric folds. Thirty-three fresh specimens were measured. The mean compression pressure was 714 grams, and no difference was found between the 5 measure points. There was a significant difference in stomach wall thickness. The gastric antrum was more than 1 mm thicker than the fundus. No difference was found between BMI groups <40 Kg/m2, 40-50 Kg/m2, or >50 Kg/m2. No bleeding occurred, leakage occurred in 1 case. There is a significant difference in thickness of the stomach wall between the gastric fundus and the antrum. A pressure 2.5 times lower than applied in prior studies was necessary to achieve full tissue compression. Choosing thinner staple sizes for the gastric fundus might be the optimal technique for compression. However, there are several additional factors that influence the risk of staple line leaks. PMID:26680415

  2. 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.

  3. New portable pipe wall thickness measuring technique

    NASA Astrophysics Data System (ADS)

    Pascente, Joseph E.

    1998-03-01

    One of the biggest inspection challenges facing many of the process industries; namely the petrochemical, refining, fossil power, and pulp and paper industries is: How to effectively examine their insulated piping? While there are a number of failure mechanisms involved in various process piping systems, piping degradation through corrosion and erosion are by far the most prevalent. This degradation can be in the form of external corrosion under insulation, internal corrosion through a variety of mechanisms, and internal erosion caused by the flow of the product through the pipe. Refineries, chemical plants and electrical power plants have MANY thousands of miles of pipe that are insulated to prevent heat loss or heat absorption. This insulation is often made up of several materials, with calcium based material being the most dense. The insulating material is usually wrapped with an aluminum or stainless steel outer wrap. Verification of wall thickness of these pipes can be accomplished by removing the insulation and doing an ultrasound inspection or by taking x- rays at a tangent to the edge of the pipe through the insulation. Both of these processes are slow and expensive. The time required to obtain data is measured in hours per meter. The ultrasound method requires that the insulation be plugged after the inspection. The surface needs to be cleaned or the resulting data will not be accurate. The tangent x-ray only shows two thicknesses and requires that the area be roped off because of radiation safety.

  4. 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.

  5. 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.

  6. 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.

  7. Reconstruction of full thickness chest wall defects.

    PubMed Central

    Morgan, R F; Edgerton, M T; Wanebo, H J; Daniel, T M; Spotnitz, W D; Kron, I L

    1988-01-01

    Over the last 5 years, 14 patients were treated by wide en bloc resection of chest wall tumors with primary reconstruction. There were nine females and five male patients with an age range of 31-77 years. All patients had a skeletal resection of the chest wall. An average of 3.9 ribs were resected in the patients treated. In three patients a partial sternectomy was carried out in conjunction with the rib resections. Chest wall skeletal defects were reconstructed with Prolene mesh, which was placed under tension. Soft tissue reconstruction utilized selected portions of the latissimus dorsi musculocutaneous territory with fasciocutaneous extensions beyond the muscle itself. Primary healing was obtained in all patients and secondary procedures were not required. The average hospitalization was 23 days. All patients survived the resection and reconstruction and were alive 30 days after operation. In selected patients the preservation of a portion of the innervated muscle in situ or the transfer of the muscle with the preservation of its resting length has maintained the majority of the muscle function. Images Fig. 3A. Fig. 3C. Fig. 3D. Fig. 4A. Fig. 4C. Fig. 4D. Fig. 4E. Fig. 5A. Fig. 5B. Fig. 5D. Fig. 6A. Fig. 6C. Fig. 6D. Fig. 6E. Fig. 6F. Fig. 6G. Fig. 6H. PMID:3389939

  8. Reconstruction of full thickness chest wall defects.

    PubMed

    Morgan, R F; Edgerton, M T; Wanebo, H J; Daniel, T M; Spotnitz, W D; Kron, I L

    1988-06-01

    Over the last 5 years, 14 patients were treated by wide en bloc resection of chest wall tumors with primary reconstruction. There were nine females and five male patients with an age range of 31-77 years. All patients had a skeletal resection of the chest wall. An average of 3.9 ribs were resected in the patients treated. In three patients a partial sternectomy was carried out in conjunction with the rib resections. Chest wall skeletal defects were reconstructed with Prolene mesh, which was placed under tension. Soft tissue reconstruction utilized selected portions of the latissimus dorsi musculocutaneous territory with fasciocutaneous extensions beyond the muscle itself. Primary healing was obtained in all patients and secondary procedures were not required. The average hospitalization was 23 days. All patients survived the resection and reconstruction and were alive 30 days after operation. In selected patients the preservation of a portion of the innervated muscle in situ or the transfer of the muscle with the preservation of its resting length has maintained the majority of the muscle function. PMID:3389939

  9. 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.

  10. An analytic description of thick-wall bubbles

    SciTech Connect

    Hong, Jooyoo.

    1992-01-01

    A new approximation scheme to the false-vacuum decay is suggested. In this scheme the bounce solutions can be obtained in an explicit and analytic way even for thick-wall bubbles. The result is compared with Coleman's thin-wall description, which shows that is nicely comprises the result of the latter prescription. Some applications are also discussed.

  11. An analytic description of thick-wall bubbles

    SciTech Connect

    Hong, Jooyoo

    1992-08-01

    A new approximation scheme to the false-vacuum decay is suggested. In this scheme the bounce solutions can be obtained in an explicit and analytic way even for thick-wall bubbles. The result is compared with Coleman`s thin-wall description, which shows that is nicely comprises the result of the latter prescription. Some applications are also discussed.

  12. 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

  13. Strain to failure of pressurized thick wall cylinders

    SciTech Connect

    Priddy, T.G.; Roach, D.P.

    1989-01-01

    The determination of the fully plastic response and pressure limit of a highly pressurized vessel is of considerable importance in design. The plastic-strain response during and following autofrettage operations, in comparison with the limiting strain condition, is of special interest. This paper presents the results of an analysis method for thick wall, high pressure, cylinders where the effective plastic strain distribution through the thickness is the material response variable of primary interest. The limiting value of this effective plastic strain depends on the level of tensile-stress triaxiality which also varies through the thickness. This strain-to-failure criterion is used to predict the complete pressure versus strain response and the maximum pressure for test cylinders. A simple model of effective-stress versus effective plastic strain is employed. This model is quantified by data taken from uniaxial, tension, true-stress-strain curves and from the fracture zone of the tensile specimen. A sample calculation is included and, in a companion paper, a series of burst tubes having properties ranging from brittle to ductile are compared with this analytical method. 21 refs., 5 figs., 2 tabs.

  14. 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.

  15. 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

  16. 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.

  17. Vesicular thick-walled swollen hyphae in pulmonary zygomycosis.

    PubMed

    Kimura, Masatomo; Ito, Hiroyuki

    2009-03-01

    An autopsy case of pulmonary zygomycosis in a patient with rheumatoid arthritis on immunosuppressive therapy is presented herein. There was a pulmonary cavitated infarct caused by mycotic thrombosis. Thin-walled narrow hyphae and vesicular thick-walled swollen hyphae were found on the pleural surface and in the necrotic tissue at the periphery of the cavity. Findings of such shaped fungal elements may cause erroneous histopathological diagnosis because pauciseptate broad thin-walled hyphae are usually the only detectable fungal elements in zygomycosis tissue. Although immunohistochemistry confirmed these unusual elements to be zygomycetous in the present case, it is important for the differential diagnosis to be aware that zygomycetes can form thin narrow hyphae and vesicular thick-walled swollen hyphae. PMID:19261095

  18. 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.

  19. 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.

  20. 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.

  1. 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. PMID:26356964

  2. Performance Evaluation of Several Types of Pulsed Eddy Current Probes for Detecting Wall Thickness Reduction

    NASA Astrophysics Data System (ADS)

    Shin, Young-Kil; Choi, Dong-Myung; Jung, Hee-Sung; Um, Tae-Gun

    2010-02-01

    In this paper, four different types of pulsed eddy current (PEC) probe are designed and their performance of detecting wall thickness reduction is compared. By using the backward difference method in time and the finite element method in space, PEC signals from various thickness and materials are numerically calculated and three features of the signal are selected. Since PEC signals and features are obtained by various types and sizes of probe, the comparison is made through the normalized features which reflect the sensitivity of the feature to thickness reduction. The normalized features indicate that the shielded reflection probe provides the best sensitivity to wall thickness reduction for all three signal features. Results show that the best sensitivity to thickness reduction is achieved by the peak value, but also suggest that the time to peak can be a good candidate because of its linear relationship with the thickness variation.

  3. 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.

  4. 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.

  5. Thick-wall effects in the theory of resistive wall modes

    SciTech Connect

    Pustovitov, V. D.

    2012-06-15

    Magnetic interaction of the plasma perturbations with the nearby resistive wall is considered as a resistive wall mode (RWM) problem, but with two essential differences from the traditional thin-wall approach. First, the wall is treated as magnetically thick, which means that the skin depth is not assumed larger than the wall thickness. Second, the plasma is allowed to enter the region where the RWM must be deeply unstable without rotation. The latter corresponds to the plasma operation above the no-wall stability limit demonstrated in the DIII-D tokamak [E. J. Strait et al., Phys. Plasmas 11, 2505 (2004)]. It is shown that the rotational stabilization observed in these experiments can be reproduced in this model if the mode is forced to rotate with a frequency above a critical level. The analytical estimates show that this effect (absent in the model based on the thin-wall approximation) is strong at realistic parameters. The model also predicts that the locking of the rotationally stabilized mode gives rise to instability with a growth rate much larger than its thin-wall estimate.

  6. Eddy current technique applied to the nondestructive evaluation of turbine blade wall thickness

    NASA Astrophysics Data System (ADS)

    Le Bihan, Yann; Joubert, Pierre-Yves; Placko, Dominique

    2000-05-01

    The high pressure turbine blades of jet engines show internal channels designed for air cooling. These recesses define the internal walls (partitions) and external walls of the blade. The external wall thickness is a critical parameter which has to be systematically checked in order to ensure the blade strength. The thickness evaluation is usually lead by ultrasonic technique or by X-ray tomography. Nevertheless, both techniques present some drawbacks related to measurement speed and automation capability. These drawbacks are bypassed by the eddy current (EC) technique, well known for its robustness and reliability. However, the wall thickness evaluation is made difficult because of the complexity of the blade geometry. In particular, some disturbances appear in the thickness evaluation because of the partitions, which exclude the use of classical EC probes such as cup-core probe. In this paper, we show the main advantages of probes creating an uniformly oriented magnetic field in order to reduce the partition disturbances. Furthermore, we propose a measurement process allowing to separate the wall thickness parameter from the EC signals. Finally, we present some experimental results validating the proposed technique.

  7. Theoretical quantification of the effects of plastic wall thickness on phantom measurements in electromagnetic hyperthermia.

    PubMed

    Ross, M P; Paulsen, K D

    1989-08-01

    Phantom experiments are a staple of research and development in electromagnetic hyperthermia. Phantom containers and compartments are typically constructed from plastics which are readily available in a wide variety of thicknesses and material compositions. The perturbation effects of these plastics on the electric fields to be measured may be important, especially if one is trying to obtain quantitative results such as when comparing with a numerical model. This communication presents a theoretical investigation into the effects of plastic wall thickness on the computed electric field. Design curves are reported which aid in the selecting of an acceptable wall thickness given a maximum degree of wall perturbation that can be tolerated. Many other materials such as rubbers and polystyrenes also have electrical properties within the ranges considered herein; hence, the results should apply to a variety of commonly used phantom construction materials. PMID:2759648

  8. Inverse Design of a Thick Supercritical Airfoil

    NASA Astrophysics Data System (ADS)

    Pambagjo, Tjoetjoek Eko; Nakahashi, Kazuhiro; Obayashi, Shigeru

    In this paper, a study on designing a thick supercritical airfoil by utilizing Takanashi’s inverse design method is discussed. One of the problems to design a thick supercritical airfoil by Takanashi’s method is that an oscillation of the geometry may occur during the iteration process. To reduce the oscillation, an airfoil parameterization method is utilized as the smoothing procedure. A guideline to determine the target pressure distribution to realize the thick airfoil is also discussed.

  9. Microvascular Reconstructions of Full-Thickness Oncological Chest Wall Defects

    PubMed Central

    Tukiainen, Erkki; Popov, Pentscho; Asko-Seljavaara, Sirpa

    2003-01-01

    Objective: To evaluate the suitability of microvascular flaps for the reconstruction of extensive full-thickness defects of the chest wall. Summary Background Data: Chest wall defects are conventionally reconstructed with pedicular musculocutaneous flaps or the omentum. Sometimes, however, these flaps have already been used, are not reliable due to previous operations or radiotherapy, or are of inadequate size. In such cases, microvascular flaps offer the only option for reconstruction. Methods: From 1988 to 2001, 26 patients with full-thickness resections of the chest wall underwent reconstruction with microvascular flaps. There were 8 soft tissue sarcomas, 8 recurrent breast cancers, 5 chondrosarcomas, 2 desmoid tumors, 1 large cell pulmonary cancer metastasis, 1 renal cancer metastasis, and 1 bronchopleural fistula. The surgery comprised 5 extended forequarter amputations, 5 lateral resections, 8 thoracoabdominal resections, and 8 sternal resections. The mean diameter of a resection was 28 cm. The soft tissue defect was reconstructed with 16 tensor fasciae latae, 5 tensor fascia latae combined with rectus femoris, and 3 transversus rectus abdominis myocutaneous flaps. In 2 patients with a forequarter amputation, the remnant forearm was used as the osteomusculocutaneous free flap. Results: There were no flap losses or perioperative mortality. Four patients needed tracheostomy owing to prolonged respiratory difficulties. The mean survival time for patients with sarcomas was 39 months and for those with recurrent breast cancer 18 months. Conclusions: Extensive chest wall resections are possible with acceptable results. In patients with breast cancer, the surgery may offer valuable palliation and in those with sarcomas it can be curative. PMID:14631216

  10. Thick-walled composite tubes under mechanical and hygrothermal loading

    NASA Astrophysics Data System (ADS)

    Wuetrich, C.

    1992-11-01

    The stresses in long thick-walled composite tubes were determined analytically for loading by internal and external pressure, longitudinal forces and twisting moments. Effects of thermal and hygrothermal expansion were also treated. The solution is restricted to tubes built up from one or more layers with macroscopically orthotropic properties. Such layers may be produced, for example, by filament winding or winding of textile reinforcements. It was shown how the elastic and hygrothermal parameters of the macroscopically orthotropic materials may be calculated by homogenization of the properties of uniaxially reinforced materials.

  11. 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.

  12. 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.

  13. 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. PMID:26803337

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  20. 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.

  1. Changes in Bladder Wall Thickness and Detrusor Wall Thickness After Surgical Treatment of Benign Prostatic Enlargement in Patients With Lower Urinary Tract Symptoms: A Preliminary Report

    PubMed Central

    Lee, Hakmin; Choo, Minsoo; Kim, Myong; Cho, Sung Yong; Lee, Seung Bae; Jeong, Hyeon

    2014-01-01

    Purpose The purpose of the present study was to evaluate the perioperative changes in bladder wall thickness and detrusor wall thickness after transurethral prostatectomy. Materials and Methods Fifty-one men who were treated for benign prostatic hyperplasia/lower urinary tract symptoms with transurethral prostatectomy were prospectively analyzed from May 2012 to July 2013. Prostate size, detrusor wall thickness, and bladder wall thickness were assessed by transrectal and transabdominal ultrasonography perioperatively. All postoperative evaluations were performed 1 month after the surgery. Results The patients' mean age was 69.0 years, the mean prostate-specific antigen concentration was 8.1 ng/mL, and the mean prostate volume was 63.2 mL. The mean bladder wall thickness was 5.1 mm (standard deviation [SD], ±1.6), 5.1 mm (SD, ±1.6), and 5.0 mm (SD, ±1.4) preoperatively and 4.5 mm (SD, ±1.5), 4.5 mm (SD, ±1.3), and 4.6 mm (SD, ±1.2) postoperatively in the anterior wall, dome, and trigone, respectively (p=0.178, p=0.086, and p=0.339, respectively). The mean detrusor wall thickness was 0.9 mm (SD, ±0.4) preoperatively and 0.7 mm (SD, ±0.3) postoperatively (p=0.001). A subgroup analysis stratifying patients into a large prostate group (weight, ≥45 g) and a high Abrams-Griffiths number group (>30) showed a significant decrease in detrusor wall thickness (p=0.002, p=0.018). Conclusions There was a decrease in detrusor wall thickness after transurethral prostatectomy. The large prostate group and the high Abrams-Griffiths number group showed a significant decrease in detrusor wall thickness after surgery. PMID:24466397

  2. Thick Liquid-Walled Spheromak Magnetic Fusion Power Plant

    SciTech Connect

    Moir, R W; Bulmer, R H; Fowler, T K; Youssef, M Z

    2002-04-08

    We assume a spheromak configuration can be made and sustained by a steady gun current, which injects particles, current and magnetic field, i.e., helicity injection. The equilibrium is calculated with an MHD equilibrium code, where an average beta of 10% is found. The toroidal current of 40 MA is sustained by an injection current of 100 kA (125 MW of gun power). The flux linking the gun is 1/1000th that of the flux in the spheromak. The geometry allows a flow of liquid, either molten salt, (flibe-Li{sub 2}BeF{sub 4} or flinabe-LiNaBeF{sub 4}) or liquid metal such as SnLi which protects most of the walls and structures from neutron damage. The free surface between the liquid and the burning plasma is heated by bremsstrahlung and optical radiation and neutrons from the plasma. The temperature of the free surface of the liquid is calculated and then the evaporation rate is estimated. The impurity concentration in the burning plasma is estimated and limited to a 20% reduction in the fusion power. For a high radiating edge plasma, the divertor power density of 460 MW/m{sup 2} is handled by high-speed (20 m/s), liquid jets. For low radiating edge plasmas, the divertor-power density of 1860 MW/m{sup 2} is too high to handle for flibe but possibly acceptable for SnLi with jets of 100 m/s flow speed. Calculations show the tritium breeding is adequate with enriched Li and appropriate design of the walls not covered by flowing liquid 15% of the total. We have come up with a number of problem areas needing further study to make the design self consistent and workable.

  3. Assessment of bladder wall thickness in women with overactive bladder

    PubMed Central

    Üçer, Oktay; Gümüş, Bilal; Albaz, Ali Can; Pekindil, Gökhan

    2016-01-01

    Objective To compare bladder wall thickness (BWT) between female patients with overactive bladder (OAB) and aged-matched healthy controls. Material and methods Thirty-six female patients with OAB and 31 healthy women were enrolled in the present prospective observational study. Qmax and Qave were measured by using uroflowmetry in all of the women in the patient and control groups, and also maximum bladder capacity (MBC), post- void residual urine (PVRU), prevoiding and postvoiding BWT were measured by using transabdominal ultrasound. Lower urinary tract symptoms of the participants were assessed by using Overactive Bladder Version-8 (OAB-V8) and International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF). All of the data were statistically compared between the patient and control groups. In the patient group, the relationships between parameters were evaluated correlation analysis. Results The mean age of the patients and controls were similar (respectively, 45.58±12.35 and 44.21±11.60 years (p=0.68). The mean pre- and post-voiding BWT, OAB-V8 and ICIQ-SF scores of the patients were significantly higher than the controls. In the patient group, the moderate positive correlations between BWT with Qmax (p=0.02) and Qave (p=0.02) were found. Conclusion This study showed that the BWTs of the female patients with OAB are higher than those of healthy women. Further studies should investigate the changes in BWT of patients with OAB after treatment of OAB. PMID:27274895

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    Glavas, Zoran; Strkalj, Anita; Maldini, Kresimir

    2016-05-01

    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.

  6. 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.

  7. A Digital Stereomicroscopic Study of the Radicular Wall Thickness of Two-Canal Mandibular Incisors

    PubMed Central

    Khedmat, Sedigheh; Mohamadian, Sohayla; Kharrazifard, Mohamad Javad

    2015-01-01

    Objectives: This study aimed to assess the radicular wall thickness in mandibular incisors with two canals and find the maximum and minimum thickness to prevent root canal treatment (RCT) procedural errors. Materials and Methods: A total of 160 extracted mandibular incisors were selected and radiographed; out of which, 55 had two canals. Three parallel transverse sections were made in each tooth at 1mm below the cementoenamel junction (CEJ), mid-root and 1 millimeter to the apex. Specimens were evaluated under a stereomicroscope and the thickness of radicular walls in each section was determined for the buccal, lingual and proximal surfaces. Data were statistically analyzed using Pearson’s correlation coefficient test. Results: The thickness of radicular wall decreased from the cervical towards the apex. In all three sections (cervical, mid-root and apical), the thickness of lingual wall was significantly greater than the buccal wall. Also, the thickness of buccal and lingual walls was significantly higher than that of the proximal walls. Conclusion: The lingual radicular wall had the highest thickness in two-canal mandibular incisors. Therefore, in these teeth, the lingual canal is a better choice for post placement. PMID:26877738

  8. Impact of exercise training on arterial wall thickness in humans

    PubMed Central

    Thijssen, Dick H. J.; Cable, N. Timothy; Green, Daniel J.

    2011-01-01

    Thickening of the carotid artery wall has been adopted as a surrogate marker of pre-clinical atherosclerosis, which is strongly related to increased cardiovascular risk. The cardioprotective effects of exercise training, including direct effects on vascular function and lumen dimension, have been consistently reported in asymptomatic subjects and those with cardiovascular risk factors and diseases. In the present review, we summarize evidence pertaining to the impact of exercise and physical activity on arterial wall remodelling of the carotid artery and peripheral arteries in the upper and lower limbs. We consider the potential role of exercise intensity, duration and modality in the context of putative mechanisms involved in wall remodelling, including haemodynamic forces. Finally, we discuss the impact of exercise training in terms of primary prevention of wall thickening in healthy subjects and remodelling of arteries in subjects with existing cardiovascular disease and risk factors. PMID:22150253

  9. Adaptive ultrasonic measurement of blood vessel diameter and wall thickness: theory and experimental results.

    PubMed

    Rafii, K; Jaffe, J S

    1998-01-01

    An adaptive ultrasonic technique for measuring blood vessel diameter and wall thickness is presented. This technique allows one to use a target-specific transmitted waveform/receiver filter to obtain a larger signal-to-noise ratio (SNR) in the received signal than conventional techniques. Generally, SNR of a received wave increases as the intensity of the transmit wave increases; however, because of the FDA limitations placed on the amount of transmit energy, it is important to be able to make the most efficient use of the energy that is available to obtain the best possible SNR in the received signal. Adaptive ultrasonic measurement makes the most efficient use of the energy that is available by placing the maximum amount of energy in the largest target scattering mode. This results in more energy backscatter from a given target, which leads to a higher SNR in the received waveform. Computer simulations of adaptive ultrasonic measurement of blood vessel diameter show that for a SNR of 0 dB in the transmitted waveform, the standard deviation of the diameter measurements for a custom-designed transmitted waveform is about two orders of magnitude less than the standard deviation of the diameter measurements using more conventional waveforms. Diameter and wall thickness measurement experiments were performed on a latex tube and a bovine blood vessel using both custom-made and conventionally used transmitted waveforms. Results show that the adaptively designed waveform gives a smaller uncertainty in the measurements. The adaptive ultrasonic blood vessel diameter and wall thickness measuring technique has potential applications in examining vessels which are either too deep inside the body or too small for conventional techniques to be used, because of the low SNR in the received signal. PMID:18244211

  10. Continued research on the strain to failure of thick-walled cylinders subjected to internal pressure

    SciTech Connect

    Roach, D.P.; Priddy, T.G.

    1990-01-01

    The determination of the fully plastic response and pressure limit of a pressure vessel is of considerable importance in design. In-house experience in weapon development, new aerospace applications and autofrettage operations all require in-depth knowledge of the strength of high pressure containment structures. This paper presents additional results to support the strain-to-failure analysis of thick-walled cylindrical vessels. Both aluminum and steel, with material properties ranging from ductile to brittle, were tested at stress levels through plastic and strain hardening ranges to fracture. From these tests, the pressure-expansion and through thickness yielding characteristics were determined for these specimens. The critical effective plastic strain depends on the level of tensile stress triaxiality which varies through the wall thickness. It is shown that the proposed strain-to-failure criterion is based on this triaxiality of stress in the critical region and can be used to predict the complete pressure versus strain relations and maximum pressure for the test cylinders. 17 refs., 12 figs.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Control of domain wall thickness by spatial modulation of uniaxial anisotropy and exchange stiffness parameters

    NASA Astrophysics Data System (ADS)

    Arai, Hiroko; Imamura, Hiroshi

    2015-03-01

    The effect of spatial modulation of the uniaxial anisotropy (K) and exchange stiffness (A) parameters on the domain wall thickness was theoretically studied. We derived the Euler-Lagrange equation and the Landau-Lifshitz-Gilbert equation considering the modulation of K and A, and showed that the modulation of A gives rise to an additional term consisting of the first derivatives of A and the magnetization unit vector. Owing to this term, the modulation of A is more effective to modify the domain wall thickness than K. The condition for domain wall pinning by controlling its thickness through the modulation of K and A was also obtained.

  16. 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.

  17. 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.

  18. 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.

  19. Colonic wall thickness measured by ultrasound: striking differences in patients with cystic fibrosis versus healthy controls.

    PubMed Central

    Haber, H P; Benda, N; Fitzke, G; Lang, A; Langenberg, M; Riethmüller, J; Stern, M

    1997-01-01

    BACKGROUND: Colonic strictures represent an advanced stage of fibrosing colonopathy in patients with cystic fibrosis. AIMS: To clarify whether ultrasonography can identify patients with an early stage of fibrosing colonopathy and to determine clinical factors that influence bowel wall thickening. PATIENTS: Ninety patients with cystic fibrosis, median age 10 years, and 46 healthy controls, median age 13 years, were investigated. METHODS: Bowel wall thickness was measured by ultrasound in a prospective study. RESULTS: In cystic fibrosis, wall thickness of both small intestine and colon was significantly (p < 0.0001) higher than in controls; 81% of patients with cystic fibrosis had a maximum colon wall thickness at any site of 2 mm or more, a value that was never reached by controls. The maximum colon wall thickness was 6.5 mm. Bowel wall thickness was unchanged at re-examination after one year. There was no progression even with high dose pancreatic supplements. There was no association between bowel wall thickness and clinical features such as previous meconium ileus, intestinal resection, distal intestinal obstruction syndrome, abdominal pain, or pancreatic enzyme dose. CONCLUSIONS: There is genuine intestinal involvement in cystic fibrosis; in a few cases this could lead to fibrosing colonopathy. Images PMID:9135533

  20. 49 CFR 179.500-4 - Thickness of wall.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the marked test pressure of the tank, the calculated fiber stress in psi at inner wall of tank multiplied by 3.0 will not exceed the tensile strength of any specimen taken from the tank and tested as... maximum marked test pressure permitted to be marked on the tank shall be made by the formula: P = [10S(D...

  1. 49 CFR 179.500-4 - Thickness of wall.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... pressure equal to 7/10 of the marked test pressure of the tank, the calculated fiber stress in psi at inner wall of tank multiplied by 3.0 will not exceed the tensile strength of any specimen taken from the tank... to determine the maximum marked test pressure permitted to be marked on the tank shall be made by...

  2. 49 CFR 179.500-4 - Thickness of wall.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... the marked test pressure of the tank, the calculated fiber stress in psi at inner wall of tank multiplied by 3.0 will not exceed the tensile strength of any specimen taken from the tank and tested as... maximum marked test pressure permitted to be marked on the tank shall be made by the formula: P = [10S(D...

  3. 49 CFR 179.500-4 - Thickness of wall.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... the marked test pressure of the tank, the calculated fiber stress in psi at inner wall of tank multiplied by 3.0 will not exceed the tensile strength of any specimen taken from the tank and tested as... maximum marked test pressure permitted to be marked on the tank shall be made by the formula: P = [10S(D...

  4. 49 CFR 179.500-4 - Thickness of wall.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the marked test pressure of the tank, the calculated fiber stress in psi at inner wall of tank multiplied by 3.0 will not exceed the tensile strength of any specimen taken from the tank and tested as... maximum marked test pressure permitted to be marked on the tank shall be made by the formula: P = [10S(D...

  5. Real-time velocimetry for evaluation of change in thickness of arterial wall.

    PubMed

    Kanai, H; Koiwa, Y

    2000-03-01

    We previously developed a new method, namely, the phased tracking method, for accurately tracking the movement of the heart wall and arterial wall based on both the phase and magnitude of the demodulated signals to determine the instantaneous position of an object. By this method, the local change in wall thickness during one heartbeat can be determined. We have now developed a real-time system for measuring change in thickness of the myocardium and arterial wall. In this system, four high-speed digital signal processing (DSP) chips are employed for obtaining the initially developed method in real time. The tracking results for both sides of the wall are superimposed on the M (motion)-mode image in the workstation, and the thickness changes of the arterial wall are displayed in real time. Using this system, reported herein, velocity signals of the arterial wall with amplitudes less than several micrometers can be successfully detected in real time with sufficient reproducibility. The elasticity of the arterial wall is evaluated by referring to the blood pressure. In in vivo experiments, the rapid response of the change in wall thickness of the carotid artery to the dose of nitroglycerine (NTG) is evaluated for a young healthy subject and a young smoker. This new real-time system offers potential for quantitative diagnosis of early-stage atherosclerosis by the transient evaluation of the rapid response of the cardiovascular system to physiological stress. PMID:10829692

  6. 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 challenge/growth…

  7. Mitigating the effects of surface morphology changes during ultrasonic wall thickness monitoring

    NASA Astrophysics Data System (ADS)

    Cegla, Frederic; Gajdacsi, Attila

    2016-02-01

    Ultrasonic wall thickness monitoring using permanently installed sensors has become a tool to monitor pipe wall thicknesses online and during plant operation. The repeatability of measurements with permanently installed transducers is excellent and can be in the nanometer range. It has, however, also been shown that the measured wall thickness is dependent on surface morphology and that when there are changes in surface morphology the monitored thickness trends can be affected. With an adaptive cross correlation approach, this effect can be successfully muted. However, under some surface morphology change conditions, this can also lead to inaccuracies. Here, an approach to detect when surface morphology changes can influence trend accuracies is presented. This method requires the combination of measurements from several sensors that independently sample an area where the same wall loss mechanism is assumed to occur. Simulation results for the effectiveness of the technique are presented.

  8. 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.

  9. Optimization of Focal Position of Ultrasonic Beam in Measurement of Small Change in Arterial Wall Thickness

    NASA Astrophysics Data System (ADS)

    Watanabe, Masaru; Kanai, Hiroshi

    2001-05-01

    We have previously developed a method for measurement of a small change in thickness of the arterial wall during a single cardiac cycle [H. Kanai, M. Sato, Y. Koiwa and N. Chubachi: IEEE Trans. UFFC 43 (1996) 791]. The resultant change in thickness is shown to be useful for the in vivo assessment of the regional elasticity of the arterial wall. Although the accuracy of the measurement of the change in thickness is found to be within 1 μm, it is affected by the interference of ultrasonic pulses. In this study, we simulate the propagation of ultrasonic pulses transmitted and received by a linear probe. In the simulation experiments, the ultrasonic pulses generated by a computer are reflected by a tube, which has a small change in wall thickness of 10 μm. The optimum focal position of the ultrasonic beam is determined by evaluating the root-mean-square (rms) error in the measured change in thickness.

  10. Prevalence and histopathological finding of thin-walled and thick-walled Sarcocysts in slaughtered cattle of Karaj abattoir, Iran.

    PubMed

    Nourollahi-Fard, Saeid R; Kheirandish, Reza; Sattari, Saeid

    2015-06-01

    Sarcocystosis is a zoonotic disease caused by Sarcocystis spp. with obligatory two host life cycle generally alternating between an herbivorous intermediate host and a carnivorous definitive host. Some species of this coccidian parasite can cause considerable morbidity and mortality in cattle. The present study was set to investigate the prevalence of Sarcocystis spp. and type of cyst wall in slaughtered cattle of Karaj abattoir, Iran. For this purpose 125 cattle (88 males and 37 females) were investigated for the presence of macroscopic and microscopic Sarcocystis cysts in muscular tissues. No macroscopic Sarcocystis cysts were found in any of the samples. In light microscopy, 121 out of 125 cattle (96.8 %) had thin-walled cysts of Sarcocystis cruzi, while 43 out of them (34.4 %) had thick-walled Sarcocystis cyst. In this survey, the most infected tissue was esophagus and heart and the less was diaphragm. Thin-walled cysts (S. cruzi) mostly found in heart and skeletal muscle showed the less. However, thick-walled cyst (S. hominis or S. hirsuta) mostly were detected in diaphragm, heart muscle showed no thick-walled cyst. No significant relation was observed between age and sex and the rate of infection. The results showed that Sarcocystis cyst is prevalent in cattle in the North part of Iran and the evaluation of infection potential can be useful when considering control programs. PMID:26064016

  11. 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.

  12. 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. PMID:22004927

  13. Simultaneous measurement of sound velocity and wall thickness of a tube.

    PubMed

    He, P

    2001-10-01

    A method for simultaneously measuring the sound propagation velocity and the thickness of each wall on the opposite sides of a tube is presented. The method uses a pair of ultrasound transducers to produce two reflected pulses from the outer and inner surfaces of the tube wall on the each side, and two transmitted pulses, one with and one without the tube sample between the two transducers. Using the time-domain analysis, sound velocity and wall thickness of the tube are determined from the time delays between the three pairs of ultrasound pulses, whereas using the frequency-domain analysis, phase velocity, group velocity, and wall thickness of the tube are determined from the phase differences between the three pairs of ultrasound pulses. Results of measurements on five tube samples are reported. PMID:11775655

  14. 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.

  15. Colonic wall thickness using level sets for CT virtual colonoscopy visual assessment and polyp detection

    NASA Astrophysics Data System (ADS)

    Van Uitert, Robert L.; Summers, Ronald M.

    2007-03-01

    The detection of polyps in virtual colonoscopy is an active area of research. One of the critical elements in detecting cancerous polyps using virtual colonoscopy, especially in conjunction with computer-aided detection, is the accurate segmentation of the colon wall. The large CT attenuation difference between the lumen and inner, mucosal layer of the colon wall makes the segmentation of the lumen easily performed by traditional threshold segmentation techniques. However, determining the location of the colon outer wall is often difficult due to the low contrast difference between the colon wall's outer serosal layer and the fat surrounding the colon. We have developed an automatic, level set based method to determine from a CT colonography scan the location of the colon inner boundary and the colon outer wall boundary. From the location of the inner and outer colon wall boundaries, the wall thickness throughout the colon can be computed. Color mapping of the wall thickness on the colon surface allows for easy visual determination of potential regions of interest. Since the colon wall tends to be thicker at polyp locations, potential polyps also can be detected automatically at sites of increased colon wall thickness. This method was validated on several CT colonography scans containing optical colonoscopy-proven polyps. The method accurately determined thicker colonic wall regions in areas where polyps are present in the ground truth datasets and detected the polyps at a false positive rate between 44.4% and 82.8% lower than a state-of-the-art curvature-based method for initial polyp detection.

  16. Surface plasmon and photonic mode propagation in gold nanotubes with varying wall thickness

    SciTech Connect

    Kohl, Jesse; Fireman, Micha; O'Carroll, Deirdre M.

    2011-12-15

    Gold nanotube arrays are synthesized with a range of wall thicknesses (15 to >140 nm) and inner diameters of {approx}200 nm using a hard-template method. A red spectral shift (>0.39 eV) with decreasing wall thickness is observed in dark-field spectra of nanotube arrays and single nanowire/nanotube heterostructures. Finite-difference-time-domain simulations show that nanotubes in this size regime support propagating surface plasmon modes as well as surface plasmon ring resonances at visible wavelengths (the latter is observed only for excitation directions normal to the nanotube long axis with transverse polarization). The energy of the surface plasmon modes decreases with decreasing wall thickness and is attributed to an increase in mode coupling between propagating modes in the nanotube core and outer surface and the circumference dependence of ring resonances. Surface plasmon mode propagation lengths for thicker-walled tubes increase by a factor of {approx}2 at longer wavelengths (>700 nm), where ohmic losses in the metal are low, but thinner-walled tubes (30 nm) exhibit a more significant increase in surface plasmon propagation length (by a factor of more than four) at longer wavelengths. Additionally, nanotubes in this size regime support a photonic mode in their core, which does not change in energy with changing wall thickness. However, photonic mode propagation length is found to decrease for optically thin walls. Finally, correlations are made between the experimentally observed changes in dark-field spectra and the changes in surface plasmon mode properties observed in simulations for the various gold nanotube wall thicknesses and excitation conditions.

  17. Increased Coronary Vessel Wall Thickness in HIV-Infected Young Adults

    PubMed Central

    Abd-Elmoniem, Khaled Z.; Unsal, Aylin B.; Eshera, Sarah; Matta, Jatin R.; Muldoon, Nancy; McAreavey, Dorothea; Purdy, Julia B.; Hazra, Rohan; Hadigan, Colleen; Gharib, Ahmed M.

    2014-01-01

    Background. Individuals with long-term human immunodeficiency virus (HIV) infection are at risk for premature vasculopathy and cardiovascular disease (CVD). We evaluated coronary vessel wall thickening, coronary plaque, and epicardial fat in patients infected with HIV early in life compared with healthy controls. Methods. This is a prospective cross-sectional study of 35 young adults who acquired HIV in early life and 11 healthy controls, free of CVD. Time resolved phase-sensitive dual inversion recovery black-blood vessel wall magnetic resonance imaging (TRAPD) was used to measure proximal right coronary artery (RCA) wall thickness, and multidetector computed tomography (CT) angiography was used to quantify coronary plaque and epicardial fat. Results. RCA vessel wall thickness was significantly increased in HIV-infected patients compared with sex- and race-matched controls (1.32 ± 0.21 mm vs 1.09 ± 0.14 mm, P = .002). No subject had discrete plaque on CT sufficient to cause luminal narrowing, and plaque was not related to RCA wall thickness. In multivariate regression analyses, smoking pack-years (P = .004) and HIV infection (P = .007) were independently associated with thicker RCA vessel walls. Epicardial fat did not differ between groups. Among the HIV-infected group, duration of antiretroviral therapy (ART) (P = .02), duration of stavudine exposure (P < .01), low-density lipoprotein cholesterol (P = .04), and smoking pack-years (P < .01) were positively correlated with RCA wall thickness. Conclusions. This investigation provides evidence of subclinical coronary vascular disease among individuals infected with HIV in early life. Increased duration of ART, hyperlipidemia, and smoking contributed to proximal RCA thickening, independent of atherosclerotic plaque quantified by CT. These modifiable risk factors appear to influence early atherogenesis as measured by coronary wall thickness and may be important targets for CVD risk reduction. PMID:25159580

  18. Computed tomographic assessment of maxillary sinus wall thickness in edentulous patients.

    PubMed

    Yang, S-M; Park, S-I; Kye, S-B; Shin, S-Y

    2012-06-01

    Posterior maxillary region is considered to be the most challenging area for dental implant placement. Lateral window opening is the gold standard procedure for maxillary sinus augmentation in this area. The purpose of this study is to evaluate lateral wall thickness of the maxillary sinus for sinus augmentation using computed tomography (CT) in edentulous patients. Computed tomography images of 302 patients were analysed. Using the maxillary sinus floor as the reference point in edentulous regions, lateral wall thickness was measured on CT scans. After drawing a tangent line at the lowest point of the sinus floor, another perpendicular line to the tangent line was drawn at the same point of the sinus floor. Thickness of the lateral wall of the maxillary sinus was measured using 10DR implant software at 3 (R1), 10 (R2) and 15 mm (R3) from the sinus floor. The mean thickness of the lateral wall of the maxillary sinus from the first premolar to second molar was 1·69 ± 0·71, 1·50 ± 0·72, 1·77 ± 0·78 and 1·89 ± 0·85 mm, respectively. The thickness differed significantly at the R2 and R3 points. Women had thinner lateral walls at the R1 and R2 points at the premolars than did men. At the R2 and R3 points at the second premolar, the mean thickness of smokers was larger than that of non-smokers. There were no significant differences on age or reasons for tooth loss. The changes in the thickness of the lateral wall at different reference points were observed, and CT examinations may help make lateral window without membrane perforation. PMID:22471834

  19. Highly Fluorescent Nanotubes with Tunable Diameter and Wall Thickness Self-Assembled from Asymmetric Perylene Diimides.

