Thin walls in regions with vacuum energy

Energy Technology Data Exchange (ETDEWEB)

Garfinkle, D [Florida Univ., Gainesville, FL (USA). Dept. of Physics; Vuille, C [Embry-Riddle Aeronautical Univ., Prescott, AZ (USA). Dept. of Math/Physical Science

1989-12-01

The motion of a thin wall is treated in the case where the regions on either side of the wall have vacuum energy. This treatment generalises previous results involving domain walls in vacuum and also previous results involving the properties of false vacuum bubbles. The equation of state for a domain wall is{tau} = {sigma} where {tau} is the tension in the wall and {sigma} is the energy density. We consider the motion of a more general class of walls having equation of state {tau}{Gamma}{sigma} with 0{le}{Gamma}{le}1. Spherically symmetric and planar symmetric walls are examined. We also find the global structure of the wall spacetime. (author).

Linear motion feed through with thin wall rubber sealing element

Science.gov (United States)

Mikhailov, V. P.; Deulin, E. A.

2017-07-01

The patented linear motion feedthrough is based on elastic thin rubber walls usage being reinforced with analeptic string fixed in the middle part of the walls. The pneumatic or hydro actuators create linear movement of stock. The length of this movement is two times more the rubber wall length. This flexible wall is a sealing element of feedthrough. The main advantage of device is negligible resistance force that is less then mentioned one in sealing bellows that leads to positioning error decreasing. Nevertheless, the thin wall rubber sealing element (TRE) of the feedthrough is the main unreliable element that was the reason of this element longevity research. The theory and experimental results help to create equation for TRE longevity calculation under vacuum or extra high pressure difference action. The equation was used for TRE longevity determination for hydraulic or vacuum equipment realization also as it helps for gas flow being leaking through the cracks in thin walls of rubber sealing element of linear motion feedthrough calculation.

A study on the root cause identification of local wall thinning caused by deflected turbulent flow inside orifice of carbon steel components

International Nuclear Information System (INIS)

Park, S. H.; Kim, K. H.; Hwang, K. M.

2010-01-01

When components made of carbon steel in nuclear, fossil, and industry plants are exposed to flowing fluid, wall thinning caused by FAC (flow accelerated corrosion) can be generated and eventually ruptured at the portion of pressure boundary. A study to identify the locations generating local wall thinning and to disclose turbulence coefficients related to the local wall thinning was performed. Experiments and numerical analyses for orifice of down-scaled piping components were performed and the results were compared. Based on the results that the flow behaviors inside piping components can be simulated by numerical analysis, numerical analyses for magnified models to actual size of plants were performed. To disclose the relationship between turbulence coefficients and local thinning rate, numerical analyses were preformed for orifice components included in the main feedwater systems. The turbulence coefficients based on the numerical analyses were compared with the local wear rate based on the measured data. From the comparison of the results, the vertical flow velocity component (Vr) flowing to the wall after separating in the wall due to the geometrical configuration and colliding with the wall directly at an angle of some degree was analogous to the configuration of local wall thinning. (authors)

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

Science.gov (United States)

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.

Nuclear Power Plants Secondary Circuit Piping Wall-Thinning Management in China

International Nuclear Information System (INIS)

Zhong Zhimin; Li Jinsong; Zheng Hui

2012-01-01

Research and field feedbacks showed that nuclear power plants secondary circuit steam and water piping are more sensitive than that of fuel plant to the attack of flow-accelerated corrosion (FAC). FAC, Liquid droplet impingement or cavitation erosion will cause secondary circuit piping local wall-thinning in NPPs. Without effective management, the wall-thinning in those high energy piping will cause leakage or pipe rupture during nuclear power plant operation, more seriously cause unplanned shut down, injured and fatality, or heavy economic losses. This paper briefly introduces the history, development and state of the art of secondary circuit piping wall-thinning management in China NPPs. Then, the effectiveness of inspection grid size selecting was analyzed in detail based on field feedbacks. EPRI recommendatory inspection grid, JSME code recommendatory grid and plant specific inspection grid were compared and the detection probabilities of local wall-thinning were estimated. Then, the development and application of NPPs Secondary Circuit Piping Wall Thickness Management Information System, developed, operated and maintained by our team, was briefly introduced and the statistical analysis results of 11 PWR units were shared. It was conclude that the long term, systemic, effective wall-thinning management strategy of high energy piping was very important to the safety and economic operation of NPPs. Furthermore, take into account the actual situation of China nuclear power plants, some advice and suggestion on developing effective nuclear power plant secondary circuit steam and water piping wall-thinning management system are put forward from code development, design and manufacture, operation management, pipeline and locations selection, inspection method selection and application, thickness measurement result evaluation, residual life predication and decision making, feedbacks usage, personnel training and etc. (author)

Effect of length of thinning area on the failure behavior of carbon steel pipe containing a defect of wall thinning

International Nuclear Information System (INIS)

Kim, Jin Weon; Park, Chi Yong

2003-01-01

The present study performed pipe failure tests using 102 mm-Sch. 80 carbon steel pipe with various simulated wall thinning defects, to investigate the effect of axial length of wall thinning and internal pressure on the failure behavior of pipe thinned by flow accelerated corrosion (FAC). The tests were conducted under loading conditions of four-point bending with and without internal pressure. The results showed that a failure mode of pipe with a defect depended on the magnitude of internal pressure and axial thinning length as well as stress type and thinning depth and circumferential angle. Both load carrying capability (LCC) and deformation capability (DC) were depended on stress type in the thinning area and dimensions of thinning defect. For applying tensile stress to the thinned area, the dependence of LCC on the axial length of wall thinning was determined by circumferential thinning angle, and the DC was proportionally increased with increase in axial length of wall thinning regardless of the circumferential angle. For applying compressive stress to thinned area, however, the LCC was decreased with increase in axial length of the thinned area. Also, the effect of internal pressure on failure behavior was characterized by failure mode of thinned pipe, and it promoted crack occurrence and mitigated a local buckling of the thinned area

The precision cutting control research of automotive stainless steel thin wall pipe

Directory of Open Access Journals (Sweden)

Jin Lihong

2015-01-01

Full Text Available Stainless steel thin-walled tube are widely used in automobile industry at present, but as a result of thin wall pipe is poor strength and poor rigidity,which lead to deformation, shaped differencer and other problems in the process, it is hard to ensure the processing quality of parts. This paper proposes a method of thin stainless steel thin wall pipe cutting process in vehicle, greatly improved the problems and technical difficulties in the traditional process, the main research is about the cutting system and the hydraulic fixture design, obtained under low cost circumstances, it can realize high precision stainless steel pipes, high degree of automation to automatic cutting,simplified operation steps at the same time, increased the applicability of the system, provided a kind of advanced stainless steel thin wall pipe cutting device for the small and medium-sized enterprises.

Study on Mechanical Behavior of Thin-walled Member during Precision Straightening Process

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Ben Guan

2014-09-01

Full Text Available This paper introduces the mechanical behavior of precise straightening thin-walled members systematically. As a result of its cross section characteristics of the thin-walled members, traditional straightening theory does not work well in the straightening process of this kind of metal bar stock. Considering the stress evolvement of section during the straightening process, a model was built to analysis the straightening process like thin-walled member with great section height. By making a thorough analysis of the straightening process, the section deformation law and the relationship between sectional distortion and straightening parameters has been mastered. An analytical model was built for macroscopic energetics parameters of the straightening process and the parameters was optimized based on this model. Then loading mode of thin-walled member straightening was discussed.

Solidified structure of thin-walled titanium parts by vertical centrifugal casting

Directory of Open Access Journals (Sweden)

Wu Shiping

2011-05-01

Full Text Available The solidified structure of the thin-walled and complicated Ti-6Al-4V castings produced by the vertical centrifugal casting process was studied in the present work. The results show that the wall thickness of the section is featured with homogeneously distributed fine equiaxial grains, compared with the microstructure of the thick-walled section. The grain size of the castings has a tendency to decrease gradually with the increasing of the centrifugal radius. The inter-lamellar space in thick-walled casting parts is bigger than that of the thin-walled parts, and the profile of inter-lamellar space is not susceptible to the centrifugal radius.

Development of assessment methodology for locally wall-thinned pipe under combined loading

International Nuclear Information System (INIS)

Shim, Do Jun; Kim, Yun Jae; Kim, Young Jin; Park, Chi Yong

2005-01-01

Recently authors have proposed a new method to estimate failure strength of a pipe with local wall thinning subject to either internal pressure or global bending. The proposed method was based on the equivalent stress averaged over the minimum ligament in the locally wall thinned region, and the simple scheme to estimate the equivalent stress in the minimum ligament was proposed, based on the reference stress concept. This paper extends the new method to combined internal pressure and global bending. The proposed method is validated against FE results for various geometries of local wall thinning under combined loading. The effect of internal pressure is also investigated in the present study. Comparison of maximum moments, predicted according to the proposed method, with published full-scale pipe test data for locally wall-thinned pipes under combined internal pressure and global bending, shows good agreement

Wall thinning trend analyses for secondary side piping of Korean NPPs

International Nuclear Information System (INIS)

Hwang, K.M.; Jin, T.E.; Lee, S.H.; Jeon, S.C.

2003-01-01

Since the mid-1990s, nuclear power plants in Korea have experienced wall thinning, leaks, and ruptures of secondary side piping caused by flow-accelerated corrosion (FAC). The pipe failures have increased as operating time progresses. In order to prevent the FAC-induced pipe failures and to develop an effective FAC management strategy, KEPRI and KOPEC have conducted a study for developing systematic FAC management technology for secondary side piping of all Korean nuclear power plants. As a part of the study, FAC analyses were performed using the CHECWORKS code. The analysis results were used to select components for inspection and to determine inspection intervals on each nuclear power plant. This paper describes the introduction of the FAC analysis method and the wall thinning trend analysis results by reactor type, system, and water treatment amine. This paper also represents the site application feasibility for secondary side piping management. The site application feasibility of the analysis results was proven by comparisons of predicted and measured wear rates. (author)

The effect of load-controlled bending load on the failure pressure of wall-thinned pipe elbows

International Nuclear Information System (INIS)

Kim, Jin Weon; Yoon, Min Soo; Park, Chi Yong

2013-01-01

Highlights: • We evaluated bending load effect on the failure pressure of wall-thinned pipe elbows. • Burst tests were conducted on real-scale elbow specimens with local wall thinning. • The tests were performed under combined pressure and load-controlled bending. • Load-controlled bending reduced the failure pressure of wall-thinned elbows. • Bending load effect was significant for opening-mode and intrados wall-thinning case. - Abstract: In this research, burst tests were conducted on real-scale elbow specimens, each with an artificial local wall-thinning defect, under combined internal pressure and constant in-plane bending load, as well as under simple internal pressure, to evaluate the effect of load-controlled bending load on the failure pressure of locally wall-thinned pipe elbows. Ninety-degree, 65A Schedule 80 elbows, with wall-thinning defects in the intrados and extrados, were used as specimens. The bending loads were in-plane opening- and closing-mode bending, applied in load-control mode. The results clearly indicated that a load-controlled in-plane bending load reduced the failure pressure of wall-thinned pipe elbows, in contrast to observations previously made under displacement-controlled bending conditions. The effect of the bending load was more significant for opening-mode than for closing-mode bending, regardless of the wall-thinning location in the elbow. Also, the effect was greater when the wall-thinning defect was located in the intrados region of the elbow, rather than the extrados region. Existing models that have been proposed to evaluate the failure of wall-thinned elbows under simple internal pressure conservatively predicted the failure pressure of elbows subjected to a combined internal pressure and load-controlled bending load

Distortional Mechanics of Thin-Walled Structural Elements

DEFF Research Database (Denmark)

Andreassen, Michael Joachim

In several industries such as civil, mechanical, and aerospace, thin-walled structures are often used due to the high strength and effective use of the materials. Because of the increased consumption there has been increasing focus on optimizing and more detailed calculations. However, finely...... number of degrees of freedom. This means that the classical Vlasov thin-walled beam theory for open and closed cross sections is generalized as part of a semi-discretization process by including distortional displacement fields. A novel finite-element-based displacement approach is used in combination...... by discretization of the cross section are now solved analytically and the formulation is valid without special attention and approximation also for closed single or multi-cell cross sections. Furthermore, the found eigenvalues have clear mechanical meaning, since they represent the attenuation of the distortional...

Gas target with thin wall

International Nuclear Information System (INIS)

Korenchenko, A.S.; Korenchenko, S.M.; Kravchuk, N.P.; Filippov, A.I.; Fursov, A.P.

1992-01-01

The technology of targets manufacture with thin wall diameter 100 mm and lengthwise 700 mm from composition kevlar + epoxy resin is described. The test's results on pressure and vacuum are reported. The created targets are supposed to be used on the installation ARES for an investigation of muons and pions interactions with light nuclei and rare pions decay 'on flying'. 5 refs.; 2 figs.; 2 tabs

The method to design the length of thin-wall flexible rotor

International Nuclear Information System (INIS)

Zhang Yue; Yao Zengzhong; Baigu Lafu

2014-01-01

Thin-wall flexible rotor is frequently used in rotating machinery. For this rotor the vibration is very complex under the working speed. So the composition design is very difficult. In this paper, for a thin-wall flexible rotor, the material and rotor diameter are determined from spatial structure, the working speed is determined from strength of the material, the first bending critical speed is determined from working speed, then the influence of length on the critical speed is researched. According to the influence of critical speed on the vibration, the length design method is researched, the design steps and methods are given, the safety margin of vibration is analysed. Design validity is established by test. The method is generally suitable for thin-wall flexible rotor. (authors)

Safety assessment of pipes with multiple local wall thinning defects under pressure and bending moment

International Nuclear Information System (INIS)

Peng Jian; Zhou Changyu; Xue Jilin; Dai Qiao; He Xiaohua

2011-01-01

The safety assessment of pipes with local wall thinning defects is highly important in engineering. Most attention has been paid on the safety assessment of pipe with single local wall thinning defect, while the studies about multiple local wall thinning defects are not nearly enough. However, the interaction of multiple local wall thinning defects in some conditions is great, and may have a great impact on the safety assessment. In the present standard API 579/ASME FFS, the safety assessment of pipes with multiple local wall thinning defects is given, while as well as the influence of load condition, the influences of arrangement and relative depth of defects are ignored, which may influence the safety assessment considerably. In this paper, the influence of the interaction between multiple local wall thinning defects on the remaining strength of pipes at different arrangements and depths of defects under different load conditions (pressure, tension-bending moment and compression-bending moment) are studied. A quantified index is defined to describe the interaction between defects quantitatively. For different arrangements and relative depths of defects, based on a limit value 0.05 of the quantified index of the interaction between defects, a relatively systematic safety assessment of pipes with multiple local wall thinning defects under different load conditions has been proposed.

SCF analysis of a pressurized vessel-nozzle intersection with wall thinning damage

International Nuclear Information System (INIS)

Qadir, M.; Redekop, D.

2009-01-01

A three-dimensional finite element analysis is carried out of a pressurized vessel-nozzle intersection (tee joint), with wall thinning damage. A convergence-validation study is first carried out for undamaged intersections, in which comparisons are made with previously published work for the stress concentration factor (SCF), and good agreement is observed. A study is then carried out for specific tee joints to examine the effect on the SCF of varying the extent of the wall thinning damage. Finally, a parametric study is conducted in which the SCF is computed for a wide range of tee joints, initially considered undamaged, and then with wall thinning damage.

Thin-walled reinforcement lattice structure for hollow CMC buckets

Science.gov (United States)

de Diego, Peter

2017-06-27

A hollow ceramic matrix composite (CMC) turbine bucket with an internal reinforcement lattice structure has improved vibration properties and stiffness. The lattice structure is formed of thin-walled plies made of CMC. The wall structures are arranged and located according to high stress areas within the hollow bucket. After the melt infiltration process, the mandrels melt away, leaving the wall structure to become the internal lattice reinforcement structure of the bucket.

Tunable Gas Permeability of Polymer-Clay Nano Brick Wall Thin Film Assemblies

Science.gov (United States)

Gamboa, Daniel; Priolo, Morgan; Grunlan, Jaime

2010-03-01

Thin films of anionic natural montmorrilonite (MMT) clay and cationic polyethylenimine (PEI) have been produced by alternately dipping a plastic substrate into dilute aqueous mixtures containing each ingredient. After 40 polymer-clay layers have been deposited, the resulting transparent film exhibits an oxygen transmission rate (OTR) below 0.35 cm^3/m^2 . day when the pH of PEI solution is 10. This low permeability is due to a brick wall nanostructure comprised of completely exfoliated clay bricks in polymeric mortar. This brick wall creates an extremely tortuous path at thicknesses below 250 nm and clay concentration above 80 wt%. A 70-bilayer PEI-MMT assembly has an undetectable OTR (< 0.005 cm^3/m^2 . day), which equates to a permeability below SiOx when multiplied by its film thickness of 231 nm. With optical transparency greater than 86% and the ability to be microwaved, these thin film composites are good candidates for flexible electronics packaging and foil replacement for food.

Evaluation of flow accelerated corrosion by coupled analysis of corrosion and flow dynamics. Relationship of oxide film thickness, hematite/magnetite ratio, ECP and wall thinning rate

International Nuclear Information System (INIS)

Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Uehara, Yasushi; Koshizuka, Seiichi

2011-01-01

Systematic approaches to evaluate flow accelerated corrosion (FAC) are desired before discussing application of countermeasures for FAC. First, future FAC occurrence should be evaluated to identify locations where a higher possibility of FAC occurrence exists, and then, wall thinning rate at the identified FAC occurrence zone is evaluated to obtain the preparation time for applying countermeasures. Wall thinning rates were calculated with two coupled models: 1.static electrochemical analysis and 2.dynamic oxide layer growth analysis. The anodic current density and the electrochemical corrosion potential (ECP) were calculated with the static electrochemistry model based on an Evans diagram. The ferrous ion release rate, determined by the anodic current density, was applied as input for the dynamic double oxide layer model. Some of the dissolved ferrous ion was removed to the bulk water and others precipitated on the surface as magnetite particles. The thickness of oxide layer was calculated with the dynamic oxide layer growth model and then its value was used as input in the electrochemistry model. It was confirmed that the calculated results (corrosion rate and ECP) based on the coupled models were in good agreement with the measured ones. Higher ECP was essential for preventing FAC rate. Moderated conditions due to lower mass transfer coefficients resulted in thicker oxide layer thickness and then higher ECP, while moderated corrosion conditions due to higher oxidant concentrations resulted in larger hematite/magnetite rate and then higher ECP.

Phenomenology of the domain walls in thin ferromagnetic films

International Nuclear Information System (INIS)

Adam, G.

1978-01-01

The basic concepts and the main theoretical methods developed in the study of the domain walls in thin ferromagnetic films are given in this review. First, an insight into the origins and the classification criteria of the conceptually different wall structures is obtained by elementary considerations which are mainly based on the experimentally available data. Then, the more subtle aspect of the wall models dimensionality in soft ferromagnetic films is discussed. Finally, the various theoretical calculation methods of the wall parameters are summarized. (author)

Evaluation of flow accelerated corrosion by coupled analysis of corrosion and flow dynamics (3), relationship of oxide film thickness, hematite/magnetite ratio, ECP and wall thinning rate

International Nuclear Information System (INIS)

Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Uehara, Yasushi; Koshizuka, Seiichi

2009-01-01

Systematic approaches for evaluating flow accelerated corrosion (FAC) are desired before discussing application of countermeasures for FAC. Firstly, future FAC occurrence should be evaluated to identify locations where a higher possibility of FAC occurrence exists, and then, wall thinning rate at the identified FAC occurrence zone is evaluated to obtain the preparation time for applying countermeasures. Wall thinning rates were calculated with the coupled models of static electrochemical analysis and dynamic double oxide layer analysis. Anodic current density and electrochemical corrosion potential (ECP) were calculated with the static electrochemistry model based on an Evans diagram and ferrous ion release rate determined by the anodic current density was applied as input for the dynamic double oxide layer model. Some of the dissolved ferrous ion was removed to the bulk water and others precipitated on the surface as magnetite particles. The thickness of oxide layer was calculated with the dynamic double oxide layer model and then was applied as input for the electrochemistry model. It was confirmed that the calculated results based on the coupled models resulted good agreement with the measured ones. Higher ECP was essential for preventing FAC rate. Moderated conditions due to lower mass transfer coefficients resulted in thicker oxide layer thickness and then higher ECP, while moderated corrosion conditions due to higher oxidant concentrations resulted in larger hematite/magnetite rate and then higher ECP. (author)

Study of Local and Distortional Stability of Thin-Walled Structures

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Imene Mahi

2018-01-01

Full Text Available Thin-walled structures have an increasingly large and growing field of application in the engineering sector, the goal behind using this type of structure is efficiency in terms of resistance and cost, however the stability of its components (the thin walls remains the first aspect of the behavior, and a primordial factor in the design process. The hot rolled sections are known by a consequent post-buckling reserve, cold-formed steel sections which are thin-walled elements also benefit, in this case, it seems essential to take into account the favorable effects of this reserve in to the verification procedure of the resistance with respect to the three modes of failures of this type of structure. The design method that takes into account this reserve of resistance is inevitably the effective width method. The direct strength method has been developed to improve the speed and efficiency of the design of thin-walled profiles. The latter mainly uses the buckling loads (for Local, Distortional and Global mode obtained from a numerical analysis and the resistance curves calibrated experimentally to predict the ultimate load of the profile. Among those, the behavior of a set of Cshaped profiles (highly industrialized is studied, this type of section is assumed to be very prone to modes of local and distortional instability. The outcome of this investigation revealed very relevant conclusions both scientifically and practically.

Fabrication technology for a series of cylindrical thin-wall cavity targets

CERN Document Server

Zheng Yong; Sun Zu Oke; Wang Ming Da; Zhou La; Zhou Zhi Yun

2002-01-01

Cylindrical thin-wall cavity targets have been fabricated to study the behavior of superthermal electrons and their effects on inertial confinement fusion (ICF). Self-supporting cavity targets having adjustable, uniform wall thickness, and low surface roughness were required. This required production of high-quality mandrels, coating them by sputtering or electroplating, developing techniques for measurement of wall thickness and other cavity parameters, improving the uniformity of rotation of the mandrels, and preventing damage to the targets during removal from the mandrels. Details of the fabrication process are presented. Experimental results from the use of these targets are presented. These results, in good agreement with simulations, indicate that the use of thin-wall cavity targets is an effective method for studying superthermal electrons in ICF.

Failure mode and fracture behavior evaluation of pipes with local wall thinning subjected to bending load

International Nuclear Information System (INIS)

Ahn, Seok Hwan; Nam, Ki Woo; Kim, Seon Jin; Kim, Jin Hwan; Kim, Hyun Soo; Do, Jae Yoon

2003-01-01

Fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear power plant. In pipes of energy plants, sometimes, the local wall thinning may result from severe Erosion-Corrosion (E/C) damage. However, the effects of local wall thinning on strength and fracture behaviors of piping system were not well studied. In this paper, the monotonic bending tests were performed of full-scale carbon steel pipes with local wall thinning. A monotonic bending load was applied to straight pipe specimens by four-point loading at ambient temperature without internal pressure. From the tests, fracture behaviors and fracture strength of locally thinned pipe were manifested systematically. The observed failure modes were divided into four types; ovalization, crack initiation/growth after ovalization, local buckling and crack initiating/growth after local buckling. Also, the strength and the allowable limit of piping system with local wall thinning were evaluated

Online monitoring of pipe wall thinning by electromagnetic acoustic resonance method

International Nuclear Information System (INIS)

Urayama, Ryoichi; Takagi, Toshiyuki; Uchimoto, Tetsuya; Kanemoto, Shigeru

2013-01-01

The electromagnetic acoustic resonance (EMAR) method provides accurate and stable evaluation in high temperature environment, and it is an effective tool for online monitoring. In this study, the EMAR method and the superposition of the n-th compression (SNC) for data processing are applied to online monitoring of pipe wall thinning, and the accuracy and reliability of the measurements are demonstrated through field tests using a large-scale corrosion test loop at high temperature. To measure the thickness of pipes with complicated wall thinning, the SNC extracts thickness information from the spectral responses of the EMAR. Results from monitoring test show that EMAR with SNC can evaluate pipe wall thinning with an accuracy of 10 μm at 165degC. In addition, time evaluation of evaluated thickness decreases monotonically all over the test duration, which indicates high stability of this measurement technique. (author)

Development of Wall-Thinning Evaluation Procedure for Nuclear Power Plant Piping—Part 1: Quantification of Thickness Measurement Deviation

Directory of Open Access Journals (Sweden)

Hun Yun

2016-06-01

Full Text Available Pipe wall thinning by flow-accelerated corrosion and various types of erosion is a significant and costly damage phenomenon in secondary piping systems of nuclear power plants (NPPs. Most NPPs have management programs to ensure pipe integrity due to wall thinning that includes periodic measurements for pipe wall thicknesses using nondestructive evaluation techniques. Numerous measurements using ultrasonic tests (UTs; one of the nondestructive evaluation technologies have been performed during scheduled outages in NPPs. Using the thickness measurement data, wall thinning rates of each component are determined conservatively according to several evaluation methods developed by the United States Electric Power Research Institute. However, little is known about the conservativeness or reliability of the evaluation methods because of a lack of understanding of the measurement error. In this study, quantitative models for UT thickness measurement deviations of nuclear pipes and fittings were developed as the first step for establishing an optimized thinning evaluation procedure considering measurement error. In order to understand the characteristics of UT thickness measurement errors of nuclear pipes and fittings, round robin test results, which were obtained by previous researchers under laboratory conditions, were analyzed. Then, based on a large dataset of actual plant data from four NPPs, a quantitative model for UT thickness measurement deviation is proposed for plant conditions.

Assessment of wall-thinning in carbon steel pipe by using laser-generated guided wave

Energy Technology Data Exchange (ETDEWEB)

Kim, Do Yong; Cho, Youn Ho; Lee, Joon Hyun [Pusan National University, School of Mechanical Engineering, Busan (Korea, Republic of)

2010-10-15

The objective of this research is to estimate the crack location and size of a carbon steel pipe by using a laser ultrasound guided wave for the wall thinning evaluation of an elbow. The wall thinning of the carbon steel pipe is one of the most serious problems in nuclear power plants, especially the wall thinning of the carbon steel elbow caused by Flow-Accelerated Corrosion (FAC). Therefore, a non-destructive inspection method of elbow is essential for the nuclear power plants to operate safely. The specimens used in this study were carbon steel elbows, which represented the main elements of real nuclear power plants. The shape of the wall thinning was an oval with a width of 120mm, a length of 80mm, and a depth of 5mm. The L(0,1) and L(0,2) modes variation of the ultrasound guided wave signal is obtained from the response of the laser generation/air-coupled detection ultrasonic hybrid system represent the characteristics of the defect. The trends of these characteristics and signal processing were use dto estimate the size and location of wall thinning

Assessment of wall-thinning in carbon steel pipe by using laser-generated guided wave

International Nuclear Information System (INIS)

Kim, Do Yong; Cho, Youn Ho; Lee, Joon Hyun

2010-01-01

The objective of this research is to estimate the crack location and size of a carbon steel pipe by using a laser ultrasound guided wave for the wall thinning evaluation of an elbow. The wall thinning of the carbon steel pipe is one of the most serious problems in nuclear power plants, especially the wall thinning of the carbon steel elbow caused by Flow-Accelerated Corrosion (FAC). Therefore, a non-destructive inspection method of elbow is essential for the nuclear power plants to operate safely. The specimens used in this study were carbon steel elbows, which represented the main elements of real nuclear power plants. The shape of the wall thinning was an oval with a width of 120mm, a length of 80mm, and a depth of 5mm. The L(0,1) and L(0,2) modes variation of the ultrasound guided wave signal is obtained from the response of the laser generation/air-coupled detection ultrasonic hybrid system represent the characteristics of the defect. The trends of these characteristics and signal processing were use dto estimate the size and location of wall thinning

Radiation transmission type pipe wall thinning detection device and measuring instruments utilizing ionizing radiation

International Nuclear Information System (INIS)

Higashi, Yasuhiko

2009-01-01

We developed the device to detect thinning of pipe thorough heat insulation in Power Plant, etc, even while the plant is under operation. It is necessary to test many parts of many pipes for pipe wall thinning management, but it is difficult within a limited time of the routine test. This device consists of detector and radiation source, which can detect the pipe (less than 500 mm in external diameter, less than 50 mm in thickness) with 1.6%-reproducibility (in a few-minutes measurement), based on the attenuation rate. Operation is easy and effective without removing the heat insulation. We will expand this thinning detection system, and contribute the safety of the Plant. (author)

Nondestructive evaluation of wall thinning occurred under reinforced plate by MFL method

International Nuclear Information System (INIS)

Kikuchi, Hiroaki; Sato, Kaito; Shimizu, Isamu

2013-01-01

Basic study on applying magnetic flux leakage (MFL) method using ac excitation to a nondestructive evaluation of wall thinning occurred under reinforcing plates in nuclear power plants were performed. Frequently, MFL method by means of dc field for exciting specimens is adopted, and only intensity of magnetic flux density is evaluated. On the other hand, MFL with alternating current enable us to utilize not only amplitude of magnetic flux density but also phase difference, which contributes to evaluation with higher accuracy. Here, specimens with slit and pipe with imitated wall thinning are prepared and magnetized using magnetic yoke with ac field, and then the leakage magnetic flux density and the phase difference on the specimen surface are investigated. Additionally, specimens imitated wall thinning occurred under reinforcing plates were investigated by MFL with ac excitation. (author)

Proposal of limit moment equation applicable to planar/non-planar flaw in wall thinned pipes under bending

International Nuclear Information System (INIS)

Tsuji, Masataka; Meshii, Toshiyuki

2011-01-01

Highlights: → A limit moment equation applicable to planar/non-planar flaw of 0 ≤ θ ≤ π found in wall thinned straight pipes was proposed. → An idea to rationally classify planar/non-planar flaw in wall thinned pipes was proposed. → The equation based on the experimental observation focused on the fracture mode. - Abstract: In this paper, a limit bending moment equation applicable to all types of planar and non-planar flaws in wall-thinned straight pipes under bending was proposed. A system to rationally classify the planar/non-planar flaws in wall-thinned pipes was suggested based on experimental observations focused on the fracture mode. The results demonstrate the importance of distinguishing between axial and circumferential long flaws in wall-thinned pipes.

Application of irradiation process for the production of thin wall wires

International Nuclear Information System (INIS)

Saito, E.

1977-01-01

The demand for thin wall crosslinked PVC or polyethylene insulated wires in Japan was about 15,000,000 dollars in value in 1975. Their annual sales in 1980 are estimated at about 40 million dollars which will account for approximately 20% of the sales of all thin wall thermoplastic insulated wires expected for the same year. A comparative study was made of the irradiation process and the chemical process for manufacture of wires with crosslinked PVC or polyethylene insulation. Having found the excellence of the irradiation process an accelerator (500 KeV, 65mA) was installed in 1973 and production was begun of several types of thin wall irradiation crosslinked PVC and polyethylene insulated wires ranging from 0.06 mm 2 to 2.0 mm 2 in the cross-sectional area of conductor, successfully putting them in extensive commercial application. This report compares the irradiation process and the chemical process, properties of several types of irradiation crosslinked PVC, and polyethylene insulated wires and their applications. (author)

Improvement of a wall thinning rate model for liquid droplet impingement erosion. Implementation of liquid film thickness model with consideration of film behavior

International Nuclear Information System (INIS)

Morita, Ryo

2014-01-01

Liquid droplet impingement erosion (LDI) is defined as an erosion phenomenon caused by high-speed droplet attack in a steam flow. Pipe wall thinning by LDI is sometimes observed in a steam piping system of a power plant. As LDI usually occurs very locally and is difficult to detect, predicting LDI location is required for safe operation of power plant systems. Therefore, we have involved in the research program to develop prediction tools that will be used easily in actual power plants. Our previous researches developed a thinning rate evaluation model due to LDI (LDI model) and the evaluation system of the thinning rate and the thinning shape within a practically acceptable time (LDI evaluation system). Though the LDI model can include a cushioning effect of liquid film which is generated on the material surface by droplet impingement as an empirical equation with fluid parameter, the liquid film thickness is not clarified due to complex flow condition. In this study, to improve the LDI model and the LDI evaluation system, an analytical model of the liquid film thickness was proposed with consideration of the liquid film flow behavior on the material surface. The mass balance of the liquid film was considered, and the results of CFD calculations and existing researches were applied to obtain the liquid film thickness in this model. As a result of the LDI evaluation of the new LDI model with liquid film model, improvement of the LDI model was achieved. (author)

Pipe Wall Thinning Evaluation through the Arrival Time Delay of A0 Lamb Wave Using Magnetostrictive Patch Transducers

Energy Technology Data Exchange (ETDEWEB)

Cho, Seung Hyun; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2008-12-15

Guided wave technology is advantageous for fast inspection of pipe wall thinning since the guided wave propagates long distance. In this investigation, the method to evaluate gradual wall thinning in a pipe based on the arrival time delay with magnetostrictive patch transducers is presented. Low frequency A0 Lamb waves were generated and measured by the present transducer and it was applied to arrival time delay measurement experiments on a test pipe having gradual wall thinnings artificially manufactured. From experiments, consistent results that wall thinning increases the arrival time delay of A0 waves were obtained. Consequently, the feasibility of the magnetostrictive patch transducers to evaluate wall thinning was verified

Pipe Wall Thinning Evaluation through the Arrival Time Delay of A0 Lamb Wave Using Magnetostrictive Patch Transducers

International Nuclear Information System (INIS)

Cho, Seung Hyun; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok

2008-01-01

Guided wave technology is advantageous for fast inspection of pipe wall thinning since the guided wave propagates long distance. In this investigation, the method to evaluate gradual wall thinning in a pipe based on the arrival time delay with magnetostrictive patch transducers is presented. Low frequency A0 Lamb waves were generated and measured by the present transducer and it was applied to arrival time delay measurement experiments on a test pipe having gradual wall thinnings artificially manufactured. From experiments, consistent results that wall thinning increases the arrival time delay of A0 waves were obtained. Consequently, the feasibility of the magnetostrictive patch transducers to evaluate wall thinning was verified

Influences of overload on low cycle fatigue behaviors of elbow pipe with local wall thinning

International Nuclear Information System (INIS)

Sato, Kyohei; Ogino, Kanako; Takahashi, Koji; Ando, Kotoji; Urabe, Yoshio

2011-01-01

Low cycle fatigue tests were conducted using 100A elbow pipe specimens with or without local wall thinning. Local wall thinning was machined on the inside of the extrados of test elbows to simulate metal loss due to flow-accelerated corrosion or liquid droplet impingement erosion. Low cycle fatigue tests were carried out under displacement control with an inner pressure of 9 MPa. To simulate seismic events, low cycle fatigue tests were carried out on elbow pipe subjected to cyclic overloads. Regardless of local wall thinning, fatigue life of overload pipe was not so different from that of the non-overload pipe in appearance. Miner's rule can be applied to evaluate fatigue life of the elbow pipes with and without wall thinning, even if overload is applied. (author)

Local effects in flow-accelerated corrosion wall thinning

International Nuclear Information System (INIS)

Pietralik, J.

2006-01-01

'Full text:' There is enough evidence that flow conditions play the dominant role locally in Flow-Accelerated Corrosion (FAC) under certain conditions, e.g., in CANDU feeders. While chemistry and materials set the overall potential for FAC, which can be low or high, flow conditions determine the local distribution of wall thinning. This relationship is not new and recent accurate measurements of FAC rate of a plant feeder bend confirm that the relationship between flow local conditions expressed by local mass transfer coefficient and FAC rate in CANDU feeder bends is close. There is also a lot of other direct and indirect, experimental and laboratory evidence about this relationship. This knowledge can be useful for minimizing inspection, predicting new locations for inspection, predicting the location with the highest FAC rate for a given piping component, e.g., feeder element, and determining what components or feeders and to what extent they should be replaced. It applies also to heat exchangers and steam generators. The objective of this paper is to examine the relationship between FAC rate and local flow parameters. For FAC, the most important flow parameter is mass transfer coefficient. The mass transfer coefficient describes the intensity of the transport of corrosion products from the oxide-water interface into the bulk water. Therefore, this parameter can be used for predicting the local distribution of FAC rate. It could also be used in planning experiments because time-varying surface roughness can explain the time-dependence of FAC rates. The paper presents plant and laboratory evidence about the relationship. In addition, it shows correlations for mass transfer coefficient in components that are highly susceptible to FAC. The role of surface roughness, wall shear stress, and local turbulence is also discussed. (author)

Method of fabricating thin-walled articles of tungsten-nickel-iron alloy

Science.gov (United States)

Hovis, Jr., Victor M.; Northcutt, Jr., Walter G.

1982-01-01

The present invention relates to a method for fabricating thin-walled high-density structures oftungsten-nickel-iron alloys. A powdered blend of the selected alloy constituents is plasma sprayed onto a mandrel having the desired article configuration. The sprayed deposit is removed from the mandrel and subjected to liquid phase sintering to provide the alloyed structure. The formation of the thin-walled structure by plasma spraying significantly reduces shrinkage, and cracking while increasing physical properties of the structure over that obtainable by employing previously known powder metallurgical procedures.

Development of engineering program for integrity evaluation of pipes with local wall thinned defects

International Nuclear Information System (INIS)

Park, Chi Yong; Lee, Sung Ho; Kim, Tae Ryong; Park, Sang Kyu

2008-01-01

Integrity evaluation of pipes with local wall thinning by erosion and corrosion is increasingly important in maintenance of wall thinned carbon steel pipes in nuclear power plants. Though a few program for integrity assessment of wall thinned pipes have been developed in domestic nuclear field, however those are limited to straight pipes and methodology proposed in ASME Sec.XI Code Case N-597. Recently, the engineering program for integrity evaluation of pipes with all kinds of local wall defects such as straight, elbow, reducer and branch pipes was developed successfully. The program was designated as PiTEP (Pipe Thinning Evaluation Program), which name was registered as a trademark in the Korea Intellectual Property Office. A developed program is carried out by sequential step of four integrity evaluation methodologies, which are composed of construction code, code case N-597, its engineering method and two developed owner evaluation method. As PiTEP program will be performed through GUI (Graphic User Interface) with user's familiarity, it would be conveniently used by plant engineers with only measured thickness data, basic operation conditions and pipe data

Material Behavior Based Hybrid Process for Sheet Draw-Forging Thin Walled Magnesium Alloys

International Nuclear Information System (INIS)

Sheng, Z.Q.; Shivpuri, R.

2005-01-01

Magnesium alloys are conventionally formed at the elevated temperatures. The thermally improved formability is sensitive to the temperature and strain rate. Due to limitations in forming speeds, tooling strength and narrow processing windows, complex thin walled parts cannot be made by traditional warm drawing or hot forging processes. A hybrid process, which is based on the deformation mechanism of magnesium alloys at the elevated temperature, is proposed that combines warm drawing and hot forging modes to produce an aggressive geometry at acceptable forming speed. The process parameters, such as temperatures, forming speeds etc. are determined by the FEM modeling and simulation. Sensitivity analysis under the constraint of forming limits of Mg alloy sheet material and strength of tooling material is carried out. The proposed approach is demonstrated on a conical geometry with thin walls and with bottom features. Results show that designed geometry can be formed in about 8 seconds, this cannot be formed by conventional forging while around 1000s is required for warm drawing. This process is being further investigated through controlled experiments

Graphite nodule count and size distribution in thin-walled ductile cast iron

DEFF Research Database (Denmark)

Pedersen, Karl Martin; Tiedje, Niels Skat

2008-01-01

Graphite nodule count and size distribution have been analysed in thin walled ductile cast iron. The 2D nodule counts have been converted into 3D nodule count by using Finite Difference Method (FDM). Particles having a diameter smaller than 5 µm should be neglected in the nodule count as these ar......Graphite nodule count and size distribution have been analysed in thin walled ductile cast iron. The 2D nodule counts have been converted into 3D nodule count by using Finite Difference Method (FDM). Particles having a diameter smaller than 5 µm should be neglected in the nodule count...... as these are inclusions and micro porosities that do not influence the solidification morphology. If there are many small graphite nodules as in thin walled castings only 3D nodule count calculated by FDM will give reliable results. 2D nodule count and 3D nodule count calculated by simple equations will give too low...

Leakproof Swaged Joints in Thin-Wall Tubing

Science.gov (United States)

Stuckenberg, F. H.; Crockett, L. K.; Snyder, W. E.

1986-01-01

Tubular inserts reinforce joints, reducing incidence of leaks. In new swaging technique, tubular inserts placed inside ends of both tubes to be joined. Made from thicker-wall tubing with outside diameter that matches inside diameter of thin tubing swaged, inserts support tube ends at joint. They ensure more uniform contact between swage fitting and tubing. New swaging technique developed for Al/Ti/V-alloy hydraulic supply lines.

Positioning a thin-wall round wrapper within a heavy wall out-of-round shell of a heat exchanger

International Nuclear Information System (INIS)

Hargrove, H.G.; Thompson, E.G.; Bayless, J.R.

1983-01-01

A thin-wall, generally round wrapper is installed within a heavy wall, rolled heat exchanger shell which has greater out-of-round tolerances than the wrapper and the wrapper is maintained in its round state by utilizing a plurality of jacks disposed adjacent spaced tube support plates within the wrapper. (author)

The thin-walled abnormity measurement technology research based on CCD

International Nuclear Information System (INIS)

Wang Bin

2014-01-01

The character of the thin-walled irregular parts is: the measured parameters for spatial structure size, need to design special measurement positioning fixture to complete detection, the wall thickness is very thin, and the processing is composite, its size is small and shape is complex, it is difficulty to collect image edge by using the optical measurement method. In this paper, a special measurement method of CCD that based on the image measurement technique was advanced, this kind of parts was measured quickly, accurately and automaticly through design the high precision positioning fixture and image acquisition method. At the same time, the comprehensive evaluation standard was given to assess the measurement accuracy method, and the reliability of measurement method was ensured. (author)

Effect of local wall thinning on the collapse behavior of pipe elbows subjected to a combined internal pressure and in-plane bending load

International Nuclear Information System (INIS)

Kim, Jin-Weon; Na, Man-Gyun; Park, Chi-Yong

2008-01-01

The objective of this study was to investigate the effect of local wall thinning on the collapse behavior of pipe elbows subjected to a combined internal pressure and in-plane bending load. This study evaluated the global deformation behavior and collapse moment of the elbows, which contained various types of local wall-thinning defects at their intrados or extrados, using three-dimensional elastic-plastic finite element analysis. The analysis results showed that the global deformation behavior of locally wall-thinned elbows was largely governed by the mode of the bending and the elbow geometry rather than the wall-thinning parameters, except for elbows with considerably large and deep wall thinning that showed plastic instabilities induced by local buckling and plastic collapsing in the thinned area. The reduction in the collapse moment with wall-thinning depth was considerable when local buckling occurred in the thinned areas, whereas the effect of the thinning depth was small when ovalization occurred. The effects of the circumferential thinning angle and thinning length on the collapse moment of elbows were not major for shallow wall-thinning cases. For deeper wall-thinning cases, however, their effects were significant and the dependence of collapse moment on the axial thinning length was governed by the stress type applied to the wall-thinned area. Typically, the reduction in the collapse moment due to local wall thinning was clearer when the thinning defect was located at the intrados rather than the extrados, and it was apparent for elbows with larger bend radius

Deposition Time and Thermal Cycles of Fabricating Thin-wall Steel Parts by Double Electrode GMAW Based Additive Manufacturing

Directory of Open Access Journals (Sweden)

Yang Dongqing

2017-01-01

Full Text Available The deposition time for fabricating the thin-wall part as well as the peak temperature of the substrate during the process was analyzed in the double electrode gas metal arc welding (DE-GMAW based additive manufacturing (AM. The total deposition time and the interlayer idle time of the manufacturing process decreased with the increasing of the bypass current under the same interlayer temperature and the same deposition rate. The thermal cycling curves illustrated that the peak temperature of the substrate was lower in the DE-GMAW base AM under the same conditions. When depositing the thin-wall parts, the DE-GMAW based AM can reduce the heat input to the substrate and improve the fabrication efficiency, compared with the GMAW based AM.

A new local thickening reverse spiral origami thin-wall construction for improving of energy absorption

Science.gov (United States)

Kong, C. H.; Zhao, X. L.; Hagiwara, I. R.

2018-02-01

As an effective and representative origami structure, reverse spiral origami structure can be capable to effectively take up energy in a crash test. The origami structure has origami creases thus this can guide the deformation of structure and avoid of Euler buckling. Even so the origami creases also weaken the support force and this may cut the absorption of crash energy. In order to increase the supporting capacity of the reverse spiral origami structure, we projected a new local thickening reverse spiral origami thin-wall construction. The reverse spiral origami thin-wall structure with thickening areas distributed along the longitudinal origami crease has a higher energy absorption capacity than the ordinary reverse spiral origami thin-wall structure.

Vibrational behavior of adaptive aircraft wing structures modelled as composite thin-walled beams

Science.gov (United States)

Song, O.; Librescu, L.; Rogers, C. A.

1992-01-01

The vibrational behavior of cantilevered aircraft wings modeled as thin-walled beams and incorporating piezoelectric effects is studied. Based on the converse piezoelectric effect, the system of piezoelectric actuators conveniently located on the wing yield the control of its associated vertical and lateral bending eigenfrequencies. The possibility revealed by this study enabling one to increase adaptively the eigenfrequencies of thin-walled cantilevered beams could play a significant role in the control of the dynamic response and flutter of wing and rotor blade structures.

Iron melt flow in thin-walled sections using vertically parted moulds

DEFF Research Database (Denmark)

Larsen, Per; Tiedje, Niels

2004-01-01

gating systems are used small changes in the casting conditions can change the flow patterns radically. Flow in thin walled sections is not only important in thin walled part. This is illustrated with a brake disc as example. 3 different layouts have been made. The filling sequences have been recorded...... sizes of the dynamic and braking forces in the gating system.......Reducing the fuel consumption of vehicles can be done in many ways. A general way of doing it, is to reduce the weight as it is applicable together with all other means of saving fuel. Even though iron castings have been used in cars from the first car ever build, a big potential still exist...

Development of wall thinning screening system and its application to a commercial nuclear power plant

International Nuclear Information System (INIS)

Ryu, Kyung Ha; Hwang, Il Soon; Kim, Ji Hyun

2013-01-01

Highlights: • Wall loss screening system (WalSS) has been developed based on ES-DCPD method. • Screening criteria was established based on the thinning of the actual shape that occur in the power plant. • With the criteria, the WalSS gives priority of the need for inspection. • This technique was successfully applied to commercial nuclear power plant. - Abstract: A new non-destructive evaluation (NDE) method has been developed for metal pipes for the detection wall thinning. The method has been showed to be suitable for applications to electric power generation plants where flow accelerated corrosion (FAC) of carbon steel piping is a significant cause of increased maintenance and plant personnel casualty. The wall thinning screening system (WalSS) was developed in two major phases. In the first phase, the equipotential switching direct current potential drop (ES-DCPD) method was developed for piping wall (Ryu et al., 2008a, 2010). In the second phase, in this paper, a quantitative detection criteria was developed. The relative ES-DCPD change of 3.8% has been defined as the screening criteria for wall thinning schematization. This criteria means that the component with measured ES-DCPD change greater than 3.8% is called for a more comprehensive examination. In the criteria development, all variables were taken into consideration based on commercial plant piping inspection data such as initial thickness distributions, wall thinning shape and nominal thickness. The developed WalSS based on ES-DCPD was applied to a moisture separator reheater (MSR) drain line of a commercial nuclear power plant (NPP) during a scheduled overhaul. The measured ES-DCPD change was 2.16%, which is lower than the ES-DCPD criteria, identifying the pipe having adequate wall thickness. This is confirmed by site thickness inspection using ultrasonic technique (UT)

Buckling of thin-walled beams under concentrated transverse loading

NARCIS (Netherlands)

Menken, C.M.; Erp, van G.M.; Krupta, V.; Drdacky, M.

1991-01-01

The transversely loaded thin-walled beam under a non-uniform bending moment forms an example of the detrimental influence that a local effect may have on the overall behaviour. The local effect is the plate buckling in the region of maximum bending moment. The overall behaviour is the

Evaluation of flow accelerated corrosion by coupled analysis of corrosion and flow dynamics (1), major features of coupled analysis and application for evaluation of wall thinning rate

International Nuclear Information System (INIS)

Naitoh, Masanori; Uchida, Shunsuke; Okada, Hidetoshi; Uehara, Yasushi; Koshizuka, Seiichi

2009-01-01

Six calculation steps have been prepared for predicting flow accelerated corrosion (FAC) occurrence and evaluating wall thinning rate. (1) Flow pattern and temperature in each elemental volume along the flow path are obtained with a 1D plant system code, (2) Corrosive conditions, e.g., oxygen concentration and electrochemical corrosion potential (ECP) along the flow path are calculated with a hydrazine-oxygen reaction code, (3) Precise flow patterns and mass transfer coefficients at the structure surface are calculated with a 3D CFD code, (4) Danger zones are evaluated by combining major FAC parameters, (5) Wall thinning rates are calculated with the coupled models of static electrochemical analysis and dynamic double oxide layer analysis at the identified danger zone, and then, (6) Residual life and effects of countermeasures can be evaluated. Anodic and cathodic current densities and ECPs were calculated with the static electrochemistry model, and ferrous ion release rate determined by the anodic current density was used as input for the dynamic double oxide layer model. Thickness of the oxide film and its characteristics determined by the dynamic double oxide layer model were used for the electrochemistry model to determine the resistances of cathodic current from the bulk to the surface and anodic current from the surface to the bulk. The calculated results of the coupled models had been compared with the data measured at operating Boiling Water Reactor (BWR) plants and it was demonstrated that the calculated results had good agreements with the measured ones. 6 step-evaluation procedures for liquid droplet impingement (LDI) were also proposed. (author)

Atomic layer deposition of copper thin film and feasibility of deposition on inner walls of waveguides

Science.gov (United States)

Yuqing, XIONG; Hengjiao, GAO; Ni, REN; Zhongwei, LIU

2018-03-01

Copper thin films were deposited by plasma-enhanced atomic layer deposition at low temperature, using copper(I)-N,N‧-di-sec-butylacetamidinate as a precursor and hydrogen as a reductive gas. The influence of temperature, plasma power, mode of plasma, and pulse time, on the deposition rate of copper thin film, the purity of the film and the step coverage were studied. The feasibility of copper film deposition on the inner wall of a carbon fibre reinforced plastic waveguide with high aspect ratio was also studied. The morphology and composition of the thin film were studied by atomic force microscopy and x-ray photoelectron spectroscopy, respectively. The square resistance of the thin film was also tested by a four-probe technique. On the basis of on-line diagnosis, a growth mechanism of copper thin film was put forward, and it was considered that surface functional group played an important role in the process of nucleation and in determining the properties of thin films. A high density of plasma and high free-radical content were helpful for the deposition of copper thin films.

Evaluation of wall thinning of piping with reinforcing plates using ECT with controlled exciting field

International Nuclear Information System (INIS)

Ichihara, Toshiaki; Xie, Shejuan; Uchimoto, Tetsuya; Takagi, Toshiyuki

2011-01-01

No effective inspection method exists at present for detection and evaluation of wall thinning under the reinforcing plates to T-tubes in nuclear power plants, and the establishment of the inspection method is highly required. In this study, eddy current testing (ECT) with controlled exciting field is applied to evaluation of wall thinning under the reinforcing plates of T-tubes, and their feasibility is discussed. In order to induce eddy current field in deep region of doubled plates, pulse excitation and probe structures are investigated. Through experiments using specimens simulating tubes with reinforcing plates, it is shown that pulsed ECT and conventional TR type eddy current probe with optimized configuration have a capability of detecting and sizing the wall thinning under reinforcing plates. (author)

A study on optimization of laser-generated ultrasound for evaluation of wall-thinning in pipelines

International Nuclear Information System (INIS)

Kang, Seung Hyun; Lee, Joon Hyun; Cho, Youn Ho

2004-01-01

Carbon steel pipes of nuclear power plants, local wall thinning may result from erosion-corrosion or FAC(Flow Accelerated Corrosion) damage. Local wall thinning is one of the major causes for the structural fracture of these pipes. Therefore, assessment of local wall thinning due to corrosion is an important issue in nondestructive evaluation for the integrity of nuclear power plants. In this study, a pulsed laser with an linear array slit generated guided waves in a carbon steel pipe. Time-frequency analysis of ultrasonic waveforms using the wavelet transform allowed the identification of generated guided wave modes by comparison with the theoretical dispersion curves. This study shows some experimental results about optimization of generating laser ultrasound using various linear array slits.

A thin-walled pressurized sphere exposed to external general corrosion and nonuniform heating

Science.gov (United States)

Sedova, Olga S.; Pronina, Yulia G.; Kuchin, Nikolai L.

2018-05-01

A thin-walled spherical shell subjected to simultaneous action of internal and external pressure, nonuniform heating and outside mechanochemical corrosion is considered. It is assumed that the shell is homogeneous, isotropic and linearly elastic. The rate of corrosion is linearly dependent on the equivalent stress, which is the sum of mechanical and temperature stress components. Paper presents a new analytical solution, which takes into account the effect of the internal and external pressure values themselves, not only their difference. At the same time, the new solution has a rather simple form as compared to the results based on the solution to the Lame problem for a thick-walled sphere under pressure. The solution obtained can serve as a benchmark for numerical analysis and for a qualitative forecast of durability of the vessel.

A Study on Effect of Local Wall Thinning in Carbon Steel Elbow Pipe on Elastic Stress Concentration

International Nuclear Information System (INIS)

Kim, Jong Sung; Seo, Jae Seok

2009-01-01

Feeder pipes that connect the inlet and outlet headers to the reactor core in CANDU nuclear power plants are considered as safety Class 1 piping items. Therefore, fatigue of feeder pipes should be assessed at design stage in order to verify structural integrity during design lifetime. In accordance with the fatigue assessment result, cumulative usage factors of some feeder pipes have significant values. The feeder pipes made of SA-106 Grade B or C carbon steel have some elbows and bends. An active degradation mechanism for the carbon steel outlet feeder piping is local wall thinning due to flow-accelerated corrosion. Inspection results from plants and metallurgical examinations of removed feeders indicated the presence of localized thinning in the vicinity of the welds in the lower portion of outlet feeders, such as Grayloc hub-to-bend weld, Grayloc hub-to-elbow weld, elbow-to-elbow, and elbow-to-pipe weld. This local wall thinning can cause increase of peak stress due to stress concentration by notch effect. The increase of peak stress results in increase of cumulative usage factor. However, present fatigue assessment doesn't consider the stress concentration due to local wall-thinning. Therefore, it is necessary to assess the effect of local wall thinning on stress concentration. This study investigates the effect of local wall thinning geometry on stress concentration by performing finite element elastic stress analysis

Numerical modelling of thin-walled hypereutectic ductile cast iron parts

DEFF Research Database (Denmark)

Pedersen, Karl Martin; Hattel, Jesper Henri; Tiedje, Niels Skat

2006-01-01

Solidification of hypereutectic thin-walled ductile cast iron has been modelled in one dimension taking into account the precipitation of off-eutectic austenite dendrites during solidification. The simulations have been compared with casting experiments on plate geometries with plate thicknesses...

Mass transfer effects in feeder flow-accelerated corrosion wall thinning

International Nuclear Information System (INIS)

Pietralik, J.

2008-01-01

Flow conditions play a dominant role in Flow-Accelerated Corrosion (FAC) under certain conditions, e.g., in CANDU feeders. While chemistry and materials set the overall potential for FAC, flow conditions determine the local distribution of wall thinning. Recent plant data of feeders and laboratory tests confirms that there is a close relationship between local flow conditions, expressed by mass transfer coefficient, and FAC rate in CANDU feeder bends. The knowledge of local effects can be useful for minimizing the number of inspected components, predicting the location of the highest FAC rate for a given piping component, and determining what components or feeders should be replaced. A similar evaluation applies also to FAC in heat transfer equipment such as heat exchangers and steam generators. The objective of this paper is to examine the relationship between FAC rate and local mass transfer parameters. For FAC where the flow is dominant, the FAC rate is proportional to mass flux of ferrous ions. The mass flux is the product of the mass transfer coefficient and the concentration difference, or degree of saturation. The mass transfer coefficient describes the intensity of the transport of corrosion products (ferrous ions) from the oxide-water interface into the bulk water. Therefore, this parameter can be used for predicting the local distribution of FAC rate in the mass-transfer controlled FAC. The degree of saturation reduces the mass flux, thus reducing the FAC rate. This effect can be significant in long piping, e.g., in outlet feeders. The paper presents plant and laboratory evidence for the relationship between local mass transfer conditions and the FAC rate. It shows correlations for mass transfer coefficient in components that are highly susceptible to FAC and most important flow parameters that affect mass transfer coefficient. The role of surface roughness, wall shear stress, and local turbulence is also discussed. (author)

New technical knowledge to be implemented to the revision of rules on pipe wall thinning management for PWR plants

International Nuclear Information System (INIS)

Hirai, Junya; Nakamura, Takao; Amano, Yoichi

2013-01-01

Rules for PWR plant pipe wall thinning management were formulated by the Japan Society of Mechanical Engineers in 2006. Since then thinning management of Japanese PWR plants has been carried out based on this rule. Pipe wall thinning phenomena to be dealt with in this rule have been identified in many piping components of power plants. New technical knowledge has been accumulated since the issuance of 2006 edition. We have formulated these knowledge and information about the thinning phenomena in PWR power plants. Given the history of application of this rule, we have to make our best effort to carry out a study of latest technical knowledge and implement them to the revision of rule and improve pipe wall thinning management. This paper summarizes the new technical knowledge and basis to be implemented to the revision of rules on pipe wall thinning management for PWR plants in Japan. (author)

Detection of wall thinning of carbon steel pipe covered with insulation using Pulsed Eddy Current technique

International Nuclear Information System (INIS)

Park, Duckgun; Kishore, M. B.; Lee, D. H.

2013-01-01

The test sample is a ferromagnetic carbon steel pipe having different thickness, covered with a 10 cm plastic insulation laminated by 0.4 mm Al plate to simulate the pipelines in NPPs. The PEC Probe used for the wall thinning detection consists of an excitation coil and a Hall sensor. The excitation coils in the probe is driven by a rectangular bipolar current pulse and the Hall-sensor will detects the resultant field. The Hall sensor output is considered as PEC signal. Results shows that the PEC system can detect wall thinning in an insulated pipeline of the NPPs. Local wall thinning in pipelines affects the structural integrity of industries like nuclear power plants (NPPs). In the present study a pulsed eddy current (PEC) technology to detect the wall thing of carbon steel pipe covered with insulation is developed

Numerical study on injection parameters optimization of thin wall and biodegradable polymers parts

Science.gov (United States)

Santos, C.; Mendes, A.; Carreira, P.; Mateus, A.; Malça, C.

2017-07-01

Nowadays, the molds industry searches new markets, with diversified and added value products. The concept associated to the production of thin walled and biodegradable parts mostly manufactured by injection process has assumed a relevant importance due to environmental and economic factors. The growth of a global consciousness about the harmful effects of the conventional polymers in our life quality associated with the legislation imposed, become key factors for the choice of a particular product by the consumer. The target of this work is to provide an integrated solution for the injection of parts with thin walls and manufactured using biodegradable materials. This integrated solution includes the design and manufacture processes of the mold as well as to find the optimum values for the injection parameters in order to become the process effective and competitive. For this, the Moldflow software was used. It was demonstrated that this computational tool provides an effective responsiveness and it can constitute an important tool in supporting the injection molding of thin-walled and biodegradable parts.

Stabilization of thin shell modes by a rotating secondary wall

International Nuclear Information System (INIS)

Gimblett, C.G.

1989-01-01

A simple model is developed to investigate if and under what circumstances the thin shell instabilities of a Reverse Field Pinch can be stabilized by a rotating secondary wall. The principles may be applicable to reactor designs that utilize a flowing liquid blanket (author)

Manufacturing of thin walled near net shape iron castings

DEFF Research Database (Denmark)

Larsen, Per Leif

2003-01-01

The demand for near net shape thin walled iron castings is growing. This has several reasons, the main one is the need for lowering the fuel consumption of cars; the easiest way to do that is to lower the weight of the cars. The best way to do this was for a period of time believed...

Nonlinear analysis of composite thin-walled helicopter blades

Science.gov (United States)

Kalfon, J. P.; Rand, O.

Nonlinear theoretical modeling of laminated thin-walled composite helicopter rotor blades is presented. The derivation is based on nonlinear geometry with a detailed treatment of the body loads in the axial direction which are induced by the rotation. While the in-plane warping is neglected, a three-dimensional generic out-of-plane warping distribution is included. The formulation may also handle varying thicknesses and mass distribution along the cross-sectional walls. The problem is solved by successive iterations in which a system of equations is constructed and solved for each cross-section. In this method, the differential equations in the spanwise directions are formulated and solved using a finite-differences scheme which allows simple adaptation of the spanwise discretization mesh during iterations.

Evaluation of stresses in large diameter, thin walled piping at support locations

International Nuclear Information System (INIS)

Bryan, B.J.; Flanders, H.E. Jr.; Rawls, G.B. Jr.

1992-01-01

The highest stresses in many thin walled piping systems are the local stresses at the pipe supports. These secondary stresses are caused by saddles or other structural discontinuities that restrain pipe ovalization. A static analysis of a thin walled pipe supported on structural steel saddle under dead weight loading is presented. The finite element analysis is performed using a shell model with distributed gravity and hydrostatic pressure loading. Parametric studies on global and local stress are performed to determine the effect of the pipe diameter to thickness ratio. Two aspects of the saddle design are also investigated: the effect of saddle width, and the effect of saddle wrap angle. Additionally, the computed stresses are compared to closed form solutions

Thin-walled large-diameter zirconium alloy tubes in CANDU reactors

International Nuclear Information System (INIS)

Price, E.G.; Richinson, P.J.

1978-08-01

The requirements of the thin-walled large-diameter Zircaloy-2 tubing used in CANDU reactors are reviewed. Strength, residual stress patterns, texture and prior deformation contribute to the stability of these tubes. The extent to which the present manufacturing route meets these requirements is discussed. (author)

Skin effect modifications of the Resistive Wall Mode dynamics in tokamaks

Energy Technology Data Exchange (ETDEWEB)

Villone, Fabio, E-mail: villone@unicas.it [Ass. Euratom/ENEA/CREATE, DIEI, Università di Cassino e del Lazio Meridionale, Via Di Biasio 43, 03043 Cassino, FR (Italy); Pustovitov, Vladimir D. [Institute of Tokamak Physics, National Research Centre ‘Kurchatov Institute’, Pl. Kurchatova 1, Moscow 123182 (Russian Federation)

2013-11-22

We present the first evidence of the skin-effect modification of the Resistive Wall Mode (RWM) dynamics in a tokamak. The computations are performed with the CarMa code, using its unique ability of treating volumetric 3D conducting structures. The results prove that conventional thin-wall models and codes, assuming the thin equivalent wall located on the inner side of a real (thick) wall, may fail to get accurate estimates of RWM growth rates, since the inclusion of the skin effect makes the growth rates always larger than otherwise. The difference is noticeable even for the conventional slow RWMs and becomes substantial for faster modes. Some possible equivalent thin-wall modeling approaches are also discussed.

ON-POWER DETECTION OF PIPE WALL-THINNED DEFECTS USING IR THERMOGRAPHY IN NPPS

Directory of Open Access Journals (Sweden)

JU HYUN KIM

2014-04-01

Full Text Available Wall-thinned defects caused by accelerated corrosion due to fluid flow in the inner pipe appear in many structures of the secondary systems in nuclear power plants (NPPs and are a major factor in degrading the integrity of pipes. Wall-thinned defects need to be managed not only when the NPP is under maintenance but also when the NPP is in normal operation. To this end, a test technique was developed in this study to detect such wall-thinned defects based on the temperature difference on the surface of a hot pipe using infrared (IR thermography and a cooling device. Finite element analysis (FEA was conducted to examine the tendency and experimental conditions for the cooling experiment. Based on the FEA results, the equipment was configured before the cooling experiment was conducted. The IR camera was then used to detect defects in the inner pipe of the pipe specimen that had artificially induced defects. The IR thermography developed in this study is expected to help resolve the issues related to the limitations of non-destructive inspection techniques that are currently conducted for NPP secondary systems and is expected to be very useful on the NPPs site.

Investigation into the influence of laser energy input on selective laser melted thin-walled parts by response surface method

Science.gov (United States)

Liu, Yang; Zhang, Jian; Pang, Zhicong; Wu, Weihui

2018-04-01

Selective laser melting (SLM) provides a feasible way for manufacturing of complex thin-walled parts directly, however, the energy input during SLM process, namely derived from the laser power, scanning speed, layer thickness and scanning space, etc. has great influence on the thin wall's qualities. The aim of this work is to relate the thin wall's parameters (responses), namely track width, surface roughness and hardness to the process parameters considered in this research (laser power, scanning speed and layer thickness) and to find out the optimal manufacturing conditions. Design of experiment (DoE) was used by implementing composite central design to achieve better manufacturing qualities. Mathematical models derived from the statistical analysis were used to establish the relationships between the process parameters and the responses. Also, the effects of process parameters on each response were determined. Then, a numerical optimization was performed to find out the optimal process set at which the quality features are at their desired values. Based on this study, the relationship between process parameters and SLMed thin-walled structure was revealed and thus, the corresponding optimal process parameters can be used to manufactured thin-walled parts with high quality.

Impact effects in thin-walled structures

International Nuclear Information System (INIS)

Zukas, J.A.; Gaskill, B.

1996-01-01

A key parameter in the design of protective structures is the critical impact velocity, also known as the ballistic limit. This is the velocity below which a striker will fail to penetrate a barrier or some protective device. For strikers with regular shapes, such as cylinders (long and short), spheres and cones, analytical and empirical formulations for the determination of a ballistic limit exist at impact velocities ranging from 250 m/s to 6 km/s or higher. For non-standard shapes, two- and three-dimensional wave propagation codes (hydrocodes) can be valuable adjuncts to experiments in ballistic limit determinations. This is illustrated with the help of the ZeuS code in determining the ballistic limit of a short, tubular projectile striking a thin aluminum barrier and contrasting it to the value of the ballistic limit of a spherical projectile of equal mass against the same target. Several interesting features of the debris cloud generated by a tubular projectile striking a Whipple shield at hypervelocity are also pointed out. The paper concludes with a consideration of hydrodynamic ram effects in fluid-filled thin-walled structures. Where possible, comparisons are made of computed results with experimental data

New technical knowledge to be implemented to the revision of rules on pipe wall thinning management for PWR Plants. 2006 edition

International Nuclear Information System (INIS)

Hirai, Junya; Amano, Yoichi; Nakamura, Takao

2013-01-01

Rules for PWR plant pipe wall thinning management were formulated by the Japan Society of Mechanical Engineers in 2006. Since then thinning management of Japanese PWR plants has been carried out based on this rule. Pipe wall thinning phenomena to be dealt with in this rule have been identified in many piping components of power plants. New technical knowledge has been accumulated since the issuance of 2006 edition. We have formulated these knowledge and information about the thinning phenomena in PWR power plants. Given the history of application of this rule, we have to make our best effort to carry out a study of latest technical knowledge and implement them to the revision of rule and improve pipe wall thinning management. This paper summarizes the new technical knowledge and basis to be implemented to the revision of rules on pipe wall thinning management for PWR plants in Japan. (author)

Experimental validation of tape springs to be used as thin-walled space structures

Science.gov (United States)

Oberst, S.; Tuttle, S. L.; Griffin, D.; Lambert, A.; Boyce, R. R.

2018-04-01

With the advent of standardised launch geometries and off-the-shelf payloads, space programs utilising nano-satellite platforms are growing worldwide. Thin-walled, flexible and self-deployable structures are commonly used for antennae, instrument booms or solar panels owing to their lightweight, ideal packaging characteristics and near zero energy consumption. However their behaviour in space, in particular in Low Earth Orbits with continually changing environmental conditions, raises many questions. Accurate numerical models, which are often not available due to the difficulty of experimental testing under 1g-conditions, are needed to answer these questions. In this study, we present on-earth experimental validations, as a starting point to study the response of a tape spring as a representative of thin-walled flexible structures under static and vibrational loading. Material parameters of tape springs in a singly (straight, open cylinder) and a doubly curved design, are compared to each other by combining finite element calculations, with experimental laser vibrometry within a single and multi-stage model updating approach. While the determination of the Young's modulus is unproblematic, the damping is found to be inversely proportional to deployment length. With updated material properties the buckling instability margin is calculated using different slenderness ratios. Results indicate a high sensitivity of thin-walled structures to miniscule perturbations, which makes proper experimental testing a key requirement for stability prediction on thin-elastic space structures. The doubly curved tape spring provides closer agreement with experimental results than a straight tape spring design.

Humidity Sensor Based on Multi-Walled Carbon Nanotube Thin Films

International Nuclear Information System (INIS)

Cao, C.L.; Hu, C.G.; Fang, L.; Wang, S.X.; Cao, C.L.; Tian, Y.S.; Pan, C.Y.

2009-01-01

The properties of the humidity sensors made of chemically treated and untreated multi-walled carbon nano tube (MWCNT) thin films are investigated systematically. It shows that both the chemically treated and untreated MWCNT thin films demonstrate humidity sensitive properties, but the former have stronger sensitivity than the latter. In the range of 11%-98% relative humidity (RH), the resistances of the chemically treated and untreated MWCNT humidity sensors increase 120% and 28%, respectively. Moreover, the treated humidity sensors showed higher sensitivity and better stability. In addition, the response and recover properties, and stabilization of the humidity sensors are measured, and the humidity sensitive mechanisms of the sensors are analyzed. The humidity sensitivity of carbon nano tube thin films indicates it promise as a kind of humidity sensitive material

Vibration improved the fluidity of aluminum alloys in thin wall ...

African Journals Online (AJOL)

Misrun is a term used to describe the incomplete filling of the mould cavity. It is a major defect in the investment casting process when used to produce turbine blades, impellers and impulse blades for turbo pumps which have complex profiles, thin walls and sharp edges. From the casting engineering point of view, poor ...

Development of a Thin-Wall Magnesium side door Inner Panel for Automobiles

Energy Technology Data Exchange (ETDEWEB)

Jekl, J.; Auld, J.; Sweet, C.; Carter, Jon; Resch, Steve; Klarner, A.; Brevick, J.; Luo, A.

2015-05-17

Cast magnesium side door inner panels can provide a good combination of weight, functional, manufacturing and economical requirements. However, several challenges exist including casting technology for thin-wall part design, multi-material incompatibility and relatively low strength vs steel. A project has been initiated, supported by the US Department of Energy, to design and develop a lightweight frame-under-glass door having a thin-wall, full die-cast, magnesium inner panel. This development project is the first of its kind within North America. Phase I of the project is now complete and the 2.0mm magnesium design, through casting process enablers, has met or exceeded all stiffness requirements, with significant mass reduction and part consolidation. In addition, a corrosion mitigation strategy has been established using industry-accepted galvanic isolation methods and coating technologies.

Thinned pipe management program of Korean NPPs

International Nuclear Information System (INIS)

Lee, S.H.; Kim, T.R.; Jeon, S.C.; Hwang, K.M.

2003-01-01

Wall thinning of carbon steel pipe components due to Flow-Accelerated Corrosion (FAC) is one of the most serious threats to the integrity of steam cycle systems in Nuclear Power Plants (NPP). If the thickness of a pipe component is reduced below the critical level, it cannot sustain stress and consequently results in leakage or rupture. In order to minimize the possibility of excessive wall thinning, Thinned Pipe Management Program (TPMP) has been set up and being implemented to all Korean NPPs. Important elements of the TPMP include the prediction of the FAC rate for each component based on model analysis, prioritization of pipe components for inspection, thickness measurement, calculation of wear and wear rate for each component. Additionally, decision making associated with replacement or continuous service for thinned pipe components and establishment of long-term strategic management plan based on diagnosis of plant condition regarding overall wall thinning also are essential part of the TPMP. From pre-service inspection data, it has been found that initial thickness is varies, which influences wear and wear rate calculations. (author)

A Study On Critical Thinning In Thin-walled Tube Bending Of Al-Alloy 5052O Via Coupled Ductile Fracture Criteria

International Nuclear Information System (INIS)

Li Heng; Yang He; Zhan Mei

2010-01-01

Thin-walled tube bending(TWTB) method of Al-alloy tube has attracted wide applications in aerospace, aviation and automobile,etc. While, under in-plane double tensile stress states at the extrados of bending tube, the over-thinning induced ductile fracture is one dominant defect in Al-alloy tube bending. The main objective of this study is to predict the critical wall-thinning of Al-alloy tube bending by coupling two ductile fracture criteria(DFCs) into FE simulation. The DFCs include Continuum Damage Mechanics(CDM)-based model and GTN porous model. Through the uniaxial tensile test of the curved specimen, the basic material properties of the Al-alloy 5052O tube is obtained; via the inverse problem solution, the damage parameters of both the two fracture criteria are interatively determined. Thus the application study of the above DFCs in the TWTB is performed, and the more reasonable one is selected to obtain the critical thinning of Al-alloy tube in bending. The virtual damage initiation and evolution (when and where the ductile fracture occurs) in TWTB are investigated, and the fracture mechanisms of the voided Al-alloy tube in tube bending are consequently discussed.

Elastic torsional buckling of thin-walled composite cylinders

Science.gov (United States)

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.

Numerical modelling of solidification of thin walled hypereutectic ductile cast iron

DEFF Research Database (Denmark)

Pedersen, Karl Martin; Hattel, Jesper; Tiedje, Niels

2006-01-01

Numerical simulation of solidification of ductile cast iron is normally based on a model where graphite nodules are surrounded by an austenite shell. The two phases are then growing as two concentric spheres governed by diffusion of carbon through the austenite shell. Experiments have however shown...... simulation of thin-walled ductile iron castings. Simulations have been performed with a 1-D numerical solidi¬fication model that includes the precipitation of non-eutectic austenite during the eutectic stage. Results from the simulations have been compared with experimental castings with wall thick...

Collapse moment estimation by support vector machines for wall-thinned pipe bends and elbows

International Nuclear Information System (INIS)

Na, Man Gyun; Kim, Jin Weon; Hwang, In Joon

2007-01-01

The collapse moment due to wall-thinned defects is estimated through support vector machines with parameters optimized by a genetic algorithm. The support vector regression models are developed and applied to numerical data obtained from the finite element analysis for wall-thinned defects in piping systems. The support vector regression models are optimized by using both the data sets (training data and optimization data) prepared for training and optimization, and its performance verification is performed by using another data set (test data) different from the training data and the optimization data. In this work, three support vector regression models are developed, respectively, for three data sets divided into the three classes of extrados, intrados, and crown defects, which is because they have different characteristics. The relative root mean square (RMS) errors of the estimated collapse moment are 0.2333% for the training data, 0.5229% for the optimization data and 0.5011% for the test data. It is known from this result that the support vector regression models are sufficiently accurate to be used in the integrity evaluation of wall-thinned pipe bends and elbows

Probabilistic methods for evaluation of erosion-corrosion wall thinning in french pressurized water reactors

International Nuclear Information System (INIS)

Ardillon, E.; Bouchacourt, M.

1994-04-01

This paper describes the application of the probabilistic approach to a selected study section having known characteristics. The method is based on the physico-chemical model of erosion-corrosion, the variables of which are probabilized. The three main aspects of the model, namely the thermohydraulic flow conditions, the chemistry of the fluid, and the geometry of the installation, are described. The study ultimately makes it possible determine: - the evolution of wall thinning distribution, using the power station's measurements; - the main parameters of influence on the kinetics of wall thinning; - the evolution of the fracture probabilistic of the pipe in question. (authors). 10 figs., 7 refs

Assessment of the Manufacturing Possibility of Thin-Walled Robotic Portals for Conveyor Worklace

Directory of Open Access Journals (Sweden)

Peter Michalik

2018-03-01

Full Text Available The paper discusses evaluation of machining solutions for oversized thin-walled robotic portal component for conveyance workplaces. The following portal CNC machining centers have been selected. Firstly, a FSGC 300 “portal type” portal was proposed, with a 50000 mm “X” axis and Heidenhain control system, the second portal was a DMU 340 portal with the maximum axis “X” of 6000 mm and Siemens Sinumerik control system and the last portal was the VF-10 / 40 one, with the maximum axis “X” of 3048 mm and Fanuc control system. Further, the method of fixing a thin-walled robotic portal is designed and individual options are evaluated for their economy. The CAM software application used for programming the production was SolidWorks.

Nucleation and solidification of thin walled ductile iron - Experiments and numerical simulation

DEFF Research Database (Denmark)

Pedersen, Karl Martin; Tiedje, Niels Skat

2005-01-01

Investigation of solidification of thin walled ductile cast iron has been performed based on experiments and numerical simulation. The experiments were based on temperature and microstructure examination. Results of the experiments have been compared with a 1-D numerical solidification model...

Characterization of non-calcareous 'thin' red clay from south-eastern Brazil: applicability in wall tile manufacture

Energy Technology Data Exchange (ETDEWEB)

Sousa, S. J.G.; Holanda, J. N.F., [Grupo de Materiais Ceramicos - LAMAV-CCT, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ (Brazil)

2012-04-15

In this work the use of 'thin' red clay from south-eastern Brazil (Campos dos Goytacazes, RJ) as raw material for the manufacture of wall tile was investigated. A wide range of characterization techniques was employed, including X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), grain-size analysis, and thermogravimetric analysis. The wall tile body was prepared by the dry process. The tile pieces were uniaxially pressed and fired between 1080 - 1180 deg C using a fast-firing cycle. The following technological properties were determined: linear shrinkage, water absorption, apparent density, and flexural strength. The development of the microstructure was followed by SEM and XRD analyses. It was found that the 'thin' red clay is kaolinitic type containing a substantial amount of quartz. The results also showed that the 'thin' red clay could be used in the manufacture of wall tiles, as they present properties compatible with those specified for class BIII of ISO 13006 standard. (author)

Distortional Modes of Thin-Walled Beams

DEFF Research Database (Denmark)

Jönsson, Jeppe; Andreassen, Michael Joachim

2009-01-01

The classic thin-walled beam theory for open and closed cross-sections can be generalized by including distortional displacement modes. The introduction of additional displacement modes leads to coupled differential equations, which seems to have prohibited the use of exact shape functions...... in the modelling of coupled torsion and distortion. However, if the distortional displacement modes are chosen as those which decouple the differential equations as in non proportionally damped modal dynamic analysis then it may be possible to use exact shape functions and perform analysis on a reduced problem....... In the recently developed generalized beam theory (GBT) the natural distortional displacement modes are determined on the basis of a quadratic eigenvalue problem. However, as in linear modal dynamic analysis of proportionally damped structures this problem has been solved approximately using linear eigenvalue...

Behavior of thin-walled beams made of advanced composite materials and incorporating non-classical effects

Science.gov (United States)

Librescu, Liviu; Song, Ohseop

1991-11-01

Several results concerning the refined theory of thin-walled beams of arbitrary closed cross-section incorporating nonclassical effects are presented. These effects are related both with the exotic properties characterizing the advanced composite material structures and the nonuniform torsional model. A special case of the general equations is used to study several problems of cantilevered thin-walled beams and to assess the influence of the incorporated effects. The results presented in this paper could be useful toward a more rational design of aeronautical or aerospace constructions, as well as of helicopter or tilt rotor blades constructed of advanced composite materials.

Temperature measurement during solidification of thin wall ductile cast iron. Part 1: Theory and experiment

DEFF Research Database (Denmark)

Pedersen, Karl Martin; Tiedje, Niels Skat

2008-01-01

cooing curves in thin wall ductile iron castings. The experiments show how TC’s of different design interact with the melt and how TC design and surface quality affect the results of the data acquisition. It is discussed which precautions should be taken to ensure reliable acquisition of cooling curves....... Measurement error depending on TC design and cooling conditions is shown. A method is presented that allows acquisition of cooling curves in thin walled ductile iron castings down to thickness of at least 2.8 mm. The obtained cooling curves can be used to compare nucleation and growth during solidification...

A comparison RSM and ANN surface roughness models in thin-wall machining of Ti6Al4V using vegetable oils under MQL-condition

Science.gov (United States)

Mohruni, Amrifan Saladin; Yanis, Muhammad; Sharif, Safian; Yani, Irsyadi; Yuliwati, Erna; Ismail, Ahmad Fauzi; Shayfull, Zamree

2017-09-01

Thin-wall components as usually applied in the structural parts of aeronautical industry require significant challenges in machining. Unacceptable surface roughness can occur during machining of thin-wall. Titanium product such Ti6Al4V is mostly applied to get the appropriate surface texture in thin wall designed requirements. In this study, the comparison of the accuracy between Response Surface Methodology (RSM) and Artificial Neural Networks (ANN) in the prediction of surface roughness was conducted. Furthermore, the machining tests were carried out under Minimum Quantity Lubrication (MQL) using AlCrN-coated carbide tools. The use of Coconut oil as cutting fluids was also chosen in order to evaluate its performance when involved in end milling. This selection of cutting fluids is based on the better performance of oxidative stability than that of other vegetable based cutting fluids. The cutting speed, feed rate, radial and axial depth of cut were used as independent variables, while surface roughness is evaluated as the dependent variable or output. The results showed that the feed rate is the most significant factors in increasing the surface roughness value followed by the radial depth of cut and lastly the axial depth of cut. In contrary, the surface becomes smoother with increasing the cutting speed. From a comparison of both methods, the ANN model delivered a better accuracy than the RSM model.

Trend of field data on pipe wall thinning for BWR power plants

International Nuclear Information System (INIS)

Hakii, Junichi; Hiranuma, Naoki; Hidaka, Akitaka

2009-01-01

Strongly motivated by every stakeholder not to repeat Mihama Nuclear Power Station pipe rupture accident in August 2004, JSME Main Committee on Codes and Standards on Power Generation Facilities immediately launched a special task force to develop Rules on Pipe Wall Thinning Management for BWR, PWR and fossil Power Plants respectively. The authors describes the process of the development of Rules for BWR Power Plans from the view point of collections and analysis of fields data of pipe wall thinning. Through its activities, the authors confirmed the existing findings, like the effect of Oxygen injection, turbulence and dependence on coolant temperature, derived from series of laboratory-scaled experiments in FAC and coolant velocities effects in LDI. Further based upon the said proven findings with field data, they explain the adequacy of major concept of the rule such as separate treatment of FAC (Flow Accelerated Corrosion) and LDI (Liquid Droplet Impingement). (author)

Size Control of Porous Silicon-Based Nanoparticles via Pore-Wall Thinning.

Science.gov (United States)

Secret, Emilie; Leonard, Camille; Kelly, Stefan J; Uhl, Amanda; Cozzan, Clayton; Andrew, Jennifer S

2016-02-02

Photoluminescent silicon nanocrystals are very attractive for biomedical and electronic applications. Here a new process is presented to synthesize photoluminescent silicon nanocrystals with diameters smaller than 6 nm from a porous silicon template. These nanoparticles are formed using a pore-wall thinning approach, where the as-etched porous silicon layer is partially oxidized to silica, which is dissolved by a hydrofluoric acid solution, decreasing the pore-wall thickness. This decrease in pore-wall thickness leads to a corresponding decrease in the size of the nanocrystals that make up the pore walls, resulting in the formation of smaller nanoparticles during sonication of the porous silicon. Particle diameters were measured using dynamic light scattering, and these values were compared with the nanocrystallite size within the pore wall as determined from X-ray diffraction. Additionally, an increase in the quantum confinement effect is observed for these particles through an increase in the photoluminescence intensity of the nanoparticles compared with the as-etched nanoparticles, without the need for a further activation step by oxidation after synthesis.

Flow rates through earthen, geomembrane ampersand composite cut-off walls

International Nuclear Information System (INIS)

Tachavises, C.; Benson, C.H.

1997-01-01

Flow rates through soil-bentonite (SIB), geomembrane (GM), and composite geomembrane-soil (CGS) cut-off walls were determined using a numerical model of ground water flow. Various geological and wall conditions were simulated. Results of the simulations show that flow rates past all wall types are affected by hydraulic conductivities of the aquifer and underlying confining layer. Flow rates past GM walls with perfect joints are very low, provided the confining layer has low hydraulic conductivity. However, if a small fraction of the joints are defective, GM walls can be ineffective in blocking flow. CGS walls with a low hydraulic conductivity shell are less sensitive to joint defects. CGS walls with good shells typically have lower flow rates than SB and GM walls, even if the CGS wall contains defective joints

On the characteristics and application of thin wall welded titanium tubes for heat transfer

International Nuclear Information System (INIS)

Nishimura, Takashi; Miyamoto, Yoshiyuki

1985-01-01

Because of the excellent corrosion resistance, thin wall welded titanium tubes have become to be used in large number as the heat transfer tubes of condensers and seawater desalting plants using seawater in place of conventional copper alloy tubes. Especially in nuclear power plants, the all titanium condensers using thin wall welded titanium tubes and titanium tube plates were adopted in the almost all plants under construction or expected to be constructed. In this report, the various characteristics of thin wall welded titanium tubes required for using them as heat transfer tubes, such as corrosion resistance, heat transfer characteristics, fatigue strength and expanding characteristics, are outlined, and the state of use is described. At first, relatively thick seamless titanium tubes were used for chemical industry, but thereafter, due to the advance of the mass production techniques, the welded titanium tubes of less than 0.7 mm thickness and high quality have become to be supplied at low cost. In 1969, titanium tubes were used for the first time in Japan for the air cooler in the condenser of Akita Power Station, Tohoku Electric Power Co., Inc. The features of titanium are small specific gravity, small linear expansion coefficient and small Young's modulus. (Kako, I.)

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

Directory of Open Access Journals (Sweden)

Ted eBotha

2013-08-01

Full Text Available 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 cells, whilst the late metaphloem, contains thick-walled sieve tubes that lack companion cells. Thick-walled sieve tubes are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube-companion cell complexes, thick-walled sieve tubes are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the thin walled sieve tubes. 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 to 7 million year 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.

Cellular automaton modelling of ductile iron microstructure in the thin wall casting

International Nuclear Information System (INIS)

Burbelko, A A; Gurgul, D; Kapturkiewicz, W; Górny, M

2012-01-01

The mathematical model of the globular eutectic solidification in 2D was designed. Proposed model is based on the Cellular Automaton Finite Differences (CA-FD) calculation method. Model has been used for studies of the primary austenite and of globular eutectic grains growth during the ductile iron solidification in the thin wall casting. Model takes into account, among other things, non-uniform temperature distribution in the casting wall cross-section, kinetics of the austenite and graphite grains nucleation, and non-equilibrium nature of the interphase boundary migration.

Analysis of moderately thin-walled beam cross-sections by cubic isoparametric elements

DEFF Research Database (Denmark)

Høgsberg, Jan Becker; Krenk, Steen

2014-01-01

In technical beam theory the six equilibrium states associated with homogeneous tension, bending, shear and torsion are treated as individual load cases. This enables the formulation of weak form equations governing the warping from shear and torsion. These weak form equations are solved...... numerically by introducing a cubic-linear two-dimensional isoparametric element. The cubic interpolation of this element accurately represents quadratic shear stress variations along cross-section walls, and thus moderately thin-walled cross-sections are effectively discretized by these elements. The ability...

A technology to improve formability for aluminum alloy thin-wall corrugated sheet component hydroforming

Directory of Open Access Journals (Sweden)

Lang Lihui

2015-01-01

Full Text Available The explosively forming projectile (EFP had been traditional adopted for the aluminum thin-walled corrugated sheet, whose deformation range is large but the formability is poor, and this process usually has problems of poor surface quality, long manufacturing cycle and high cost. The active hydroforming process was suggested to solve these issues during EFP. A new technology named as blank bulging by turning the upside down active hydroforming technology was proposed to overcome difficulties in non-uniform thickness distribution and cracking failure of corrugated sheet during the conventional hydroforming process. Both numerical simulations and experiments were conducted for this new technology. The result show that the deformation capacity of aluminum alloys can be improved effectively, and the more uniform distribution of wall thickness was obtained by this new method. It is conducted that the new method is universal for thin-walled, shallow drawing parts with complex section.

Standard practice for estimating the approximate residual circumferential stress in straight thin-walled tubing

CERN Document Server

American Society for Testing and Materials. Philadelphia

2007-01-01

1.1 A qualitative estimate of the residual circumferential stress in thin-walled tubing may be calculated from the change in outside diameter that occurs upon splitting a length of the tubing. This practice assumes a linear stress distribution through the tube wall thickness and will not provide an estimate of local stress distributions such as surface stresses. (Very high local residual stress gradients are common at the surface of metal tubing due to cold drawing, peening, grinding, etc.) The Hatfield and Thirkell formula, as later modified by Sachs and Espey, provides a simple method for calculating the approximate circumferential stress from the change in diameter of straight, thin-walled, metal tubing. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Evaluation of local allowable wall thickness of thinned pipe considering internal pressure and bending moment

International Nuclear Information System (INIS)

Kim, J. W.; Park, C. Y.; Kim, B. Y.

2000-01-01

This study proposed the local allowable wall thickness (LAWT) evaluation method for local wall thinned pipe subjected by internal pressure and bending moment. Also, LAWT was evaluated for simplified thinned pipe and the effect of axial extent of thinned area on LAWT was investigated. The results showed that LAWT predicted by present method was thinner, about 50%, than that evaluated by construction code and ASME Code Case N-597, while it was thicker, about 2 times, than that calculated by evaluation model based on pipe experiments. LAWT decreased with increasing axial extent of thinned area and was saturated above axial extent of pipe radius, which was a contrast to the results of ASME Code Case N-597 evaluation. The results of stress analysis with applied loading type indicated that the effect of axial extent of thinned area on LAWT was dependent on loading type considering in the evaluation. That is, the dependence of axial extent on LAWT is determined by magnitude of bending moment, and the contrary trend with axial extent in ASME Code Case is because ASME Code Case N-597 considers only internal pressure in the evaluation

On deformation of thin-walled parts while turning on the lathes

Directory of Open Access Journals (Sweden)

E. V. Arbuzov

2014-01-01

Full Text Available In a number of industries such as aviation engineering, instrumentation engineering, etc. the nonrigid thin-walled parts are a widespread sort of products. For their turning on the lathes the specially designed arrangements are necessary to prevent parts from deformation caused by the action of cutting force and retaining pressure. To create and use the arrangements extra costs are needed, and it, as a consequence, leads to the growth of production price. Potentially, there is another approach. It is to machine using the standard arrangements under special "soft" cutting operation conditions, which are characterized by reduced forces to act on the part, thus decreasing process deformations to the appropriate level. It may be a priori expected that such approach is economically more preferable. Unfortunately, it is difficult to conduct a comparative assessment of these two alternatives to choose a preferable version because of limited data on studies and implementation of the second alternative. Thereupon, to learn the thin-walled deformations versus their treatment conditions is of interest.The aim of the paper is to have general information on topology and elastic deformation value of thin-walled parts, machined on the lathes. The objective is to assess a perspective for further potentially possible activities to develop a concept of machining the thin-walled parts with controlled deformation due to selecting the "soft" cutting operation conditions.The paper studies the thin-walled steel parts of class "Tube" and "Disk" in the role of force action with their dimensions within the range of 5-200 mm for the length, 60-250 mm for diameter, and 4-25 mm for the wall thickness. It considers a chucked work-holding scheme and two machining types, namely external turning cut (for parts of class "Tube" and cross butt turning (for parts of class "Disk". Three stages of machining have been simulated for each type of machining, namely rough (Ra 12.5; IT10

Status of Joining Thin Sheet and Thin Wall Tubes of 14YWT

Energy Technology Data Exchange (ETDEWEB)

Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Unocic, Kinga A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-09-18

Beginning this fiscal year, the FCRD research project initiated an investigation on joining thin sections of the advanced ODS 14YWT ferritic alloy. Friction stir welding (FSW) was investigated as a method to join thin plate and tubing of 14YWT since it is a solid state joining method that has been shown in past studies to be a promising method for joining plates of ODS alloys, such as 14YWT. However, this study will attempt to be the first to demonstrate if FSW can successfully join thin plates and thin wall tubing of 14YWT. In the first FSW attempt, a 1.06 cm thick plate of 14YWT (SM13 heat) was successfully rolled at 1000ºC to the target thickness of 0.1 cm with no edge cracking. This achievement is a highlight since previous attempts to roll 14YWT plates have resulted in extensive cracking. For the FSW run, a pin tool being developed by the ORNL FSW Process Development effort was used. The first FSW run successfully produced a bead-on-plate weld in the 0.1 cm thick plate. The quality of the weld zone appears very good with no evidence of large defects such as cavities. The microstructural characterization study of the bead-on-plate weld zone has been initiated to compare the results of the microstructure analysis with those obtained in the reference microstructural analysis of the 14YWT (SM13 heat) that showed ultra-fine grain size of 0.43 μm and a high number density of ~2-5 nm sizes oxygen-enriched nanoclusters.

A study on the shell wall thinning causes identified through experiment, numerical analysis and ultrasonic test of high-pressure feedwater heater

International Nuclear Information System (INIS)

Hwang, Kyeong Mo; Woo, Lee; Jin, Tae Eun; Kim, Kyung Hoon

2008-01-01

Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damage, which accelerates as the operation progresses. Several nuclear power plants in Korea have undergone this damage around the impingement baffle - installed downstream of the high-pressure turbine extraction steam line - inside numbers 5A and 5B feedwater heaters. At that point, the extracted steam from the high-pressure turbine consists in the form of two-phase fluid at high temperature, high pressure and high velocity. Since it flows in reverse direction after impinging the impingement baffle, the shell wall of number 5 high-pressure feedwater heater may be affected by flow-accelerated corrosion. This paper describes the comparisons between the numerical analysis results using the FLUENT code and the downscaled experimental data in an effort to determine root causes of the shell wall thinning of the high-pressure feedwater heaters. The numerical analysis and experimental data were also confirmed by the actual wall thickness measured by ultrasonic tests. From the comparison of the results for the local velocity profiles and the wall thinning measurements, the local velocity component only in the y-direction flowing vertically to the shell wall, and not in the x- and z-directions, was analogous to the wall thinning data

State-variable analysis of inelastic deformation of thin-walled tubes. II. Data analysis and simulations

International Nuclear Information System (INIS)

Wire, G.L.; Duncan, D.R.; Cannon, N.S.; Johnson, G.D.; Alexopoulos, P.S.; Li, C.Y.

Inelastic analysis is performed to calculate the deformation of thin-walled, internally pressurized, tube under a variety of loading modes. A state-variable approach was used to describe the material properties. The material parameters of the constitutive equations used were determined based on uniaxial, load relaxation, tensile tests, and internally pressurized tubes under creep and constant-displacement-rate modes of loading. The simulated results were compared with the experimental data. The significance of the comparison is discussed in terms of the validity of a state-variable approach used to describe the deformation properties in mechanical testing

Fiber pigtailed thin wall capillary coupler for excitation of microsphere WGM resonator.

Science.gov (United States)

Wang, Hanzheng; Lan, Xinwei; Huang, Jie; Yuan, Lei; Kim, Cheol-Woon; Xiao, Hai

2013-07-01

In this paper, we demonstrate a fiber pigtailed thin wall capillary coupler for excitation of Whispering Gallery Modes (WGMs) of microsphere resonators. The coupler is made by fusion-splicing an optical fiber with a capillary tube and consequently etching the capillary wall to a thickness of a few microns. Light is coupled through the peripheral contact between inserted microsphere and the etched capillary wall. The coupling efficiency as a function of the wall thickness was studied experimentally. WGM resonance with a Q-factor of 1.14 × 10(4) was observed using a borosilicate glass microsphere with a diameter of 71 μm. The coupler operates in the reflection mode and provides a robust mechanical support to the microsphere resonator. It is expected that the new coupler may find broad applications in sensors, optical filters and lasers.

Estimation of Collapse Moment for Wall Thinned Elbows Using Fuzzy Neural Networks

International Nuclear Information System (INIS)

Na, Man Gyun; Kim, Jin Weon; Shin, Sun Ho; Kim, Koung Suk; Kang, Ki Soo

2004-01-01

In this work, the collapse moment due to wall-thinning defects is estimated by using fuzzy neural networks. The developed fuzzy neural networks have been applied to the numerical data obtained from the finite element analysis. Principal component analysis is used to preprocess the input signals into the fuzzy neural network to reduce the sensitivity to the input change and the fuzzy neural networks are trained by using the data set prepared for training (training data) and verified by using another data set different (independent) from the training data. Also, two fuzzy neural networks are trained for two data sets divided into the two classes of extrados and intrados defects, which is because they have different characteristics. The relative 2-sigma errors of the estimated collapse moment are 3.07% for the training data and 4.12% for the test data. It is known from this result that the fuzzy neural networks are sufficiently accurate to be used in the wall-thinning monitoring of elbows

Failure probability assessment of wall-thinned nuclear pipes using probabilistic fracture mechanics

International Nuclear Information System (INIS)

Lee, Sang-Min; Chang, Yoon-Suk; Choi, Jae-Boong; Kim, Young-Jin

2006-01-01

The integrity of nuclear piping system has to be maintained during operation. In order to maintain the integrity, reliable assessment procedures including fracture mechanics analysis, etc., are required. Up to now, this has been performed using conventional deterministic approaches even though there are many uncertainties to hinder a rational evaluation. In this respect, probabilistic approaches are considered as an appropriate method for piping system evaluation. The objectives of this paper are to estimate the failure probabilities of wall-thinned pipes in nuclear secondary systems and to propose limited operating conditions under different types of loadings. To do this, a probabilistic assessment program using reliability index and simulation techniques was developed and applied to evaluate failure probabilities of wall-thinned pipes subjected to internal pressure, bending moment and combined loading of them. The sensitivity analysis results as well as prototypal integrity assessment results showed a promising applicability of the probabilistic assessment program, necessity of practical evaluation reflecting combined loading condition and operation considering limited condition

Analysis on Forced Vibration of Thin-Wall Cylindrical Shell with Nonlinear Boundary Condition

Directory of Open Access Journals (Sweden)

Qiansheng Tang

2016-01-01

Full Text Available Forced vibration of thin-wall cylindrical shell under nonlinear boundary condition was discussed in this paper. The nonlinear boundary was modeled as supported clearance in one end of shell and the restraint was assumed as linearly elastic in the radial direction. Based on Sanders’ shell theory, Lagrange equation was utilized to derive the nonlinear governing equations of cylindrical shell. The displacements in three directions were represented by beam functions and trigonometric functions. In the study of nonlinear dynamic responses of thin-wall cylindrical shell with supported clearance under external loads, the Newmark method is used to obtain time history, frequency spectrum plot, phase portraits, Poincare section, bifurcation diagrams, and three-dimensional spectrum plot with different parameters. The effects of external loads, supported clearance, and support stiffness on nonlinear dynamics behaviors of cylindrical shell with nonlinear boundary condition were discussed.

An improved thin film brick-wall model of black hole entropy

CERN Document Server

Liu Wen Biao

2001-01-01

The authors improve the brick-wall model to take only the contribution of a thin film near the event horizon into account. This improvement not only gives them a satisfactory result, but also avoids some drawbacks in the original brick-wall method such as the little mass approximation, neglecting logarithm term, and taking the term L/sup 3/ as the contribution of the vacuum surrounding a black hole. It is found that there is an intrinsic relation between the event horizon and the entropy. The event horizon is the characteristic of a black hole, so the entropy calculating of a black hole is also naturally related to its horizon. (12 refs).

No rotating U.S. Testing of thin walled tubes

International Nuclear Information System (INIS)

Furlan, J.; Boulanger, G.; Mogavero, R.

1981-07-01

Thin walled tube ultrasonic testing is performed, with Lamb waves, using annular transducers and conical or helicoidal mirrors. The main advantage of this already known system is dispensing with rotation of tube and/or transducer. High speed control (30 cm/s and more) is then allowed. The present paper describes the parameters influencing the sensitivity has been improved by searching, theoretically and practically, the best suited Lamb wave modes, and by using transducers which are well characterized. Practical example of cladding tube U.S. testing is described

Development of NDT simulator with method of mapping for detection of pipe wall thinning using EMAT

International Nuclear Information System (INIS)

Yamaguchi, Hiroshi; Kojima, Fumio; Kosaka, Daigo

2009-01-01

This paper is concerned with a simulator related to nondestructive test using Electromagnetic Acoustic Transducer (EMAT). The simulator developed here can be applied to pipe wall thinning of stainless steel used in nuclear power plants. First, mathematical models for the inspection are given by a transient eddy current equation and by a time dependent elastic wave equation in two dimensions. Secondly, shape of pipe wall thinning is modeled by B-spline function and is applied to the mathematical models using method of mapping. Finally, the validity of the proposed simulator is shown through numerical experiment. (author)

A consideration on pipe-wall thinning mechanisms from an aspect of fluid-mechanics

International Nuclear Information System (INIS)

Inada, Fumio; Yoneda, Kimitoshi; Morita, Ryo; Fujiwara, Kazutoshi; Furuya, Masahiro

2008-01-01

The contribution of the fluid mechanics to the piping wall thinning phenomena was investigated. It was shown that the fluid force to the wall was quite different between flow accelerated corrosion (FAC) and erosion. The turbulent mass transfer, which is one of the primary factors of FAC, was analogous to the turbulent heat transfer. The model that the molecular transport in the viscous sublayer nearby soon of wall was predominant was practicable. In addition, the mass transport was predicted using commercial codes of computational fluid dynamics. Some prediction results of the mass transfer in orifice and the elbow using above techniques were explained. (author)

Printable Thin Film Supercapacitors Using Single-Walled Carbon Nanotubes

KAUST Repository

Kaempgen, Martti

2009-05-13

Thin film supercapacitors were fabricated using printable materials to make flexible devices on plastic. The active electrodes were made from sprayed networks of single-walled carbon nanotubes (SWCNTs) serving as both electrodes and charge collectors. Using a printable aqueous gel electrolyte as well as an organic liquid electrolyte, the performances of the devices show very high energy and power densities (6 W h/kg for both electrolytes and 23 and 70 kW/kg for aqueous gel electrolyte and organic electrolyte, respectively) which is comparable to performance in other SWCNT-based supercapacitor devices fabricated using different methods. The results underline the potential of printable thin film supercapacitors. The simplified architecture and the sole use of printable materials may lead to a new class of entirely printable charge storage devices allowing for full integration with the emerging field of printed electronics. © 2009 American Chemical Society.

PHYSICAL BASES OF SYSTEMS CREATION FOR MAGNETIC-IMPULSIVE ATTRACTION OF THIN-WALLED SHEET METALS

Directory of Open Access Journals (Sweden)

Y. Batygin

2009-01-01

Full Text Available The work is dedicated to the physical base of systems creating for the thin-walled sheet metals magnetic pulse attraction. Some practical realization models of the author’s suggestions are represented.