    PubMed

    Peng, Cheng; Zhang, Yibin; Zhang, Yifan; Hu, Yanyong; Che, Yanke; Zhao, Jincai

    2016-08-01

    Highly fluorescent bilayer-walled and monolayer-walled nanotubes are assembled from elaborately designed asymmetric perylene diimide (PDI) molecules. The diameter of bilayer-walled nanotubes increases with the size of the branched substituents at the meta-position of the phenyl moiety of PDI molecules, whereas that of monolayer-walled nanotubes remains unchanged regardless of the size of branched substituents. PMID:27375155

  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. PMID:25867620

  1. Comparison of Two Methods of Finite Element Modeling for Elbows with Unequal Wall Thickness

    NASA Astrophysics Data System (ADS)

    Dong, Junhua; Bao, Xiangfu; Zheng, Xize

    In Finite Element Stress Analysis of elbow, its unequal wall thickness can be obtained by two methods: eccentric circle method and multi-spot spline curve drawed according to wall thickness of elbow. In this work, an elbow with constant inner diameter was taken as an illustration and its simulation results based on these two modeling methods were compared under different ratios of central line bend radius to mean diameter of pipe R/D. It is found that modeling method has no effect on the stress analysis results of elbows. But eccentric circle method has the virtue of being easier to implement and can be used without restriction of R/D, so it is an ideal method of finite element modeling for unequal wall thickness elbows. Because the FEA results of equal thickness elbows are recognizably higher than those of elbows with unequal wall thickness, considering non-uniform thickness of elbows is necessary to set up a reasonable safety evaluation for elbows.

  2. Dependence of Thermal Conductivity on Thickness in Single-Walled Carbon Nanotube Films.

    PubMed

    Lee, Kyung-Min; Shrestha, Ramesh; Dangol, Ashesh; Chang, Won Seok; Coker, Zachary; Choi, Tae-Youl

    2016-01-01

    Herein, we report experimentally dependence of thermal conductivity on thickness of single walled carbon nanotubes (SWNTs) thin films; the measurements are based on the micropipette thermal sensor technique. Accurate and well resolved measurements of thermal conductivity made by the micropipette sensor showed a correlated behavior of thickness and thermal conductivity of CNT films that thermal conductivity decreased as thickness increased. The thickness dependence is explained by reduction of mean free path (MFP), which is induced by more intertubular junctions in more dense-packed carbon nanotube (CNT) networks; the thicker SWCNT films were revealed to have higher density. PMID:27398564

  3. Airway wall thickness assessment: a new functionality in virtual bronchoscopy investigation

    NASA Astrophysics Data System (ADS)

    Saragaglia, A.; Fetita, C.; Brillet, P. Y.; Prêteux, F.; Grenier, P. A.

    2007-03-01

    While classic virtual bronchoscopy offers visualization facilities for investigating the shape of the inner airway wall surface, it provides no information regarding the local thickness of the wall. Such information may be crucial for evaluating the severity of remodeling of the bronchial wall in asthma and to guide bronchial biopsies for staging of lung cancers. This paper develops a new functionality with the virtual bronchoscopy, allowing to estimate and map the information of the bronchus wall thickness on the lumen wall surface, and to display it as coded colors during endoluminal navigation. The local bronchus wall thickness estimation relies on a new automated 3D segmentation approach using strong 3D morphological filtering and model-fitting. Such an approach reconstructs the inner/outer airway wall surfaces from multi-detector CT data as follows. First, the airway lumen is segmented and its surface geometry reconstructed using either a restricted Delaunay or a Marching Cubes based triangulation approach. The lumen mesh is then locally deformed in the surface normal direction under specific force constraints which stabilize the model evolution at the level of the outer bronchus wall surface. The developed segmentation approach was validated with respect to both 3D mathematicallysimulated image phantoms of bronchus-vessel subdivisions and to state-of-the-art cross-section area estimation techniques when applied to clinical data. The investigation in virtual bronchoscopy mode is further enhanced by encoding the local wall thickness at each vertex of the lumen surface mesh and displaying it during navigation, according to a specific color map.

  4. Optimization of Condition of Ultrasonic Beam for Measurement of Small Change in Thickness of Arterial Wall

    NASA Astrophysics Data System (ADS)

    Watanabe, Masaru; Hasegawa, Hideyuki; Kanai, Hiroshi

    2002-05-01

    We previously developed a method for measuring small changes in thickness of the arterial wall during one cardiac cycle. Knowledge of this change in thickness is useful for in vivo assessment of the regional elasticity of the arterial wall. In this study, from computer simulations, it is found that measurement error depends on the distance of the ultrasonic beam from the center of the artery and it can be reduced by optimally setting the focal position. In basic experiments using a silicone rubber tube and in in vivo experiments with a human carotid artery, it is found that by optimizing the focal position, measurement of the change in thickness becomes more robust against mispositioning of the ultrasonic beam. From these results, it is demonstrated that optimum focal positioning provides more robustness in measurement, even if there is arterial wall motion causing the position of the ultrasonic beam to deviate from the center of the artery.

  5. General tube law for collapsible thin and thick-wall tubes.

    PubMed

    Kozlovsky, Pavel; Zaretsky, Uri; Jaffa, Ariel J; Elad, David

    2014-07-18

    Modeling the complex deformations of cylindrical tubes under external pressure is of interest in engineering and physiological applications. The highly non-linear post-buckling behavior of cross-section of the tube during collapse attracted researchers for years. Major efforts were concentrated on studying the behavior of thin-wall tubes. Unfortunately, the knowledge on post-buckling of thick-wall tubes is still incomplete, although many experimental and several theoretical studies have been performed. In this study we systematically studied the effect of the wall thickness on post-buckling behavior of the tube. For this purpose, we utilized a computational model for evaluation of the real geometry of the deformed cross-sectional area due to negative transmural (internal minus external) pressure. We also developed an experimental method to validate the computational results. Based on the computed cross-sections of tubes with different wall thicknesses, we developed a general tube law that accounts for thin or thick wall tubes and fits the numerical data of computed cross-sectional areas versus transmural pressures. PMID:24837222

  6. Wall-thickness and midwall-radius variations in ventricular mechanics.

    PubMed

    Chadwick, R S; Ohayon, J; Lewkowicz, M

    1989-05-01

    A fluid-fiber-collagen stress tensor is used to describe the rheology of the left ventricle of the heart. Linear theory is used to find the equilibrium solutions for the end-diastolic and end-systolic states of general axisymmetric shapes that are small perturbations of a thick-walled finite cylinder. The general problem can be studied by superposing the effects of variable midwall radius but constant wall thickness with those of variable wall thickness but constant midwall radius. A Fourier series representation is used to describe the midwall radius and thickness functions. Numerical calculations are performed to determine the deformed geometry and spatial distributions of tissue pressure, stresses, and fiber strains. The calculations proved to be highly accurate when compared to an analytical solution obtained for the special case of no fibers. The results show significant longitudinal differences when compared to results for the cylindrical geometry, with more sensitivity to variation in wall thickness than to variation in midwall radius. PMID:2717607

  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. Thermal Marangoni instability of a thin film flowing down a thick wall deformed in the backside

    NASA Astrophysics Data System (ADS)

    Dávalos-Orozco, L. A.

    2016-05-01

    The nonlinear instability of a thin liquid film flowing down a heated thick wall with deformations in the backside is investigated. Here it is assumed that the wall deformations are sinusoidal in space. Time dependent perturbations are imposed at the origin of the free surface of the film. It is found that the wall deformations have an important influence on the flow instability. Moreover, it is shown that the free surface has a large amplitude spatial response to the backside deformations of the wall. This response increases its amplitude considerably when decreasing the wall spatial wavelength down to the wavelength of the time dependent perturbations. At that point, numerical analysis reveals that the time dependent perturbations in some cases are almost impossible to observe on the free surface response. However, in other cases, their interaction produces large amplitude nonlinear wave modulations.

  9. Investigation of Adiabatic Shear Bands in Thick-Walled Cylinders Collapsed by Electro-Magnetic Driving Forces

    NASA Astrophysics Data System (ADS)

    Lovinger, Z.; Rikanati, A.; Rittel, D.; Rosenberg, Z.

    2009-12-01

    The Thick-Walled Cylinder technique, reported in the literature, employs an explosive cylinder to create the driving force, collapsing the cylindrical sample. This experimental set-up has been established as a controlled and repeatable technique to create and study multiple adiabatic shear bands. Searching to establish a simpler experimental platform to perform large sets of experiments, we have designed an Electro-Magnetic (EM) set-up for the collapse of thick walled cylinders. The EM setup is based on a pulsed current generator using a capacitor bank system. The specimen is an assembly of coaxial cylinders, where the inner and outer cylinders, each attached to an opposite pole, are short-circuited. Upon discharge, a high current flows through the cylinders, in opposite directions, creating repulsive magnetic forces between them. This work presents the design procedure of the specimens using numerical simulations as well as some results for SS304L thick-walled specimens, using this setup. The spatial distribution of the multiple adiabatic shear bands in these experiments is in good agreement with that reported in the literature for the explosive driven experiments with SS304L specimens. Our numerical simulations show good agreement with the experimental results for both global behaviour and shear band distribution.

  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. 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.

  12. Size Dependence in Hexagonal Mesoporous Germanium: Pore Wall Thickness versus Energy Gap and Photoluminescence

    SciTech Connect

    Armatas, G. S.; Kanatzidis, Mercouri G.

    2010-08-10

    A series of hexagonal mesoporous germanium semiconductors with tunable wall thickness is reported. These nanostructures possess uniform pores of 3.1-3.2 nm, wall thicknesses from 1.3 to 2.2 nm, and large internal BET surface area in the range of 404-451 m2/g. The porous Ge framework of these materials is assembled from the templated oxidative self-polymerization of (Ge9)4- Zintl clusters. Total X-ray scattering analysis supports a model of interconnected deltahedral (Ge9)-cluster forming the framework and X-ray photoelectron spectroscopy indicates nearly zero-valence Ge atoms. We show the controllable tuning of the pore wall thickness and its impact on the energy band gap which increases systematically with diminishing wall thickness. Furthermore, there is room temperature photoluminescence emission which shifts correspondingly from 672 to 640 nm. The emission signal can be quenched via energy transfer with organic molecules such as pyridine diffusing into the pores.

  13. Fatigue life improvement of an autofrettage thick-walled pressure vessel with an external groove

    NASA Astrophysics Data System (ADS)

    Koh, Seung K.; Stephens, Ralph I.

    1992-01-01

    This report presents an investigation into a fatigue life improvement of an autofrettaged thick-walled pressure vessel with an external groove subjected to pulsating internal pressure, along with mean strain and mean stress effects on strain-controlled low cycle fatigue behavior. Linear elastic stress analysis of an autofrettaged thick-walled pressure vessel with an external groove is done using a finite element method. Autofrettage loading is performed using a thermal loading analogy. Change of external groove geometry is made using a quasi-optimization technique and finite element method to achieve longer fatigue life by relieving the stress concentration at the groove root. Surface treatment using shot peening is employed to produce compressive residual stresses at the vulnerable surface of the groove root to counteract the high tensile stresses. An evaluation of the fatigue life of an autofrettaged thick-walled pressure vessel with an external groove is done through a series of simulation fatigue tests using C-shaped specimens taken from the thick-walled pressure vessel.

  14. Surgical resection of cerebellar hemangioblastoma with enhanced wall thickness: A report of two cases

    PubMed Central

    SUN, ZHENXING; YUAN, DAN; SUN, YAXING; YAN, PENGXIANG; ZUO, HUANCONG

    2015-01-01

    Hemangioblastomas are tumors of the central nervous system, and the cerebellum is the most common site of occurrence. Cerebellar hemangioblastoma with enhanced wall thickness is rare and often misdiagnosed preoperatively. At present, no unified radiological classification system based on magnetic resonance imaging (MRI) findings exists for cerebellar hemangioblastoma, and this tumor type can be solid or cystic mass, according to the MRI findings. The most common presentation of cerebellar hemangioblastoma observed radiologically is a large sac with small nodules, where the wall of the large cyst is not enhanced. A tumor with enhanced large cysts and tumor nodules is extremely rare. The most effective treatment is complete resection of the cyst and the solid growth. The present case reports the successful treatment of two cases of cerebellar hemangioblastoma with enhanced wall thickness, including the MRI findings for the differential diagnoses and the surgical experiences. PMID:25789007

  15. 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

  16. Real-time dielectric-film thickness measurement system for plasma processing chamber wall monitoring

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Yong; Chung, Chin-Wook

    2015-12-01

    An in-situ real-time processing chamber wall monitoring system was developed. In order to measure the thickness of the dielectric film, two frequencies of small sinusoidal voltage (˜1 V) signals were applied to an electrically floated planar type probe, which is positioned at chamber wall surface, and the amplitudes of the currents and the phase differences between the voltage and current were measured. By using an equivalent sheath circuit model including a sheath capacitance, the dielectric thickness can be obtained. Experiments were performed in various plasma condition, and reliable dielectric film thickness was obtained regardless of the plasma properties. In addition, availability in commercial chamber for plasma enhanced chemical vapor deposition was verified. This study is expected to contribute to the control of etching and deposition processes and optimization of periodic maintenance in semiconductor manufacturing process.

  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. Patient-specific modelling of abdominal aortic aneurysms: The influence of wall thickness on predicted clinical outcomes.

    PubMed

    Conlisk, Noel; Geers, Arjan J; McBride, Olivia M B; Newby, David E; Hoskins, Peter R

    2016-06-01

    Rupture of abdominal aortic aneurysms (AAAs) is linked to aneurysm morphology. This study investigates the influence of patient-specific (PS) AAA wall thickness on predicted clinical outcomes. Eight patients under surveillance for AAAs were selected from the MA(3)RS clinical trial based on the complete absence of intraluminal thrombus. Two finite element (FE) models per patient were constructed; the first incorporated variable wall thickness from CT (PS_wall), and the second employed a 1.9mm uniform wall (Uni_wall). Mean PS wall thickness across all patients was 1.77±0.42mm. Peak wall stress (PWS) for PS_wall and Uni_wall models was 0.6761±0.3406N/mm(2) and 0.4905±0.0850N/mm(2), respectively. In 4 out of 8 patients the Uni_wall underestimated stress by as much as 55%; in the remaining cases it overestimated stress by up to 40%. Rupture risk more than doubled in 3 out of 8 patients when PS_wall was considered. Wall thickness influenced the location and magnitude of PWS as well as its correlation with curvature. Furthermore, the volume of the AAA under elevated stress increased significantly in AAAs with higher rupture risk indices. This highlights the sensitivity of standard rupture risk markers to the specific wall thickness strategy employed. PMID:27056256

  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. Bladder wall thickness in the assessment of neurogenic bladder: a translational discussion of current clinical applications.

    PubMed

    Sturm, Renea M; Cheng, Earl Y

    2016-01-01

    The prospective trial by Kim et al. "Can Bladder Wall Thickness Predict Videourodynamic Findings in Children with Spina Bifida?" published in Journal of Urology investigated the measurement of bladder wall thickness (BWT) as a non-invasive assessment tool for lower urinary tract changes in neurogenic bladder (NGB). In this study, no significant association was observed between BWT and high-risk urodynamic parameters. This editorial discusses the basic science of bladder wall thickening as well as prior studies relating wall thickness to clinical parameters. Although Kim et al. provide a unique literature contribution in terms of assessment of BWT at defined percent cystometric capacity, specific aspects of study methodology and population may have contributed to a lack of correlation with high-risk urodynamic findings. The application of non-invasive modalities to lower urinary tract assessment of NGB remains a promising and relevant area of future research to prevent progression to end stage lower urinary tract changes for all individuals with spina bifida. PMID:26889485

  2. Bladder wall thickness in the assessment of neurogenic bladder: a translational discussion of current clinical applications

    PubMed Central

    Sturm, Renea M.

    2016-01-01

    The prospective trial by Kim et al. “Can Bladder Wall Thickness Predict Videourodynamic Findings in Children with Spina Bifida?” published in Journal of Urology investigated the measurement of bladder wall thickness (BWT) as a non-invasive assessment tool for lower urinary tract changes in neurogenic bladder (NGB). In this study, no significant association was observed between BWT and high-risk urodynamic parameters. This editorial discusses the basic science of bladder wall thickening as well as prior studies relating wall thickness to clinical parameters. Although Kim et al. provide a unique literature contribution in terms of assessment of BWT at defined percent cystometric capacity, specific aspects of study methodology and population may have contributed to a lack of correlation with high-risk urodynamic findings. The application of non-invasive modalities to lower urinary tract assessment of NGB remains a promising and relevant area of future research to prevent progression to end stage lower urinary tract changes for all individuals with spina bifida. PMID:26889485

  3. 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.

  4. Chest wall thickness in military personnel: implications for needle thoracentesis in tension pneumothorax.

    PubMed

    Harcke, H Theodore; Pearse, Lisa A; Levy, Angela D; Getz, John M; Robinson, Stephen R

    2007-12-01

    Needle thoracentesis is an emergency procedure to relieve tension pneumothorax. Published recommendations suggest use of angiocatheters or needles in the 5-cm range for emergency treatment. Multidetector computed tomography scans from 100 virtual autopsy cases were used to determine chest wall thickness in deployed male military personnel. Measurement was made in the second right intercostal space at the midclavicular line. The mean horizontal thickness was 5.36 cm (SD = 1.19 cm) with angled (perpendicular) thickness slightly less with a mean of 4.86 cm (SD 1.10 cm). Thickness was generally greater than previously reported. An 8-cm angiocatheter would have reached the pleural space in 99% of subjects in this series. Recommended procedures for needle thoracentesis to relieve tension pneumothorax should be adapted to reflect use of an angiocatheter or needle of sufficient length. PMID:18274025

  5. Ultrasonic Wall Thickness Monitoring at High Temperatures (>500 °C)

    NASA Astrophysics Data System (ADS)

    Cegla, F. B.; Allin, J.; Davies, J. O.; Collins, P.; Cawley, P.

    2011-06-01

    Corrosion and erosion shorten the life of components that are used in the petrochemical industry. In order to mitigate the safety and financial risks posed by the degradation mechanisms, plant operators monitor wall thicknesses at regular inspection intervals. In high temperature locations inspections have to be carried out at plant shut downs because conventional ultrasonic sensors cannot withstand the high operating temperatures. The authors have developed a waveguide based high temperature thickness gauge for monitoring of wall thicknesses in high temperature areas. The waveguide allows the use of conventional transduction systems (max temp. 60 °C) at one end and guides ultrasonic waves into the high temperature region where the inspection is to be carried out. Slender stainless steel waveguides allow a temperature drop of ˜500-600 °C per 200 mm length to be sustained simply by natural convection cooling. This paper describes the technical challenges that had to be overcome (dispersion and source/receiver characteristics) in order to implement this "acoustic cable". A range of experimental results of thickness measurements on components of different thickness, and furnace tests at different temperatures are presented. An accelerated corrosion test that demonstrates the effectiveness of the monitoring for corrosion is also presented.

  6. Elastic analysis of heterogeneous thick-walled spherical pressure vessels with parabolic varying properties

    NASA Astrophysics Data System (ADS)

    Karami, Keyhan; Abedi, Majid; Zamani Nejad, Mohammad; Lotfian, Mohammad Hassan

    2012-12-01

    On the basis of plane elasticity theory (PET), the displacement and stress components in a thick-walled spherical pressure vessels made of heterogeneous materials subjected to internal and external pressure is developed. The mechanical properties except the Poisson's ratio are assumed to obey the parabolic variations throughout the thickness. Effect of material inhomogeneity on the elastic deformations and stresses is investigated. The analytical solutions and the solutions carried out through the FEM have a good agreement. The values used in this study are arbitrary chosen to demonstrate the effect of inhomogeneity on displacements, and stresses distributions.

  7. 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. PMID:26643090

  8. 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.

  9. 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.

  10. Increased wall thickness using ultrasonography is associated with inflammation in an animal model of experimental colitis

    PubMed Central

    Lied, Gülen Arslan; Milde, Anne Marita; Nylund, Kim; Mujic, Maja; Grimstad, Tore; Hausken, Trygve; Gilja, Odd Helge

    2012-01-01

    Experimentally induced colitis is used in animals to investigate pathophysiological mechanisms in inflammatory bowel disease. When following disease course and treatment effects, it should be possible to perform repeated measurements without harming the animals. This pilot study was performed to investigate whether transabdominal ultrasound using a clinical scanner could be used on rats to demonstrate bowel inflammation in an experimental colitis model. Colitis was induced by either 5% dextran sodium sulfate (DSS) in drinking water for 7 days or a single dose of intracolonic trinitrobenzene sulfonic acid (TNBS). Using ultrasonography, wall thickness of distal colon, cecum, and small bowel was recorded prior to and after DSS, and prior to, 2, and 7 days after TNBS. Blood (tumor necrosis factor [TNF]-alpha) and fecal samples (HemoFEC occult blood) were taken from each group on the same days as sonography. Thereafter, rats were killed and specimens for histology were taken. Wall thickness of distal colon, not of cecum or small bowel, increased significantly after 7 days of DSS, and wall thickness of both distal colon and small bowel increased on day 2 and 7 after TNBS. TNF-alpha increased after 7 days in the latter group only. There was a significant correlation between ultrasonographic measurements and combined histology score of distal colon in the DSS group. HemoFEC was also positive in accordance with sonographic and histological features. Increased intestinal wall thickness in response to both DSS- and TNBS-induced colitis was able to be visualized by transabdominal sonography. Moreover, ultrasound findings, occult blood sampling, and histological findings supported each other, indicating that ultrasonography can be used to assess inflammation in a rat experimental model. PMID:23055765

  11. Influence of slab thickness on responses of concrete walls under fire

    SciTech Connect

    Huang, C.L.D.; Ahmed, G.N. )

    1991-01-01

    Of considerable concern in safety assessments of high-temperature nuclear reactors and of tall buildings is the ability to determine the concrete response, and, in turn, its structural integrity after exposure, to a severe thermal environment. Under hostile environmental conditions, the concrete structure could be exposed to extremely high temperatures. The induced gradients of temperature, pressure, and moisture content in concrete provoke internal stresses that may cause microcracks, macrocracks, and explosive spalling of concrete. Thus the integrity of concrete may be questionable, and the prediction of coupled heat and mass transport in concrete under high temperature (fire, for instance) is becoming more and more important. For the purpose of fire safety, concrete walls with different thicknesses exposed to the fire course described by ASTM E119 and the following decay stage specified in ISO 834 standard are considered. A mathematical model, simulating the coupled heat and mass transfer in concrete walls under time-dependent boundary conditions, has been developed and numerically solved. The results predict the pore pressure, temperature, and moisture histories for different concrete wall thicknesses at various depth thickness ratios. The results show that, under fire, thinner slabs are more vulnerable to damages and ruptures than thicker ones.

  12. Safety Analysis Using Lebesgue Strain Measure of Thick-Walled Cylinder for Functionally Graded Material under Internal and External Pressure

    PubMed Central

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

    2013-01-01

    Safety analysis has been done for thick-walled circular cylinder under internal and external pressure using transition theory which is based on the concept of generalized principal Lebesgue strain measure. Results have been analyzed theoretically and discussed numerically. From the analysis, it can be concluded that circular cylinder made of functionally graded material is on the safer side of the design as compared to homogeneous cylinder with internal and external pressure, which leads to the idea of “stress saving” that minimizes the possibility of fracture of cylinder. PMID:24089605

  13. 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.

  14. 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.

  15. 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.

  16. Local Quantification of Wall Thickness and Intraluminal Thrombus Offer Insight into the Mechanical Properties of the Aneurysmal Aorta.

    PubMed

    Martufi, Giampaolo; Satriano, Alessandro; Moore, Randy D; Vorp, David A; Di Martino, Elena S

    2015-08-01

    Wall stress is a powerful tool to assist clinical decisions in rupture risk assessment of abdominal aortic aneurysms. Key modeling assumptions that influence wall stress magnitude and distribution are the inclusion or exclusion of the intraluminal thrombus in the model and the assumption of a uniform wall thickness. We employed a combined numerical-experimental approach to test the hypothesis that abdominal aortic aneurysm (AAA) wall tissues with different thickness as well as wall tissues covered by different thrombus thickness, exhibit differences in the mechanical behavior. Ultimate tissue strength was measured from in vitro tensile testing of AAA specimens and material properties of the wall were estimated by fitting the results of the tensile tests to a histo-mechanical constitutive model. Results showed a decrease in tissue strength and collagen stiffness with increasing wall thickness, supporting the hypothesis of wall thickening being mediated by accumulation of non load-bearing components. Additionally, an increase in thrombus deposition resulted in a reduction of elastin content, collagen stiffness and tissue strength. Local wall thickness and thrombus coverage may be used as surrogate measures of local mechanical properties of the tissue, and therefore, are possible candidates to improve the specificity of AAA wall stress and rupture risk evaluations. PMID:25631202

  17. [Pulse pressure and common carotid arterial wall thickness assessed by ultrasonography].

    PubMed

    Kawamoto, R; Doi, T

    2000-06-01

    This study was conducted on a total of 358 normotensive (mean blood pressure < 107 mmHg) inpatients (182 men and 176 women, mean age: 67.8 years) who had no cardiorenal or nutrition disorders that would affect blood pressure, lipid and glucose metabolism and who had not been given depressors or antilipidemic agents during the four years from September 1995 to August 1999. In addition to the known risk factors for atherosclerosis, the effects of pulse pressure and mean blood pressure on sclerotic changes of the carotid arteries were examined. These sclerotic changes were assessed by measuring the thickness of the combined intima-media of the common carotid artery (carotid arterial wall thickness) by ultrasonography (Hitachi EUB-565) and linear probe (7.5 MHz). When the patients were divided into three groups based on pulse pressure (PP1, lower than 51 mmHg: PP2, 51-65 mmHg; PP3, higher than 65 mmHg), the age of the group with higher pulse pressure was significantly higher (p = 0.0011), women more (p = 0.0315). However there were no differences in background factors such as body mass index, Brinkman index, lipid metabolism, uric acid, and glucose metabolism. There was observed a positive correlation between the mean blood pressure and the pulse pressure for both men and women (r = 0.31, p < 0.001, respectively). As for the relation between the pulse pressures and the blood pressure parameters, the systolic blood pressure, pulse pressure and the mean blood pressure were significantly higher in the group with higher pulse pressure (p < 0.001, respectively), but the diastolic blood pressure was significantly lower (p = 0.0275). As for the relation between the pulse pressure and the carotid wall thickness, the groups of both men and women with higher pulse pressures had significantly greater carotid arterial wall thickness (p < 0.001, p = 0.0042, respectively). Logistic regression analysis of the carotid arterial wall thickness (defined as hypertrophic if greater than 1

  18. 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.

  19. 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.

  20. 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.

  1. Design of Post-Wall Feed Waveguide for a Parallel Plate Slot Array by an Analysis Model with Corrected Solid-Walls

    NASA Astrophysics Data System (ADS)

    Hashimoto, Koh; Hirokawa, Jiro; Ando, Makoto

    A novel analysis model for post-wall waveguide T-junctions is proposed. Equivalent solid-walls for the post-walls to have equal guided wavelength are corrected in the analysis model so that the wall thickness for the coupling windows is set to the difference in the width between the post-wall and the solid-wall waveguides. The accuracy of the proposed model is confirmed by comparing it to an HFSS analysis for the real structure of the post-wall waveguide T-junction including the post surfaces. 61.25GHz model antennas are fabricated for experimental verification. The reflection of the antenna designed by the modified analysis model is suppressed to below -15dB over a 5.6GHz bandwidth, while that in the antenna designed by the conventional model is larger than -15dB around the design frequency.

  2. 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

  3. 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

  4. 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. PMID:26026778

  5. Influence of remaining dentin wall thickness on the fracture strength of endodontically treated tooth

    PubMed Central

    Haralur, Satheesh B.; Al-Qahtani, Ali Saad; Al-Qarni, Marie Mohammed; Al-Homrany, Rami Mohammed; Aboalkhair, Ayyob Ehsan

    2016-01-01

    Background: Remaining dentin wall thickness may influence the fracture resistance of tooth. Aims: To investigate the effect of various coronal dentin wall widths on the fracture strength of root canal treated teeth. Materials and Methods: Fifty recently extracted single canal mandibular premolars were used for the study. Ten unrestored teeth were used as control (Group 1); remaining teeth were root canal treated and divided into four groups (n = 10). The Groups 2a, 2b and 3a, 3b were having 2.5 mm, 1.5 mm remaining dentin with and without post, respectively. The samples fracture resistance was tested under the universal testing machine. The data were analyzed with one-way ANOVA and post-hoc Tukey test for comparative evaluation. Results: The mean fracture strength observed in Group 1 was (29.75 Mpa) followed by Group 2a (28.97 Mpa), Group 2b (27.70 Mpa), Group 3a (23.39 Mpa), and Group 3b (16.38 Mpa). There was no statistically significant difference between control and Groups 2a and 2b with P > 0.05. The post contributed significantly for fracture resistance in Group 3a. Conclusion: The endodontic post is not required in root canal treated teeth >2.5 mm coronal dentin wall width while the post is essential for a tooth with <1.5 mm dentin wall width to improve fracture resistance. PMID:26957796

  6. Failure prediction method for hydro forming simulation of thick walled tubes

    NASA Astrophysics Data System (ADS)

    Kolleck, Ralf; Auer, Peter; Auer, Gerfried

    2011-05-01

    The industrial production of thick walled hydro formed steel parts is a process difficult to control. In particular the prevention of cracks in the production of these parts is very important. It is of utmost importance to have a virtual tool to predict forming results. Standard methods for the simulation of hydro formed parts base upon processes using a shell element formulation and implement a forming limit curve (FLC) for crack prediction. But the forming limit curve is limited to the case of linear strain paths. The initial FLC is no longer valid in the case of nonlinear strain paths. Because of the geometric specifications of the investigated parts—thick walls, compact dimensions, high strains—and the known limitations of the forming limit curve—which don't accord to the hydro forming process— these standard simulation methods are not applicable for the present investigations. A new approach to simulate thick walled hydro formed parts is the use of a volume element formulation in combination with a more complex failure criterion, which gives information about the risk of ductile normal fracture and ductile shear fractures with nonlinear strain paths. The onset of necking must be predicted directly by the volume elements. The aim of this work is to implement the failure criteria in a hydroforming simulation and to compare the results of the simulation with real cracked test parts. The commercial FEM code PamStamp 2G is used as a solver and a comprehensive fracture model is applied. This fracture model distinguishes between two mechanisms responsible for ductile fracture. One is the void growth and coalescence (ductile normal fracture) and the other one is the shear failure model (ductile shear fracture).

  7. Impaired Gallbladder Motility and Increased Gallbladder Wall Thickness in Patients with Nonalcoholic Fatty Liver Disease

    PubMed Central

    Colak, Yasar; Bozbey, Gulcin; Erim, Tolga; Caklili, Ozge Telci; Ulasoglu, Celal; Senates, Ebubekir; Mutlu, Hasan Huseyin; Mesci, Banu; Doğan, Mehmet Sait; Tasan, Guralp; Enc, Feruze Yilmaz; Tuncer, Ilyas

    2016-01-01

    Background/Aims Nonalcoholic fatty liver disease (NAFLD) is currently the most common chronic liver disease worldwide. Along with the increase in the incidence of NAFLD and associated obesity, an increase in gallbladder disease (GD) has been noted. This has led to the identification of a new disease entity called fatty GD. There is a gap in the literature on the dynamics of gallbladder function in patients with NAFLD. Methods An observational case-control study, a total of 50 patients with biopsy proven NAFLD without gallbladder stone/sludge and 38 healthy comparison subjects were enrolled. Fasting, postprandial gallbladder volumes (PGV), gallbladder ejection fraction (GEF), and fasting gallbladder wall thickness (FGWT) were measured by real-time 2-dimensional ultrasonography. Results Fasting gallbladder wall thickness, fasting gallbladder volumes and PGV were significantly higher in patients with NAFLD than control subjects (P < 0.001, P = 0.006, and P < 0.001, respectively). Gallbladder ejection fraction was significantly lower in the NAFLD group than the controls (P = 0.008). The presence of NAFLD was an independent predictor for GEF, PGV, and FGWT. Also, steatosis grade was an independent predictor for GEF, and GEF was significantly lower in the nonalcoholic steatohepatitis (NASH) subgroup than the controls. Conclusions Gallbladder dysfunction and increase in gallbladder wall thickness exists in asymptomatic (without stone/sludge and related symptoms) patients with NAFLD and are useful in identifying fatty GD. Measurement of these variables in NAFLD patients may be useful in identifying those at higher risk for GD. PMID:26932908

  8. 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.

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

    PubMed

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

    2015-10-01

    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. PMID:26414160

  10. Thermoelastic Analysis of a Functionally Graded Rotating Thick-Walled Tube Subjected to Mechanical and Thermal Loads

    NASA Astrophysics Data System (ADS)

    Xin, Libiao; Yang, Shengyou; Ma, Baoyu; Dui, Guansuo

    2015-11-01

    A thermoelastic solution for the functionally graded rotating thick-walled tube subjected to axisymmetric mechanical and thermal loads is given in terms of volume fractions of constituents. We assume that the tube consists of two linear elastic constituents and the volume fraction of one phase is a power function varied in the radial direction. By using the assumption of a uniform strain field within the representative volume element, the theoretical solutions of the displacement and the stresses are presented. Based on the relation of the volume average stresses of constituents and the macroscopic stresses of the composite material in micromechanics, the present method can avoid the assumption of the distribution regularities of unknown overall material parameters appeared in existing papers, such as Young's modulus, thermal expansion coefficient, thermal conductivity, and density. The effects of the angular velocity, the volume fraction, the ratio of two thermal expansion coefficients, the ratio of two thermal conductivities, and the ratio of two densities on the displacement and stresses are systematically studied, which should help structural engineers and material scientists optimally design thick-walled tube comprised inhomogeneous materials.

  11. 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.

  12. 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.

  13. Electromagnetic acoustic transducers for wall thickness applications in the petrochemical industry

    NASA Astrophysics Data System (ADS)

    Edwards, C.; Dixon, S.; Widdowson, A.; Palmer, S. B.

    2000-05-01

    Electromagnetic acoustic transducers (EMATs) are now becoming widely used in the field, for example for boiler tube wall thickness surveys in Power Generation plant. In general EMATs work efficiently on steel components with a surface oxide layer, where the oxides can be residual mill scale from the steel manufacturing process due to in-service growth in boilers or chemical processing plant. Very often these oxides have rough surfaces and have to be removed prior to conventional ultrasonic inspection. This can be both time consuming and costly, in addition the removal of the protective oxide layer accelerates the future wall lose rate of the pipe or vessel. As well as the Power Generation application, EMATs can also be used for ultrasonic inspection of petrochemical tubulars without having to remove oxides giving the same associated benefits. This paper presents results obtained from laboratory trials of EMAT thickness monitoring of petrochemical plant pipe samples and real EMAT surveys carried out on-site on refinery plant. In parallel with the practical application of EMATs we are studying the underlying physics of operation with the aim of predicting the EMAT performance for steels with and without oxide layers.

  14. 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.

  15. Quantitative Analysis of Intraventricular Dyssynchrony Using Wall Thickness by Multidetector Computed Tomography

    PubMed Central

    Truong, Quynh A.; Singh, Jagmeet P.; Cannon, Christopher P.; Sarwar, Ammar; Nasir, Khurram; Auricchio, Angelo; Faletra, Francesco F.; Sorgente, Antonio; Conca, Cristina; Moccetti, Tiziano; Handschumacher, Mark; Brady, Thomas J.; Hoffmann, Udo

    2009-01-01

    OBJECTIVES We sought to determine the feasibility of cardiac computed tomography (CT) to detect significant differences in the extent of left ventricular dyssynchrony in heart failure (HF) patients with wide QRS, HF patients with narrow QRS, and age-matched controls. BACKGROUND The degree of mechanical dyssynchrony has been suggested as a predictor of response to cardiac resynchronization therapy. There have been no published reports of dyssynchrony assessment with the use of CT. METHODS Thirty-eight subjects underwent electrocardiogram-gated contrast-enhanced 64-slice multidetector CT. The left ventricular endocardial and epicardial boundaries were delineated from short-axis images reconstructed at 10% phase increments of the cardiac cycle. Global and segmental CT dyssynchrony metrics that used changes in wall thickness, wall motion, and volume over time were assessed for reproducibility. We defined a global metric using changes in wall thickness as the dyssynchrony index (DI). RESULTS The DI was the most reproducible metric (interobserver and intraobserver intraclass correlation coefficients ≥0.94, p < 0.0001) and was used to determine differences between the 3 groups: HF-wide QRS group (ejection fraction [EF] 22 ± 8%, QRS 163 ± 28 ms), HF-narrow QRS (EF 26 ± 7%, QRS 96 ± 11 ms), and age-matched control subjects (EF 64 ± 5%, QRS 87 ± 9 ms). Mean DI was significantly different between the 3 groups (HF-wide QRS: 152 ± 44 ms, HF-narrow QRS: 121 ± 58 ms, and control subjects: 65 ± 12 ms; p < 0.0001) and greater in the HF-wide QRS (p < 0.0001) and HF-narrow QRS (p = 0.005) groups compared with control subjects. We found that DI had a good correlation with 2-dimensional (r = 0.65, p = 0.012) and 3-dimensional (r = 0.68, p = 0.008) echocardiographic dyssynchrony. CONCLUSIONS Quantitative assessment of global CT-derived DI, based on changes in wall thickness over time, is highly reproducible and renders significant differences between subjects most likely to

  16. An approach for patient-specific multi-domain vascular mesh generation featuring spatially varying wall thickness modeling.