Domain wall conductivity in semiconducting hexagonal ferroelectric TbMnO3 thin films

International Nuclear Information System (INIS)

Kim, D J; Gruverman, A; Connell, J G; Seo, S S A

2016-01-01

Although enhanced conductivity of ferroelectric domain boundaries has been found in BiFeO 3 and Pb(Zr,Ti)O 3 films as well as hexagonal rare-earth manganite single crystals, the mechanism of the domain wall conductivity is still under debate. Using conductive atomic force microscopy, we observe enhanced conductance at the electrically-neutral domain walls in semiconducting hexagonal ferroelectric TbMnO 3 thin films where the structure and polarization direction are strongly constrained along the c-axis. This result indicates that domain wall conductivity in ferroelectric rare-earth manganites is not limited to charged domain walls. We show that the observed conductivity in the TbMnO 3 films is governed by a single conduction mechanism, namely, the back-to-back Schottky diodes tuned by the segregation of defects. (paper)

Evaluation of fracture mode for local wall-thinned pipes

International Nuclear Information System (INIS)

Herman, Irwan; Suzuki, Tomohisa; Sato, Yasumoto; Meshii, Toshiyuki

2007-01-01

In this study, by referring to our burst pressure tests results, firstly, the effects of flaw length δ z and pipe size (mean radius R) on burst pressure p f were investigated by using Finite Element Method (FEM). Then, fracture mode evaluation was made by using history data of strain ratio ε z /ε θ along with load increment. Furthermore, the effect of flaw depth t 1 on fracture mode was studied and finally, the evaluation method of fracture mode for local wall-thinned pipes was introduced. (author)

Fluid-structure-interaction analysis for welded pipes with flow-accelerated corrosion wall thinning

Energy Technology Data Exchange (ETDEWEB)

Sun, L.; Ding, Y., E-mail: lan.sun@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

2016-06-15

The flow-accelerated corrosion (FAC) entrance effect results in enhanced wall thinning immediately downstream of a weld if the weld connects an upstream FAC-resistant material with a downstream less resistant material. The weld regions, especially those with local repairs, are susceptible to cracking due to the high residual stresses induced by fabrication. The combined effects of the FAC entrance effect and high stresses at a weld might compromise the structural integrity of the piping and lead to a failure. Weld degradation by FAC entrance effect has been observed at nuclear and fossil power plants. This paper describes an application using fluid-structure-interaction (FSI) modelling to study the combined effects of FAC wall thinning, weld residual stresses, and in-service loads on welded structures. Simplified cases analyzed were based on CANDU outlet feeder conditions. The analysis includes the flow and mass transfer modelling of the FAC entrance effect using computational fluid dynamics (CFD) and nonlinear structural analyses of the welded structures with wall thinning and an assumed weld residual stress and strain distribution. The FSI analyses were performed using ANSYS Workbench, an integrated platform that enables the coupling of CFD and structural analysis solutions. The obtained results show that the combination of FAC, weld residual stresses, in-service loads (including the internal pressure) and (or) extreme loads could cause high stresses and affect the integrity of the welded pipes. The present work demonstrated that the FSI modelling can be used as an effective approach to assess the integrity of welded structures. (author)

Cellular automaton modeling of ductile iron microstructure in the thin wall

Directory of Open Access Journals (Sweden)

A.A. Burbelko

2011-10-01

Full Text Available The mathematical model of the globular eutectic solidification in 2D was designed. Proposed model is based on the Cellular Automaton Finite Differences (CA-FD calculation method. Model has been used for studies of the primary austenite and of globular eutectic grains growth during the solidification of the ductile iron with different carbon equivalent in the thin wall casting. Model takes into account, among other things, non-uniform temperature distribution in the casting wall cross-section, kinetics of the austenite and graphite grains nucleation, and non-equilibrium nature of the interphase boundary migration. Solidification of the DI with different carbon equivalents was analyzed. Obtained results were compared with the solidification path calculated by CALPHAD method.

Development of laser cladding technology for maintenance of pipe wall thinning

International Nuclear Information System (INIS)

Terada, Takaya; Nishimura, Akihiko; Oka, Kiyoshi

2011-01-01

We are developing the laser welding and cladding device for the maintenance of heat exchanger pipes. In the case of flow accelerated corrosion where pipe wall thinning occurred after a long time operation, laser cladding is mostly expected. A laser processing head was proposed in order to access the pipe wall. A composite-type optical fiber scope was used for real time observation and laser processing. An air-cooled compact fiber laser was used for spot heating. We present the concept of the laser cladding device which have the following features: 1) Wire feeding modules, 2) Module capable of laser irradiation in the vertical heat exchanger pipe, 3) Assist gas injection module. (author)

The analysis of thin walled composite laminated helicopter rotor with hierarchical warping functions and finite element method

Science.gov (United States)

Zhu, Dechao; Deng, Zhongmin; Wang, Xingwei

2001-08-01

In the present paper, a series of hierarchical warping functions is developed to analyze the static and dynamic problems of thin walled composite laminated helicopter rotors composed of several layers with single closed cell. This method is the development and extension of the traditional constrained warping theory of thin walled metallic beams, which had been proved very successful since 1940s. The warping distribution along the perimeter of each layer is expanded into a series of successively corrective warping functions with the traditional warping function caused by free torsion or free bending as the first term, and is assumed to be piecewise linear along the thickness direction of layers. The governing equations are derived based upon the variational principle of minimum potential energy for static analysis and Rayleigh Quotient for free vibration analysis. Then the hierarchical finite element method is introduced to form a numerical algorithm. Both static and natural vibration problems of sample box beams are analyzed with the present method to show the main mechanical behavior of the thin walled composite laminated helicopter rotor.

Characterization of non-calcareous 'thin' red clay from south-eastern Brazil: applicability in wall tile manufacture

Energy Technology Data Exchange (ETDEWEB)

Sousa, S.J.G.; Holanda, J.N.F., E-mail: sidnei_rjsousa@yahoo.com.br, E-mail: holanda@uenf.br [Grupo de Materiais Ceramicos - LAMAV-CCT, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ (Brazil)

2012-04-15

In this work the use of 'thin' red clay from south-eastern Brazil (Campos dos Goytacazes, RJ) as raw material for the manufacture of wall tile was investigated. A wide range of characterization techniques was employed, including X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), grain-size analysis, and thermogravimetric analysis. The wall tile body was prepared by the dry process. The tile pieces were uniaxially pressed and fired between 1080 - 1180 deg C using a fast-firing cycle. The following technological properties were determined: linear shrinkage, water absorption, apparent density, and flexural strength. The development of the microstructure was followed by SEM and XRD analyses. It was found that the 'thin' red clay is kaolinitic type containing a substantial amount of quartz. The results also showed that the 'thin' red clay could be used in the manufacture of wall tiles, as they present properties compatible with those specified for class BIII of ISO 13006 standard. (author)

Fracture mechanics of thin wall cylindrical pressure vessels: an interim review

International Nuclear Information System (INIS)

Kurtz, R.J.; Olson, N.J.

1977-08-01

The report is a result of activities in the LMFBR Fuel Rod Transient Performance Program sponsored by the LMFBR Branch of the Division of Project Management, U.S. Nuclear Regulatory Commission. One of the objectives is to develop predictions relative to the length, direction, and rate of growth of cladding rips subsequent to (or concurrent with) the initial cladding breach during unprotected transients. To provide a basis for evaluation, Battelle, Pacific Northwest Laboratories has reviewed most available fracture mechanics assessments relative to thin-wall cylindrical pressure vessels. The purpose of the report is to review the various fracture mechanics models and to describe the pertinent fracture parameters. It is intended to provide a formal basis for assessing future analytical predictions of fracture behavior of materials exposed to transient LMFBR thermal and mechanical loading conditions. In addition, the report is expected to provide reference material for evaluating or developing experimental programs required to properly address the problem of predicting fracture behavior of materials during transient events

Acoustic emission monitoring during hydrotest of a thin wall pressure vessel

International Nuclear Information System (INIS)

Fontana, E.; Grugni, G.; Panzani, C.; Pirovano, B.; Possa, G.; Tonolini, F.

1976-01-01

Results are presented of the acoustic emission monitoring during hydrotests of a thin wall steel pressure vessel. Location of acoustic sources was based on longitudinal wave front detection. The careful calibration of the three sensors used for acoustic source location was found to be very useful, and allowed an accurate location error analysis. Acoustic emission in the hydrotests was found to be due mainly to stress release in weld seams

Experimental Investigation of Chatter Dynamics in Thin-walled Tubular Parts Turning

OpenAIRE

GERASIMENKO, Artem; GUSKOV, Mikhail; LORONG, Philippe; DUCHEMIN, Jérôme; GOUSKOV, Alexander

2016-01-01

Chatter prediction is nowadays frequently carried out for machining operations involving deformable parts or tools. These analyses are commonly based on the uncoupled elements of the system: frequency response of the deformable parts under non-rotating conditions and cutting law. The present investigation puts forward the dynamics of a thin-walled tubular part during straight axial turning undergoing chatter instability. Studied system’s peculiarities include quasi-static nominal cutting cond...

Experimental validation of error in temperature measurements in thin walled ductile iron castings

DEFF Research Database (Denmark)

Pedersen, Karl Martin; Tiedje, Niels Skat

2007-01-01

An experimental analysis has been performed to validate the measurement error of cooling curves measured in thin walled ductile cast iron. Specially designed thermocouples with Ø0.2 mm thermocouple wire in Ø1.6 mm ceramic tube was used for the experiments. Temperatures were measured in plates...

Coupled Static and Dynamic Buckling Modelling of Thin-Walled Structures in Elastic Range Review of Selected Problems

Directory of Open Access Journals (Sweden)

Kołakowski Zbigniew

2016-06-01

Full Text Available A review of papers that investigate the static and dynamic coupled buckling and post-buckling behaviour of thin-walled structures is carried out. The problem of static coupled buckling is sufficiently well-recognized. The analysis of dynamic interactive buckling is limited in practice to columns, single plates and shells. The applications of finite element method (FEM or/and analytical-numerical method (ANM to solve interaction buckling problems are on-going. In Poland, the team of scientists from the Department of Strength of Materials, Lodz University of Technology and co-workers developed the analytical-numerical method. This method allows to determine static buckling stresses, natural frequencies, coefficients of the equation describing the post-buckling equilibrium path and dynamic response of the plate structure subjected to compression load and/or bending moment. Using the dynamic buckling criteria, it is possible to determine the dynamic critical load. They presented a lot of interesting results for problems of the static and dynamic coupled buckling of thin-walled plate structures with complex shapes of cross-sections, including an interaction of component plates. The most important advantage of presented analytical-numerical method is that it enables to describe all buckling modes and the post-buckling behaviours of thin-walled columns made of different materials. Thin isotropic, orthotropic or laminate structures were considered.

PRODUCTION OF HIGHER STRENGTH THIN WALLED GLOW DISCHARGE POLYMER SHELLS FOR CRYOGENIC EXPERIMENTS AT OMEGA

International Nuclear Information System (INIS)

NIKROO, A; CZECHOWICZ, DG; CASTILLO, ER; PONTELANDOLFO, JM

2002-01-01

OAK A271 PRODUCTION OF HIGHER STRENGTH THIN WALLED GLOW DISCHARGE POLYMER SHELLS FOR CRYOGENIC EXPERIMENTS AT OMEGA. Thin walled polymer shells are needed for OMEGA cryogenic laser experiments. These capsules need to be about 900 (micro)m in diameter and as thin as possible (approx 1-2 (micro)m), while having enough strength to be filled with DT as fast as possible to about 1000 atm. The authors have found that by optimizing the coating parameters in the glow discharge polymer (GDP) deposition system, traditionally used for making ICF targets, they can routinely make robust, ∼ 1.5 (micro)m thick, 900 (micro)m diameter GDP shells with buckle strengths of over 0.3 atm. This is twice the strength of shells made prior to the optimization and is comparable to values quoted for polyimide shells. In addition, these shells were found to be approximately three times more permeable and over 20% denser than previously made GDP shells. The combination of higher strength and permeability is ideal for direct drive cryogenic targets at OMEGA. Shells as thin as 0.5 (micro)m have been made. In this paper, the authors discuss the shell fabrication process, effects of modifying various GDP deposition parameters on shell properties and chemical composition

Stiffness Matrix of Thin-Walled Open Bar Subject to Bending, Bending Torsion and Shift of Cross Section Middle Surface

Science.gov (United States)

Panasenko, N. N.; Sinelschikov, A. V.

2017-11-01

One of the main stages in the analysis of complex 3D structures and engineering constructions made of thin-walled open bars using FEM is a stiffness matrix developing. Taking into account middle surface shear deformation caused by the work of tangential stresses in the formula to calculate a potential energy of thin-walled open bars, the authors obtain an important correction at calculation of the bar deformation and fundamental frequencies. The results of the analysis of the free end buckling of a cantilever H-bar under plane bending differ from exact solution by 0.53%. In the course of comparison of the obtained results with the cantilever bar buckling regardless the middle surface shear deformation, an increase made 16.6%. The stiffness matrix of a thin-walled open bar developed in the present work can be integrated into any software suite using FEM for the analysis of complex 3-D structures and engineering constructions with n-freedoms.

Basic Principles of Thin-Walled Open Bars Taking into Account Where Influence Shifts of Cross Sections are Concerned

Science.gov (United States)

Panasenko, N. N.; Sinelschikov, A. V.

2017-11-01

The finite element method is considered to be the most effective in relation to the calculation of strength and stability of buildings and engineering constructions. As a rule, for the modelling of supporting 3-D frameworks, finite elements with six degrees of freedom are used in each of the nodes. In practice, such supporting frameworks represent the thin-walled welded bars and hot-rolled bars of open and closed profiles in which cross-sectional deplanation must be taken into account. This idea was first introduced by L N Vorobjev and brought to one of the easiest variants of the thin-walled bar theory. The development of this approach is based on taking into account the middle surface shear deformation and adding the deformations of a thin-walled open bar to the formulas for potential and kinetic energy; these deformations depend on shearing stress and result in decreasing the frequency of the first tone of fluctuations to 13%. The authors of the article recommend taking into account this fact when calculating fail-proof dynamic systems.

Development of a guided wave simulator and its application to monitoring of pipe wall thinning

International Nuclear Information System (INIS)

Furukawa, Akinori; Kojima, Fumio

2009-01-01

Motivated by growing demand for quantitative nondestructive evaluation of pipe wall thinning, the aim of this paper is to develop a simulator for guided wave analysis. First, an inspection system can be represented by a linear elastic system in cylindrical coordinates. Secondly a dynamical numerical scheme for wave propagation on a pipe wall is proposed based on Fourier-Galerkin approach. Finally, the effectiveness and validity of the proposed method are shown in computational experiments. (author)

Dynamic analysis of horizontal axis wind turbine by thin-walled beam theory

Science.gov (United States)

Wang, Jianhong; Qin, Datong; Lim, Teik C.

2010-08-01

A mixed flexible-rigid multi-body mathematical model is applied to predict the dynamic performance of a wind turbine system. Since the tower and rotor are both flexible thin-walled structures, a consistent expression for their deformations is applied, which employs a successive series of transformations to locate any point on the blade and tower relative to an inertial coordinate system. The kinetic and potential energy terms of each flexible body and rigid body are derived for use in the Lagrange approach to formulate the wind turbine system's governing equation. The mode shapes are then obtained from the free vibration solution, while the distributions of dynamic stress and displacement of the tower and rotor are computed from the forced vibration response analysis. Using this dynamic model, the influence of the tower's stiffness on the blade tip deformation is studied. From the analysis, it is evident that the proposed model not only inherits the simplicity of the traditional 1-D beam element, but also able to provide detailed information about the tower and rotor response due to the incorporation of the flexible thin-walled beam theory.

Effects of water chemistry and fluid dynamics on wall thinning behavior. Part 1. Development of FAC model focused on water chemistry and composition of material

International Nuclear Information System (INIS)

Fujiwara, Kazutoshi; Domae, Masafumi; Ohta, Joji; Yoneda, Kimitoshi; Inada, Fumio

2009-01-01

Flow Accelerated Corrosion (FAC), which is one of the important subjects at fossil and nuclear power plans, is caused by the accelerated dissolution of protective oxide film due to the turbulent flow. The influence factors on FAC such as water chemistry, material, and fluid dynamics are closely related to the oxide property so that the risk of FAC can be reduced by the suitable control of water chemistry. There are some FAC models and evaluation codes of FAC rate. Some of them are used in wall thinning management of nuclear power plant in some country. Nevertheless, these FAC codes include many empirical parameters so that some uncertainty to evaluate the synergistic effectiveness of factors are the controversial point for the application of FAC code to wall thinning management in Japanese nuclear power plant. In this study, a FAC model that can evaluate the effect of temperature, NH3 concentration, chromium content, and dissolved oxygen concentration on FAC rate was developed by considering the diffusion of dissolved species. The critical dissolved oxygen concentration, which can inhibit FAC, was also calculated by this model. (author)

Resistive Wall Growth Rate Measurements in the Fermilab Recycler

Energy Technology Data Exchange (ETDEWEB)

Ainsworth, R. [Fermilab; Adamson, P. [Fermilab; Burov, A. [Fermilab; Kourbanis, I. [Fermilab

2016-10-05

Impedance could represent a limitation of running high intensity beams in the Fermilab recycler. With high intensity upgrades foreseen, it is important to quantify the impedance. To do this,studies have been performed measuring the growth rate of presumably the resistive wall instability. The growth rates at varying intensities and chromaticities are shown. The measured growth rates are compared to ones calculated with the resistive wall impedance.

Analytical and numerical calculations of resistive wall impedances for thin beam pipe structures at low frequencies

Energy Technology Data Exchange (ETDEWEB)

Niedermayer, U., E-mail: u.niedermayer@gsi.de [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder, Schlossgartenstrasse 8, 64289 Darmstadt (Germany); Boine-Frankenheim, O. [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder, Schlossgartenstrasse 8, 64289 Darmstadt (Germany)

2012-09-21

The resistive wall impedance is one of the main sources for beam instabilities in synchrotrons and storage rings. The fast ramped SIS18 synchrotron at GSI and the projected SIS100 synchrotron for FAIR both employ thin (0.3 mm) stainless steel beam pipes in order to reduce eddy current effects. The lowest betatron sidebands are at about 100 kHz, which demands accurate impedance predictions in the low frequency (LF) range where the beam pipe and possibly also the structures behind the pipe are the dominating impedance sources. The longitudinal and transverse resistive wall impedances of a circular multi-layer pipe are calculated analytically using the field matching technique. We compare the impedances obtained from a radial wave model, which corresponds to the setup used in bench measurements, with the axial wave model, which corresponds to an actual beam moving with relativistic velocity. For thin beam pipes the induced wall current and the corresponding shielding properties of the pipe are important. In both models the wall current is obtained analytically. The characteristic frequencies for the onset of the wall current are calculated from equivalent lumped element circuits corresponding to the radial model. For more complex structures, like the SIS100 beam pipe, we use a numerical method, in which the impedance is obtained from the total power loss. The method is validated by the analytic expressions for circular beam pipes.

Temperature measurement during solidification of thin wall ductile cast iron. Part 2: Numerical simulations

DEFF Research Database (Denmark)

Pedersen, Karl Martin; Tiedje, Niels Skat

2008-01-01

Temperature measurements in castings are carried out with thermocouples (TC’s), which are inserted in the melt. The TC influence solidification of the casting, especially in thin wall castings where the heat content of the melt is small compared to the cooling power of the TC. A numerical analysi...

Analysis of the ballooning deformation of an internally pressurized thin-wall tube during fast thermal transients

International Nuclear Information System (INIS)

Lin, E.I.H.

1977-01-01

A large-strain time-dependent thermoplastic analysis has been developed for the ballooning deformation of a thin-wall tube subjected to internal pressure, axial loading, and fast thermal transients. This deformation initiates with the onset of plastic instability in the material, the onset being determined by a plastic-instability criterion for strain-rate sensitive materials. The interaction among the local ballooning geometry, the state of stress, and the plastic flow process was considered, and integration of the flow equations yields the local curvature and the states of stress and strain in the vicinity of the maximum ballooning site. The effects of axial constraint and heating rate were also discussed. The analysis was applied to a LWR Zircaloy cladding subjected to a constant heating rate and a range of internal pressures. The results agree very well with experimental strain-time data obtained from tube-burst tests. In most cases, the time of rupture was accurately predicted despite the lack of complete material-property data

Study on structural integrity of thinned wall piping against seismic loading-overview and future program

International Nuclear Information System (INIS)

Nakamura, Izumi; Otani, Akihito; Shiratori, Masaki

2005-01-01

In order to clarify the behavior of thinned wall pipes under seismic events, cyclic in-plane and/or out-of-plane bending tests on thinned straight pipe and elbow and also shaking table tests using degraded piping system models were conducted. Relation between the failure mode and thinned condition and the influence of the final failure mode of degraded piping systems were investigated. In addition to these experiments, elastic-plastic FEM analysis using ABAQUS were conducted on thinned piping elements. It has been found that the strain concentrated point could be predicted and the cause of its generation could be explained by the simulated deformation behavior of the pipe. In order to predict the piping system's maximum response under elastic-plastic response, a simple response prediction method was proposed. Further tests and safety margin analyses of thinned pipes against seismic loading will be performed. (T. Tanaka)

Impact of Thin-Walled Projectiles with Concrete Targets

Directory of Open Access Journals (Sweden)

Rayment E. Moxley

1995-01-01

Full Text Available An experimental program to determine the response of thin-walled steel projectiles to the impact with concrete targets was recently conducted. The projectiles were fired against 41-MPa concrete targets at an impact velocity of 290 m/s. This article contains an outline of the experimental program, an examination of the results of a typical test, and predictions of projectile deformation by classical shell theory and computational simulation. Classical shell analysis of the projectile indicated that the predicted impact loads would result in circumferential buckling. A computational simulation of a test was conducted with an impact/penetration model created by linking a rigid-body penetration trajectory code with a general-purpose finite element code. Scientific visualization of the resulting data revealed that circumferential buckling was induced by the impact conditions considered.

Local conductivity and the role of vacancies around twin walls of (001)-BiFeO3 thin films

NARCIS (Netherlands)

Farokhipoor, S.; Noheda, Beatriz

2012-01-01

BiFeO3 thin films epitaxially grown on SrRuO3-buffered (001)-oriented SrTiO3 substrates show orthogonal bundles of twin domains, each of which contains parallel and periodic 71 degrees domain walls. A smaller amount of 109 degrees domain walls are also present at the boundaries between two adjacent

Wall relaxation rates for an optically pumped NA vapor

International Nuclear Information System (INIS)

Swenson, D.R.; Anderson, L.W.

1986-01-01

The wall relaxation rates for an optically pumped Na vapor have been measured for a variety of wall surfaces. We find that fluorocarbon rubber (Fluorel, Viton) and organosilicones (silicone rubber, dry film) at a temperature of 250 C have respectively relaxation rates that correspond on the average to 10 to 15 and 200 to 500 bounces before depolarization occurs. 7 refs., 3 figs

Acoustic emission monitoring during hydrotests of a thin wall pressure vessel

International Nuclear Information System (INIS)

Fontana, E.; Grugni, G.; Panzani, C.; Pirovano, B.; Possa, G.; Tonolini, F.

1975-01-01

The results are presented of an acoustic emission monitoring performed during hydrotests of a thin wall steel pressure vessel. The location of acoustic sources was based on longitudinal wave front detection. The careful calibration of the three sensors instrumentation system used for acoustic source location was found to be useful, and alllowed an accurate location error analysis. Acoustic emission in the hydrotests was found to be mainly due to stress release in weld seams. (Fontana, E.; Grugni, G.; Panzani, C.; Pirovano, B.; Possa, G.; Tonolini, F.)

Fuel retention properties of thin-wall glass target in low temperature

International Nuclear Information System (INIS)

Gao Dangzhong; Huang Yong; Tang Yongjian; Wen Shuhuai

2001-01-01

In room temperature the fuel gas storage half-life of the thin-wall (wall-thickness less than 1μm) glass microsphere is only a few days, it is difficult to be used for ICF. To efficiently prolong the half-life of such type targets, and meet the need of ICF experiments, the special device for storing the targets was developed. All the targets are immerged in liquid-nitrogen (LN 2 ), after being sealed in vacuum. During this period the change of Si 1.74 keV X-ray counts were measured a few times with the low energy X-ray multi-channel analyzer. The results of experiment indicate that, in the environment of -196 degree C, the fuel storage half-life of target has been successfully extended to 100-300 d from 3-10 d. However, the surface roughness of target was not obviously changed

Magnetic moment jumps in flat and nanopatterned Nb thin-walled cylinders

Energy Technology Data Exchange (ETDEWEB)

Tsindlekht, M.I., E-mail: mtsindl@vms.huji.ac.il [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Genkin, V.M.; Felner, I.; Zeides, F.; Katz, N. [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Gazi, Š.; Chromik, Š. [The Institute of Electrical Engineering SAS, Dúbravská cesta 9, 84104 Bratislava (Slovakia); Dobrovolskiy, O.V. [Physikalisches Institut, Goethe University, 60438 Frankfurt am Main (Germany); Physics Department, V. Karazin Kharkiv National University, 61077 Kharkiv (Ukraine); Sachser, R.; Huth, M. [Physikalisches Institut, Goethe University, 60438 Frankfurt am Main (Germany)

2017-02-15

Highlights: • Magnetization curves of as-prepared and patterned thin-walled cylinders were measured in magnetic fields applied parallel to cylinders axis. • Magnetic moment jumps were observed in magnetic fields lower and above Hc1. • Critical current density in isthmus between two antidots is higher than in a film itself. - Abstract: Penetration of magnetic flux into hollow superconducting cylinders is investigated by magnetic moment measurements. The magnetization curves of a flat and a nanopatterned thin-walled superconducting Nb cylinders with a rectangular cross section are reported for the axial field geometry. In the nanopatterned sample, a row of micron-sized antidots (holes) was milled in the film along the cylinder axis. Magnetic moment jumps are observed for both samples at low temperatures for magnetic fields not only above H{sub c1}, but also in fields lower than H{sub c1}, i. e., in the vortex-free regime. The positions of the jumps are not reproducible and they change from one experiment to another, resembling vortex lattice instabilities usually observed for magnetic fields larger than H{sub c1}. At temperatures above 0.66T{sub c} and 0.78T{sub c} the magnetization curves become smooth for the patterned and the as-prepared sample, respectively. The magnetization curve of a reference flat Nb film in the parallel field geometry does not exhibit jumps in the entire range of accessible temperatures.

Research of precise pulse plasma arc powder welding technology of thin-walled inner hole parts

Institute of Scientific and Technical Information of China (English)

Li Zhanming; Du Xiaokun; Sun Xiaofeng; Song Wei

2017-01-01

The inner hole parts played an oriented or supporting role in engineering machinery and equipment,which are prone to appear surface damages such as wear,strain and corrosion.The precise pulse plasma arc powder welding method is used for surface damage repairing of inner hole parts in this paper.The working principle and process of the technology are illustrated,and the microstructure and property of repairing layer by precise pulse plasma powder welding and CO2 gas shielded welding are tested and observed by microscope,micro hardness tester and X-ray residual stress tester etc.Results showed that the substrate deformation of thin-walled inner hole parts samples by precise pulse plasma powder welding is relatively small.The repair layer and substrate is metallurgical bonding,the transition zones (including fusion zone and heat affected zone) are relatively narrow and the welding quality is good.h showed that the thin-walled inner hole parts can be repaired by this technology and equipment.

NUMERICAL ANALYSIS OF THE CRITICAL STATE OF THIN-WALLED STRUCTURE WITH Z-PROFILE CROSS SECTION

Directory of Open Access Journals (Sweden)

Patryk Różyło

2017-03-01

Full Text Available The object of the study was the thin-walled profile with Z-shaped cross section made of the carbon-epoxy composite. Material model was prepared based on the implemented orthotropic properties. The purpose of study was to determine the value of the critical load at which buckling occurs, the form of buckling and operating characteristics in critical condition. In order to achieve this numerical analysis were carried out. Additionally, the effects of the modification in arrangement of layers of the laminate to the stability and strength of thin-walled composite structures was presented. Numerical studies were carried out using commercial simulation software - ABAQUS®. Within the FEM research, both forms of buckling and the associated critical load, dependent on the configuration the layers of the composite were achieved. Analysis of the obtained results, allowed the evaluation of the structure's work in relation to the level of energy consumption or rigidity estimation. In the paper only numerical simulations of the critical state were conducted.

Defect detection of wall thinning defect in pipes using lock-in photo-infrared thermography technique

Energy Technology Data Exchange (ETDEWEB)

Jang, Su Ok; Park, Jong Hyun; Choi, Tae Ho; Jung, Hyun Chul; Kim, Kyoung Suk [Chosun Univ., Gwangju (Korea, Republic of)

2008-07-01

Piping in the Nuclear Power plants (NPP) are mostly consisted of carbon steel pipe. The wall thinning defect is mainly occurred by the affect of the Flow Accelerated Corrosion (FAC) of fluid which flows in carbon steel pipes. This type of defect becomes the cause of damage or destruction of piping. Therefore, it is very important to measure defect which is existed not only on the welding partbut also on the whole field of pipe. Over the years, Infrared Thermography (IRT) has been used as a non destructive testing methods of the various kinds of materials. This technique has many merits and applied to the industrial field but has limitation to the materials. Therefore, this method was combined with lock-in technique. So IRT detection resolution has been progressively improved using lock-in technique. In this paper, the quantitative analysis results of the location and the size of wall thinning defect that is artificially processed inside the carbon steel pipe by using IRT are obtained.

Manufacturing of thin-walled parts for machinery by selective laser melting

Directory of Open Access Journals (Sweden)

Bobyr Vitaliy

2017-01-01

Full Text Available The paper describes the technology of selective laser melting, as well as its capabilities in the manufacture of thin-wall honeycomb energy absorber (HEA. The effect of the technological parameters of the building process on the HEA walls’ thickness is studied. Conformity analysis of the mass-dimensional characteristics of the finished composition with the predefined parameters of the 3D-CAD model is carried out. Dependencies of building parameterson the quality of the manufactured HEA are established, general recommendations for the practical use of technology in the creation of HEAare given.

Differential Hall-sensor Pulsed Eddy Current Probe for the Detection of Wall thinning in an Insulated Stainless Steel Pipe

International Nuclear Information System (INIS)

Park, D. G.; Angani, Chandra S.; Cheong, Y. M.; Kim, C. G.

2010-01-01

The local wall thinning is one of the most important factors to limit the life-extension of large structures, such as the pipe lines in the NPPs. The pipelines are covered with a thermal insulator for low thermal loss. The PEC testing is the promising technological approach to the NDT, and it has been principally developed for the measurement of surface flaws, subsurface flaws and corrosion. In the pulsed eddy current (PEC) technique, the excitation coil is driven by repeated pulses. According to the skin - depth relationship multiple frequency components penetrate to different depths, hence the PEC technique has the potential for bringing up deeper information about the tested sample. Because of the potential advantages of the PEC, prevalent investigations on this technique have been done. In the present study a differential probe which is used in the Pulsed Eddy Current (PEC) system has been fabricated for the detection of wall thinning of insulated pipelines in a nuclear power plant (NPP). This technique can be used as a potential tool to detect the corrosion or the wall thinning of the pipelines without removing the insulation

Magnetic properties, domain-wall creep motion, and the Dzyaloshinskii-Moriya interaction in Pt/Co/Ir thin films

Science.gov (United States)

Shepley, Philippa M.; Tunnicliffe, Harry; Shahbazi, Kowsar; Burnell, Gavin; Moore, Thomas A.

2018-04-01

We study the magnetic properties of perpendicularly magnetized Pt/Co/Ir thin films and investigate the domain-wall creep method of determining the interfacial Dzyaloshinskii-Moriya (DM) interaction in ultrathin films. Measurements of the Co layer thickness dependence of saturation magnetization, perpendicular magnetic anisotropy, and symmetric and antisymmetric (i.e., DM) exchange energies in Pt/Co/Ir thin films have been made to determine the relationship between these properties. We discuss the measurement of the DM interaction by the expansion of a reverse domain in the domain-wall creep regime. We show how the creep parameters behave as a function of in-plane bias field and discuss the effects of domain-wall roughness on the measurement of the DM interaction by domain expansion. Whereas modifications to the creep law with DM field and in-plane bias fields have taken into account changes in the energy barrier scaling parameter α , we find that both α and the velocity scaling parameter v0 change as a function of in-plane bias field.

Influence of circumferential flaw length on internal burst pressure of a wall-thinned pipe

Energy Technology Data Exchange (ETDEWEB)

Tsuji, Masataka, E-mail: tsuji-m@u-fukui.ac.jp [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui, Fukui (Japan); Meshii, Toshiyuki [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui, Fukui (Japan)

2013-02-15

Highlights: ► The effect of θ on p{sub f} was examined by experimental analysis and FEA. ► Here θ is the circumferential angle of a flaw, p{sub f} is the internal burst pressure. ► p{sub f} decreased as θ increased in some cases. ► The effect of θ on p{sub f} should be taken into consideration in evaluating p{sub f}. -- Abstract: This paper examines the effect of the circumferential angle of a flaw θ on the internal burst pressure p{sub f} of pipes with artificial wall-thinned flaws. The effect of θ has conventionally been regarded as unimportant in the evaluation of the p{sub f} of wall-thinned straight pipes. Therefore, a burst pressure equation for an axial crack inside a cylinder (Fig. 1, left), such as Kiefner's equation (Kiefner et al., 1973), has been widely applied (ANSI/ASME B31.G., 1991; Hasegawa et al., 2011). However, the following implicit assumptions notably exist when applying the equation to planar flaws in situations with non-planar flaws. 1)The fracture mode of the non-planar flaw under consideration is identical to that of the crack. 2)The effect of θ on p{sub f}, which is not considered for an axial crack, is small or negligible. However, the experimental results from the systematic burst tests for carbon steel pipes with artificial wall-thinned flaws examined in this paper showed that these implicit assumptions may be incorrect. In this paper the experimental results are evaluated in further detail. The purpose of the evaluation was to clarify the effect of θ on p{sub f}. Specifically, the significance of the flaw configuration (axial length δ{sub z} and wall-thinning ratio t{sub 1}/t) was studied for its effects on θ and p{sub f}. In addition, a simulation of this effect was conducted using a large strain elastic-plastic Finite Element Analysis (FEA) model. As observed from the experimental results, θ tended to affect p{sub f} in cases with large δ{sub z}, and t{sub 1}/t was also correlated with a decrease in p{sub f

Thermoelectric Cooling-Aided Bead Geometry Regulation in Wire and Arc-Based Additive Manufacturing of Thin-Walled Structures

Directory of Open Access Journals (Sweden)

Fang Li

2018-01-01

Full Text Available Wire and arc-based additive manufacturing (WAAM is a rapidly developing technology which employs a welding arc to melt metal wire for additive manufacturing purposes. During WAAM of thin-walled structures, as the wall height increases, the heat dissipation to the substrate is slowed down gradually and so is the solidification of the molten pool, leading to variation of the bead geometry. Though gradually reducing the heat input via adjusting the process parameters can alleviate this issue, as suggested by previous studies, it relies on experience to a large extent and inevitably sacrifices the deposition rate because the wire feed rate is directly coupled with the heat input. This study introduces for the first time an in-process active cooling system based on thermoelectric cooling technology into WAAM, which aims to eliminate the difference in heat dissipation between upper and lower layers. The case study shows that, with the aid of thermoelectric cooling, the bead width error is reduced by 56.8%, the total fabrication time is reduced by 60.9%, and the average grain size is refined by 25%. The proposed technique provides new insight into bead geometry regulation during WAAM with various benefits in terms of geometric accuracy, productivity, and microstructure.

Isotropic damage model and serial/parallel mix theory applied to nonlinear analysis of ferrocement thin walls. Experimental and numerical analysis

Directory of Open Access Journals (Sweden)

Jairo A. Paredes

2016-01-01

Full Text Available Ferrocement thin walls are the structural elements that comprise the earthquake resistant system of dwellings built with this material. This article presents the results drawn from an experimental campaign carried out over full-scale precast ferrocement thin walls that were assessed under lateral static loading conditions. The tests allowed the identification of structural parameters and the evaluation of the performance of the walls under static loading conditions. Additionally, an isotropic damage model for modelling the mortar was applied, as well as the classic elasto-plastic theory for modelling the meshes and reinforcing bars. The ferrocement is considered as a composite material, thus the serial/parallel mix theory is used for modelling its mechanical behavior. In this work a methodology for the numerical analysis that allows modeling the nonlinear behavior exhibited by ferrocement walls under static loading conditions, as well as their potential use in earthquake resistant design, is proposed.

Gas leakage rate through reinforced concrete shear walls: Numerical study

International Nuclear Information System (INIS)

Wang Ting; Hutchinson, Tara C.

2005-01-01

Unlined reinforced concrete shear walls are often used as 'tertiary boundaries' in the United States Department of Energy (DOE) to house dangerous gases. An unanticipated event, such as an earthquake, may cause gases stored inside the walls to disperse into the environment resulting in excess pollution. To address this concern, in this paper, a methodology to numerically predict the gas leakage rate through these shear walls under lateral loading conditions is proposed. This methodology involves finite element and flow rate analysis. Strain distributions are obtained from the finite element analysis, and then used to simulate the crack characteristics on the concrete specimen. The flow rate through the damaged concrete specimen is then estimated using flow rate formulas available from the literature. Results from an experimental specimen are used to evaluate the methodology, and particularly its robustness in the flow rate estimation

Laser and Pressure Resistance Weld of Thin-Wall Cladding for LWR Accident-Tolerant Fuels

Science.gov (United States)

Gan, J.; Jerred, N.; Perez, E.; Haggard, D. C.

2018-02-01

FeCrAl alloy with typical composition of approximately Fe-15Cr-5Al is considered a primary candidate cladding material for light water reactor accident-tolerant fuel because of its superior resistance to oxidation in high-temperature steam compared with Zircaloy cladding. Thin-walled FeCrAl cladding at 350 μm wall thickness is required, and techniques for joining endplug to cladding need to be developed. Fusion-based laser weld and solid-state joining with pressure resistance weld were investigated in this study. The results of microstructural characterization, mechanical property evaluation by tensile testing, and hydraulic pressure burst testing of the welds for the cladding-endplug specimen are discussed.

Effects of microporosity on the elasticity and yielding of thin-walled metallic hollow spheres

International Nuclear Information System (INIS)

Song, Jinliang; Sun, Quansheng; Yang, Zhenning; Luo, Shengmin; Xiao, Xianghui; Arwade, Sanjay R.; Zhang, Guoping

2017-01-01

Knowledge of the mechanical properties of porous metallic hollow spheres (MHS) thin wall is of key importance for understanding the engineering performance of both individual ultralight MHS and the innovative MHS-based bulk foams. This paper presents the first integrated experimental and numerical study to determine the elasticity and yielding of the porous MHS wall and their dependence on its microporosity. Nanoindentation was used to probe the Young's modulus and hardness of the nonporous MHS wall material, and synchrotron X-ray computed tomography (XCT) conducted to obtain its porous microstructure and pore morphology. Three-dimensional finite element modeling was performed to obtain the mechanical response of microcubes with varying porosity trimmed from the XCT-derived real digital model of the porous MHS wall. Results show that both the Young's modulus and yield strength of the porous wall decrease nonlinearly with increasing porosity, and their relationships follow the same format of a power law function and agree well with prior experimental results. The empirical relations also reflect certain features of pore morphology, such as pore connectivity and shape. These findings can shed lights on the design, manufacturing, and modeling of individual MHS and MHS-based foams.

Effects of microporosity on the elasticity and yielding of thin-walled metallic hollow spheres

Energy Technology Data Exchange (ETDEWEB)

Song, Jinliang [Department of Civil Engineering, Northeast Forestry University, Harbin 150040 (China); Department of Civil and Environmental Engineering, University of Massachusetts Amherst, Amherst, MA 01003 (United States); Sun, Quansheng [Department of Civil Engineering, Northeast Forestry University, Harbin 150040 (China); Yang, Zhenning; Luo, Shengmin [Department of Civil and Environmental Engineering, University of Massachusetts Amherst, Amherst, MA 01003 (United States); Xiao, Xianghui [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Arwade, Sanjay R. [Department of Civil and Environmental Engineering, University of Massachusetts Amherst, Amherst, MA 01003 (United States); Zhang, Guoping, E-mail: zhangg@umass.edu [Department of Civil and Environmental Engineering, University of Massachusetts Amherst, Amherst, MA 01003 (United States)

2017-03-14

Knowledge of the mechanical properties of porous metallic hollow spheres (MHS) thin wall is of key importance for understanding the engineering performance of both individual ultralight MHS and the innovative MHS-based bulk foams. This paper presents the first integrated experimental and numerical study to determine the elasticity and yielding of the porous MHS wall and their dependence on its microporosity. Nanoindentation was used to probe the Young's modulus and hardness of the nonporous MHS wall material, and synchrotron X-ray computed tomography (XCT) conducted to obtain its porous microstructure and pore morphology. Three-dimensional finite element modeling was performed to obtain the mechanical response of microcubes with varying porosity trimmed from the XCT-derived real digital model of the porous MHS wall. Results show that both the Young's modulus and yield strength of the porous wall decrease nonlinearly with increasing porosity, and their relationships follow the same format of a power law function and agree well with prior experimental results. The empirical relations also reflect certain features of pore morphology, such as pore connectivity and shape. These findings can shed lights on the design, manufacturing, and modeling of individual MHS and MHS-based foams.

Stress state of thin – walled member of the structure with operation damages under nonuniform loading

Directory of Open Access Journals (Sweden)

В.В. Астанін

2004-01-01

Full Text Available  The publication is dedicated to determining of stress state in particular the stress concentration factors for thin – walled members of the structures subject to nonuniform tension. A structure member has obtained the operation damage generation by corrosion and other causes.

Liquid Wall Chambers

Energy Technology Data Exchange (ETDEWEB)

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.

Molecular dynamics study on the effect of boundary heating rate on the phase change characteristics of thin film liquid

Energy Technology Data Exchange (ETDEWEB)

Hasan, Mohammad Nasim, E-mail: nasim@me.buet.ac.bd.com; Morshed, A. K. M. Monjur, E-mail: shavik@me.buet.ac.bd.com; Rabbi, Kazi Fazle, E-mail: rabbi35.me10@gmail.com; Haque, Mominul, E-mail: mominulmarup@gmail.com [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 (Bangladesh)

2016-07-12

In this study, theoretical investigation of thin film liquid phase change phenomena under different boundary heating rates has been conducted with the help of molecular dynamics simulation. To do this, the case of argon boiling over a platinum surface has been considered. The study has been conducted to get a better understanding of the nano-scale physics of evaporation/boiling for a three phase system with particular emphasis on the effect of boundary heating rate. The simulation domain consisted of liquid and vapor argon atoms placed over a platinum wall. Initially the whole system was brought to an equilibrium state at 90 K with the help of equilibrium molecular dynamics and then the temperature of the bottom wall was increased to a higher temperature (250 K/130 K) over a finite heating period. Depending on the heating period, the boundary heating rate has been varied in the range of 1600×10{sup 9} K/s to 8×10{sup 9} K/s. The variations of argon region temperature, pressure, net evaporation number with respect to time under different boundary heating rates have been determined and discussed. The heat fluxes normal to platinum wall for different cases were also calculated and compared with theoretical upper limit of maximum possible heat transfer to elucidate the effect of boundary heating rate.

A Comparative Study of Additively Manufactured Thin Wall and Block Structure with Al-6.3%Cu Alloy Using Cold Metal Transfer Process

Directory of Open Access Journals (Sweden)

Baoqiang Cong

2017-03-01

Full Text Available In order to build a better understanding of the relationship between depositing mode and porosity, microstructure, and properties in wire + arc additive manufacturing (WAAM 2319-Al components, several Al-6.3%Cu deposits were produced by WAAM technique with cold metal transfer (CMT variants, pulsed CMT (CMT-P and advanced CMT (CMT-ADV. Thin walls and blocks were selected as the depositing paths to make WAAM samples. Porosity, microstructure and micro hardness of these WAAM samples were investigated. Compared with CMT-P and thin wall mode, CMT-ADV and block process can effectively reduce the pores in WAAM aluminum alloy. The microstructure varied with different depositing paths and CMT variants. The micro hardness value of thin wall samples was around 75 HV from the bottom to the middle, and gradually decreased toward the top. Meanwhile, the micro hardness value ranged around 72–77 HV, and varied periodically in block samples. The variation in micro hardness is consistent with standard microstructure characteristics.

Diffusively cooled thin-sheath high-repetition-rate TEA and TEMA lasers

Science.gov (United States)

Yatsiv, Shaul; Gabay, Amnon; Sintov, Yoav

1993-05-01

Transverse electric atmospheric (TEA), or multi atmospheric (TEMA) lasers deliver intense short laser pulses of considerable energies. Recurrent high repetition rate pulse trains afford substantial average power levels. In a high rep-rate operation the gas flows across the cavity and is externally cooled to maintain a reasonably low temperature. The gas flow gear and heat exchanger are bulky and costly. In this work we present a repetitively pulsed TEA or TEMA laser that combines energy and peak power features in an individual pulse with the substantial average power levels of a pulse train in a thin layer of gas. Excess heat is disposed of, by conduction through the gas, to cooled enclosing walls. The gas does not flow. The method applies to vibrational transition molecular lasers in the infrared, where elevated temperatures are deleterious to the laser operation. The gist of the method draws on the law that heat conductivity in gases does not depend on their pressure. The fact lends unique operational flexibility and compactness, desirable for industrial and research purposes.

Thin-Walled CFST Columns for Enhancing Seismic Collapse Performance of High-Rise Steel Frames

Directory of Open Access Journals (Sweden)

Yongtao Bai

2017-01-01

Full Text Available This paper numerically studied the collapse capacity of high-rise steel moment-resisting frames (SMRFs using various width-to-thickness members subjected to successive earthquakes. It was found that the long-period component of earthquakes obviously correlates with the first-mode period of high-rises controlled by the total number of stories. A higher building tends to produce more significant component deterioration to enlarge the maximum story drift angle at lower stories. The width-to-thickness ratio of beam and column components overtly affects the collapse capacity when the plastic deformation extensively develops. The ratio of residual to maximum story drift angle is significantly sensitive to the collapse capacity of various building models. A thin-walled concrete filled steel tubular (CFST column is proposed as one efficient alternative to enhance the overall stiffness and deformation capacity of the high-rise SMRFs with fragile collapse performance. With the equivalent flexural stiffness, CFST-MRF buildings with thin-walled members demonstrate higher capacity to avoid collapse, and the greater collapse margin indicates that CFST-MRFs are a reasonable system for high-rises in seismic prone regions.

Nonlinear mechanics of thin-walled structures asymptotics, direct approach and numerical analysis

CERN Document Server

Vetyukov, Yury

2014-01-01

This book presents a hybrid approach to the mechanics of thin bodies. Classical theories of rods, plates and shells with constrained shear are based on asymptotic splitting of the equations and boundary conditions of three-dimensional elasticity. The asymptotic solutions become accurate as the thickness decreases, and the three-dimensional fields of stresses and displacements can be determined. The analysis includes practically important effects of electromechanical coupling and material inhomogeneity. The extension to the geometrically nonlinear range uses the direct approach based on the principle of virtual work. Vibrations and buckling of pre-stressed structures are studied with the help of linearized incremental formulations, and direct tensor calculus rounds out the list of analytical techniques used throughout the book. A novel theory of thin-walled rods of open profile is subsequently developed from the models of rods and shells, and traditionally applied equations are proven to be asymptotically exa...

Development of carbon steel with superior resistance to wall thinning and fracture for nuclear piping system

International Nuclear Information System (INIS)

Rhee, Chang Kyu; Lee, Min Ku; Park, Jin Ju

2010-07-01

Carbon steel is usually used for piping for secondary coolant system in nuclear power plant because of low cost and good machinability. However, it is generally reported that carbon steel was failed catastrophically because of its low resistance to wall thinning and fracture toughness. Especially, flow accelerated corrosion (FAC) is one of main problems of the wall thinning of piping in the nuclear power plant. Therefore, in this project, fabrication technology of new advanced carbon steel materials modified by dispersion of nano-carbide ceramics into the matrix is developed first in order to improve the resistance to wall thinning and fracture toughness drastically compared to the conventional one. In order to get highly wettable fine TiC ceramic particles into molten metal, the micro-sized TiC particles were first mechanically milled by Fe (MMed TiC/Fe) in a high energy ball mill machine in Ar gas atmosphere, and then mixed with surfactant metal elements (Sn, Cr, Ni) to obtain better wettability, as this lowered surface tension of the carbon steel melt. According to microscopic images revealed that an addition of MMed TiC/Fe-surfactant mixed powders favorably disperses the fine TiC particles in the carbon steel matrix. It was also found that the grain size refinement of the cast matrix is achieved remarkably when fine TiC particles were added due to the fact that they act as nucleation sites during the solidification process. As a results, a cast carbon steel dispersed with fine TiC particles shows improved mechanical properties such as hardness, tensile strength and cavitation resistance compared to that of without particles. However, the slight decrease of toughness was found

Insulin pen needles: effects of extra-thin wall needle technology on preference, confidence, and other patient ratings.

Science.gov (United States)

Aronson, Ronnie; Gibney, Michael A; Oza, Kunjal; Bérubé, Julie; Kassler-Taub, Kenneth; Hirsch, Laurence

2013-07-01

Pen needles (PNs) are essential for insulin injections using pen devices. PN characteristics affect patients' injection experience. The goal of this study was to evaluate the impact of a new extra-thin wall (XTW) PN versus usual PNs on overall patient preference, ease of injection, perceived time to complete the full dose, thumb button force to deliver the injection, and dose delivery confidence in individuals with diabetes mellitus (DM). Subjects injected insulin with the KwikPen(TM) (Eli Lilly and Company, Indianapolis, Indiana), SoloSTAR(®) (sanofi-aventis U.S. LLC, Bridgewater, New Jersey), and FlexPen(®) (Novo Nordisk A/S, Bagsvaerd, Denmark) insulin pens, and included some with impaired hand dexterity. We first performed quantitative testing of XTW and comparable PNs with the 3 insulin pens for thumb force, flow rate, and time to deliver medication. A prospective, randomized, 2-period, open-label, crossover trial was then conducted in patients aged 35 to 80 years with type 1 or type 2 DM who injected insulin by pen for ≥2 months, with at least 1 daily dose ≥10 U. Patients who used 4- to 8-mm length PNs with 31- to 32-G diameter were randomly assigned to use their current PN or the same/similar size XTW PN at home for ~1 week and the other PN the second week. They completed several comparative 150-mm visual analog scales and direct questions at the end of period 2. XTW PNs had statistically significant better performance for each studied PN characteristic (thumb force, flow, and time to deliver medication) for all pens combined and each individual pen brand (all, P ≤ 0.05). Of 216 patients randomized to study groups (80, SoloSTAR; 77, FlexPen; 59, KwikPen), 209 completed both periods; 198 were evaluable. Baseline characteristics revealed a mean (SD) age of 60.8 (9.3) years, insulin pen use duration of 4.3 (4.1) years, and mean total daily dose of 75.1 (52.3) U (range, 10-420 U). Approximately 50% of patients were female; 81.5% were white and 14.8% were

Assessment of thin-walled cladding tube mechanical properties by segmented expanding Mandrel test

International Nuclear Information System (INIS)

Nilsson, Karl-Fredrik

2015-01-01

This paper presents the principles of the segmented expanding mandrel test for thin-walled cladding tubes, which can be used as a basic material characterisation test to determine stress-strain curves and ductility or as a test to simulate mechanical pellet-cladding interaction. The paper discusses the strengths and weaknesses of the test method and it illustrates how the test can be used to simulate hydride reorientations in zirconium claddings and quantify how hydride reorientation affects ductility. (authors)

Modelling of Eutectic Saturation Influence on Microstructure in Thin Wall Ductile Iron Casting Using Cellular Automata

Directory of Open Access Journals (Sweden)

Burbelko A.A.

2012-12-01

Full Text Available The mathematical model of the globular eutectic solidification in 2D was designed. Proposed model is based on the Cellular Automaton Finite Differences (CA-FD calculation method. Model has been used for studies of the primary austenite and of globular eutectic grains growth during the ductile iron solidification in the thin wall casting. Model takes into account, among other things, non-uniform temperature distribution in the casting wall cross-section, kinetics of the austenite and graphite grains nucleation, and non-equilibrium nature of the interphase boundary migration. Calculation of eutectic saturation influence (Sc = 0.9 - 1.1 on microstructure (austenite and graphite fraction, density of austenite and graphite grains and temperature curves in 2 mm wall ductile iron casting has been done.

An Applied Method for Predicting the Load-Carrying Capacity in Compression of Thin-Wall Composite Structures with Impact Damage

Science.gov (United States)

Mitrofanov, O.; Pavelko, I.; Varickis, S.; Vagele, A.

2018-03-01

The necessity for considering both strength criteria and postbuckling effects in calculating the load-carrying capacity in compression of thin-wall composite structures with impact damage is substantiated. An original applied method ensuring solution of these problems with an accuracy sufficient for practical design tasks is developed. The main advantage of the method is its applicability in terms of computing resources and the set of initial data required. The results of application of the method to solution of the problem of compression of fragments of thin-wall honeycomb panel damaged by impacts of various energies are presented. After a comparison of calculation results with experimental data, a working algorithm for calculating the reduction in the load-carrying capacity of a composite object with impact damage is adopted.

A single-walled carbon nanotube thin film-based pH-sensing microfluidic chip.

Science.gov (United States)

Li, Cheng Ai; Han, Kwi Nam; Pham, Xuan-Hung; Seong, Gi Hun

2014-04-21

A novel microfluidic pH-sensing chip was developed based on pH-sensitive single-walled carbon nanotubes (SWCNTs). In this study, the SWCNT thin film acted both as an electrode and a pH-sensitive membrane. The potentiometric pH response was observed by electronic structure changes in the semiconducting SWCNTs in response to the pH level. In a microfluidic chip consisting of a SWCNT pH-sensing working electrode and an Ag/AgCl reference electrode, the calibration plot exhibited promising pH-sensing performance with an ideal Nernstian response of 59.71 mV pH(-1) between pH 3 and 11 (standard deviation of the sensitivity is 1.5 mV pH(-1), R(2) = 0.985). Moreover, the SWCNT electrode in the microfluidic device showed no significant variation at any pH value in the range of the flow rate between 0.1 and 15 μl min(-1). The selectivity coefficients of the SWCNT electrode revealed good selectivity against common interfering ions.

THIN-WALLED CROSS SECTION SHAPE INFLUENCE ON STEEL MEMBER RESISTANCE

Directory of Open Access Journals (Sweden)

Elżbieta Urbańska-Galewska

2016-03-01

Full Text Available This work describes why trending thin-walled technology is achieving popularity in steel construction sector. A purpose of this article is to present the influence of the cold-formed element cross-section shape on an axial compression and a bending moment resistance. The authors have considered four different shapes assuming constant section area and thickness. Calculations were based on three different steel grades taking into account local, distortional and overall buckling. The results are presented in a tabular and a graphical way and clearly confirm that cross-section forming distinctly impact the cold-formed member resistance. The authors choose these cross-sections that work better in compression state and the other (those slender and high that function more efficiently are subjected to bending.

Estimation of collapse moment for the wall-thinned pipe bends using fuzzy model identification

International Nuclear Information System (INIS)

Na, Man Gyun; Kim, Jin Weon; Hwang, In Joon

2006-01-01

In this work, the collapse moment due to wall-thinned defects is estimated through fuzzy model identification. A subtractive clustering method is used as the basis of a fast and robust algorithm for identifying the fuzzy model. The fuzzy model is optimized by a genetic algorithm combined with a least squares method. The developed fuzzy model has been applied to the numerical data obtained from the finite element analysis. Principal component analysis is used to preprocess the input signals into the fuzzy model to reduce the sensitivity to the input change and the fuzzy model are trained by using the data set prepared for training (training data) and verified by using another data set different (independent) from the training data. Also, three fuzzy models are trained, respectively, for three data sets divided into the three classes of extrados, intrados, and crown defects, which is because they have different characteristics. The relative root mean square (RMS) errors of the estimated collapse moment are 0.5397% for the training data and 0.8673% for the test data. It is known from this result that the fuzzy models are sufficiently accurate to be used in the integrity evaluation of wall-thinned pipe bends and elbows

Thin-walled beam tubes for the SIS. Construction and manufacturing

International Nuclear Information System (INIS)

Malwitz, E.

1985-06-01

The vacuum system of the SIS consists essentially of torus-shaped vacuum chamber with an annulus-circumference of 216 m which is composed by several beam-tube and chamber elements. In order to reach the desired final pressure of -11 mbar (5 . 10 -9 Pa) a heating of the whole vacuum system to 300 0 C is required. The beam tubes within magnets have regularly an elliptic tube cross section. Within bending magnets the beam tubes are curved in a plane through the large ellipse axis with a bending radius of 10 m. During the development work for the beam tubes within magnets to construction variants were studied until construction maturity. Generally thin-walled beam tubes with elliptic tube cross section are fabricated similarly to spring bellows as corrugated tubes. In this report however beam tubes with elliptic tube cross section are discussed the tube walls of which are smooth and stabilized against the atmospheric pressure by hard-soldered ribs. The report reproduces mainly the most important know how respectively serves as instruction for new constructions. Such beam tubes are planned for the dipole magnets and the quadrupole group consisting of two long quadrupoles, a short quadrupole, and a sextupole. (orig./HSI) [de

Numerical simulation of instability behaviour of thin-walled frames with flexible connections

International Nuclear Information System (INIS)

Turkalj, G.; Brnic, J.; Vizentin, G.; Lanc, D.

2009-01-01

A one-dimensional finite element formulation for numerical simulation of instability behaviour of thin-walled frames containing flexible connections is presented. Stiffness matrices of a conventional 14-degree of freedom beam element are derived by applying the linearized virtual work principle and Vlasov's assumption. The structural material is assumed to be homogeneous, isotropic and linear-elastic. Flexible connection behaviour and different warping deformation conditions are introduced into the numerical model by modifying stiffness matrices of a conventional beam element. For that purpose a special transformation matrix is derived. The effectiveness of the numerical algorithm discussed is validated through the test problem

Aerodynamics of a thin airfoil flying over and in proximity to a wavy-wall surface. ; Lifting surface theory

Energy Technology Data Exchange (ETDEWEB)

Ando, S [Nagoya University, Nagoya (Japan); Ichikawa, M [Government Industrial Research Institute, Nagoya, Nagoya (Japan)

1991-05-04

Aerodynamic characteristics of a thin airfoil flying over and in proximity to a wavy-wall surface such as uneven ground or water surface were analyzed two-dimensionally by lifting surface theory in the simplest fundamental case only. The theoretical equation was simplified assuming that flow is inviscid and incompressible, all disturbances are sufficiently small, the wall surface is sinusoidal and rigid, and the wall moves in the same direction as free stream but with a constant velocity different from that of the stream. The equation was verified in the case where an airfoil with a constant angle-of-attack flies over a flat ground surface, and calculations were made with a set of important parameters such as mean airfoil height from the wall, wave length of the wall surface and the wall velocity. The whole effect of wavy wall proximity was divided into the first and second-order ground effects. The first one was just Kemp{prime}s upwash problem, and the second one was revealed through the present study which becomes significant for lower airfoil heights. 18 refs., 5 figs.

Manufacture of thin-walled clad tubes by pressure welding of roll bonded sheets

Science.gov (United States)

Schmidt, Hans Christian; Grydin, Olexandr; Stolbchenko, Mykhailo; Homberg, Werner; Schaper, Mirko

2017-10-01

Clad tubes are commonly manufactured by fusion welding of roll bonded metal sheets or, mechanically, by hydroforming. In this work, a new approach towards the manufacture of thin-walled tubes with an outer diameter to wall thickness ratio of about 12 is investigated, involving the pressure welding of hot roll bonded aluminium-steel strips. By preparing non-welded edges during the roll bonding process, the strips can be zip-folded and (cold) pressure welded together. This process routine could be used to manufacture clad tubes in a continuous process. In order to investigate the process, sample tube sections with a wall thickness of 2.1 mm were manufactured by U-and O-bending from hot roll bonded aluminium-stainless steel strips. The forming and welding were carried out in a temperature range between RT and 400°C. It was found that, with the given geometry, a pressure weld is established at temperatures starting above 100°C. The tensile tests yield a maximum bond strength at 340°C. Micrograph images show a consistent weld of the aluminium layer over the whole tube section.

Non-linear analysis of the behaviour of a thin and squat reinforced concrete wall on a seismic table

International Nuclear Information System (INIS)

Mazars, J.; Ghavamian, S.; Ile, N.; Reynouard, J.M.

1998-01-01

This work concerns the modeling and analysis of the seismic behaviour of a thin reinforced concrete wall using an experiment performed by the NUPEC (Nuclear Power Engineering Corporation) Japanese organisation with the Tadotsu seismic table. The wall with a height/width ratio close to 1, has its extremities stiffened and its base embedded. The wall, loaded on its top with a 122 t weight, is submitted to several seismic levels up to its collapse. A non-linear seismic analysis and different 2-D and 3-D finite elements modeling were used to simulate the behaviour of the structure submitted to a strong dynamic shear. The results presented in this paper belong to the ''Seismic Shear Wall Standard Problem'' benchmark jointly organized the NUPEC and OECD organizations. (J.S.)

Wall thinning inspection technique for large-diameter piping using guided wave

International Nuclear Information System (INIS)

Miki, Masahiro; Nagashima, Yoshiaki; Endou, Masao; Kodaira, Kojiro; Maniwa, Kazuhiko

2009-01-01

Guided wave inspection technique is effective for detecting defects like corrosion in piping, because it can perform long range inspection. It is possible to expect this inspection as a method that leads to the decrease of the inspection process and its cost, because the incidental work can be reduced. Especially, the contraction effect of the inspection work is extensive in large-diameter piping inspection. In this paper, we introduce the guided wave inspection system to large-diameter piping. The feature is a guided wave sensor that can freely transform according to the curvature of inspection object, and portable inspection equipment. We discuss the result of detection examination for artificial wall-thinning in large-diameter piping using this system. (author)

On designing of the thin-walled bars in the light of theory and experiments

International Nuclear Information System (INIS)

Obrebski, J.B.; Urbaniak, Z.; El-Awady, M.E.

1992-01-01

The paper presents some data and conclusions derived from the experiments and computations concerning the influence of constructional details and solutions on strength of straight thin-walled bars. The attention specially is paid to: the different instability phenomena i.e. local and global for the bar with any cross-section, the capacity of the bar by bending-torsional loading, the theory of 2d approximation, and comparisons of theoretical problems mentioned above with the proper experiments. (orig.)

Flux mapping at 77 K and local measurement at lower temperature of thin-wall YBaCuO single-domain samples oxygenated under high pressure

Energy Technology Data Exchange (ETDEWEB)

Chaud, X., E-mail: Xavier.chaud@grenoble.cnrs.f [CRETA, CNRS, 25, Avenue des Martyrs, 38042 Grenoble Cedex 9 (France); Noudem, J. [CRISMAT/ENSICAEN, CNRS, 6 bd Marechal Juin, 14050 Caen (France); Prikhna, T.; Savchuk, Y. [ISM, National Acad. of Sciences of Ukraine, 2 Avtozavodskaya Street, Kiev, 04074 (Ukraine); Haanappel, E. [LNCMP, UMR 5147, 143 avenue de Rangueil, 31400 Toulouse (France); Diko, P. [IEP, Slovak Acad. of Sciences, Watsonova 47, 043 53, Kosice (Slovakia); Zhang, C.P. [SMRC, NIN, 96 Weiyang Road, Xi' an 710016 (China)

2009-10-15

YBCO single-domain samples are suitable for the production of high trapped fields in the range 20-77 K using a cryocooler or liquid nitrogen. But the oxygenation process required to actually transform the single domains into superconductors induces an extensive crack network that is limiting the material performances. Thin-wall geometry has been introduced to reduce the diffusion paths and to enable a progressive oxygenation strategy. As a consequence cracks are drastically reduced. In addition the use of a high oxygen pressure (16 MPa) speeds up further the process by displacing the oxygen-temperature equilibrium towards the higher temperature of the phase diagram. The advantage of thin-wall geometry is that such an annealing can be applied directly to a much larger sample. Remarkable results are obtained without any doping by the combination of thin walls and oxygen high pressure. While classical plain samples yield 300-400 mT, a trapped field of 840 mT has been measured at 77 K on a 16 mm diameter Y123 thin-wall single-domain sample with an annealing time as short as 3 days. Local measurements with a fixed Hall probe on top of the sample were performed at lower temperature after magnetization either in a static field or in a pulse field. The trapped field is significantly higher at lower temperature. Cryocoolers become the key to compromise between performances and cryogenic cost around 40 K.

Development of evaluation method on flow-induced vibration and corrosion of components in two-phase flow by coupled analysis. 5. Evaluation of wall thinning rate with the coupled model of static electrochemical analysis and dynamic double oxide layer analysis

International Nuclear Information System (INIS)

Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Uehara, Yasushi

2008-01-01

Wall thinning rates due to FAC were calculated with the coupled model of static electrochemical analysis and dynamic double oxide layer analysis at the identified danger zone. Anodic and cathodic current densities and ECPs were calculated with the static electrochemistry model and ferrous ion release rate determined by the anodic current density was used as input for the dynamic double oxide layer model. Thickness of oxide film and its characteristics determined by the dynamic double oxide layer model were used for the electrochemistry model to determine the resistances of cathodic current from the bulk to the surface and anodic current from the surface to the bulk. Two models were coupled to determine local corrosion rate and ECP for various corrosive conditions. The calculated results of the coupled models had good agreement with the measured ones. (author)

Complete Status Report Documenting Development of Friction Stir Welding for Joining Thin Wall Tubing of ODS Alloys

Energy Technology Data Exchange (ETDEWEB)

Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bunn, Jeffrey R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-08-01

The development of friction stir welding (FSW) for joining thin sections of the advanced oxide dispersion strengthened (ODS) 14YWT ferritic alloy was initiated in Fuel Cycle Research and Development (FCRD), now the Nuclear Technology Research and Development (NTRD), in 2015. The first FSW experiment was conducted in late FY15 and successfully produced a bead-on-plate stir zone (SZ) on a 1 mm thick plate of 14YWT (SM13 heat). The goal of this research task is to ultimately demonstrate that FSW is a feasible method for joining thin wall (0.5 mm thick) tubing of 14YWT.

Structural Properties of EB-Welded AlSi10Mg Thin-Walled Pressure Vessels Produced by AM-SLM Technology

Science.gov (United States)

Nahmany, Moshe; Stern, Adin; Aghion, Eli; Frage, Nachum

2017-10-01

Additive manufacturing of metals by selective laser melting (AM-SLM) is hampered by significant limitations in product size due to the limited dimensions of printing trays. Electron beam welding (EBW) is a well-established process that results in relatively minor metallurgical modifications in workpieces due to the ability of EBW to pass high-density energy to the related substance. The present study aims to evaluate structural properties of EB-welded AlSi10Mg thin-walled pressure vessels produced from components prepared by SLM technology. Following the EB welding process, leak and burst tests were conducted, as was fractography analysis. The welded vessels showed an acceptable holding pressure of 30 MPa, with a reasonable residual deformation up to 2.3% and a leak rate better than 1 × 10-8 std-cc s-1 helium. The failures that occurred under longitudinal stresses reflected the presence of two weak locations in the vessels, i.e., the welded joint region and the transition zone between the vessel base and wall. Fractographic analysis of the fracture surfaces of broken vessels displayed the ductile mode of the rupture, with dimples of various sizes, depending on the failure location.

Fatigue life assessment of thin-walled welded joints under non-proportional load-time histories by the shear stress rate integral approach

Directory of Open Access Journals (Sweden)

A. Bolchoun

2016-10-01

Full Text Available Fatigue life tests under constant and variable amplitude loadings were performed on the tube-tube thin-walled welded specimens made of magnesium (AZ31 and AZ61 alloys. The tests included pure axial, pure torsional and combined in-phase and out-of-phase loadings with the load ratio  RR " ", " " 1  . For the tests with variable amplitude loads a Gaußdistributed loading spectrum with S L 4 5 10  cycles was used. Since magnesium welds show a fatigue life reduction under out-of-phase loads, a stress-based method, which takes this behavior into account, is proposed. The out-of-phase loading results in rotating shear stress vectors in the section planes, which are not orthogonal to the surface. This fact is used in order to provide an out-of-phase measure of the load. This measure is computed as an area covered by the shear stress vectors in all planes over a certain time interval, its computation involves the shear stress and the shear stress rate vectors in the individual planes. Fatigue life evaluation for the variable amplitudes loadings is performed using the Palmgren-Miner linear damage accumulation, whereas the total damage of every cycle is split up into two components: the amplitude component and the out-of-phase component. In order to compute the two components a modification of the rainflow counting method, which keeps track of the time intervals, where the cycles occur, must be used. The proposed method also takes into account different slopes of the pure axial and the pure torsional Wöhler-line by means of a Wöhler-line interpolation for combined loadings

Proposal of failure criterion applicable to finite element analysis results for wall-thinned pipes under bending load

Energy Technology Data Exchange (ETDEWEB)

Meshii, Toshiyuki, E-mail: meshii@u-fukui.ac.jp [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui (Japan); Ito, Yoshiaki [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui (Japan)

2012-01-15

Highlights: Black-Right-Pointing-Pointer Limit bending load (LBL) of wall-thinned pipe by large strain FEA was considered. Black-Right-Pointing-Pointer Net section yield load had sufficient margin to LBL. Black-Right-Pointing-Pointer LBL for collapse was the load when volume with nominal thickness yielded. Black-Right-Pointing-Pointer LBL for cracking was the load when flawed section stress exceeded tensile strength. Black-Right-Pointing-Pointer Failure criterion considering above was named Domain Collapse Criterion. - Abstract: In this work, a failure criterion applicable to large strain Finite Element Analysis (FEA) results was proposed in order to predict both the fracture mode (collapse or cracking) and the limit bending load of wall-thinned straight pipes. This work was motivated from the recent experimental results of ; that is, fracture mode is not always collapse, and the fracture mode affects the limit bending load. The key finding in comparing their test results and a detailed large strain FEA results was that the Mises stress distribution at the limit bending load of a flawed cylinder was similar to that of a flawless cylinder; specifically, in case of collapse, the Mises stress exceeded the true yield stress of a material for the whole 'volume' of a cylinder with a nominal wall thickness. Based on this finding, a failure criterion applicable to large strain FEA results of wall-thinned straight pipes under a bending load that can predict both fracture mode and limit bending load was proposed and was named the Domain Collapse Criterion (DCC). DCC predicts the limit bending load as the lower value of either the M{sub c}{sup FEA}, which is the load at which the Mises stress exceeds the true yield strength of a straight pipe for the whole 'volume' with a nominal wall thickness (fracture mode: collapse), or the M{sub c}{sup FEAb}, which is the load at which the Mises stress in a section of the flaw ligament exceeds the true tensile stress

Vibration characteristics of two-stage planetary transmission system with thin-walled ring gear on elastic supports

Science.gov (United States)

Li, JianYing; Hu, QingChun; Zong, ChangFu; Zhu, TianJun; Zhang, ZeXing

2018-03-01

A dual-clutch and dual-speed planetary gears mechanism of a hybrid car coupled-system is taken as research subject, in which the ring gear of planet set II is a thin-walled structure and the clutch friction plates of planet set II are used as its elastic supports. Based on the lumped parameter-rigid elastic coupled dynamic model of two-stage planetary transmission system with thin-walled ring gear on elastic supports, the motion differential equations are established and the dynamic responses are solved by the Runge-Kutta method considering each stage internal and external time-varying mesh stiffness. The vibration displacements of each stage ring gear have been affected differently in time-domain, the translational vibration displacement of the ring gear of planet set I are obviously more than the torsional vibration displacement, but it is opposite for the ring gear of planet set II; The translational and torsional vibration responses of each stage ring gear arrive the peak in low-frequency. The analysis results of this paper can enrich the theoretical research of multistage planetary transmission and provide guidance for dynamic design.

Design of welding parameters for laser welding of thin-walled stainless steel tubes using numerical simulation

Science.gov (United States)

Nagy, M.; Behúlová, M.

2017-11-01

Nowadays, the laser technology is used in a wide spectrum of applications, especially in engineering, electronics, medicine, automotive, aeronautic or military industries. In the field of mechanical engineering, the laser technology reaches the biggest increase in the automotive industry, mainly due to the introduction of automation utilizing 5-axial movements. Modelling and numerical simulation of laser welding processes has been exploited with many advantages for the investigation of physical principles and complex phenomena connected with this joining technology. The paper is focused on the application of numerical simulation to the design of welding parameters for the circumferential laser welding of thin-walled exhaust pipes from theAISI 304 steel for automotive industry. Using the developed and experimentally verified simulation model for laser welding of tubes, the influence of welding parameters including the laser velocity from 30 mm.s-1 to 60 mm.s-1 and the laser power from 500 W to 1200 W on the temperature fields and dimensions of fusion zone was investigated using the program code ANSYS. Based on obtained results, the welding schedule for the laser beam welding of thin-walled tubes from the AISI 304 steel was suggested.

Optimization process for thin-walled high performance concrete sandwich panels

DEFF Research Database (Denmark)

Hodicky, Kamil; Hulin, Thomas; Schmidt, Jacob Wittrup

2014-01-01

with the specifications of the design constrains and variables. The tool integrates the processes of HPCSP design, quantity take-off and cost estimation into a single system that would provide different costs for different HPCSP designs. The proposed multi-objective optimisation scheme results into derivation of basic......A Nearly zero energy buildings are to become a requirement as part of the European energy policy. There are many ways of designing nearly zero energy buildings, but there is a lack of knowledge on optimization processes in the sense of structurally and thermally efficient design with an optimal...... economical solution. The present paper aims to provide multi-objective optimisation procedure addressed to structural precast thin-walled High Performance Concrete Sandwich Panels (HPCSP). The research aim is concerned with developing a tool that considers the cost of HPCSP materials along...

Thermal modeling and analysis of thin-walled structures in micro milling

Science.gov (United States)

Zhang, J. F.; Ma, Y. H.; Feng, C.; Tang, W.; Wang, S.

2017-11-01

The numerical analytical model has been developed to predict the thermal effect with respect to thin walled structures by micro-milling. In order to investigate the temperature distribution around micro-edge of cutter, it is necessary to considering the friction power, the shearing power, the shear area between the tool micro-edge and materials. Due to the micro-cutting area is more difficult to be measured accurately, the minimum chip thickness as one of critical factors is also introduced. Finite element-based simulation was employed by the Advantedge, which was determined from the machining of Ti-6Al-4V over a range of the uncut chip thicknesses. Results from the proposed model have been successfully accounted for the effects of thermal softening for material.

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

International Nuclear Information System (INIS)

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

2014-01-01

We investigated quantum confinement effects in Bi anti-dot thin films grown on anodized aluminium oxide templates. The pore wall widths (w Bi ) and thickness (t) of the films were tailored to have values longer or shorter than Fermi wavelength of Bi (λ F  = ∼40 nm). Magnetoresistance measurements revealed a well-defined weak antilocalization effect below 10 K. Coherence lengths (L 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 Bi and t smaller than λ F showed low dimensional electronic behavior at low temperatures where L ϕ (T) exceed w Bi or t

Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

International Nuclear Information System (INIS)

Zsirka, Balázs; Horváth, Erzsébet; Szabó, Péter; Juzsakova, Tatjána; Szilágyi, Róbert K.; Fertig, Dávid; Makó, Éva; Varga, Tamás

2017-01-01

Highlights: • Halloysite intercalation/delamination. • Thin-walled nanoscroll preparation. • Oxidative surface cleaning with H_2O_2 and heating. • X-ray diffraction, TEM, N_2 adsorption, TG/DTG and FT-IR/ATR measurements. • Nanoscroll rearrangement, periodicity along the crystallographic ‘c’-axis. - Abstract: Surface modification of the halloysite-10 Å mineral with tubular morphology can be achieved by slightly modified procedures developed for the delamination of kaolinite minerals. The resulting delaminated halloysite nanoparticles have unexpected surface/morphological properties that display, new potentials in catalyst development. In this work, a four-step intercalation/delamination procedure is described for the preparation of thin-walled nanoscrolls from the multi-layered hydrated halloysite mineral that consists of (1) intercalation of halloysite with potassium acetate, (2) replacement intercalation with ethylene glycol, (3) replacement intercalation with hexylamine, and (4) delamination with toluene. The intercalation steps were followed by X-ray diffraction, transmission electron microscopy, N_2 adsorption-desorption, thermogravimetry, and infrared spectroscopy. Delamination eliminated the crystalline order and the crystallite size along the ‘c’-axis, increased the specific surface area, greatly decreased the thickness of the mineral tubes to a monolayer, and shifted the pore diameter toward the micropore region. Unexpectedly, the removal of residual organics from intercalation steps adsorbed at the nanoscroll surface with a peroxide treatment resulted in partial recovery of crystallinity and increase of crystallite size along the ‘c’-crystal direction. The d(001) value showed a diffuse pattern at 7.4–7.7 Å due to the rearrangement of the thin-walled nanoscrolls toward the initial tubular morphology of the dehydrated halloysite-7 Å mineral.

Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

Energy Technology Data Exchange (ETDEWEB)

Zsirka, Balázs, E-mail: zsirkab@almos.vein.hu [University of Pannonia, Institute of Environmental Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Horváth, Erzsébet, E-mail: erzsebet.horvath@gmail.com [University of Pannonia, Institute of Environmental Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Szabó, Péter, E-mail: xysma@msn.com [University of Pannonia, Department of Analytical Chemistry, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Juzsakova, Tatjána, E-mail: yuzhakova@almos.uni-pannon.hu [University of Pannonia, Institute of Environmental Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Szilágyi, Róbert K., E-mail: szilagyi@montana.edu [Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717 (United States); Fertig, Dávid, E-mail: fertig.david92@gmail.com [University of Pannonia, Department of Analytical Chemistry, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Makó, Éva, E-mail: makoe@almos.vein.hu [University of Pannonia, Institute of Materials Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Varga, Tamás, E-mail: vtamas@chem.u-szeged.hu [University of Szeged, Department of Applied and Environmental Chemistry, Rerrich B. tér 1., Szeged H-6720 Hungary (Hungary); and others

2017-03-31

Highlights: • Halloysite intercalation/delamination. • Thin-walled nanoscroll preparation. • Oxidative surface cleaning with H{sub 2}O{sub 2} and heating. • X-ray diffraction, TEM, N{sub 2} adsorption, TG/DTG and FT-IR/ATR measurements. • Nanoscroll rearrangement, periodicity along the crystallographic ‘c’-axis. - Abstract: Surface modification of the halloysite-10 Å mineral with tubular morphology can be achieved by slightly modified procedures developed for the delamination of kaolinite minerals. The resulting delaminated halloysite nanoparticles have unexpected surface/morphological properties that display, new potentials in catalyst development. In this work, a four-step intercalation/delamination procedure is described for the preparation of thin-walled nanoscrolls from the multi-layered hydrated halloysite mineral that consists of (1) intercalation of halloysite with potassium acetate, (2) replacement intercalation with ethylene glycol, (3) replacement intercalation with hexylamine, and (4) delamination with toluene. The intercalation steps were followed by X-ray diffraction, transmission electron microscopy, N{sub 2} adsorption-desorption, thermogravimetry, and infrared spectroscopy. Delamination eliminated the crystalline order and the crystallite size along the ‘c’-axis, increased the specific surface area, greatly decreased the thickness of the mineral tubes to a monolayer, and shifted the pore diameter toward the micropore region. Unexpectedly, the removal of residual organics from intercalation steps adsorbed at the nanoscroll surface with a peroxide treatment resulted in partial recovery of crystallinity and increase of crystallite size along the ‘c’-crystal direction. The d(001) value showed a diffuse pattern at 7.4–7.7 Å due to the rearrangement of the thin-walled nanoscrolls toward the initial tubular morphology of the dehydrated halloysite-7 Å mineral.

Dynamical analysis of electrochemical wall shear rate measurements

NARCIS (Netherlands)

Steenhoven, van A.A.; Beucken, van den F.J.H.M.

1991-01-01

The performance of a circular electrochemical wall shear rate probe under unsteady flow conditions is analysed through a combined ezxperimental, numerical and analytical approach. The experiments are performed with a ferri- and ferrocyanide redox couple and compared to finite element analysis of the

A proposal on restart rule of nuclear power plants with piping having local wall thinning subjected to an earthquake. Former part. Aiming at further application

International Nuclear Information System (INIS)

Urabe, Yoshio

2011-01-01

Restart rule of nuclear power plants (NPPs) with piping having local wall thinning subjected to an earthquake was proposed taking account of local wall thinning, seismic effects and restart of NPPs with applicability of 'Guidelines for NPP Response to an Earthquake (EPRI NP-6695)' in Japan. Japan Earthquake Damage Intensity Scale (JEDIS) and Earthquake Ground Motion Level (EGML) were introduced. JEDIS was classified into four scales obtained from damage level of components and structures of NPPs subjected to an earthquake, while EGML was divided into four levels by safe shutdown earthquake ground motion (So), elastic design earthquake ground motion (Sd) and design earthquake ground motion (Ss). Combination of JEDIS and EGML formulated 4 x 4 matrix and determined detailed conditions of restart of NPPs. As a response to an earthquake, operator walk inspections and evaluation of earthquake ground motion were conducted to know the level of JEDIS. JEDIS level requested respective allowable conditions of restart of NPP, which were scale level dependent and consisted of weighted combination of damage inspection (operator walk inspections, focused inspections/tests and expanded inspections), integrity evaluation and repair/replacement. If JEDIS were assigned greater than 3 with expanded inspections, inspection of piping with local wall thinning, its integrity evaluation and repair/replacement if necessary were requested. Inspection and evaluation of piping with local wall thinning was performed based on JSME or ASME codes. Detailed work flow charts were presented. Carbon steel piping and elbow was chosen for evaluation. (T. Tanaka)

A Variable Stiffness Analysis Model for Large Complex Thin-Walled Guide Rail

Directory of Open Access Journals (Sweden)

Wang Xiaolong

2016-01-01

Full Text Available Large complex thin-walled guide rail has complicated structure and no uniform low rigidity. The traditional cutting simulations are time consuming due to huge computation especially in large workpiece. To solve these problems, a more efficient variable stiffness analysis model has been propose, which can obtain quantitative stiffness value of the machining surface. Applying simulate cutting force in sampling points using finite element analysis software ABAQUS, the single direction variable stiffness rule can be obtained. The variable stiffness matrix has been propose by analyzing multi-directions coupling variable stiffness rule. Combining with the three direction cutting force value, the reasonability of existing processing parameters can be verified and the optimized cutting parameters can be designed.

Study on flow instability for feasibility of a thin liquid film first wall

Energy Technology Data Exchange (ETDEWEB)

Okino, Fumito, E-mail: fumito.okino@iae.kyoto-u.ac.jp [Kyoto University Graduate School of Energy Science, Gokasho Uji, Kyoto (Japan); Kasada, Ryuta; Konishi, Satoshi [Kyoto University Institute of Advanced Energy, Gokasho Uji, Kyoto (Japan)

2014-10-15

Highlights: • We propose a probability of an instability wave growth on a liquid metal first wall. • Evaporated gas by the high energy flux is predicted to agitate this instability wave. • Liquid Pb-17Li with a velocity 10 m/s, the ambient gas must be below 6.2 × 10{sup 3} Pa. • This pressure corresponds to 1600 K and it is attainable under a fusion energy flux. • This probability is not yet verified so the full verifications are to be performed. - Abstract: This study proposes a probability of the evaporated gas that agitates a growing instability wave in a thin liquid film first wall. The liquid first wall was considered to be in vacuum and the effect of the ambient gas was neglected but the evaporated gas by the high energy fluxes is a probable cause of unstable wave agitation. The criterion is approximately expressed by the density ratio (Q{sub 2}) and the Weber number (We) as Q{sub 2} × We{sup 0.5} ≈ 5 × 10{sup −4}. Performed indirect experimental supported this criterion. For a case study of liquid Pb-17Li film with a velocity of 10 m/s, the evaporated gas pressure must be below 6.2 × 10{sup 3} Pa to maintain stable conditions. By recent study, this pressure is generated at 1600 K temperature and it is believed to be attainable by the energy fluxes on the first wall. This result is so far not confirmed so the full verification by experimental is to be performed.

Laminar boundary layer near the rotating end wall of a confined vortex

Science.gov (United States)

Shakespeare, W. J.; Levy, E. K.

1982-06-01

The results of an experimental and theoretical investigation of the fluid mechanics in a confined vortex are discussed with particular emphasis on behavior away from the axis of symmetry and near the end walls. The vortex is generated in a rotating cylindrical chamber with an exit opening in one end. Both end walls rotate. For the range of flow rates and swirl ratios (S between 1 and 5) of interest here, the flow field far from the end walls behaves as inviscid and irrotational; and the end wall boundary layers are thin and laminar. Measurements and calculations of tangential and radial velocity in the end wall region show the development of a secondary flow resulting in a strong velocity 'overshoot' in the radial component. Results illustrating the nature of the velocity variations on the end walls are presented; and it is shown that the mass flow rate through the end wall boundary layers, while only a small fraction of the total flow, increases with increasing swirl and with decreasing total flow rate through the chamber.

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

Energy Technology Data Exchange (ETDEWEB)

Park, Y., E-mail: youngok@chem.s.u-tokyo.ac.jp [Department of Chemistry, The University of Tokyo, Bunkyo, Tokyo 113-0033 (Japan); Hirose, Y.; Fukumura, T.; Hasegawa, T. [Department of Chemistry, The University of Tokyo, Bunkyo, Tokyo 113-0033 (Japan); Kanagawa Academy of Science and Technology (KAST), Kawasaki 213-0012 (Japan); CREST, JST, Bunkyo, Tokyo 113-0033 (Japan); Nakao, S. [Kanagawa Academy of Science and Technology (KAST), Kawasaki 213-0012 (Japan); CREST, JST, Bunkyo, Tokyo 113-0033 (Japan); Xu, J. [School of Engineering, Brown University, Providence, Rhode Island 02912 (United States)

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.

Analytical Investigation of Elastic Thin-Walled Cylinder and Truncated Cone Shell Intersection Under Internal Pressure

OpenAIRE

Zamani, J.; Soltani, B.; Aghaei, M.

2014-01-01

An elastic solution of cylinder-truncated cone shell intersection under internal pressure is presented. The edge solution theory that has been used in this study takes bending moments and shearing forces into account in the thin-walled shell of revolution element. The general solution of the cone equations is based on power series method. The effect of cone apex angle on the stress distribution in conical and cylindrical parts of structure is investigated. In addition, the effect of the inter...

Thin wall ductile iron casting as a substitute for aluminum alloy casting in automotive industry

Directory of Open Access Journals (Sweden)

M. Górny

2009-01-01

Full Text Available In paper it is presented thin wall ductile iron casting (TWDI as a substitute of aluminium alloy casting. Upper control arm made of ductile iron with wall thickness ranging from 2 – 3.7 mm was produced by inmold process. Structure, mechanical properties and computer simulations were investigated. Structural analysis of TWDI shows pearlitic-ferritic matrix free from chills and porosity. Mechanical testing disclose superior ultimate tensile strength (Rm, yield strength (Rp0,2 and slightly lower elongation (E of TWDI in comparison with forged control arm made of aluminium alloy (6061-T6. Moreover results of computer simulation of static loading for tested control arms are presented. Analysis show that the light-weight ductile iron casting can be loaded to similar working conditions as the forged Al alloy without any potential failures.

Vesicular thick-walled swollen hyphae in pulmonary zygomycosis.

Science.gov (United States)

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.

Halo current and resistive wall simulations of ITER

International Nuclear Information System (INIS)

Strauss, H.R.; Zheng Linjin; Kotschenreuther, M.; Park, W.; Jardin, S.; Breslau, J.; Pletzer, A.; Paccagnella, R.; Sugiyama, L.; Chu, M.; Chance, M.; Turnbull, A.

2005-01-01

A number of ITER relevant problems in resistive MHD concern the effects of a resistive wall: vertical displacement events (VDE), halo currents caused by disruptions, and resistive wall modes. Simulations of these events have been carried out using the M3D code. We have verified the growth rate scaling of VDEs, which is proportional to the wall resistivity. Simulations have been done of disruptions caused by large inversion radius internal kink modes, as well as by nonlinear growth of resistive wall modes. Halo current flowing during the disruption has asymmetries with toroidal peaking factor up to about 3. VDEs have larger growth rates during disruption simulations, which may account for the loss of vertical feedback control during disruptions in experiments. Further simulations have been made of disruptions caused by resistive wall modes in ITER equilibria. For these modes the toroidal peaking factor is close to 1. Resistive wall modes in ITER and reactors have also been investigated utilizing the newly developed AEGIS (Adaptive EiGenfunction Independent Solution) linear full MHD code, for realistically shaped, fully toroidal equilibria. The AEGIS code uses an adaptive mesh in the radial direction which allows thin inertial layers to be accurately resolved, such as those responsible for the stabilization of resistive wall modes (RWM) by plasma rotation. Stabilization of resistive wall modes by rotation and wall thickness effects are examined. (author)

Evaluation of advanced automatic PET segmentation methods using nonspherical thin-wall inserts

International Nuclear Information System (INIS)

Berthon, B.; Marshall, C.; Evans, M.; Spezi, E.

2014-01-01

Purpose: The use of positron emission tomography (PET) within radiotherapy treatment planning requires the availability of reliable and accurate segmentation tools. PET automatic segmentation (PET-AS) methods have been recommended for the delineation of tumors, but there is still a lack of thorough validation and cross-comparison of such methods using clinically relevant data. In particular, studies validating PET segmentation tools mainly use phantoms with thick plastic walls inserts of simple spherical geometry and have not specifically investigated the effect of the target object geometry on the delineation accuracy. Our work therefore aimed at generating clinically realistic data using nonspherical thin-wall plastic inserts, for the evaluation and comparison of a set of eight promising PET-AS approaches. Methods: Sixteen nonspherical inserts were manufactured with a plastic wall of 0.18 mm and scanned within a custom plastic phantom. These included ellipsoids and toroids derived with different volumes, as well as tubes, pear- and drop-shaped inserts with different aspect ratios. A set of six spheres of volumes ranging from 0.5 to 102 ml was used for a baseline study. A selection of eight PET-AS methods, written in house, was applied to the images obtained. The methods represented promising segmentation approaches such as adaptive iterative thresholding, region-growing, clustering and gradient-based schemes. The delineation accuracy was measured in terms of overlap with the computed tomography reference contour, using the dice similarity coefficient (DSC), and error in dimensions. Results: The delineation accuracy was lower for nonspherical inserts than for spheres of the same volume in 88% cases. Slice-by-slice gradient-based methods, showed particularly lower DSC for tori (DSC 0.76 except for tori) but showed the largest errors in the recovery of pears and drops dimensions (higher than 10% and 30% of the true length, respectively). Large errors were visible

Long-Term Bending Creep Behavior of Thin-Walled CFRP Tendon Pretensioned Spun Concrete Poles

Directory of Open Access Journals (Sweden)

Giovanni P. Terrasi

2014-07-01

Full Text Available This paper discusses the long-term behavior of a series of highly-loaded, spun concrete pole specimens prestressed with carbon fiber-reinforced polymer (CFRP tendons, which were subjected to outdoor four-point bending creep tests since 1996 in the frame of collaboration with the Swiss precast concrete producer, SACAC (Società Anonima Cementi Armati Centrifugati. The 2 m span cylindrical beams studied are models for lighting poles produced for the last 10 years and sold on the European market. Five thin-walled pole specimens were investigated (diameter: 100 mm; wall-thickness: 25–27 mm. All specimens were produced in a pretensioning and spinning technique and were prestressed by pultruded CFRP tendons. Initially, two reference pole specimens were tested in quasi-static four-point bending to determine the short-term failure moment and to model the short-term flexural behavior. Then, three pole specimens were loaded to different bending creep moments: while the lowest loaded specimen was initially uncracked, the second specimen was loaded with 50% of the short-term bending failure moment and exhibited cracking immediately after load introduction. The highest loaded pole specimen sustained a bending moment of 72% of the short-term bending failure moment for 16.5 years before failing in July 2013, due to the bond failure of the tendons, which led to local crushing of the high-performance spun concrete (HPSC. Besides this, long-term monitoring of the creep tests has shown a limited time- and temperature-dependent increase of the deflections over the years, mainly due to the creep of the concrete. A concrete creep-based model allowed for the calculation of the long-term bending curvatures with reasonable accuracy. Furthermore, the pole specimens showed crack patterns that were stable over time and minimal slippage of the tendons with respect to the pole’s end-faces for the two lower load levels. The latter proves the successful and durable

Parametric analysis of AAR influent factors on thin-walled columns

Directory of Open Access Journals (Sweden)

E. L. Madureira

Full Text Available ABSTRACTThe chemical reaction involving the alkalis of the cement and some minerals of the concrete aggregates, the Alkali-Aggregate Reaction or, simply, the AAR, promotes swelling and material damages. Despite the development stage of the researches on this pathology effects, its solution modeling still lacks refinement. The numerical simulation is an important resource for the structural damages evaluation due to AAR, and their repairs. The aim of this work is the numerical simulation of concrete thin-walled columns, affected by the AAR, from the finite element approximation on an orthotropic nonlinear framework, and a thermodynamic model designed to the assessment of the AAR swelling, with highlight on the compressive stress, the reinforcement and the temperature influences on the phenomenon. The obtained results revealed that the AAR induced the concrete strength decrease and the consequent reduction in preventive safety margin to the material failure, being more precocious at higher temperatures.

Design optimization of a thin walled pressure vessel

International Nuclear Information System (INIS)

Sadiq, S.

2001-01-01

Design evaluation of a pressure vessel is not only to build confidence on its integrity but also to reduce structural weight and enhance the performance of the structure. Pressure vessel, e.g., a rocket motor not only has to withstand the high operating temperatures but it must also be able to survive the internal pressures and external aerodynamic forces and bending stresses during its operation in flight. A research program was devised to study the stresses, which are generated in a thin walled pressure vessel during actual operation and its simulation with cold testing technique, i.e., by means of hydrostatic testing employing electrical resistance strain gauges on the external surface of the cylinder. The objective of the research was to uphold the performance of the vessel by reducing its thickness from 6.09 to 5.5 mm (which of course reduces the safety factor margin from 1.8 to 1.5); thereby curtailing the overall structural weight and maintaining the efficiency of the vessel itself during its live operation. The techniques employed were hydrostatic testing, data acquisition system for obtaining data on strains from the electrical resistance strain gauges and later employing V on Mises yield criterion empirical relation to computer the stresses in hoop and longitudinal directions. (author)

Experimental study on buckling and ultimate strength of thin-walled box stub columns; Usuniku hakogata danmen buzai no zakutsu / shukyoku kyodo tokusei ni kansuru jikkenteki kenkyu

Energy Technology Data Exchange (ETDEWEB)

Nakai, H.; Kitada, T. [Osaka City Univ. (Japan); Oryu, T. [Kawasaki Heavy Industries Ltd., Kobe (Japan)

1998-10-21

Thin-walled box stub columns such as beams of cable-stayed bridge, suspension bridge tower, arch rib of arch bridge and steel piers and so forth can also bear torsion at the same time besides compression and bending. These thin-walled box stub columns may achieve ultimate condition before reaching to plastic condition due to the effect of local buckling and so forth. Accordingly, it is the important topic to study the properties regarding ultimate strength of thin-walled box members in order to evaluate correctly the effect on load bearing resistance of local buckling. In this report, validity of load bearing resistance curve and ultimate strength interaction curve proposed by authors was studied using load bearing capacity experiment results. As a result, all ultimate strengths obtained by the experiment were higher than the ultimate strengths estimated by load bearing capacity curve and ultimate strength interaction curve. Further, it was revealed that the specimens subjected to torsion or subjected to bending and torsion and so forth exceeded the plastic strength due to the effect of strain hardening. 12 refs., 14 figs., 4 tabs.

Arabidopsis wat1 (walls are thin1)-mediated resistance to the bacterial vascular pathogen, Ralstonia solanacearum, is accompanied by cross-regulation of salicylic acid and tryptophan metabolism

NARCIS (Netherlands)

Denancé, N.; Ranocha, P.; Oria, N.; Barlet, X.; Rivière, M.P.; Yadeta, K.A.; Hoffmann, L.; Perreau, F.; Clément, G.; Maia-Grondard, A.; Berg, van den G.C.M.; Savelli, B.; Fournier, S.; Aubert, Y.; Pelletier, S.; Thomma, B.P.H.J.; Molina, A.; Jouanin, L.; Marco, Y.; Goffner, D.

2013-01-01

Inactivation of Arabidopsis WAT1 (Walls Are Thin1), a gene required for secondary cell-wall deposition, conferred broad-spectrum resistance to vascular pathogens, including the bacteria Ralstonia solanacearum and Xanthomonas campestris pv. campestris, and the fungi Verticillium dahliae and

Transparent and flexible supercapacitors with single walled carbon nanotube thin film electrodes.

Science.gov (United States)

Yuksel, Recep; Sarioba, Zeynep; Cirpan, Ali; Hiralal, Pritesh; Unalan, Husnu Emrah

2014-09-10

We describe a simple process for the fabrication of transparent and flexible, solid-state supercapacitors. Symmetric electrodes made up of binder-free single walled carbon nanotube (SWCNT) thin films were deposited onto polydimethylsiloxane substrates by vacuum filtration followed by a stamping method, and solid-state supercapacitor devices were assembled using a gel electrolyte. An optical transmittance of 82% was found for 0.02 mg of SWCNTs, and a specific capacitance of 22.2 F/g was obtained. The power density can reach to 41.5 kW · kg(-1) and shows good capacity retention (94%) upon cycling over 500 times. Fabricated supercapacitors will be relevant for the realization of transparent and flexible devices with energy storage capabilities, displays and touch screens in particular.

Highly transparent and conductive thin films fabricated with nano-silver/double-walled carbon nanotube composites.

Science.gov (United States)

Lee, Shie-Heng; Teng, Chih-Chun; Ma, Chen-Chi M; Wang, Ikai

2011-12-01

This study develops a technique for enhancing the electrical conductivity and optical transmittance of transparent double-walled carbon nanotube (DWNT) film. Silver nanoparticles were modified with a NH(2)(CH(2))(2)SH self-assembled monolayer terminated by amino groups and subsequent surface condensation that reacted with functionalized DWNTs. Ag nanoparticles were grafted on the surface of the DWNTs. The low sheet resistance of the resulting thin conductive film on a polyethylene terephthalate (PET) substrate was due to the increased contact areas between DWNTs and work function by grafting Ag nanoparticles on the DWNT surfaces. Increasing the contact area between DWNTs and work function improved the conductivity of the DWNT-Ag thin films. The prepared DWNT-Ag thin films had a sheet resistance of 53.4 Ω/sq with 90.5% optical transmittance at a 550 nm wavelength. After treatment with HNO(3) and annealing at 150 °C for 30 min, a lower sheet resistance of 45.8 Ω/sq and a higher transmittance of 90.4% could be attained. The value of the DC conductivity to optical conductivity (σ(DC)/σ(OP)) ratio is 121.3. Copyright © 2011 Elsevier Inc. All rights reserved.

Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems

Science.gov (United States)

Fakkaew, Wichaphon; Cole, Matthew O. T.

2018-06-01

This paper investigates the vibration arising in a thin-walled cylindrical rotor subject to small non-circularity and coupled to discrete space-fixed radial bearing supports. A Fourier series description of rotor non-circularity is incorporated within a mathematical model for vibration of a rotating annulus. This model predicts the multi-harmonic excitation of the rotor wall due to bearing interactions. For each non-circularity harmonic there is a set of distinct critical speeds at which resonance can potentially arise due to flexural mode excitation within the rotor wall. It is shown that whether each potential resonance occurs depends on the multiplicity and symmetry of the bearing supports. Also, a sufficient number of evenly spaced identical supports will eliminate low order resonances. The considered problem is pertinent to the design and operation of thin-walled rotors with active magnetic bearing (AMB) supports, for which small clearances exist between the rotor and bearing and so vibration excitation must be limited to avoid contacts. With this motivation, the mathematical model is further developed for the case of a distributed array of electromagnetic actuators controlled by feedback of measured rotor wall displacements. A case study involving an experimental system with short cylindrical rotor and a single radial AMB support is presented. The results show that flexural mode resonance is largely avoided for the considered design topology. Moreover, numerical predictions based on measured non-circularity show good agreement with measurements of rotor wall vibration, thereby confirming the validity and utility of the theoretical model.

Development of Wall Thinning Distinction Method using the Multi-inspecting UT Data of Carbon Steel Piping

Energy Technology Data Exchange (ETDEWEB)

Hwang, Kyeong Mo; Yun, Hun; Lee, Chan Kyoo [KEPCO E and C, Yongin (Korea, Republic of)

2012-05-15

To manage the wall thinning of carbon steel piping in nuclear power plants, the utility of Korea has performed thickness inspection for some quantity of pipe components during refueling outages and determined whether repair or replacement after evaluating UT (Ultrasonic Test) data. When the existing UT data evaluation methods, such as Band, Blanket, PTP (Point to Point) Methods, are applied to a certain pipe component, unnecessary re-inspecting situations may be generated even though the component does not thinned. In those cases, economical loss caused by repeated inspection and problems of maintaining the pipe integrity followed by decreasing of newly inspected components may be generated. EPRI (Electric Power Research Institute) in USA has suggested several statistical methods, TPM (Total Point Method), LSS (Least Square Slope) Method, etc. to distinguish whether multiple inspecting components have thinned or not. This paper presents the analysis results for multiple inspecting components over three times based on both NAM (Near Area of Minimum) Method developed by KEPCO-E and C and the other methods suggested by EPRI.

The local domain wall position in ferromagnetic thin wires: simultaneous measurement of resistive and transverse voltages at multiple points

International Nuclear Information System (INIS)

Hanada, R.; Sugawara, H.; Aoki, Y.; Sato, H.; Shigeto, K.; Shinjo, T.; Ono, T.; Miyajima, H.

2002-01-01

We have simultaneously measured the field dependences of voltages at multiple pairs of resistance and transverse voltage probes in ferromagnetic wires (with either magnetic or non-magnetic voltage probes). Both the resistive (through the giant magnetoresistance and anisotropic magnetoresistance) and transverse voltages (through the planar Hall effect) exhibit abrupt jumps, reflecting discrete motion of domain walls or rotations of magnetization. Voltage probes, even if non-magnetic, are found to affect the jump fields depending on the sample conditions. We demonstrate that the specific information on the domain (wall) motion along a thin ferromagnetic wire could be obtained from the jump fields. (author)

Dynamics of plane-symmetric thin walls in general relativity

International Nuclear Information System (INIS)

Wang, A.

1992-01-01

Plane walls (including plane domain walls) without reflection symmetry are studied in the framework of Einstein's general relativity. Using the distribution theory, all the Einstein field equations and Bianchi identities are split into two groups: one holding in the regions outside of the wall and the other holding at the wall. The Einstein field equations at the wall are found to take a very simple form, and given explicitly in terms of the discontinuities of the metric coefficients and their derivatives. The Bianchi identities at the wall are also given explicitly. Using the latter, the interaction of a plane wall with gravitational waves and some specific matter fields is studied. In particular, it is found that, when a gravitational plane wave passes through a wall, if the wall has no reflection symmetry, the phenomena, such as reflection, stimulation, or absorption, in general, occur. It is also found that, unlike for gravitational waves, a massless scalar wave or an electromagnetic wave continuously passes through a wall without any reflection. The repulsion and attraction of a plane wall are also studied. It is found that the acceleration of an observer who is at rest relative to the wall usually consists of three parts: one is due to the force produced by the wall, the second is due to the force produced by the space-time curvature, which is zero if the wall has reflection symmetry, and the last is due to the accelerated motion of the wall. As a result, a repulsive (attractive) plane wall may not be repulsive (attractive) at all. Finally, the collision and interaction among the walls are studied

Numerical modelling of thin-walled Z-columns made of general laminates subjected to uniform shortening

Science.gov (United States)

Teter, Andrzej; Kolakowski, Zbigniew

2018-01-01

The numerical modelling of a plate structure was performed with the finite element method and a one-mode approach based on Koiter's method. The first order approximation of Koiter's method enables one to solve the eigenvalue problem. The second order approximation describes post-buckling equilibrium paths. In the finite element analysis, the Lanczos method was used to solve the linear problem of buckling. Simulations of the non-linear problem were performed with the Newton-Raphson method. Detailed calculations were carried out for a short Z-column made of general laminates. Configurations of laminated layers were non-symmetric. Due to possibilities of its application, the general laminate is very interesting. The length of the samples was chosen to obtain the lowest value of local buckling load. The amplitude of initial imperfections was 10% of the wall thickness. Thin-walled structures were simply supported on both ends. The numerical results were verified in experimental tests. A strain-gauge technique was applied. A static compression test was performed on a universal testing machine and a special grip, which consisted of two rigid steel plates and clamping sleeves, was used. Specimens were obtained with an autoclave technique. Tests were performed at a constant velocity of the cross-bar equal to 2 mm/min. The compressive load was less than 150% of the bifurcation load. Additionally, soft and thin pads were used to reduce inaccuracy of the sample ends.