    PubMed

    Raut, Samarth S; Liu, Peng; Finol, Ender A

    2015-07-16

    In this work, we present a computationally efficient image-derived volume mesh generation approach for vasculatures that implements spatially varying patient-specific wall thickness with a novel inward extrusion of the wall surface mesh. Multi-domain vascular meshes with arbitrary numbers, locations, and patterns of both iliac bifurcations and thrombi can be obtained without the need to specify features or landmark points as input. In addition, the mesh output is coordinate-frame independent and independent of the image grid resolution with high dimensional accuracy and mesh quality, devoid of errors typically found in off-the-shelf image-based model generation workflows. The absence of deformable template models or Cartesian grid-based methods enables the present approach to be sufficiently robust to handle aneurysmatic geometries with highly irregular shapes, arterial branches nearly parallel to the image plane, and variable wall thickness. The assessment of the methodology was based on i) estimation of the surface reconstruction accuracy, ii) validation of the output mesh using an aneurysm phantom, and iii) benchmarking the volume mesh quality against other frameworks. For the phantom image dataset (pixel size 0.105 mm; slice spacing 0.7 mm; and mean wall thickness 1.401±0.120 mm), the average wall thickness in the mesh was 1.459±0.123 mm. The absolute error in average wall thickness was 0.060±0.036 mm, or about 8.6% of the largest image grid spacing (0.7 mm) and 4.36% of the actual mean wall thickness. Mesh quality metrics and the ability to reproduce regional variations of wall thickness were found superior to similar alternative frameworks. PMID:25976018

  17. An Approach for Patient-Specific Multi-domain Vascular Mesh Generation Featuring Spatially Varying Wall Thickness Modeling

    PubMed Central

    Raut, Samarth S.; Liu, Peng; Finol, Ender A.

    2015-01-01

    In this work, we present a computationally efficient image-derived volume mesh generation approach for vasculatures that implements spatially varying patient-specific wall thickness with a novel inward extrusion of the wall surface mesh. Multi-domain vascular meshes with arbitrary numbers, locations, and patterns of both iliac bifurcations and thrombi can be obtained without the need to specify features or landmark points as input. In addition, the mesh output is coordinate-frame independent and independent of the image grid resolution with high dimensional accuracy and mesh quality, devoid of errors typically found in off-the-shelf image-based model generation workflows. The absence of deformable template models or Cartesian grid-based methods enables the present approach to be robust by handling aneurysmatic geometries with highly irregular shapes, arterial branches nearly parallel to the image plane, and variable wall thickness. The assessment of the methodology was based on i) estimation of the surface reconstruction accuracy, ii) validation of the output mesh using an aneurysm phantom, and iii) benchmarking the volume mesh quality against other frameworks. For the phantom image dataset (pixel size 0.105 mm; slice spacing 0.7 mm; mean wall thickness 1.401 ± 0.120 mm), the average wall thickness in the mesh was 1.459 ± 0.123 mm. The absolute error in average wall thickness was 0.060 ± 0.036 mm, or about 8.6% of the largest image grid spacing (0.7 mm) and 4.36% of the actual mean wall thickness. Mesh quality metrics and the ability to reproduce regional variations of wall thickness were found superior to similar alternative frameworks. PMID:25976018

  18. 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.

  19. 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).

  20. First wall and blanket design for a high wall loading compact tokamak power reactor

    SciTech Connect

    Sviatoslavsky, I.N.; Abdel-Khalik, S.I.; Corradini, M.L.; El-Afify, M.; Huh, K.Y.; Kuleinski, G.L.; Wittenberg, L.J.

    1985-07-01

    Among the specific limitations which tend to complicate a compact high wall loading (HWL) tokamak reactor design are high surface and nuclear heating, compactness leading to crowded components, unlikely breeding on the inboard side and frequent first wall/blanket replacement. This paper describes the mechanical, thermal hydraulic and tritium aspects of an improved blanket design for a high ..beta.. (20%), high wall loading (R 10 MW/m/sup 2/) compact fusion power reactor of 1000 MW /sub th/ power output.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Conceptual design strategy for liquid-metal-wall inertial-fusion reactors

    SciTech Connect

    Monsler, M.J.; Meier, W.R.

    1981-02-01

    The liquid-metal-wall chamber has emerged as an attractive reactor concept for inertial fusion energy conversion. The principal feature of this concept is a thick, free-flowing blanket of liquid metal used to protect the structure of the reactor. The development and design of liquid-metal-wall chambers over the past decade provides a basis for formulating a conceptual design strategy for such chambers. Both the attractive and unattractive features of a LMW chamber are enumerated, and a design strategy is formulated which accommodates the engineering constraints while minimizing the liquid-metal flow rate.

  6. Interventricular Septum and Posterior Wall Thickness Are Associated With Higher Systolic Blood Pressure.

    PubMed

    Eliakim-Raz, Noa; Prokupetz, Alex; Gordon, Barak; Shochat, Tzippy; Grossman, Alon

    2016-07-01

    Elevated blood pressure (BP) is a known factor that affects the structure of the left ventricle. The association between left ventricular hypertrophy (LVH) and BP in normotensive individuals is poorly understood. All individuals who underwent routine echocardiography and BP measurements as aircrew candidates for the Israeli Air Force in the years 2006 to 2012 were identified. Participants with normal values were included. Associations between echocardiographic characteristics and BP were studied. A total of 2386 participants were included. Mean systolic BP was 125.31±11.18 mm Hg and mean diastolic BP was 68.69±9.02 mm Hg. Interventricular septal (IVS) thickness was positively correlated with systolic BP (P<.001, correlation coefficient 0.121) and significantly inversely correlated with heart rate and hematocrit level (P<.001 for both). Men with evidence of IVS or posterior wall thickening on echocardiography, even within the normal range, may require a closer follow-up of BP. PMID:26607051

  7. 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.

  8. Residual stress effect on fatigue crack growth in thick wall cylinders

    SciTech Connect

    Kiciak, A.; Glinka, G.; Burns, D.J.

    1995-11-01

    Recently derived weight functions for a single, semi-elliptical, longitudinal crack in a thick wall cylinder with the diameter ratio D{sub 0}/D{sub i} = 2, have been used to analyze fatigue crack propagation in autofrettaged and non-autofrettaged, pressurized cylinders. Two levels of autofrettage, 30 and 60%, have been considered. The influences of the level of autofrettage, surface crack closure, and different sets of parameters of crack closure, and different sets of parameters of crack propagation relation have been investigated. The development of cracks has been compared to the experimental results. The results of analyses confirm beneficial influence of autofrettage. It has been shown that the discrepancies between the observed and calculated crack developments cannot be ascribed to the influence of surface crack closure. The comparison of the experiments and predictions unveils the need for an additional series of experiments.

  9. Preferred propagation patterns of axial surface cracks in thick-walled cylinders

    SciTech Connect

    Perez, E.H.; Kendall, D.P.

    1996-12-01

    Semi-elliptical axial surface cracks, growing due to cyclic pressure loading in thick-walled cylinders undergo significant shape change during the propagation process. These growing cracks change their shapes such that they approach and follow preferred propagation patterns (PPPs). These PPPs depend on the diameter ratio of the cylinder and on the fatigue crack propagation constant, ``m`` in the Paris equation. The objective of this paper is to show the crack shape variation during fatigue crack growth using linear elastic fracture mechanics. It is shown that a crack whose initial shape does not agree with this preferred propagation pattern will grow such that its shape converges to the preferred pattern. The results of this study also show the effect of autofrettage on the PPPs and the final shape of the cracks at breakthrough.

  10. Facilitating protein crystal cryoprotection in thick-walled plastic capillaries by high-pressure cryocooling

    PubMed Central

    Chen, Yi-Fan; Tate, Mark W.; Gruner, Sol M.

    2009-01-01

    Many steps in the X-ray crystallographic solution of protein structures have been automated. However, the harvesting and cryocooling of crystals still rely primarily on manual handling, frequently with consequent mechanical damage. An attractive alternative is to grow crystals directly inside robust plastic capillaries that may be cryocooled and mounted on the beamline goniometer. In this case, it is still desirable to devise a way to cryoprotect the crystals, which is difficult owing to the poor thermal conductivity of thick plastic capillary walls and the large thermal mass of the capillary and internal mother liquor. A method is described to circumvent these difficulties. It is shown that high-pressure cryocooling substantially reduced the minimal concentrations of cryoprotectants required to cryocool water inside capillaries without formation of ice crystals. The minimal concentrations of PEG 200, PEG 400 and glycerol necessary for complete vitrification under pressure cryocooling were determined. PMID:19529790

  11. Left Ventricular Relative Wall Thickness Versus Left Ventricular Mass Index in Non-Cardioembolic Stroke Patients

    PubMed Central

    Hashem, M-Sherif; Kalashyan, Hayrapet; Choy, Jonathan; Chiew, Soon K.; Shawki, Abdel-Hakim; Dawood, Ahmed H.; Becher, Harald

    2015-01-01

    Abstract In non-cardioembolic stroke patients, the cardiac manifestations of high blood pressure are of particular interest. Emerging data suggest that echocardiographically determined left ventricular hypertrophy is independently associated with risk of ischemic stroke. The primary objective of this study was to evaluate the frequency of different patterns of left ventricular (LV) remodeling and hypertrophy in a group of consecutive patients admitted with non-cardioembolic stroke or transient ischemic attack (TIA). In particular, we were interested in how often the relative wall thickness (RWT) was abnormal in patients with normal LV mass index (LVMI). As both abnormal RWT and LVMI indicate altered LV remodeling, the secondary objective of this research was to study whether a significant number of patients would be missing the diagnosis of LV remodeling if the RWT is not measured. All patients were referred within 48 hours after a stroke or a TIA for a clinically indicated transthoracic echocardiogram. The echocardiographic findings of consecutive patients with non-cardioembolic stroke or TIA were analyzed. All necessary measurements were performed in 368 patients, who were enrolled in the study. Mean age was 63.7 ± 12.5 years, 64.4% men. Concentric remodeling carried the highest frequency, 49.2%, followed by concentric hypertrophy, 30.7%, normal pattern, 15.5%, and eccentric hypertrophy, 4.1%. The frequency of abnormal left ventricular RWT (80.4%) was significantly higher than that of abnormal LVMI (35.3%), (McNemar P < 0.05). In this group of non-cardioembolic stroke patients, abnormal LV remodeling as assessed by relative wall thickness is very frequent. As RWT was often found without increased LV mass, the abnormal left ventricular geometry may be missed if RWT is not measured or reported. PMID:25997067

  12. Cross-Sectional Elasticity Imaging of Arterial Wall by Comparing Measured Change in Thickness with Model Waveform

    NASA Astrophysics Data System (ADS)

    Tang, Jiang; Hasegawa, Hideyuki; Kanai, Hiroshi

    2005-06-01

    For the assessment of the elasticity of the arterial wall, we have developed the phased tracking method [H. Kanai et al.: IEEE Trans. Ultrason. Ferroelectr. Freq. Control 43 (1996) 791] for measuring the minute change in thickness due to heartbeats and the elasticity of the arterial wall with transcutaneous ultrasound. For various reasons, for example, an extremely small deformation of the wall, the minute change in wall thickness during one heartbeat is largely influenced by noise in these cases and the reliability of the elasticity distribution obtained from the maximum change in thickness deteriorates because the maximum value estimation is largely influenced by noise. To obtain a more reliable cross-sectional image of the elasticity of the arterial wall, in this paper, a matching method is proposed to evaluate the waveform of the measured change in wall thickness by comparing the measured waveform with a template waveform. The maximum deformation, which is used in the calculation of elasticity, was determined from the amplitude of the matched model waveform to reduce the influence of noise. The matched model waveform was obtained by minimizing the difference between the measured and template waveforms. Furthermore, a random error, which was obtained from the reproducibility among the heartbeats of the measured waveform, was considered useful for the evaluation of the reliability of the measured waveform.

  13. A more realistic thermal shock analysis of a radially multicracked thick-walled cylinder

    NASA Astrophysics Data System (ADS)

    Perl, M.; Ashkenazi, A.

    1992-07-01

    Presently available analyses of multicracking of thick-walled cylinders due to an internal thermal shock, model the shock by a temperature step-change at the cylinder bore, yielding a considerably overestimated temperature field through the cylinder's wall. In the present work a more realistic thermal shock model is employed assuming convection boundary conditions at both the inner and the outer cylinder surfaces. Transient mode I stress intensity factors (SIF), resulting from the thermal shock during the firing process in a typical gun barrel, are evaluated for large arrays of radial cracks emanating from the bore surface of the cylinder. The transient thermal analysis as well as the computation of the SIFs is performed via the finite element method. Once the thermal problem is solved, SIFs at various time steps are calculated for numerous crack arrays (2-1024) and for a wide range of relevant crack lengths. The present analysis emphasizes the importance of using the proper thermal shock model by showing that the previously available results are nonconservative, and exemplifies the favorable effect of the above thermal shock on the effective SIF prevailing at the tips of these cracks.

  14. Echocardiographic Manifestations of Glycogen Storage Disease III: Increase in Wall Thickness and Left Ventricular Mass over Time

    PubMed Central

    Vertilus, Shawyntee M.; Austin, Stephanie L.; Foster, Kimberly S.; Boyette, Keri E.; Bali, Deeksha; Li, Jennifer S.; Kishnani, Priya S.; Wechsler, Stephanie Burns

    2013-01-01

    Purpose Glycogen Storage Disease (GSD) type III, glycogen debranching enzyme deficiency, causes accumulation of glycogen in liver, skeletal, and cardiac muscle. Some patients develop increased left ventricular (LV) thickness by echocardiography, but the rate of increase and its significance remain unclear. Methods We evaluated 33 patients with GSD type III, 23 with IIIa and 10 with IIIb, ages 1 month – 55.5 yrs, by echocardiography for wall thickness, LV mass, shortening and ejection fractions, at 1 time point (n = 33) and at 2 time points in patients with more than 1 echocardiogram (13 of the 33). Results Of 23 cross-sectional patients with type IIIa, 12 had elevated LV mass, 11 had elevated wall thickness. One type IIIb patient had elevated LV mass but 4 had elevated wall thickness. For those with multiple observations, 9 of 10 with type IIIa developed increased LV mass over time, with 3 already increased at first measurement. Shortening and ejection fractions were generally normal. Conclusion Elevated LV mass and wall thickness is more common in patients with type IIIa but develops rarely in type IIIb, though ventricular systolic function is preserved. This suggests serial echocardiograms with attention to LV thickness and mass are important for care of these patients. PMID:20526204

  15. Axial Crushing of Thin-Walled Columns with Octagonal Section: Modeling and Design

    NASA Astrophysics Data System (ADS)

    Liu, Yucheng; Day, Michael L.

    This chapter focus on numerical crashworthiness analysis of straight thinwalled columns with octagonal cross sections. Two important issues in this analysis are demonstrated here: computer modeling and crashworthiness design. In the first part, this chapter introduces a method of developing simplified finite element (FE) models for the straight thin-walled octagonal columns, which can be used for the numerical crashworthiness analysis. Next, this chapter performs a crashworthiness design for such thin-walled columns in order to maximize their energy absorption capability. Specific energy absorption (SEA) is set as the design objective, side length of the octagonal cross section and wall thickness are selected as design variables, and maximum crushing force (Pm) occurs during crashes is set as design constraint. Response surface method (RSM) is employed to formulate functions for both SEA and Pm.

  16. 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.

  17. Design and Validation of a Constant Wall Temperature Plate

    NASA Astrophysics Data System (ADS)

    Biles, Drummond; Ebadi, Alireza; Ma, Allen; White, Chris

    2014-11-01

    A thermally conductive constant temperature wall-plate has been constructed and wind tunnel validation tests of the wall-plate design have been performed. The wall-plate is a sectioned wall design, where each section is independently heated and controlled. Each section consists of an aluminum 6061 plate, an array of resistive heaters affixed to the bottom of the aluminum plate, and a calcium silicate holder used for thermal isolation. A 3 × 3 grid of embedded thermocouples in each aluminum plate are used to monitor wall temperature and for feedback control of wall heating. The streamwise (flow direction) length of each section increases with downstream position since the wall heat flux decreases with downstream position.The section components sit in a Delrin (acetal) frame, chosen for its low thermal conductivity and machinability. The wall-plate will be used to investigate thermal transport in non-equilibrium boundary layer flows. In this talk, we report on the validation tests performed to-date to investigate the aerodynamic and thermal performance of the wall-plate, and the capability of the controller to maintain the wall-plate at a pre-selected fixed temperature in steady and unsteady laminar boundary layer flow.

  18. Measurement of Change in Wall Thickness of Cylindrical Shell Due to Cyclic Remote Actuation for Assessment of Viscoelasticity of Arterial Wall

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hideyuki; Kanai, Hiroshi; Koiwa, Yoshiro; Butler, James P.

    2003-05-01

    To characterize tissues in atherosclerotic plaques, we have developed a method, the phased tracking method, for measuring the strain (change in wall thickness) and elasticity of the arterial wall. However, some types of tissue, such as lipids and blood clots, cannot be discriminated from each other based only on elasticity because of the small difference in their elasticity. For more precise tissue characterization, we are attempting to measure the regional viscoelasticity. To determine viscoelastic properties, elastic moduli at multiple frequencies were obtained by generating the change in internal pressure due to remote cyclic actuation. From basic experiments using a silicone rubber tube, it was found that the change in internal pressure at the ultrasonic beam position (for measurement of the elastic modulus) can be generated by remotely applied actuation. Furthermore, from the resultant minute changes in wall thickness of less than 10 μm measured by the phased tracking method, elastic moduli were obtained at multiple actuation frequencies.

  19. Effect of material properties on the strain to failure of thick-walled cylinders subjected to internal pressure

    SciTech Connect

    Roach, D.P.; Priddy, T.G. )

    1994-05-01

    The determination of the fully plastic response and pressure limit of a pressure vessel is of considerable importance in design, especially in autofrettage considerations. This paper presents the results of an experimental study which measured the maximum internal pressure which can be applied to thick-walled cylindrical vessels. Both aluminum and steel, with material properties ranging from ductile to brittle, were tested at stress levels through plastic and strain hardening ranges to fracture. From these tests, the pressure-expansion and through-thickness yielding characteristics were determined for these specimens. It is shown that a strain-to-failure criterion, based on the triaxiality of stress in the critical region, can be used to predict the complete pressure versus strain relations and maximum pressure for these cylinders. A simple tension-true stress-strain relation of the material is employed to analytically predict the response of the cylinder into the plastic regime. Finally, simplified theoretical and empirical formulas for bursting pressures are checked against the experimental results.

  20. Assessment of carotid diameter and wall thickness in ultrasound images using active contours improved by a multiresolution technique

    NASA Astrophysics Data System (ADS)

    Gutierrez, Marco A.; Pilon, Paulo E.; Lage, Silvia G.; Kopel, Liliane; Carvalho, Ricardo T.; Furuie, Sergio S.

    2002-04-01

    Carotid vessel ultrasound imaging is a reliable non-invasive technique to measure the arterial morphology. Vessel diameter, intima-media thickness (IMT) of the far wall and plaque presence can be reliably determined using B-mode ultrasound. In this paper we describe a semi-automatic approach to measure artery diameter and IMT based on an active contour technique improved by a multiresolution analysis. The operator selects a region-of-interest (ROI) in a series of carotid images obtained from B-mode ultrasound. This set of images is convolved with the corresponding partial derivatives of the Gaussian filter. The filter response is used to compute a 2D gradient magnitude image in order to refine the vessel's boundaries. Using an active contour technique the vessel's border is determined automatically. The near wall media-adventitia (NWMA), far wall media-adventitia (FWMA) and far wall lumen-intima (FWLI) borders are obtained by a least-square fitting of the active contours result. The distance between NWMA and FWLI (vessel diameter) and between FWLI and FWMA (far wall intima-media thickness) are obtained for all images and the mean value is computed during systole and diastole. The proposed method is a reliable and reproducible way of assessing the vessel diameter and far wall intima-media thickness of the carotid artery.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Repair of Full-Thickness Defects in Alimentary Tract Wall With Patches of Expanded Polytetrafluoroethylene

    PubMed Central

    Oh, Daniel S.; Manning, Melanie M.; Emmanuel, Janson; Broyles, Stuart E.; Stone, H. Harlan

    2002-01-01

    Objectives To test the efficacy of patches of expanded polytetrafluoroethylene (ePTFE) for the repair of full-thickness defects in alimentary tract wall. Summary Background Data A recent report of successful replacement of duodenal wall with patches of ePTFE was met with skepticism and clearly warranted confirmation as well as evaluation in repair of other segments of the abdominal intestinal tract. Methods Defects of 4 cm2 were created in various segments of canine abdominal alimentary tract (stomach, duodenum, small bowel, and colon) as well as in bladder dome. For the duodenum in 13 dogs, three different ePTFE fabrications were used: CVX (cardiovascular), PDX (preclude dura membrane), and DLM (dual mesh plus). In repair of the other areas in six dogs, the PDX patch was used. When the animals were killed, both gross inspection of the parietes and tissue for histologic study became the basis for evaluation. Peritoneal and intraluminal cultures of the specific study viscera were also taken. Results There were no patch failures. Only six significant adhesions were noted in 3 of the 19 dogs. Serosal surface healing was complete without exception by 1 week in all animals. Patches of CVX and PDX had heaping mucosa at the margin of well-sealed patch edges in the study involving duodenum. However, the DLM patch had an undergrowth of mucosa with partial patch separation by 1 week, beginning patch extrusion into gut lumen at 3 weeks, and total separation of patch with complete mucosal repair at 6 weeks. The fate of the PDX patches at 6 weeks in stomach, small bowel, colon, and bladder was identical to what had been observed for the PDX patch in the duodenum. All peritoneal and bladder cultures had no growth, whereas the contents of the alimentary tract grew expected flora. Conclusions These observations suggest that ePTFE may well be an acceptable membrane for at least temporary replacement of full-thickness hollow viscus defects, even in the face of heavy bacterial

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. Modeling Periodic Adiabatic Shear Bands Evolution in a 304L Stainless Steel Thick-Walled Cylinder

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    The self-organization of multiple shear bands in a 304L stainless steel thick-walled cylinder (TWC) was numerically studied. The microstructures of material lead to the non-uniform distribution of local yield stress, which plays a key role in the formation of spontaneous shear localization. We introduced a probability factor satisfied Gauss 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 indicate that the machined surface at the internal boundary of a 304L stainless steel cylinder provides a work-hardened layer (about 20 μm) which has significantly different microstructures from base material. The work-hardened layer leads to the phenomenon that most shear bands are in clockwise or counterclockwise direction. In our simulation, periodic oriented perturbations were applied to describe the grain orientation in the work-hardened layer, and the spiral pattern of shear bands was successfully replicated.

  12. Computer-aided detection of bladder tumors based on the thickness mapping of bladder wall in MR images

    NASA Astrophysics Data System (ADS)

    Zhu, Hongbin; Duan, Chaijie; Jiang, Ruirui; Li, Lihong; Fan, Yi; Yu, Xiaokang; Zeng, Wei; Gu, Xianfeng; Liang, Zhengrong

    2010-03-01

    Bladder cancer is reported to be the fifth leading cause of cancer deaths in the United States. Recent advances in medical imaging technologies, such as magnetic resonance (MR) imaging, make virtual cystoscopy a potential alternative with advantages as being a safe and non-invasive method for evaluation of the entire bladder and detection of abnormalities. To help reducing the interpretation time and reading fatigue of the readers or radiologists, we introduce a computer-aided detection scheme based on the thickness mapping of the bladder wall since locally-thickened bladder wall often appears around tumors. In the thickness mapping method, the path used to measure the thickness can be determined without any ambiguity by tracing the gradient direction of the potential field between the inner and outer borders of the bladder wall. The thickness mapping of the three-dimensional inner border surface of the bladder is then flattened to a twodimensional (2D) gray image with conformal mapping method. In the 2D flattened image, a blob detector is applied to detect the abnormalities, which are actually the thickened bladder wall indicating bladder lesions. Such scheme was tested on two MR datasets, one from a healthy volunteer and the other from a patient with a tumor. The result is preliminary, but very promising with 100% detection sensitivity at 7 FPs per case.

  13. 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.

  14. Strength-toughness requirements for thick-walled high pressure vessels

    NASA Astrophysics Data System (ADS)

    Kapp, Joseph A.

    1992-05-01

    The strength and toughness requirements of materials used in high pressure vessels has been the subject of some discussion in the meetings of the Materials Task Group of the Special Working Group - High Pressure Vessels. A fracture mechanics analysis has been performed to theoretically establish the required toughness for a high pressure vessel. The analysis is based on the validity requirement for plane-strain fracture of fracture toughness test specimens. This means that at fracture, the crack length, uncracked ligament, and vessel length must each be greater than fifty times the crack tip plastic zone since for brittle fracture to occur. For high pressure piping applications, the limiting physical dimension is the uncracked ligament, since it can be assumed that the other dimensions are always greater than fifty times the crack tip plastic zone. To perform the fracture mechanics analysis, several parameters must be known, including vessel dimensions, material strength, degree of autofrettage, and design pressure. Remarkably, the results of the analysis show that the effects of radius ratio, pressure, and degree of autofrettage can be ignored when establishing strength and toughness requirements for design code purposes. The only parameters that enter into the calculation are yield strength, toughness and vessel thickness. The final results can easily be represented as a graph of yield strength against toughness on which several curves, one for each vessel thickness, are plotted.

  15. 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.

  16. 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.

  17. Reproducibility of Gadolinium Enhancement Patterns and Wall Thickness in Hypertrophic Cardiomyopathy

    PubMed Central

    Rodriguez-Granillo, Gaston A.; Deviggiano, Alejandro; Capunay, Carlos; Zan, Macarena C. De; Carrascosa, Patricia

    2016-01-01

    Background Reproducibility data of the extent and patterns of late gadolinium enhancement (LGE) in hypertrophic cardiomyopathy (HCM) is limited. Objective To explore the reproducibility of regional wall thickness (WT), LGE extent, and LGE patterns in patients with HCM assessed with cardiac magnetic resonance (CMR). Methods The extent of LGE was assessed by the number of segments with LGE, and by the total LV mass with LGE (% LGE); and the pattern of LGE-CMR was defined for each segment. Results A total of 42 patients (672 segments) with HCM constituted the study population. The mean WT measurements showed a mean difference between observers of -0.62 ± 1.0 mm (6.1%), with limits of agreement of 1.36 mm; -2.60 mm and intraclass correlation coefficient (ICC) of 0.95 (95% CI 0.93-0.96). Maximum WT measurements showed a mean difference between observers of -0.19 ± 0.8 mm (0.9%), with limits of agreement of 1.32 mm; -1.70 mm, and an ICC of 0.95 (95% CI 0.91-0.98). The % LGE showed a mean difference between observers of -1.17 ± 1.2 % (21%), with limits of agreement of 1.16%; -3.49%, and an ICC of 0.94 (95% CI 0.88-0.97). The mean difference between observers regarding the number of segments with LGE was -0.40 ± 0.45 segments (11%), with limits of agreement of 0.50 segments; -1.31 segments, and an ICC of 0.97 (95% CI 0.94-0.99). Conclusions The number of segments with LGE might be more reproducible than the percent of the LV mass with LGE. PMID:27305110

  18. Detection of myocardial viability by dobutamine stress echocardiography: incremental value of diastolic wall thickness measurement

    PubMed Central

    Zaglavara, T; Pillay, T; Karvounis, H; Haaverstad, R; Parharidis, G; Louridas, G; Kenny, A

    2005-01-01

    Objective: To assess the diagnostic accuracy of baseline diastolic wall thickness (DWT) alone and as an adjunct to dobutamine stress echocardiography (DSE) for prediction of myocardial viability in patients with ischaemic left ventricular (LV) dysfunction, with the recovery of resting function after revascularisation as the yardstick. Patients: 24 patients with ischaemic LV dysfunction (ejection fraction < 40%) scheduled for surgical revascularisation. Setting: Regional cardiothoracic centre. Methods: All patients underwent DSE before and resting echocardiography six months after revascularisation. DWT was measured in each of the 16 LV segments. A receiver operating characteristic (ROC) and a multi-ROC curve were generated to assess the ability of DWT alone and in combination with DSE to predict myocardial viability. Results: DWT > 0.6 cm provided a sensitivity of 80%, a specificity of 51%, and a negative predictive value of 80% for the prediction of viability in akinetic segments. DSE had an excellent specificity (92%) but a modest sensitivity (60%) in akinetic segments. A combination of improvement at DSE or DWT > 0.8 cm improved sensitivity (90% v 60%, p < 0.001) and negative predictive value (92% v 78%, p  =  0.03) in akinetic segments compared with DSE alone. This was achieved with some loss in specificity (75% v 92%, p  =  0.01) and positive predictive value (71% v 82%, p  =  0.79). Conclusions: DWT measurement may improve the sensitivity of DSE for the detection of myocardial viability. Akinetic segments with DWT > 0.8 cm have a good chance of recovery despite the absence of contractile reserve during DSE. Further testing may be required before excluding myocardial viability in these cases. PMID:15831644

  19. Preparation of Silicon Nitride Multilayer Ceramic Radome Material and Optimal Design of the Wall Structure

    SciTech Connect

    Chen Fei; Shen Qiang; Zhang Lianmeng

    2008-02-15

    A study of silicon nitride ceramic radomes, which includes preparation of the material and optimal design of the radome wall structure, is presented in this paper. Multilayer radome wall structure with high dielectric constant skins and a low dielectric constant core layer is used for broadband application. As a candidate material for both the skins and core layer, silicon nitride ceramics of controlled dielectric constant in the range 3.0{approx}7.5 were prepared by adding different content of sintering aids such as magnesia, alumina, silica and zirconium phosphate binder and choosing suitable sintering methods. A computer aided design (CAD) for the wall structure of silicon nitride multilayer ceramic radome based on microwave equivalent network method is carried out according to design requirements. By optimizing the thickness of skins and core layer, the power transmission efficiency of such a multilayer Si{sub 3}N{sub 4} ceramic radome is calculated. The calculated results suggest that when the dielectric constant of skins lies in the range 6{approx}7.5 and core layer in the range 3.5{approx}4, the power transmission efficiency is above 85% with frequency of 2{approx}18 GHz while the thickness of skins is less than 0.03{lambda} and the thickness ratio of skins to core layer is less than 1:15.

  20. 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.

  1. Permeable wall boundary conditions for transonic airfoil design

    NASA Astrophysics Data System (ADS)

    Leonard, O.; van den Braembussche, R.

    This paper describes a method for the design of airfoils with prescribed Mach number or static pressure distribution along both the suction and pressure sides. The method consists of an iterative procedure, in which the final geometry is obtained through successive modifications of an existing shape. Each modification is computed by solving the Euler equations using permeable wall boundary conditions, in which the required Mach number distribution can be imposed on the airfoil wall. Since the classical slip condition is no longer imposed, the resulting flow is not tangent to the wall. A new geometry is created using this normal velocity component and a transpiration method.

  2. Sarcocystis sinensis is the most prevalent thick-walled Sarcocystis species in beef on sale for consumers in Germany.

    PubMed

    Moré, G; Pantchev, A; Skuballa, J; Langenmayer, M C; Maksimov, P; Conraths, F J; Venturini, M C; Schares, G

    2014-06-01

    Bovines are intermediate hosts of Sarcocystis cruzi, Sarcocystis hirsuta, and Sarcocystis hominis, which use canids, felids, or primates as definitive hosts, respectively. Cattle represent also intermediate hosts of Sarcocystis sinensis, but the definitive hosts of this parasite are not yet known. Sarcocystosis in cattle is frequently asymptomatic. The infection is characterized by the presence of thin-walled (S. cruzi) or thick-walled muscle cysts or sarcocysts (S. hominis, S. sinensis, and S. hirsuta). Recent reports suggest high prevalence of the zoonotic S. hominis in beef in Europe. We therefore aimed at differentiating Sarcocystis spp. in beef offered to consumers in Germany using molecular and microscopical methods, focusing on those species producing thick-walled sarcocysts. A total of 257 beef samples were obtained from different butcheries and supermarkets in Germany and processed by conventional and multiplex real-time PCR. In addition, 130 of these samples were processed by light microscopy and in 24.6% thick-walled cysts were detected. Transmission electron microscopical analysis of six of these samples revealed an ultrastructural cyst wall pattern compatible with S. sinensis in five samples and with S. hominis in one sample. PCR-amplified 18S ribosomal DNA (rDNA) fragments of 28 individual thick-walled cysts were sequenced, and sequence identities of ≥98% with S. sinensis (n = 22), S. hominis (n = 5) and S. hirsuta (n = 1) were observed. Moreover, nine Sarcocystis sp. 18S rDNA full length gene sequences were obtained, five of S. sinensis, three of S. hominis, and one of S. hirsuta. Out of all samples (n = 257), 174 (67.7%) tested positive by conventional PCR and 179 (69.6%) by multiplex real-time PCR for Sarcocystis spp. Regarding individual species, 134 (52%), 95 (37%), 17 (6.6%), and 16 (6.2%) were positive for S. cruzi, S. sinensis, S. hirsuta, and S. hominis, respectively. In conclusion, S. sinensis is the most prevalent thick-walled

  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. Mechanical Performance and Failure Mechanism of Thick-walled Composite Connecting Rods Fabricated by Resin Transfer Molding Technique

    NASA Astrophysics Data System (ADS)

    Liu, Gang; Luo, Chuyang; Zhang, Daijun; Li, Xueqin; Qu, Peng; Sun, Xiaochen; Jia, Yuxi; Yi, Xiaosu

    2015-08-01

    A resin transfer molding technique was used to fabricate thick-walled composite connecting rods, and then the mechanical performance of the connecting rod was studied experimentally, at the same time the stress and failure index distributions were simulated numerically. The experimental results show that under a tensile load, the connecting rod first cracks near the vertex of the triangle areas at the two ends, and then the damage propagates along the interface between the main bearing beam and the triangle area as well as along the round angle of the triangle area. Whereas under a compressive load, the delamination primarily occurs at the corner of the U-shaped flange, and the final destruction is caused by the fracture of fibers in the main bearing beam. The simulated results reveal that the tensile failure is originated from the delamination at the round angle transition areas of the T-joints, and the failure strength is determined by the interlaminar strength. Whereas the compressive failure is caused by the fracture of fibers in the main bearing beam, and the failure strength of the structure is determined by the longitudinal compressive strength of the composite material. The simulated results are basically consistent with the experimental results. Hence the mechanical performance and failure mechanism of the complicated composite structure are revealed in great detail through the coupling of the two kinds of research methods, which is helpful for the optimal design of composite structures.

  5. 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.

  6. 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.

  7. 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

    2016-01-01

    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. 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

  9. 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

  10. 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. PMID:25177718

  11. Using The Descending Aortic Wall Thickness Measured In Transesophageal Echocardiography As A Risk Marker For Aortic Dissection

    PubMed Central

    Fanari, Zaher; Hammami, Sumaya; Hammami, Muhammad Baraa; Hammami, Safa; Eze-Nliam, Chete; Weintraub, William S.

    2015-01-01

    Objective The aim of this study is to estimate whether aortic wall thickness is increased in patients with Aortic dissection (AD) compared to low risk control group and can be used in addition to aortic diameter as a risk marker of AD. Background AD occurs due to pathologies that may increase thickness of the aortic wall. Transesophageal echocardiography (TEE) has the ability to visualize both the thoracic aortic wall and lumen. Aortic diameter has been used to predict aortic dissection and timing of surgery, but it is not always predictive of that risk. Methods In 48 patients with AD who underwent TEE were examined retrospectively and compared to 48 control patients with patent foramen ovale (PFO). We measured aortic diameter at different levels, intimal/medial thickness (IMT) and complete wall thickness (CMT). Demographic data and cardiovascular risk factors were reviewed. The data was analyzed using ANOVA and student t test. Results (AD) patients were older [mean age 66 AD vs. 51 PFO], had more hypertension, diabetes, hyperlipidemia and Coronary artery disease. Both IMT and CMT in the descending aorta were increased in AD group [(1.85 vs. 1.43 mm; P=0.03 and 2.93 vs. 2.46 mm; p=0.01). As expected the diameter of ascending aorta was also greater in AD (4.61 vs. 2.92 cm; P=0.004). Conclusions CMT and IMT in the descending aorta detected by TEE is greater in patients with AD when compared to control and may add prognostic data to that of aortic diameter. PMID:25984293

  12. Shear flow over a plane wall with an axisymmetric cavity or a circular orifice of finite thickness

    NASA Astrophysics Data System (ADS)

    Pozrikidis, C.

    1994-01-01

    Shear flow over a plane wall that contains an axisymmetric depression or pore is studied using a new boundary integral method which is suitable for computing three-dimensional Stokes flow within axisymmetric domains. Numerical results are presented for cavities in the shape of a section of a sphere or a circular cylinder of finite length, and for a family of pores or orifices with finite thickness. The results illustrate the distribution of shear stresses over the plane wall and inside the cavities or pores. It is found that in most cases, the distribution of shear stresses over the plane wall, around the depressions, is well approximated with that for flow over an orifice of infinitesimal thickness for which an exact solution is available. The kinematic structure of the flow is discussed with reference to eddy formation and three-dimensional flow reversal. It is shown that the thickness of a circular orifice or depth of a pore play an important role in determining the kinematical structure of the flow underneath the orifice in the lower half-space.

  13. Recommendations for protecting against failure by brittle fracture: Category II and III ferritic steel shipping containers with wall thickness greater than four inches

    SciTech Connect

    Schwartz, M.W.; Fischer, L.E.

    1996-08-01

    This report provides criteria for selecting ferritic steels that would prevent brittle fracture in Category II and III shipping containers with wall thickness greater than 4 inches. These methods are extensions of those previously used for Category II and III containers less than 4 inches thick and Category I containers more than 4 inches thick.

  14. 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.

  15. 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

  16. Design of Wall Segments for Ferritic Wall Mode studies on HBT-EP

    NASA Astrophysics Data System (ADS)

    Hughes, P.; Bialek, J.; Boozer, A. H.; Mauel, M. E.; Maurer, D. A.; Navratil, G. A.

    2011-10-01

    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. Understanding the interaction of plasmas with a ferromagnetic wall will be crucial physics for these experiments. Although there has been a linear FRWM experiment, 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 an analysis of the plasma-wall coupling constant as a function of ferritic segment configuration and plasma position, as well as comparing material options for magnetic properties, cost, and ease of fabrication. Also, initial modeling, design, and installation of moderate permeability (μ ~ 5) wall segments on HBT-EP will be discussed. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  17. Nonaxisymmetric turbine end wall design: Part 1 -- Three-dimensional linear design system

    SciTech Connect

    Harvey, N.W.; Rose, M.G.; Taylor, M.D.; Shahpar, S.; Hartland, J.; Gregory-Smith, D.G.

    2000-04-01

    A linear design system, already in use for the forward and inverse design of three-dimensional turbine aerofoils, has been extended for the design of their end walls. This paper shows how this method has been applied to the design of a nonaxisymmetric end wall for a turbine rotor blade in linear cascade. The calculations show that nonaxisymmetric end wall profiling is a powerful tool for reducing secondary flows, in particular the secondary kinetic energy and exit angle deviations. Simple end wall profiling is shown to be at least as beneficial aerodynamically as the now standard techniques of differentially skewing aerofoil sections up the span, and (compound) leaning of the aerofoil. A design is presented that combines a number of end wall features aimed at reducing secondary loss and flow deviation. The experimental study of this geometry, aimed at validating the design method, is the subject of the second part of this paper. The effects of end wall perturbations on the flow field are calculated using a three-dimensional pressure correction based Reynolds-averaged Navier-Stokes CFD code. These calculations are normally performed overnight on a cluster of work stations. The design system then calculates the relationships between perturbations in the end wall and resulting changes in the flow field. With these available, linear superposition theory is used to enable the designer to investigate quickly the effect on the flow field of many combinations of end wall shapes (a matter of minutes for each shape).

  18. Student-Designed Cultural Lesson Boards and Wall Maps

    ERIC Educational Resources Information Center

    Beck, Charles R.

    2010-01-01

    Display boards and wall maps, created by a teacher or designed by a company, are a common sight in most elementary classrooms, but students usually have a rather limited role in constructing these materials. The main objective of this article is to describe some techniques for encouraging students to create social studies displays that can serve…

  19. 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. PMID:26520952

  20. 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.

  1. 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.

  2. First wall/blanket/shield design and optimization system

    SciTech Connect

    Gohar, Y.; Baker, C.; Attaya, H.; Cha, Y.; Majumdar, S.; Scandora, T.

    1988-02-01

    First wall/blanket/shield design and optimization system (BSDOS) has been developed to provide a state-of-the-art design tool for fast accurate analysis. In addition, it has been designed to perform several other functions: (1) allowing comparison and evaluation studies for different concepts using the same data bases and ground rules, (2) permitting the use of any figure of merit in the evaluation studies, (3) optimizing the first wall/blanket/shield design parameters for any figure of merit under several design constraints, (4) permitting the use of different reactor parameters in the evaluation and optimization analyses, (5) allowing the use of improved eingineering data bases to study the impact on the design performance for planning future research and development, and (6) evaluating the effect of the data base uncertainties on the design performance. BSDOS is the first design and optimization system to couple the highly interacting neutronics, heat transfer, thermal hydraulics, stress analysis, radioactivity and decay-heat analyses, tritium balance, and capital cost. A brief description of the main features of BSDOS is given in this paper. Also, results from using BSDOS to perform design analysis for several reactor components are presented. 17 refs., 1 fig., 2 tabs.

  3. The gender-specific chest wall thickness prediction equations for routine measurements of 239Pu and 241Am within the lungs using HPGe detectors.

    PubMed

    Vickers, L R

    1996-03-01

    The current chest wall thickness prediction equation is not applicable to use in routine lung counting measurements for detection of low energy photons (17--60 keV) within the lungs of male and female subjects. The current chest wall thickness prediction equation was derived for the NaI-CsI "phoswich" detection system, which is not the routine detection system in use; the subject position was supine, which is not the routine position; the equation did not account for the intercostal tissue thicknesses of muscle and adipose which significantly attenuate low energy photons (17--60keV); it was derived from male subjects only and is used to predict the chest wall thickness of female subjects for whom it is not applicable. The current chest wall thickness prediction equation yields unacceptable percent errors in the HPGe detection efficiency calibration for 239Pu and 241Am (17- and 59.5-keV photons, respectively) relative to the gender-specific HPGe chest wall thickness prediction equations of this paper (+284% to --73% for 239Pu; (+)42% to --39% for 241Am). As a result, use of the current chest wall thickness prediction equation yields unacceptable percent errors (proportional in magnitude to the percent errors in the detection efficiency calibration) in the calculation of the minimum detectable activity (Bq) or in an initial assessment of a radioactive contamination exposure detected by a routine lung count measurement. PMID:8609026

  4. Oscillatory limited compressible fluid flow induced by the radial motion of a thick-walled piezoelectric tube

    NASA Astrophysics Data System (ADS)

    Shin, Dong-Youn; Grassia, Paul; Derby, Brian

    2003-09-01

    A simple oscillatory, slightly compressible, fluid flow model in a thick-walled piezoelectric tube used in a drop-on-demand inkjet print head is developed from the point of view of fluid-structure interaction to take account of pressure wave propagation and pressure loading opposing wall motion. A frequency sweep is performed computationally using the model revealing the first acoustic fluid-structure resonance frequency and the influence of fluid viscosity. The validity of the model, with given information on the speed of sound in a fluid, is evaluated by comparing the theoretically predicted resonance frequency to the experimentally measured resonance frequency. In addition, the intrinsic speed of sound can be easily computed using the measured acoustic resonance frequency and this computed speed of sound agrees closely with speeds of sound reported in the literature.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    We present an automatic segmentation method for 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 were extracted using a graph-theory-based dynamic programming algorithm. The algorithm was tested with pig airway OCT images acquired with a custom built long range endoscopic OCT system. The performance of the algorithm was demonstrated by cross-validation between auto and manual segmentation experiments. Quantitative thicknesses changes in the mucosal layers are obtained automatically for smoke inhalation injury experiments.

  6. Recurrent cystosarcoma phylloides of breast: extensive full-thickness excision of chest wall with immediate repair using steel mesh and a latissimus dorsi myocutaneous flap.

    PubMed

    Mindikoğlu, A N; Aktan, K

    1983-10-01

    The case of a young woman with a massive recurrent cystosarcoma phylloides of the breast is presented in whom a full thickness excision of the chest wall was carried out en bloc together with four ribs. The large full-thickness defect of the chest wall was reconstructed with stainless steel mesh and covered by a latissimus dorsi myocutaneous flap. The management of post-operative paradoxical movement is also described. PMID:6313105

  7. 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

  8. 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.

  9. Metachronous carcinoma of rectum with reconstruction of a full-thickness abdominal wall defect using a pedicled anterolateral thigh flap

    PubMed Central

    Kok, Amy Siu Yan

    2016-01-01

    Reconstruction of large, complex defects of the abdominal wall after resection of malignant tumors can be challenging. The transfer of an anterolateral thigh (ALT) flap is a feasible and effective option. However, no report has been published on the use of ALT flap after metachronous colonic tumor resection so far. We present an original case of resection of metachronous carcinoma of rectum with reconstruction of the abdominal wall defect using an ALT flap harvested with its aponeurosis. The postoperative course was uncomplicated. Functional and esthetic results were satisfactory. There was no postoperative incisional hernia or tumor recurrence. We conclude that abdominal wall defects of large sizes can be successfully reconstructed using an appropriately designed ALT flap; a simple, single-stage effective reconstruction. PMID:27161142

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    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.

  11. 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

  12. 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

  13. 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.

  14. Resistive wall mode active control physics design for KSTAR

    SciTech Connect

    Park, Y. S. Sabbagh, S. A.; Bialek, J. M.; Berkery, J. W.; Bak, J. G.; Lee, S. G.; Oh, Y. K.

    2014-01-15

    As KSTAR H-mode operation approaches the region where the resistive wall mode (RWM) can be unstable, an important issue for future long pulse, high beta plasma operation is to evaluate RWM active feedback control performance using a planned active/passive RWM stabilization system on the device. In particular, an optimal design of feedback sensors allows mode stabilization up to the highest achievable β{sub N} close to the ideal with-wall limit, β{sub N}{sup wall}, with reduced control power requirements. The computed ideal n = 1 mode structure from the DCON code has been input to the VALEN-3D code to calculate the projected performance of an active RWM control system in the KSTAR three-dimensional conducting structure device geometry. Control performance with the midplane locked mode detection sensors, off-midplane saddle loops, and magnetic pickup coils is examined. The midplane sensors measuring the radial component of the mode perturbation is found to be strongly affected by the wall eddy current. The off-axis saddle loops with proper compensation of the prompt applied field are computed to provide stabilization at β{sub N} up to 86% of β{sub N}{sup wall} but the low RWM amplitude computed in the off-axis regions near the sensors can produce a low signal-to-noise ratio. The required control power and bandwidth are also estimated with varied noise levels in the feedback sensors. Further improvements have been explored by examining a new RWM sensor design motivated by the off-midplane poloidal magnetic field sensors in NSTX. The new sensors mounted off of the copper passive stabilizer plates near the device midplane show a clear advantage in control performance corresponding to achieving 99% of β{sub N}{sup wall} without the need of compensation of the prompt field. The result shows a significant improvement of RWM feedback stabilization using the new sensor set which motivates a future feedback sensor upgrade.

  15. Thick growing multilayer nanobrick wall thin films: super gas barrier with very few layers.

    PubMed

    Guin, Tyler; Krecker, Michelle; Hagen, David Austin; Grunlan, Jaime C

    2014-06-24

    Recent work with multilayer nanocoatings composed of polyelectrolytes and clay has demonstrated the ability to prepare super gas barrier layers from water that rival inorganic CVD-based films (e.g., SiOx). In an effort to reduce the number of layers required to achieve a very low oxygen transmission rate (OTR (<0.01 cc/m(2)·day·atm)) in these nanocoatings, buffered cationic chitosan (CH) and vermiculite clay (VMT) were deposited using layer-by-layer (LbL) assembly. Buffering the chitosan solution and its rinse with 50 mM Trizma base increased the thickness of these films by an order of magnitude. The OTR of a 1.6-μm-thick, six-bilayer film was 0.009 cc/m(2)·day·atm, making this the best gas barrier reported for such a small number of layers. This simple modification to the LbL process could likely be applied more universally to produce films with the desired properties much more quickly. PMID:24914613

  16. Thermoacoustic Oscillations (He-4 Taconis Modes) inside a Thick-Walled Tube.

    NASA Astrophysics Data System (ADS)

    Williamson, J. J.; Toshida, S.; Ravikumar, R. V.; Frederking, T. H. K.

    The equations describing thermoacoustic (Taconis) oscillations inside a liquid-level finder do not have a gravitational dependence term. Therefore, examining these oscillatory modes has potential applications for low boiling cryoliquids in micro-gravity environments, particularly in covered, wall-adjacent domains, like cryoliquids in storage containers aboard spacecraft. Because of capillary action, these liquids tend to cling to the walls of the container. We have continued proceeding work (ICEC 16) using a heavy-walled liquid-level finder for cryogenic helium-4 in 1-g experiments. The apparatus used to observe Taconis oscillations is described by Gaffney and Clement, where a long, hollow tube is immersed, open end down, into a tank of liquid helium-4. The oscillations were measured by fitting the closed end of the tube with a rubber membrane having a small permanent magnet attached. Acoustic oscillations in the tube cause vibrations in the membrane-magnet system which were sensed by a pick-up coil, converting the oscillations into an electrical voltage. The oscillations were measured as a function of voltage (i.e., magnet displacement) versus time, i.e., a time series. The immersion length of the Taconis tube in liquid helium was varied from a finite length to "zero" (tube end touching liquid) and beyond "zero" in the gas phase. The purpose was to characterize the dynamics of the Taconis oscillations and examine usage of the Taconis tube as a liquid-level finder for liquid helium in storage tanks in microgravity environments. In order to characterize the underlying dynamics causing the oscillations, Nonlinear Dynamical Analysis (i.e., "Chaos" analysis) of the oscillations was performed. "Chaotic" behavior is summarized as: an erratic-looking system is in fact deterministic and governed by a set of nonlinear differential equations which are highly sensitive to the system's initial conditions. From the time series, a number of characterizations of the underlying

  17. Application of Internal Fusible Chills in Thick-Walled Castings Made of EN-GJS with an Optimized Microstructure

    NASA Astrophysics Data System (ADS)

    Krupa, Wojciech; Tonn, Babette

    2011-01-01

    The degeneration of graphite in thick-walled components made of ductile iron due to slower solidification affects the mechanical properties and is unacceptable for all safety-relevant components. The inoculation of the melt no longer leads to a fine microstructure. After exceeding the critical solidification time, degenerated shapes of graphite are to be expected. The external cooling with a chill-mould does not eliminate graphite degeneration in the thermal centres. The positive effect of these chills is also limited by the wall thickness. The aim of this study was to increase the heat dissipation of the melt by positioning the internal fusible chills in the thermal centre of the mould cavity. This should lead to accelerated solidification. The plate-shaped chills were placed in the middle of rectangular samples. The solidification processes were first simulated with Magmasoft in order to optimize the size and shape of the fusible chills and to thus guarantee a complete dissolving of the chills. A reduction in the solidification time of approximately 15% was achieved. In the experiments thick-walled samples were cast with and without internal fusible chills and compared. Areas with degenerated graphite, including chunky graphite, were found in the centres of the cast samples without internal cooling. Placing fusible chills in castings increased the number of graphite spheroids in the microstructure and exhibited no graphite degeneration. A homogenous microstructure was developed—no residues of the chills were found. Differences in microstructure and mechanical properties between the edges and centres of the casting could be nullified. The optimized graphite morphology of the casting with internal cooling led to an increase in tensile strength in the thermal centre of about 30 MPa (8%). This process was successfully implemented in an industrial environment. Blocks out of EN-GJS-400 for use in hydraulic engineering with a total weight of eight tonnes were cast in

  18. 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

  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. Quantum confinement effect in Bi anti-dot thin films with tailored pore wall widths and thicknesses

    SciTech Connect

    Park, Y.; Hirose, Y.; Fukumura, T.; Hasegawa, T.; Nakao, S.; Xu, J.

    2014-01-13

    We investigated quantum confinement effects in Bi anti-dot thin films grown on anodized aluminium oxide templates. The pore wall widths (w{sub Bi}) and thickness (t) of the films were tailored to have values longer or shorter than Fermi wavelength of Bi (λ{sub F} = ∼40 nm). Magnetoresistance measurements revealed a well-defined weak antilocalization effect below 10 K. Coherence lengths (L{sub ϕ}) as functions of temperature were derived from the magnetoresistance vs field curves by assuming the Hikami-Larkin-Nagaoka model. The anti-dot thin film with w{sub Bi} and t smaller than λ{sub F} showed low dimensional electronic behavior at low temperatures where L{sub ϕ}(T) exceed w{sub Bi} or t.

  1. The use of thick-walled hollow cylinder creep tests for evaluating flow criteria for rock salt

    SciTech Connect

    Morgan, H.S.; Wawersik, W.R.

    1990-01-01

    Finite element simulations of two laboratory creep tests on thick-walled hollow cylinders of rock salt are evaluated to determine if such bench-scale experiments can be used to establish applicability of either von Mises or Tresca stress measures and associated flow conditions. In the tests, the cylinders were loaded axially and pressurized both internally and externally to produce stress fields similar to those found around underground excavations in rock salt. Several different loading stages were used in each test. The simulations show that for each of two creep models studied, quite different deformations of the cylinders are predicted with the Mises and Tresca flow criteria, especially if friction between the cylinders and axial loading platens is ignored. When friction is included in the simulations, the differences in deformation are changed but are sill clearly distinguishable. 10 refs., 10 figs.

  2. Examination of Cell Shape in Wall Thickness Direction for Foamed Polyurethane Resin

    NASA Astrophysics Data System (ADS)

    Kono, Tsutomu; Matsuoka, Shin-Ichi; Araki, Kuninari; Iseki, Takashi

    The foaming flow process of polyurethane resin is difficult because temperature, density and thermal conductivity are changed greatly by heat generation resulting from the mixing reaction of polyol and polyisocyanate resin. It is thought that thermal conductivity and strength are influenced by cell shape after the foaming process. In this study, we evaluate three-dimensional cell shapes by quantitatively observation of the ratio of the diameter of the parallel and the perpendicular section to flow direction, the ratio of the major axis and the minor axis, and direction of the major axis of cells for closed cell shapes in foamed polyurethane resin. It is thought that cell shapes are mainly deformed by shear stress and pressure of adjacent cells. It becomes obvious by cell shape evaluation that cells in the skin layer are compressed in the thickness direction by pressure of adjacent cells, cells between the skin layer and the core layer are stretched perpendicular to the flow direction by shear stress, and cells in the core layer are similar to the sphere shape.

  3. 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.

  4. Design of first walls and beam dumps for Tandem Mirror Experiment Upgrade

    SciTech Connect

    Drake, R.P.; Lang, D.D.; Hunt, A.L.; Pickles, W.L.; Simonen, T.C.; Stack, T.P.; Wilson, K.L.; Baskes, M.I.; Haggmark, L.G.; Malinowski, M.E.

    1982-04-01

    Neutral reflux from the first walls and beam dumps of the Tandem Mirror Experiment (TMX) Upgrade could erode the neutral-beam-fueled end-cell plasma or cool the neutral-beam-heated central-cell plasma. To allow the TMX Upgrade to meet its design parameters, the neutral reflux to the plasma must be much less than the fluxes of both charge-exchange neutral products to the first walls and transmitted neutral-beam atoms to the beam dumps. To achieve this, we intend to evaporate titanium as a getter on the first wall and install vanadium-foil beam dumps. The vanadium beam dumps will be heated by the neutral beam during the shot, releasing most of the implanted hydrogen as they cool radiatively after the shot. The deposited titanium will be thick enough to retain the implanted charge-exchange neutral products. We describe our design of these components, report our estimates of their performance, and compare their performance to the needs of TMX Upgrade.

  5. Application of the new Section XI, A-3000 method for stress intensity factor calculation to thick-walled pressure vessels

    SciTech Connect

    Kendall, D.P.

    1996-12-01

    The ASME Boiler and Pressure Vessel Code, Section XI, Appendix A, Article A-3000 has been recently revised to include a more accurate method for calculating stress intensity factors. It is based on fitting the distribution of the stress normal to the plane of the crack in the uncracked body, over the depth of the crack, with a cubic equation. The coefficients of this equation are used with correction factors given in the code to calculate the stress intensity factors at the deepest point of the crack and near the free surface. Correction factors are given for a range of values of relative crack depth and crack shape. In a pressurized thick-walled cylinder the stresses of interest are the tangential stresses due to internal pressure as given by the Lame Equations, plus the effect of the pressure in the crack. This paper shows that the Lame stresses, as a function of distance from the inner surface, can be accurately fitted with a simple set of cubic equations over the full wall thickness for a wide range of diameter ratios. The coefficients of these equations, combined with the correction factors, are used to calculate stress intensity factors for a range of diameter ratios and at both the deepest point of the crack and near the free surface. The results are compared with stress intensity factors calculated using the linearized stress method proposed by Kendall and Perez. The effect of the plastic zone correction given in the new method is reported. The stress intensity factors due to autofrettage residual stresses calculated by the new method are also reported.

  6. 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. PMID:25517347

  7. 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. PMID:19251354

  8. Estimation of PSD shifts for high-resolution metrology of thickness micro-changes with possible applications in vessel walls and biological membrane characterization.

    PubMed

    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

  9. 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

  10. 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.

  11. 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.

  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. The heart's fibre alignment assessed by comparing two digitizing systems. Methodological investigation into the inclination angle towards wall thickness.

    PubMed

    Lunkenheimer, P P; Redmann, K; Dietl, K H; Cryer, C; Richter, K D; Whimster, W F; Niederer, P

    1997-04-01

    Myocardial contractile pathways which are not aligned strictly parallel to the heart's epicardial surface, give rise to forces which also act in the ventricular dilating direction. We developed a method which allows us to assess any fibre orientation in the three-dimensional myocardial weave. Decollagenized hearts were prepared by peeling-off fibre strands, following their main fibre orientation down to near the endocardium. In the subepicardium the strands followed a course more or less parallel to the epicardium, whereas from the mid-wall on they tended to dive progressively deeper into the wall. The preparation displays more or less rugged surfaces rather than smooth layers. The grooves and crests on the exposed surfaces were sequentially digitized by two methods: (1) Using a magnet tablet (3 Draw Digitizer System, Polhemus, Cochester VTO 5446, USA) on a dilated pig heart we manually followed the crests using a stylus, handling each groove and crest as an individual contractile pathway. (2) A constricted cow heart was digitized using a contact-free optical system (opto TOP, Dr. Breuckmann, Meersburg, Germany), which is based on the principle of imaging triangulation. Using specially developed software the inclination angles of selected crests and grooves with respect to the epicardial surface were calculated. The two digitizing methods yield comparable results. We found a depth- and side-specific weave component inclined to the epi-endocardial direction. This oblique netting component was more pronounced in the inner 1/3 of the wall than in the subepicardium. The inclination angle probably increases with increasing wall thickness during the ejection period. Manual digitizing is an easy and fast method which delivers consistent results comparable with those obtained by the cumbersome high resolution optical method. The rationales for the assessment of transmural fibre inclination are (1) the putative existence of dilating forces inherent in the myocardial weave

  14. 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.

  15. Qualitative Reliability Issues for In-Vessel Solid and Liquid Wall Fusion Designs

    SciTech Connect

    Cadwallader, Lee Charles; Nygren, R. E.

    2001-10-01

    This paper presents the results of a study of the qualitative aspects of plasma facing component (PFC) reliability for actively cooled solid wall and liquid wall concepts for magnetic fusion reactor vessels. These two designs have been analyzed for component failure modes. The most important results of that study are given here. A brief discussion of reliability growth in design is included to illustrate how solid wall designs have begun as workable designs and have evolved over time to become more optimized designs with better longevity. The increase in tolerable heat fluxes shows the improvement. Liquid walls could also have reliability growth if the designs had similar development efforts.

  16. 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

  17. Finite-element modelling of low-temperature autofrettage of thick-walled tubes of the austenitic stainless steel AISI 304 L: Part I. Smooth thick-walled tubes

    NASA Astrophysics Data System (ADS)

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

    1998-01-01

    The stresses and strains introduced by low-temperature autofrettage of smooth thick-walled tubes made of the austenitic stainless steel AISI 304 L were modelled by the finite-element (FE) method. The objective was to show that low-temperature autofrettage is much more efficient than autofrettage at room temperature in enhancing the fatigue resistance by introducing a higher beneficial tangential (hoop) residual compressive stress at the inner part of the tube. Attention was paid to the influences of the autofrettage temperature and pressure, the work hardening and the reverse yielding on the residual stress components and on the total strain components of the tube. The FE calculations confirmed that more beneficial residual stress patterns can be attained by autofrettage at low rather than at room temperature. From the quantitative calculations, the optimal autofrettage temperature and pressure of the tube were concluded to be about 0965-0393/6/1/006/img1 and 4000 bar, respectively. The results of the calculations were shown to be in good agreement with recently measured data.

  18. 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

  19. 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. PMID:26896038

  20. Associations of Anger, Anxiety and Depressive symptoms with Carotid Arterial Wall Thickness: the Multi-Ethnic Study of Atherosclerosis

    PubMed Central

    Ohira, Tetsuya; Diez Roux, Ana V.; Polak, Joseph F.; Homma, Shunichi; Iso, Hiroyasu; Wasserman, Bruce A.

    2015-01-01

    Objective Carotid arterial wall thickness, measured as intima-media thickness (IMT), is an early subclinical indicator of cardiovascular disease. Few studies have investigated the association of psychological factors with IMT across multiple ethnic groups and by gender. Methods We included 6,561 men and women (2,541 whites, 1,790 African Americans, 1,436 Hispanics, and 794 Chinese) aged 45 to 84 years who took part in the first examination of the Multi-Ethnic Study of Atherosclerosis. Associations of trait anger, trait anxiety, and depressive symptoms with mean values of common carotid artery (CCA) and internal carotid artery (ICA) IMTs were investigated using multivariable regression and logistic models. Results In age, gender, race/ethnicity-adjusted analyses, the trait anger score was positively associated with CCA and ICA IMTs (mean differences per one SD increment of trait anger score were 0.014 (95% CI, 0.003–0.025, p=0.01) and 0.054 (0.017–0.090, p=0.004) for CCA and ICA IMTs respectively). Anger was also associated with the presence of carotid plaque (age, gender, and race/ethnicity-adjusted odds ratio per one SD increase in trait anger: 1.27 (95%CI, 1.06–1.52)). The associations of the trait anger score with thicker IMT was attenuated after adjustment for covariates, but remained statistically significant. Associations were stronger in men than in women and in whites than in other race/ethnic groups but heterogeneity was only marginally statistically significant by race/ethnicity. There was no association of depressive symptoms or trait anxiety with IMT. Conclusions Only one of the three measures examined was associated with IMT and the patterns appeared to be heterogeneous across race/ethnic groups. PMID:22511725

  1. 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.

  2. A new direct design method for the medium thickness wind turbine airfoil

    NASA Astrophysics Data System (ADS)

    Wang, Quan; Chen, Jin; Pang, Xiaoping; Li, Songlin; Guo, Xiaofeng

    2013-11-01

    The newly developed integral function of airfoil profiles based on Trajkovski conformal transform theory could be used to optimize the profiles for the thin thickness airfoil. However, it is hard to adjust the coefficients of the integral function for the medium thickness airfoil. B-spline curve has an advantage of local adjustment, which makes it to effectively control the airfoil profiles at the trailing edge. Therefore, a new direct design method for the medium thickness wind turbine airfoil based on airfoil integral expression and B-spline curve is presented in this paper. An optimal mathematical model of an airfoil is built. Two new airfoils with similar thickness, based on the new designed method and the original integral method, are designed. According to the comparative analysis, the CQU-A25 airfoil designed based on the new method exhibits better results than that of the CQU-I25 airfoil which is designed based on the original method. It is demonstrated that the new method is feasible to design wind turbine airfoils. Meanwhile, the comparison of the aerodynamic performance for the CQU-A25 airfoil and for the DU91-W2-250 airfoil is studied. Results show that the maximum lift coefficient and the maximum lift/drag ratio of the CQU-A25 airfoil are higher than the ones of DU91-W2-250 airfoil in the same condition. This new airfoil design method would make it possible to design other airfoils with different thicknesses.

  3. 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.

  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. 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.

  6. 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 Central

    2014-01-01

    Background 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. Methods 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. Results 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. Conclusion 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. PMID:24669780

  7. 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.

  8. 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

  9. A non-destructive experimental investigation of elastic plastic interfaces of autofrettaged thick-walled cylindrical aluminium high pressure vessels

    NASA Astrophysics Data System (ADS)

    Ma, Yanling; Zhang, Shu Yan; Goodway, Chris; Done, Robert; Evans, Beth; Kirichek, Oleg; Bowden, Zoë

    2012-09-01

    Positions of elastic plastic interfaces play a vital role in safe design and safe use of high pressure vessels. The ENGIN-X neutron diffractometer at the ISIS facility was used to measure the residual strain profiles in a series of aluminium vessels which had been subjected to different pressure levels. The positions of elastic plastic interfaces of the autofrettaged pressure vessels were identified. The results revealed that the residual strain magnitude and the depth of the plastic region will increase with increasing autofrettage pressure level. When autofrettage pressure produces an elastic-plastic boundary at a greater depth than the geometric mean position of the vessel wall, reverse yielding will occur, hence the loss of the vessels' elastic ability to its subsequent loading. The neutron experimental results agreed well with both the suggestions from existing literatures and the results from FE simulations.

  10. High-temperature (>500°c) wall thickness monitoring using dry-coupled ultrasonic waveguide transducers.

    PubMed

    Cegla, Frederic B; Cawley, Peter; Allin, Jonathan; Davies, Jacob

    2011-01-01

    Conventional ultrasonic transducers cannot withstand high temperatures for two main reasons: the piezoelectric elements within them depolarize, and differential thermal expansion of the different materials within a transducer causes them to fail. In this paper, the design of a high-temperature ultrasonic thickness gauge that bypasses these problems is described. The system uses a waveguide to isolate the vulnerable transducer and piezoelectric elements from the high-temperature measurement zone. Use of thin and long waveguides of rectangular cross section allows large temperature gradients to be sustained over short distances without the need for additional cooling equipment. The main problems that had to be addressed were the transmission and reception of ultrasonic waves into and from the testpiece that the waveguides are coupled to, and optimization of the wave propagation along the waveguide itself. It was found that anti-plane shear loading performs best at transmitting and receiving from the surface of a component that is to be inspected. Therefore, a nondispersive guided wave mode in large-aspect-ratio rectangular strips was employed to transmit the anti-plane shear loading from the transducer to the measurement zone. Different joining methods to attach the waveguides to the component were investigated and experiments showed that clamping the waveguides to the component surface gave the best results. The thickness of different plate samples was consistently measured to within less than 0.1 mm. Performance at high temperatures was tested in a furnace at 730°C for 4 weeks without signal degradation. Thicknesses in the range of 3 to 25 mm could be monitored using Hanning windowed tonebursts with 2 MHz center frequency. PMID:21244983

  11. Numerical investigation of the heating performance of normal and new designed Trombe wall

    NASA Astrophysics Data System (ADS)

    Rabani, Mehran; Kalantar, Vali

    2016-06-01

    In this paper a numerical comparison has been made between the heating performance of the new designed and normal Trombe wall under Yazd (Iran) desert climate. The new designed Trombe wall increases the indoor space and decreases the implementation cost of the Trombe wall. In addition, it can receive solar intensity from three directions while the normal Trombe wall can only receive the solar intensity from one direction. The numerical simulation shows that the new designed Trombe wall causes the all parts temperature to increase about 10 °C in comparison with the normal Trombe wall. The velocity through the vents and the channel in the new designed Trombe wall is about 0.03 and 0.01 m/s more than that of the normal Trombe wall respectively. Comparison of two systems shows that the maximum hourly stored energy of the new designed Trombe wall is about 1600 kJ/h more than that of the normal system. Also, the new designed Trombe wall improves the average daily heating efficiency about 27 %.

  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. 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

  14. 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. PMID:26305893

  15. The in vivo evaluation of tissue-based biomaterials in a rat full-thickness abdominal wall defect model.

    PubMed

    Bryan, Nicholas; Ahswin, Helen; Smart, Neil; Bayon, Yves; Wohlert, Stephen; Hunt, John A

    2014-05-01

    Hernias are defects in which an anatomical fascia is breached resulting in ectopic positioning of an organ into an orifice which routinely does not contain it. Intervention often involves repositioning translocated organs and repair of damaged fascia using exogenous grafts. Despite hernia prevalence, repairs can still fail due to postoperative complications, such as chronic pain and decreased mobility. This study compared repair capacities and characterized the foreign body response elicited by a number of hernia repair grafts to deduce their bulk inflammatory properties while also concluding the point in their fabrication when these are inferred. Materials derived from human dermis (Alloderm(®) ), porcine dermis (Permacol™, patch A, patch D and Strattice(®) ), porcine small-intestinal submucosa (Surgisis™) and a synthetic (multifilament Surgipro™) were implanted into a rat full-thickness abdominal wall excision model, incubated for up to 2 years and characterized histopathologically. Surgisis™ resorbed the fastest of the materials tested (1-3 months) resulting in a mechanically stable parietal peritoneum. Decellularization using sodium dodecyl sulfate (patch A) stimulated a large early inflammatory response which ultimately may have contributed to increased resorption of porcine dermal matrix however the remaining materials typically persisted throughout the 2-year incubation. Cross-linking porcine dermis using 1,6-hexamethylene disocyanate (vs. an identical noncross-linked counterpart) showed no difference in cell recruitment or material integration over 2 years. Typically Strattice(®) and Alloderm(®) recruited larger early populations of cells than Permacol™; however, over extended periods of time in vivo this response normalized. PMID:24155173

  16. Wall thickness of gas- and marrow-filled avian long bones: measurements on humeri, femora and tibiotarsi in crows (Corvus corone cornix) and magpies (Pica pica).

    PubMed

    Suhai, Bence; Gasparik, Mihály; Csorba, Gábor; Gerics, Balázs; Horváth, Gábor

    2006-01-01

    We studied how the ratio K of the internal to external diameter of gas- and marrow-filled avian long bones follows the biomechanical optima derived for tubular bones with minimum mass designed to fulfil various mechanical requirements. We evaluated radiographs of numerous humeri, femora and tibiotarsi in Corvus corone cornix and Pica pica. The K-values of the gas-filled humerus (K=0.78+/-0.03) and the marrow-filled femur (K=0.79+/-0.02) in Corvus are practically the same, while K of the marrow-filled tibiotarsus (K=0.71+/-0.04) is significantly smaller. The same is true for the gas-filled humerus (K=0.78+/-0.02) and the marrow-filled femur (K=0.77+/-0.02) and tibiotarsus (K=0.67+/-0.05) in Pica. K in Corvus is slightly larger than K in Pica, but the differences are statistically not significant. The standard deviation DeltaK of the tibiotarsi (DeltaK=0.04-0.05) is approximately two times as large as that of the humeri (DeltaK=0.02-0.03) and femora (DeltaK=0.02) in both species. Accepting the assumption of earlier authors that the ratio Q of the marrow to bone density is 0.5, our data show that the marrow-filled tibiotarsi of Corvus and Pica are optimized for stiffness, while the marrow-filled femora are far from any optimum. The relative wall thickness W=1-K of the gas-filled avian humeri studied is much larger than the theoretical optimum W*=1-K*=0.07, and thus these bones are thicker-walled than the optimal gas-filled tubular bone with minimum mass. PMID:16084519

  17. 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. PMID:27056298

  18. 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.

  19. 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

  20. ECO-WALL SYSTEMS: USING RECYCLED MATERIAL IN THE DESIGN OF COMMERCIAL INTERIOR WALL SYSTEMS FOR BUILDINGS

    EPA Science Inventory

    This proposal describes an interdisciplinary project involving students from several academic departments at Miami University in the design of commercial wall systems to be manufactured from recycled materials. The goal of Phase I of the project is to develop and conduct prelimi...

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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. PMID:10591672

  6. 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.

  7. Precise Measurement of Pipe Wall Thickness in Noncontact Manner Using a Circumferential Lamb Wave Generated and Detected by a Pair of Air-Coupled Transducers

    NASA Astrophysics Data System (ADS)

    Nishino, Hideo; Asano, Tadashi; Taniguchi, Yuta; Yoshida, Kenichi; Ogawa, Hitoshi; Takahashi, Masakazu; Ogura, Yukio

    2011-07-01

    In this paper, we present a novel method of accurately estimating pipe wall thickness by detecting the minute difference in the angular wave number of a circumferential (C-) Lamb wave. A C-Lamb wave circling along a circumference of a pipe is transmitted and received by a pair of noncontact air-coupled ultrasonic transducers. For the accurate detection of the angular wave number, 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 method is very useful to monitor the integrity of piping in high-temperature environments because of its noncontact nature. The principle of the method and experimental verification are shown.

  8. An experimental investigation of lead zirconate titanate--epoxy-multi-walled carbon nanotube bulk and flexible thick film composites

    NASA Astrophysics Data System (ADS)

    Banerjee, Sankha

    Piezoelectric sensors and actuators are needed for a wide range of applications from physiological measurement to industrial monitoring systems. Sensors that can be easily integrated with the host, while maintaining high sensitivity and reliability over a wide range of frequencies are not readily feasible and economical with homogenous piezoelectric materials. It is well known that two-phase piezoelectric-epoxy composites offer several benefits over their single phase counterparts, as the properties of the constituent phases combine to improve the range of applicability. However, the piezoelectric properties of these materials suffer from the electrically insulating properties of the epoxy matrix. The electrical properties of the matrix may be enhanced by including electrically conducting inclusions however, less is known about the mechanisms that drive the changes in these properties. Hence, this experimental investigation of sensor materials builds on the previous work in two-phase piezoelectric composites, where the aims are to understand the roles that specific fabrication parameters and inclusion composition play in determining the piezoelectric and dielectric performance the aforementioned composites. The materials under investigation will be comprised of Lead Zirconate Titanate, Epofix Cold-Setting Embedding Resin and multi-walled carbon nanotubes, i.e. the piezoelectric, epoxy and electrical inclusions respectively. Our work suggests that inclusion of MWCNTs enhances the piezoelectric and dielectric properties with increasing volume fraction below the percolation threshold. This work seeks to understand how the processing parameters: poling temperature, poling type and particle distribution influence the contact resistance, space charge double layer at the piezoelectric and conductor interfaces and electric field intensity at the piezoelectric boundary, which all ultimately dictate the piezoelectric and dielectric performance of the composite materials

  9. [New echocardiographic para-apical technic for determining the size and thickness of the wall of the right ventricle in probands and patients with dilated cardiomyopathy].

    PubMed

    Dyczynski, J; Schweitzer, L

    1987-12-01

    To evaluate the right ventricular size and free wall thickness a new echocardiographic para-apical technique was developed. All cases were examined from the para-apical window in the extreme left lateral decubitus position, on a special mattress that allowed us to investigate the total apical region. The para-apical transducer position makes it possible to cut the right ventricle cross-sectionally in serial bread-loafing fashion from the apex to the base, like the left ventricle. In this way, using the M-mode technique, either diameters and/or right ventricular free wall thickness as well as shortening fraction could be estimated. To estimate the usefulness of the para-apical technique, a study was performed in 50 normal subjects as well as in 16 patients with dilated cardiomyopathy. In all patients, standard views and the new para-apical view were performed. In five cases, contrast echocardiography of the heart was performed to verify the right-heart anatomy. In five patients, computer-tomography of the heart was performed to see the position of the right-heart chambers in the chest and to evaluate the new para-apical ultrasound window. The standard values for the right ventricle in the control group were (in mean values): diastolic diameter, 28.61 +/- 3.19 mm; systolic diameter, 19.10 +/- 2.40 mm; free wall thickness, 4.46 +/- 1.06 mm and shortening fraction, 32.42% +/- 4.02%. The examined parameters in patients with dilated cardiomyopathy were: diastolic diameter, mean value 38.63 +/- 5.80 mm; systolic diameter, mean value 32.48 +/- 4.96 mm; free wall thickness, mean value 8.70 +/- 1.05 mm and shortening fraction, mean value 15.96 +/- 4.02%.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3439250

  10. 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

  11. The Solar Dynamic Buffer Zone (SDBZ) curtain wall: Validation and design of a solar air collector curtain wall

    NASA Astrophysics Data System (ADS)

    Richman, Russell Corey

    Given the increases in both the environmental and economic costs of energy, there is a need to design and building more sustainable and low-energy building systems now. Curtain wall assemblies show great promise---the spandrel panels within them can be natural solar collectors. By using a Solar Dynamic Buffer Zone (SDBZ) in the spandrel cavity, solar energy can be efficiently gathered using the movement of air. There is a need for a numerical model capable of predicting performance of an SDBZ Curtain Wall system. This research designed, constructed and quantified a prototype SDBZ curtain wall system through by experimental testing in a laboratory environment. The laboratory experiments focussed on three main variables: air flow through the system, incoming radiation and collector surface type. Results from the experimental testing were used to validate a one-dimensional numerical model of the prototype. Results from this research show a SDBZ curtain wall system as an effective means of reducing building heating energy consumption through the preheating of incoming exterior ventilation air during the heating season in cold climates. The numerical model showed good correlation with experimental results at higher operating flows and at lower flows when using an apparent velocity at the heat transfer boundary layer. A seasonal simulation for Toronto, ON predicted energy savings of 205 kWh/m2 with an average seasonal efficiency of 28%. This is considered in the upper range when compared to other solar air collectors. Given the lack of published literature for similar systems, this research acts to introduce a simple, innovative approach to collect solar energy that would otherwise be lost to the exterior using already existing components within a curtain wall. Specifically, the research has provided: results from experiments and simulation, a first generation numerical model, aspects of design and construction of the SDBZ curtain wall and specific directions for further

  12. 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

  13. Effect of a multi-sided concave liner barrel design on thickness and roughness of teat-end hyperkeratosis.

    PubMed

    Haeussermann, Angelika; Britten, Justine; Britten, Allan; Pahl, Christian; Älveby, Nils; Hartung, Eberhard

    2016-05-01

    In a round liner barrel, the force of the closing liner is transferred by the two opposite sides of the liner wall to the teat apex. Liners with a multi-sided barrel shape close at three or more planes and distribute their force to a larger area of the teat apex. The objective of the study was to investigate effects of a liner with a multi-sided concave barrel design on the degree of teat-end hyperkeratosis, thickness and roughness, and on the time delay until thickness or roughness of teat-end hyperkeratosis responded to the experimental liner. The investigations were done on two dairy farms, one in USA and one in Germany. A split-udder arrangement of liners was used, and control treatment was a liner with round barrel shape. The test period comprised 14 weeks in the first study and 16 weeks in the second study. Thickness of teat-end hyperkeratosis was influenced by farm and test week. Roughness was influenced by farm, test week and treatment. In the first study, the incidence of rough teat-end hyperkeratosis was about 28 and 42% lower in teats milked with the experimental liner than in teats milked with the control liner by test weeks 11 and 14, respectively. In the second study, incidence of rough teat-end hyperkeratosis was rare in general, and in addition hardly occurred in teats milked with the experimental liner. The results indicate that the barrel design of the experimental liner causes similar effects on different farms but magnitude of the effect depends on initial incidence of teat end hyperkeratosis in the herd. PMID:27210492

  14. 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.