Validation of nonlinear FEA models of a thin-walled elbow under extreme loading conditions for Sodium-cooled Fast Reactors

International Nuclear Information System (INIS)

Watakabe, Tomoyoshi; Wakai, Takashi; Jin, Chuanrong; Usui, Yoshiya; Sakai, Shinkichi; Ooshika, Junji; Tsukimori, Kazuyuki

2015-01-01

For the purpose of confirming failure modes and safety margin, some studies on the ultimate strength of thin-walled piping components for Sodium-cooled Fast Reactors (SFRs) under extreme loading conditions such as large earthquakes have been reported these several years. Nonlinear finite element analysis has been applied in these studies to simulate buckling and yielding with large deformation, whose accuracy is dependent on the element type, the mesh size, the elasto-plastic model and so on. It is important to check the validation of a finite element model for nonlinear analysis especially under extreme loading conditions. This paper presents static and dynamic analyses of a thin-walled elbow with large deformation under large seismic loading, and discusses the validation of the FEA models comparing with experimental results. The finite element analysis models in this study are generated by shell elements for a stainless steel pipe elbow of diameter-to-thickness ratio 59:1 similar to the main pipe of SFRs, which is used for shaking table tests. At first, a static analysis is carried out for an in-plane monotonic bending test, in order to confirm that the shell element is appropriate to the large deformation analysis and the material parameters are proper for the strain level in the experiments. And then, a dynamic in-plane bending test with the maximum acceleration of 11.7G is simulated by the nonlinear FEA with stiffness-proportional damping. The influence of mesh sizes on results is investigated, to determine proper mesh sizes and reduce the computational cost. Finally, comparing the results of the FEM analyses with those of experiments, it is concluded that the appropriately generated FEA models are effective and give accurate results for nonlinear analyses of the thin-walled elbow under large seismic loading. (author)

Study of tensile test behavior of austenitic stainless steel type 347 seamless thin-walled tubes in cold worked condition

Energy Technology Data Exchange (ETDEWEB)

Terui, Clarice, E-mail: clarice.terui@marinha.mil.br [Centro Tecnológico da Marinha em São Paulo (CINA/CTMSP), Iperó, SP (Brazil). Centro Industrial Nuclear da Marinha; Lima, Nelson B. de, E-mail: nblima@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNE-SP), Sao Paulo, SP (Brazil)

2017-07-01

These austenitic stainless steel type 347 seamless thin-walled tubes are potential candidates to be used in fuel elements of nuclear power plants (as PWR - Pressurized Water Reactor). So, their metallurgical condition and mechanical properties, as the tensile strength and yield strength, normally are very restrict in demanding project and design requirements. Several full size tensile tests at room temperature and high temperature (315 deg C) were performed in these seamless tubes in cold-worked condition. The results of specified tensile and yield strengths were achieved but the elongation of the tube, in the geometry of the component, could not be measured at high temperature due to unconventional mode of rupture (helical mode without separation of parts). The average value of elongation was obtained from stress-strain curves of hot tensile tests and was around 5%. The results obtained in this research show that this behavior of the full size tensile test samples of thin-walled tube (wall thickness less than 0.5 mm) in high temperature (315°C) is due to the combination of the manufacturing process, the material (crystallographic structure and chemical composition) and the final geometry of the component. In other words, the strong crystallographic texture of material induced by tube drawing process in addition with the geometry of the component are responsible for the behavior in hot uniaxial tensile tests. (author)

Thin films of single-walled carbon nanotubes promote human osteoblastic cells (Saos-2) proliferation in low serum concentrations

International Nuclear Information System (INIS)

Akasaka, Tsukasa; Yokoyama, Atsuro; Matsuoka, Makoto; Hashimoto, Takeshi; Watari, Fumio

2010-01-01

One strategy used for the regeneration of bone is the development of cell culture substrates and scaffolds that can control osteoblast proliferation and differentiation. In recent investigations, carbon nanotubes (CNTs) have been utilized as scaffolds for osteoblastic cell cultures; however, there are only a few reports describing the proliferation of osteoblastic cells on thin CNT films; in particular, the effects of serum concentration on cell proliferation have not been studied. In the present study, we prepared culture dishes with homogeneous thin or thick films of non-modified CNTs and examined the effect of serum concentrations on human osteoblastic cells (Saos-2) proliferation in these culture dishes. We demonstrated that the ratio of cell proliferation was strongly affected by the concentration of serum. Interestingly, single-walled carbon nanotube (SWNT) thin films were found to be the most effective substrate for the proliferation of Saos-2 cells in low concentrations of serum. Thus, thin SWNT films may be used as an effective biomaterial for the culture of Saos-2 cells in low serum concentrations.

Growth of uniform thin-walled carbon nanotubes with spin-coated Fe catalyst and the correlation between the pre-growth catalyst size and the nanotube diameter

International Nuclear Information System (INIS)

Seah, Choon-Ming; Chai, Siang-Piao; Ichikawa, Satoshi; Mohamed, Abdul Rahman

2013-01-01

Single-walled carbon nanotubes (CNTs) and double-walled CNTs with a selectivity of 93 % were obtained by means of the novel homemade iron catalysts which were spin coated on silicon wafer. The average diameters of the iron particles prepared from the colloidal solutions containing 30, 40, 50, 60, and 70 mmol/L of iron nitrate were 8.2, 5.1, 20.8, 32.2, and 34.7 nm, respectively, and growing thin-walled CNTs with the average diameters of 4.1, 2.2, 9.2, 11.1, and 18.1 nm, respectively. The diameters of the CNTs were correlated with the geometric sizes of the pre-growth catalyst particles. Thin-walled CNTs were found to have a catalyst mean diameter-to-CNT average diameter ratio of 2.31. Iron carbide was formed after the growth of CNTs, and it is believed that during the growth of CNTs, carbon source decomposed and deposited on the surface of catalyst, followed by the diffusion of surface carbon into the iron catalyst particles, resulting in carbon supersaturation state before the growth of CNTs.

Influence of substrate material on the microstructure and optical properties of hot wall deposited SnS thin films

International Nuclear Information System (INIS)

Bashkirov, S.A.; Gremenok, V.F.; Ivanov, V.A.; Shevtsova, V.V.; Gladyshev, P.P.

2015-01-01

Tin monosulfide SnS raises an interest as a promising material for photovoltaics. The influence of the substrate material on the microstructure and optical properties of SnS thin films with [111] texture obtained by hot wall vacuum deposition on glass, molybdenum and indium tin oxide substrates is reported. The lattice parameters for layers grown on different substrates were determined by X-ray diffraction and their deviations from the data reported in the literature for single α-SnS crystals were discussed. The change in the degree of preferred orientation of the films depending on the substrate material is observed. The direct nature of the optical transitions with the optical band gap of 1.15 ± 0.01 eV is reported. - Highlights: • SnS thin films were hot wall deposited on glass, molybdenum and indium tin oxide. • Physical properties of the films were studied with respect to the substrate type. • The SnS lattice parameter deviations were observed and the explanation was given. • The direct optical transitions with the band gap of 1.15 ± 0.01 eV were observed

Economic Analysis of Installing Fixed and Removable Insulation for Pipe Wall Thinning Management

Energy Technology Data Exchange (ETDEWEB)

Hwang, Kyeongmo; Yun, Hun [KEPCO E and C, Gimcheon (Korea, Republic of)

2016-12-15

To perform ultrasonic testing (UT) thickness measurement of the secondary side piping installed in nuclear power plants, the insulation for preventing heat loss should be removed. The type of insulation can be divided into fixed and removable insulation. Fixed and removable insulation have their own strengths and weaknesses. Removable insulation has been installed in the components susceptible to wall thinning caused by FAC and erosion from Shin-Kori unit 1, which commenced its commercial operation in 2011. In this paper, the number of repeated inspections of components and the number of replacements of fixed insulation were estimated and a more economical way was identified based on the manufacturing and installation costs for fixed and removable insulation.

Degenerated shell element for geometrically nonlinear analysis of thin-walled piezoelectric active structures

International Nuclear Information System (INIS)

Marinković, D; Köppe, H; Gabbert, U

2008-01-01

Active piezoelectric thin-walled structures, especially those with a notably higher membrane than bending stiffness, are susceptible to large rotations and transverse deflections. Recent investigations conducted by a number of researchers have shown that the predicted behavior of piezoelectric structures can be significantly influenced by the assumption of large displacements and rotations of the structure, thus demanding a geometrically nonlinear formulation in order to investigate it. This paper offers a degenerated shell element and a simplified formulation that relies on small incremental steps for the geometrically nonlinear analysis of piezoelectric composite structures. A set of purely mechanical static cases is followed by a set of piezoelectric coupled static cases, both demonstrating the applicability of the proposed formulation

Survey of a wireless NDT service for a nuclear piping wall thinning defect

International Nuclear Information System (INIS)

Choi, Yoo Rark; Lee, Jae Cheol

2008-01-01

The wireless sensor network has been issued for several years. The nuclear power plants all around world have adapted many kinds of sensor technologies for inspections and diagnostics of main instruments. Even though wireless sensor is more useful than wired sensor, wireless sensor based applications haven't been used in nuclear power plants because of the authorization of a jamming, an electromagnetic interference and so on. A wireless sensor uses a battery for its operations, but this battery can't be used for a long haul. It causes a battery change problem. There aren't any wireless sensor based NDT for a piping wall thinning part. We will describe a method of how to develop it in this paper

Effect of Eccentricity of Load on Critical Force of Thin-Walled Columns CFRP

Directory of Open Access Journals (Sweden)

Pawel Wysmulski

2017-09-01

Full Text Available The subject of study was a thin-walled C-section made of carbon fiber reinforced polymer (CFRP. Column was subjected to eccentric compression in the established direction. In the computer simulation, the boundary conditions were assumed in the form of articulated support of the sections of the column. Particular studies included an analysis of the effects of eccentricity on the critical force value. The research was conducted using two independent research methods: numerical and experimental. Numerical simulations were done using the finite element method using the advanced system Abaqus®. The high sensitivity of the critical force value corresponding to the local buckling of the channel section to the load eccentricity was demonstrated.

Strength tests of thin-walled elliptic duralumin cylinders in pure bending and in combined pure bending and torsion

Science.gov (United States)

Lundquist, Eugene E; Stowell, Elbridge Z

1942-01-01

An analysis is presented of the results of tests made by the Massachusetts Institute of Technology and by the National Advisory Committee for Aeronautics on an investigation of the strength of thin-walled circular and elliptic cylinders in pure bending and in combined torsion and bending. In each of the loading conditions, the bending moments were applied in the plane of the major axis of the ellipse.

Development of laser cladding system to repair wall thinning of 1-inch heat exchanger tube

International Nuclear Information System (INIS)

Terada, Takaya

2013-01-01

We developed a laser cladding system to repair the inner wall wastage of heat exchanger tubes. Our system, which is designed to repair thinning tube walls within 100 mm from the edge of a heat exchanger tube, consists of a fiber laser, a composite-type optical fiberscope, a coupling device, a laser processing head, and a wire-feeding device. All of these components were reconfigured from the technologies of FBR maintenance. The laser processing head, which has a 15-mm outer diameter, was designed to be inserted into a 1-inch heat exchanger tube. We mounted a heatproof broadband mirror for laser cladding and fiberscope observation with visible light inside the laser processing head. The wire-feeding device continuously supplied 0.4-mm wire to the laser irradiation spot with variable feeding speeds from 0.5 to 20 mm/s. We are planning to apply our proposed system to the maintenance of aging industrial plants. (author)

Rational use of anchor pile material of the thin retaining walls

Directory of Open Access Journals (Sweden)

Yushkov Boris Semenovich

2014-12-01

Full Text Available The article considers the urgency of application of the reinforced concrete anchor piles in the constructions of retaining structures associated with the possibility of establishing rigid joint of element interface and more durable pile constructions in the soil. The features of the inclined anchor piles work as a part of sheet-pile retaining walls are noted. There was performed a study of the stress-strain state of the inclined reinforced concrete anchor piles of the thin sheet-pile wall with the reinforced concrete face members of T-section, combined with piles by a longitudinal beam. The authors consider a constructive scheme of retaining structure and list the applied loads. The efforts in the anchor piles were determined. The bending-moment curves show the character of the force distribution along the pile. A form of the pile ensuring the rational distribution of material along the pile is presented. The distribution of efforts along the length and effect of filling on its operation in the soil were accepted as the criteria of construction solution for a pile. The substantiation of the proposed design of pile is presented in terms of its stress-strain state and the rational use of material. The authors made conclusions on the reasonability of adopted design solutions associated with an increase in the flexural strength of pile, increment of the ultimate pullout capacity, stability improvement, effective use of backfill and exception of the «out of operation» areas of the pile.

An assessment for the erosion rate of DEMO first wall

Science.gov (United States)

Tokar, M. Z.

2018-01-01

In a fusion reactor a significant fraction of plasma particles lost from the confined volume will reach the vessel wall. The recombination of these charged species, electrons and ions of hydrogen isotopes, is a source of neutral molecules and atoms, recycling back into the plasma. Here they participate, in particular, in charge-exchange (c-x) collisions with the plasma ions and, as a result, atoms of high energies with chaotically oriented velocities are generated. A significant fraction of these hot neutrals will hit the wall, leading, as well as the outflowing fuel and impurity ions, to its erosion, limiting the reactor operation time. The rate of the wall erosion in DEMO is assessed by applying a one-dimensional model which takes into account the transport of charged and neutral species across the flux surfaces in the main part of the scrape-off layer, beyond the X-point vicinity and divertor, and by considering the shift of the centers of flux surfaces, their elongation and triangularity. Atoms generated by c-x of recycling neutrals are modeled kinetically to define firmly their energy spectrum, being of particular importance for the erosion assessment. It is demonstrated the erosion rate of the DEMO wall armor of tungsten will have a pronounced ballooning character with a significant maximum of 0.3 mm per full power year at the low field side, decreasing with an increase in the anomalous perpendicular transport in the ‘far’ SOL or the plasma density at the separatrix.

Shielding synchrotron light sources: Advantages of circular shield walls tunnels

Energy Technology Data Exchange (ETDEWEB)

Kramer, S.L. [Design and Accelerator Operations Consulting, 568 Wintergreen Ct Ridge, NY 11961 (United States); Ghosh, V.J.; Breitfeller, M. [NSLS-II, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2016-08-11

Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produce significantly higher neutron component dose to the experimental floor than lower energy injection and ramped operations. High energy neutrons produced in the forward direction from thin target beam losses are a major component of the dose rate outside the shield walls of the tunnel. The convention has been to provide thicker 90° ratchet walls to reduce this dose to the beam line users. We present an alternate circular shield wall design, which naturally and cost effectively increases the path length for this forward radiation in the shield wall and thereby substantially decreasing the dose rate for these beam losses. This shield wall design will greatly reduce the dose rate to the users working near the front end optical components but will challenge the beam line designers to effectively utilize the longer length of beam line penetration in the shield wall. Additional advantages of the circular shield wall tunnel are that it's simpler to construct, allows greater access to the insertion devices and the upstream in tunnel beam line components, as well as reducing the volume of concrete and therefore the cost of the shield wall.

Erosion corrosion in power plant piping systems - Calculation code for predicting wall thinning

International Nuclear Information System (INIS)

Kastner, W.; Erve, M.; Henzel, N.; Stellwag, B.

1990-01-01

Extensive experimental and theoretical investigations have been performed to develop a calculation code for wall thinning due to erosion corrosion in power plant piping systems. The so-called WATHEC code can be applied to single-phase water flow as well as to two-phase water/steam flow. Only input data which are available to the operator of the plant are taken into consideration. Together with a continuously updated erosion corrosion data base the calculation code forms one element of a weak point analysis for power plant piping systems which can be applied to minimize material loss due to erosion corrosion, reduce non-destructive testing and curtail monitoring programs for piping systems, recommend life-extending measures. (author). 12 refs, 17 figs

Failure analysis of the boiler water-wall tube

Directory of Open Access Journals (Sweden)

S.W. Liu

2017-10-01

Full Text Available Failure analysis of the boiler water-wall tube is presented in this work. In order to examine the causes of failure, various techniques including visual inspection, chemical analysis, optical microscopy, scanning electron microscopy and energy dispersive spectroscopy were carried out. Tube wall thickness measurements were performed on the ruptured tube. The fire-facing side of the tube was observed to have experienced significant wall thinning. The composition of the matrix material of the tube meets the requirements of the relevant standards. Microscopic examinations showed that the spheroidization of pearlite is not very obvious. The failure mechanism is identified as a result of the significant localized wall thinning of the boiler water-wall tube due to oxidation.

Analytical Investigation of Elastic Thin-Walled Cylinder and Truncated Cone Shell Intersection Under Internal Pressure.

Science.gov (United States)

Zamani, J; Soltani, B; Aghaei, M

2014-10-01

An elastic solution of cylinder-truncated cone shell intersection under internal pressure is presented. The edge solution theory that has been used in this study takes bending moments and shearing forces into account in the thin-walled shell of revolution element. The general solution of the cone equations is based on power series method. The effect of cone apex angle on the stress distribution in conical and cylindrical parts of structure is investigated. In addition, the effect of the intersection and boundary locations on the circumferential and longitudinal stresses is evaluated and it is shown that how quantitatively they are essential.

Ultrasonic Measurement of Erosion/corrosion Rates in Industrial Piping Systems

Science.gov (United States)

Sinclair, A. N.; Safavi, V.; Honarvar, F.

2011-06-01

Industrial piping systems that carry aggressive corrosion or erosion agents may suffer from a gradual wall thickness reduction that eventually threatens pipe integrity. Thinning rates could be estimated from the very small change in wall thickness values measured by conventional ultrasound over a time span of at least a few months. However, measurements performed over shorter time spans would yield no useful information—minor signal distortions originating from grain noise and ultrasonic equipment imperfections prevent a meaningful estimate of the minuscule reduction in echo travel time. Using a Model-Based Estimation (MBE) technique, a signal processing scheme has been developed that enables the echo signals from the pipe wall to be separated from the noise. This was implemented in a laboratory experimental program, featuring accelerated erosion/corrosion on the inner wall of a test pipe. The result was a reduction in the uncertainty in the wall thinning rate by a factor of four. This improvement enables a more rapid response by system operators to a change in plant conditions that could pose a pipe integrity problem. It also enables a rapid evaluation of the effectiveness of new corrosion inhibiting agents under plant operating conditions.

Flow rate dependency of critical wall shear stress in a radial-flow cell

DEFF Research Database (Denmark)

Detry, J.G.; Jensen, Bo Boye Busk; Sindic, M.

2009-01-01

In the present work, a radial-flow cell was used to study the removal of starch particle aggregates from several solid substrates (glass, stainless steel, polystyrene and PTFE) in order to determine the critical wall shear stress value for each case. The particle aggregates were formed by aspersion...... of a water or ethanol suspension of starch granules on the surfaces. Depending on the substrate and on the suspending liquid, the aggregates differed in size and shape. Aggregate removal was studied at two flow rates. At the lower flow rate (Re-inlet = 955), the values of critical wall shear stress...... for the different surfaces suggested that capillary forces were, for all of them, playing an important role in aggregate adhesion since aqueous based aggregates were always more difficult to remove. At the higher flow rate (Re-inlet = 2016) the critical wall shear stress increased as a result of the change...

Thin and flexible all-solid supercapacitor prepared from novel single wall carbon nanotubes/polyaniline thin films obtained in liquid-liquid interfaces

Science.gov (United States)

de Souza, Victor Hugo Rodrigues; Oliveira, Marcela Mohallem; Zarbin, Aldo José Gorgatti

2014-08-01

The present work describes for the first time the synthesis and characterization of single wall carbon nanotubes/polyaniline (SWNTs/PAni) nanocomposite thin films in a liquid-liquid interface, as well as the subsequent construction of a flexible all-solid supercapacitor. Different SWNTs/PAni nanocomposites were prepared by varying the ratio of SWNT to aniline, and the samples were characterized by scanning and transmission electron microscopy, Raman and UV-Vis spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The pseudo-capacitive behavior of the nanocomposites was evaluated by charge/discharge galvanostatic measurements. The presence of the SWNTs affected the electronic and vibrational properties of the polyaniline and also improved the pseudo-capacitive behavior of the conducting polymer. A very thin and flexible all-solid device was manufactured using two electrodes (polyethylene terephthalate-PET covered with the SWNT/PAni nanocomposite separated by a H2SO4-PVA gel electrolyte). The pseudo-capacitive behavior was characterized by a volumetric specific capacitance of approximately 76.7 F cm-3, even under mechanical deformation, indicating that this nanocomposite has considerable potential for application in new-generation energy storage devices.

Clinical significance of exercise-induced left ventricular wall motion abnormality occurring at a low heart rate

International Nuclear Information System (INIS)

Kimchi, A.; Rozanski, A.; Fletcher, C.; Maddahi, J.; Swan, H.J.; Berman, D.S.

1987-01-01

We studied the relationship between the heart rate at the time of onset of exercise-induced wall motion abnormality and the severity of coronary artery disease in 89 patients who underwent exercise equilibrium radionuclide ventriculography as part of their evaluation for coronary artery disease. Segmental wall motion was scored with a five-point system (3 = normal; -1 = dyskinesis); a decrease of one score defined the onset of wall motion abnormality. The onset of wall motion abnormality at less than or equal to 70% of maximal predicted heart rate had 100% predictive accuracy for coronary artery disease and higher sensitivity than the onset of ischemic ST segment depression at similar heart rate during exercise: 36% (25 of 69 patients with coronary disease) vs 19% (13 of 69 patients), p = 0.01. Wall motion abnormality occurring at less than or equal to 70% of maximal predicted heart rate was present in 49% of patients (23 of 47) with critical stenosis (greater than or equal to 90% luminal diameter narrowing), and in only 5% of patients (2 of 42) without such severe stenosis, p less than 0.001. The sensitivity of exercise-induced wall motion abnormality occurring at a low heart rate for the presence of severe coronary artery disease was similar to that of a deterioration in wall motion by more than two scores during exercise (49% vs 53%) or an absolute decrease of greater than or equal to 5% in exercise left ventricular ejection fraction (49% vs 45%)

Characterization of wall conditions in DIII-D

International Nuclear Information System (INIS)

Holtrop, K.L.; Jackson, G.L.; Kellman, A.G.; Lee, R.L.; West, W.P.; Wood, R.D.; Whyte, D.G.

1996-10-01

Wall conditioning in DIII-D is one of the most important factors in achieving reproducible high confinement discharges. For example, the very high confinement mode (VH-mode) was only discovered after boronization, a CVD technique to deposit a thin boron film over the entire surface of the tokamak. In order to evaluate wall conditions and provide a data base to correlate these wall conditions with tokamak discharge performance, a series of nominally identical reference VH-mode discharges (1.6 MA, 2.1 T, double-null diverted) were taken at various times during a series of experimental campaigns with evolving wall conditions. These reference discharges have allowed a quantitative determination of how the wall conditions have evolved. For instance, core carbon and oxygen levels in the VH-mode phase remains at historically low levels during the 1995 run year and there was also a steady decrease in the oxygen levels at plasma initiation during this period. The authors discuss the long term changes in low Z impurities and the effect of wall conditioning techniques such as boronization and baking on these impurities. In addition, the evolution of the deuterium recycling rates will be discussed

A new method for fabrication of thin plates and thin-walled cylinder made of fiber reinforced metal (FRM) and its application for the rotating drum of the nuclear fuel centrifugal separator

International Nuclear Information System (INIS)

Okamura, Tatsuya

1978-01-01

The composite materials using resins as the base materials show the defect that the characteristics deteriorate rapidly at elevated temperature. Therefore the FRMs using relatively ductile metals as the base materials combined with reinforcing fibers have been considered. The result of study on the combination of base materials and fibers and the manufacturing method is rarely reported in Japan. In FRMs, direct contact of fibers mutually must be avoided, especially making nodes lowers the strength extremely. The fibers must be long monofilaments of 0.1 to 0.2 mm diameter. High precision wire winding machines are required for making uniform FRMs. For the diffusion joining of preformed materials, in which fibers are put in order on metallic foils, pressure and heat are applied. The author succeeded to develop the technique for making thin-walled cylinders of FRMs, including the method of winding brittle filaments and the method of pressurizing and heating based on the difference of thermal expansion of dies. The mechanical properties of thin plates and thin-walled cylinders made of monofilaments of B, SiC and SUS and aluminum alloy foils were obtained, and rotation test of the cylinders was carried out. It was clarified that the FRMs of B-Al and SiC-Al groups are very excellent materials, and most suitable for the rotary drums of super-high speed centrifuges. (Kako, I.)

On the adequacy of wall functions to predict condensation rates from steam-noncondensable gas mixtures

Energy Technology Data Exchange (ETDEWEB)

Dehbi, A., E-mail: abdel.dehbi@psi.ch

2013-12-15

Highlights: • Work investigates the effect of near-wall mesh resolution on CFD predictions. • Case study: turbulent condensation in the presence of noncondensable gases. • Wall functions largely underpredict condensation rates at boundary layer onset. • When boundary layer is developed, wall functions predictions are reasonable. • Prescribed wall functions must be compatible with prevailing flow regime. - Abstract: As one looks forward to applying CFD based methods to simulate turbulent flows in larger volumes up to containment scales, the mesh resolution, especially near the walls, becomes one of the main issues dictating the feasibility of the simulation. The wall-function approach is a natural choice to minimize the computational size of the problem and make it tractable. In the current investigation, we compare the wall-function to the fully resolved boundary layer approaches for the prediction of vapor condensation rates on cold walls in the presence of noncondensable gases. We simulate three sets of geometric configurations. The first two sets relate to domains which are small (height of 2 m) and medium (height 4.8 m), and for which experimental heat transfer data are available. In the third set, we look at a hypothetical large 2D rectangular domain in which the condenser height is comparable to that of typical NPP containments (20 m). In the developing region of the boundary layer, it is found that the wall function treatment leads to substantial deviations from the wall resolved approach and available experimental data. Further downstream, however, when the boundary layer is fully developed, the discrepancy is greatly reduced. It is therefore concluded that the wall-function formulation is able to provide predictions of condensation rates that are similar to wall-resolved treatments in simple forced flows for which fully developed boundary layers can be assumed over most of the domain. Care must however be exercised to ensure the chosen wall

The practicality of defensive ice walls: How would the great ice wall in Game of Thrones hold up?

Science.gov (United States)

Truffer, M.

2017-12-01

The Game of Thrones great ice wall is a colossal feature stretching several hundred miles and over 200 m high. Its purpose is to defend the realm from the wildlings. It is generally pictured as a near vertical wall. An ice wall of these proportions poses interesting challenges, mainly because ice acts as a non-linear shear-thinning fluid. A 200 m high vertical wall would create a large effective stress near its base of almost 1.8 MPa. Typical stresses responsible for ice flow in glaciers and ice sheets are more than a magnitude lower (0.1 MPa). Extrapolating a commonly used flow law for temperate ice to such high stresses would lead to strain rates at the bottom of the wall in excess of 1/day, meaning the wall would rapidly collapse and spread laterally under its own weight. To keep the wall stable, it would help to cool it significantly, as the flow of ice is also very temperature dependent. Cooling to a chilly -40 C would reduce strain rates by two orders of magnitude, but this still leads to significant slumping of the wall within just a few weeks. A time-dependent similarity solution for simplified ice flow equations that describe the evolving shape of the ice wall was provided by Halfar (1981), and demonstrates the rapid decay of the wall. A simple estimate can be derived by assuming that ice is a perfectly plastic fluid, able to maintain a basal shear stress of about 0.1 MPa. A stable ice wall would then spread laterally to about 4 km width. The resulting slope would only be steep at the very margin and the ice wall would loose much of its defensive capabilities. I conclude that the ice wall as proposed would not be a practicable defense under typical Earth conditions, and special magical powers would be necessary to maintain its shape, even for just a few days.

stress distribution in continuo ribution in continuous thin ribution

African Journals Online (AJOL)

eobe

studied stresses in thin-walled box girder bridges but stress distribution walled box girder bridges .... the classical thin plate theory and trigonometric series. Lertsima et al. ..... remedied by applying spline finite strip method. Compared to other ...

Enhancement of leak rate estimation model for corroded cracked thin tubes

International Nuclear Information System (INIS)

Chang, Y.S.; Jeong, J.U.; Kim, Y.J.; Hwang, S.S.; Kim, H.P.

2010-01-01

During the last couple of decades, lots of researches on structural integrity assessment and leak rate estimation have been carried out to prevent unanticipated catastrophic failures of pressure retaining nuclear components. However, from the standpoint of leakage integrity, there are still some arguments for predicting the leak rate of cracked components due primarily to uncertainties attached to various parameters in flow models. The purpose of present work is to suggest a leak rate estimation method for thin tubes with artificial cracks. In this context, 23 leak rate tests are carried out for laboratory generated stress corrosion cracked tube specimens subjected to internal pressure. Engineering equations to calculate crack opening displacements are developed from detailed three-dimensional elastic-plastic finite element analyses and then a simplified practical model is proposed based on the equations as well as test data. Verification of the proposed method is done through comparing leak rates and it will enable more reliable design and/or operation of thin tubes.

Thin walled Nb tubes for suspending test masses in interferometric gravitational wave detectors

Energy Technology Data Exchange (ETDEWEB)

Lee, B.H. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia)]. E-mail: bhl@physics.uwa.edu.au; Ju, L. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia); Blair, D.G. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia)

2006-02-13

In a previous Letter, we have shown that the use of orthogonal ribbons could provide a better mirror suspension technique in interferometric gravitational wave antennas. One of the key improvements presented by the orthogonal ribbon is the reduction in the number of violin string modes in the direction of the laser. We have considered more elaborate geometries in recent simulations and obtained a suspension that provides further reduction in the number of violin string modes in the direction of the laser, as well as in the direction orthogonal to the laser. This thin walled niobium tube suspension exhibits a reduction in the number of violin modes to 5 in each direction up to a frequency of 5 kHz. Furthermore, the violin mode thermal noise peaks can be reduced in amplitude by 30 dB.

Thin walled Nb tubes for suspending test masses in interferometric gravitational wave detectors

International Nuclear Information System (INIS)

Lee, B.H.; Ju, L.; Blair, D.G.

2006-01-01

In a previous Letter, we have shown that the use of orthogonal ribbons could provide a better mirror suspension technique in interferometric gravitational wave antennas. One of the key improvements presented by the orthogonal ribbon is the reduction in the number of violin string modes in the direction of the laser. We have considered more elaborate geometries in recent simulations and obtained a suspension that provides further reduction in the number of violin string modes in the direction of the laser, as well as in the direction orthogonal to the laser. This thin walled niobium tube suspension exhibits a reduction in the number of violin modes to 5 in each direction up to a frequency of 5 kHz. Furthermore, the violin mode thermal noise peaks can be reduced in amplitude by 30 dB

Cost optimization of load carrying thin-walled precast high performance concrete sandwich panels

DEFF Research Database (Denmark)

Hodicky, Kamil; Hansen, Sanne; Hulin, Thomas

2015-01-01

and HPCSP’s geometrical parameters as well as on material cost function in the HPCSP design. Cost functions are presented for High Performance Concrete (HPC), insulation layer, reinforcement and include labour-related costs. The present study reports the economic data corresponding to specific manufacturing......The paper describes a procedure to find the structurally and thermally efficient design of load-carrying thin-walled precast High Performance Concrete Sandwich Panels (HPCSP) with an optimal economical solution. A systematic optimization approach is based on the selection of material’s performances....... The solution of the optimization problem is performed in the computer package software Matlab® with SQPlab package and integrates the processes of HPCSP design, quantity take-off and cost estimation. The proposed optimization process outcomes in complex HPCSP design proposals to achieve minimum cost of HPCSP....

Evaluation of transpiration properties of wall greening using evaporation efficiency rate as an index

International Nuclear Information System (INIS)

Suzuki, H.; Misaka, I.; Tashiro, Y.

2007-01-01

In this study, the evaporation efficiency, which is a heat balance parameter necessary for numerical simulation of greening effects, was derived in order quantitatively to evaluate the effects of wall greening panels on improving the thermal environment. The efficiency was determined by monitoring the amount of evapotranspiration from wall greening panels on which either Hedera helix or Euonymus fortunei was planted, calculating the sensible heat-flux from SAT measurements, and determining the convective heat transfer rate, material transfer rate and the difference between the measured and calculated amounts of evapotranspiration. The results showed that: 1) both the convection heat transfer rate and material transfer rate were highly correlated to wind speed, and the derived equations for calculating the rates were functions of wind speed, 2) the mean evaporation efficiency for the monitoring period was 0.25 for Hedera helix and 0.26 for Euonymus fortunei, and 3) the amounts of evaporation from the wall greening panels tested were 4 to 5 mm for both plant species and showed correlations to daily cumulative irradiation

Structural performance of new thin-walled concrete sandwich panel system reinforced with bfrp shear connectors

DEFF Research Database (Denmark)

Hodicky, Kamil; Hulin, Thomas; Schmidt, Jacob Wittrup

2013-01-01

This paper presents a new thin-walled concrete sandwich panel system reinforced with basalt fiber-reinforced plastic (BFRP) with optimum structural performances and a high thermal resistance developed by Connovate and Technical University of Denmark. The shear connecting system made of a BFRP grid...... is described and provides information on the structural design with its advantages. Experimental and numerical investigations of the BFRP connecting systems were performed. The experimental program included testing of small scale specimens by applying shear (push-off) loading and semi-full scale specimens...... on finite element modelling showed that the developed panel system meets the objectives of the research and is expected to have promising future....

Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

Science.gov (United States)

Zsirka, Balázs; Horváth, Erzsébet; Szabó, Péter; Juzsakova, Tatjána; Szilágyi, Róbert K.; Fertig, Dávid; Makó, Éva; Varga, Tamás; Kónya, Zoltán; Kukovecz, Ákos; Kristóf, János

2017-03-01

Surface modification of the halloysite-10 Å mineral with tubular morphology can be achieved by slightly modified procedures developed for the delamination of kaolinite minerals. The resulting delaminated halloysite nanoparticles have unexpected surface/morphological properties that display, new potentials in catalyst development. In this work, a four-step intercalation/delamination procedure is described for the preparation of thin-walled nanoscrolls from the multi-layered hydrated halloysite mineral that consists of (1) intercalation of halloysite with potassium acetate, (2) replacement intercalation with ethylene glycol, (3) replacement intercalation with hexylamine, and (4) delamination with toluene. The intercalation steps were followed by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, thermogravimetry, and infrared spectroscopy. Delamination eliminated the crystalline order and the crystallite size along the 'c'-axis, increased the specific surface area, greatly decreased the thickness of the mineral tubes to a monolayer, and shifted the pore diameter toward the micropore region. Unexpectedly, the removal of residual organics from intercalation steps adsorbed at the nanoscroll surface with a peroxide treatment resulted in partial recovery of crystallinity and increase of crystallite size along the 'c'-crystal direction. The d(001) value showed a diffuse pattern at 7.4-7.7 Å due to the rearrangement of the thin-walled nanoscrolls toward the initial tubular morphology of the dehydrated halloysite-7 Å mineral.

Synthesis of highly conductive thin-walled Al-doped ZnO single-crystal microtubes by a solid state method

Science.gov (United States)

Hu, Shuopeng; Wang, Yue; Wang, Qiang; Xing, Cheng; Yan, Yinzhou; Jiang, Yijian

2018-06-01

ZnO has attracted considerable attention in fundamental studies and practical applications for the past decade due to its outstanding performance in gas sensing, photocatalytic degradation, light harvesting, UV-light emitting/lasing, etc. The large-sized thin-walled ZnO (TW-ZnO) microtube with stable and rich VZn-related acceptors grown by optical vapor supersaturated precipitation (OVSP) is a novel multifunctional optoelectronic material. Unfortunately, the OVSP cannot achieve doping due to the vapor growth process. To obtain doped TW-ZnO microtubes, a solid state method is introduced in this work to achieve thin-walled Al-doping ZnO (TW-ZnO:Al) microtubes with high electrical conductivity. The morphology and microstructures of ZnO:Al microtubes are similar to undoped ones. The Al3+ ions are confirmed to substitute Zn2+ sites and Zn(0/-1) vacancies in the lattice of ZnO by EDS, XRD, Raman and temperature-dependent photoluminescence analyses. The Al dopant acting as a donor level offers massive free electrons to increase the carrier concentrations. The resistivity of the ZnO:Al microtube is reduced down to ∼10-3 Ω·cm, which is one order of magnitude lower than that of the undoped microtube. The present work provides a simple way to achieve doped ZnO tubular components for potential device applications in optoelectronics.

Anelastic deformation of Pb(Zr,Ti)O3 thin films by non-180 deg. ferroelectric domain wall movements during nanoindentation

International Nuclear Information System (INIS)

Alguero, M.; Bushby, A.J.; Reece, M.J.; Seifert, A.

2002-01-01

Lead zirconate titanate Pb(Zr,Ti)O 3 ferroelectric thin films show significant anelastic deformation when indented with spherical tipped indenters. Experiments on films with different Zr/Ti ratio and a mixed , preferred crystallographic orientation have shown that there is a good agreement between the anelastic deformation and the maximum strain achievable by non-180 deg. domain wall movement. An expected increase of the indentation stiffness of the films also accompanies the anelastic deformation because of the single crystal elastic anisotropy. All these observations seem to indicate that non-180 deg. ferroelectric domain wall movements occur under indentation stresses and cause anelasticity. Stresses for maximum anelastic deformation are compared with those for recently reported stress-induced depolarization

Viability of thin wall tube forming of ATF FeCrAl

Energy Technology Data Exchange (ETDEWEB)

Maloy, Stuart Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aydogan, Eda [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Anderoglu, Osman [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lavender, Curt [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-09-16

Fabrication of thin walled tubing of FeCrAl alloys is critical to its success as a candidate enhanced accident-tolerant fuel cladding material. Alloys that are being investigated are Generation I and Generation II FeCrAl alloys produced at ORNL and an ODS FeCrAl alloy, MA-956 produced by Special Metals. Gen I and Gen II FeCrAl alloys were provided by ORNL and MA-956 was provided by LANL (initially produced by Special Metals). Three tube development efforts were undertaken. ORNL led the FeCrAl Gen I and Gen II alloy development and tube processing studies through drawing tubes at Rhenium Corporation. LANL received alloys from ORNL and led tube processing studies through drawing tubes at Century Tubing. PNNL led the development of tube processing studies on MA-956 through pilger processing working with Sandvik Corporation. A summary of the recent progress on tube development is provided in the following report and a separate ORNL report: ORNL/TM-2015/478, “Development and Quality Assessments of Commercial Heat Production of ATF FeCrAl Tubes”.

Failure pressure of straight pipe with wall thinning under internal pressure

International Nuclear Information System (INIS)

Kamaya, Masayuki; Suzuki, Tomohisa; Meshii, Toshiyuki

2008-01-01

The failure pressure of pipe with wall thinning was investigated by using three-dimensional elastic-plastic finite element analyses (FEA). With careful modeling of the pipe and flaw geometry in addition to a proper stress-strain relation of the material, FEA could estimate the precise burst pressure obtained by the tests. FEA was conducted by assuming three kinds of materials: line pipe steel, carbon steel, and stainless steel. The failure pressure obtained using line pipe steel was the lowest under the same flaw size condition, when the failure pressure was normalized by the value of unflawed pipe defined using the flow stress. On the other hand, when the failure pressure was normalized by the results of FEA obtained for unflawed pipe under various flaw and pipe configurations, the failure pressures of carbon steel and line pipe steel were almost the same and lower than that of stainless steel. This suggests that the existing assessment criteria developed for line pipe steel can be applied to make a conservative assessment of carbon steel and stainless steel

Initial phase wall conditioning in KSTAR

International Nuclear Information System (INIS)

Hong, Suk-Ho; Kim, Kwang-Pyo; Kim, Sungwoo; Lee, Dong-Su; Kim, Kyung-Min; Lee, Kun-Su; Kim, Jong-Su; Park, Jae-Min; Kim, Woong-Chae; Kim, Hak-Kun; Park, Kap-Rai; Yang, Hyung-Lyeol; Sun, Jong-Ho; Woo, Hyun-Jong; Lee, Sang-Yong; Lee, Sang-Hwa; Park, Eun-Kyung; Park, Sang-Joon; Kim, Sun-Ho; Wang, Sun-Jung

2011-01-01

The initial phase wall conditioning in KSTAR is depicted. The KSTAR wall conditioning procedure consists of vessel baking, glow discharge cleaning (GDC), ICRH wall conditioning (ICWC) and boronization (Bz). Vessel baking is performed for the initial vacuum conditioning in order to remove various kinds of impurities including H 2 O, carbon and oxygen and for the plasma operation. The total outgassing rates after vessel baking in three successive KSTAR campaigns are compared. GDC is regularly performed as a standard wall cleaning procedure. Another cleaning technique is ICWC, which is useful for inter-shot wall conditioning under a strong magnetic field. In order to optimize the operation time and removal efficiency of ICWC, a parameter scan is performed. Bz is a standard technique to remove oxygen impurity from a vacuum vessel. KSTAR has used carborane powder which is a non-toxic boron-containing material. The KSTAR Bz has been successfully performed through two campaigns: water and oxygen levels in the vacuum vessel are reduced significantly. As a result, KSTAR has achieved its first L-H mode transition, although the input power was marginal for the L-H transition threshold. The characteristics of boron-containing thin films deposited for boronization are investigated.

Liquid-metal flow through a thin-walled elbow in a plane perpendicular to a uniform magnetic field

International Nuclear Information System (INIS)

Walker, J.S.

1986-04-01

This paper presents analytical solutions for the liquid-metal flow through two straight pipes connected by a smooth elbow with the same inside radius. The pipes and the elbow lie in a plane which is perpendicular to a uniform, applied magnetic field. The strength of the magnetic field is assumed to be sufficiently strong that inertial and viscous effects are negligible. This assumption is appropriate for the liquid-lithium flow in the blanket of a magnetic confinement fusion reactor, such as a tokamak. The pipes and the elbow have thin metal walls

Charge-exchange wall physical erosion rates for a proposed INTOR/FED limiter

International Nuclear Information System (INIS)

Heifetz, D.; Schmidt, J.; Ulrickson, M.; Post, D.

1983-01-01

We have analyzed power deposition and physical erosion rates on the first wall and limiter due to charge-exchange neutrals in a proposed pump limiter design for the INTOR/FED tokamak. Plasma conditions were modeled using the one-dimensional plasma transport code baldur. Neutral transport was modeled using a two-dimensional, multispecies Monte Carlo algorithm. No chemical erosion or wall redeposition processes were included. Two possible plasma discharges with different edge densities and temperatures were modeled, a regime with T/sub e/ approx.300 eV and napprox.5 x 10 12 cm - 3 , and a hotter, less dense edge regime produced with pellet fueling. We found that the erosion of the stainless steel vacuum vessel wall was highly localized in each case to the two points just beyond the limiter tips, and to the point directly across from the neutralizer plate, with peak erosion rates approx.2 cm/yr, assuming a 40% duty cycle. The erosion of a carbon limiter, neglecting redeposition and chemical erosion, varied in the two cases from 1.6--4 cm/yr, for the same duty cycle. The hotter, less dense discharge produced less sputtering. However achieving truly tolerable physical sputtering rates may require a very low edge temperature, plasma

Torsional Post-Buckling of a Simply Supported Thin-Walled Open-Section Beam Resting on a Two-Parameter Foundation

Science.gov (United States)

Rao, Ch. K.; Rao, L. B.

2018-01-01

The problem of the post-buckling response of a simply supported thin-walled beam subjected to an axial compressive load and supported by the Winkler-Pasternak foundation is studied in this paper. The strains are assumed to be small and elastic. The shear deformations and the in-plane cross-sectional deformations are assumed to be negligible. The post-buckling paths of the simply supported beam are determined for different values of the Winkler and Pasternak stiffness parameters. Bifurcation points are found.

The Versatile Elastohydrodynamics of a Free Particle near a Thin Soft Wall

Science.gov (United States)

Salez, Thomas; Saintyves, Baudouin; Mahadevan, L.

2015-03-01

We address the free motion of a buoyant particle inside a viscous fluid, in the vicinity of a thin compressible elastic wall. After discussing the main scalings, we obtain analytically the dominant drag forces within the soft lubrication approximation. By including those into the equations of motion of the particle, we establish a general governing system of three coupled nonlinear and singular differential equations, that describe the three essential motions: sedimentation, hydroplaning, and hydrospinning, through four dimensionless control parameters. Numerical integration allows us to predict a wide zoology of exotic solutions - despite the low-Reynolds feature of the flow - including: spontaneous oscillation, Magnus-like effect, enhanced sedimentation, and boomerang-like effect. We compare these predictions to experiments. The presented elementary approach could be of interest in the description of a broad variety of elastohydrodynamical phenomena, including: landslides, ageing of cartilaginous joints, and motion of a cell in a microfluidic channel or in a blood vessel.

Studies on Various Functional Properties of Titania Thin Film Developed on Glazed Ceramic Wall Tiles

Science.gov (United States)

Anil, Asha; Darshana R, Bangoria; Misra, S. N.

A sol-gel based TiO2 thin film was applied on glazed wall tiles for studying its various functional properties. Thin film was deposited by spin coating on the substrate and subjected to curing at different temperatures such as 600°C, 650, 700°C, 750°C and 800°C with 10 minutes soaking. The gel powder was characterized by FTIR, DTA/TG and XRD. Microstructure of thin film was analyzed by FESEM and EDX. Surface properties of the coatings such as gloss, colour difference, stain resistance, mineral hardness and wettability were extensively studied. The antibacterial activity of the surface of coated substrate against E. coli was also examined. The durability of the coated substrate in comparison to the uncoated was tested against alkali in accordance with ISO: 10545 (Part 13):1995 standard. FESEM images showed that thin films are dense and homogeneous. Coated substrates after firing results in lustre with high gloss, which increased from 330 to 420 GU as the curing temperature increases compared to that of uncoated one (72 GU). Coated substrate cured at 800°C shows higher mineral hardness (5 Mohs’) compared to uncoated one (4 Mohs’) and films cured at all temperatures showed stain resistance. The experimental results showed that the resistance towards alkali attack increase with increase in curing temperature and alkali resistance of sample cured at 800 °C was found to be superior compared to uncoated substrate. Contact angle of water on coated surface of substrates decreased with increase in temperature. Bacterial reduction percentages of the coated surface was 97% for sample cured at 700°C and it decreased from 97% to 87% as the curing temperature increased to 800 °C when treated with E. coli bacteria.

Piezoresistivity of mechanically drawn single-walled carbon nanotube (SWCNT) thin films-: mechanism and optimizing principle

Science.gov (United States)

Obitayo, Waris

The individual carbon nanotube (CNT) based strain sensors have been found to have excellent piezoresistive properties with a reported gauge factor (GF) of up to 3000. This GF on the other hand, has been shown to be structurally dependent on the nanotubes. In contrast, to individual CNT based strain sensors, the ensemble CNT based strain sensors have very low GFs e.g. for a single walled carbon nanotube (SWCNT) thin film strain sensor, GF is ~1. As a result, studies which are mostly numerical/analytical have revealed the dependence of piezoresistivity on key parameters like concentration, orientation, length and diameter, aspect ratio, energy barrier height and Poisson ratio of polymer matrix. The fundamental understanding of the piezoresistive mechanism in an ensemble CNT based strain sensor still remains unclear, largely due to discrepancies in the outcomes of these numerical studies. Besides, there have been little or no experimental confirmation of these studies. The goal of my PhD is to study the mechanism and the optimizing principle of a SWCNT thin film strain sensor and provide experimental validation of the numerical/analytical investigations. The dependence of the piezoresistivity on key parameters like orientation, network density, bundle diameter (effective tunneling area), and length is studied, and how one can effectively optimize the piezoresistive behavior of a SWCNT thin film strain sensors. To reach this goal, my first research accomplishment involves the study of orientation of SWCNTs and its effect on the piezoresistivity of mechanically drawn SWCNT thin film based piezoresistive sensors. Using polarized Raman spectroscopy analysis and coupled electrical-mechanical test, a quantitative relationship between the strain sensitivity and SWCNT alignment order parameter was established. As compared to randomly oriented SWCNT thin films, the one with draw ratio of 3.2 exhibited ~6x increase on the GF. My second accomplishment involves studying the

Cause analysis for elbow thinning of the secondary loop feedwater system in PWR NPP

International Nuclear Information System (INIS)

Yu Tao; Bian Chunhua; Zhang Wei; Luo Kunjie; Wang Li; Li Yan

2013-01-01

Wall thickness of some secondary system pipelines were measured on site during the refueling outages in March 2012. Wall thinning happened in some components of APA system. This paper focused on the cause analysis of an elbow with that phenomenon. Wall thickness was carefully measured in laboratory using ultrasonic thickness meter and found that wall thinning happened nearly all elbows including two abnormal thinning regions. Analytical research was conducted using ICP, stereo microscope, SEM, XRD, ANSYS. The result shows that the cause of wall thinning is flow accelerated corrosion. Based on the analysis result and international research progress, this paper makes some suggestions to avoid and alleviate FAC in the secondary system. (authors)

Simultaneous measurement of instantaneous heart rate and chest wall plethysmography in short-term, metronome guided heart rate variability studies: suitability for assessment of autonomic dysfunction.

Science.gov (United States)

Perring, S; Jones, E

2003-08-01

Instantaneous heart rate and chest wall motion were measured using a 3-lead ECG and an air pressure chest wall plethysmography system. Chest wall plethysmography traces were found to accurately represent the breathing pattern as measured by spirometry (average correlation coefficient 0.944); though no attempt was made to calibrate plethysmography voltage output to tidal volume. Simultaneous measurements of heart rate and chest wall motion were made for short periods under metronome guided breathing at 6 breaths per minute. The average peak to trough heart rate change per breath cycle (AVEMAX) and maximum correlation between heart rate and breathing cycle (HRBRCORR) were measured. Studies of 44 normal volunteers indicated clear inverse correlation of heart rate variability parameters with age (AVEMAX R = -0.502, P < 0.001) but no significant change in HRBRCORR with age (R = -0.115). Comparison of normal volunteers with diabetics with no history of symptoms associated with autonomic failure indicated significant lower heart rate variability in diabetics (P = 0.005 for AVEMAX) and significantly worse correlation between heart rate and breathing (P < 0.001 for HRBRCORR). Simultaneous measurement of heart rate and breathing offers the possibility of more sensitive diagnosis of autonomic failure in a simple bedside test and gives further insight into the nature of cardio-ventilatory coupling.

Mechanosensation Dynamically Coordinates Polar Growth and Cell Wall Assembly to Promote Cell Survival.

Science.gov (United States)

Davì, Valeria; Tanimoto, Hirokazu; Ershov, Dmitry; Haupt, Armin; De Belly, Henry; Le Borgne, Rémi; Couturier, Etienne; Boudaoud, Arezki; Minc, Nicolas

2018-04-23

How growing cells cope with size expansion while ensuring mechanical integrity is not known. In walled cells, such as those of microbes and plants, growth and viability are both supported by a thin and rigid encasing cell wall (CW). We deciphered the dynamic mechanisms controlling wall surface assembly during cell growth, using a sub-resolution microscopy approach to monitor CW thickness in live rod-shaped fission yeast cells. We found that polar cell growth yielded wall thinning and that thickness negatively influenced growth. Thickness at growing tips exhibited a fluctuating behavior with thickening phases followed by thinning phases, indicative of a delayed feedback promoting thickness homeostasis. This feedback was mediated by mechanosensing through the CW integrity pathway, which probes strain in the wall to adjust synthase localization and activity to surface growth. Mutants defective in thickness homeostasis lysed by rupturing the wall, demonstrating its pivotal role for walled cell survival. Copyright © 2018 Elsevier Inc. All rights reserved.