  15. 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.

  16. INVESTIGATION OF SLURRY CUTOFF WALL DESIGN AND CONSTRUCTION METHODS FOR CONTAINING HAZARDOUS WASTES

    EPA Science Inventory

    The document reviews current design and construction methods of soil-bentonite slurry trench cutoff walls. It summarizes engineering practices, identifies areas of technical detail and initiates research to promote the development of standards for use of slurry walls to isolate h...

  17. 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.

  18. 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

    2015-12-01

    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.

  19. Analysis of Round Robin Test for Ultrasonic Thickness Measurement of Wall Thinned Pipe in Nuclear Power Plant

    NASA Astrophysics Data System (ADS)

    Lee, Dae-Hoon; Lee, Seung-Joon; Lee, Joon-Hyun; Lee, Sung-Ho

    2008-02-01

    It is well recognized that one of the most serious problems on the maintenance of piping system in Nuclear Power Plants (NPPs) is the wall thinning of carbon steel pipe components. The objective of this research is to verify confidence of wall thinning measurement system by conducting Round Robin Test (RRT). 23 specimens with different size and shape of pipe were used according to standard practice in RRT. The gage R&R analysis was introduced for each sigma quality level, so that repeatability and reproducibility can be estimated from RRT results.

  20. 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.

  1. 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.

  2. Measurements of core and compressed-shell temperature and density conditions in thick-wall target implosions at the OMEGA laser facility

    SciTech Connect

    Florido, R.; Mancini, R. C.; Nagayama, T.; Tommasini, R.; Delettrez, J. A.; Regan, S. P.; Yaakobi, B.

    2011-06-15

    A spectroscopic method is discussed to measure core and compressed-shell conditions in thick-wall plastic-shell implosions filled with deuterium and a tracer amount of argon. Simultaneous observation over a broad photon energy range of the argon line emission and the attenuation and self-emission effects of the compressed shell confining the core yields enough information to extract average temperature and density conditions in both core and compressed shell. The spectroscopic analysis also provides an estimate of the target areal density which is an important characteristic of inertial confinement fusion implosions.

  3. Coating of multi-walled carbon nanotube with SnO 2 films of controlled thickness and its application for Li-ion battery

    NASA Astrophysics Data System (ADS)

    Wang, Zhenyao; Chen, Ge; Xia, Dingguo

    Multi-walled carbon nanotubes (MWCNTs) coated with a smooth and uniform tin oxide (SnO 2) layers of different thickness were prepared by a novel thioglycolic acid assisted one-step wet chemical method. The coatings were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The thickness of the SnO 2 coatings can be easily controlled by changing the synthesis conditions, such as pH value of the solution and hydrolysis time. The electrochemical properties of the SnO 2/MWCNTs composites as anode materials for lithium batteries were studied by galvanostatic method. The composites showed high charge capacities and good durability against decay. This could be ascribed to the good dispersion, thin layer and small particle size of SnO 2 on MWCNTs.

  4. Relationship between the thickness of bronchial wall layers, emphysema score, and markers of remodeling in bronchoalveolar lavage fluid in patients with chronic obstructive pulmonary disease.

    PubMed

    Górka, Karolina; Soja, Jerzy; Jakieła, Bogdan; Plutecka, Hanna; Gross-Sondej, Iwona; Ćmiel, Adam; Mikrut, Sławomir; Łoboda, Piotr; Andrychiewicz, Anna; Jurek, Paulina; Sładek, Krzysztof

    2016-06-30

    INTRODUCTION    Airway remodeling plays an important role in the development of chronic obstructive pulmonary disease (COPD). Imaging methods, such as computed tomography (CT) and endobronchial ultrasound (EBUS), may be useful in the assessment of structural alterations in the lungs. OBJECTIVES    The aim of this study was to evaluate a relationship between the severity of emphysema assessed by chest CT, the thickness of bronchial wall layers measured by EBUS, and the markers of remodeling in bronchoalveolar lavage fluid (BALF) in patients with COPD. PATIENTS AND METHODS    The study included 33 patients with COPD who underwent pulmonary function tests, emphysema score assessment by chest CT, as well as bronchofiberoscopy with EBUS in order to measure the total bronchial wall thickness and, separately, layers L1, L2, and L3-5. Selected remodeling (matrix metalloproteinase 9 [MMP-9], tissue inhibitor of metalloproteinase 1, transforming growth factor β1 [TGF-β1]) and inflammatory markers (neutrophil elastase, eosinophil cationic protein) were measured in BALF samples using an enzyme-linked immunosorbent assay. RESULTS    MMP-9 levels in BALF were significantly higher in patients with very severe bronchial obstruction than in those with moderate and mild bronchial obstruction (P = 0.02), and showed a negative correlation with forced expiratory volume in 1 second (r = -0.538, P = 0.002). The thickness of L1 and L2, which histologically correspond to the mucosa, submucosa, and smooth muscle, demonstrated a positive correlation with TGF-β1 levels in BALF (r = 0.366, P = 0.046 and r = 0.425, P = 0.02) and the thickness of L1 showed a negative association with neutrophil elastase levels (r = -0.508, P = 0.004). There was no significant correlation between the analyzed markers in BALF and the emphysema score. CONCLUSIONS    Significant correlations of TGF-β1 and elastase with the thickness of bronchial wall layers, and of MMP-9 with the severity of

  5. Estimation of design sea ice thickness with maximum entropy distribution by particle swarm optimization method

    NASA Astrophysics Data System (ADS)

    Tao, Shanshan; Dong, Sheng; Wang, Zhifeng; Jiang, Wensheng

    2016-06-01

    The maximum entropy distribution, which consists of various recognized theoretical distributions, is a better curve to estimate the design thickness of sea ice. Method of moment and empirical curve fitting method are common-used parameter estimation methods for maximum entropy distribution. In this study, we propose to use the particle swarm optimization method as a new parameter estimation method for the maximum entropy distribution, which has the advantage to avoid deviation introduced by simplifications made in other methods. We conducted a case study to fit the hindcasted thickness of the sea ice in the Liaodong Bay of Bohai Sea using these three parameter-estimation methods for the maximum entropy distribution. All methods implemented in this study pass the K-S tests at 0.05 significant level. In terms of the average sum of deviation squares, the empirical curve fitting method provides the best fit for the original data, while the method of moment provides the worst. Among all three methods, the particle swarm optimization method predicts the largest thickness of the sea ice for a same return period. As a result, we recommend using the particle swarm optimization method for the maximum entropy distribution for offshore structures mainly influenced by the sea ice in winter, but using the empirical curve fitting method to reduce the cost in the design of temporary and economic buildings.

  6. 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.

  7. 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.

  8. Analysis and design of an ice wall framing system for an arctic drilling structure

    SciTech Connect

    Schlechten, J.R.; Bivens, H.R.; Dolan, D.K.; Fernandes, R.L.

    1984-05-01

    The exterior shell of a concrete base structure for an arctic oil drilling platform must be designed to resist extremely high local ice pressures. Stringent draft criteria for deployment of these structures in shallow waters require that the exterior shells, commonly called ice walls, have minimal weight in conjunction with maximum strength. These conflicting requirements are satisfactorily balanced by the selection of an arch shape on the interior face of the wall. This geometry induces arching action within the ice wall plate to resist ice loads in compression, thereby minimizing principal tension within the concrete. The development of principal tension in a concrete structure limits its ability to resist external forces. This paper describes the design of a prestressed concrete ice wall which satisfies these load, weight, and material constraints.

  9. High-flux first-wall design for a small reversed-field pinch reactor

    NASA Astrophysics Data System (ADS)

    Cort, G. E.; Graham, A. L.; Christensen, K. E.

    To achieve the goal of a commercially economical fusion power reactor, small physical size and high power density should be combined with simplicity (minimized use of high technology systems). The Reversed-Field Pinch (RFP) is a magnetic confinement device that promises to meet these requirements with power densities comparable to those in existing fission power plants. To establish feasibility of such an RFP reactor, a practical design for a first wall capable of withstanding high levels of cyclic neutron wall loadings is needed. Associated with the neutron flux in the proposed RFP reactor is a time averaged heat flux of 4.5 MW/sq m with a conservatively estimated transient peak approximately twice the average value. The design for a modular first wall made from a high-strength copper alloy that will meet these requirements of cyclic thermal loading is presented. The heat removal from the wall is by subcooled water flowing in straight tubes at high linear velocities.

  10. Gold-Based Cubic Nanoboxes with Well-Defined Openings at the Corners and Ultrathin Walls Less Than Two Nanometers Thick.

    PubMed

    Sun, Xiaojun; Kim, Junki; Gilroy, Kyle D; Liu, Jingyue; König, Tobias A F; Qin, Dong

    2016-08-23

    We report a facile synthesis of Au-based cubic nanoboxes as small as 20 nm for the outer edge length, together with well-defined openings at the corners and walls fewer than 10 atomic layers (or <2 nm) in thickness. The success relies on the selective formation of Ag2O at the corners of Ag nanocubes, followed by the conformal deposition of Au on the side faces in a layer-by-layer fashion. When six atomic layers of Au are formed on the side faces to generate Ag@Au6L core-shell nanocubes, we can selectively remove the Ag2O patches at the corner sites using a weak acid, making it possible to further remove the Ag core by H2O2 etching without breaking the ultrathin Au shell. This synthetic approach works well for Ag nanocubes of 38 and 18 nm in edge length, and the wall thickness of the nanoboxes can be controlled down to 2 nm. The resultant Au nanoboxes exhibit strong plasmonic absorption in the near-infrared region, consistent with computational simulations. PMID:27458731

  11. Novel technique for full-thickness resection of gastric malignancy: feasibility of nonexposed endoscopic wall-inversion surgery (news) in porcine models.

    PubMed

    Mitsui, Takashi; Goto, Osamu; Shimizu, Nobuyuki; Hatao, Fumihiko; Wada, Ikuo; Niimi, Keiko; Asada-Hirayama, Itsuko; Fujishiro, Mitsuihiro; Koike, Kazuhiko; Seto, Yasuyuki

    2013-12-01

    Full-thickness resection for gastric malignancy carries a risk of peritoneal dissemination due to opening of the gastric lumen. We evaluated the feasibility and safety a novel method of full-thickness resection without transmural communication, called nonexposed endoscopic wall-inversion surgery in ex vivo and in vivo porcine models. Six explanted porcine stomachs and 6 live pigs were used for this study. After marking and submucosal injection around 3 cm simulated lesions, the seromuscular layer was laparoscopically cut and sutured with the lesion inverted to the inside. Consecutively, a mucosubmucosal incision was made endoscopically. Three pigs used for the survival study were monitored for 7 days. All 12 lesions were successfully resected en bloc without perforation. The 3 pigs survived for 1 week without adverse events, and necropsy revealed neither leakage nor abscess formation related to the operation. We demonstrated nonexposed endoscopic wall-inversion surgery to be technically feasible and safe in both ex vivo and in vivo porcine studies. PMID:24300935

  12. 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.

  13. 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.

  14. 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.

  15. Design, Development, and Applications of Image Scanning Ellipsometry for the Measurement of Thin Film Thickness Profiles.

    NASA Astrophysics Data System (ADS)

    Liu, An-Hong

    experiments are expected. Moreover, since the initial draining film thickness is not infinite as assumed in the model, there is a difference between the real draining time and the model time. With calibration, this is not a hinderance to model evaluation. The present ISE design is not optimum but can be easily improved by redesigning and rebuilding the instrument. Suggestions for improvement include replacing the optical components for improved resolution, using better image acquisition hardware, and faster data analysis tools.

  16. Augmentation of Left Ventricular Wall Thickness With Alginate Hydrogel Implants Improves Left Ventricular Function and Prevents Progressive Remodeling in Dogs With Chronic Heart Failure

    PubMed Central

    Sabbah, Hani N.; Wang, Mengjun; Gupta, Ramesh C.; Rastogi, Sharad; Ilsar, Itamar; Sabbah, Michael S.; Kohli, Smita; Helgerson, Sam; Lee, Randall J.

    2013-01-01

    Objectives The study tested the hypothesis that augmentation of the left ventricular (LV) wall thickness with direct intramyocardial injections of alginate hydrogel implants (AHI) reduces LV cavity size, restores LV shape, and improves LV function in dogs with heart failure (HF). Background Progressive LV dysfunction, enlargement, and chamber sphericity are features of HF associated with increased mortality and morbidity. Methods Studies were performed in 14 dogs with HF produced by intracoronary microembolizations (LV ejection fraction [EF] <30%). Dogs were randomized to AHI treatment (n = 8) or to sham-operated control (n = 6). During an open-chest procedure, dogs received either intramyocardial injections of 0.25 to 0.35 ml of alginate hydrogel (Algisyl-LVR, LoneStar Heart, Inc., Laguna Hills, California) or saline. Seven injections were made ∼1.0 to 1.5 cm apart (total volume 1.8 to 2.1 ml) along the circumference of the LV free wall halfway between the apex and base starting from the anteroseptal groove and ending at the posteroseptal groove. Hemodynamic and ventriculographic measurements were made before treatment (PRE) and repeated post-surgery for up to 17 weeks (POST). Results Compared to control, AHI significantly reduced LV end-diastolic and end-systolic volumes and improved LV sphericity. AHI treatment significantly increased EF (26 ± 0.4% at PRE to 31 ± 0.4% at POST; p < 0.05) compared to the decreased EF seen in control dogs (27 ± 0.3% at PRE to 24 ± 1.3% at POST; p < 0.05). AHI treatment was well tolerated and was not associated with increased LV diastolic stiffness. Conclusions In HF dogs, circumferential augmentation of LV wall thickness with AHI improves LV structure and function. The results support continued development of AHI for the treatment of patients with advanced HF. PMID:23998003

  17. Constraints on target chamber first wall and target designs that will enable NIF debris shields to survive

    NASA Astrophysics Data System (ADS)

    Burnham, Alan K.; Gerassimenko, Michel; Scott, J. M.; Latkowski, Jeff F.; Whitman, Pamela K.; Genin, Francois Y.; Hibbard, Wilthea; Peterson, P. F.; Tokheim, R. E.; Curran, D. R.

    1999-07-01

    The NIF target chamber interior materials and target designs themselves have to be compatible with survival of the final- optics debris shields. To meet the planned maintenance and refinishing rate, the contamination of the debris shields cannot exceed about 1 nm equivalent thickness per shot of total material. This implies that he target mass must be limited to no more than 1 gram and the ablated mass released to the chamber from all other components must not exceed 3 grams. In addition, the targets themselves must either completely vaporize or send any minor amounts of shrapnel towards the chamber waist to prevent excessive catering of the debris shields. The constraints on the first-wall debris will remobilize at a rate fast enough to require cleaning every 3 weeks, about three times more frequent than possible with planned robotics. Furthermore, a comparison of ablatants from B4C and stainless-steel louvers suggest that remobilization of target debris by x-rays will be greater than that of the base material in both cases, thereby reducing the performance advantage of clean B4C over much cheaper stainless steel. Neutronics calculations indicate that activation of thin Ni-free stainless steel is not a significant source of maintenance personnel radiation dose. Consequently, the most attractive first wall design consists of stainless-steel louvers. Evaluation of various unconverted-light beam dump designs indicates that stainless steel louvers generate no more debris than other matrices, so one single design can serve as both first wall and beam dumps, eliminating beam steering restrictions caused by size and location of the beam dumps. One reservation is that the allowable contamination rate of the debris shield is not yet completely understood. Consequently, it is likely that either a protruding beam tube, a rapid post-shot gas purge of the final optics assembly, or thin polymeric pre-shield will be required to prevent low-velocity contamination from reaching

  18. Successful treatment of burn and visceral injury combined with full-thickness loss of the abdominal wall after blast injury.

    PubMed

    Başaran, Ozgür; Karaarslan, Pelin; Sakalloğlu, A Ebru; Kesik, Emine; Karakayalý, Hamdi; Haberal, Mehmet

    2006-01-01

    A 29-year-old man was admitted to our institution 10 days after he had undergone an urgent exploratory laparotomy at a local army hospital after a terrorist bombing attack. On admission, deep second-degree and third-degree burns involving 25% of the upper and lower extremities were present, together with a 25 x 10-cm abdominal full-thickness blast injury defect on the left side, an infected eviscerated midline incision, and a colostomy on the right side of the abdomen. The patient underwent a second laparotomy, at which time the intraabdominal abscess was drained, and the abdominal cavity was irrigated with saline. A jejunal perforation was found and sutured. The abdominal cavity was left open and covered with a Bogota bag for temporary closure. On postburn day 18, the patient underwent débridment and grafting of the third-degree burns to the left and right arm and right lower extremities. After several débridment sessions (postburn days 16, 18, 20, 22, and 24), an abdominal skin release and reapproximation were performed (postburn day 26). On postburn day 36, split-thickness skin grafts were placed directly on the granulated tissue of the intestines and on a defect in the left flank and iliac regions. Postoperatively, the patient did well. He was discharged on postburn day 78 with all wounds well healed. In our opinion, temporary closure followed by direct application of meshed split-thickness skin grafts to exposed abdominal viscera represents a simple method of reconstruction that can be safely performed, with minimal risk, on critically ill patients. PMID:16998411

  19. 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.

  20. 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.

  1. A Method for Cure Process Design of Thick Composite Components Manufactured by Closed Die Technology

    NASA Astrophysics Data System (ADS)

    Sorrentino, Luca; Tersigni, Luca

    2012-02-01

    During the manufacture of polymer-matrix composite components the cure degree must be uniform to have a good quality of the product. For thick composite components this condition is not often respected in fact the cure degree trend between the core and the external surface is different causing structural and geometrical/dimensional unconformities. In most cases, these problems are caused by a wrong design of cure process in terms of thermal cycle and tooling, therefore the cure cycle must be designed and optimized. The optimization of cure thermal cycle should include several performance criteria for the production system such as the targeted cure degree, the targeted maximum temperature of the part and the duration of the cure cycle as well as the production system limitations such as the maximum allowable heating rate, the maximum allowable cooling rate etc. This work aims to define by thermochemical phenomena a first step toward the definition of a method to optimize the cure degree of a thick composite components by focusing particular attention to the aspects of thermal degradations and residual stress.

  2. 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.

  3. 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.

  4. 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.

  5. Effects of Stent Design and Atherosclerotic Plaque Composition on Arterial Wall Biomechanics

    PubMed Central

    Timmins, Lucas H.; Meyer, Clark A.; Moreno, Michael R.; Moore, James E.

    2008-01-01

    Purpose: To examine the solid mechanical effects of varying stent design and atherosclerotic plaque stiffness on the biomechanical environment induced in a diseased artery wall model. Methods: Computational modeling techniques were employed to investigate the final radius of the lumen and artery wall stresses after stent implantation. Two stent designs were studied (one stiff and one less stiff). The stenotic artery was modeled as an axisymmetrical diseased vessel with a 20% stenosis by diameter. The material properties of the diseased tissue in the artery models varied. Atherosclerotic plaques half as stiff (0.5×), of equal stiffness (1.0×), or twice as stiff (2.0×) as the artery wall were investigated. Results: Final lumen radius was dependent on stent design, and the stiffer stent deformed the artery to an approximately 10% greater radius than the more compliant design. Alternatively, circumferential stress levels were dependent on both stent design and plaque material properties. Overall, the stiffer stent subjected the artery wall to much higher stress values than the more compliant design, with differences in peak values of 0.50, 0.31, and 0.09 MPa for the 2.0×, 1.0×, and 0.5× stiff plaques, respectively. Conclusion: Evidence suggests that a judicious choice of stent design can minimize stress while maintaining a patent lumen in stenotic arteries. If confronted with a rigid, calcified plaque, stent design is more important, as design differences can impose dramatically different stress fields, while still providing arterial patency. Alternatively, stent design is not as much of an issue when treating a soft, lipid-laden plaque, as stress fields do not vary significantly among stent designs. PMID:19090628

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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)

  11. 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

  12. 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%.

  13. 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. PMID:25749619

  14. Design of Highly Photofunctional Porous Polymer Films with Controlled Thickness and Prominent Microporosity.

    PubMed

    Gu, Cheng; Huang, Ning; Wu, Yang; Xu, Hong; Jiang, Donglin

    2015-09-21

    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

  15. 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

  16. 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.

  17. 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. PMID:9848879

  18. WALL-FIRED BOILER DESIGN CRITERIA FOR DRY SORBENT SO2 CONTROL WITH LOW NOX BURNERS

    EPA Science Inventory

    The report assesses the impact of Limestone Injection Multistage Burner (LIMB) technology on wall-fired utility boilers for both new and retrofit designs. Recent attention has focused on dry sorbent sulfur dioxide (SO2) control technology which, in conjunction with low-nitrogen-o...

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  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.

    2015-03-01

    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.

  9. Field Results for an Arctic AUV Designed for Characterizing Circulation and Ice Thickness

    NASA Astrophysics Data System (ADS)

    Bellingham, J. G.; Kirkwood, W. J.; Tervalon, N.; Cokelet, E.; Thomas, H.; Sibenac, M.; Gashler, D.; McEwen, R.; Henthorn, R.; Shane, F.; Osborn, D. J.; Johnson, K.; Overland, J.; Stein, P.; Bahlavouni, A.; Anderson, D.

    2002-12-01

    An Autonomous Underwater Vehicle designed for operation at high latitudes and under ice completed its first Arctic field tests from the USCGC Healy in fall of 2001. The ALTEX AUV has been under development since 1998, and is being created to provide: unprecedented endurance, ability to navigate at high latitudes, a depth rating of 1500 to 4500 meters depending on payload, and the capability to relay data through the ice to satellites via data buoys. The AUV's initial applications are focused on tracking the warm Atlantic Layer inflow - the primary source of seawater to the Arctic Ocean. Consequently the primary payloads are twin pumped CTD systems. Oxygen and nitrate sensors provide the ability to use NO as a tracer. An ice profiling sonar allows the AUV to estimate the ice thickness in real-time and is designed to generate high quality post-processed ice draft data comparable to that collected through the SCICEX program. The experiments in October aboard the USCGC Healy generated numerous water column and under-ice data sets. Traditional ship-based CTD operations were used to provide a comparison data set for AUV water column measurements. The post-processed ice draft results show reasonable ice profiles and have the potential, when combined with other science data collected, to shed some additional light on upper water column processes in ice-covered regions. Cruise results include: operating the AUV from the USCGC Healy in the ice pack, demonstrating inertial navigation system performance, obtaining oceanographic sections with the AUV, obtaining ice draft measurements with an AUV born sonar, and testing the data-buoy system. This work is supported by the National Science Foundation under grant NSF-OPP 9910290. The Packard Foundation and the Office of Naval Research have also provided support. The project was initiated under the National Ocean Partnership Program under contract N00014-98-1-0814.

  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. 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.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. 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. PMID:24958369

  18. 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.

  19. Optimal design of thin walled I beams for extreme natural frequency of torsional vibrations

    NASA Astrophysics Data System (ADS)

    Szymczak, C.

    1983-01-01

    The optimal design of thin-walled I beams so as to extremize the natural frequency of torsional vibration is considered. It is assumed that only one dimension of the cross-section, except for the web height, may be variable in given limits, along the axis of the beam. The optimality condition for the variable dimension is settled by means of Pontryagin's maximum principle. The effect of the constant, axial loads is also included. the solution of the problem formulated is generally found in an iterative way. Some numerical examples of optimization of the I beam with variable widt of flanges are given.

  20. Designing Beam Steering for Accurate Measurement of Intima-Media Thickness at Carotid Sinus

    NASA Astrophysics Data System (ADS)

    Mashiyama, Takashi; Hasegawa, Hideyuki; Kanai, Hiroshi

    2006-05-01

    Recently, cardiovascular disease has become the second most common cause of death in Japan following malignant neoplasm formation. Therefore, it is necessary to diagnose atherosclerosis during its early stages because atherosclerosis is one of the main causes of cardiovascular diseases. The carotid sinus is a site that is easily affected by atherosclerosis [C. K. Zarins et al.: Circ. Res. 53 (1983) 502]; therefore, the diagnosis of this disease at this site is important [S. C. Nicholls et al.: Stroke 20 (1989) 175]. However, it is difficult to accurately diagnose atherosclerosis in the carotid sinus in the long-axis plane, which is parallel to the axis of the vessel, using conventional linear scanning because the carotid sinus is not flat along the axis of the vessel, and the ultrasonic beams used in linear scanning are perpendicular to the arterial wall in a limited region. Echoes from regions that are not perpendicular to the ultrasonic beams are very weak and the arterial wall in such regions is hardly recognized in a B-mode image. In this study, the position of the arterial wall was predetermined on the basis of the B-mode image obtained by conventional linear scanning, then ultrasonic beams were transmitted again so that all beams were almost perpendicular to the arterial wall. In basic experiments, a nonflat object made of silicone rubber was measured and it was shown that it is possible to image a nonflat object over the entire scanned area using the proposed beam steering method. Furthermore, in in vivo experiments, the intima-media complex was imaged over the entire scanned area at the carotid sinus.

  1. 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.

  2. 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.

  3. Self-Assembling Peptide Coatings Designed for Highly Luminescent Suspension of Single-Walled Carbon Nanotubes

    PubMed Central

    Tsyboulski, Dmitri A.; Bakota, Erica L.; Witus, Leah S.; Rocha, John-David R.; Hartgerink, Jeffrey D.; Weisman, R. Bruce

    2009-01-01

    A series of self-assembling multidomain peptides have been designed, synthesized, and tested for their ability to individually suspend single-walled carbon nanotubes (SWCNTs) in water while preserving strong near-IR nanotube luminescence. Photometric and spectral measurements on individual SWCNTs revealed that emission in the common biocompatible coating agents Pluronic F127, ss-DNA, and BSA is approximately an order of magnitude weaker than in the bio-incompatible ionic surfactant SDBS. By contrast, one of the engineered peptides gave SWCNT emission ~40% as intense as in SDBS. A strong inverse correlation was also found between the spectral line widths of coated SWCNTs and the efficiency of their emission. Peptides with rationally designed self-assembly properties appear to be promising coatings that may enable SWCNT optical sensing applications in biological environments. PMID:19053447

  4. Plasma facing components: a conceptual design strategy for the first wall in FAST tokamak

    NASA Astrophysics Data System (ADS)

    Labate, C.; Di Gironimo, G.; Renno, F.

    2015-09-01

    Satellite tokamaks are conceived with the main purpose of developing new or alternative ITER- and DEMO-relevant technologies, able to contribute in resolving the pending issues about plasma operation. In particular, a high criticality needs to be associated to the design of plasma facing components, i.e. first wall (FW) and divertor, due to physical, topological and thermo-structural reasons. In such a context, the design of the FW in FAST fusion plant, whose operational range is close to ITER’s one, takes place. According to the mission of experimental satellites, the FW design strategy, which is presented in this paper relies on a series of innovative design choices and proposals with a particular attention to the typical key points of plasma facing components design. Such an approach, taking into account a series of involved physical constraints and functional requirements to be fulfilled, marks a clear borderline with the FW solution adopted in ITER, in terms of basic ideas, manufacturing aspects, remote maintenance procedure, manifolds management, cooling cycle and support system configuration.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Layer thickness and period as design parameters to tailor pyroelectric properties in ferroelectric superlattices

    SciTech Connect

    Misirlioglu, I. B.; Alpay, S. P.

    2014-10-27

    We theoretically examine the pyroelectric properties of ferroelectric-paraelectric superlattices as a function of layer thickness and configuration using non-linear thermodynamics coupled with electrostatic and electromechanical interactions between layers. We specifically study PbZr{sub 0.3}Ti{sub 0.7}O{sub 3}/SrTiO{sub 3} superlattices. The pyroelectric properties of such constructs consisting of relatively thin repeating units are shown to exceed the pyroelectric response of monolithic PbZr{sub 0.3}Ti{sub 0.7}O{sub 3} films. This is related to periodic internal electric fields generated due to the polarization mismatch between layers that allows tailoring of the shift in the transition temperature. Our results indicate that higher and electric field sensitive pyroresponse can be achieved from layer-by-layer engineered ferroelectric heterostructures.

  10. 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.

  11. 49 CFR 179.220-6 - Thickness of plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) The wall thickness, after forming of the inner container shell and 2:1 ellipsoidal heads must be not... thickness of plate in inches after forming. (b) The wall thickness after forming of the inner container... = Minimum thickness of plate in inches after forming. (c) The wall thickness after forming of...

  12. Numerical design and optimization of hydraulic resistance and wall shear stress inside pressure-driven microfluidic networks.

    PubMed

    Damiri, Hazem Salim; Bardaweel, Hamzeh Khalid

    2015-11-01

    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. Design of Tools for Press-countersinking or Dimpling 0.040-inch-thick-24S-T Sheet

    NASA Technical Reports Server (NTRS)

    Templin, R L; Fogwell, J W

    1942-01-01

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

  14. 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

  15. 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

  16. 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.

  17. 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.

  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. 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. PMID:25561459

  20. Effects of D-4F on Vasodilation and Vessel Wall Thickness in Hypercholesterolemic LDL Receptor Null and LDL receptor/ApoA-I Double Knockout Mice on Western Diet

    PubMed Central

    Ou, Jingsong; Wang, Jingli; Xu, Hao; Ou, Zhijun; Sorci-Thomas, Mary G.; Jones, Deron W.; Signorino, Paul; Densmore, John C.; Kaul, Sushma; Oldham, Keith T.; Pritchard, Kirkwood A.

    2005-01-01

    Previously we showed L-4F, a novel apolipoprotein A-I (apoA-I) mimetic, improved vasodilation in two dissimilar models of vascular disease; hypercholesterolemic low-density lipoprotein (LDL) receptor null (Ldlr −/−) mice and transgenic sickle cell disease mice. Here we determine the mechanisms by which D-4F improves vasodilation and arterial wall thickness in hypercholesterolemic Ldlr −/− mice and Ldlr −/−/apoA-I null (apoA-I −/−), double knockout mice. Ldlr −/− and Ldlr −/−/apoA-I −/− mice were fed western diet (WD) ± D-4F. Oral D-4F restored endothelium- and eNOS-dependent vasodilation in direct relationship to duration of treatments and reduced wall thickness in as little as 2 weeks in vessels with pre-existing disease in Ldlr −/− mice. D-4F had no effect on total or HDL cholesterol concentrations but reduced proinflammatory HDL levels. D-4F had no effect on plasma myeloperoxidase (MPO) concentrations but reduced MPO association with apoA-I as well as 3-nitrotyrosine in apoA-I. D-4F increased endothelium- and eNOS-dependent vasodilation in Ldlr −/−/apoA-I −/− mice but did not reduce wall thickness as it had in Ldlr −/− mice. Vascular endothelial cells were treated with 22-hydroxycholesterol (22-OHC) ± L-4F. 22-OHC decreased nitric oxide (•NO) and increased superoxide anion (O2 •−) production and increased ABCA-1 and collagen expression. L-4F restored •NO and O2 •− balance, had little effect on ABCA-1 expression but reduced collagen expression. These data demonstrate that although D-4F restores vascular endothelial cell and eNOS function to increase vasodilation, HDL containing apoA-I, or at least some critical concentration of the anti-atherogenic lipoprotein, is required for D-4F to decrease vessel wall thickness. PMID:16224061

  1. Secondary reconstruction with a transverse colon covered with a pectoralis major muscle flap and split thickness skin grafts for an esophageal defect and wide skin defects of the anterior chest wall.

    PubMed

    Sadanaga, Noriaki; Morinaga, Keigo; Matsuura, Hiroshi

    2015-12-01

    Necrosis of a reconstructed organ after esophagectomy is a rare postoperative complication. However, in case this complication develops, severe infectious complications can occur, and subsequent surgical reconstruction is quite complicated. To treat esophageal conduit necrosis after esophageal reconstruction with the terminal ileum and ascending colon, we reconstructed the esophagus using a transverse colon, which was covered with a pectoralis major muscle flap to reinforce the anastomotic site. In addition, split thickness skin grafts were applied to the wide skin defect to cover the reconstructed organs at the antesternal route. Widely extended split thickness skin grafts can adhere to the reconstructed organs without excessive tension. Therefore, this method enabled successful treatment of an esophageal defect and wide skin defects of the anterior chest wall. PMID:26943390

  2. 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.

  3. 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

  4. Wall shear stress as measured in vivo: consequences for the design of the arterial system

    PubMed Central

    Hoeks, Arnold P. G.

    2008-01-01

    Based upon theory, wall shear stress (WSS), an important determinant of endothelial function and gene expression, has been assumed to be constant along the arterial tree and the same in a particular artery across species. In vivo measurements of WSS, however, have shown that these assumptions are far from valid. In this survey we will discuss the assessment of WSS in the arterial system in vivo and present the results obtained in large arteries and arterioles. In vivo WSS can be estimated from wall shear rate, as derived from non-invasively recorded velocity profiles, and whole blood viscosity in large arteries and plasma viscosity in arterioles, avoiding theoretical assumptions. In large arteries velocity profiles can be recorded by means of a specially designed ultrasound system and in arterioles via optical techniques using fluorescent flow velocity tracers. It is shown that in humans mean WSS is substantially higher in the carotid artery (1.1–1.3 Pa) than in the brachial (0.4–0.5 Pa) and femoral (0.3–0.5 Pa) arteries. Also in animals mean WSS varies substantially along the arterial tree. Mean WSS in arterioles varies between about 1.0 and 5.0 Pa in the various studies and is dependent on the site of measurement in these vessels. Across species mean WSS in a particular artery decreases linearly with body mass, e.g., in the infra-renal aorta from 8.8 Pa in mice to 0.5 Pa in humans. The observation that mean WSS is far from constant along the arterial tree implies that Murray’s cube law on flow-diameter relations cannot be applied to the whole arterial system. Because blood flow velocity is not constant along the arterial tree either, a square law also does not hold. The exponent in the power law likely varies along the arterial system, probably from 2 in large arteries near the heart to 3 in arterioles. The in vivo findings also imply that in in vitro studies no average shear stress value can be taken to study effects on endothelial cells derived

  5. 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. PMID:26716256

  6. WASTE HANDLING BUILDING SHIELD WALL ANALYSIS

    SciTech Connect

    D. Padula

    2000-01-13

    The scope of this analysis is to estimate the shielding wall, ceiling or equivalent door thicknesses that will be required in the Waste Handling Building to maintain the radiation doses to personnel within acceptable limits. The shielding thickness calculated is the minimum required to meet administrative limits, and not necessarily what will be recommended for the final design. The preliminary evaluations will identify the areas which have the greatest impact on mechanical and facility design concepts. The objective is to provide the design teams with the necessary information to assure an efficient and effective design.

  7. Study of PET scanner designs using clinical metrics to optimize the scanner axial FOV and crystal thickness

    NASA Astrophysics Data System (ADS)

    Surti, S.; Werner, M. E.; Karp, J. S.

    2013-06-01

    The aim of this study is to understand the trade-off between crystal thickness and scanner axial field-of-view FOV (AFOV) for clinical PET imaging. Clinical scanner design has evolved towards 20-25 mm thick crystals and 16-22 cm long scanner AFOV, as well as time-of-flight (TOF) imaging. While Monte Carlo studies demonstrate that longer AFOV and thicker crystals will lead to higher scanner sensitivity, cost has prohibited the building of commercial scanners with >22 cm AFOV. In this study, we performed a series of system simulations to optimize the use of a given amount of crystal material by evaluating the impact on system sensitivity and noise equivalent counts (NEC), as well as image quality in terms of lesion detectability. We evaluated two crystal types (LSO and LaBr3) and fixed the total crystal volume used for each type (8.2 L of LSO and 17.1 L of LaBr3) while varying the crystal thickness and scanner AFOV. In addition, all imaging times were normalized so that the total scan time needed to scan a 100 cm long object with multiple bed positions was kept constant. Our results show that the highest NEC cm-1 in a 35 cm diameter ×70 cm long line source cylinder is achieved for an LSO scanner with 10 mm long crystals and AFOV of 36 cm, while for LaBr3 scanners, the highest NEC cm-1 is obtained with 20 mm long crystals and an AFOV of 38 cm. Lesion phantom simulations show that the best lesion detection performance is achieved in scanners with long AFOV (≥36 cm) and using thin crystals (≤10 mm of LSO and ≤20 mm of LaBr3). This is due to a combination of improved NEC, as well as improved lesion contrast estimation due to better spatial resolution in thinner crystals. Alternatively, for lesion detection performance similar to that achieved in standard clinical scanner designs, the long AFOV scanners can be used to reduce the total scan time without increasing the amount of crystal used in the scanner. In addition, for LaBr3 based scanners, the reduced lesion

  8. Investigating shoulder muscle loading and exerted forces during wall painting tasks: influence of gender, work height and paint tool design.

    PubMed

    Rosati, Patricia M; Chopp, Jaclyn N; Dickerson, Clark R

    2014-07-01

    The task of wall painting produces considerable risk to the workers, both male and female, primarily in the development of upper extremity musculoskeletal disorders. Insufficient information is currently available regarding the potential benefits of using different paint roller designs or the possible adverse effects of painting at different work heights. The aim of this study was to investigate the influence of gender, work height, and paint tool design on shoulder muscle activity and exerted forces during wall painting. Ten young adults, five male and five female, were recruited to perform simulated wall painting at three different work heights with three different paint roller designs while upper extremity muscle activity and horizontal push force were recorded. Results demonstrated that for female participants, significantly greater total average (p = 0.007) and integrated (p = 0.047) muscle activity was present while using the conventional and curly flex paint roller designs compared to the proposed design in which the load was distributed between both hands. Additionally, for both genders, the high working height imposed greater muscular demands compared to middle and low heights. These findings suggest that, if possible, avoid painting at extreme heights (low or high) and that for female painters, consider a roller that requires the use of two hands; this will reduce fatigue onset and subsequently mitigate potential musculoskeletal shoulder injury risks. PMID:24636728

  9. Dynamic 3D printed titanium copy prosthesis: a novel design for large chest wall resection and reconstruction

    PubMed Central

    Pérez Méndez, Itzell

    2016-01-01

    Due to high rates of complications, chest wall resection and reconstruction is a high risk procedure when large size of resection is required. Many different prosthetic materials have been used with similar results. Recently, thanks to the new advances in technology, personalized reconstruction have been possible with specific custom-made prosthesis. Nevertheless, they all generate certain amount of stiffness in thoracic motion because of his rigidity. In this report, we present a forward step in prosthesis design based on tridimensional titanium-printed technology. An exact copy of the resected chest wall was made, even endowing simulated sternochondral articulations, to achieve the most exact adaptation and best functional results, with a view to minimize postoperative complications. This novel design, may constitute an important step towards the improvement of the functional postoperative outcomes compared to the other prosthesis, on the hope, to reduce postoperative complications. PMID:27293863

  10. Dynamic 3D printed titanium copy prosthesis: a novel design for large chest wall resection and reconstruction.

    PubMed

    Aragón, Javier; Pérez Méndez, Itzell

    2016-06-01

    Due to high rates of complications, chest wall resection and reconstruction is a high risk procedure when large size of resection is required. Many different prosthetic materials have been used with similar results. Recently, thanks to the new advances in technology, personalized reconstruction have been possible with specific custom-made prosthesis. Nevertheless, they all generate certain amount of stiffness in thoracic motion because of his rigidity. In this report, we present a forward step in prosthesis design based on tridimensional titanium-printed technology. An exact copy of the resected chest wall was made, even endowing simulated sternochondral articulations, to achieve the most exact adaptation and best functional results, with a view to minimize postoperative complications. This novel design, may constitute an important step towards the improvement of the functional postoperative outcomes compared to the other prosthesis, on the hope, to reduce postoperative complications. PMID:27293863

  11. Experimental investigation of a 10-percent-thick helicopter rotor airfoil section designed with a viscous transonic analysis code

    NASA Technical Reports Server (NTRS)

    Noonan, K. W.

    1981-01-01

    An investigation was conducted in the Langley 6- by 28-Inch Transonic Tunnel to determine the two dimensional aerodynamic characteristics of a 10-percent-thick helicopter rotor airfoil at Mach numbers from 0.33 to 0.87 and respective Reynolds numbers from 4.9 x 10 to the 6th to 9.8 x 10 to the 6th. This airfoil, designated the RC-10(N)-1, was also investigated at Reynolds numbers from 3.0 x 10 to the 6th to 7.3 x 10 to the 6th at respective Mach numbers of 0.33 to 0.83 for comparison wit the SC 1095 (with tab) airfoil. The RC-10(N)-1 airfoil was designed by the use of a viscous transonic analysis code. The results of the investigation indicate that the RC-10(N)-1 airfoil met all the design goals. At a Reynolds number of about 9.4 x 10 to the 6th the drag divergence Mach number at zero normal-force coefficient was 0.815 with a corresponding pitching-moment coefficient of zero. The drag divergence Mach number at a normal-force coefficient of 0.9 and a Reynolds number of about 8.0 x 10 to the 6th was 0.61. The drag divergence Mach number of this new airfoil was higher than that of the SC 1095 airfoil at normal-force coefficients above 0.3. Measurements in the same wind tunnel at comparable Reynolds numbers indicated that the maximum normal-force coefficient of the RC-10(N)-1 airfoil was higher than that of the NACA 0012 airfoil for Mach numbers above about 0.35 and was about the same as that of the SC 1095 airfoil for Mach numbers up to 0.5.

  12. Longitudinal displacement of the carotid wall and cardiovascular risk factors: associations with aging, adiposity, blood pressure and periodontal disease independent of cross-sectional distensibility and intima-media thickness.

    PubMed

    Zahnd, Guillaume; Vray, Didier; Sérusclat, André; Alibay, Djhianne; Bartold, Mark; Brown, Alex; Durand, Marion; Jamieson, Lisa M; Kapellas, Kostas; Maple-Brown, Louise J; O'Dea, Kerin; Moulin, Philippe; Celermajer, David S; Skilton, Michael R

    2012-10-01

    The recently discovered longitudinal displacement of the common carotid arterial wall (i.e., the motion along the same plane as the blood flow), may be associated with incident cardiovascular events and represents a novel and relevant clinical information. At present, there have only been a few studies that have been conducted to investigate this longitudinal movement. We propose here a method to assess noninvasively the wall bi-dimensional (two-dimensional [2-D], cross-sectional and longitudinal) motion and present an original approach that combines a robust speckle tracking scheme to guidance by minimal path contours segmentation. Our method is well suited to large clinical population studies as it does not necessitate strong imaging prerequisites. The aim of this study is to describe the association between the longitudinal displacement of the carotid arterial wall and cardiovascular risk factors, among which periodontal disease. Some 126 Indigenous Australians with periodontal disease, an emerging risk factor, and 27 healthy age- and sex-matched non-indigenous control subjects had high-resolution ultrasound scans of the common carotid artery. Carotid intima-media thickness and arterial wall 2-D motion were then assessed using our method in ultrasound B-mode sequences. Carotid longitudinal displacement was markedly lower in the periodontal disease group than the control group (geometric mean (IQR): 0.15 mm (0.13) vs. 0.42 mm (0.30), respectively; p < 0.0001), independent of cardiovascular risk factors, cross-sectional distensibility and carotid intima-media thickness (p < 0.0001). A multivariable model indicated that the strongest correlates of carotid longitudinal displacement in adults with periodontal disease were age (β-coefficient = -.235, p = .03), waist (β-coefficient = -.357, p = 0.001), and pulse pressure (β-coefficient = .175, p = 0.07), independent of other cardiovascular risk factors, cross-sectional distensibility and pulse wave velocity. Carotid

  13. Prediction of Residual Stress Distributions in Welded Sections of P92 Pipes with Small Diameter and Thick Wall based on 3D Finite Element Simulation

    NASA Astrophysics Data System (ADS)

    Wang, Xiaowei; Gong, Jianming; Zhao, Yanping; Wang, Yanfei

    2015-05-01

    This study used ABAQUS finite element (FE) software to investigate the residual stress distributions of P92 welded pipes in both the as-weld and post weld heat treated (PWHT) condition. Sequential coupling quasi-static thermo-mechanical in conjunction with moving double ellipsoidal heat source and an element add/remove technique to simulate deposition of new weld material, are combined in the 3D FE analysis. To validate the simulation results, the residual stresses in axial direction at the surface of pipe were measured by X-ray diffraction technique and compared with the results of FE analysis. Detailed characteristic distributions of the residual stresses are discussed. Results show that the FE model can predict the residual stress distributions satisfactorily. Highest residual stresses on the outer surface are found in the last weld bead to be deposited. And the highest tensile residual stress for the full welded section take place in heat affected zone (HAZ) near the middle thickness. Larger residual sstress can be found around the welding start point along the pipe circumference. Comparison of heat treated specimen and untreated specimen illustrates that PWHT has a strong effect on the residual stress field.

  14. Development of two supercritical airfoils with a thickness-to-chord ratio of 0.20 and design lift coefficients of 0.3 and 0.4

    NASA Technical Reports Server (NTRS)

    Jernell, L. S.

    1976-01-01

    Two supercritical airfoils were developed specifically for application to span distributed loading cargo aircraft. These airfoils have a thickness-to-chord ratio of 0.20 and design lift coefficients of 0.3 and 0.4, and were derived by modifying a recently developed supercritical airfoil having a thickness-to-chord ratio of 0.18 and a design lift coefficient of 0.5. The aerodynamic characteristics were calculated using a theoretical method which computes the flow field about an airfoil having supercritical surface velocities.

  15. Mullite Plasma Spraying for In Situ Repair of Cracks in Mullite Refractories: Simultaneous Optimization of Porosity and Thickness by Statistical Design of Experiments

    NASA Astrophysics Data System (ADS)

    Schrijnemakers, A.; Francq, B. G.; Cloots, R.; Vertruyen, B.; Boschini, F.

    2013-10-01

    We report a laboratory-scale study about the suitability of the plasma spraying process for "in situ" repair of cracks in mullite refractories of industrial furnaces. The "design of experiments" approach is used to investigate how the coating porosity and thickness are influenced by six experimental parameters. Arc current, secondary gas (H2) flow rate, and stand-off distance are the most significant parameters for both responses. Several interaction terms also affect significantly the thickness response. The validity of the model equations is discussed both from a statistical point of view and regarding the physical credibility of the main model terms. Additional experiments confirm that the measured properties lie into the prediction intervals provided by the model. Using a set of parameters optimized for minimal porosity and high thickness (relevant for the crack repair application), coatings with 6% porosity and 1070 μm thickness can be prepared reproducibly.

  16. Design of a parallel transmit head coil at 7T with magnetic wall distributed filters.

    PubMed

    Connell, Ian R O; Gilbert, Kyle M; Abou-Khousa, Mohamed A; Menon, Ravi S

    2015-04-01

    Ultra-high field magnetic resonance imaging (MRI) scanners ( ≥ 7T) require radio-frequency (RF) coils to operate in the range of the electromagnetic spectrum where the effective wavelength in the tissue approaches the patient dimensions. Multi-channel transmit arrays, driven in parallel, have been developed to increase the transmit field (B1(+)) uniformity in this wavelength regime. However, the closely packed array elements interact through mutual coupling. This paper expands on the ability of a distributed planar filter (the "magnetic wall") to decouple individual elements in an entire array. A transmit RF coil suitable for neuroimaging at 7T was constructed. The transmit coil, composed of 10 individual surface coil elements, was decoupled with magnetic walls. A separate receive coil array was used for signal reception. The hardware and imaging performance of the transmit coil was validated with electromagnetic simulation, bench-top measurements, and in vivo MRI experiments. Analysis and measurements confirmed that the magnetic wall decoupling method provides high isolation between transmit channels, while minimally affecting the B1(+) field profiles. Electromagnetic simulations confirmed that the decoupling method did not correlate to local specific absorption rate (SAR) "hot spots" or increase local-to-global SAR fractions in comparison to previously reported 7T multi-channel transmit arrays employing different decoupling methods. PMID:25415982

  17. BUMPERII - DESIGN ANALYSIS CODE FOR OPTIMIZING SPACECRAFT SHIELDING AND WALL CONFIGURATION FOR ORBITAL DEBRIS AND METEOROID IMPACTS

    NASA Technical Reports Server (NTRS)

    Hill, S. A.

    1994-01-01

    of penetration values per surface area for each element in the model. The SHIELD module writes this data file in either SUPERTAB Universal File Format or PATRAN Neutral File Format so threat contour plots can be generated as a post-processing feature of the FEM programs SUPERTAB and PATRAN. The CONTOUR module combines the functions of the RESPONSE module and most of the SHIELD module functions allowing determination of ranges of PNP's by looping over ranges of shield and/or wall thicknesses. A data file containing the PNP's for the corresponding shield and vessel wall thickness is produced. Users may perform sensitivity studies of two kinds. The effects of simple variations in orbital time, surface area, and flux may be analyzed by making changes to the terms in the equation representing the average number of penetrating particles per unit time in the PNP solution equation. The package analyzes other changes, including model environment, surface area, and configuration, by re-running the solution sequence with new GEOMETRY and RESPONSE data. BUMPERII can be run with no interactive output to the screen during execution. This can be particularly useful during batch runs. BUMPERII is written in FORTRAN 77 for DEC VAX series computers running under VMS, and was written for use with the finite-element model code SUPERTAB or PATRAN as both a pre-processor and a post-processor. Use of an alternate FEM code will require either development of a translator to change data format or modification of the GEOMETRY subroutine in BUMPERII. This program is available in DEC VAX BACKUP format on a 9-track 1600 BPI magnetic tape (standard distribution media) or on TK50 tape cartridge. The original BUMPER code was developed in 1988 with the BUMPERII revisions following in 1991 and 1992. SUPERTAB is a former name for I-DEAS. I-DEAS Finite Element Modeling is a trademark of Structural Dynamics Research Corporation. DEC, VAX, VMS and TK50 are trademarks of Digital Equipment Corporation.

  18. Measuring Thicknesses of Wastewater Films

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Davenport, R. J.

    1987-01-01

    Sensor determines when thickness of film of electrically conductive wastewater on rotating evaporator drum exceeds preset value. Sensor simple electrical probe that makes contact with liquid surface. Made of materials resistant to chemicals in liquid. Mounted on shaft in rotating cylinder, liquid-thickness sensor extends toward cylinder wall so tip almost touches. Sensor body accommodates probe measuring temperature of evaporated water in cylinder.

  19. Cortical thickness correlates of psychotic experiences: examining the effect of season of birth using a genetically informative design.

    PubMed

    Córdova-Palomera, A; Alemany, S; Falcón, C; Bargalló, N; Goldberg, X; Crespo-Facorro, B; Nenadic, I; Fañanás, L

    2014-09-01

    Season of birth has been shown to influence risk for several neuropsychiatric diseases. Furthermore, it has been suggested that season of birth modifies a number of brain morphological traits. Since cortical thickness alterations have been reported across some levels of the psychosis-spectrum, this study was aimed at i) assessing the scarcely explored relationship between cortical thickness and severity of subclinical psychotic experiences (PEs) in healthy subjects, and ii) evaluating the potential impact of season of birth in the preceding thickness-PEs relationship. As both PEs and brain cortical features are heritable, the current work used monozygotic twins to separately evaluate familial and unique environmental factors. High-resolution structural MRI scans of 48 twins (24 monozygotic pairs) were analyzed to estimate cortical thickness using FreeSurfer. They were then examined in relation to PEs, accounting for the effects of birth season; putative differential relationships between PEs and cortical thickness depending on season of birth were also tested. Current results support previous findings indicative of cortical thickening in healthy individuals with high psychometrically assessed psychosis scores, probably in line with theories of compensatory aspects of brain features in non-clinical populations. Additionally, they suggest distinct patterns of cortical thickness-PEs relationships depending on birth seasonality. Familial factors underlying the presence of PEs may drive these effects. PMID:24923523

  20. 49 CFR 179.220-6 - Thickness of plates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-6 Thickness of plates. (a) The wall... after forming. (b) The wall thickness after forming of the inner container heads, if flanged and dished... plate in inches after forming. (c) The wall thickness after forming of the cylindrical section and...

  1. In vitro, time-resolved PIV comparison of the effect of stent design on wall shear stress.

    PubMed

    Charonko, John; Karri, Satyaprakash; Schmieg, Jaime; Prabhu, Santosh; Vlachos, Pavlos

    2009-07-01

    The effect of stent design on wall shear stress (WSS) and oscillatory shear index (OSI) was studied in vitro using time-resolved digital particle image velocimetry (DPIV). Four drug-eluting stents [XIENCE V (Abbott Vascular), TAXUS Liberté (Boston Scientific), Endeavor (Medtronic), and Cypher (J&J Cordis)] and a bare-metal stent [VISION (Abbott Vascular)] were implanted into compliant vessel models, and the flow was measured in physiologically accurate coronary conditions featuring reversal and realistic offsets between pressure and flowrate. DPIV measurements were made at three locations under two different flow rates (resting: Re = 160, f = 70 bpm and exercise: Re = 300, f = 120 bpm). It was observed that design substantially affected the WSS experienced at the vessel walls. Averaged values between struts ranged from 2.05 dynes/cm(2) (Cypher) to 8.52 dynes/cm(2) (XIENCE V) in resting conditions, and from 3.72 dynes/cm(2) (Cypher) to 14.66 dynes/cm(2) (VISION) for the exercise state. Within the stent, the WSS dropped and the OSI increased immediately distal to each strut. In addition, an inverse correlation between average WSS and OSI existed. Comparisons with recently published results from animal studies show strong correlation between the measured WSS and observed endothelial cell coverage. These results suggest the importance of stent design on the WSS experienced by endothelial cells in coronary arteries. PMID:19381810

  2. Longitudinal emittance: An introduction to the concept and survey of measurement techniques including design of a wall current monitor

    SciTech Connect

    Webber, R.C.

    1990-03-01

    The properties of charged particle beams associated with the distribution of the particles in energy and in time can be grouped together under the category of longitudinal emittance. This article is intended to provide an intuitive introduction to the concepts longitudinal emittance; to provide an incomplete survey of methods used to measure this emittance and the related properties of bunch length and momentum spread; and to describe the detailed design of a 6 Ghz bandwidth resistive wall current monitor useful for measuring bunch shapes of moderate to high intensity beams. Overall, the article is intended to be broad in scope, in most cases deferring details to cited original papers. 37 refs., 21 figs.

  3. Numerical method for determining the allowable medium temperature during transient operation of a thick-walled boiler element in power plant

    NASA Astrophysics Data System (ADS)

    Rząsa, Dariusz; Duda, Piotr

    2011-12-01

    Secure and cost-effective power generation has become very important nowdays. Care must be taken while designing and operating modern steam power plants. There are regulations such as German boiler regulations (Technische Regeln für Dampfkessel 301) or European Standards that guide the user how to operate the steam power plants. However, those regulations are based on the quasi-steady state assumption and one dimensional temperature distribution in the entire element. This simplifications may not guarantee that the heating and cooling operations are conducted in the most efficient way. Thus, it was important to find an improved method that can allow to establish optimum parameters for heating and cooling operations. The optimum parameters should guarantee that the maximum total stresses in the construction element are in the allowable limits and the entire process is conducted in the shortest time. This paper summarizes mathematical descriptions how to optimize shut down process of power block devices. The optimization formulation is based on the assumption that the maximum total stresses in the whole construction element should be kept within allowable limits during cooling operation. Additionally, the operation should be processed in the shortest time possible.

  4. Thin Wall Iron Castings

    SciTech Connect

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  5. Design, development, and construction of the Phobos time-of-flight walls, and studies of gold+gold collisions at RHIC energies using the time-of-flight walls

    NASA Astrophysics Data System (ADS)

    Johnson, Erik Bjorn

    The Phobos Time of Flight (TOF) Walls were designed and constructed at the University of Rochester. The TOF walls were designed as a cost-effective system, and the design and construction process is laid out in detail in this text. The average intrinsic time resolution of the TOF walls' scintillators is 80 ps. The TOF walls were installed in Phobos and commissioned prior to the data run of Au+Au collisions at SNN = 130 GeV. Particles can be tracked to the TOF walls with a 12.8:1 signal to background ratio. The walls are shown to have an overall timing resolution ˜200 ps, which doubles the momentum region over which particles can be identified as compared to the Phobos spectrometer. The TOF walls were used to understand RHIC collisions by studying the charged-particle multiplicity and the antiproton to proton, p¯/p, ratio. The charged-particle multiplicity was measured for Au+Au collisions at SNN = 19.6, 130, and 200 GeV. For the 6% most central events, the scaled charged-particle multiplicities, (1/<0.5*Npart>)*dN/deta |eta|<1, for these three collision energies are 1.9 +/- 0.2, 3.1 +/- 0.3, and 3.6 +/- 0.4, respectively. The scaled charged-particle multiplicity and the fraction of hard processes involved in particle production increase with the collision energy. The p¯/p ratio is constant with respect to the collision centrality (Npart > 50) and the transverse momentum (pT < 1.8 GeV/c). For rapidity, y < 1, pT < 1.8 GeV/c and Npart > 50, the / ratio is 0.71 +/- 0.01(stat.) +/- 0.02(syst.).

  6. A study of 3D aerodynamic design for a transonic compressor blading optimized by the locations of aerofoil maximum thickness and maximum camber

    NASA Astrophysics Data System (ADS)

    Chen, Naixing; Zhang, Hongwu; Xu, Yanji; Huang, Weiguang

    2003-08-01

    A design procedure for improving the efficiency of a transonic compressor blading was proposed based on a rapid generation method for three-dimensional blade configuration and computational meshes, a three-dimensional Navier-Stokes solver and an optimization approach. The objective of the present paper is to design a transonic compressor blading optimized only by selection of the locations of maximum camber and maximum thickness for the airfoils at different span heights and to study how do these two design parameters affect the blade performance. The blading configuration and the computational meshes can be obtained very rapidly for any given combination of maximum camber and maximum thickness. The computational grid system generated is used for the Navier-Stokes solution to predict adiabatic efficiency, total pressure ratio and flow rate. As a main result of the optimization, adiabatic efficiency was successfully improved.

  7. Molecular design of strong single-wall carbon nanotube/polyelectrolyte multilayer composites

    NASA Astrophysics Data System (ADS)

    Mamedov, Arif A.; Kotov, Nicholas A.; Prato, Maurizio; Guldi, Dirk M.; Wicksted, James P.; Hirsch, Andreas

    2002-11-01

    The mechanical failure of hybrid materials made from polymers and single-wall carbon nanotubes (SWNT) is primarily attributed to poor matrix-SWNT connectivity and severe phase segregation. Both problems can be successfully mitigated when the SWNT composite is made following the protocol of layer-by-layer assembly. This deposition technique prevents phase segregation of the polymer/SWNT binary system, and after subsequent crosslinking, the nanometre-scale uniform composite with SWNT loading as high as 50 wt% can be obtained. The free-standing SWNT/polyelectrolyte membranes delaminated from the substrate were found to be exceptionally strong with a tensile strength approaching that of hard ceramics. Because of the lightweight nature of SWNT composites, the prepared free-standing membranes can serve as components for a variety of long-lifetime devices.

  8. Assessment of the impact of degraded shear wall stiffnesses on seismic plant risk and seismic design loads

    SciTech Connect

    Klamerus, E.W.; Bohn, M.P.; Johnson, J.J.; Asfura, A.P.; Doyle, D.J.

    1994-02-01

    Test results sponsored by the USNRC have shown that reinforced shear wall (Seismic Category I) structures exhibit stiffnesses and natural frequencies which are smaller than those calculated in the design process. The USNRC has sponsored Sandia National Labs to perform an evaluation of the effects of the reduced frequencies on several existing seismic PRAs in order to determine the seismic risk implications inherent in these test results. This report presents the results for the re-evaluation of the seismic risk for three nuclear power plants: the Peach Bottom Atomic Power Station, the Zion Nuclear Power Plant, and Arkansas Nuclear One -- Unit 1 (ANO-1). Increases in core damage frequencies for seismic initiated events at Peach Bottom were 25 to 30 percent (depending on whether LLNL or EPRI hazard curves were used). At the ANO-1 site, the corresponding increases in plant risk were 10 percent (for each set of hazard curves). Finally, at Zion, there was essentially no change in the computed core damage frequency when the reduction in shear wall stiffness was included. In addition, an evaluation of deterministic ``design-like`` structural dynamic calculations with and without the shear stiffness reductions was made. Deterministic loads calculated for these two cases typically increased on the order of 10 to 20 percent for the affected structures.

  9. Designer's guidebook for first wall/blanket/shield assembly, maintenance, and repair

    SciTech Connect

    Not Available

    1983-12-30

    This is the initial issue of the guidebook. Since a guidebook of this type must incorporate information concerning a wide range of subjects, much additional data will eventually be included. The guidebook will document, in summary and easily referenceable form, data, designs, design concepts, design guidelines and background information useful to the FWBS and to the Maintenance System designer. In providing guidelines for the AMR of the FWBS, the guidebook must, of necessity, include guidelines for all aspects of maintenance associated with the FWBS. These include most maintenance operations within the reactor room necessary to gain access, identify faults, and handle equipment related to FWBS maintenance. In addition, the guidelines include those required to define facility requirements for handling and repair of FWBS and related reactor components external to the reactor room. Particular emphasis is given to remote maintenance design and operations.

  10. Lead Thickness Measurements

    SciTech Connect

    Rucinski, R.; /Fermilab

    1998-02-16

    The preshower lead thickness applied to the outside of D-Zero's superconducting solenoid vacuum shell was measured at the time of application. This engineering documents those thickness measurements. The lead was ordered in sheets 0.09375-inch and 0.0625-inch thick. The tolerance on thickness was specified to be +/- 0.003-inch. The sheets all were within that thickness tolerance. The nomenclature for each sheet was designated 1T, 1B, 2T, 2B where the numeral designates it's location in the wrap and 'T' or 'B' is short for 'top' or 'bottom' half of the solenoid. Micrometer measurements were taken at six locations around the perimeter of each sheet. The width,length, and weight of each piece was then measured. Using an assumed pure lead density of 0.40974 lb/in{sup 3}, an average sheet thickness was calculated and compared to the perimeter thickness measurements. In every case, the calculated average thickness was a few mils thinner than the perimeter measurements. The ratio was constant, 0.98. This discrepancy is likely due to the assumed pure lead density. It is not felt that the perimeter is thicker than the center regions. The data suggests that the physical thickness of the sheets is uniform to +/- 0.0015-inch.

  11. Design of an Improved Heater Array to Measure Microscale Wall Heat Transfer

    NASA Technical Reports Server (NTRS)

    Kim, Jungho; Chng, Choon Ping; Kalkur, T. S.

    1996-01-01

    An improved array of microscale heaters is being developed to measure the heat transfer coefficient at many points underneath individual bubbles during boiling as a function of space and time. This heater array enables the local heat transfer from a surface during the bubble growth and departure process to be measured with very high temporal and spatial resolution, and should allow better understanding of the boiling heat transfer mechanisms by pin-pointing when and where in the bubble departure cycle large amounts of wall heat transfer occur. Such information can provide much needed data regarding the important heat transfer mechanisms during the bubble departure cycle, and can serve as benchmarks to validate many of the analytical and numerical models used to simulate boiling. The improvements to the heater array include using a silicon-on-quartz substrate to reduce thermal cross-talk between the heaters, decreased space between the heaters, increased pad sizes on the heaters, and progressive heater sizes. Some results using the present heater array are discussed.

  12. Development of a clickable designer monolignol for interrogation of lignification in plant cell walls.

    PubMed

    Bukowski, Natalie; Pandey, Jyotsna L; Doyle, Lucas; Richard, Tom L; Anderson, Charles T; Zhu, Yimin

    2014-12-17

    Lignin is an abundant and essential polymer in land plants. It is a prime factor in the recalcitrance of lignocellulosic biomass to agricultural and industrial end-uses such as forage, pulp and papermaking, and biofuels. To better understand lignification at the molecular level, we are developing a lignin spectroscopic and imaging toolbox on one "negligible" auxiliary. Toward that end, we describe the design, synthesis, and characterization of a new designer monolignol, 3-O-propargylcaffeyl alcohol, which contains a bioorthogonal alkynyl functional group at the 3-O-position. Importantly, our data indicate that this monolignol does not alter the fidelity of lignification. We demonstrate that the designer monolignol provides a platform for multiple spectroscopic and imaging approaches to reveal temporal and spatial details of lignification, the knowledge of which is critical to reap the potential of energy-rich renewable plant biomass for sustainable liquid fuels and other diverse economic applications. PMID:25405515

  13. Design and implementation of an integral wall-mounted quartz crystal microbalance for atomic layer deposition.

    PubMed

    Riha, Shannon C; Libera, Joseph A; Elam, Jeffrey W; Martinson, Alex B F

    2012-09-01

    Quartz crystal microbalance (QCM) measurements have played a vital role in understanding and expediting new atomic layer deposition (ALD) processes; however, significant barriers remain to their routine use and accurate execution. In order to turn this exclusively in situ technique into a routine characterization method, an integral QCM fixture was developed. This new design is easily implemented on a variety of chemical vapor deposition (CVD) tools, allows rapid sample exchange, prevents backside deposition, and minimizes both the footprint and flow disturbance. Unlike previous QCM designs, the fast thermal equilibration enables tasks such as temperature-dependent studies and ex situ sample exchange, further highlighting the utility of this QCM design for day-to-day use. Finally, the in situ mapping of thin film growth rates across the ALD reactor was demonstrated in a popular commercial tool operating in both continuous and quasi-static ALD modes. PMID:23020393

  14. Design and validation of the mounting structure for BETTII balloon-based telescope with thin-walled optics

    NASA Astrophysics Data System (ADS)

    Furst, Stephen; Dow, Tom; Garrard, Ken; Sohn, Alex; Fixsen, Dale; Rinehart, Stephen; Mentzell, Eric; Veach, Todd; Rizzo, Maxime; Dhabal, Arnab

    2016-04-01

    The NASA Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) system is designed to study the infrared emissions from star formation and active galactic nuclei through a double-Fourier Michelson interferometer located on a balloon at an altitude of 37 km. The BETTII external optics include a pair of identical beam-reducing, four-mirror telescopes, each with a 522-mm aperture, nonrotationally symmetric primary mirror. These telescopes were designed and assembled at the North Carolina State University Precision Engineering Consortium and are composed entirely of thin-walled aluminum components. The mounting structure is designed to be light weight and stiff to reduce thermal equilibration time in the rarified air at the edge of space and to maintain robust alignment of the optical elements. The mounts also prevent deformation of the large optical elements via custom-built kinematic Kelvin couplings and fixed-load clamps; the maximum form error of the optical surfaces are 300 nm RMS. This work details the design of the thin mirrors and mounting structure as well as validation of the mount assembly process, mount stiffness, and the kinematic couplings.

  15. A More Realistic Lateral Load Pattern for Design of Reinforced Concrete Buildings with Moment Frames and Shear Walls

    SciTech Connect

    Hosseini, Mahmood

    2008-07-08

    In this research it has been tried to find a more realistic distribution pattern for the seismic load in reinforced concrete (R/C) buildings, having moment frames with shear walls as their lateral resisting system, by using Nonlinear Time History Analyses (NLTHA). Having shear wall as lateral load bearing system decreases the effect of infill walls in the seismic behavior of the building, and therefore the case of buildings with shear walls has been considered for this study as the first stage of the studies on lateral load patterns for R/C buildings. For this purpose, by assuming three different numbers of bays in each direction and also three different numbers of stories for the buildings, several R/C buildings, have been studied. At first, the buildings have been designed by the Iranian National Code for R/C Buildings. Then they have been analyzed by a NLTHA software using the accelerograms of some well-known earthquakes. The used accelerograms have been also scaled to various levels of peak ground acceleration (PGA) such as 0.35 g, 0.50 g, and 0.70 g, to find out the effect of PGA in the seismic response. Numerical results have shown that firstly the values of natural period of the building and their shear force values, calculated by the code, are not appropriate in all cases. Secondly, it has been found out that the real lateral load pattern is quite different with the one suggested by the seismic code. Based on the NLTHA results a new lateral load pattern has been suggested for this kind of buildings, in the form of some story-dependent modification factors applied to the existing code formula. The effects of building's natural period, as well as its number of stories, are taken into account explicitly in the proposed new load pattern. The proposed load pattern has been employed to redesign the buildings and again by NLTHA the real lateral load distribution in each case has been obtained which has shown very good agreement with the proposed pattern.

  16. Localizing gravity on exotic thick 3-branes

    SciTech Connect

    Castillo-Felisola, Oscar; Melfo, Alejandra; Pantoja, Nelson; Ramirez, Alba

    2004-11-15

    We consider localization of gravity on thick branes with a nontrivial structure. Double walls that generalize the thick Randall-Sundrum solution, and asymmetric walls that arise from a Z{sub 2} symmetric scalar potential, are considered. We present a new asymmetric solution: a thick brane interpolating between two AdS{sub 5} spacetimes with different cosmological constants, which can be derived from a 'fake supergravity' superpotential, and show that it is possible to confine gravity on such branes.

  17. Preliminary investigation on the requirements of the first wall and limiter of HL-2M prior to its detailed design

    NASA Astrophysics Data System (ADS)

    Cai, Laizhong; Li, Jiaxian; the HL-2M Team

    2015-02-01

    Some plasma facing components (PFCs) have to face extreme environments with high heat load as well as high particle flux during tokamak operations. Specifying the conditions of the PFCs of a tokamak during discharges is a critical issue prior to detailed design of a new device. Heat loads on different regions of PFCs are the most important parameters for PFCs and have to be provided as input into the engineering design. Particularly for the limiter, more investigations of heat loads are required since a number of accidents, including the one involving the JET limiter, have occurred due to underestimation of heat loads. In this paper, the factors affecting the heat loads of the first wall and the limiter of HL-2M are discussed. Several typical operation scenarios, including the first plasma, the start-up phase and flat-top phase of normal operations, and the key transient conditions, specifically disruptions and vertical displacement events, are analyzed for HL-2M, and the heat load specifications of different regions of PFCs are presented. Then the temperature rise and material erosion of PFCs are also evaluated. The results show that under the typical operation scenarios discussed in this paper, heat loads on the PFCs except the limiter are tolerable and temperature rise and material erosion are acceptable too. As for the limiter, the results reveal that the plasma current has to be lower than 0.5 MA if the plasma is operated in a limiter configuration. The investigation also implies that it is feasible to implement the first plasma without the first wall of graphite for the first plasma discussed in this analysis. However, the values obtained in this paper are based on a few simplifications, and further simulations are required involving ripple loss, start-up evolution, and the influence of ELMs on PFCs during further investigations.

  18. Welded repairs of punctured thin-walled aluminum pressure vessels

    NASA Technical Reports Server (NTRS)

    Jones, D. J.

    1969-01-01

    Punctures in thin-walled aluminum pressure vessels are repaired by plugging the hole with an interference-fit disc and welding the unit. The repaired vessels withstood test pressures in excess of vessel ultimate design values for 2-, 4-, and 6-inch holes in 0.202-inch-thick aluminum alloy parent material.

  19. Novel 3D ultrasound image-based biomarkers based on a feature selection from a 2D standardized vessel wall thickness map: a tool for sensitive assessment of therapies for carotid atherosclerosis

    NASA Astrophysics Data System (ADS)

    Chiu, Bernard; Li, Bing; Chow, Tommy W. S.

    2013-09-01

    With the advent of new therapies and management strategies for carotid atherosclerosis, there is a parallel need for measurement tools or biomarkers to evaluate the efficacy of these new strategies. 3D ultrasound has been shown to provide reproducible measurements of plaque area/volume and vessel wall volume. However, since carotid atherosclerosis is a focal disease that predominantly occurs at bifurcations, biomarkers based on local plaque change may be more sensitive than global volumetric measurements in demonstrating efficacy of new therapies. The ultimate goal of this paper is to develop a biomarker that is based on the local distribution of vessel-wall-plus-plaque thickness change (VWT-Change) that has occurred during the course of a clinical study. To allow comparison between different treatment groups, the VWT-Change distribution of each subject must first be mapped to a standardized domain. In this study, we developed a technique to map the 3D VWT-Change distribution to a 2D standardized template. We then applied a feature selection technique to identify regions on the 2D standardized map on which subjects in different treatment groups exhibit greater difference in VWT-Change. The proposed algorithm was applied to analyse the VWT-Change of 20 subjects in a placebo-controlled study of the effect of atorvastatin (Lipitor). The average VWT-Change for each subject was computed (i) over all points in the 2D map and (ii) over feature points only. For the average computed over all points, 97 subjects per group would be required to detect an effect size of 25% that of atorvastatin in a six-month study. The sample size is reduced to 25 subjects if the average were computed over feature points only. The introduction of this sensitive quantification technique for carotid atherosclerosis progression/regression would allow many proof-of-principle studies to be performed before a more costly and longer study involving a larger population is held to confirm the treatment

  20. Application of the Ultrasonic Oil Film Thickness Measurement System in Bearing Chambers

    NASA Astrophysics Data System (ADS)

    Zhong, Chong; Hu, Jian-ping; Liu, Zhen-xia; Lu, Ya-guo; Hao, Yu-ya

    2014-06-01

    The oil film thickness in aero-engine bearing chamber influences the heat transfer capacity of the bearing chamber wall, so measuring oil film thickness accuspeedly is essential to the design and thermal analysis of lubricating oil system. In this paper, software and hardware of an ultrasonic measurement system based on pulse echo technique, which measures the oil film thickness in bearing chamber, are established. The hardware system mainly consists of signal acquisition card, probe, delay block and the corresponding cables. Functions as measurement parameter setup, real-time display of measured waveforms, post-processing and so on are included in the measurement software. Finally, the oil film thickness of the wall is measured with the measurement system developed. Signal quality of the dynamic measurement is analyzed. Comparison and analysis of different oil film thickness under different rotation rates are conducted.

  1. Geographic information system datasets of regolith-thickness data, regolith-thickness contours, raster-based regolith thickness, and aquifer-test and specific-capacity data for the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado

    USGS Publications Warehouse

    Arnold, L. Rick

    2010-01-01

    These datasets were compiled in support of U.S. Geological Survey Scientific-Investigations Report 2010-5082-Hydrogeology and Steady-State Numerical Simulation of Groundwater Flow in the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado. The datasets were developed by the U.S. Geological Survey in cooperation with the Lost Creek Ground Water Management District and the Colorado Geological Survey. The four datasets are described as follows and methods used to develop the datasets are further described in Scientific-Investigations Report 2010-5082: (1) ds507_regolith_data: This point dataset contains geologic information concerning regolith (unconsolidated sediment) thickness and top-of-bedrock altitude at selected well and test-hole locations in and near the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado. Data were compiled from published reports, consultant reports, and from lithologic logs of wells and test holes on file with the U.S. Geological Survey Colorado Water Science Center and the Colorado Division of Water Resources. (2) ds507_regthick_contours: This dataset consists of contours showing generalized lines of equal regolith thickness overlying bedrock in the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado. Regolith thickness was contoured manually on the basis of information provided in the dataset ds507_regolith_data. (3) ds507_regthick_grid: This dataset consists of raster-based generalized thickness of regolith overlying bedrock in the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado. Regolith thickness in this dataset was derived from contours presented in the dataset ds507_regthick_contours. (4) ds507_welltest_data: This point dataset contains estimates of aquifer transmissivity and hydraulic conductivity at selected well locations in the Lost Creek Designated Ground Water Basin, Weld, Adams, and

  2. Design of a Laboratory Hall Thruster with Magnetically Shielded Channel Walls, Phase I: Numerical Simulations

    NASA Technical Reports Server (NTRS)

    Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.

    2011-01-01

    In a proof-of-principle effort to demonstrate the feasibility of magnetically shielded (MS) Hall thrusters, an existing laboratory thruster has been modified with the guidance of physics-based numerical simulation. When operated at a discharge power of 6-kilowatts the modified thruster has been designed to reduce the total energy and flux of ions to the channel insulators by greater than 1 and greater than 3 orders of magnitude, respectively. The erosion rates in this MS thruster configuration are predicted to be at least 2-4 orders of magnitude lower than those in the baseline (BL) configuration. At such rates no detectable erosion is expected to occur.