Molecularly ordered aluminum tris-(8-hydroxyquinoline) thin films grown by hot-wall deposition

Energy Technology Data Exchange (ETDEWEB)

Tapponnier, A. [Nonlinear Optics Laboratory, Institute of Quantum Electronics, Swiss Federal Institute of Technology Zuerich (ETH), CH-8093 Zurich (Switzerland)]. E-mail: axelle@phys.ethz.ch; Khan, R.U.A. [Nonlinear Optics Laboratory, Institute of Quantum Electronics, Swiss Federal Institute of Technology Zuerich (ETH), CH-8093 Zurich (Switzerland); Marcolli, C. [Institute of Atmospheric and Climate Sciences, Swiss Federal Institute of Technology Zuerich (ETH), CH-8092 Zurich (Switzerland); Guenter, P. [Nonlinear Optics Laboratory, Institute of Quantum Electronics, Swiss Federal Institute of Technology Zuerich (ETH), CH-8093 Zurich (Switzerland)

2007-01-22

We report on the growth and microstructural analysis of molecularly ordered thin film layers of aluminum tris-(8-hydroxyquinoline) (Alq{sub 3}) by hot-wall deposition onto amorphous glass substrates. Using transmission electron microscopy (TEM), ordering on a scale of 100 nm was observed. Raman measurements of these films indicated that they corresponded to the {alpha}-polymorph of crystalline Alq{sub 3}, and photoluminescence measurements exhibited a single broad peak centered at 500 nm, which is also consistent with the {alpha}-form. As a comparison, we deposited films of Alq3 using organic molecular beam deposition (OMBD), which exhibited no molecular ordering from the TEM studies. For these films, strong point-to-point variations in the Raman spectrum, and the existence of a double peak in the photoluminescence at 500 and 522 nm were observed. These measurements indicate that the OMBD films possess a mixture of both {alpha} and amorphous phases.

Effect of load eccentricity on the buckling of thin-walled laminated C-columns

Science.gov (United States)

Wysmulski, Pawel; Teter, Andrzej; Debski, Hubert

2018-01-01

The study investigates the behaviour of short, thin-walled laminated C-columns under eccentric compression. The tested columns are simple-supported. The effect of load inaccuracy on the critical and post-critical (local buckling) states is examined. A numerical analysis by the finite element method and experimental tests on a test stand are performed. The samples were produced from a carbon-epoxy prepreg by the autoclave technique. The experimental tests rest on the assumption that compressive loads are 1.5 higher than the theoretical critical force. Numerical modelling is performed using the commercial software package ABAQUS®. The critical load is determined by solving an eigen problem using the Subspace algorithm. The experimental critical loads are determined based on post-buckling paths. The numerical and experimental results show high agreement, thus demonstrating a significant effect of load inaccuracy on the critical load corresponding to the column's local buckling.

Electronmicroscopical evaluation of short-term nerve regeneration through a thin-walled biodegradable poly(DLLA-epsilon-CL) nerve guide filled with modified denatured muscle tissue

NARCIS (Netherlands)

Meek, MF; Robinson, PH; Stokroos, [No Value; Blaauw, EH; Kors, G; den Dunnen, WFA

The aim of this study was to evaluate short-term peripheral nerve regeneration across a 15-mm gap in the sciatic nerve of the rat, using a thin-walled biodegradable poly(DL-lactide-epsilon -caprolactone) nerve guide filled with modified denatured muscle tissue (MDMT). The evaluation was performed

Multiple, thin-walled cysts are one of the HRCT features of airspace enlargement with fibrosis

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Yasutaka, E-mail: yasuyasu@omiya.jichi.ac.jp [Division of Diagnostic Pathology, Saitama Prefectural Cardiovascular and Respiratory Center, 1696 Itai, Kumagaya City, Saitama 360-0105 (Japan); Division of Pulmonary Medicine, Clinical Department of Internal Medicine, Jichi Medical University, Saitama Medical Center, Amanuma-cho, Omiya City, Saitama 330-8503 (Japan); Kawabata, Yoshinori [Division of Diagnostic Pathology, Saitama Prefectural Cardiovascular and Respiratory Center, 1696 Itai, Kumagaya City, Saitama 360-0105 (Japan); Kanauchi, Tetsu [Department of Radiology, Saitama Prefectural Cardiovascular and Respiratory Center, 1696 Itai, Kumagaya City, Saitama 360-0105 (Japan); Hoshi, Eishin [Department of Thoracic Surgery, Saitama Prefectural Cardiovascular and Respiratory Center, 1696 Itai, Kumagaya City, Saitama 360-0105 (Japan); Kurashima, Kazuyoshi [Department of Pulmonary Medicine, Saitama Prefectural Cardiovascular and Respiratory Center, 1696 Itai, Kumagaya City, Saitama 360-0105 (Japan); Koyama, Shinichiro [Division of Pulmonary Medicine, Clinical Department of Internal Medicine, Jichi Medical University, Saitama Medical Center, Amanuma-cho, Omiya City, Saitama 330-8503 (Japan); Colby, Thomas V. [Department of Laboratory Medicine and Pathology, Mayo Clinic Scottsdale, Scottsdale, AZ 85259 (United States)

2015-05-15

Highlights: • High resolution computed tomography (HRCT) findings of airspace enlargement with fibrosis (AEF), recently identified as a smoking related change. • Investigation was in 35 smokers. • They underwent lobectomy for lung cancer with pathological confirmation of AEF. • Multiple, thin-walled cysts are one of the HRCT features of AEF. - Abstract: Purpose: Airspace enlargement with fibrosis (AEF) has been identified pathologically as a smoking related change. We sought to identify the HRCT findings of AEF and search for distinguishing features from honeycombing. Materials and methods: 50 patients (47 males; mean age 69) were evaluated. All had undergone lobectomy for lung cancer and had confirmed AEF and/or usual interstitial pneumonia (UIP) by pathological evaluation. HRCT findings were first evaluated preresection for resected lobes, and then correlated with the subsequent pathological findings in the resection specimens. Three groups were devised: one with AEF alone to determine the HRCT findings of AEF, a second with AEF and UIP and third with UIP alone. HRCT features of AEF and honeycombing were compared. Results: There were 11 patients (10 male; mean age 69) with AEF alone, 24 patients (22 male; mean age 69) with AEF and UIP, and 15 patients (15 male; mean age 68) with UIP alone. The HRCT on the AEF alone showed subpleural (but not abutting the pleura) multiple thin-walled cysts (MTWCs) in 7 and reticular opacities in 3. The HRCT in AEF and UIP showed MTWCs in 10, reticular opacities in 17; and honeycombing in 5. Among these 35 patients with the pathological finding of AEF (with or without UIP), 17 showed MTWCs. The maximum cyst wall thickness of MTWCs (mean 0.81 mm) was significantly thinner than that of honeycombing (mean 1.56 mm). MTWCs did not locate in lung base and was distant from the pleura. HRCT findings correlated with gross findings on both cysts and honeycombing. No MTWCs were seen in the 15 patients with UIP, 8 of 15 had

Multiple, thin-walled cysts are one of the HRCT features of airspace enlargement with fibrosis

International Nuclear Information System (INIS)

Watanabe, Yasutaka; Kawabata, Yoshinori; Kanauchi, Tetsu; Hoshi, Eishin; Kurashima, Kazuyoshi; Koyama, Shinichiro; Colby, Thomas V.

2015-01-01

Highlights: • High resolution computed tomography (HRCT) findings of airspace enlargement with fibrosis (AEF), recently identified as a smoking related change. • Investigation was in 35 smokers. • They underwent lobectomy for lung cancer with pathological confirmation of AEF. • Multiple, thin-walled cysts are one of the HRCT features of AEF. - Abstract: Purpose: Airspace enlargement with fibrosis (AEF) has been identified pathologically as a smoking related change. We sought to identify the HRCT findings of AEF and search for distinguishing features from honeycombing. Materials and methods: 50 patients (47 males; mean age 69) were evaluated. All had undergone lobectomy for lung cancer and had confirmed AEF and/or usual interstitial pneumonia (UIP) by pathological evaluation. HRCT findings were first evaluated preresection for resected lobes, and then correlated with the subsequent pathological findings in the resection specimens. Three groups were devised: one with AEF alone to determine the HRCT findings of AEF, a second with AEF and UIP and third with UIP alone. HRCT features of AEF and honeycombing were compared. Results: There were 11 patients (10 male; mean age 69) with AEF alone, 24 patients (22 male; mean age 69) with AEF and UIP, and 15 patients (15 male; mean age 68) with UIP alone. The HRCT on the AEF alone showed subpleural (but not abutting the pleura) multiple thin-walled cysts (MTWCs) in 7 and reticular opacities in 3. The HRCT in AEF and UIP showed MTWCs in 10, reticular opacities in 17; and honeycombing in 5. Among these 35 patients with the pathological finding of AEF (with or without UIP), 17 showed MTWCs. The maximum cyst wall thickness of MTWCs (mean 0.81 mm) was significantly thinner than that of honeycombing (mean 1.56 mm). MTWCs did not locate in lung base and was distant from the pleura. HRCT findings correlated with gross findings on both cysts and honeycombing. No MTWCs were seen in the 15 patients with UIP, 8 of 15 had

Investigation of Mild Steel Thin-Wall Tubes in Unfilled and Foam-Filled Triangle, Square, and Hexagonal Cross Sections Under Compression Load

Science.gov (United States)

Rajak, Dipen Kumar; Kumaraswamidhas, L. A.; Das, S.

2018-02-01

This study has examined proposed structures with mild steel-reinforced LM30 aluminum (Al) alloy having diversely unfilled and 10 wt.% SiCp composite foam-filled tubes for improving axial compression performance. This class of material has novel physical, mechanical, and electrical properties along with low density. In the present experiment, Al alloy foams were prepared by the melt route technique using metal hydride powder as a foaming agent. Crash energy phenomena for diverse unfilled and foam-filled in mild steel thin-wall tubes (triangular, square and hexagonal) were studied as well. Compression deformation investigation was conducted at strain rates of 0.001-0.1/s for evaluating specific energy absorption (SEA) under axial loading conditions. The results were examined to measure plateau stress, maximum densification strain, and deformation mechanism of the materials. Specific energy absorption and total energy absorption capacities of the unfilled and filled sections were determined from the compressive stress-strain curves, which were then compared with each other.

Thin chest wall is an independent risk factor for the development of pneumothorax after chest tube removal.

Science.gov (United States)

Anand, Rahul J; Whelan, James F; Ferrada, Paula; Duane, Therese M; Malhotra, Ajai K; Aboutanos, Michel B; Ivatury, Rao R

2012-04-01

The factors contributing to the development of pneumothorax after removal of chest tube thoracostomy are not fully understood. We hypothesized that development of post pull pneumothorax (PPP) after chest tube removal would be significantly lower in those patients with thicker chest walls, due to the "protective" layer of adipose tissue. All patients on our trauma service who underwent chest tube thoracostomy from July 2010 to February 2011 were retrospectively reviewed. Patient age, mechanism of trauma, and chest Abbreviated Injury Scale score were analyzed. Thoracic CTs were reviewed to ascertain chest wall thickness (CW). Thickness was measured at the level of the nipple at the midaxillary line, as perpendicular distance between skin and pleural cavity. Chest X-ray reports from immediately prior and after chest tube removal were reviewed for interval development of PPP. Data are presented as average ± standard deviation. Ninety-one chest tubes were inserted into 81 patients. Patients who died before chest tube removal (n = 11), or those without thoracic CT scans (n = 13) were excluded. PPP occurred in 29.9 per cent of chest tube removals (20/67). When PPP was encountered, repeat chest tube was necessary in 20 per cent of cases (4/20). After univariate analysis, younger age, penetrating mechanism, and thin chest wall were found to be significant risk factors for development of PPP. Chest Abbreviated Injury Scale score was similar in both groups. Logistic regression showed only chest wall thickness to be an independent risk factor for development of PPP.

Treatment of thin stillage in a high-rate anaerobic fluidized bed bioreactor (AFBR).

Science.gov (United States)

Andalib, Mehran; Hafez, Hisham; Elbeshbishy, Elsayed; Nakhla, George; Zhu, Jesse

2012-10-01

The primary objective of this work was to investigate the treatability of thin stillage as a by-product of bioethanol production plants using an anaerobic fluidized bed bioreactor (AFBR) employing zeolite with average diameter of (d(m)) of 425-610 μm and specific surface area (SSA) of 26.5m(2)/g as the carrier media. Despite the very high strength of thin stillage with chemical oxygen demand of 130,000 mg TCOD/L and suspended solids of 47,000 mg TSS/L, the AFBR showed up to 88% TCOD and 78% TSS removal at very high organic and solids loading rates (OLR and SLR) of 29 kg COD/m(3)d and 10.5 kg TSS/m(3)d respectively and hydraulic retention time (HRT) of 3.5 days. Methane production rates of up to 160 L/d at the steady state equivalent to 40 L(CH4)/L(thin stillage)d and biogas production rate per reactor volume of 15.8L(gas)/L(reactor)d were achieved. Copyright © 2012 Elsevier Ltd. All rights reserved.

Temporary formation of highly conducting domain walls for non-destructive read-out of ferroelectric domain-wall resistance switching memories

Science.gov (United States)

Jiang, Jun; Bai, Zi Long; Chen, Zhi Hui; He, Long; Zhang, David Wei; Zhang, Qing Hua; Shi, Jin An; Park, Min Hyuk; Scott, James F.; Hwang, Cheol Seong; Jiang, An Quan

2018-01-01

Erasable conductive domain walls in insulating ferroelectric thin films can be used for non-destructive electrical read-out of the polarization states in ferroelectric memories. Still, the domain-wall currents extracted by these devices have not yet reached the intensity and stability required to drive read-out circuits operating at high speeds. This study demonstrated non-destructive read-out of digital data stored using specific domain-wall configurations in epitaxial BiFeO3 thin films formed in mesa-geometry structures. Partially switched domains, which enable the formation of conductive walls during the read operation, spontaneously retract when the read voltage is removed, reducing the accumulation of mobile defects at the domain walls and potentially improving the device stability. Three-terminal memory devices produced 14 nA read currents at an operating voltage of 5 V, and operated up to T = 85 °C. The gap length can also be smaller than the film thickness, allowing the realization of ferroelectric memories with device dimensions far below 100 nm.

Stiff mutant genes of Phycomyces target turgor pressure and wall mechanical properties to regulate elongation growth rate

Directory of Open Access Journals (Sweden)

Joseph K. E. Ortega

2012-05-01

Full Text Available Regulation of cell growth is paramount to all living organisms. In plants, algae and fungi, regulation of expansive growth of cells is required for development and morphogenesis. Also, many sensory responses of stage IVb sporangiophores of Phycomyces blakesleeanus are produced by regulating elongation growth rate (growth responses and differential elongation growth rate (tropic responses. Stiff mutant sporangiophores exhibit diminished tropic responses and are found to be defective in at least four genes; madD, madE, madF and madG. Prior experimental research suggests that the defective genes affect growth regulation, but this was not verified. All the growth of the single-celled stalk of the stage IVb sporangiophore occurs in a short region termed the growth zone. Prior experimental and theoretical research indicates that elongation growth rate of the stage IVb sporangiophore can be regulated by controlling the cell wall mechanical properties within the growth zone and the magnitude of the turgor pressure. A quantitative biophysical model for elongation growth rate is required to elucidate the relationship between wall mechanical properties and turgor pressure during growth regulation. In this study, it is hypothesized that the mechanical properties of the wall within the growth zone of stiff mutant sporangiophores are different compared to wild type. A biophysical equation for elongation growth rate is derived for fungal and plant cells with a growth zone. Two strains of stiff mutants are studied, C149 madD120 (- and C216 geo- (-. Experimental results demonstrate that turgor pressure is larger but irreversible deformation rates of the wall within the growth zone and growth zone length are smaller for stiff mutant sporangiophores compared to wild type. These findings explain the diminished tropic responses of the stiff mutant sporangiophores and suggest that the defective genes affect the amount of wall-building material delivered to the inner

The reliability of finite element analysis results of the low impact test in predicting the energy absorption performance of thin-walled structures

Energy Technology Data Exchange (ETDEWEB)

Alipour, R.; Nejadx, Farokhi A.; Izman, S. [Universiti Teknologi Malaysia, Johor Bahru (Malaysia)

2015-05-15

The application of dual phase steels (DPS) such as DP600 in the form of thin-walled structure in automotive components is being continuously increased as vehicle designers utilize modern steel grades and low weight structures to improve structural performance, make automotive light and reinforce crash performance. Preventing cost enhancement of broad investigations in this area can be gained by using computers in structural analysis in order to substitute lots of experiments with finite element analysis (FEA). Nevertheless, it necessitates to be certified that selected method including element type and solution methodology is capable of predicting real condition. In this paper, numerical and experimental studies are done to specify the effect of element type selection and solution methodology on the results of finite element analysis in order to investigate the energy absorption behavior of a DP600 thin-walled structure with three different geometries under a low impact loading. The outcomes indicated the combination of implicit method and solid elements is in better agreement with the experiments. In addition, using a combination of shell element types with implicit method reduces the time of simulation remarkably, although the error of results compared to the experiments increased to some extent.

Optimal Shakedown of the Thin-Wall Metal Structures Under Strength and Stiffness Constraints

Directory of Open Access Journals (Sweden)

Alawdin Piotr

2017-06-01

Full Text Available Classical optimization problems of metal structures confined mainly with 1st class cross-sections. But in practice it is common to use the cross-sections of higher classes. In this paper, a new mathematical model for described shakedown optimization problem for metal structures, which elements are designed from 1st to 4th class cross-sections, under variable quasi-static loads is presented. The features of limited plastic redistribution of forces in the structure with thin-walled elements there are taken into account. Authors assume the elastic-plastic flexural buckling in one plane without lateral torsional buckling behavior of members. Design formulae for Methods 1 and 2 for members are analyzed. Structures stiffness constrains are also incorporated in order to satisfy the limit serviceability state requirements. With the help of mathematical programming theory and extreme principles the structure optimization algorithm is developed and justified with the numerical experiment for the metal plane frames.

Axial Crushing Behaviors of Thin-Walled Corrugated and Circular Tubes - A Comparative Study

Science.gov (United States)

Reyaz-Ur-Rahim, Mohd.; Bharti, P. K.; Umer, Afaque

2017-10-01

With the help of finite element analysis, this research paper deals with the energy absorption and collapse behavior with different corrugated section geometries of hollow tubes made of aluminum alloy 6060-T4. Literature available experimental data were used to validate the numerical models of the structures investigated. Based on the results available for symmetric crushing of circular tubes, models were developed to investigate corrugated thin-walled structures behavior. To study the collapse mechanism and energy absorbing ability in axial compression, the simulation was carried in ABAQUS /EXPLICIT code. In the simulation part, specimens were prepared and axially crushed to one-fourth length of the tube and the energy diagram of crushing force versus axial displacement is shown. The effect of various parameters such as pitch, mean diameter, corrugation, amplitude, the thickness is demonstrated with the help of diagrams. The overall result shows that the corrugated section geometry could be a good alternative to the conventional tubes.

STUDY OF STATIC AND DYNAMIC STABILITY OF THIN-WALLED BARS EXCITED BY PERIODICAL AXIAL EXTERNAL FORCES.

Directory of Open Access Journals (Sweden)

Minodora Maria PASĂRE

2010-10-01

Full Text Available In these paper, starting from the relations for the displacements and spinning the transversal section of a bar with thin walls of sections opened expressed by the corresponding influence functions and introducing the components of the exterior forces distributed and the moments of the exterior forces distributed due to the inertia forces, the exciting axial forces together with the following effect of these and of the reaction forces of the elastic environment for leaning it may reach to the system of the equations of parametric vibrations under the form of three integral equation These equations may serve for the study of vibrations of the bars, to study the static stability and to study the dynamic stability

Selective Deposition and Alignment of Single-Walled Carbon Nanotubes Assisted by Dielectrophoresis: From Thin Films to Individual Nanotubes

Science.gov (United States)

Li, Pengfei; Xue, Wei

2010-06-01

Dielectrophoresis has been used in the controlled deposition of single-walled carbon nanotubes (SWNTs) with the focus on the alignment of nanotube thin films and their applications in the last decade. In this paper, we extend the research from the selective deposition of SWNT thin films to the alignment of small nanotube bundles and individual nanotubes. Electrodes with “teeth”-like patterns are fabricated to study the influence of the electrode width on the deposition and alignment of SWNTs. The entire fabrication process is compatible with optical lithography-based techniques. Therefore, the fabrication cost is low, and the resulting devices are inexpensive. A series of SWNT solutions is prepared with concentrations ranging from 0.0125 to 0.2 mg/ml. The alignment of SWNT thin films, small bundles, and individual nanotubes is achieved under the optimized experimental conditions. The electrical properties of these samples are characterized; the linear current-voltage plots prove that the aligned SWNTs are mainly metallic nanotubes. The microscopy inspection of the samples demonstrates that the alignment of small nanotube bundles and individual nanotubes can only be achieved using narrow electrodes and low-concentration solutions. Our investigation shows that it is possible to deposit a controlled amount of SWNTs in desirable locations using dielectrophoresis.

Selective Deposition and Alignment of Single-Walled Carbon Nanotubes Assisted by Dielectrophoresis: From Thin Films to Individual Nanotubes

Directory of Open Access Journals (Sweden)

Li Pengfei

2010-01-01

Full Text Available Abstract Dielectrophoresis has been used in the controlled deposition of single-walled carbon nanotubes (SWNTs with the focus on the alignment of nanotube thin films and their applications in the last decade. In this paper, we extend the research from the selective deposition of SWNT thin films to the alignment of small nanotube bundles and individual nanotubes. Electrodes with “teeth”-like patterns are fabricated to study the influence of the electrode width on the deposition and alignment of SWNTs. The entire fabrication process is compatible with optical lithography-based techniques. Therefore, the fabrication cost is low, and the resulting devices are inexpensive. A series of SWNT solutions is prepared with concentrations ranging from 0.0125 to 0.2 mg/ml. The alignment of SWNT thin films, small bundles, and individual nanotubes is achieved under the optimized experimental conditions. The electrical properties of these samples are characterized; the linear current–voltage plots prove that the aligned SWNTs are mainly metallic nanotubes. The microscopy inspection of the samples demonstrates that the alignment of small nanotube bundles and individual nanotubes can only be achieved using narrow electrodes and low-concentration solutions. Our investigation shows that it is possible to deposit a controlled amount of SWNTs in desirable locations using dielectrophoresis.

Influence of Clay Platelet Spacing on Oxygen Permeability of Thin Film Assemblies

Science.gov (United States)

Priolo, Morgan; Gamboa, Daniel; Grunlan, Jaime

2010-03-01

Thin films of anionic natural montmorrilonite clay and various polyelectrolytes have been produced by alternately dipping a plastic substrate into dilute aqueous mixtures containing each ingredient in an effort to show the influence of clay platelet spacing on thin film permeability. After polymer-clay layers have been sequentially deposited, the resulting transparent films exhibit a brick wall nanostructure comprised of completely exfoliated clay bricks in polymeric mortar. This brick wall forms an extremely tortuous path for a molecule to traverse, creating channels perpendicular to the concentration gradient that increase the molecule's diffusion length and delay its transmission. To a first approximation, greater clay spacing (i.e., reduced clay concentration) produces greater oxygen barrier. Oxygen transmission rates below 0.005 cm^3/m^2.day have been achieved for films with only eight clay layers (total thickness of only 200 nm). With optical transparencies greater than 86% and the ability to be microwaved, these thin film composites are good candidates for flexible electronics packaging and foil replacement for food.

Influence of Mn contents in 0Cr18Ni10Ti thin wall stainless steel tube on TIG girth weld quality

Science.gov (United States)

Liu, Bo

2017-03-01

Three kinds of cold worked 0Cr18Ni10Ti thin wall stainless steel tubes with the manganese contents of 1.27%, 1.35% and 1.44% and the cold worked 0Cr18Ni10Ti stainless steel end plug with manganese content of 1.35% were used for TIG girth welding in the present investigation. The effect of different manganese contents in stainless steel tube on weld quality was studied. The results showed that under the same welding conditions, the metallographic performance of the girth weld for the thin wall stainless steel tube with the manganese element content 1.44% welded with end plug was the best. Under the appropriate welding conditions, the quality of the girth weld increased with the increase of the manganese content till 1.44%. It was found that in the case of the Mn content of 1.44%, and under the proper welding condition the welding defects, such as welding cracks were effectively avoided, and the qualified weld penetration can be obtained.. It is concluded that the appropriate increase of the manganese content can significantly improve the TIG girth weld quality of the cold worked 0Cr18Ni10Ti stainless steel tube.

High-performance thin-film-transistors based on semiconducting-enriched single-walled carbon nanotubes processed by electrical-breakdown strategy

Energy Technology Data Exchange (ETDEWEB)

Aïssa, B., E-mail: aissab@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650, boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Qatar Environment and Energy Research Institute (QEERI), Qatar Foundation, P.O. Box 5825, Doha (Qatar); Nedil, M. [Telebec Wireless Underground Communication Laboratory, UQAT, 675, 1" è" r" e Avenue, Val d’Or, Québec J9P 1Y3 (Canada); Habib, M.A. [Computer Sciences and Engineering Department, Yanbu University College, P.O. Box 30031 (Saudi Arabia); Abdul-Hafidh, E.H. [High Energy Physics Department, Yanbu University College, P.O. Box 30031 (Saudi Arabia); Rosei, F. [Centre Énergie, Matériaux et Télécommunications, INRS, 1650, boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada)

2015-02-15

Highlights: • We selectively burn metallic single wall carbon nanotubes (SWCNT) by electrical breakdown. • We successfully achieve a semiconducting enriched-SWCNT in TFT configuration. • High performance, like On/Off of 10{sup 5} and a subthreshold swing of 165 mV/decades were obtained. • After PMMA coating, the SWCNT–TFTs were found stables for more than 4 months. - Abstract: Over the past two decades, among remarkable variety of nanomaterials, single-walled carbon nanotubes (SWCNTs) remain the most intriguing and uniquely well suited materials for applications in high-performance electronics. The most advanced technologies require the ability to form purely semiconducting SWCNTs. Here, we report on our strategy based on the well known progressive electrical breakdown process that offer this capability and serves as highly efficient means for selectively removing metallic carbon nanotubes from electronically heterogeneous random networks, deposited on silicon substrates in a thin film transistor (TFT) configuration. We demonstrate the successful achievement of semiconducting enriched-SWCNT networks in TFT scheme that reach On/Off switching ratios of ∼100,000, on-conductance of 20 μS, and a subthreshold swing of less than 165 mV/decades. The obtained TFT devices were then protected with thin film poly(methyl methacrylate) (PMMA) to keep the percolation level of the SWCNTs network spatially and temporally stable, while protecting it from atmosphere exchanges. TFT devices were found to be air-stable and maintained their excellent characteristics in ambient atmosphere for more than 4 months. This approach could work as a platform for future nanotube-based nanoelectronics.

Review of industry efforts to manage pressurized water reactor feedwater nozzle, piping, and feedring cracking and wall thinning

Energy Technology Data Exchange (ETDEWEB)

Shah, V.N.; Ware, A.G.; Porter, A.M.

1997-03-01

This report presents a review of nuclear industry efforts to manage thermal fatigue, flow-accelerated corrosion, and water hammer damage to pressurized water reactor (PWR) feedwater nozzles, piping, and feedrings. The review includes an evaluation of design modifications, operating procedure changes, augmented inspection and monitoring programs, and mitigation, repair and replacement activities. Four actions were taken: (a) review of field experience to identify trends of operating events, (b) review of technical literature, (c) visits to PWR plants and a PWR vendor, and (d) solicitation of information from 8 other countries. Assessment of field experience is that licensees have apparently taken sufficient action to minimize feedwater nozzle cracking caused by thermal fatigue and wall thinning of J-tubes and feedwater piping. Specific industry actions to minimize the wall-thinning in feedrings and thermal sleeves were not found, but visual inspection and necessary repairs are being performed. Assessment of field experience indicates that licensees have taken sufficient action to minimize steam generator water hammer in both top-feed and preheat steam generators. Industry efforts to minimize multiple check valve failures that have allowed backflow of steam from a steam generator and have played a major role in several steam generator water hammer events were not evaluated. A major finding of this review is that analysis, inspection, monitoring, mitigation, and replacement techniques have been developed for managing thermal fatigue and flow-accelerated corrosion damage to feedwater nozzles, piping, and feedrings. Adequate training and appropriate applications of these techniques would ensure effective management of this damage.

Review of industry efforts to manage pressurized water reactor feedwater nozzle, piping, and feedring cracking and wall thinning

International Nuclear Information System (INIS)

Shah, V.N.; Ware, A.G.; Porter, A.M.

1997-03-01

This report presents a review of nuclear industry efforts to manage thermal fatigue, flow-accelerated corrosion, and water hammer damage to pressurized water reactor (PWR) feedwater nozzles, piping, and feedrings. The review includes an evaluation of design modifications, operating procedure changes, augmented inspection and monitoring programs, and mitigation, repair and replacement activities. Four actions were taken: (a) review of field experience to identify trends of operating events, (b) review of technical literature, (c) visits to PWR plants and a PWR vendor, and (d) solicitation of information from 8 other countries. Assessment of field experience is that licensees have apparently taken sufficient action to minimize feedwater nozzle cracking caused by thermal fatigue and wall thinning of J-tubes and feedwater piping. Specific industry actions to minimize the wall-thinning in feedrings and thermal sleeves were not found, but visual inspection and necessary repairs are being performed. Assessment of field experience indicates that licensees have taken sufficient action to minimize steam generator water hammer in both top-feed and preheat steam generators. Industry efforts to minimize multiple check valve failures that have allowed backflow of steam from a steam generator and have played a major role in several steam generator water hammer events were not evaluated. A major finding of this review is that analysis, inspection, monitoring, mitigation, and replacement techniques have been developed for managing thermal fatigue and flow-accelerated corrosion damage to feedwater nozzles, piping, and feedrings. Adequate training and appropriate applications of these techniques would ensure effective management of this damage

Direct numerical simulation of an isothermal reacting turbulent wall-jet

Science.gov (United States)

Pouransari, Zeinab; Brethouwer, Geert; Johansson, Arne V.

2011-08-01

In the present investigation, Direct Numerical Simulation (DNS) is used to study a binary irreversible and isothermal reaction in a plane turbulent wall-jet. The flow is compressible and a single-step global reaction between an oxidizer and a fuel species is solved. The inlet based Reynolds, Schmidt, and Mach numbers of the wall-jet are Re = 2000, Sc = 0.72, and M = 0.5, respectively, and a constant coflow velocity is applied above the jet. At the inlet, fuel and oxidizer enter the domain separately in a non-premixed manner. The turbulent structures of the velocity field show the common streaky patterns near the wall, while a somewhat patchy or spotty pattern is observed for the scalars and the reaction rate fluctuations in the near-wall region. The reaction mainly occurs in the upper shear layer in thin highly convoluted reaction zones, but it also takes place close to the wall. Analysis of turbulence and reaction statistics confirms the observations in the instantaneous snapshots, regarding the intermittent character of the reaction rate near the wall. A detailed study of the probability density functions of the reacting scalars and comparison to that of the passive scalar throughout the domain reveals the significance of the reaction influence as well as the wall effects on the scalar distributions. The higher order moments of both the velocities and the scalar concentrations are analyzed and show a satisfactory agreement with experiments. The simulations show that the reaction can both enhance and reduce the dissipation of fuel scalar, since there are two competing effects; on the one hand, the reaction causes sharper scalar gradients and thus a higher dissipation rate, on the other hand, the reaction consumes the fuel scalar thereby reducing the scalar dissipation.

Oxygenation of the traditional and thin-walled MT-YBCO in flowing oxygen and under high evaluated oxygen pressure

International Nuclear Information System (INIS)

Prikhna, Tatiana; Chaud, Xavier; Gawalek, Wolfgang; Rabier, Jaques; Savchuk, Yaroslav; Joulain, Anne; Vlasenko, Andrey; Moshchil, Viktor; Sergienko, Nina; Dub, Sergey; Melnikov, Vladimir; Litzkendorf, Doris; Habisreuther, Tobias; Sverdun, Vladimir

2007-01-01

The high pressure-high temperature oxygenation of thin-walled MT-YBCO (with artificially produced holes) allows decreasing the amount of macrocracks and increasing j c of the material. The MT-YBCO produced from Y123 and Y211 in the fields higher than 2 T showed higher j c in the ab-planes and lower j c in the c-direction than the MT-YBCO manufactured from Y123 and Y 2 O 3 and can be explained by the difference in twin and microcrack density that in turn can be affected by the difference in Y211 phase distribution

Morphological Evolution of Gyroid-Forming Block Copolymer Thin Films with Varying Solvent Evaporation Rate.

Science.gov (United States)

Wu, Yi-Hsiu; Lo, Ting-Ya; She, Ming-Shiuan; Ho, Rong-Ming

2015-08-05

In this study, we aim to examine the morphological evolution of block copolymer (BCP) nanostructured thin films through solvent evaporation at different rates for solvent swollen polystyrene-block-poly(l-lactide) (PS-PLLA). Interesting phase transitions from disorder to perpendicular cylinder and then gyroid can be found while using a partially selective solvent for PS to swell PS-PLLA thin film followed by solvent evaporation. During the transitions, gyroid-forming BCP thin film with characteristic crystallographic planes of (111)G, (110)G, and (211)G parallel to air surface can be observed, and will gradually transform into coexisting (110)G and (211)G planes, and finally transforms to (211)G plane due to the preferential segregation of constituted block to the surface (i.e., the thermodynamic origin for self-assembly) that affects the relative amount of each component at the air surface. With the decrease on the evaporation rate, the disorder phase will transform to parallel cylinder and then directly to (211)G without transition to perpendicular cylinder phase. Most importantly, the morphological evolution of PS-PLLA thin films is strongly dependent upon the solvent removal rate only in the initial stage of the evaporation process due to the anisotropy of cylinder structure. Once the morphology is transformed back to the isotropic gyroid structure after long evaporation, the morphological evolution will only relate to the variation of the surface composition. Similar phase transitions at the substrate can also be obtained by controlling the ratio of PLLA-OH to PS-OH homopolymers to functionalize the substrate. As a result, the fabrication of well-defined nanostructured thin films with controlled orientation can be achieved by simple swelling and deswelling with controlled evaporation rate.

Role of plasma enhanced atomic layer deposition reactor wall conditions on radical and ion substrate fluxes

Energy Technology Data Exchange (ETDEWEB)

Sowa, Mark J., E-mail: msowa@ultratech.com [Ultratech/Cambridge NanoTech, 130 Turner Street, Building 2, Waltham, Massachusetts 02453 (United States)

2014-01-15

Chamber wall conditions, such as wall temperature and film deposits, have long been known to influence plasma source performance on thin film processing equipment. Plasma physical characteristics depend on conductive/insulating properties of chamber walls. Radical fluxes depend on plasma characteristics as well as wall recombination rates, which can be wall material and temperature dependent. Variations in substrate delivery of plasma generated species (radicals, ions, etc.) impact the resulting etch or deposition process resulting in process drift. Plasma enhanced atomic layer deposition is known to depend strongly on substrate radical flux, but film properties can be influenced by other plasma generated phenomena, such as ion bombardment. In this paper, the chamber wall conditions on a plasma enhanced atomic layer deposition process are investigated. The downstream oxygen radical and ion fluxes from an inductively coupled plasma source are indirectly monitored in temperature controlled (25–190 °C) stainless steel and quartz reactors over a range of oxygen flow rates. Etch rates of a photoresist coated quartz crystal microbalance are used to study the oxygen radical flux dependence on reactor characteristics. Plasma density estimates from Langmuir probe ion saturation current measurements are used to study the ion flux dependence on reactor characteristics. Reactor temperature was not found to impact radical and ion fluxes substantially. Radical and ion fluxes were higher for quartz walls compared to stainless steel walls over all oxygen flow rates considered. The radical flux to ion flux ratio is likely to be a critical parameter for the deposition of consistent film properties. Reactor wall material, gas flow rate/pressure, and distance from the plasma source all impact the radical to ion flux ratio. These results indicate maintaining chamber wall conditions will be important for delivering consistent results from plasma enhanced atomic layer deposition

Finite element analysis of the design and manufacture of thin-walled pressure vessels used as aerosol cans

Science.gov (United States)

Abdussalam, Ragba Mohamed

Thin-walled cylinders are used extensively in the food packaging and cosmetics industries. The cost of material is a major contributor to the overall cost and so improvements in design and manufacturing processes are always being sought. Shape optimisation provides one method for such improvements. Aluminium aerosol cans are a particular form of thin-walled cylinder with a complex shape consisting of truncated cone top, parallel cylindrical section and inverted dome base. They are manufactured in one piece by a reverse-extrusion process, which produces a vessel with a variable thickness from 0.31 mm in the cylinder up to 1.31 mm in the base for a 53 mm diameter can. During manufacture, packaging and charging, they are subjected to pressure, axial and radial loads and design calculations are generally outside the British and American pressure vessel codes. 'Design-by-test' appears to be the favoured approach. However, a more rigorous approach is needed in order to optimise the designs. Finite element analysis (FEA) is a powerful tool for predicting stress, strain and displacement behaviour of components and structures. FEA is also used extensively to model manufacturing processes. In this study, elastic and elastic-plastic FEA has been used to develop a thorough understanding of the mechanisms of yielding, 'dome reversal' (an inherent safety feature, where the base suffers elastic-plastic buckling at a pressure below the burst pressure) and collapse due to internal pressure loading and how these are affected by geometry. It has also been used to study the buckling behaviour under compressive axial loading. Furthermore, numerical simulations of the extrusion process (in order to investigate the effects of tool geometry, friction coefficient and boundary conditions) have been undertaken. Experimental verification of the buckling and collapse behaviours has also been carried out and there is reasonable agreement between the experimental data and the numerical

Layer-by-layer assembly of thin film oxygen barrier

International Nuclear Information System (INIS)

Jang, Woo-Sik; Rawson, Ian; Grunlan, Jaime C.

2008-01-01

Thin films of sodium montmorillonite clay and cationic polyacrylamide were grown on a polyethylene terephthalate film using layer-by-layer assembly. After 30 clay-polymer layers are deposited, with a thickness of 571 nm, the resulting transparent film has an oxygen transmission rate (OTR) below the detection limit of commercial instrumentation ( 2 /day/atm). This low OTR, which is unprecedented for a clay-filled polymer composite, is believed to be due to a brick wall nanostructure comprised of completely exfoliated clay in polymeric mortar. With an optical transparency greater than 90% and potential for microwaveability, this thin composite is a good candidate for foil replacement in food packaging and may also be useful for flexible electronics packaging

In-situ nanomechanical study on bending characteristics of individual multi-walled carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Tsai, Ping-Chi, E-mail: pctjbenchen@yahoo.com.tw [Department of Mechanical Engineering, National Chung Cheng University, Chia-Yi 621, Taiwan (China); Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chia-Yi 621, Taiwan (China); Jeng, Yeau-Ren, E-mail: imeyrj@ccu.edu.tw [Department of Mechanical Engineering, National Chung Cheng University, Chia-Yi 621, Taiwan (China); Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chia-Yi 621, Taiwan (China)

2016-03-21

Bending characteristics of individual thin-walled carbon nanotubes (CNTs) are investigated through a novel in-situ nanoindentation in transmission electron microscopy. Unlike thick-walled CNTs, the graphitic layers of thin ones buckle into V-shaped kinks rather than Yoshimura ripples. These kinks are found to be entirely reversible without residual plastic deformation following unloading.

Transparent and flexible electrodes and supercapacitors using polyaniline/single-walled carbon nanotube composite thin films

Science.gov (United States)

Ge, Jun; Cheng, Guanghui; Chen, Liwei

2011-08-01

Large-scale transparent and flexible electronic devices have been pursued for potential applications such as those in touch sensors and display technologies. These applications require that the power source of these devices must also comply with transparent and flexible features. Here we present transparent and flexible supercapacitors assembled from polyaniline (PANI)/single-walled carbon nanotube (SWNT) composite thin film electrodes. The ultrathin, optically homogeneous and transparent, electrically conducting films of the PANI/SWNT composite show a large specific capacitance due to combined double-layer capacitance and pseudo-capacitance mechanisms. A supercapacitor assembled using electrodes with a SWNT density of 10.0 µg cm-2 and 59 wt% PANI gives a specific capacitance of 55.0 F g-1 at a current density of 2.6 A g-1, showing its possibility for transparent and flexible energy storage.

Self-Sealed Bionic Long Microchannels with Thin Walls and Designable Nanoholes Prepared by Line-Contact Capillary-Force Assembly.

Science.gov (United States)

Lao, Zhao-Xin; Hu, Yan-Lei; Pan, Deng; Wang, Ren-Yan; Zhang, Chen-Chu; Ni, Jin-Cheng; Xu, Bing; Li, Jia-Wen; Wu, Dong; Chu, Jia-Ru

2017-06-01

Long microchannels with thin walls, small width, and nanoholes or irregular shaped microgaps, which are similar to capillaries or cancerous vessels, are urgently needed to simulate the physiological activities in human body. However, the fabrication of such channels remains challenging. Here, microchannels with designable holes are manufactured by combining laser printing with line-contact capillary-force assembly. Two microwalls are first printed by femtosecond laser direct-writing, and subsequently driven to collapse into a channel by the capillary force that arises in the evaporation of developer. The channel can remain stable in solvent due to the enhanced Van der Waals' force caused by the line-contact of microwalls. Microchannels with controllable nanoholes and almost arbitrary patterns can be fabricated without any bonding or multistep processes. As-prepared microchannels, with wall thicknesses less than 1 µm, widths less than 3 µm, lengths more than 1 mm, are comparable with human capillaries. In addition, the prepared channels also exhibit the ability to steer the flow of liquid without any external pump. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-sustaining thin films as a means of reducing first wall erosion and plasma impurity influx

International Nuclear Information System (INIS)

Krauss, A.R.; Gruen, D.M.

1982-01-01

Neutral impurities ejected from Tokamak wall and limiter surfaces may travel several cm before being ionized very quickly upon entering the plasma edge. The influence of the unipolar sheath potential is exerted only within a very short distance of the surface and has no effect on neutral impurity atoms within a very short distance of the surface and has no effect on neutral impurity atoms which are subsequently ionized by charge-exchange collisions or electron impact ionization. However, secondary ions emanating from the limiter surfaces with kinetic energies less than the sheath potential will have essentially zero probability of traveling more than a few Debye lengths before being redeposited. Similarly, secondary ions originating at the first wall are redeposited as a result of the deflection produced by the magnetic field. Impurity influx resulting from sputtering would therefore be substantially reduced for surfaces which produce a very high ion/neutral ratio when sputtered. It has been previously shown that the high secondary ion yield associated with the alkali metal potassium does not apply to the bulk metal but pertains to ionic compounds and thin (mono-layer) films. Two processes are discussed as a means of producing these films in a self-sustaining manner compatible with the fusion reactor environment. (orig.)

Arterial wall mechanics as a function of heart rate: role of vascular smooth muscle

International Nuclear Information System (INIS)

Salvucci, Fernando Pablo; Schiavone, Jonathan; Craiem, Damian; Barra, Juan Gabriel

2007-01-01

Vascular wall viscoelasticity can be evaluated using a first-order lumped model. This model consists of a spring with elastic constant E and a dashpot with viscous constant η. More importantly, this viscoelastic model can be fitted in-vivo measuring arterial pressure and diameter. The aim of this work is to analyze the influence of heart rate over E and η. In two anesthetized sheep, diameter in thoracic aorta and intravascular pressure has been registered. The right atrium was connected to a programmable stimulator through a pair of pace-maker wires to produce changes in stimulation heart rate (HR) from 80 to 160 bpm. Additionally, local activation of vascular smooth muscle was induced with phenylephrine. After converting pressure and diameter signals into stress and strain respectively, E y η were calculated in control state and during muscle activation. The elastic modulus E did not present significant changes with heart rate. The viscous modulus η decreased 49% with a two-fold acceleration in heart rate from 80 to 160 bpm. However, the product η HR remained stable. The viscous modulus η increased 39% with smooth muscle activation. No significant pressure changes were registered during the experiment. The contractile action of vascular smooth muscle could contribute to increasing arterial wall viscosity. The decrease of η when HR increased might be related to smooth muscle relaxation mediated by endothelium activity, which was stimulated by flow increase. We conclude that HR can modulate arterial wall viscoelasticity through endothelium-dependent mechanisms

Application of numerical analysis technique to make up for pipe wall thinning prediction program

International Nuclear Information System (INIS)

Hwang, Kyeong Mo; Jin, Tae Eun; Park, Won; Oh, Dong Hoon

2009-01-01

Flow Accelerated Corrosion (FAC) leads to wall thinning of steel piping exposed to flowing water or wet steam. Experience has shown that FAC damage to piping at fossil and nuclear plants can lead to costly outages and repairs and can affect plant reliability and safety. CHEWORKS have been utilized in domestic nuclear plants as a predictive tool to assist FAC engineers in planning inspections and evaluating the inspection data to prevent piping failures caused by FAC. However, CHECWORKS may be occasionally left out local susceptible portions owing to predicting FAC damage by pipeline group after constructing a database for all secondary side piping in nuclear plants. This paper describes the methodologies that can complement CHECWORKS and the verifications of the CHECWORKS prediction results in terms of numerical analysis. FAC susceptible locations based on CHECWORKS for the two pipeline groups of a nuclear plant was compared with those of numerical analysis based on FLUENT.

Oxygenation of the traditional and thin-walled MT-YBCO in flowing oxygen and under high evaluated oxygen pressure

Energy Technology Data Exchange (ETDEWEB)

Prikhna, Tatiana [Institute for Superhard Materials, 2 Avtozavodskaya Street, Kiev 04074 (Ukraine)], E-mail: prikhna@iptelecom.net.ua; Chaud, Xavier [CNRS/CRETA, 25, Avenue des Martyrs BP 166, 38042 Grenoble, Cedex 9 (France); Gawalek, Wolfgang [Institut fuer Physikalische Hochtechnologie, Albert-Einstein-Strasse 9, Jena (Germany); Rabier, Jaques [Universite de Poitiers, CNRS/Lab. de Metallurgie Physique, UMR 6630 CNRS-Universite de Poitiers SP2MI, BP 30179, F-86962 Chasseneuil Futuroscope Cedex (France); Savchuk, Yaroslav [Institute for Superhard Materials, 2 Avtozavodskaya Street, Kiev 04074 (Ukraine); Joulain, Anne [Universite de Poitiers, CNRS/Lab. de Metallurgie Physique, UMR 6630 CNRS-Universite de Poitiers SP2MI, BP 30179, F-86962 Chasseneuil Futuroscope Cedex (France); Vlasenko, Andrey; Moshchil, Viktor; Sergienko, Nina; Dub, Sergey; Melnikov, Vladimir [Institute for Superhard Materials, 2 Avtozavodskaya Street, Kiev 04074 (Ukraine); Litzkendorf, Doris; Habisreuther, Tobias [Institut fuer Physikalische Hochtechnologie, Albert-Einstein-Strasse 9, Jena (Germany); Sverdun, Vladimir [Institute for Superhard Materials, 2 Avtozavodskaya Street, Kiev 04074 (Ukraine)

2007-09-01

The high pressure-high temperature oxygenation of thin-walled MT-YBCO (with artificially produced holes) allows decreasing the amount of macrocracks and increasing j{sub c} of the material. The MT-YBCO produced from Y123 and Y211 in the fields higher than 2 T showed higher j{sub c} in the ab-planes and lower j{sub c} in the c-direction than the MT-YBCO manufactured from Y123 and Y{sub 2}O{sub 3} and can be explained by the difference in twin and microcrack density that in turn can be affected by the difference in Y211 phase distribution.

Through-Metal-Wall Power Delivery and Data Transmission for Enclosed Sensors: A Review

Directory of Open Access Journals (Sweden)

Ding-Xin Yang

2015-12-01

Full Text Available The aim of this review was to assess the current viable technologies for wireless power delivery and data transmission through metal barriers. Using such technologies sensors enclosed in hermetical metal containers can be powered and communicate through exterior power sources without penetration of the metal wall for wire feed-throughs. In this review, we first discuss the significant and essential requirements for through-metal-wall power delivery and data transmission and then we: (1 describe three electromagnetic coupling based techniques reported in the literature, which include inductive coupling, capacitive coupling, and magnetic resonance coupling; (2 present a detailed review of wireless ultrasonic through-metal-wall power delivery and/or data transmission methods; (3 compare various ultrasonic through-metal-wall systems in modeling, transducer configuration and communication mode with sensors; (4 summarize the characteristics of electromagnetic-based and ultrasound-based systems, evaluate the challenges and development trends. We conclude that electromagnetic coupling methods are suitable for through thin non-ferromagnetic metal wall power delivery and data transmission at a relatively low data rate; piezoelectric transducer-based ultrasonic systems are particularly advantageous in achieving high power transfer efficiency and high data rates; the combination of more than one single technique may provide a more practical and reliable solution for long term operation.

Electrode patterning of ITO thin films by high repetition rate fiber laser

International Nuclear Information System (INIS)

Lin, H.K.; Hsu, W.C.

2014-01-01

Indium tin oxide (ITO) thin films are deposited on glass substrates using a radio frequency magnetron sputtering system. As-deposited ITO thin film was 100 nm in thickness and a transmittance of ITO film on glass substrate was 79% at 550 nm. Conductive electrodes are then patterned on the ITO films using a high repetition rate fiber laser system followed by a wet chemical etching process. The electrical, optical and structural properties of the patterned samples are evaluated by means of a four-point probe technique, spectrophotometer, X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that the samples annealed with a pulse repetition rate of 150 kHz or 400 kHz have a low sheet resistivity of 21 Ω/□ and a high optical transmittance of 90%. In addition, it is shown that a higher pulse repetition rate reduces both the residual stress and the surface roughness of the patterned specimens. Therefore, the present results suggest that a pulse repetition rate of 400 kHz represents the optimal processing condition for the patterning of crack-free ITO-coated glass substrates with good electrical and optical properties.

Electrode patterning of ITO thin films by high repetition rate fiber laser

Energy Technology Data Exchange (ETDEWEB)

Lin, H.K., E-mail: HKLin@mail.npust.edu.tw; Hsu, W.C.

2014-07-01

Indium tin oxide (ITO) thin films are deposited on glass substrates using a radio frequency magnetron sputtering system. As-deposited ITO thin film was 100 nm in thickness and a transmittance of ITO film on glass substrate was 79% at 550 nm. Conductive electrodes are then patterned on the ITO films using a high repetition rate fiber laser system followed by a wet chemical etching process. The electrical, optical and structural properties of the patterned samples are evaluated by means of a four-point probe technique, spectrophotometer, X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that the samples annealed with a pulse repetition rate of 150 kHz or 400 kHz have a low sheet resistivity of 21 Ω/□ and a high optical transmittance of 90%. In addition, it is shown that a higher pulse repetition rate reduces both the residual stress and the surface roughness of the patterned specimens. Therefore, the present results suggest that a pulse repetition rate of 400 kHz represents the optimal processing condition for the patterning of crack-free ITO-coated glass substrates with good electrical and optical properties.

Resistive Wall Mode Stability and Control in the Reversed Field Pinch

International Nuclear Information System (INIS)

Yadikin, Dmitriy

2006-03-01

Control of MHD instabilities using a conducting wall together with external magnetic fields is an important route to improved performance and reliability in fusion devices. Active control of MHD modes is of interest for both the Advanced Tokamak and the Reversed Field Pinch (RFP) configurations. A wide range of unstable, current driven MHD modes is present in the RFP. An ideally conducting wall facing the plasma can in principle provide stabilization to these modes. However, a real, resistive wall characterized by a wall field diffusion time, cannot stabilize the ideal MHD modes unless they rotate with Alfvenic velocity, which is usually not the case. With a resistive wall, the ideal modes are converted into resistive wall modes (RWM) with growth rates comparable to the inverse wall time. Resistive wall modes have been studied in the EXTRAP T2R thin shell RFP device. Growth rates have been measured and found in agreement with linear MHD stability calculations. An advanced system for active control has been developed and installed on the EXTRAP T2R device. The system includes an array of 128 active saddle coils, fully covering the torus surface. Experiments on EXTRAP T2R have for the first time demonstrated simultaneous active suppression of multiple independent RWMs. In experiments with a partial array, coupling of different modes due to the limited number of feedback coils has been observed, in agreement with theory. Different feedback strategies, such as the intelligent shell, the rotating shell, and mode control have been studied. Further, feedback operation with different types of magnetic field sensors, measuring either the radial or the toroidal field components have been compared

Determination of exhalation rate of radon from walls and indoor radon by CR-39 detectors

International Nuclear Information System (INIS)

Vasidov, A.; Tillaev, T.S.