  3. A rational design for the separation of metallic and semiconducting single-walled carbon nanotubes using a magnetic field

    NASA Astrophysics Data System (ADS)

    Luo, Chengzhi; Wan, Da; Jia, Junji; Li, Delong; Pan, Chunxu; Liao, Lei

    2016-06-01

    The separation of metallic (m-) and semiconducting (s-) single-walled carbon nanotubes (SWNTs) without causing contamination and damage is a major challenge for SWNT-based devices. As a facile and nondestructive tool, the use of a magnetic field could be an ideal strategy to separate m-/s-SWNTs, based on the difference of magnetic susceptibilities. Here, we designed a novel magnetic field-assisted floating catalyst chemical vapor deposition system to separate m-/s-SWNTs. Briefly, m-SWNTs are attracted toward the magnetic pole, leaving s-SWNTs on the substrate. By using this strategy, s-SWNTs with a purity of 99% could be obtained, which is enough to construct high-performance transistors with a mobility of 230 cm2 V-1 s-1 and an on/off ratio of 106. We also established a model to quantitatively calculate the percentage of m-SWNTs on the substrate and this model shows a good match with the experimental data. Furthermore, our rational design also provides a new avenue for the growth of SWNTs with specific chirality and manipulated arrangement due to the difference of magnetic susceptibilities between different diameters, chiralities, and types.The separation of metallic (m-) and semiconducting (s-) single-walled carbon nanotubes (SWNTs) without causing contamination and damage is a major challenge for SWNT-based devices. As a facile and nondestructive tool, the use of a magnetic field could be an ideal strategy to separate m-/s-SWNTs, based on the difference of magnetic susceptibilities. Here, we designed a novel magnetic field-assisted floating catalyst chemical vapor deposition system to separate m-/s-SWNTs. Briefly, m-SWNTs are attracted toward the magnetic pole, leaving s-SWNTs on the substrate. By using this strategy, s-SWNTs with a purity of 99% could be obtained, which is enough to construct high-performance transistors with a mobility of 230 cm2 V-1 s-1 and an on/off ratio of 106. We also established a model to quantitatively calculate the percentage of m

  4. Precise measurement of micro bubble resonator thickness by internal aerostatic pressure sensing.

    PubMed

    Lu, Qijing; Liao, Jie; Liu, Sheng; Wu, Xiang; Liu, Liying; Xu, Lei

    2016-09-01

    We develop a new, simple and non-destructive method to precisely measure the thickness of thin wall micro bubble resonators (MBRs) by using internal aerostatic pressure sensing. Measurement error of 1% at a bubble wall thickness of 2 μm is achieved. This method is applicable to both thin wall and thick wall MBR with high measurement accuracy. PMID:27607689

  5. Thick Toenails

    MedlinePlus

    ... be seen in individuals with nail fungus (onychomycosis), psoriasis, and hypothyroidism. Those who have problems with the thickness of their toenails should consult a foot and ankle surgeon for proper diagnosis and treatment. and or or and or or, browse by ...

  6. Moisture Research - Optimizing Wall Assemblies

    SciTech Connect

    Arena, Lois; Mantha, Pallavi

    2013-05-01

    In this project, the Consortium for Advanced Residential Buildings (CARB) team evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls. Wall assemblies evaluated included code minimum walls using spray foam insulation and fiberglass batts, high R-value walls at least 12 in. thick (R-40 and R-60 assemblies), and brick walls with interior insulation.

  7. Design and evaluation of an in-situ ground water treatment wall composed of zero-valent iron

    SciTech Connect

    Gallinatti, J.D.; Warner, S.D.; Yamane, C.L.; Szerdy, F.S.; Hankins, D.A.; Major, D.W.

    1995-09-01

    An in-situ permeable treatment wall using zero-valent iron for the remediation of ground water affected by chlorinated volatile organic compounds (VOCs) was recently constructed in Sunnyvale, California. Because this site was the first full-scale application of this technology as a final remedy of VOC-affected ground water, it provides a framework for assessing the factors that must be considered when moving from laboratory studies of this treatment technology to design and construction of a full-scale treatment system. Experience from this case study is valuable for both practical design considerations and as incentives for future research. The patented treatment process, licensed by Environmental Technologies Inc., utilizes granular zero-valent iron as a porous medium to enhance the degradation of VOCs dissolved in ground water. The dissolved VOCs, such as 1,1,1-trichloroethylene (TCE), that pass through the granular iron matrix are transformed through the oxidation of the iron and reductive dechlorination of the organic compound to a final end product consisting chiefly of chloride and ethylene. The degradation process appears to be abiotic and half-lifes of the transformations are several orders of magnitude faster in the presence of zero-valent granular iron than observed in the ambient environment.

  8. Optimization of thiamethoxam adsorption parameters using multi-walled carbon nanotubes by means of fractional factorial design.

    PubMed

    Panić, Sanja; Rakić, Dušan; Guzsvány, Valéria; Kiss, Erne; Boskovic, Goran; Kónya, Zoltán; Kukovecz, Ákos

    2015-12-01

    The aim of this work was to evaluate significant factors affecting the thiamethoxam adsorption efficiency using oxidized multi-walled carbon nanotubes (MWCNTs) as adsorbents. Five factors (initial solution concentration of thiamethoxam in water, temperature, solution pH, MWCNTs weight and contact time) were investigated using 2V(5-1) fractional factorial design. The obtained linear model was statistically tested using analysis of variance (ANOVA) and the analysis of residuals was used to investigate the model validity. It was observed that the factors and their second-order interactions affecting the thiamethoxam removal can be divided into three groups: very important, moderately important and insignificant ones. The initial solution concentration was found to be the most influencing parameter on thiamethoxam adsorption from water. Optimization of the factors levels was carried out by minimizing those parameters which are usually critical in real life: the temperature (energy), contact time (money) and weight of MWCNTs (potential health hazard), in order to maximize the adsorbed amount of the pollutant. The results of maximal adsorbed thiamethoxam amount in both real and optimized experiments indicate that among minimized parameters the adsorption time is one that makes the largest difference. The results of this study indicate that fractional factorial design is very useful tool for screening the higher number of parameters and reducing the number of adsorption experiments. PMID:26151482

  9. A rational design for the separation of metallic and semiconducting single-walled carbon nanotubes using a magnetic field.

    PubMed

    Luo, Chengzhi; Wan, Da; Jia, Junji; Li, Delong; Pan, Chunxu; Liao, Lei

    2016-07-14

    The separation of metallic (m-) and semiconducting (s-) single-walled carbon nanotubes (SWNTs) without causing contamination and damage is a major challenge for SWNT-based devices. As a facile and nondestructive tool, the use of a magnetic field could be an ideal strategy to separate m-/s-SWNTs, based on the difference of magnetic susceptibilities. Here, we designed a novel magnetic field-assisted floating catalyst chemical vapor deposition system to separate m-/s-SWNTs. Briefly, m-SWNTs are attracted toward the magnetic pole, leaving s-SWNTs on the substrate. By using this strategy, s-SWNTs with a purity of 99% could be obtained, which is enough to construct high-performance transistors with a mobility of 230 cm(2) V(-1) s(-1) and an on/off ratio of 10(6). We also established a model to quantitatively calculate the percentage of m-SWNTs on the substrate and this model shows a good match with the experimental data. Furthermore, our rational design also provides a new avenue for the growth of SWNTs with specific chirality and manipulated arrangement due to the difference of magnetic susceptibilities between different diameters, chiralities, and types. PMID:27315328

  10. Design considerations for characterizing psychiatric trajectories across the lifespan: application to effects of APOE-ε4 on cerebral cortical thickness in Alzheimer's disease.

    PubMed

    Thompson, Wesley K; Hallmayer, Joachim; O'Hara, Ruth

    2011-09-01

    Characterization of developmental trajectories across the lifespan is integral to understanding the prodromal course of many neuropsychiatric illnesses and the significant risk factors for disease onset or unfavorable outcomes. However, the standard experimental designs used in psychiatric research are not ideal for this purpose. The authors review the limitations of the most commonly employed designs in studies that make developmental or lifespan inferences in psychiatry: cross-sectional, single-cohort longitudinal, and unstructured multicohort longitudinal designs. Cross-sectional studies completely confound within- and between-subject sources of variation and hence rely on the presence of parallel trajectories and negligible sampling and age cohort differences for making valid developmental inferences. Delineating trajectories of within-individual change over substantial periods of time requires data covering long age spans that often cannot be covered using single-cohort longitudinal designs. Unstructured multicohort longitudinal designs are a commonly used alternative that can cover a longer age span in a shorter interval than necessary for a single-cohort design. However, the impact of cohort and sampling effects is often minimized or ignored in unstructured multicohort longitudinal designs. The authors propose that structured multicohort longitudinal designs are a particularly viable and underutilized class of designs in psychiatry that represents a significant improvement over cross-sectional designs and unstructured multicohort longitudinal designs for making developmental inferences while being more practical to implement than single-cohort longitudinal designs. As an example of this approach, the authors analyze changes in entorhinal cortex thickness in Alzheimer's disease in relation to APOE-ε4 genotype. PMID:21724665

  11. Rational Design of QCM-D Virtual Sensor Arrays Based on Film Thickness, Viscoelasticity, and Harmonics for Vapor Discrimination.

    PubMed

    Speller, Nicholas C; Siraj, Noureen; Regmi, Bishnu P; Marzoughi, Hassan; Neal, Courtney; Warner, Isiah M

    2015-01-01

    Herein, we demonstrate an alternative strategy for creating QCM-based sensor arrays by use of a single sensor to provide multiple responses per analyte. The sensor, which simulates a virtual sensor array (VSA), was developed by depositing a thin film of ionic liquid, either 1-octyl-3-methylimidazolium bromide ([OMIm][Br]) or 1-octyl-3-methylimidazolium thiocyanate ([OMIm][SCN]), onto the surface of a QCM-D transducer. The sensor was exposed to 18 different organic vapors (alcohols, hydrocarbons, chlorohydrocarbons, nitriles) belonging to the same or different homologous series. The resulting frequency shifts (Δf) were measured at multiple harmonics and evaluated using principal component analysis (PCA) and discriminant analysis (DA) which revealed that analytes can be classified with extremely high accuracy. In almost all cases, the accuracy for identification of a member of the same class, that is, intraclass discrimination, was 100% as determined by use of quadratic discriminant analysis (QDA). Impressively, some VSAs allowed classification of all 18 analytes tested with nearly 100% accuracy. Such results underscore the importance of utilizing lesser exploited properties that influence signal transduction. Overall, these results demonstrate excellent potential of the virtual sensor array strategy for detection and discrimination of vapor phase analytes utilizing the QCM. To the best of our knowledge, this is the first report on QCM VSAs, as well as an experimental sensor array, that is based primarily on viscoelasticity, film thickness, and harmonics. PMID:25913394

  12. Design of new block copolymer systems to achieve thick films with defect-free structures for applications of DSA into lithographic large nodes

    NASA Astrophysics Data System (ADS)

    Chevalier, X.; Coupillaud, P.; Lombard, G.; Nicolet, C.; Beausoleil, J.; Fleury, G.; Zelsmann, M.; Bezard, P.; Cunge, G.; Berron, J.; Sakavuyi, K.; Gharbi, A.; Tiron, R.; Hadziioannou, G.; Navarro, C.; Cayrefourcq, I.

    2016-03-01

    Properties of new block copolymers systems, specifically designed to reach large periods for the features, are compared to the ones exhibited by classical PS-b-PMMA materials of same dimensions. Conducted studies, like free-surface defects analysis, mild-plasma tomography experiments, graphoepitaxy-guided structures, etch-transfer… indicate much better performances, in terms of achievable film-thicknesses with perpendicular features, defects levels, and dimensional uniformities, for the new system than for the classical PS-b-PMMA. These results clearly highlight unique and original solutions toward an early introduction of DSA technology into large lithographic nodes.

  13. A performance-based method for calculating the design thickness of compacted clay liners exposed to high strength leachate under simulated landfill conditions.

    PubMed

    Safari, Edwin; Jalili Ghazizade, Mahdi; Abdoli, Mohammad Ali

    2012-09-01

    Compacted clay liners (CCLs) when feasible, are preferred to composite geosynthetic liners. The thickness of CCLs is typically prescribed by each country's environmental protection regulations. However, considering the fact that construction of CCLs represents a significant portion of overall landfill construction costs; a performance based design of liner thickness would be preferable to 'one size fits all' prescriptive standards. In this study researchers analyzed the hydraulic behaviour of a compacted clayey soil in three laboratory pilot scale columns exposed to high strength leachate under simulated landfill conditions. The temperature of the simulated CCL at the surface was maintained at 40 ± 2 °C and a vertical pressure of 250 kPa was applied to the soil through a gravel layer on top of the 50 cm thick CCL where high strength fresh leachate was circulated at heads of 15 and 30 cm simulating the flow over the CCL. Inverse modelling using HYDRUS-1D indicated that the hydraulic conductivity after 180 days was decreased about three orders of magnitude in comparison with the values measured prior to the experiment. A number of scenarios of different leachate heads and persistence time were considered and saturation depth of the CCL was predicted through modelling. Under a typical leachate head of 30 cm, the saturation depth was predicted to be less than 60 cm for a persistence time of 3 years. This approach can be generalized to estimate an effective thickness of a CCL instead of using prescribed values, which may be conservatively overdesigned and thus unduly costly. PMID:22617473

  14. Corrections to the thin wall approximation in general relativity

    NASA Technical Reports Server (NTRS)

    Garfinkle, David; Gregory, Ruth

    1989-01-01

    The question is considered whether the thin wall formalism of Israel applies to the gravitating domain walls of a lambda phi(exp 4) theory. The coupled Einstein-scalar equations that describe the thick gravitating wall are expanded in powers of the thickness of the wall. The solutions of the zeroth order equations reproduce the results of the usual Israel thin wall approximation for domain walls. The solutions of the first order equations provide corrections to the expressions for the stress-energy of the wall and to the Israel thin wall equations. The modified thin wall equations are then used to treat the motion of spherical and planar domain walls.

  15. Dose reduction of scattered photons from concrete walls lined with lead: Implications for improvement in design of megavoltage radiation therapy facility mazes

    SciTech Connect

    Al-Affan, I. A. M. Hugtenburg, R. P.; Piliero, M.; Bari, D. S.; Al-Saleh, W. M.; Evans, S.; Al-Hasan, M.; Al-Zughul, B.; Al-Kharouf, S.; Ghaith, A.

    2015-02-15

    Purpose: This study explores the possibility of using lead to cover part of the radiation therapy facility maze walls in order to absorb low energy photons and reduce the total dose at the maze entrance of radiation therapy rooms. Methods: Experiments and Monte Carlo simulations were utilized to establish the possibility of using high-Z materials to cover the concrete walls of the maze in order to reduce the dose of the scattered photons at the maze entrance. The dose of the backscattered photons from a concrete wall was measured for various scattering angles. The dose was also calculated by the FLUKA and EGSnrc Monte Carlo codes. The FLUKA code was also used to simulate an existing radiotherapy room to study the effect of multiple scattering when adding lead to cover the concrete walls of the maze. Monoenergetic photons were used to represent the main components of the x ray spectrum up to 10 MV. Results: It was observed that when the concrete wall was covered with just 2 mm of lead, the measured dose rate at all backscattering angles was reduced by 20% for photons of energy comparable to Co-60 emissions and 70% for Cs-137 emissions. The simulations with FLUKA and EGS showed that the reduction in the dose was potentially even higher when lead was added. One explanation for the reduction is the increased absorption of backscattered photons due to the photoelectric interaction in lead. The results also showed that adding 2 mm lead to the concrete walls and floor of the maze reduced the dose at the maze entrance by up to 90%. Conclusions: This novel proposal of covering part or the entire maze walls with a few millimeters of lead would have a direct implication for the design of radiation therapy facilities and would assist in upgrading the design of some mazes, especially those in facilities with limited space where the maze length cannot be extended to sufficiently reduce the dose.

  16. The design and operational development of self-streamlining 2-dimensional flexible walled test sections. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Wolf, S. W. D.

    1984-01-01

    Self streamlining two dimensional flexible walled test sections eliminate the uncertainties found in data from conventional test sections particularly at transonic speeds. The test section sidewalls are rigid, while the floor and ceiling are flexible and are positioned to streamline shapes by a system of jacks, without reference to the model. The walls are therefore self streamlining. Data are taken from the model when the walls are good streamlines such that the inevitable residual wall induced interference is acceptably small and correctable. Successful two dimensional validation testing at low speeds has led to the development of a new transonic flexible walled test section. Tunnel setting times are minimized by the development of a rapid wall setting strategy coupled with on line computer control of wall shapes using motorized jacks. Two dimensional validation testing using symmetric and cambered aerofoils in the Mach number range up to about 0.85 where the walls are just supercritical, shows good agreement with reference data using small height-chord ratios between 1.5 and unity.

  17. Depth to Water, Saturated Thickness, and Other Geospatial Datasets Used in the Design and Installation of a Groundwater Monitoring-Well Network in the High Plains Aquifer, Colorado

    USGS Publications Warehouse

    Flynn, Jennifer L.; Arnold, L. Rick; Paschke, Suzanne S.

    2009-01-01

    These datasets were compiled in support of U.S. Geological Survey Data Series 456, Design and Installation of a Groundwater Monitoring-Well Network in the High Plains Aquifer, Colorado. These datasets were developed as part of a cooperative project between the U.S. Geological Survey and the Colorado Department of Agriculture. The purpose of the project was to design a 30-well network and install 20 of the 30 wells to characterize water quality in the High Plains aquifer in areas of irrigated agriculture in Colorado. The five datasets are described as follows and are further described in Data Series 456: (1) ds472_dtw: This dataset represents the depth to groundwater in the High Plains Aquifer in Colorado in 2000. This grid was used to determine areas where the depth to water was less than 200 feet below land surface. (2) Ds472_sat: This dataset represents the saturated thickness of the High Plains aquifer within Colorado in 2000. This grid was used to determine areas where the saturated thickness was greater than 50 feet. (3) Ds472_equalareas: This dataset includes 30 equal-area polygons overlying the High Plains Aquifer in Colorado having a depth to water less than 200 feet, a saturated thickness greater than 50 feet, and underlying irrigated agricultural lands. (4) Ds472_randomsites: This dataset includes 90 randomly-generated potential groundwater sampling sites. This dataset provides a first, second, and third choice placed within the 30 equal area polygons of dataset dsXX_equalareas. (5) Ds472_welldata: This dataset includes point locations and well completion data for the 20 wells installed as part of this project. The datasets that pertain to this report can be found on the U.S. Geological Survey's NSDI (National Spatial Data Infrastructure) Node, the links are provided on the sidebar.

  18. The thickness design of unintentionally doped GaN interlayer matched with background doping level for InGaN-based laser diodes

    NASA Astrophysics Data System (ADS)

    Chen, P.; Zhao, D. G.; Jiang, D. S.; Zhu, J. J.; Liu, Z. S.; Yang, J.; Li, X.; Le, L. C.; He, X. G.; Liu, W.; Li, X. J.; Liang, F.; Zhang, B. S.; Yang, H.; Zhang, Y. T.; Du, G. T.

    2016-03-01

    In order to reduce the internal optical loss of InGaN laser diodes, an unintentionally doped GaN (u-GaN) interlayer is inserted between InGaN/GaN multiple quantum well active region and Al0.2Ga0.8N electron blocking layer. The thickness design of u-GaN interlayer matching up with background doping level for improving laser performance is studied. It is found that a suitably chosen u-GaN interlayer can well modulate the optical absorption loss and optical confinement factor. However, if the value of background doping concentration of u-GaN interlayer is too large, the output light power may decrease. The analysis of energy band diagram of a LD structure with 100 nm u-GaN interlayer shows that the width of n-side depletion region decreases when the background concentration increases, and may become even too small to cover whole MQW, resulting in a serious decrease of the output light power. It means that a suitable interlayer thickness design matching with the background doping level of u-GaN interlayer is significant for InGaN-based laser diodes.

  19. Ultrasonic thickness measuring and imaging system and method

    DOEpatents

    Bylenok, Paul J.; Patmos, William M.; Wagner, Thomas A.; Martin, Francis H.

    1992-08-04

    An ultrasonic thickness measuring and imaging system uses an ultrasonic fsed beam probe for measuring thickness of an object, such as a wall of a tube, a computer for controlling movement of the probe in a scanning pattern within the tube and processing an analog signal produced by the probe which is proportional to the tube wall thickness in the scanning pattern, and a line scan recorder for producing a record of the tube wall thicknesses measured by the probe in the scanning pattern. The probe is moved in the scanning pattern to sequentially scan circumferentially the interior tube wall at spaced apart adjacent axial locations. The computer processes the analog signal by converting it to a digital signal and then quantifies the digital signal into a multiplicity of thickness points with each falling in one of a plurality of thickness ranges corresponding to one of a plurality of shades of grey. From the multiplicity of quantified thickness points, a line scan recorder connected to the computer generates a pictorial map of tube wall thicknesses with each quantified thickness point thus being obtained from a minute area, e.g. 0.010 inch by 0.010 inch, of tube wall and representing one pixel of the pictorial map. In the pictorial map of tube wall thicknesses, the pixels represent different wall thicknesses having different shades of grey.

  20. Ultrasonic thickness measuring and imaging system and method

    DOEpatents

    Bylenok, Paul J.; Patmos, William M.; Wagner, Thomas A.; Martin, Francis H.

    1992-01-01

    An ultrasonic thickness measuring and imaging system uses an ultrasonic fsed beam probe for measuring thickness of an object, such as a wall of a tube, a computer for controlling movement of the probe in a scanning pattern within the tube and processing an analog signal produced by the probe which is proportional to the tube wall thickness in the scanning pattern, and a line scan recorder for producing a record of the tube wall thicknesses measured by the probe in the scanning pattern. The probe is moved in the scanning pattern to sequentially scan circumferentially the interior tube wall at spaced apart adjacent axial locations. The computer processes the analog signal by converting it to a digital signal and then quantifies the digital signal into a multiplicity of thickness points with each falling in one of a plurality of thickness ranges corresponding to one of a plurality of shades of grey. From the multiplicity of quantified thickness points, a line scan recorder connected to the computer generates a pictorial map of tube wall thicknesses with each quantified thickness point thus being obtained from a minute area, e.g. 0.010 inch by 0.010 inch, of tube wall and representing one pixel of the pictorial map. In the pictorial map of tube wall thicknesses, the pixels represent different wall thicknesses having different shades of grey.

  1. Low-speed aerodynamic characteristics of a 16-percent-thick variable-geometry airfoil designed for general aviation applications

    NASA Technical Reports Server (NTRS)

    Barnwell, R. W.; Noonan, K. W.; Mcghee, R. J.

    1978-01-01

    Tests were conducted in the Langley low-turbulence pressure tunnel to determine the aerodynamic characteristics of climb, cruise, and landing configurations. These tests were conducted over a Mach number range from 0.10 to 0.35, a chord Reynolds number range from 2.0 x 1 million to 20.0 x 1 million, and an angle-of-attack range from -8 deg to 20 deg. Results show that the maximum section lift coefficients increased in the Reynolds number range from 2.0 x 1 million to 9.0 x 1 million and reached values of approximately 2.1, 1.8, and 1.5 for the landing, climb, and cruise configurations, respectively. Stall characteristics, although of the trailing-edge type, were abrupt. The section lift-drag ratio of the climb configuration with fixed transition near the leading edge was about 78 at a lift coefficient of 0.9, a Mach number of 0.15, and a Reynolds number of 4.0 x 1 million. Design lift coefficients of 0.9 and 0.4 for the climb and cruise configurations were obtained at the same angle of attack, about 6 deg, as intended. Good agreement was obtained between experimental results and the predictions of a viscous, attached-flow theoretical method.

  2. Spatial variability of organic layer thickness and carbon stocks in mature boreal forest stands--implications and suggestions for sampling designs.

    PubMed

    Kristensen, Terje; Ohlson, Mikael; Bolstad, Paul; Nagy, Zoltan

    2015-08-01

    Accurate field measurements from inventories across fine spatial scales are critical to improve sampling designs and to increase the precision of forest C cycling modeling. By studying soils undisturbed from active forest management, this paper gives a unique insight in the naturally occurring variability of organic layer C and provides valuable references against which subsequent and future sampling schemes can be evaluated. We found that the organic layer C stocks displayed great short-range variability with spatial autocorrelation distances ranging from 0.86 up to 2.85 m. When spatial autocorrelations are known, we show that a minimum of 20 inventory samples separated by ∼5 m is needed to determine the organic layer C stock with a precision of ±0.5 kg C m(-2). Our data also demonstrates a strong relationship between the organic layer C stock and horizon thickness (R (2) ranging from 0.58 to 0.82). This relationship suggests that relatively inexpensive measurements of horizon thickness can supplement soil C sampling, by reducing the number of soil samples collected, or to enhance the spatial resolution of organic layer C mapping. PMID:26205281

  3. Wall Finishes; Carpentry: 901895.

    ERIC Educational Resources Information Center

    Dade County Public Schools, Miami, FL.

    The course outline is designed to provide instruction in selecting, preparing, and installing wall finishing materials. Prerequisites for the course include mastery of building construction plans, foundations and walls, and basic mathematics. Intended for use in grades 11 and 12, the course contains five blocks of study totaling 135 hours of…

  4. [Chest wall reconstruction after resection of malignant chest wall tumors].

    PubMed

    Ayabe, H; Oka, T; Akamine, S; Takahashi, T; Nagayasu, T

    1998-05-01

    Full-thickness chest wall resection is performed for complete removal of primary and secondary malignant chest wall tumors. Large defects of the chest wall after resection must be repaired to maintain adequate ventilation, to protect important intrathoracic structures, and to preserve cosmetic integrity. Various materials have been utilized over the years to replace the rigid chest wall. At present, Marlex mesh and a composite of Marlex mesh and methylmethacrylate are frequently used to reconstruct rigid chest wall defects. On the other hand, to replace the soft part of the chest wall and cover the rigid materials, pedicled muscle flaps, myocutaneous flaps, or omentum are used. Major pedicled flaps include the pectoralis major, rectus abdominis and latissimus dorsi muscular, and musculocutaneous flaps. Techniques are now available to repair any chest wall site, and to restore chest continuity in patients whose tumors are curatively resected. PMID:9656244

  5. Cooling wall

    SciTech Connect

    Nosenko, V.I.

    1995-07-01

    Protecting the shells of blast furnaces is being resolved by installing cast iron cooling plates. The cooling plates become non-operational in three to five years. The problem is that defects occur in manufacturing the cooling plates. With increased volume and intensity of work placed on blast furnaces, heat on the cast iron cooling plates reduces their reliability that limits the interim repair period of blast furnaces. Scientists and engineers from the Ukraine studied this problem for several years, developing a new method of cooling the blast furnace shaft called the cooling wall. Traditional cast iron plates were replaced by a screen of steel tubes, with the area between the tubes filled with fireproof concrete. Before placing the newly developed furnace shaft into operation, considerable work was completed such as theoretical calculations, design, research of temperature fields and tension. Continual testing over many years confirms the value of this research in operating blast furnaces. The cooling wall works with water cooling as well as vapor cooling and is operating in 14 blast furnaces in the Ukraine and two in Russia, and has operated for as long as 14 years.

  6. NOVA 201 ultrasonic thickness gage (NOVA Gage)

    NASA Technical Reports Server (NTRS)

    Garecht, Diane

    1990-01-01

    The measurement integrity of the NOVA 201 digital ultrasonic thickness gage (NOVA gage) was demonstrated by comparing the NOVA gage measurements to the thickness gage measurements, and determining the bias and uncertainty of the NOVA gage when measuring redesigned solid rocket motor (RSRM) hardware per engineering test plans (ETP). The NOVA gage was tested by three different operators on steel and aluminum RSRM hardware for wall thickness. The results show that the measurement bias is not consistent. The uncertainty of the bias is caused by the heterogeneous material properties of the RSRM components that influence the time of flight of ultrasonic waves. The measurement uncertainty inherent to the design and operation of the NOVA gage is less in comparison to the uncertainty of the bias. The total measurement uncertainty cannot be substantially reduced by taking more than one measurement. There is no correlation between bias and the surface finish range of this test unless 3-in-One oil is used as a couplant, in which case there appears to be a slight trend. There is no correlation between uncertainty and the surface finish range. The measurement uncertainty of the NOVA gage can be reduced using 3-in-One oil as a couplant.

  7. Study of imploding liner-electrode wall interaction

    SciTech Connect

    Chernyshev, V.K.; Zharinov, Y.I.; Kudolkin, I.D.; Ruzin, V.N.; Ionov, A.I.

    1994-12-01

    The report gives the results of the experiments on aluminum liner acceleration and their interaction with electrode walls. The liners having the radius of 30 mm, wall thickness of 1mm and 0.7 mm and a length of 30 mm are accelerated by a magnetic field, created by explosive magnetic generator (EMC). A helical generator 100 mm in diameter and 700 mm in length was used to create a magnetic field. During the process of compression a liner shape was recorded using X-ray facility. The report gives experimental set-up, electrical and design data of experimental units and diagnostic equipment data, also raw experimental data, analysis data and description of an analysis method. Based on the experiments the authors chose the method to bring a liner into a contact with electrode walls, which permits continuous contact of a liner with electrode wall is in the process of motion.

  8. Development on thin wall tubes of dispersion type

    NASA Astrophysics Data System (ADS)

    Zhang, Shien; Wang, Xiyou; Li, Jianshan; Zhang, Rongsheng; Xue, Zhenshu

    A method using powder metallurgy and metallic extrusion to manufacture three kinds of magnesium based thin wall tubes of dispersion type is presented. In each case, the composition of dispersed gold, boron and hafnium in magnesium matrix is 0.5 wt%, 1 wt%, 2 wt%, 4 wt% and 8 wt%, respectively. The diameter of the tubes are 20 mm with wall thickness of 1 mm. The process of mixing, compacting, lubricating, heat-extrusion, checking and die designing are described in detail. Measures for controlling tube tolerance and even distribution of dispersion phase, and improving the surface quality are suggested.

  9. Design of a Laboratory Hall Thruster with Magnetically Shielded Channel Walls, Phase III: Comparison of Theory with Experiment

    NASA Technical Reports Server (NTRS)

    Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.; Goebel, Dan M.

    2012-01-01

    A proof-of-principle effort to demonstrate a technique by which erosion of the acceleration channel in Hall thrusters of the magnetic-layer type can be eliminated has been completed. The first principles of the technique, now known as "magnetic shielding," were derived based on the findings of numerical simulations in 2-D axisymmetric geometry. The simulations, in turn, guided the modification of an existing 6-kW laboratory Hall thruster. This magnetically shielded (MS) thruster was then built and tested. Because neither theory nor experiment alone can validate fully the first principles of the technique, the objective of the 2-yr effort was twofold: (1) to demonstrate in the laboratory that the erosion rates can be reduced by >order of magnitude, and (2) to demonstrate that the near-wall plasma properties can be altered according to the theoretical predictions. This paper concludes the demonstration of magnetic shielding by reporting on a wide range of comparisons between results from numerical simulations and laboratory diagnostics. Collectively, we find that the comparisons validate the theory. Near the walls of the MS thruster, theory and experiment agree: (1) the plasma potential has been sustained at values near the discharge voltage, and (2) the electron temperature has been lowered by at least 2.5-3 times compared to the unshielded (US) thruster. Also, based on carbon deposition measurements, the erosion rates at the inner and outer walls of the MS thruster are found to be lower by at least 2300 and 1875 times, respectively. Erosion was so low along these walls that the rates were below the resolution of the profilometer. Using a sputtering yield model with an energy threshold of 25 V, the simulations predict a reduction of 600 at the MS inner wall. At the outer wall ion energies are computed to be below 25 V, for which case we set the erosion to zero in the simulations. When a 50-V threshold is used the computed ion energies are below the threshold at both

  10. Shockless airfoils with thicknesses of 20.6 and 20.7 percent chord analytically designed for a Mach number of 0.68 and a lift coefficient of 0.40

    NASA Technical Reports Server (NTRS)

    Allison, D. O.

    1976-01-01

    A 20.8 percent-thick airfoil shape was designed to have shockless inviscid flow at a Mach number of 0.68 and a lift coefficient of 0.40. In order to determine the actual airfoils which would yield this same shockless flow when viscous effects are included, boundary layer displacement thicknesses were subtracted from the inviscid shape for Reynolds numbers of 100 and 35 million. This process yielded airfoils with thicknesses of 20.7 and 20.6 percent, respectively. Subtraction of boundary layer displacement thicknesses for Reynolds numbers below 35 million yielded nonphysical airfoils, that is airfoils with negative thicknesses near tHe trailing edge. The pitching moment about the quarter-chord point at the design condition was -0.082 for the inviscid shape and, consequently, for both airfoils. Off-design calculations for the two airfoils were made using a computer program which provides for the interaction of the inviscid flow and boundary layer solutions. The pressure distributions of the airfoils were shockless for conditions from the design point to lower Mach numbers and lift coefficients. No boundary layer separation was predicted except in the last 3 percent chord on the upper surface.

  11. 4. STONE CABIN II CLOSEUP VIEW OF DOUBLE THICK FEATURE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. STONE CABIN II CLOSEUP VIEW OF DOUBLE THICK FEATURE OF THE ROCK WALL. WALL PHOTOGRAPHED IS THE NORTHERNMOST WALL TAKEN FROM THE INTERIOR OF STRUCTURE. CAMERA POINTED NORTHWEST. - Florida Mountain Mining Sites, Stone Cabin II, West slope Florida Mountain, East of Empire State Mine below summit, Silver City, Owyhee County, ID

  12. Development of a code for wall contour design in the transonic region of axisymmetric and square nozzles

    NASA Technical Reports Server (NTRS)

    Alcenius, Timothy; Schneider, Steven P.

    1994-01-01

    Nozzle design codes developed earlier under NAG1-1133 were modified and used in order to design a supersonic wind tunnel nozzle with square cross sections. As part of the design process, a computer code was written to implement the Hopkins and Hill perturbation solution for the flow in the transonic region of axisymmetric nozzles. This technique is used to design the bleed slot of quiet-flow nozzles. This new design code is documented in this report.

  13. Design of Advanced MnO/N-Gr 3D Walls through Polymer Cross-Linking for High-Performance Supercapacitor.

    PubMed

    Tran, Ngoc Quang; Kang, Bong Kyun; Tiruneh, Sintayehu Nibret; Yoon, Dae Ho

    2016-01-26

    Three-dimensional, vertically aligned MnO/nitrogen-doped graphene (3D MnO/N-Gr) walls were prepared through facile solution-phase synthesis followed by thermal treatment. Polyvinylpyrrolidone (PVP) was strategically added to generate cross-links to simultaneously form 3D wall structures and to incorporate nitrogen atoms into the graphene network. The unique wall features of the as-prepared 3D MnO/N-Gr hybirdes provide a large surface area (91.516 m(2) g(-1)) and allow for rapid diffusion of the ion electrolyte, resulting in a high specific capacitance of 378 F g(-1) at 0.25 A g(-1) and an excellent charge/discharge stability (93.7% capacity retention after 8000 cycles) in aqueous 1 m Na2 SO4 solution as electrolyte. Moreover, the symmetric supercapacitors that were rationally designed by using 3D MnO/N-Gr hybrids exhibit outstanding electrochemical performance in an organic electrolyte with an energy density of 90.6 Wh kg(-1) and a power density of 437.5 W kg(-1). PMID:26689298

  14. The role of pectic composition of cell walls in the determination of the new shape-functional design in galls of Baccharis reticularia (Asteraceae).

    PubMed

    Formiga, Anete Teixeira; de Oliveira, Denis Coelho; Ferreira, Bruno Garcia; Magalhães, Thiago Alves; de Castro, Ariane Chagas; Fernandes, G Wilson; Isaias, Rosy Mary Dos Santos

    2013-08-01

    The pectic composition of cell wall is altered during the processes of cell differentiation, plant growth, and development. These alterations may be time-dependent, and fluctuate in distinct regions of the same cell or tissue layer, due to the biotic stress caused by the activity of the gall inducer. Among the roles of the pectins in cell wall, elasticity, rigidity, porosity, and control of cell death may be crucial during gall development. Galls on Baccharis reticularia present species-specific patterns of development leading to related morphotypes where pectins were widely detected by Ruthenium red, and the pectic epitopes were labeled with specific monoclonal antibodies (LM1, LM2, LM5, LM6, JIM5, and JIM7) in distinct sites of the non-galled and the galled tissues. In the studied system B. reticularia, the epitopes for extensins were not labeled in the non-galled tissues, as well as in those of the rolling and kidney-shaped galls. The high methyl-esterified homogalacturonans (HGA) were labeled all over the tissues either of non-galled leaves or of the three gall morphotypes, while the intense labeling for arabinogalactans was obtained just in the rolling galls. The pectic composition of non-galled leaves denotes their maturity. The kidney-shaped gall was the most similar to the non-galled leaves. The pectic dynamics in the gall tissues was particularly altered in relation to low methyl-esterified HGA, which confers elasticity and expansion, as well as porosity and adhesion to cell walls, and are related to the homogenization and hypertrophy of gall cortex, and to translocation of solutes to the larval chamber. Herein, the importance of the pectic dynamics of cell walls to the new functional design established during gall development is discussed for the first time. The repetitive developmental patterns in galls are elegant models for studies on cell differentiation. PMID:23255001

  15. Cladding Attachment Over Thick Exterior Insulating Sheathing

    SciTech Connect

    Baker, P.; Eng, P.; Lepage, R.

    2014-01-01

    The addition of insulation to the exterior of buildings is an effective means of increasing the thermal resistance of both wood framed walls as well as mass masonry wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location (Straube and Smegal 2009, Pettit 2009, Joyce 2009, Ueno 2010). The research presented in this report is intended to help develop a better understanding of the system mechanics involved and the potential for environmental exposure induced movement between the furring strip and the framing. BSC sought to address the following research questions: 1. What are the relative roles of the mechanisms and the magnitudes of the force that influence the vertical displacement resistance of the system? 2. Can the capacity at a specified deflection be reliably calculated using mechanics based equations? 3. What are the impacts of environmental exposure on the vertical displacement of furring strips attached directly through insulation back to a wood structure?

  16. Cladding Attachment Over Thick Exterior Insulating Sheathing

    SciTech Connect

    Baker, P.; Eng, P.; Lepage, R.

    2014-01-01

    The addition of insulation to the exterior of buildings is an effective means of increasing the thermal resistance of both wood framed walls as well as mass masonry wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location (Straube and Smegal 2009, Pettit 2009, Joyce 2009, Ueno 2010). The research presented in this report is intended to help develop a better understanding of the system mechanics involved and the potential for environmental exposure induced movement between the furring strip and the framing. BSC sought to address the following research questions: 1.What are the relative roles of the mechanisms and the magnitudes of the force that influence the vertical displacement resistance of the system? 2.Can the capacity at a specified deflection be reliably calculated using mechanics based equations? 3.What are the impacts of environmental exposure on the vertical displacement of furring strips attached directly through insulation back to a wood structure?