2007-01-01

Full text: The knowledge of true value exhalation rate of radon gas from building materials represents scientific and practical interest in environmental radiation protection. This point of view in the paper exhalation rate of radon gas from building materials and a surface of walls with different constructions were determined by detectors CR-39. The values of the exhalation rate of radon per unit area of the granite, concrete, fired and unfired bricks, sand, cement, alabaster varied 0.091 - 0.1 Bq·m -2 ·h -1 . The surface of walls of dwellings constructed from different building materials the exhalation rate of radon are within in limits of 0.083-1.12 Bq·m -2 ·h -1 . Were measurements with CR-39 detectors a level of radon within 50-520 Bq/m 3 in air of rooms constructed of the different building materials

Dynamics of one-dimensional domain walls interacting with disorder potential

International Nuclear Information System (INIS)

Krusin-Elbaum, L.; Shibauchi, T.; Argyle, B.; Gignac, L.; Zabel, T.; Weller, D.

2001-01-01

Dynamics of 1D perpendicular-anisotropy domain walls in a few monolayer-thin Co films is imaged by polar Kerr microscopy. When domain walls, driven by a square-pulsed magnetic fields, travel through a random disordered potential landscape, they display Gaussian-distributed roughness characteristic of this landscape. Average velocity of the domain wall driven by a constant magnetic field strongly depends on a strain field which modifies (increases) the elastic energy of the wall and reduces the wall velocity

Numerical analysis of a PCM thermal storage system with varying wall temperature

International Nuclear Information System (INIS)

Halawa, E.; Bruno, F.; Saman, W.

2005-01-01

Numerical analysis of melting and freezing of a PCM thermal storage unit (TSU) with varying wall temperature is presented. The TSU under analysis consists of several layers of thin slabs of a PCM subjected to convective boundary conditions where air flows between the slabs. The model employed takes into account the variations in wall temperature along the direction of air flow as well as the sensible heat. The paper discusses typical characteristics of the melting/freezing of PCM slabs in an air stream and presents some results of the numerical simulation in terms of air outlet temperatures and heat transfer rates during the whole periods of melting and freezing. Considerations in the design of the TSU are also given

One-loop fluctuation-dissipation formula for bubble-wall velocity

International Nuclear Information System (INIS)

Arnold, P.

1993-01-01

The limiting bubble-wall velocity during a first-order electroweak phase transition is of interest in scenarios for electroweak baryogenesis. Khlebnikov has recently proposed an interesting method for computing this velocity based on the fluctuation-dissipation theorem. I demonstrate that at one-loop order this method is identical to simple, earlier techniques for computing the wall velocity based on computing the friction from particles reflecting off or transmitting through the wall in the ideal gas (''thin-wall'') limit

Failure analysis of the boiler water-wall tube

OpenAIRE

S.W. Liu; W.Z. Wang; C.J. Liu

2017-01-01

Failure analysis of the boiler water-wall tube is presented in this work. In order to examine the causes of failure, various techniques including visual inspection, chemical analysis, optical microscopy, scanning electron microscopy and energy dispersive spectroscopy were carried out. Tube wall thickness measurements were performed on the ruptured tube. The fire-facing side of the tube was observed to have experienced significant wall thinning. The composition of the matrix material of the tu...

Continuously renewed wall for a thermonuclear reactor

International Nuclear Information System (INIS)

Livshits, A.I.; Pustovojt, YU.M.; Samartsev, A.A.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Atomnoj Ehnergii)

1982-01-01

The possibility of creating a continuously renewed first wall of a thermonuclear reactor is experimentally investigated. The following variants of the wall are considered: the wall is double, its part turned to plasma is made of comparatively thin material. The external part separated from it by a small gap appears to be protected from interaction with plasma and performs structural functions. The gap contains the mixture of light helium and hydrogen and carbon-containing gas. The light gas transfers heat from internal part of the wall to the external part. Carbon-containing gas provides continuous renewal of carbon coating of the operating surface. The experiment is performed with palladium membrane 20 μm thick. Carbon is introduced into the membrane by benzol pyrolysis on one of the surfaces at the membrane temperature of 900 K. Carbon removal from the operating side of the wall due to its spraying by fast particles is modelled by chemical itching with oxygen given to the operating membrane wall. Observation of the carbon release on the operating surface is performed mass-spectrometrically according to the observation over O 2 transformation into CO and CO 2 . It is shown that in cases of benzol pressure of 5x10 -7 torr, carbon current on the opposite surface is not less than 3x10 12 atoms/sm 2 s and corresponds to the expected wall spraying rate in CF thermonuclear reactors. It is also shown that under definite conditions the formation and maintaining of a through protective carbon coating in the form of a monolayer or volumetric phase is possible

Upper and Lower Bound Limit Loads for Thin-Walled Pressure Vessels Used for Aerosol Cans

Directory of Open Access Journals (Sweden)

Stephen John Hardy

2009-01-01

Full Text Available The elastic compensation method proposed by Mackenzie and Boyle is used to estimate the upper and lower bound limit (collapse loads for one-piece aluminium aerosol cans, which are thin-walled pressure vessels subjected to internal pressure loading. Elastic-plastic finite element predictions for yield and collapse pressures are found using axisymmetric models. However, it is shown that predictions for the elastic-plastic buckling of the vessel base require the use of a full three-dimensional model with a small unsymmetrical imperfection introduced. The finite element predictions for the internal pressure to cause complete failure via collapse fall within the upper and lower bounds. Hence the method, which involves only elastic analyses, can be used in place of complex elastic-plastic finite element analyses when upper and lower bound estimates are adequate for design purposes. Similarly, the lower bound value underpredicts the pressure at which first yield occurs.

'Thin walled' concept and a new top lid applied to the Scandinavian PCRV for a boiling water reactor

International Nuclear Information System (INIS)

Scotto, F.L.

1975-01-01

This research is carried out in the frame of an agreement between AB ATOMENERGI of Sweden and ENEL (Ente Nazionale per l'Energia Elettrica) of Italy, for an exchange of information in the field of PCPV for BWR, and takes as a reference the Scandinavian solution as far as the thermal insulation system and the geometry are concerned, proposing new solutions for the prestressed concrete structure (namely the Author's concept of thin walls and a new concept of top lid). The proposed top lid sealing system solution is in line with the one adopted for the conventional steel pressure vessel enclosures; furthermore the prestressed concrete lid is restricted to the prestressed concrete structure to form a continuous contrete structure, in line with th PCPV conventional solutions for gas reactors. The paper describes in detail the selected design philosophy that is slightly different from the one defined by the Scandinavian project. In fact, as far as the design limits are concerned, it refers mainly to steel pressure vessel philosophy and, as to the concrete behaviour, to the design philosophy proposed by the author for the PCPV 'thin walled' structures for gas-cooled power reactors. Rheological, mathematical and physical models had been suitably devised in order to check the reliability of the proposed assumption. This paper therefore, will also give a brief description of said tools and the main results acquired at the time of the conference, and technical and economical considerations made to support the interest of the research, showing the relevant cut down of the costs. The comparative reference steel pressure vessel belongs to Mark III ENEL VI and VIII BW plant to which design and construction the author gives his contribution

Physical properties of SnS thin films grown by hot wall deposition

International Nuclear Information System (INIS)

Gremenok, V.; Ivanov, V.; Bashkirov, S.; Unuchak, D.; Lazenka, V.; Bente, K.; Tashlykov, I.; Turovets, A.

2010-01-01

Full text : Recently, considerable effort has been invested to gain a better and deeper knowledge of structural and physical properties of metal chalcogenide semiconductors because of their potential application in electrical and photonic devices. Among them, tin sulphide (SnS) has attracted attention because of band gap of 1.3 eV and an absorption coefficient greater than 10 4 cm - 1. Additionally, by using tin sulfide compounds for photovoltaic devices, the production costs are decreased, because these materials are cheap and abundant in nature. For the sythesis of SnS thin films by hot wall deposition, SnS ingots were used as the source materials synthesized from high purity elements (99.999 percent). The thin films were grown onto glass at substrate temperatures between 220 and 380 degrees Celsium. The thickness of the films was in the range of 1.0 - 2.5 μm. The crystal structure and crystalline phases of the materials were studied by XRD using a Siemens D-5000 diffractometer with CuK α (λ = 1.5418 A) radiation. In order to consider instrumental error, the samples were coated by Si powder suspended in acetone. The composition and surface morphology of thin films were investigated by electron probe microanalysis (EPMA) using a CAMECA SX-100, a scanning electron microscope JEOL 6400 and an atomic force microscope (AFM, Model: NT 206), respectively. Depth profiling was performed by Auger electron spectroscopy (AES) using a Perkin Elmer Physical Electronics 590. The electrical resistivity was studied by van der Pauw four-probe technique using silver paste contact. The optical transmittance was carried out using a Varian Cary 50 UV - VIS spectrophotometer in the range 500 - 2000 nm. The as-grown films exhibited a composition with a Sn/S at. percent ratio of 1.06. The AES depth profiles revealed relatively uniform composition through the film thickness. The XRD analysis of the SnS films showed that they were monophase (JCPDS 39-0354), polycrystalline with

Evolution of titanium residue on the walls of a plasma-etching reactor and its effect on the polysilicon etching rate

Energy Technology Data Exchange (ETDEWEB)

Hirota, Kosa, E-mail: hirota-kousa@sme.hitachi-hitec.com; Itabashi, Naoshi; Tanaka, Junichi [Hitachi, Ltd., Central Research Laboratory, 1-280, Higashi-Koigakubo, Kokubunji, Tokyo 185-8601 (Japan)

2014-11-01

The variation in polysilicon plasma etching rates caused by Ti residue on the reactor walls was investigated. The amount of Ti residue was measured using attenuated total reflection Fourier transform infrared spectroscopy with the HgCdTe (MCT) detector installed on the side of the reactor. As the amount of Ti residue increased, the number of fluorine radicals and the polysilicon etching rate increased. However, a maximum limit in the etching rate was observed. A mechanism of rate variation was proposed, whereby F radical consumption on the quartz reactor wall is suppressed by the Ti residue. The authors also investigated a plasma-cleaning method for the removal of Ti residue without using a BCl{sub 3} gas, because the reaction products (e.g., boron oxide) on the reactor walls frequently cause contamination of the product wafers during etching. CH-assisted chlorine cleaning, which is a combination of CHF{sub 3} and Cl{sub 2} plasma treatment, was found to effectively remove Ti residue from the reactor walls. This result shows that CH radicals play an important role in deoxidizing and/or defluorinating Ti residue on the reactor walls.

Study of air and steam leak rate through damaged concrete wall

International Nuclear Information System (INIS)

Abdeslam Laghcha; Gerard Debicki; Benoit Masson

2005-01-01

Full text of publication follows: The leak rate prediction of air and steam through a cracked concrete wall is an extremely important issue in assessing the safety of nuclear reactor containment building. Furthermore the relation between air leak rate and steam leak rate on the same wall could have some interest for safety prediction. This laboratory study investigates the transfer of fluids through a wall of 1.3 m of thickness, with a focus on two cases: one on a mechanically damaged concrete by compressive stress and another one on a crossing artificial flaw in a construction joint realized in the concrete specimen (cylindrical / section 0.1925 m 2 / length 1.3 m). The both specimens were made of ordinary concrete (compressive strength: 35 MPa). To initiate residual compressive cracks, the specimen (A) was loaded in compression under controlled strains until a level of 90% of the failure strain was reached. To create a crossing artificial flaw in a construction joint, the concrete was set in the mould in two times, the second time, a water saturated sand bed was placed on the surface of the hardened concrete to realize the flaw along a diameter of the specimen (B). The permeability of damaged concrete wall was studied comparatively under two conditions, but without appreciable stresses applied on. The first condition was at ambient temperature, a reference test of permeability, with dry air, gave the characteristics of permeability and the type of flow through the specimen. In this case, the used method consisted to proceed by stages. The imposed pressures on the exposed face were successively 0.1, 0.18, 0.23, 0.28, 0.34 and 0.42 MPa, the other face was at atmospheric pressure. The second condition was an accidental scenario with simultaneous effects of temperature and gas (a mix of air and steam) pressure applied on a face, the other one remaining at atmospheric pressure and temperature. During the test, the lateral face of the cylindrical specimen was thermally

Operational Windows for Dry-Wall and Wetted-Wall IFE Chambers

International Nuclear Information System (INIS)

Najmabadi, F.; Raffray, A.R.; Bromberg, L.

2004-01-01

The ARIES-IFE study was an integrated study of inertial fusion energy (IFE) chambers and chamber interfaces with the driver and target systems. Detailed analysis of various subsystems was performed parametrically to uncover key physics/technology uncertainties and to identify constraints imposed by each subsystem. In this paper, these constraints (e.g., target injection and tracking, thermal response of the first wall, and driver propagation and focusing) were combined to understand the trade-offs, to develop operational windows for chamber concepts, and to identify high-leverage research and development directions for IFE research. Some conclusions drawn in this paper are (a) the detailed characterization of the target yield and spectrum has a major impact on the chamber; (b) it is prudent to use a thin armor instead of a monolithic first wall for dry-wall concepts; (c) for dry-wall concepts with direct-drive targets, the most stringent constraint is imposed by target survival during the injection process; (d) for relatively low yield targets (<250 MJ), an operational window with no buffer gas may exist; (e) for dry-wall concepts with indirect-drive targets, a high buffer gas pressure would be necessary that may preclude propagation of the laser driver and require assisted pinch transport for the heavy-ion driver; and (f) generation and transport of aerosols in the chamber is the key feasibility issue for wetted-wall concepts

Pulse wave velocity as a diagnostic index: The effect of wall thickness

Science.gov (United States)

Hodis, Simona

2018-06-01

Vascular compliance is a major determinant of wave propagation within the vascular system, and hence the measurement of pulse wave velocity (PWV) is commonly used clinically as a method of detecting vascular stiffening. The accuracy of that assessment is important because vascular stiffening is a major risk factor for hypertension. PWV is usually measured by timing a pressure wave as it travels from the carotid artery to the femoral or radial artery and estimating the distance that it traveled in each case to obtain the required velocity. A major assumption on which this technique is based is that the vessel wall thickness h is negligibly small compared with the vessel radius a . The extent to which this assumption is satisfied in the cardiovascular system is not known because the ratio h /a varies widely across different regions of the vascular tree and under different pathological conditions. Using the PWV as a diagnostic test without knowing the effect of wall thickness on the measurement could lead to error when interpreting the PWV value as an index of vessel wall compliance. The aim of the present study was to extend the validity of the current practice of assessing wall stiffness by developing a method of analysis that goes beyond the assumption of a thin wall. We analyzed PWVs calculated with different wall models, depending on the ratio of wall thickness to vessel radius and the results showed that PWV is not reliable when it is estimated with the classic thin wall theory if the vessel wall is not around 25% of vessel radius. If the arterial wall is thicker than 25% of vessel radius, then the wave velocity calculated with the thin wall theory could be overestimated and in the clinical setting, this could lead to a false positive. For thicker walls, a thick wall model presented here should be considered to account for the stresses within the wall thickness that become dominant compared with the wall inertia.

Fabrication of PDMS/SWCNT thin films as saturable absorbers

International Nuclear Information System (INIS)

Hernandez-Romano, I; Sanchez-Mondragon, J J; Davila-Rodriguez, J; Delfyett, P J; May-Arrioja, D A

2011-01-01

We present a novel technique to fabricate a saturable absorber thin film based on Polydimethylsiloxane doped with Single Wall Carbon Nanotubes. Using this film a passive mode-locked fiber laser in a standard ring cavity configuration was built by inserting the film between two angled connectors. Self-starting passively mode-locked laser operation was easily observed. The generated pulses have a width of 1.26 ps at a repetition rate of 22.7 MHz with an average power of 4.89 mW.

Domain reversal dynamics in ferromagnetic thin films of Co/Pd nanomultilayers

International Nuclear Information System (INIS)

Choe, Sug Bong; Kim, Dong Hyun; Shin, Sung Chul

2002-01-01

Domain reversal dynamics in ferromagnetic thin films has been quantitatively investigated by means of a magneto-optical microscope magnetometer (MOMM), capable of grabbing domain reversal patterns in real time under an applied magnetic field and of measuring local magnetic properties with 400-nm spatial resolution. The domain reversal behavior sensitively changed between wall-motion and nucleation-dominant behavior with changing multilayer structure of the Co-Pd multilayers. Quantitative analysis revealed that the contrasting reversal behavior was mainly caused by a sensitive change in wall-motion speed and that the reversal ratio of wall-motion speed over nucleation rate was a governing parameter for the contrasting domain reversal dynamics. The activation volumes of the wall-motion and nucleation processes were generally unequal, and the inequality was closely related with the domain dynamics. Based on a Monte-Carlo simulation, both the macroscopic magnetic properties and the local magnetic variation were responsible for the contrasting domain reversal behavior

Mechanobiology of LDL mass transport in the arterial wall under the effect of magnetic field, part I: Diffusion rate

Energy Technology Data Exchange (ETDEWEB)

Aminfar, Habib, E-mail: hh_aminfar@tabrizu.ac.ir [Faculty of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of); Mohammadpourfard, Mousa, E-mail: Mohammadpour@tabrizu.ac.ir [Faculty of Chemical and Petroleum Engineering, University of Tabriz, Tabriz 5166616471 (Iran, Islamic Republic of); Khajeh, Kosar, E-mail: k.khajeh.2005@tabrizu.ac.ir [Faculty of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2017-03-15

It is well-known that the Low Density Lipoprotein (LDL) can accumulate and penetrate into the arterial wall. Here, we have investigated the diffusion rate of macromolecules across the porous layer of blood vessel under the effects of magnetic force. By using a finite volume technique, it was found that magnetic field makes alterations in diffusion rate of LDLs, also surface concentration of macromolecules on the walls. As well, the influence of different value of Re and Sc number in the presence of a magnetic field have shown as nondimensional concentration profiles. Magnetic field considered as a body force, porous layer simulated by using Darcy's law and the blood regarded as nano fluid which was examined as a single phase model. - Highlights: • LDLs mass transfer across the arterial wall under magnetic field has simulated numerically. • Arterial wall assumed as a homogeneous porous layer by using Darcy's law. • Blood containing 4% Vol. Fe{sub 3}O{sub 4} regarded as nanofluid and has examined by single phase model. • Magnetic field significantly affects the diffusion rate of LDLs through porous arterial wall.

Shear thinning and shear thickening of a confined suspension of vesicles

Science.gov (United States)

Nait Ouhra, A.; Farutin, A.; Aouane, O.; Ez-Zahraouy, H.; Benyoussef, A.; Misbah, C.

2018-01-01

Widely regarded as an interesting model system for studying flow properties of blood, vesicles are closed membranes of phospholipids that mimic the cytoplasmic membranes of red blood cells. In this study we analyze the rheology of a suspension of vesicles in a confined geometry: the suspension, bound by two planar rigid walls on each side, is subject to a shear flow. Flow properties are then analyzed as a function of shear rate γ ˙, the concentration of the suspension ϕ , and the viscosity contrast λ =ηin/ηout , where ηin and ηout are the fluid viscosities of the inner and outer fluids, respectively. We find that the apparent (or effective viscosity) of the suspension exhibits both shear thinning (decreasing viscosity with shear rate) or shear thickening (increasing viscosity with shear rate) in the same concentration range. The shear thinning or thickening behaviors appear as subtle phenomena, dependant on viscosity contrast λ . We provide physical arguments on the origins of these behaviors.

Appropriate materials and preparation techniques for polycrystalline-thin-film thermophotovoltaic cells

Science.gov (United States)

Dhere, Neelkanth G.

1997-03-01

Polycrystalline-thin-film thermophotovoltaic (TPV) cells have excellent potential for reducing the cost of TPV generators so as to address the hitherto inaccessible and highly competitive markets such as self-powered gas-fired residential warm air furnaces and energy-efficient electric cars, etc. Recent progress in polycrystalline-thin-film solar cells have made it possible to satisfy the diffusion length and intrinsic junction rectification criteria for TPV cells operating at high fluences. Continuous ranges of direct bandgaps of the ternary and pseudoternary compounds such as Hg1-xCdxTe, Pb1-xCdxTe, Hg1-xZnxTe, and Pb1-xZnxS cover the region of interest of 0.50-0.75 eV for efficient TPV conversion. Other ternary and pseudoternary compounds which show direct bandgaps in most of or all of the 0.50-0.75 eV range are Pb1-xZnxTe, Sn1-xCd2xTe2, Pb1-xCdxSe, Pb1-xZnxSe, and Pb1-xCdxS. Hg1-xCdxTe (with x~0.21) has been studied extensively for infrared detectors. PbTe and Pb1-xSnxTe have also been studied for infrared detectors. Not much work has been carried out on Hg1-xZnxTe thin films. Hg1-xCdxTe and Pb1-xCdxTe alloys cover a wide range of cut-off wavelengths from the far infrared to the near visible. Acceptors and donors are introduced in these materials by excess non-metal (Te) and excess metal (Hg and Pb) respectively. Extrinsic acceptor impurities are Cu, Au, and As while and In and Al are donor impurities. Hg1-xCdxTe thin films have been deposited by isothermal vapor-phase epitaxy (VPE), liquid phase epitaxy (LPE), hot-wall metalorganic chemical vapor deposition (MOCVD), electrodeposition, sputtering, molecular beam epitaxy (MBE), laser-assisted evaporation, and vacuum evaporation with or without hot-wall enclosure. The challenge in the preparation of Hg1-xCdxTe is to provide excess mercury incidence rate, to optimize the deposition parameters for enhanced mercury incorporation, and to achieve the requisite stoichiometry, grain size, and doping. MBE and MOCVD

Effect of inactive yeast cell wall on growth performance, survival rate and immune parameters in Pacific White Shrimp (Litopenaeus vannamei

Directory of Open Access Journals (Sweden)

Rutchanee Chotikachinda

2008-10-01

Full Text Available Effects of dietary inactive yeast cell wall on growth performance, survival rate, and immune parameters in pacific white shrimp (Litopenaeus vannamei was investigated. Three dosages of inactive yeast cell wall (0, 1, and 2 g kg-1 were tested in three replicate groups of juvenile shrimps with an average initial weight of 7.15±0.05 g for four weeks. There was no significant difference in final weight, survival rate, specific growth rate, feed conversion ratio, feed intake, protein efficiency ratio, and apparent net protein utilization of each treatments. However, different levels of inactive yeast cell wall showed an effect on certain immune parameters (p<0.05. Total hemocyte counts, granular hemocyte count, and bacterial clearance were better in shrimp fed diets supplemented with 1 and 2 g kg-1 inactive yeast cell wall as compared with thecontrol group.

Nonlinear optical properties of polyaniline and poly (o-toluidine) composite thin films with multi walled carbon nano tubes

Energy Technology Data Exchange (ETDEWEB)

Nagaraja, K.K. [National University of Science and Technology “MISiS”, Leninskii pr. 4, Moscow 119049 (Russian Federation); Pramodini, S. [Department of Physics, School of Engineering and Technology, Jain University, Jakkasandra Post, Bengaluru 5621112, Karnataka (India); Poornesh, P., E-mail: poorneshp@gmail.com [Nonlinear Optics Research Laboratory, Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576 104, Karnataka (India); Telenkov, M.P. [National University of Science and Technology “MISiS”, Leninskii pr. 4, Moscow 119049 (Russian Federation); Kityk, I.V. [Electrical Engineering Department, Czestochowa University Technology, Czestochowa (Poland)

2017-05-01

We report the improved third-order nonlinear optical properties of polyaniline and poly (o-toluidine) with different doping concentrations of multi walled carbon nano tube (MWCNTs) composite thin films investigated using z-scan technique and continuous wave He–Ne laser at 633 nm wavelength was used as source of excitation. Thin films were prepared by spin coating technique on glass substrate. The structural properties of the composite films were analysed by X-ray diffraction studies and the characteristic peaks corresponding to MWCNTs and polymers have been observed. The surface morphology of the deposited films was analysed using scanning electron microscopy and it confirms that the polymer in the composites has been coated on the MWCNTs homogeneously. The z-scan results reveal that the films exhibit reverse saturable absorption and self-defocusing nonlinearity. The third-order nonlinear optical susceptibility χ{sup (3)} is found to be of the order of 10{sup −3} esu. Also, optical power limiting and clamping experiment was performed. The clamping values increases with increase in concentration and the lowest clamping observed for composite films are 1 mW and 0.7 mW.

Standardized procedure for eddy-current testing of stainless steel, thin-walled nuclear fuel element cladding tubes

Energy Technology Data Exchange (ETDEWEB)

Barat, P; Raj, B; Bhattacharya, D K [Reactor Research Centre, Kalpakkam (India)

1982-10-01

Thin-walled nuclear fuel cladding tubes made of AISI 316 stainless steel have been examined by eddy-current testing. Standardization of the procedures has required investigations on optimizing the test frequency, finding a method to locate a defect with respect to the probe reference end, and the use of standard defects and sequential metallography of natural defects detected by eddy-current testing, to understand the influence of the nature of defects on the impedance output signals. Test frequency and method of locating the defect were optimized by the use of standard defects made by machining in reference cladding tubes. Subsequent metallography of natural defects detected by eddy-current testing revealed mainly clusters of inclusions but also other types of defects. The effect of the distribution of inclusions along the length of the tube on the impedance output is discussed.

Development of Integrated Die Casting Process for Large Thin-Wall Magnesium Applications

Energy Technology Data Exchange (ETDEWEB)

Carter, Jon T. [General Motors LLC, Warren, MI (United States); Wang, Gerry [Meridian Lightweight Technologies, Plymouth MI (United States); Luo, Alan [General Motors LLC, Warren, MI (United States)

2017-11-29

The purpose of this project was to develop a process and product which would utilize magnesium die casting and result in energy savings when compared to the baseline steel product. The specific product chosen was a side door inner panel for a mid-size car. The scope of the project included: re-design of major structural parts of the door, design and build of the tooling required to make the parts, making of parts, assembly of doors, and testing (both physical and simulation) of doors. Additional work was done on alloy development, vacuum die casting, and overcasting, all in order to improve the performance of the doors and reduce cost. The project achieved the following objectives: 1. Demonstrated ability to design a large thin-wall magnesium die casting. 2. Demonstrated ability to manufacture a large thin-wall magnesium die casting in AM60 alloy. 3. Tested via simulations and/or physical tests the mechanical behavior and corrosion behavior of magnesium die castings and/or lightweight experimental automotive side doors which incorporate a large, thin-wall, powder coated, magnesium die casting. Under some load cases, the results revealed cracking of the casting, which can be addressed with re-design and better material models for CAE analysis. No corrosion of the magnesium panel was observed. 4. Using life cycle analysis models, compared the energy consumption and global warming potential of the lightweight door with those of a conventional steel door, both during manufacture and in service. Compared to a steel door, the lightweight door requires more energy to manufacture but less energy during operation (i.e., fuel consumption when driving vehicle). Similarly, compared to a steel door, the lightweight door has higher global warming potential (GWP) during manufacture, but lower GWP during operation. 5. Compared the conventional magnesium die casting process with the “super-vacuum” die casting process. Results achieved with cast tensile bars suggest some

State of the art in thin film thickness and deposition rate monitoring sensors

International Nuclear Information System (INIS)

Buzea, Cristina; Robbie, Kevin

2005-01-01

In situ monitoring parameters are indispensable for thin film fabrication. Among them, thickness and deposition rate control are often the most important in achieving the reproducibility necessary for technological exploitation of physical phenomena dependent on film microstructure. This review describes the types of thickness and deposition rate sensors and their theoretical and phenomenological background, underlining their performances, as well as advantages and disadvantages

Domain wall engineering through exchange bias

International Nuclear Information System (INIS)

Albisetti, E.; Petti, D.

2016-01-01

The control of the structure and position of magnetic domain walls is at the basis of the development of different magnetic devices and architectures. Several nanofabrication techniques have been proposed to geometrically confine and shape domain wall structures; however, a fine tuning of the position and micromagnetic configuration is hardly achieved, especially in continuous films. This work shows that, by controlling the unidirectional anisotropy of a continuous ferromagnetic film through exchange bias, domain walls whose spin arrangement is generally not favored by dipolar and exchange interactions can be created. Micromagnetic simulations reveal that the domain wall width, position and profile can be tuned by establishing an abrupt change in the direction and magnitude of the exchange bias field set in the system. - Highlights: • Micromagnetic simulations study domain walls in exchange biased thin films. • Novel domain wall configurations can be stabilized via exchange bias. • Domain walls nucleate at the boundary of regions with different exchange bias. • Domain wall width and spin profile are controlled by tuning the exchange bias.

Conceptual design of the INTOR first-wall system

International Nuclear Information System (INIS)

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

Thin low Z coatings for plasma devices

International Nuclear Information System (INIS)

Norem, J.; Bowers, D.A.

1978-05-01

Coating the walls of the vacuum chamber with beryllium or some other low Z material has been proposed as a possible means of solving the problems of high Z influx into plasmas. We attempt to demonstrate that very thin, low Z coatings are compatible with the operation of plasma devices and beneficial to plasma performance. We determine that the thickness of coating material required is only about 10 monolayers. In a radiation environment, radiation-induced solute segregation should help to maintain the integrity of such thin coatings against diffusion and other processes. We discuss the properties of these thin coatings and possible means of in situ application and maintenance. Since deposition of plasma impurities on the walls will occur anyway, we discuss injection of solid pellets into the plasma as a direct way of introducing impurities which would ultimately serve as coating material

Finite element limit loads for non-idealized through-wall cracks in thick-walled pipe

International Nuclear Information System (INIS)

Shim, Do-Jun; Han, Tae-Song; Huh, Nam-Su

2013-01-01

Highlights: • The lower bound bulging factor of thin-walled pipe can be used for thick-walled pipe. • The limit loads are proposed for thick-walled, transition through-wall cracked pipe. • The correction factors are proposed for estimating limit loads of transition cracks. • The limit loads of short transition cracks are similar to those of idealized cracks. - Abstract: The present paper provides plastic limit loads for non-idealized through-wall cracks in thick-walled pipe. These solutions are based on detailed 3-dimensional finite element (FE) analyses which can be used for structural integrity assessment of nuclear piping. To cover a practical range of interest, the geometric variables and loading conditions affecting the plastic limit loads of thick-walled pipe with non-idealized through-wall cracks were systematically varied. In terms of crack orientation, both circumferential and axial through-wall cracks were considered. As for loading conditions, axial tension, global bending, and internal pressure were considered for circumferential cracks, whereas only internal pressure was considered for axial cracks. Furthermore, the values of geometric factor representing shape characteristics of non-idealized through-wall cracks were also systematically varied. In order to provide confidence in the present FE analyses results, plastic limit loads of un-cracked, thick-walled pipe resulting from the present FE analyses were compared with the theoretical solutions. Finally, correction factors to the idealized through-wall crack solutions were developed to determine the plastic limit loads of non-idealized through-wall cracks in thick-walled pipe

Domain switching of fatigued ferroelectric thin films

Science.gov (United States)

Tak Lim, Yun; Yeog Son, Jong; Shin, Young-Han

2014-05-01

We investigate the domain wall speed of a ferroelectric PbZr0.48Ti0.52O3 (PZT) thin film using an atomic force microscope incorporated with a mercury-probe system to control the degree of electrical fatigue. The depolarization field in the PZT thin film decreases with increasing the degree of electrical fatigue. We find that the wide-range activation field previously reported in ferroelectric domains result from the change of the depolarization field caused by the electrical fatigue. Domain wall speed exhibits universal behavior to the effective electric field (defined by an applied electric field minus the depolarization field), regardless of the degree of the electrical fatigue.

Domain switching of fatigued ferroelectric thin films

International Nuclear Information System (INIS)

Tak Lim, Yun; Yeog Son, Jong; Shin, Young-Han

2014-01-01

We investigate the domain wall speed of a ferroelectric PbZr 0.48 Ti 0.52 O 3 (PZT) thin film using an atomic force microscope incorporated with a mercury-probe system to control the degree of electrical fatigue. The depolarization field in the PZT thin film decreases with increasing the degree of electrical fatigue. We find that the wide-range activation field previously reported in ferroelectric domains result from the change of the depolarization field caused by the electrical fatigue. Domain wall speed exhibits universal behavior to the effective electric field (defined by an applied electric field minus the depolarization field), regardless of the degree of the electrical fatigue

Theoretical Analysis of Effects of Wall Suction on Entropy Generation Rate in Laminar Condensate Layer on Horizontal Tube

Directory of Open Access Journals (Sweden)

Tong-Bou Chang

2014-01-01

Full Text Available The effects of wall suction on the entropy generation rate in a two-dimensional steady film condensation flow on a horizontal tube are investigated theoretically. In analyzing the liquid flow, the effects of both the gravitational force and the viscous force are taken into account. In addition, a film thickness reduction ratio, Sf, is introduced to evaluate the effect of wall suction on the thickness of the condensate layer. The analytical results show that, the entropy generation rate depends on the Jakob number Ja, the Rayleigh number Ra, the Brinkman number Br, the dimensionless temperature difference ψ, and the wall suction parameter Sw. In addition, it is shown that in the absence of wall suction, a closed-form correlation for the Nusselt number can be derived. Finally, it is shown that the dimensionless entropy generation due to heat transfer, NT, increases with an increasing suction parameter Sw, whereas the dimensionless entropy generation due to liquid film flow friction, NF, decreases.

The Effect of Deposition Rate on Electrical, Optical and Structural Properties of ITO Thin Films

Directory of Open Access Journals (Sweden)

P. S. Raghupathi

2005-01-01

Full Text Available Indium tin oxide (ITO thin films have been prepared using the reactive evaporation technique on glass substrates in an oxygen atmosphere. It is found that the deposition rate plays prominent role in controlling the electrical and optical properties of the ITO thin films. Resistivity, electrical conductivity, activation energy, optical transmission and band gap energy were investigated. A transmittance value of more than 90% in the visible region of the spectrum and an electrical conductivity of 3x10–6 Ωm has been obtained with a deposition rate of 2 nm/min. XRD studies showed that the films are polycrystalline.

Low mass MEMS/NEMS switch for a substitute of CMOS transistor using single-walled carbon nanotube thin film

Science.gov (United States)

Jang, Min-Woo

Power dissipation is a key factor for mobile devices and other low power applications. Complementary metal oxide semiconductor (CMOS) is the dominant integrated circuit (IC) technology responsible for a large part of this power dissipation. As the minimum feature size of CMOS devices enters into the sub 50 nanometer (nm) regime, power dissipation becomes much worse due to intrinsic physical limits. Many approaches have been studied to reduce power dissipation of deeply scaled CMOS ICs. One possible candidate is the electrostatic electromechanical switch, which could be fabricated with conventional CMOS processing techniques. They have critical advantages compared to CMOS devices such as almost zero standby leakage in the off-state due to the absence of a pn junction and a gate oxide, as well as excellent drive current in the on-state due to a metallic channel. Despite their excellent standby power dissipation, the electrostatic MEMS/NEMS switches have not been considered as a viable replacement for CMOS devices due to their large mechanical delay. Moreover, previous literature reveals that their pull-in voltage and switching speed are strongly proportional to each other. This reduces their potential advantage. However, in this work, we theoretically and experimentally demonstrated that the use of single-walled carbon nanotube (SWNT) with very low mass density and strong mechanical properties could provide a route to move off of the conventional trend with respect to the pull-in voltage / switching speed tradeoff observed in the literature. We fabricated 2-terminal fixed- beam switches with aligned composite SWNT thin films. In this work, layer-by-layer (LbL) self-assembly and dielectrophoresis were selected for aligned-composite SWNT thin film deposition. The dense membranes were successfully patterned to form submicron beams by e-beam lithography and oxygen plasma etching. Fixed-fixed beam switches using these membranes successfully operated with approximately 600

Structural design of shield-integrated thin-wall vacuum vessel and manufacturing qualification tests for International Thermonuclear Experimental Reactor (ITER)

International Nuclear Information System (INIS)

Shimizu, Katsusuke; Shibui, Masanao; Koizumi, Koichi; Kanamori, Naokazu; Nishio, Satoshi; Sasaki, Takashi; Tada, Eisuke

1992-09-01

Conceptual design of shield-integrated thin-wall vacuum vessel has been done for ITER (International Thermonuclear Experimental Reactor). The vacuum vessel concept is based on a thin-double-wall structure, which consists of inner and outer plates and rib stiffeners. Internal shielding structures, which provide neutron irradiation shielding to protect TF coils, are set up between the inner plate and the outer plate of the vessel to avoid complexity of machine systems such as supporting systems of blanket modules. The vacuum vessel is assembled/disassembled by remote handling, so that welding joints are chosen as on-site joint method from reliability of mechanical strength. From a view point of assembling TF coils, the vacuum vessel is separated at the side of port, and is divided into 32 segments similar to the ITER-CDA reference design. Separatrix sweeping coils are located in the vacuum vessel to reduce heat fluxes onto divertor plates. Here, the coil structure and attachment to the vacuum vessel have been investigated. A sectorized saddle-loop coil is available for assembling and disassembling the coil. To support electromagnetic loads on the coils, they are attached to the groove in the vacuum vessel by welding. Flexible multi-plate supporting structure (compression-type gravity support), which was designed during CDA, is optimized by investigating buckling and frequency response properties, and concept on manufacturing and fabrication of the gravity support are proposed. Partial model of the vacuum vessel is manufactured for trial, so that fundamental data on welding and fabrication are obtained. From mechanical property tests of weldment and partial models, mechanical intensity and behaviors of the weldment are obtained. Informations on FEM-modeling are obtained by comparing analysis results with experimental results. (author)

Thick domain wall spacetimes with and without reflection symmetry

International Nuclear Information System (INIS)

Melfo, Alejandra; Pantoja, Nelson; Skirzewski, Aureliano

2003-01-01

We show that different thick domain wall spacetimes, for which the scalar field configuration and the potential are the same, can be found as solutions to the coupled Einstein-scalar field equations, depending on whether or not reflection symmetry on the wall is imposed. Spacetimes with reflection symmetry may be dynamic or static, while the asymmetric ones are static. Asymmetric walls are asymptotically flat on one side and reduce to the Taub spacetime on the other. Examples of asymmetric thick walls in D-dimensional spacetimes are given, and previous analysis on the distributional thin-wall limit of the dynamic symmetric thick walls are extended to the asymmetric case. A new family of reflection symmetric, static thick domain wall spacetimes, including previously known Bogomol'nyi-Prasad-Sommerfield walls, is presented

Tissue factor levels and the fibrinolytic system in thin and thick intraluminal thrombus and underlying walls of abdominal aortic aneurysms.

Science.gov (United States)

Siennicka, Aldona; Zuchowski, Marta; Kaczmarczyk, Mariusz; Cnotliwy, Miłosław; Clark, Jeremy Simon; Jastrzębska, Maria

2018-03-20

The hemostatic system cooperates with proteolytic degradation in processes allowing abdominal aortic aneurysm (AAA) formation. In previous studies, it has been suggested that aneurysm rupture depends on intraluminal thrombus (ILT) thickness, which varies across each individual aneurysm. We hypothesized that hemostatic components differentially accumulate in AAA tissue in relation to ILT thickness. Thick (A1) and thin (B1) segments of ILTs and aneurysm wall sections A (adjacent to A1) and B (adjacent to B1) from one aneurysm sac were taken from 35 patients undergoing elective repair. Factor levels were measured using enzyme-linked immunosorbent assay of protein extract. Tissue factor (TF) activities were significantly higher in thinner segments of AAA (B1 vs A1, P = .003; B vs A, P thick thrombus-covered wall segments (A) than in B, A1, and B1 (P = .015, P thick ILT (P = .021) and thick ILT (A1; P thick ILT (A1). However, no correlations were found at B sites, except for a correlation between plasmin and TF activities (r = 0.55; P = .004). These results suggest that higher TF activities are present in thinner AAA regions. These parameters and local fibrinolysis may be part of the processes leading to destruction of the aneurysm wall. Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Outgassing rates before, during and after bake-out for various vacuum and first wall candidate materials of a large tokamak device

International Nuclear Information System (INIS)

Yoshikawa, H.; Gomay, J.; Sugiyama, Y.; Mizuno, M.; Komiya, S.; Tazima, T.

1977-01-01

Outgassing rates of vacuum wall candidate materials; stainless steel SS-304L and YUS-170, Inconel-625 and Hastelloy-X, and first wall materials; molybdenum, pyrolytic graphite and silicon carbide are measured before, during and after a bake-out at 500 0 C. The outgassing rate from the inside wall of the cylinder made of each material is estimated from the pressure difference between before and after a calibrated orifice. The ultimate outgassing rates of SS-304L and pyrolytic graphite, and YUS-170 Inconel-625, Hastelloy-X and molybdenum are the orders of 10 -10 and 10 -11 Pa.l.s -1 cm -2 , respectively

Influence of cold walls on PET image quantification and volume segmentation: A phantom study

International Nuclear Information System (INIS)

Berthon, B.; Marshall, C.; Edwards, A.; Spezi, E.; Evans, M.

2013-01-01

Purpose: Commercially available fillable plastic inserts used in positron emission tomography phantoms usually have thick plastic walls, separating their content from the background activity. These “cold” walls can modify the intensity values of neighboring active regions due to the partial volume effect, resulting in errors in the estimation of standardized uptake values. Numerous papers suggest that this is an issue for phantom work simulating tumor tissue, quality control, and calibration work. This study aims to investigate the influence of the cold plastic wall thickness on the quantification of 18F-fluorodeoxyglucose on the image activity recovery and on the performance of advanced automatic segmentation algorithms for the delineation of active regions delimited by plastic walls.Methods: A commercial set of six spheres of different diameters was replicated using a manufacturing technique which achieves a reduction in plastic walls thickness of up to 90%, while keeping the same internal volume. Both sets of thin- and thick-wall inserts were imaged simultaneously in a custom phantom for six different tumor-to-background ratios. Intensity values were compared in terms of mean and maximum standardized uptake values (SUVs) in the spheres and mean SUV of the hottest 1 ml region (SUV max , SUV mean , and SUV peak ). The recovery coefficient (RC) was also derived for each sphere. The results were compared against the values predicted by a theoretical model of the PET-intensity profiles for the same tumor-to-background ratios (TBRs), sphere sizes, and wall thicknesses. In addition, ten automatic segmentation methods, written in house, were applied to both thin- and thick-wall inserts. The contours obtained were compared to computed tomography derived gold standard (“ground truth”), using five different accuracy metrics.Results: The authors' results showed that thin-wall inserts achieved significantly higher SUV mean , SUV max , and RC values (up to 25%, 16

Analysis of thin-walled cylindrical composite shell structures subject to axial and bending loads: Concept development, analytical modeling and experimental verification

Science.gov (United States)

Mahadev, Sthanu

Continued research and development efforts devoted in recent years have generated novel avenues towards the advancement of efficient and effective, slender laminated fiber-reinforced composite members. Numerous studies have focused on the modeling and response characterization of composite structures with particular relevance to thin-walled cylindrical composite shells. This class of shell configurations is being actively explored to fully determine their mechanical efficacy as primary aerospace structural members. The proposed research is targeted towards formulating a composite shell theory based prognosis methodology that entails an elaborate analysis and investigation of thin-walled cylindrical shell type laminated composite configurations that are highly desirable in increasing number of mechanical and aerospace applications. The prime motivation to adopt this theory arises from its superior ability to generate simple yet viable closed-form analytical solution procedure to numerous geometrically intense, inherent curvature possessing composite structures. This analytical evaluative routine offers to acquire a first-hand insight on the primary mechanical characteristics that essentially govern the behavior of slender composite shells under typical static loading conditions. Current work exposes the robustness of this mathematical framework via demonstrating its potential towards the prediction of structural properties such as axial stiffness and bending stiffness respectively. Longitudinal ply-stress computations are investigated upon deriving the global stiffness matrix model for composite cylindrical tubes with circular cross-sections. Additionally, this work employs a finite element based numerical technique to substantiate the analytical results reported for cylindrically shaped circular composite tubes. Furthermore, this concept development is extended to the study of thin-walled, open cross-sectioned, curved laminated shells that are geometrically

Stress in closed thin-walled tubes of single box subjected by shear forces and application to airfoils

Directory of Open Access Journals (Sweden)

Zebbiche Toufik

2014-09-01

Full Text Available The presented work is to develop a numerical computation program to determine the distribution of the shear stress to shear in closed tubes with asymmetric single thin wall section with a constant thickness and applications to airfoils and therefore determining the position and value of the maximum stress. In the literature, there are exact analytical solutions only for some sections of simple geometries such as circular section. Hence our interest is focused on the search of approximate numerical solutions for more complex sections used in aeronautics. In the second stage the position of the shear center is determined so that the section does not undergo torsion. The analytic function of the boundary of the airfoil is obtained by using the cubic spline interpolation since it is given in the form of tabulated points.

A standardized procedure for eddy-current testing of stainless steel, thin-walled nuclear fuel element cladding tubes

International Nuclear Information System (INIS)

Barat, P.; Raj, B.; Bhattacharya, D.K.

1982-01-01

Thin-walled nuclear fuel cladding tubes made of AISI 316 stainless steel have been examined by eddy-current testing. Standardization of the procedures has required investigations on optimizing the test frequency, finding a method to locate a defect with respect to the probe reference end, and the use of standard defects and sequential metallography of natural defects detected by eddy-current testing, to understand the influence of the nature of defects on the impedance output signals. Test frequency and method of locating the defect were optimized by the use of standard defects made by machining in reference cladding tubes. Subsequent metallography of natural defects detected by eddy-current testing revealed mainly clusters of inclusions but also other types of defects. The effect of the distribution of inclusions along the length of the tube on the impedance output is discussed. (author)

Cell wall and DNA cosegregation in Bacillus subtilis studied by electron microscope autoradiography

International Nuclear Information System (INIS)

Schlaeppi, J.M.; Schaefer, O.; Karamata, D.

1985-01-01

Cells of a Bacillus subtilis mutant deficient in both major autolytic enzyme activities were continuously labeled in either cell wall or DNA or both cell wall and DNA. After appropriate periods of chase in minimal as well as in rich medium, thin sections of cells were autoradiographed and examined by electron microscopy. The resolution of the method was adequate to distinguish labeled DNA units from cell wall units. The latter, which could be easily identified, were shown to segregate symmetrically, suggesting a zonal mode of new wall insertion. DNA units could also be clearly recognized despite a limited fragmentation; they segregated asymmetrically with respect to the nearest septum. Analysis of cells simultaneously labeled in cell wall and DNA provided clear visual evidence of their regular but asymmetrical cosegregation, confirming a previous report obtained by light microscope autoradiography. In addition to labeled wall units, electron microscopy of thin sections of aligned cells has revealed fibrillar networks of wall material which are frequently associated with the cell surface. Most likely, these structures correspond to wall sloughed off by the turnover mechanism but not yet degraded to filterable or acid-soluble components

R(and)D on full tungsten divertor and beryllium wall for JET ITER-like Wall Project

International Nuclear Information System (INIS)

Hirai, T.; Maier, H.; Rubel, M.

2006-01-01

The ITER-like Wall Project was initiated at JET, with the goal of testing the reference material combination chosen for ITER: beryllium (Be) in the main chamber (wall and limiters) and tungsten (W) in the divertor. The major aims are to study the tritium retention, material mixing, melt layer behavior and to optimize plasma operation scenarios with a full metal wall. The project requires major design and engineering efforts in R(and)D: (i) bulk W tile, (ii) W coatings on carbon fibre composites (CFC) (iii) Be coatings on Inconel, (iv) Be marker tiles. For the W divertor, two R(and)D tasks were initiated: (1) development of a conceptual design for a bulk W tile as the main outer divertor target plate, and (2) W coating selection from 14 different samples produced by various techniques for the other divertor plates and neutral beam shine. The bulk W tile must withstand power loads of 7 MW/m 2 for 10 s. JET divertor plates are not actively cooled, therefore, heat capacity of the tiles is an important design parameter. In addition to power handling, mechanical structural stability under electromagnetic forces and compatibility with remote handling are the key requirements in the design. The design has been completed. The test-tile survived 100 pulses at 7 MW/m 2 for 10 s in the electron beam facility, JUDITH. The W coatings with different thickness, thin ( 2 and 200 pulses at 10 MW/m 2 for 5 s. In all tested samples cracks developed perpendicularly to the fiber bundles in CFC because of contraction of the coating in the cooling phase. Coatings were also exposed to 1000 ELM-like loading pulses. The thin coatings showed fatigue leading to delamination, whereas for thick coatings better resistance in ELM-like loading. As a result of R(and)D a full W divertor was decided: bulk metal at the outer divertor and W coating at other areas. Be-related R(and)D activities are in two areas. Production of 8-9 μm layers on inner wall cladding Inconel tiles ensures the full coating of

A film-based wall shear stress sensor for wall-bounded turbulent flows

Science.gov (United States)

Amili, Omid; Soria, Julio

2011-07-01

In wall-bounded turbulent flows, determination of wall shear stress is an important task. The main objective of the present work is to develop a sensor which is capable of measuring surface shear stress over an extended region applicable to wall-bounded turbulent flows. This sensor, as a direct method for measuring wall shear stress, consists of mounting a thin flexible film on the solid surface. The sensor is made of a homogeneous, isotropic, and incompressible material. The geometry and mechanical properties of the film are measured, and particles with the nominal size of 11 μm in diameter are embedded on the film's surface to act as markers. An optical technique is used to measure the film deformation caused by the flow. The film has typically deflection of less than 2% of the material thickness under maximum loading. The sensor sensitivity can be adjusted by changing the thickness of the layer or the shear modulus of the film's material. The paper reports the sensor fabrication, static and dynamic calibration procedure, and its application to a fully developed turbulent channel flow at Reynolds numbers in the range of 90,000-130,000 based on the bulk velocity and channel full height. The results are compared to alternative wall shear stress measurement methods.

Mount Protects Thin-Walled Glass or Ceramic Tubes from Large Thermal and Vibration Loads

Science.gov (United States)

Amato, Michael; Schmidt, Stephen; Marsh. James; Dahya, Kevin

2011-01-01

The design allows for the low-stress mounting of fragile objects, like thin walled glass, by using particular ways of compensating, isolating, or releasing the coefficient of thermal expansion (CTE) differences between the mounted object and the mount itself. This mount profile is lower than true full kinematic mounting. Also, this approach enables accurate positioning of the component for electrical and optical interfaces. It avoids the higher and unpredictable stress issues that often result from potting the object. The mount has been built and tested to space-flight specifications, and has been used for fiber-optic, optical, and electrical interfaces for a spaceflight mission. This mount design is often metal and is slightly larger than the object to be mounted. The objects are optical or optical/electrical, and optical and/or electrical interfaces are required from the top and bottom. This requires the mount to be open at both ends, and for the object s position to be controlled. Thin inside inserts at the top and bottom contact the housing at defined lips, or edges, and hold the fragile object in the mount. The inserts can be customized to mimic the outer surface of the object, which further reduces stress. The inserts have the opposite CTE of the housing material, partially compensating for the CTE difference that causes thermal stress. A spring washer is inserted at one end to compensate for more CTE difference and to hold the object against the location edge of the mount for any optical position requirements. The spring also ensures that any fiber-optic or optic interface, which often requires some pressure to ensure a good interface, does not overstress the fragile object. The insert thickness, material, and spring washer size can be traded against each other to optimize the mount and stresses for various thermal and vibration load ranges and other mounting requirements. The alternate design uses two separate, unique features to reduce stress and hold the

Calculation on cosmic-ray muon exposure rate in non-walled concrete buildings

International Nuclear Information System (INIS)

Fujitaka, Kazunobu; Abe, Siro

1984-01-01

Computer simulations on the exposure indoors from cosmic ray muons were practiced in the framework of non-scattering and non-cascade assumptions. The model buildings were two-dimensional, rectangular, and were made of a normal concrete. A stratified structure was assumed in each building, where no mezzanine was considered. Walls were not taken into account yet. The distributions of the exposure rates in 26-story buildings were illustrated in contour maps for various sets of parameters. All of them gave basically archlike patterns. Analyses of the results showed that the exposure rate is affected most largely by the floor board thickness. The ceiling height would be an insignificant factor for short buildings. The min/max ratio of the muon exposure rate in a moderate size building was estimated to be more than 0.7. (author)

Development of a low Reynolds number turbulence stress and heat flux equation model. A new type wall boundary condition for dissipation rate of turbulent kinetic energy aided by DNS data base

International Nuclear Information System (INIS)

Nishimura, M.