  17. 49 CFR 192.125 - Design of copper pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Design of copper pipe. 192.125 Section 192.125... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Pipe Design § 192.125 Design of copper pipe. (a) Copper... hard drawn. (b) Copper pipe used in service lines must have wall thickness not less than that...

  18. 49 CFR 192.125 - Design of copper pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Design of copper pipe. 192.125 Section 192.125... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Pipe Design § 192.125 Design of copper pipe. (a) Copper... hard drawn. (b) Copper pipe used in service lines must have wall thickness not less than that...

  19. 49 CFR 192.125 - Design of copper pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Design of copper pipe. 192.125 Section 192.125... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Pipe Design § 192.125 Design of copper pipe. (a) Copper... hard drawn. (b) Copper pipe used in service lines must have wall thickness not less than that...

  20. 49 CFR 192.125 - Design of copper pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Design of copper pipe. 192.125 Section 192.125... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Pipe Design § 192.125 Design of copper pipe. (a) Copper... hard drawn. (b) Copper pipe used in service lines must have wall thickness not less than that...

  1. 49 CFR 192.125 - Design of copper pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Design of copper pipe. 192.125 Section 192.125... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Pipe Design § 192.125 Design of copper pipe. (a) Copper... hard drawn. (b) Copper pipe used in service lines must have wall thickness not less than that...

  2. Wonderful Walls

    ERIC Educational Resources Information Center

    Greenman, Jim

    2006-01-01

    In this article, the author emphasizes the importance of "working" walls in children's programs. Children's programs need "working" walls (and ceilings and floors) which can be put to use for communication, display, storage, and activity space. The furnishings also work, or don't work, for the program in another sense: in aggregate, they serve as…

  3. Wall Turbulence.

    ERIC Educational Resources Information Center

    Hanratty, Thomas J.

    1980-01-01

    This paper gives an account of research on the structure of turbulence close to a solid boundary. Included is a method to study the flow close to the wall of a pipe without interferring with it. (Author/JN)

  4. Kinetic investigation of the oxidation of naval excess hazardous materials in supercritical water for the design of a transpiration-wall reactor

    SciTech Connect

    Rice, S.F.; Hanush, R.G.; Hunter, T.B.

    1997-01-01

    Experiments were conducted in Sandia`s supercritical fluids reactor (SFR) to generate data for the design of a transpiration-wall supercritical water oxidation (SCWO) reactor. The reactor is intended for the disposal of hazardous material generated on naval vessels. The design parameters for the system require an accurate knowledge of destruction efficiency vs. time and temperature. Three candidate materials were selected for testing. The experiments consisted of oxidizing these materials in the SFR at isothermal conditions over the temperature range of 400-550C at 24.1 MPa. A small extrapolation of the results shows that these materials can be adequately destroyed (to 99.9% destruction removal efficiency, DRE, based on total organic carbon (TOC) in the effluent) in approximately 5 seconds at 600C. The results vary smoothly and predictably with temperature such that extrapolation to higher temperatures beyond the experimental capabilities of the SFR can be made with reasonable confidence. The preliminary design of the transpiration-wall reactor has a rapid heat-up section within the reactor vessel that requires the addition of a fuel capable of quickly reacting with oxygen at temperatures below 500C. Candidate alcohols and JP-5 jet fuel were evaluated in this context. Oxidation rates for the alcohols were examined using in situ Raman spectroscopy. In addition, the potential utility of supplying the oxidizer line with hydrogen peroxide as an additive to enhance rapid initiation of the feed at unusually low temperatures was investigated. Experiments were conducted in the Supercritical Constant Volume Reactor (SCVR) using hydrogen peroxide as the initial oxidizing species. The results show that this concept as a method of enhancing low temperature reactivity appears to fail because thermal decomposition of the hydrogen peroxide is more rapid than the fuel oxidation rate at low temperatures. 8 refs., 16 figs., 5 tabs.

  5. Reflections on Online Learning Designs and Cross-Institutional Research Collaborations: Revisiting "Classrooms without Walls" in Two Australian Universities

    ERIC Educational Resources Information Center

    Rossi, Dolene; van Rensburg, Henriette; Clark, Damien; Harreveld, R. E.; Beer, Colin; Danaher, P. A.

    2015-01-01

    The article on which this paper reflects ["Exploring a Cross-Institutional Research Collaboration and Innovation: Deploying Social Software and Web 2.0 Technologies to Investigate Online Learning Designs and Interactions in Two Australian Universities"] presented elements of a research project investigating learning interactions in…

  6. Detecting Cellulase Penetration Into Corn Stover Cell Walls by Immuno-Electron Microscopy

    SciTech Connect

    Donohoe, B. S.; Selig, M. J.; Viamajala, S.; Vinzant, T. B.; Adney, W. S.; Himmel, M. E.

    2009-06-15

    In general, pretreatments are designed to enhance the accessibility of cellulose to enzymes, allowing for more efficient conversion. In this study, we have detected the penetration of major cellulases present in a commercial enzyme preparation (Spezyme CP) into corn stem cell walls following mild-, moderate- and high-severity dilute sulfuric acid pretreatments. The Trichoderma reesei enzymes, Cel7A (CBH I) and Cel7B (EG I), as well as the cell wall matrix components xylan and lignin were visualized within digested corn stover cell walls by immuno transmission electron microscopy (TEM) using enzyme- and polymer-specific antibodies. Low severity dilute-acid pretreatment (20 min at 100 C) enabled <1% of the thickness of secondary cell walls to be penetrated by enzyme, moderate severity pretreatment at (20 min at 120 C) allowed the enzymes to penetrate {approx}20% of the cell wall, and the high severity (20 min pretreatment at 150 C) allowed 100% penetration of even the thickest cell walls. These data allow direct visualization of the dramatic effect dilute-acid pretreatment has on altering the condensed ultrastructure of biomass cell walls. Loosening of plant cell wall structure due to pretreatment and the subsequently improved access by cellulases has been hypothesized by the biomass conversion community for over two decades, and for the first time, this study provides direct visual evidence to verify this hypothesis. Further, the high-resolution enzyme penetration studies presented here provide insight into the mechanisms of cell wall deconstruction by cellulolytic enzymes.

  7. Design and characterization of thick InxGa1-xAs metamorphic buffer layers grown by hydride vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Schulte, K. L.; Zutter, B. T.; Wood, A. W.; Babcock, S. E.; Kuech, T. F.

    2014-03-01

    Thick InxGa1-xAs metamorphic buffer layers (MBLs) grown by hydride vapor phase epitaxy (HVPE) were studied. Relationships between MBL properties and growth parameters such as grading rate, cap layer thickness, final xInAs, and deposition temperature (TD) were explored. The MBLs were characterized by measurement of in-plane residual strain (ɛ¦¦), surface etch pit density (EPD), and surface roughness. Capping layer thickness had a strong effect on strain relaxation, with thickly capped samples exhibiting the lowest ɛ¦¦. EPD was higher in samples with thicker caps, reflecting their increased relaxation through dislocation generation. ɛ¦¦ and EPD were weakly affected by the grading rate, making capping layer thickness the primary structural parameter which controls these properties. MBLs graded in discrete steps had similar properties to MBLs with continuous grading. In samples with identical thickness and 10-step grading style, ɛ¦¦ increased almost linearly with final xInAs, while total relaxation stayed relatively constant. Relaxation as a function of xInAs could be described by an equilibrium model in which dislocation nucleation is impeded by the energy of the existing dislocation array. EPD was constant from xInAs = 0 to 0.24 then increased exponentially, which is related to the increased dislocation interaction and blocking seen at higher dislocation densities. RMS roughness increased with xInAs above a certain strain rate (0.15%/µm) samples grown below this level possessed large surface hillocks and high roughness values. The elimination of hillocks at higher values of xInAs is attributed to increased density of surface steps and is related to the out-of-plane component of the burgers vector of the dominant type of 60° dislocation. TD did not affect ɛ¦¦ for samples with a given xInAs. EPD tended to increase with TD, indicating dislocation glide likely is impeded at higher temperatures.

  8. Experimental, numerical, and analytical studies on the seismic response of steel-plate concrete (SC) composite shear walls

    NASA Astrophysics Data System (ADS)

    Epackachi, Siamak

    The seismic performance of rectangular steel-plate concrete (SC) composite shear walls is assessed for application to buildings and mission-critical infrastructure. The SC walls considered in this study were composed of two steel faceplates and infill concrete. The steel faceplates were connected together and to the infill concrete using tie rods and headed studs, respectively. The research focused on the in-plane behavior of flexure- and flexure-shear-critical SC walls. An experimental program was executed in the NEES laboratory at the University at Buffalo and was followed by numerical and analytical studies. In the experimental program, four large-size specimens were tested under displacement-controlled cyclic loading. The design variables considered in the testing program included wall thickness, reinforcement ratio, and slenderness ratio. The aspect ratio (height-to-length) of the four walls was 1.0. Each SC wall was installed on top of a re-usable foundation block. A bolted baseplate to RC foundation connection was used for all four walls. The walls were identified to be flexure- and flexure-shear critical. The progression of damage in the four walls was identical, namely, cracking and crushing of the infill concrete at the toes of the walls, outward buckling and yielding of the steel faceplates near the base of the wall, and tearing of the faceplates at their junctions with the baseplate. A robust finite element model was developed in LS-DYNA for nonlinear cyclic analysis of the flexure- and flexure-shear-critical SC walls. The DYNA model was validated using the results of the cyclic tests of the four SC walls. The validated and benchmarked models were then used to conduct a parametric study, which investigated the effects of wall aspect ratio, reinforcement ratio, wall thickness, and uniaxial concrete compressive strength on the in-plane response of SC walls. Simplified analytical models, suitable for preliminary analysis and design of SC walls, were

  9. Conducting Wall Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Goebel, Dan M.; Hofer, Richard R.; Mikellides, Ioannis G.; Katz, Ira; Polk, James E.; Dotson, Brandon

    2013-01-01

    A unique configuration of the magnetic field near the wall of Hall thrusters, called Magnetic Shielding, has recently demonstrated the ability to significantly reduce the erosion of the boron nitride (BN) walls and extend the life of Hall thrusters by orders of magnitude. The ability of magnetic shielding to minimize interactions between the plasma and the discharge chamber walls has for the first time enabled the replacement of insulating walls with conducting materials without loss in thruster performance. The boron nitride rings in the 6 kW H6 Hall thruster were replaced with graphite that self-biased to near the anode potential. The thruster efficiency remained over 60% (within two percent of the baseline BN configuration) with a small decrease in thrust and increase in Isp typical of magnetically shielded Hall thrusters. The graphite wall temperatures decreased significantly compared to both shielded and unshielded BN configurations, leading to the potential for higher power operation. Eliminating ceramic walls makes it simpler and less expensive to fabricate a thruster to survive launch loads, and the graphite discharge chamber radiates more efficiently which increases the power capability of the thruster compared to conventional Hall thruster designs.

  10. Clinically-Relevant Design Features of a Three-Dimensional Correct Molar Crown and Related Maximum Principal Stress. A Finite Element Model Study

    PubMed Central

    Rafferty, Brian T.; Janal, Malvin N.; Zavanelli, Ricardo A.; Silva, Nelson R. F. A.; Rekow, E. Dianne; Thompson, Van P.; Coelho, Paulo G.

    2009-01-01

    Objective To evaluate the effects of clinically relevant variables on the maximum principal stress (MPS) in the veneer layer of an anatomically correct veneer-core-cement-tooth model. Methods The average dimensions of a mandibular first molar crown were imported into CAD software; a tooth preparation was modeled by reducing the proximal walls by 1.5 mm and the occlusal surface by 2.0 mm. ‘Crown systems’ were composed by varying characteristics of a cement layer, structural core, and veneer solid, all designed to fit the tooth preparation. The main and interacting effects of proximal wall height reduction, core material, core thickness, cement modulus, cement thickness, and load position on the maximum stress distribution were derived from a series of nite element models and analyzed in a factorial analysis of variance. Results The average MPS in the veneer layer over the 64 models was 488 MPa (range= 248 to 840 MPa). MPS increased significantly with the addition of horizontal load components and with increasing cement thickness. In addition, MPS levels varied as a function of interactions between: proximal wall height reduction and load position; load position and cement thickness; core thickness and cement thickness; cement thickness and proximal wall height reduction; and core thickness, cement thickness and proximal wall height reduction. Conclusion Rational design of veneered structural ceramics must consider the complex geometry of the crown-tooth system and integrate the in uence of both the main effects and interactions among design parameters. PMID:19857888

  11. Low-speed aerodynamic characteristics of a 14-percent-thick NASA phase 2 supercritical airfoil designed for a lift coefficient of 0.7

    NASA Technical Reports Server (NTRS)

    Harris, C. D.; Mcghee, R. J.; Allison, D. O.

    1980-01-01

    The low speed aerodynamic characteristics of a 14 percent thick supercritical airfoil are documented. The wind tunnel test was conducted in the Low Turbulence Pressure Tunnel. The effects of varying chord Reynolds number from 2,000,000 to 18,000,000 at a Mach number of 0.15 and the effects of varying Mach number from 0.10 to 0.32 at a Reynolds number of 6,000,000 are included.

  12. External linkage tie permits reduction in ducting system flange thickness

    NASA Technical Reports Server (NTRS)

    Pfleger, R. O.

    1966-01-01

    External linkage tie reduces flange thickness and increases seal efficiency in high pressure ducting and piping systems. The linkage transmits the pressure separating load to the tube wall behind the flange allowing the flange to support only the seal.

  13. 'Stucco' Walls

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This projected mosaic image, taken by the microscopic imager, an instrument located on the Mars Exploration Rover Opportunity 's instrument deployment device, or 'arm,' shows the partial clotting or cement-like properties of the sand-sized grains within the trench wall. The area in this image measures approximately 3 centimeters (1.2 inches) wide and 5 centimeters (2 inches) tall.(This image also appears as an inset on a separate image from the rover's navigation camera, showing the location of this particular spot within the trench wall.)

  14. Wall Covering

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The attractive wall covering shown below is one of 132 styles in the Mirror Magic II line offered by The General Tire & Rubber Company, Akron, Ohio. The material is metallized plastic fabric, a spinoff from space programs. Wall coverings are one of many consumer applications of aluminized plastic film technology developed for NASA by a firm later bought by King-Seeley Thermos Company, Winchester, Massachusetts, which now produces the material. The original NASA use was in the Echo 1 passive communications satellite, a "space baloon" made of aluminized mylar; the high reflectivity of the metallized coating enabled relay of communications signals from one Earth station to another by "bouncing" them off the satellite. The reflectivity feature also made the material an extremely efficient insulator and it was subsequently widely used in the Apollo program for such purposes as temperature control of spacecraft components and insulation of tanks for fuels that must be maintained at very low temperatures. I Used as a wall covering, the aluminized material offers extra insulation, reflects light and I resists cracking. In addition to General Tire, King-Seeley also supplies wall covering material to Columbus Coated Fabrics Division of Borden, Incorporated, Columbus, Ohio, among others.

  15. Wall Art

    ERIC Educational Resources Information Center

    McGinley, Connie Q.

    2004-01-01

    The author of this article, an art teacher at Monarch High School in Louisville, Colorado, describes how her experience teaching in a new school presented an exciting visual challenge for an art teacher--monotonous brick walls just waiting for decoration. This school experienced only minimal instances of graffiti, but as an art teacher, she did…

  16. Component systems enhancement: Reduced girth seam weldments for heavy walled vessels: Final report

    SciTech Connect

    Not Available

    1987-08-01

    Since many coal gasification processes require heavy-wall pressure vessels as an integral part of the process train, new concepts to reduce the cost and schedule for manufacturing and constructing heavy-wall pressure vessels will result in overall plant cost savings. The results of this research demonstrate that it is feasible to use a reduced girth seam weldment design equal to two-thirds of the nominal vessel wall thickness. This reduction in welding thickness greatly reduces the overall cost of heavy-wall vessels. This report summarizes results of nonlinear finite element analysis and scale model testing of various reduced girth seam details demonstrating that the local reduced thickness does not significantly reduce the ultimate pressure capacity of a heavy-wall vessel. The report also summarizes estimated cost and schedule savings for a typical coal gasification vessel that uses a reduced girth seam detail. In addition, estimated overall plant construction cost savings and overall plant operating and maintenance cost savings are presented. 11 refs., 1 fig., 6 tabs.

  17. Wall-drag measurements of smooth- and rough-wall turbulent boundary layers using a floating element

    NASA Astrophysics Data System (ADS)

    Baars, W. J.; Squire, D. T.; Talluru, K. M.; Abbassi, M. R.; Hutchins, N.; Marusic, I.

    2016-05-01

    The mean wall shear stress, overline{τ }_w, is a fundamental variable for characterizing turbulent boundary layers. Ideally, overline{τ }_w is measured by a direct means and the use of floating elements has long been proposed. However, previous such devices have proven to be problematic due to low signal-to-noise ratios. In this paper, we present new direct measurements of overline{τ }_w where high signal-to-noise ratios are achieved using a new design of a large-scale floating element with a surface area of 3 m (streamwise) × 1 m (spanwise). These dimensions ensure a strong measurement signal, while any error associated with an integral measurement of overline{τ }_w is negligible in Melbourne's large-scale turbulent boundary layer facility. Wall-drag induced by both smooth- and rough-wall zero-pressure-gradient flows are considered. Results for the smooth-wall friction coefficient, C_f ≡ overline{τ }_w/q_{∞}, follow a Coles-Fernholz relation C_f = [ 1/κ ln ( Re_{θ }) + C] ^{-2} to within 3 % (κ = 0.38 and C = 3.7) for a momentum thickness-based Reynolds number, Re_{θ } > 15{,}000. The agreement improves for higher Reynolds numbers to <1 % deviation for Re_{θ } > 38{,}000. This smooth-wall benchmark verification of the experimental apparatus is critical before attempting any rough-wall studies. For a rough-wall configuration with P36 grit sandpaper, measurements were performed for 10{,}500< Re_{θ } < 88{,}500, for which the wall-drag indicates the anticipated trend from the transitionally to the fully rough regime.

  18. Nonlinear Thermal Analyses of a Liquid Hydrogen Tank Wall

    NASA Technical Reports Server (NTRS)

    Smeltzer, Stanley S., III; Waters, W. Allen, Jr.

    2003-01-01

    A thermal evaluation of a composite tank wall design for a liquid hydrogen tank was performed in the present study. The primary focus of the current effort was to perform one-dimensional, temperature nonlinear, transient thermal analyses to determine the through-the-thickness temperature profiles. These profiles were used to identify critical points within the flight envelope that could have detrimental effects on the adhesive bondlines used in the construction of the tank wall. Additionally, this paper presents the finite element models, analysis strategies, and thermal analysis results that were determined for several vehicle flight conditions. The basic tank wall configuration used to perform the thermal analyses consisted of carbon-epoxy facesheets and a Korex honeycomb core sandwich that was insulated with an Airex cryogenic foam and an Alumina Enhanced Thermal Barrier (AETB-12). Nonlinear, transient thermal analyses were conducted using the ABAQUS finite element code. Tank wall models at a windward side location on the fuel tank were analyzed for three basic flight conditions: cold-soak (ground-hold), ascent, and re-entry. Additionally, three ambient temperature boundary conditions were applied to the tank wall for the cold-soak condition, which simulated the launch pad cooldown process. Time-dependent heating rates were used in the analyses of the ascent and reentry segments of the flight history along with temperature dependent material properties. The steady-state through-the-thickness temperature profile from the cold-soak condition was used as the initial condition for the ascent analyses. Results from the nonlinear thermal analyses demonstrated very good correlation with results from similar models evaluated by Northrop- Grumman using a different analysis tool. Wall through-the-thickness temperature gradients as a function of flight time were obtained for future incorporation into a full-scale thermostructural analysis to evaluate the adhesive bondlines

  19. Statistical analysis of the mechanical properties of thin walled ductile iron castings

    SciTech Connect

    Schrems, Karol K.; Hawk, Jeffrey A.; Dogan, Omer N.; Druschitz, A.P.

    2003-01-01

    Ductile iron castings have long been used in the automotive market. Ductile iron is inexpensive to produce and has desirable fracture resistance and mechanical properties. However, the weight of ductile iron is driving an effort to reduce wall thickness in order to increase fuel economy. Traditionally, cast iron has been cast into thick, bulky shapes. Reducing the section size of cast iron can be done, but pushes foundry practice into new areas. A consortium of foundries, foundry suppliers, and automotive manufacturers has been pursuing the use of thin walled ductile cast iron. This paper investigates the mechanical behavior of three experimental heats of thin-wall castings in order to evaluate property trends and limits. Castings as thin as 1.7 mm (0.07 in) have been successfully cast. The study was designed to investigate the effects of thickness and different casting heats on the dependent variables of ultimate tensile strength, yield strength, elongation-to-failure, reduction in area, and hardness. The ultimate tensile strength of the castings is found to increase as the casting thickness decreases. Conversely, the elongation-to-failure is found to decrease as the casting thickness decreases. Heat-to-heat differences were found, but they were usually within the scatter of the data.

  20. Artificial Rock Climbing Walls--Innovative Adventure Environments.

    ERIC Educational Resources Information Center

    Attarian, Aram

    1989-01-01

    The history, advantages, and disadvantages of artificial rock climbing walls (used to instruct individuals in the sport of rock climbing) are discussed. Additional topics include designing an artificial wall, types of walls, various uses, and risk management. (IAH)

  1. Reducing the uncertainties associated with using the ASHRAE zone method for R-value calculations of metal frame walls

    SciTech Connect

    Kosny, J.; Christian, J.E.

    1995-12-31

    Several authors report the accuracy of the ASHRAE zone method of R-value calculation of metal frame walls as unsatisfactory. A series of more than 1,000 two-dimensional computer simulations was conducted for several metal frame wall configurations. Several wall design parameters, such as stud spacing, stud (depth) size, stud flange size, stud metal thickness, thermal resistance of cavity insulation, and thermal resistance of exterior sheathing, were considered during modeling. This allowed the influence of each above-mentioned designing parameter on metal frame wall thermal performance to be assessed. Wall R-values calculated by the ASHRAE zone method were compared with the results of the computer simulation. The comparison showed that the differences in the thermal calculations are caused by the metal stud zone area estimation. Based on results of finite-difference thermal modeling and regression analysis, a new, more precise technique of estimating zones of thermal anomalies caused by metal studs for metal frame walls was developed. The effects of several wall design parameters were calculated. An improved method of R-value predictions for metal frame walls is proposed.

  2. External Insulation of Masonry Walls and Wood Framed Walls

    SciTech Connect

    Baker, P.

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1" to 1 1/2"), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  3. External Insulation of Masonry Walls and Wood Framed Walls

    SciTech Connect

    Baker, P.

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1” to 1 ½”), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  4. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the following formula, whichever is greater: t = 1.83 Pd / 2SE Where: t = minimum thickness of plate.... (a) The minimum wall thickness, after forming, of the inner shell and any 2:1 ellipsoidal head for the inner tank must be that specified in § 179.401-1, or that calculated by the following...

  5. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... the following formula, whichever is greater: t = 1.83 Pd / 2SE Where: t = minimum thickness of plate.... (a) The minimum wall thickness, after forming, of the inner shell and any 2:1 ellipsoidal head for the inner tank must be that specified in § 179.401-1, or that calculated by the following...

  6. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the following formula, whichever is greater: t = 1.83 Pd / 2SE Where: t = minimum thickness of plate.... (a) The minimum wall thickness, after forming, of the inner shell and any 2:1 ellipsoidal head for the inner tank must be that specified in § 179.401-1, or that calculated by the following...

  7. LTCC Thick Film Process Characterization

    DOE PAGESBeta

    Girardi, M. A.; Peterson, K. A.; Vianco, P. T.

    2016-05-01

    Low temperature cofired ceramic (LTCC) technology has proven itself in military/space electronics, wireless communication, microsystems, medical and automotive electronics, and sensors. The use of LTCC for high frequency applications is appealing due to its low losses, design flexibility and packaging and integration capability. Moreover, we summarize the LTCC thick film process including some unconventional process steps such as feature machining in the unfired state and thin film definition of outer layer conductors. The LTCC thick film process was characterized to optimize process yields by focusing on these factors: 1) Print location, 2) Print thickness, 3) Drying of tapes and panels,more » 4) Shrinkage upon firing, and 5) Via topography. Statistical methods were used to analyze critical process and product characteristics in the determination towards that optimization goal.« less

  8. Individual progression of carotid intima media thickness as a surrogate for vascular risk (PROG-IMT): Rationale and design of a meta-analysis project

    PubMed Central

    Lorenz, Matthias W.; Bickel, Horst; Bots, Michiel L.; Breteler, Monique M.B.; Catapano, Alberico L.; Desvarieux, Moise; Hedblad, Bo; Iglseder, Bernhard; Johnsen, Stein Harald; Juraska, Michal; Kiechl, Stefan; Mathiesen, Ellisiv B.; Norata, Giuseppe D.; Grigore, Liliana; Polak, Joseph; Poppert, Holger; Rosvall, Maria; Rundek, Tatjana; Sacco, Ralph L.; Sander, Dirk; Sitzer, Matthias; Steinmetz, Helmuth; Stensland, Eva; Willeit, Johann; Witteman, Jacqueline; Yanez, David; Thompson, Simon G.

    2013-01-01

    Carotid intima media thickness (IMT) progression is increasingly used as a surrogate for vascular risk. This use is supported by data from a few clinical trials investigating statins, but established criteria of surrogacy are only partially fulfilled. To provide a valid basis for the use of IMT progression as a study end point, we are performing a 3-step meta-analysis project based on individual participant data. Objectives of the 3 successive stages are to investigate (1) whether IMT progression prospectively predicts myocardial infarction, stroke, or death in population-based samples; (2) whether it does so in prevalent disease cohorts; and (3) whether interventions affecting IMT progression predict a therapeutic effect on clinical end points. Recruitment strategies, inclusion criteria, and estimates of the expected numbers of eligible studies are presented along with a detailed analysis plan. PMID:20435179

  9. Two Thick Microwave Dichroic Panels

    NASA Technical Reports Server (NTRS)

    Epp, Larry W.; Chen, Jacqueline C.; Stanton, Philip H.; Jorgenson, Roy E.

    1994-01-01

    Cross-shaped apertures enable relatively tight packing, eliminating some grating lobes. Two panels made of thin, honey-comblike metal walls constitute planar arrays of waveguidelike apertures designed to satisfy special requirements with respect to microwave transmittance and reflectance. Considered for use in multiplexing signals at various frequencies in microwave communication system. Both panels required to exhibit low insertion loss. Angle of incidence 30 degrees.

  10. Ballistic Limit Equation for Single Wall Titanium

    NASA Technical Reports Server (NTRS)

    Ratliff, J. M.; Christiansen, Eric L.; Bryant, C.

    2009-01-01

    Hypervelocity impact tests and hydrocode simulations were used to determine the ballistic limit equation (BLE) for perforation of a titanium wall, as a function of wall thickness. Two titanium alloys were considered, and separate BLEs were derived for each. Tested wall thicknesses ranged from 0.5mm to 2.0mm. The single-wall damage equation of Cour-Palais [ref. 1] was used to analyze the Ti wall's shielding effectiveness. It was concluded that the Cour-Palais single-wall equation produced a non-conservative prediction of the ballistic limit for the Ti shield. The inaccurate prediction was not a particularly surprising result; the Cour-Palais single-wall BLE contains shield material properties as parameters, but it was formulated only from tests of different aluminum alloys. Single-wall Ti shield tests were run (thicknesses of 2.0 mm, 1.5 mm, 1.0 mm, and 0.5 mm) on Ti 15-3-3-3 material custom cut from rod stock. Hypervelocity impact (HVI) tests were used to establish the failure threshold empirically, using the additional constraint that the damage scales with impact energy, as was indicated by hydrocode simulations. The criterion for shield failure was defined as no detached spall from the shield back surface during HVI. Based on the test results, which confirmed an approximately energy-dependent shield effectiveness, the Cour-Palais equation was modified.

  11. Nondestructive testing of welds on thin-walled tubing

    NASA Technical Reports Server (NTRS)

    Hagemaier, D. J.; Posakony, G. J.

    1969-01-01

    Special ultrasonic search unit, or transducer assembly, reliably inspects the quality of melt-through welds of fusion welded tubing couplers for hydraulic lines. This instrumentation can also be used to detect faulty braze bonds in thin-walled, small diameter joints and wall thickness of thin-walled metal tubing.

  12. Corneal thickness in glaucoma.

    PubMed

    De Cevallos, E; Dohlman, C H; Reinhart, W J

    1976-02-01

    The central corneal stromal thickness of patients with open angle glaucoma, secondary glaucoma (the majority aphakic), or a history of unilateral acute angle closure glaucoma were measured and compared with the stromal thickness of a group of normal patients. In open angle glaucoma, there was a small but significant increase in the average stromal thickness. This thickness increase was, in all likelihood, due to an abnormal function of the endothelium in this disease since the level of the intraocular pressure did not seem to be a factor. There was no correlation between stromal thickness and duration of the glaucoma or type of anti-glaucomatous medication. Most cases of secondary glaucome, controlled medically or not, had markedly increased corneal thickness, again, most likely, due to endothelial damage rather than to level of intraocular pressure. After an angle closure attack, permanent damage to the cornea was found to be rare. PMID:1247273

  13. A hybrid model of support vector regression with genetic algorithm for forecasting adsorption of malachite green onto multi-walled carbon nanotubes: central composite design optimization.

    PubMed

    Ghaedi, M; Dashtian, K; Ghaedi, A M; Dehghanian, N

    2016-05-11

    The aim of this work is the study of the predictive ability of a hybrid model of support vector regression with genetic algorithm optimization (GA-SVR) for the adsorption of malachite green (MG) onto multi-walled carbon nanotubes (MWCNTs). Various factors were investigated by central composite design and optimum conditions was set as: pH 8, 0.018 g MWCNTs, 8 mg L(-1) dye mixed with 50 mL solution thoroughly for 10 min. The Langmuir, Freundlich, Temkin and D-R isothermal models are applied to fitting the experimental data, and the data was well explained by the Langmuir model with a maximum adsorption capacity of 62.11-80.64 mg g(-1) in a short time at 25 °C. Kinetic studies at various adsorbent dosages and the initial MG concentration show that maximum MG removal was achieved within 10 min of the start of every experiment under most conditions. The adsorption obeys the pseudo-second-order rate equation in addition to the intraparticle diffusion model. The optimal parameters (C of 0.2509, σ(2) of 0.1288 and ε of 0.2018) for the SVR model were obtained based on the GA. For the testing data set, MSE values of 0.0034 and the coefficient of determination (R(2)) values of 0.9195 were achieved. PMID:27119755

  14. Designed synthesis of multi-walled carbon nanotubes@Cu@MoS2 hybrid as advanced electrocatalyst for highly efficient hydrogen evolution reaction

    NASA Astrophysics Data System (ADS)

    Li, Feng; Li, Jing; Lin, Xiaoqing; Li, Xinzhe; Fang, Yiyun; Jiao, Lixin; An, Xincai; Fu, Yan; Jin, Jun; Li, Rong

    2015-12-01

    Design and synthesis of non-precious-metal catalyst for efficient electrochemical transformation of water to molecular hydrogen in acid environments is of paramount importance in reducing energy losses during the water splitting process. Here, the hybrid material of MoS2-coated Cu loaded on the multi-walled carbon nanotubes (MWCNTs@Cu@MoS2) was synthesized using chemical process and hydrothermal method. It was found that the participation of MWCNTs and Cu nanoparticles not only improved the electrical conductivity of the catalyst, but also further enhanced the catalytic activity by synergistic effect with edge-exposed MoS2-coating. Electrochemical experiments demonstrated that the catalyst exhibited excellent hydrogen evolution reaction (HER) activity with large cathode currents (small overpotential of 184 mV for 10 mA cm-2 current density) and a Tafel slope as small as 62 mV per decade. Furthermore, it was discovered that the current density of this composite catalyst had a little decrease after the continual 1000 cycling, which showed the catalyst had a high stability in the recycling process. These findings confirmed that this catalyst was a useful and earth-abundant material for water splitting.

  15. Development of Novel Drug and Gene Delivery Carriers Composed of Single-Walled Carbon Nanotubes and Designed Peptides With PEGylation.

    PubMed

    Ohta, Takahisa; Hashida, Yasuhiko; Yamashita, Fumiyoshi; Hashida, Mitsuru

    2016-09-01

    Single-walled carbon nanotubes (SWCNTs) attract great interest in biomedical applications including drug and gene delivery. In this study, we developed a novel delivery system using SWCNTs associated with designed polycationic and amphiphilic peptides. Wrapping of SWCNTs with H-(-Lys-Trp-Lys-Gly-)7-OH [(KWKG)7] resulted in stable dispersion in water, but the composite aggregated in the buffered solution. This dispersion instability was also evident in a cell culture medium with fetal bovine serum. To improve the aqueous dispersibility, the SWCNTs-(KWKG)7 composite was further modified with polyethylene glycol (PEG) at the lysine residues via amide bond formation and the highest modification extent of 13.3% of the amino groups which corresponded to 2 PEG chains in each peptide molecule was achieved with fluorescein isothiocyanate-labeled carboxyl-PEG12. The uptake of the SWCNTs composite by A549 human lung adenocarcinoma epithelial cells was evaluated by visual observation and fluorescence activated cell sorting analysis for SWCNTs wrapped with a mixture of (KWKG)7 with PEGylation and H-(-Cys-Trp-Lys-Gly-)-OH-(KWKG)6 [CWKG(KWKG)6] labeled with fluorescent boron-dipyrromethene tetramethylrhodamine and 7-fold higher uptake comparing with SWCNTs-peptide composite without PEGylation was obtained suggesting the importance of dispersibility in addition to a cationic charge. The superior potential of SWCNTs composites assisted by polycationic and amphiphilic peptides with PEGylation was thus demonstrated. PMID:27179670

  16. A thick homogeneous vegetated cover design proves cost - and schedule-effective for the reclamation of uranium mills sites near Spokane, Washington

    SciTech Connect

    Blacklaw, J.; Robertson, G.; Stoffel, D.; Ahmad, J.; Fordham, E.

    1997-08-01

    The Washington State Department of Health (WDOH) has licensed two medium sized uranium mills with tailings impoundments covering 28 and 40 hectares (70 and 100 acres), respectively, The uranium mill licensees have submitted closure and reclamation plans to the state, and site-specific conditions have determined the closure design features, Conventional uranium mill cover designs usually incorporate an overall cap of one to three meters, which includes a low-permeability clay barrier layer. A technical evaluation of several uranium mill facilities that used this design was published in the fall of 1994 and reported that unexpected vegetation root damage had occurred in the low-permeability clay (or bentonite amended) barrier layers. The technical report suggested that the low-permeability design feature at some sites could be compromised within a very short time and the regulatory goal of 1,000 years performance might not be achieved. In October 1994, WDOH sponsored a technical forum meeting to consider design alternatives to address these reliability concerns. Representatives from the federal government, nuclear industry, licensees, engineering firms, and state regulatory agencies attended the workshop. Risk factors considered in the evaluation of the uranium mill reclamation plans include: (1) radon gas emanation through the cover (the air pathway), and (2) migration of hazardous and/or radioactive constituents (the groundwater pathway). Additional design considerations include site structural stability, longevity of 1,000 years, and no active (ongoing) maintenance. 9 refs.

  17. Thickness quantization in a reorientation transition

    NASA Astrophysics Data System (ADS)

    Venus, David; He, Gengming; Winch, Harrison; Belanger, Randy

    The reorientation transition of an ultrathin film from perpendicular to in-plane magnetization is driven by a competition between shape and surface anisotropy. It is accompanied by a ''stripe'' domain structure that evolves as the reorientation progresses. Often, an n layer film has stable perpendicular magnetization and an n+1 layer film has stable in-plane magnetization. If the domain walls are not pinned, the long-range stripe domain pattern averages over this structure so that the transition occurs at a non-integer layer thickness. We report in situ experimental measurements of the magnetic susceptibility (via MOKE) of the reorientation transition in Fe/2 ML Ni/W(110) films as a function of thickness as they are deposited at room temperature. In addition to a peak at the reorientation transition, we observe a strong precursor due to thickness quantization in atomic layers. This peak is described quantitatively by the response of small islands of thickness 3 layers with in-plane anisotropy in a sea of 2 layers Fe with perpendicular anisotropy. The fitted parameters give an estimate of the island size at which the response disappears. This size corresponds to a domain wall thickness, so that the islands become locally in-plane, demonstrating the self-consistency of the model.

  18. Elastic torsional buckling of thin-walled composite cylinders

    NASA Technical Reports Server (NTRS)

    Marlowe, D. E.; Sushinsky, G. F.; Dexter, H. B.

    1974-01-01

    The elastic torsional buckling strength has been determined experimentally for thin-walled cylinders fabricated with glass/epoxy, boron/epoxy, and graphite/epoxy composite materials and composite-reinforced aluminum and titanium. Cylinders have been tested with several unidirectional-ply orientations and several cross-ply layups. Specimens were designed with diameter-to-thickness ratios of approximately 150 and 300 and in two lengths of 10 in. and 20 in. The results of these tests were compared with the buckling strengths predicted by the torsional buckling analysis of Chao.

  19. Pavement thickness evaluation using ground penetrating radar

    NASA Astrophysics Data System (ADS)

    Harris, Dwayne Arthur

    Accurate knowledge of pavement thickness is important information to have both at a network and project level. This information aids in pavement management and design. Much of the time this information is missing, out of date, or unknown for highway sections. Current technologies for determining pavement thickness are core drilling, falling weight deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavement thickness information; however, it is also time consuming, labor intensive, intrusive to traffic, destructive, and limited in coverage. FWD provides nondestructive estimates of both a surface thickness and total pavement structure thickness, including pavement, base and sub-base. On the other hand, FWD is intrusive to traffic and affected by the limitations and assumptions the method used to estimate thickness. GPR provides pavement surface course thickness estimates with excellent data coverage at highway speed. Yet, disadvantages include the pavement thickness estimation being affected by the electrical properties of the pavement, limitations of the system utilized, and heavy post processing of the data. Nevertheless, GPR has been successfully utilized by a number of departments of transportation (DOTs) for pavement thickness evaluation. This research presents the GPR thickness evaluation methods, develops GPRPAVZ the software used to implement the methodologies, and addresses the quality of GPR pavement thickness evaluation.

  20. Wall-thickness changes predicted in hollow-drawn tubing

    NASA Technical Reports Server (NTRS)

    Flinn, J. E.; Mura, T.

    1969-01-01

    Hollow-tube drawing or tube sinking theory is based on the concept of continuous distribution of dislocations. Material composition, parameter influence, and die-angle are determining factors in derivation of the theoretical model.