1998-04-01

To predict thermal-hydraulic phenomena in actual plant under various conditions accurately, adequate simulation of laminar-turbulent flow transition is of importance. A low Reynolds number turbulence model is commonly used for a numerical simulation of the laminar-turbulent transition. The existing low Reynolds number turbulence models generally demands very thin mesh width between a wall and a first computational node from the wall, to keep accuracy and stability of numerical analyses. There is a criterion for the distance between the wall and the first computational node in which non-dimensional distance y + must be less than 0.5. Due to this criterion the suitable distance depends on Reynolds number. A liquid metal sodium is used for a coolant in first reactors therefore, Reynolds number is usually one or two order higher than that of the usual plants in which air and water are used for the work fluid. This makes the load of thermal-hydraulic numerical simulation of the liquid sodium relatively heavier. From above context, a new method is proposed for providing wall boundary condition of turbulent kinetic energy dissipation rate ε. The present method enables the wall-first node distance 10 times larger compared to the existing models. A function of the ε wall boundary condition has been constructed aided by a direct numerical simulation (DNS) data base. The method was validated through calculations of a turbulent Couette flow and a fully developed pipe flow and its laminar-turbulent transition. Thus the present method and modeling are capable of predicting the laminar-turbulent transition with less mesh numbers i.e. lighter computational loads. (J.P.N.)

Study of failure criterion applicable to elastic-plastic finite element analyses of wall-thinned pipes subjected to multi-axial loading. Case for groove type flaw under combined internal pressure and bending loading

International Nuclear Information System (INIS)

Mori, Kosuke; Meshii, Toshiyuki

2015-01-01

In this paper, a failure criterion applicable to large-strain finite element analysis (FEA) results was studied to predict the limit bending load M_c of the groove shaped wall-thinned pipes, under combined internal pressure and bending load, that experienced cracking. In our previous studies, Meshii and Ito (2012) considered cracking of pipes with groove shaped flaw (small axial length δ_z in Fig. 1) was due to the plastic instability at the wall-thinned section and proposed the Domain Collapse Criterion (DCC). The DCC could predict M_c of cracking for small δ_z by comparing the von Mises stress σ_M_i_s_e_s with the true tensile strength σ_B. Because the discrepancy in prediction of the M_c in the case of cracking was within 15%, it was considered that the predictability was could be improved further. Thus, in this work, attempt was made to improve the accuracy of M_c prediction with a perspective that multi-axial stress state might affect this plastic instability at the wall-thinned section. As a result of examination of the various failure criteria based on multi-axial stress, it was confirmed that the limit bending load of the groove flawed pipe that experienced cracking in experiment (Hereafter, it was expressed 'flawed pipe that experienced cracking') could be predicted within 5% accuracy by applying Hill's plastic instability onset criterion (Hill, 1952) to the outer surface of the crack penetration section. The accuracy of the predicted limit bending load was improved from DCC's within 15% to within 5%. (author)

A system of two piezoelectric transducers and a storage circuit for wireless energy transmission through a thin metal wall.

Science.gov (United States)

Hu, Hongping; Hu, Yuantai; Chen, Chuanyao; Wang, Ji

2008-10-01

A system to wirelessly convey electric energy through a thin metal wall is proposed in the paper, where 2 piezoelectric transducers are used to realize energy transformation between electric and mechanical, and a rechargeable battery is employed to store the transmitted energy. To integrate them as a whole, an interface of a modulating circuit is applied between the transducer system and the storage battery. In addition, a synchronized switch harvesting on inductor in parallel with the transducer system is introduced to artificially extend the closed interval of the modulating circuit. The process of transmitting energy is computed, and the performance of the transducer system is optimized in detail for a prescribed external electric source. The results obtained are useful for understanding and designing wireless energy supply systems.

Nanosphere lithography applied to magnetic thin films

Science.gov (United States)

Gleason, Russell

Magnetic nanostructures have widespread applications in many areas of physics and engineering, and nanosphere lithography has recently emerged as promising tool for the fabrication of such nanostructures. The goal of this research is to explore the magnetic properties of a thin film of ferromagnetic material deposited onto a hexagonally close-packed monolayer array of polystyrene nanospheres, and how they differ from the magnetic properties of a typical flat thin film. The first portion of this research focuses on determining the optimum conditions for depositing a monolayer of nanospheres onto chemically pretreated silicon substrates (via drop-coating) and the subsequent characterization of the deposited nanosphere layer with scanning electron microscopy. Single layers of permalloy (Ni80Fe20) are then deposited on top of the nanosphere array via DC magnetron sputtering, resulting in a thin film array of magnetic nanocaps. The coercivities of the thin films are measured using a home-built magneto-optical Kerr effect (MOKE) system in longitudinal arrangement. MOKE measurements show that for a single layer of permalloy (Py), the coercivity of a thin film deposited onto an array of nanospheres increases compared to that of a flat thin film. In addition, the coercivity increases as the nanosphere size decreases for the same deposited layer. It is postulated that magnetic exchange decoupling between neighboring nanocaps suppresses the propagation of magnetic domain walls, and this pinning of the domain walls is thought to be the primary source of the increase in coercivity.

Dynamics of domain wall driven by spin-transfer torque

International Nuclear Information System (INIS)

Chureemart, P.; Evans, R. F. L.; Chantrell, R. W.

2011-01-01

Spin-torque switching of magnetic devices offers new technological possibilities for data storage and integrated circuits. We have investigated domain-wall motion in a ferromagnetic thin film driven by a spin-polarized current using an atomistic spin model with a modified Landau-Lifshitz-Gilbert equation including the effect of the spin-transfer torque. The presence of the spin-transfer torque is shown to create an out-of-plane domain wall, in contrast to the external-field-driven case where an in-plane wall is found. We have investigated the effect of the spin torque on domain-wall displacement, domain-wall velocity, and domain-wall width, as well as the equilibration time in the presence of the spin-transfer torque. We have shown that the minimum spin-current density, regarded as the critical value for domain-wall motion, decreases with increasing temperature.

Method and apparatus for active control of combustion rate through modulation of heat transfer from the combustion chamber wall

Science.gov (United States)

Roberts, Jr., Charles E.; Chadwell, Christopher J.

2004-09-21

The flame propagation rate resulting from a combustion event in the combustion chamber of an internal combustion engine is controlled by modulation of the heat transfer from the combustion flame to the combustion chamber walls. In one embodiment, heat transfer from the combustion flame to the combustion chamber walls is mechanically modulated by a movable member that is inserted into, or withdrawn from, the combustion chamber thereby changing the shape of the combustion chamber and the combustion chamber wall surface area. In another embodiment, heat transfer from the combustion flame to the combustion chamber walls is modulated by cooling the surface of a portion of the combustion chamber wall that is in close proximity to the area of the combustion chamber where flame speed control is desired.

Review of techniques and detectors used in instruments for field measurement of β doses and dose rates

International Nuclear Information System (INIS)

Jones, A.R.

1984-01-01

Generally, field measurements are required to assess the hazard from β-rays before personnel are allowed to occupy a working space or perform a task. Occasionally, the measurements are required for an assessment after a β-ray exposure is suspected to have occurred. With these uses of field instruments in mind, the following detectors and associated techniques will be discussed in terms of the measurement principles, advantages, and limitations: 1) thin-walled ion chambers (sometimes in combination with thick-walled ones or with covers thick enough to prevent penetration of β-particles); 2) thin scintillators, nearly tissue equivalent, to provide a detector analogous to skin; 3) scintillators, thick enough to absorb all the energy of the β-particles. Circuitry is required to count pulses according to size to permit calculation of dose or dose rate; 4) silicon diodes with thin detection layers operated as photocurrent generators; 5) silicon diodes, reversed biassed, with pulses counted according to size; 6) simple pulse counters (e.g., GM counters or silicon diodes with thin windows)

High rate deposition of thin film cadmium sulphide by pulsed direct current magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Lisco, F., E-mail: F.Lisco@lboro.ac.uk [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Kaminski, P.M.; Abbas, A.; Bowers, J.W.; Claudio, G. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Losurdo, M. [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR, via Orabona 4, 70126 Bari (Italy); Walls, J.M. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

2015-01-01

Cadmium Sulphide (CdS) is an important n-type semiconductor widely used as a window layer in thin film photovoltaics Copper Indium Selenide, Copper Indium Gallium (di)Selenide, Copper Zinc Tin Sulphide and Cadmium Telluride (CdTe). Cadmium Sulphide has been deposited using a number of techniques but these techniques can be slow (chemical bath deposition and Radio Frequency sputtering) or the uniformity and the control of thickness can be relatively difficult (close space sublimation). In this paper we report on the development of a process using pulsed Direct Current magnetron sputtering which allows nanometre control of thin film thickness using time only. The CdS thin films deposited in this process are highly uniform and smooth. They exhibit the preferred hexagonal structure at room temperature deposition and they have excellent optical properties. Importantly, the process is highly stable despite the use of a semi-insulating magnetron target. Moreover, the process is very fast. The deposition rate using 1.5 kW of power to a 6-inch circular magnetron was measured to be greater than 8 nm/s. This makes the process suitable for industrial deployment. - Highlights: • Pulsed DC magnetron sputtering of CdS • High deposition rate deposition • Uniform, pinhole free films.

High rate deposition of thin film cadmium sulphide by pulsed direct current magnetron sputtering

International Nuclear Information System (INIS)

Lisco, F.; Kaminski, P.M.; Abbas, A.; Bowers, J.W.; Claudio, G.; Losurdo, M.; Walls, J.M.

2015-01-01

Cadmium Sulphide (CdS) is an important n-type semiconductor widely used as a window layer in thin film photovoltaics Copper Indium Selenide, Copper Indium Gallium (di)Selenide, Copper Zinc Tin Sulphide and Cadmium Telluride (CdTe). Cadmium Sulphide has been deposited using a number of techniques but these techniques can be slow (chemical bath deposition and Radio Frequency sputtering) or the uniformity and the control of thickness can be relatively difficult (close space sublimation). In this paper we report on the development of a process using pulsed Direct Current magnetron sputtering which allows nanometre control of thin film thickness using time only. The CdS thin films deposited in this process are highly uniform and smooth. They exhibit the preferred hexagonal structure at room temperature deposition and they have excellent optical properties. Importantly, the process is highly stable despite the use of a semi-insulating magnetron target. Moreover, the process is very fast. The deposition rate using 1.5 kW of power to a 6-inch circular magnetron was measured to be greater than 8 nm/s. This makes the process suitable for industrial deployment. - Highlights: • Pulsed DC magnetron sputtering of CdS • High deposition rate deposition • Uniform, pinhole free films

Novel Adaptive Fixturing for Thin Walled Aerospace Parts

International Nuclear Information System (INIS)

Merlo, Angelo; Ricciardi, Donato; Salvi, Edoardo; Fantinati, Dario; Iorio, Ernesto

2011-01-01

In the aerospace industry the monolithic structures have been introduced to reduce the costs of assembling large numbers of components. The expected benefit of using thin walled monolithic parts is given by a large reduction in the overall manufacturing costs, nevertheless this kind of component encounters a critical phase in fixturing. Fixtures are used to locate and hold workpieces during manufacturing. Because workpiece surface errors and fixture set-up errors (called source errors) always exist, the fixtured workpiece will consequently have position and/or orientation errors (called resultant errors) that will definitely affect the final machining accuracy. Most often the current clamping procedure is not straightforward, it implies several steps and the success of the operation hardly depends by the skill of the human operator. It is estimated that fixturing could constitute 10-20% of the total manufacturing costs, assuming that the fixtures are amortized over relatively small batches. Fixturing devices must satisfy two requisites, which, in some terms, are opposite: - to provide relatively high forces in order to guarantee that the workpiece will be maintained in position under the maximum cutting forces; - to reduce as much as possible strains induced in the workpiece. Limiting the strains induced in the workpiece is crucial because of elastic strain recovery: releasing the clamped workpiece would result in an unwanted final deformation. In this paper a novel adaptive fixturing based on active clamping forces (supplied by piezoelectric actuators) is presented: a real aerospace part case study, - a Nozzle Guide Vane (NGV) -, is introduced, the related problems are identified, and the adopted solutions shown. The proposed adaptive fixturing device can lead to the following advantages: - to perform an automatic errors-free workpiece clamping and then drastically reduce the overall fixturing set up time; - to recover unwanted strains induced to the workpiece, in

Controlling effective aspect ratio and packing of clay with pH for improved gas barrier in nanobrick wall thin films.

Science.gov (United States)

Hagen, David A; Saucier, Lauren; Grunlan, Jaime C

2014-12-24

Polymer-clay thin films constructed via layer-by-layer (LbL) assembly, with a nanobrick wall structure (i.e., clay nanoplatelets as bricks surrounded by a polyelectrolyte mortar), are known to exhibit a high oxygen barrier. Further barrier improvement can be achieved by lowering the pH of the clay suspension in the polyethylenimine (PEI) and montmorillonite (MMT) system. In this case, the charge of the deposited PEI layer is increased in the clay suspension environment, which causes more clay to be deposited. At pH 4, MMT platelets deposit with near perfect ordering, observed with transmission electron microscopy, enabling a 5× improvement in the gas barrier for a 10 PEI/MMT bilayer thin film (85 nm) relative to the same film made with pH 10 MMT. This improved gas barrier approaches that achieved with much higher aspect ratio vermiculite clay. In essence, lower pH is generating a higher effective aspect ratio for MMT due to greater induced surface charge in the PEI layers, which causes heavier clay deposition. These flexible, transparent nanocoatings have a wide range of possible applications, from food and electronics packaging to pressurized bladders.

Thin layer activation

International Nuclear Information System (INIS)

Schweickert, H.; Fehsenfeld, P.

1995-01-01

The reliability of industrial equip ment is substantially influenced by wear and corrosion; monitoring can prevent accidents and avoid down-time. One powerful tool is thin layer activation analysis (TLA) using accelerator systems. The information is used to improve mechanical design and material usage; the technology is used by many large companies, particularly in the automotive industry, e.g. Daimler Benz. A critical area of a machine component receives a thin layer of radioactivity by irradiation with charged particles from an accelerator - usually a cyclotron. The radioactivity can be made homogeneous by suitable selection of particle, beam energy and angle of incidence. Layer thickness can be varied from 20 microns to around 1 mm with different depth distributions; the position and size of the wear zone can be set to within 0.1 mm. The machine is then reassembled and operated so that wear can be measured. An example is a combustion engine comprising piston ring, cylinder wall, cooling water jacket and housing wall, where wear measurements on the cylinder wall are required in a critical zone around the dead-point of the piston ring. Proton beam bombardment creates a radioactive layer whose thickness is known accurately, and characteristic gamma radiation from this radioactive zone penetrates through the engine and is detected externally. Measurements can be made either of the activity removed from the surface, or of the (reduced) residual activity; wear measurement of the order of 10 -9 metres is possible

Resistive wall instabilities and tearing mode dynamics in the EXTRAP T2R thin shell reversed-field pinch

Science.gov (United States)

Malmberg, J.-A.; Brunsell, P. R.

2002-01-01

Observations of resistive wall instabilities and tearing mode dynamics in the EXTRAP T2R thin shell (τw=6 ms) reversed field pinch are described. A nonresonant mode (m=1,n=-10) with the same handedness as the internal field grows nearly exponentially with an average growth time of about 2.6 ms (less than 1/2 of the shell time) consistent with linear stability theory. The externally nonresonant unstable modes (m=1,n>0), predicted by linear stability theory, are observed to have only low amplitudes (in the normal low-Θ operation mode of the device). The radial field of the dominant internally resonant tearing modes (m=1,n=-15 to n=-12) remain low due to spontaneous fast mode rotation, corresponding to angular phase velocities up to 280 krad/s. Phase aligned mode structures are observed to rotate toroidally with an average angular velocity of 40 krad/s, in the opposite direction of the plasma current. Toward the end of the discharge, the radial field of the internally resonant modes grows as the modes slow down and become wall-locked, in agreement with nonlinear computations. Fast rotation of the internally resonant modes has been observed only recently and is attributed to a change of the front-end system (vacuum vessel, shell, and TF coil) of the device.

Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes/polymer composite thin film.

Science.gov (United States)

Rajanna, Pramod Mulbagal; Gilshteyn, Evgenia; Yagafarov, Timur; Alekseeva, Alena; Anisimov, Anton; Sergeev, Oleg; Neumueller, Alex; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert

2018-01-09

We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and a thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high quality SWCNTs with an enhanced conductivity by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with different SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit Jsc, open-circuit Voc, and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and efficiency of 3.4% under simulated one-sun AM 1.5G direct illumination. © 2018 IOP Publishing Ltd.

Multifractal characterization of single wall carbon nanotube thin films surface upon exposure to optical parametric oscillator laser irradiation

International Nuclear Information System (INIS)

Ţălu, Ştefan; Marković, Zoran; Stach, Sebastian; Todorović Marković, B.; Ţălu, Mihai

2014-01-01

This study presents a multifractal approach, obtained with atomic force microscopy analysis, to characterize the structural evolution of single wall carbon nanotube thin films upon exposure to optical parametric oscillator laser irradiation at wavelength of 430 nm. Microstructure and morphological changes of carbon nanotube films deposited on different substrates (mica and TGX grating) were recorded by atomic force microscope. A detailed methodology for surface multifractal characterization, which may be applied for atomic force microscopy data, was presented. Multifractal analysis of surface roughness revealed that carbon nanotube films surface has a multifractal geometry at various magnifications. The generalized dimension D q and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of carbon nanotube films surface morphology at nanometer scale. Multifractal analysis provides different yet complementary information to that offered by traditional surface statistical parameters.

The rate of thermal expansion of a thin metallic slab of arbitrary shape.

Science.gov (United States)

Lee, Y C

2009-08-12

In a previous paper the rate of thermal expansion of a long, slender insulating bar has been worked out. Our present aim is to extend that work to the thermal expansion rate of not only a long metallic bar, but to further generalize it to a thin metallic slab of arbitrary shape. Assuming that the thickness of the slab is small compared to the linear dimension of its area we again take advantage of the two distinct, disparate timescales to turn the familiar problem of thermal expansion into a time-dependent problem of the rate of the expansion. Based on the previously established finite physical momentum of an acoustic phonon when translational invariance is broken, we show that the combined pressure of the phonons and the free electrons due to their outward momenta would suffer a Doppler reduction as the specimen expands upon heating. This Doppler reduction gives rise to damping of the expanding motion, thus yielding as a first result the time of thermal expansion of a long slender metal bar. The generalization to the important case of a thin metallic slab of any shape is then worked out in detail before a concluding section containing a long physical discussion and summary.

Methods and results for stress analyses on 14-ton, thin-wall depleted UF6 cylinders

International Nuclear Information System (INIS)

Kirkpatrick, J.R.; Chung, C.K.; Frazier, J.L.; Kelley, D.K.

1996-10-01

Uranium enrichment operations at the three US gaseous diffusion plants produce depleted uranium hexafluoride (DUF 6 ) as a residential product. At the present time, the inventory of DUF 6 in this country is more than half a million tons. The inventory of DUF 6 is contained in metal storage cylinders, most of which are located at the gaseous diffusion plants. The principal objective of the project is to ensure the integrity of the cylinders to prevent causing an environmental hazard by releasing the contents of the cylinders into the atmosphere. Another objective is to maintain the cylinders in such a manner that the DUF 6 may eventually be converted to a less hazardous material for final disposition. An important task in the DUF 6 cylinders management project is determining how much corrosion of the walls can be tolerated before the cylinders are in danger of being damaged during routine handling and shipping operations. Another task is determining how to handle cylinders that have already been damaged in a manner that will minimize the chance that a breach will occur or that the size of an existing breach will be significantly increased. A number of finite element stress analysis (FESA) calculations have been done to analyze the stresses for three conditions: (1) while the cylinder is being lifted, (2) when a cylinder is resting on two cylinders under it in the customary two-tier stacking array, and (3) when a cylinder is resting on tis chocks on the ground. Various documents describe some of the results and discuss some of the methods whereby they have been obtained. The objective of the present report is to document as many of the FESA cases done at Oak Ridge for 14-ton thin-wall cylinders as possible, giving results and a description of the calculations in some detail

High rate deposition of transparent conducting oxide thin films by vacuum arc plasma evaporation

International Nuclear Information System (INIS)

Minami, Tadatsugu; Ida, Satoshi; Miyata, Toshihiro

2002-01-01

Transparent conducting oxide (TCO) thin films have been deposited at a high rate above 370 nm/min by vacuum arc plasma evaporation (VAPE) using sintered oxide fragments as the source material. It was found that the deposition rate of TCO films was strongly dependent on the deposition pressure, whereas the obtained electrical properties were relatively independent of the pressure. Resistivities of 5.6x10 -4 and 2.3x10 -4 Ω·cm and an average transmittance above 80% (with substrate included) in the visible range were obtained in Ga-doped ZnO (GZO) thin films deposited at 100 and 350 deg. C, respectively. In addition, a resistivity as low as 1.4x10 -4 Ω·cm and an average transmittance above 80% were also obtained in indium-tin-oxide (ITO) films deposited at 300 deg. C. The deposited TCO films exhibited uniform distributions of resistivity and thickness on large area substrates

High rate deposition of transparent conducting oxide thin films by vacuum arc plasma evaporation

Energy Technology Data Exchange (ETDEWEB)

Minami, Tadatsugu; Ida, Satoshi; Miyata, Toshihiro

2002-09-02

Transparent conducting oxide (TCO) thin films have been deposited at a high rate above 370 nm/min by vacuum arc plasma evaporation (VAPE) using sintered oxide fragments as the source material. It was found that the deposition rate of TCO films was strongly dependent on the deposition pressure, whereas the obtained electrical properties were relatively independent of the pressure. Resistivities of 5.6x10{sup -4} and 2.3x10{sup -4} {omega}{center_dot}cm and an average transmittance above 80% (with substrate included) in the visible range were obtained in Ga-doped ZnO (GZO) thin films deposited at 100 and 350 deg. C, respectively. In addition, a resistivity as low as 1.4x10{sup -4} {omega}{center_dot}cm and an average transmittance above 80% were also obtained in indium-tin-oxide (ITO) films deposited at 300 deg. C. The deposited TCO films exhibited uniform distributions of resistivity and thickness on large area substrates.

Parameter-free method for the shape optimization of stiffeners on thin-walled structures to minimize stress concentration

Energy Technology Data Exchange (ETDEWEB)

Liu, Yang; Shibutan, Yoji [Osaka University, Osaka (Japan); Shimoda, Masatoshi [Toyota Technological Institute, Nagoya (Japan)

2015-04-15

This paper presents a parameter-free shape optimization method for the strength design of stiffeners on thin-walled structures. The maximum von Mises stress is minimized and subjected to the volume constraint. The optimum design problem is formulated as a distributed-parameter shape optimization problem under the assumptions that a stiffener is varied in the in-plane direction and that the thickness is constant. The issue of nondifferentiability, which is inherent in this min-max problem, is avoided by transforming the local measure to a smooth differentiable integral functional by using the Kreisselmeier-Steinhauser function. The shape gradient functions are derived by using the material derivative method and adjoint variable method and are applied to the H{sup 1} gradient method for shells to determine the optimal free-boundary shapes. By using this method, the smooth optimal stiffener shape can be obtained without any shape design parameterization while minimizing the maximum stress. The validity of this method is verified through two practical design examples.

Resistive wall modes in the EXTRAP T2R reversed-field pinch

Science.gov (United States)

Brunsell, P. R.; Malmberg, J.-A.; Yadikin, D.; Cecconello, M.

2003-10-01

Resistive wall modes (RWM) in the reversed field pinch are studied and a detailed comparison of experimental growth rates and linear magnetohydrodynamic (MHD) theory is made. RWM growth rates are experimentally measured in the thin shell device EXTRAP T2R [P. R. Brunsell et al., Plasma Phys. Controlled Fusion 43, 1 (2001)]. Linear MHD calculations of RWM growth rates are based on experimental equilibria. Experimental and linear MHD RWM growth rate dependency on the equilibrium profiles is investigated experimentally by varying the pinch parameter Θ=Bθ(a)/ in the range Θ=1.5-1.8. Quantitative agreement between experimental and linear MHD growth rates is seen. The dominating RWMs are the internal on-axis modes (having the same helicity as the central equilibrium field). At high Θ, external nonresonant modes are also observed. For internal modes experimental growth rates decrease with Θ while for external modes, growth rates increase with Θ. The effect of RWMs on the reversed-field pinch plasma performance is discussed.

Structural phase change and optical band gap bowing in hot wall deposited CdSe{sub x}Te{sub 1-x} thin films

Energy Technology Data Exchange (ETDEWEB)

Muthukumarasamy, N. [Department of Physics, Coimbatore Institute of Technology, Coimbatore, Tamilnadu (India); Jayakumar, S.; Kannan, M.D.; Balasundaraprabhu, R. [Thin Film Center, PSG College of Technology, Coimbatore, Tamilnadu (India)

2009-04-15

CdSe{sub x}Te{sub 1-x} thin films of different compositions have been deposited on glass substrates by hot wall deposition method under conditions very close to thermodynamical equilibrium with minimum loss of material. The structural studies carried out on the deposited films revealed that they are crystalline in nature and exhibit either cubic zinc blende or hexagonal phase or both depending on the composition of the material. The lattice parameter values for both cubic and hexagonal phases have been determined and are observed to vary with composition according to Vegard's law. The optical properties of the deposited CdSe{sub x}Te{sub 1-x} thin films have been studied using transmittance spectra. The spectra shows a sharp fall in transmittance at wavelength corresponding to the band gap of the material. The optical band gap has been determined and found to be direct allowed. The band gap has been observed to strongly depend on film composition. The variation of band gap with composition has been observed to be quadratic in nature exhibiting a bowing behaviour. (author)

Fabrication of thin-wall, freestanding inertial confinement fusion targets by chemical vapor deposition

International Nuclear Information System (INIS)

Carroll, D.W.; McCreary, W.J.

1982-01-01

To meet the requirements for plasma physics experiments in the inertial confinement fusion (ICF) program, chemical vapor deposition (CVD) in fluid beds was used to fabricate freestanding tungsten spheres and cylinders with wall thicknesses less than 5.0 μm. Molybdenum and molybdenum alloy (TZM) mandrels of the desired geometry were suspended in a carrier bed of dense microspheres contained in an induction-heated fluid-bed reactor. The mandrels were free to float randomly through the bed, and using the reaction WF 6 +3H 2 →/sub /KW +6HF, very fine-grained tungsten was deposited onto the surface at a rate and in a grain size determined by temperature, gas flow rate, system pressure, and duration of the reaction. After coating, a portion of each mandrel was exposed by hole drilling or grinding. The mandrel was then removed by acid leaching, leaving a freestanding tungsten shape. Experimental procedures, mandrel preparation, and results obtained are discussed

Tailoring of structural and electron emission properties of CNT walls and graphene layers using high-energy irradiation

International Nuclear Information System (INIS)

Sharma, Himani; Shukla, A K; Vankar, V D; Agarwal, Dinesh C; Avasthi, D K; Sharma, M

2013-01-01

Structural and electron emission properties of carbon nanotubes (CNTs) and multilayer graphene (MLG) are tailored using high-energy irradiation by controlling the wall thickness and number of layers. Ion irradiation by 100 MeV Ag + ions at different fluences is used as an effective tool for optimizing defect formation in CNTs and MLGs, as analysed by micro-Raman spectroscopy. It is found that the cross section for defect formation (η) is 3.5 × 10 −11 for thin-walled CNTs, 2.8 × 10 −11 for thick-walled CNTs and 3.1 × 10 −11 for MLGs. High-resolution transmission electron microscopy results also show that thin-walled CNTs and MLGs are more defective in comparison with thick-walled CNTs. Carbon atoms rearrange at a fluence of 1 × 10 12 ions cm −2 in thick-walled CNTs to heal up the damage, which aggravates at higher fluences. The observed electron emission parameters of the modified thin-walled CNTs and MLGs are confirmed with the changes in the structures and are optimized at a fluence of 1 × 10 11 ions cm −2 . However, the electron emission properties of thick-walled CNTs are modified at a fluence of 1 × 10 12 ions cm −2 . The enhancement in the electron emission properties is due to the rearrangement of bonds and hence modified tips due to irradiation. (paper)

Study on the effect of deposition rate and concentration of Eu on the fluorescent lifetime of CsI: Tl thin film

Energy Technology Data Exchange (ETDEWEB)

Xie, Yijun; Guo, Lina [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu 610054 (China); Liu, Shuang, E-mail: shuangliu@uestc.edu.cn [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu 610054 (China); Wang, Qianfeng; Zhang, Shangjian; Liu, Yong [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu 610054 (China); Zhong, Zhiyong [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, Chengdu 610054 (China)

2017-06-21

Although there are many new scintillators being developed recently, CsI: Tl is still very efficient among them. The fluorescent lifetime is a very important parameter of CsI: Tl thin film and two series of experiments have been conducted to learn about it. Our experiments, however, have demonstrated that the deposition rate and the codoping of Eu{sup 2+} will significantly influence its fluorescent lifetime. In order to increase the efficiency of the imaging system, we intend to obtain a higher fluorescent lifetime for CsI: Tl thin film by controlling these two conditions. - Highlights: • We used vacuum vapor deposition method to grow the high-quality thin films. • The relationship between the deposition rate and the fluorescent lifetime of CsI: Tl thin film was tested. • Concentration of Eu on fluorescent lifetime of the CsI: Tl thin film was studied.

High-rate deposition of epitaxial layers for efficient low-temperature thin film epitaxial silicon solar cells

Energy Technology Data Exchange (ETDEWEB)

Oberbeck, L.; Schmidt, J.; Wagner, T.A.; Bergmann, R.B. [Stuttgart Univ. (Germany). Inst. of Physical Electronics

2001-07-01

Low-temperature deposition of Si for thin-film solar cells has previously been hampered by low deposition rates and low material quality, usually reflected by a low open-circuit voltage of these solar cells. In contrast, ion-assisted deposition produces Si films with a minority-carrier diffusion length of 40 {mu}m, obtained at a record deposition rate of 0.8 {mu}m/min and a deposition temperature of 650{sup o}C with a prebake at 810{sup o}C. A thin-film Si solar cell with a 20-{mu}m-thick epitaxial layer achieves an open-circuit voltage of 622 mV and a conversion efficiency of 12.7% without any light trapping structures and without high-temperature solar cell process steps. (author)

Enhanced forward osmosis from chemically modified polybenzimidazole (PBI) nanofiltration hollow fiber membranes with a thin wall

KAUST Repository

Wang, Kai Yu; Yang, Qian; Chung, Tai-Shung; Rajagopalan, Raj

2009-01-01

To develop high-flux and high-rejection forward osmosis (FO) membranes for water reuses and seawater desalination, we have fabricated polybenzimidazole (PBI) nanofiltration (NF) hollow fiber membranes with a thin wall and a desired pore size via non-solvent induced phase inversion and chemically cross-linking modification. The cross-linking by p-xylylene dichloride can finely tune the mean pore size and enhance the salt selectivity. High water permeation flux and improved salt selectivity for water reuses were achieved by using the 2-h modified PBI NF membrane which has a narrow pore size distribution. Cross-linking at a longer time produces even a lower salt permeation flux potentially suitable for desalination but at the expense of permeation flux due to tightened pore sizes. It is found that draw solution concentration and membrane orientations are main factors determining the water permeation flux. In addition, effects of membrane morphology and operation conditions on water and salt transport through membrane have been investigated. © 2008 Elsevier Ltd. All rights reserved.

Enhanced forward osmosis from chemically modified polybenzimidazole (PBI) nanofiltration hollow fiber membranes with a thin wall

KAUST Repository

Wang, Kai Yu

2009-04-01

To develop high-flux and high-rejection forward osmosis (FO) membranes for water reuses and seawater desalination, we have fabricated polybenzimidazole (PBI) nanofiltration (NF) hollow fiber membranes with a thin wall and a desired pore size via non-solvent induced phase inversion and chemically cross-linking modification. The cross-linking by p-xylylene dichloride can finely tune the mean pore size and enhance the salt selectivity. High water permeation flux and improved salt selectivity for water reuses were achieved by using the 2-h modified PBI NF membrane which has a narrow pore size distribution. Cross-linking at a longer time produces even a lower salt permeation flux potentially suitable for desalination but at the expense of permeation flux due to tightened pore sizes. It is found that draw solution concentration and membrane orientations are main factors determining the water permeation flux. In addition, effects of membrane morphology and operation conditions on water and salt transport through membrane have been investigated. © 2008 Elsevier Ltd. All rights reserved.

DISTORTION ANALYSIS OF TILL -WALLED BOX GIRDERS

African Journals Online (AJOL)

NIJOTECH

bridges, buildings, motor vehicles, ships and aircrafts. Due to thinness of the box walls, generalized loads applied to this structure give rise to warping and distortion of ..... Recommendation for Design of. Intermediate Diaphragms in Box. Girders, Transactions of Japanese. Society of Civil Engineers, Vol. 14,1984, pp 121-126.

CURVED WALLS: GRAIN GROWTH, SETTLING, AND COMPOSITION PATTERNS IN T TAURI DISK DUST SUBLIMATION FRONTS

International Nuclear Information System (INIS)

McClure, M. K.; Calvet, N.; Hartmann, L.; Ingleby, L.; D'Alessio, P.; Espaillat, C.; Sargent, B.; Watson, D. M.; Hernández, J.

2013-01-01

The dust sublimation walls of disks around T Tauri stars represent a directly observable cross-section through the disk atmosphere and midplane. Their emission properties can probe the grain size distribution and composition of the innermost regions of the disk, where terrestrial planets form. Here we calculate the inner dust sublimation wall properties for four classical T Tauri stars with a narrow range of spectral types and inclination angles and a wide range of mass accretion rates to determine the extent to which the walls are radially curved. Best fits to the near- and mid-IR excesses are found for curved, two-layer walls in which the lower layer contains larger, hotter, amorphous pyroxene grains with Mg/(Mg+Fe) = 0.6 and the upper layer contains submicron, cooler, mixed amorphous olivine and forsterite grains. As the mass accretion rates decrease from 10 –8 to 10 –10 M ☉ yr –1 , the maximum grain size in the lower layer decreases from ∼3 to 0.5 μm. We attribute this to a decrease in fragmentation and turbulent support for micron-sized grains with decreasing viscous heating. The atmosphere of these disks is depleted of dust with dust-gas mass ratios 1 × 10 –4 of the interstellar medium (ISM) value, while the midplane is enhanced to eight times the ISM value. For all accretion rates, the wall contributes at least half of the flux in the optically thin 10 μm silicate feature. Finally, we find evidence for an iron gradient in the disk, suggestive of that found in our solar system

CURVED WALLS: GRAIN GROWTH, SETTLING, AND COMPOSITION PATTERNS IN T TAURI DISK DUST SUBLIMATION FRONTS

Energy Technology Data Exchange (ETDEWEB)

McClure, M. K.; Calvet, N.; Hartmann, L.; Ingleby, L. [Department of Astronomy, The University of Michigan, 500 Church Street, 830 Dennison Building., Ann Arbor, MI 48109 (United States); D' Alessio, P. [Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, 58089 Morelia, Michoacán (Mexico); Espaillat, C. [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Sargent, B. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Watson, D. M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Hernández, J., E-mail: melisma@umich.edu, E-mail: ncalvet@umich.edu, E-mail: lhartm@umich.edu, E-mail: lingleby@umich.edu, E-mail: p.dalessio@astrosmo.unam.mx, E-mail: cespaillat@cfa.harvard.edu, E-mail: baspci@rit.edu, E-mail: dmw@pas.rochester.edu, E-mail: hernandj@cida.ve [Centro de Investigaciones de Astronomía (CIDA), Mérida 5101-A (Venezuela, Bolivarian Republic of)

2013-10-01

The dust sublimation walls of disks around T Tauri stars represent a directly observable cross-section through the disk atmosphere and midplane. Their emission properties can probe the grain size distribution and composition of the innermost regions of the disk, where terrestrial planets form. Here we calculate the inner dust sublimation wall properties for four classical T Tauri stars with a narrow range of spectral types and inclination angles and a wide range of mass accretion rates to determine the extent to which the walls are radially curved. Best fits to the near- and mid-IR excesses are found for curved, two-layer walls in which the lower layer contains larger, hotter, amorphous pyroxene grains with Mg/(Mg+Fe) = 0.6 and the upper layer contains submicron, cooler, mixed amorphous olivine and forsterite grains. As the mass accretion rates decrease from 10{sup –8} to 10{sup –10} M{sub ☉} yr{sup –1}, the maximum grain size in the lower layer decreases from ∼3 to 0.5 μm. We attribute this to a decrease in fragmentation and turbulent support for micron-sized grains with decreasing viscous heating. The atmosphere of these disks is depleted of dust with dust-gas mass ratios 1 × 10{sup –4} of the interstellar medium (ISM) value, while the midplane is enhanced to eight times the ISM value. For all accretion rates, the wall contributes at least half of the flux in the optically thin 10 μm silicate feature. Finally, we find evidence for an iron gradient in the disk, suggestive of that found in our solar system.

Intraventricular filling under increasing left ventricular wall stiffness and heart rates

Science.gov (United States)

Samaee, Milad; Lai, Hong Kuan; Schovanec, Joseph; Santhanakrishnan, Arvind; Nagueh, Sherif

2015-11-01

Heart failure with normal ejection fraction (HFNEF) is a clinical syndrome that is prevalent in over 50% of heart failure patients. HFNEF patients show increased left ventricle (LV) wall stiffness and clinical diagnosis is difficult using ejection fraction (EF) measurements. We hypothesized that filling vortex circulation strength would decrease with increasing LV stiffness irrespective of heart rate (HR). 2D PIV and hemodynamic measurements were acquired on LV physical models of varying wall stiffness under resting and exercise HRs. The LV models were comparatively tested in an in vitro flow circuit consisting of a two-element Windkessel model driven by a piston pump. The stiffer LV models were tested in comparison with the least stiff baseline model without changing pump amplitude, circuit compliance and resistance. Increasing stiffness at resting HR resulted in diminishing cardiac output without lowering EF below 50% as in HFNEF. Increasing HR to 110 bpm in addition to stiffness resulted in lowering EF to less than 50%. The circulation strength of the intraventricular filling vortex diminished with increasing stiffness and HR. The results suggest that filling vortex circulation strength could be potentially used as a surrogate measure of LV stiffness. This research was supported by the Oklahoma Center for Advancement of Science and Technology (HR14-022).

Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes and polymer composite thin film

Science.gov (United States)

Rajanna, Pramod M.; Gilshteyn, Evgenia P.; Yagafarov, Timur; Aleekseeva, Alena K.; Anisimov, Anton S.; Neumüller, Alex; Sergeev, Oleg; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert G.

2018-03-01

We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high-quality SWCNTs with conductivity enhanced by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with varying SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit J sc , open-circuit V oc , and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and an efficiency of 3.4% under simulated one-sun AM 1.5 G direct illumination.

An Evaluation of the Use of Simulated Annealing to Optimize Thinning Rates for Single Even-Aged Stands

Directory of Open Access Journals (Sweden)

Kai Moriguchi

2015-01-01

Full Text Available We evaluated the potential of simulated annealing as a reliable method for optimizing thinning rates for single even-aged stands. Four types of yield models were used as benchmark models to examine the algorithm’s versatility. Thinning rate, which was constrained to 0–50% every 5 years at stand ages of 10–45 years, was optimized to maximize the net present value for one fixed rotation term (50 years. The best parameters for the simulated annealing were chosen from 113 patterns, using the mean of the net present value from 39 runs to ensure the best performance. We compared the solutions with those from coarse full enumeration to evaluate the method’s reliability and with 39 runs of random search to evaluate its efficiency. In contrast to random search, the best run of simulated annealing for each of the four yield models resulted in a better solution than coarse full enumeration. However, variations in the objective function for two yield models obtained with simulated annealing were significantly larger than those of random search. In conclusion, simulated annealing with optimized parameters is more efficient for optimizing thinning rates than random search. However, it is necessary to execute multiple runs to obtain reliable solutions.

The influence of triggers geometry upon the stiffness of cylindrical thin walled tubes

Science.gov (United States)

Soica, Adrian; Radu, Gheorghe N.

2014-06-01

Today's automobile manufacturers are increasingly using lightweight materials to reduce weight; these include plastics, composites, aluminium, magnesium alloys, and also new types of high strength steels. Many of these materials have limited strength or ductility, therefore in many cases the rupture being serious consequences during crashes, underscore Picketta et al. in their studies. Automotive structures must deform plastically in a short period of time, a few milliseconds, to absorb the crash energy in a controllable manner. It must be light and enable economically mass-production [1]. FE models rapidly gained acceptance among engineers. Many other factors facilitated the development of vehicle models by shell finite elements since most of the geometry of the structural surfaces was already on computer graphic files. Kee Poong Kim and Hoon Huh emphasize that the crashworthiness of each vehicle part needs to be evaluated at the initial stage of design for good performance of an assembled vehicle. As the dynamic behaviour of structural members is different from the static one, the crashworthiness of the vehicle structures has to be assessed by impact analysis. The paper analyzes the influence of trigger geometry upon the compression of thin-walled cylindrical tubes. Simulations performed on a simple model showed the dependence between triggers area and deformation times as well as the maximum deformations obtained for various speeds at which the simulations ware carried out. Likewise, the geometry of trigger leads to different results.

Experimental study of the leakage rate through cracked reinforced concrete wall elements for defining the functional failure criteria of containment buildings

International Nuclear Information System (INIS)

Choun, Young Sun; Cho, Nam So

2004-01-01

Containment buildings in nuclear power plants should maintain their structural safety as well as their functional integrity during an operation period. To maintain the functional integrity, the wall and dome of the containment buildings have to maintain their air tightness under extreme loading conditions such as earthquakes, missile impact, and severe accidents. For evaluating the functional failure of containments, it is important to predict the leak amount through cracked concrete walls. The leakage through concrete cracks has been studied since 1972. Buss examined the flow rate of air through a pre-existing crack in a slab under air pressure. Rizkalla el al. initiated an experimental study for the leakage of prestressed concrete building segments under uniaxial and biaxial loadings to simulate the loading condition of containment buildings under an internal pressure. Recently, Salmon el al. initiated an experimental program for determining the leak rates in typical reinforced concrete shear walls subjected to beyond design basis earthquakes. This study investigates the cracking behavior of reinforced concrete containment wall elements under a uniaxial tension and addresses the outline of the leakage test for unlined containment wall elements

Rib fracture after stereotactic radiotherapy on follow-up thin-section computed tomography in 177 primary lung cancer patients

International Nuclear Information System (INIS)

Nambu, Atsushi; Tominaga, Lichto; Maehata, Yoshiyasu; Sawada, Eiichi; Araki, Tsutomu; Onishi, Hiroshi; Aoki, Shinichi; Koshiishi, Tsuyota; Kuriyama, Kengo; Komiyama, Takafumi; Marino, Kan; Araya, Masayuki; Saito, Ryo

2011-01-01

Chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer has recently been reported. However, its detailed imaging findings are not clarified. So this study aimed to fully characterize the findings on computed tomography (CT), appearance time and frequency of chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer A total of 177 patients who had undergone SRT were prospectively evaluated for periodical follow-up thin-section CT with special attention to chest wall injury. The time at which CT findings of chest wall injury appeared was assessed. Related clinical symptoms were also evaluated. Rib fracture was identified on follow-up CT in 41 patients (23.2%). Rib fractures appeared at a mean of 21.2 months after the completion of SRT (range, 4 -58 months). Chest wall edema, thinning of the cortex and osteosclerosis were findings frequently associated with, and tending to precede rib fractures. No patients with rib fracture showed tumors > 16 mm from the adjacent chest wall. Chest wall pain was seen in 18 of 177 patients (10.2%), of whom 14 patients developed rib fracture. No patients complained of Grade 3 or more symptoms. Rib fracture is frequently seen after SRT for lung cancer on CT, and is often associated with chest wall edema, thinning of the cortex and osteosclerosis. However, related chest wall pain is less frequent and is generally mild if present

Inverse problem of estimating transient heat transfer rate on external wall of forced convection pipe

International Nuclear Information System (INIS)

Chen, W.-L.; Yang, Y.-C.; Chang, W.-J.; Lee, H.-L.

2008-01-01

In this study, a conjugate gradient method based inverse algorithm is applied to estimate the unknown space and time dependent heat transfer rate on the external wall of a pipe system using temperature measurements. It is assumed that no prior information is available on the functional form of the unknown heat transfer rate; hence, the procedure is classified as function estimation in the inverse calculation. The accuracy of the inverse analysis is examined by using simulated exact and inexact temperature measurements. Results show that an excellent estimation of the space and time dependent heat transfer rate can be obtained for the test case considered in this study

Controlled Topological Transitions in Thin-Film Phase Separation

KAUST Repository

Hennessy, Matthew G.; Burlakov, Victor M.; Goriely, Alain; Wagner, Barbara; Mü nch, Andreas

2015-01-01

© 2015 Society for Industrial and Applied Mathematics. In this paper the evolution of a binary mixture in a thin-film geometry with a wall at the top and bottom is considered. By bringing the mixture into its miscibility gap so that no spinodal decomposition occurs in the bulk, a slight energetic bias of the walls toward each one of the constituents ensures the nucleation of thin boundary layers that grow until the constituents have moved into one of the two layers. These layers are separated by an interfacial region where the composition changes rapidly. Conditions that ensure the separation into two layers with a thin interfacial region are investigated based on a phase-field model. Using matched asymptotic expansions a corresponding sharp-interface problem for the location of the interface is established. It is then argued that this newly created two-layer system is not at its energetic minimum but destabilizes into a controlled self-replicating pattern of trapezoidal vertical stripes by minimizing the interfacial energy between the phases while conserving their area. A quantitative analysis of this mechanism is carried out via a thin-film model for the free interfaces, which is derived asymptotically from the sharp-interface model.

Review of techniques and detectors used in instruments for field measurement of beta doses and dose rates

International Nuclear Information System (INIS)

Jones, A.R.

1983-01-01

Generally, field measurements are required to assess the hazard from #betta#-rays before personnel are allowed to occupy a working space or perform a task. Occasionally, the measurements are required for an assessment after a #betta#-ray exposure is suspected to have occurred. Until recently the dose or dose rate have been the quantities of interest but there is now felt to be a need to characterize the energies and directions of the #betta#-rays as well. The purpose of #betta#-dosimetry is the assessment of hazard to superficial tissues (within approx. 10 mm of the surface) and that these tissues may also be exposed simultaneously to other ionizing radiations. The #betta#-dosimetry technique must take account of this. With these uses of field instruments in mind the following detectors, and associated techniques will be discussed in terms of the measurement principles, advantages and limitations: thin-walled ion chambers (sometimes in combination with thick-walled ones or with covers thick enough to prevent penetration of #betta#-particles); thin scintillators, nearly tissue equivalent, to provide a detector analogous to skin; scintillators, thick enough to absorb all the energy of the #betta#-particles (circuitry is required to count pulses according to size to permit calculation of dose or dose rate); silicon diodes with thin detection layers operated as photocurrent generators; silicon diodes, reversed biassed, with pulses counted according to size; and simple pulse counters (e.g., GM counters or silicon diodes with thin windows)

Room temperature elastic--plastic response of thin-walled tubes subjected to nonradial combinations of axial and torsional loadings

International Nuclear Information System (INIS)

Liu, K.C.

1975-01-01

Two tubular specimens of type 304 stainless steel with uniform thin walls were subjected to a program of segmental combined tension/compression and torsion loadings at room temperature. A proportional, or radial, loading into the plastic range was initially applied to each specimen. Two nonproportional (nonradial) loadings along straight line segments for which neither the loading paths nor their linear extrapolations passed through the origin of the stress space were then applied. The axial and torsional stress-strain curves for these segmental prestress loadings were plotted. Hence, the stress-strain response characteristics for nonproportional loadings as well as for proportional loading can be studied. In addition, the axial and torsional plastic strain components were calculated, and the total plastic strain trajectories were plotted in a plastic strain space. Finally, using results from a detailed study of yield surfaces, which was performed for the first specimen, a spectrum of initial and subsequent yield curves corresponding to the segmental prestress loadings is presented. (U.S.)

MODELING OF KINEMATICS OF A PLASTIC SHAPING AT CALIBRATION OF A THIN-WALLED PRECISION PIPE SINKING

Directory of Open Access Journals (Sweden)

E. D. Chertov

2014-01-01

Full Text Available Summary. The mathematical model of kinematics of a plastic shaping at the sinking of a thin-walled precision pipe applied to calibration of the ends of the unified elements of the pipeline of aircraft from titanic alloys and corrosion-resistant steel before assembly to the route by means of automatic argon-arc welding of ring joints is developed. For modeling, the power criterion of stability with use of kinematic possible fields of speeds is applied to receiving the top assessment of effort of deformation. The developed model of kinematics of a plastic current allows to receive power parameters of the main condition of process of calibration by sinking and can be used for the solution of a task on stability of process of deformation by results of comparison of power (power parameters for the main (steady and indignant states. Modeling is made in cylindrical system of coordinates by comparison of options of kinematic possible fields of the speeds of a current meeting a condition of incompressibility and kinematic regional conditions. The result of the modeling was selected discontinuous field of high-speed, in which the decrease outer radius (R occurs only by increasing the thickness of the pipe wall (t. For this option the size of pressure of sinking had the smallest value, therefore the chosen field of speeds closely to the valid. It is established that with increase in a step of giving 1 at calibration by the multisector tool the demanded pressure of sinking of q decreases. At an identical step of giving 1 pipe with the smaller relative thickness of (t/r needs to be calibrated the smaller pressure of sinking. With increase of a limit of fluidity at shift of material of pipe preparation pressure of sinking of (q increases.

Pulsed laser deposition of SrRuO3 thin-films: The role of the pulse repetition rate

Directory of Open Access Journals (Sweden)

H. Schraknepper

2016-12-01

Full Text Available SrRuO3 thin-films were deposited with different pulse repetition rates, fdep, epitaxially on vicinal SrTiO3 substrates by means of pulsed laser deposition. The measurement of several physical properties (e.g., composition by means of X-ray photoelectron spectroscopy, the out-of-plane lattice parameter, the electric conductivity, and the Curie temperature consistently reveals that an increase in laser repetition rate results in an increase in ruthenium deficiency in the films. By the same token, it is shown that when using low repetition rates, approaching a nearly stoichiometric cation ratio in SrRuO3 becomes feasible. Based on these results, we propose a mechanism to explain the widely observed Ru deficiency of SrRuO3 thin-films. Our findings demand these theoretical considerations to be based on kinetic rather than widely employed thermodynamic arguments.

Evaluation of Tracheal and Main Bronchial Diverticula Using Thin-Section MDCT

Energy Technology Data Exchange (ETDEWEB)

Jou, Sung Shick; Kim, Young Tong; Bae, Won Kyung; Kim, Il Yung; Kim, Hyung Hwan; Han, Jong Kyu [Soonchunhyang University Cheonan Hospital, Cheonan (Korea, Republic of)

2010-02-15

To evaluate the characteristics of tracheal and main bronchial diverticula in relation with emphysema. A total of 967 CT images were reconstructed with 1.25 mm axial images over 2 months. The incidence, size, number, and location of the tracheal and main bronchial diverticula were analyzed using 3D medical software (Seoul, Korea). The incidence of emphysema and the relationship between emphysema and the size of the diverticula were analyzed. In total, 50 patients (5.1%) showed tracheal diverticula in the right posterolateral wall. In addition, 51 patients (5.2%) showed 89 (9.4%) main bronchial diverticula in the inferior wall, while 68 (72%) showed diverticula in the left posterolateral wall. Tracheal diverticula (6.4 {+-} 5.0 mm, 1.0 {+-} 0.2) were larger and fewer than the main bronchial diverticula (2.1 {+-} 2.0 mm, 1.8 {+-} 1.6) (p<0.05). Moreover, tracheal diverticula (10.3 {+-} 7.4 mm) with emphysema in 13 patients (26%), were larger than those without emphysema (5.1 {+-} 3.0 mm) (p<0.05). On thin-section MDCT, the rates of incidence for tracheal and main bronchial diverticula are about 5%, respectively. Tracheal diverticula in the right posterolateral wall are smaller and fewer than the main bronchial diverticula, which are located primarily in the inferior wall of the left bronchus. Tracheal diverticula with emphysema are larger than those without emphysema.

Effect of the resistive wall on the growth rate of weakly unstable external kink mode in general 3D configurations

International Nuclear Information System (INIS)

Chu, M.S.; Ichiguchi, K.

2005-05-01

Formation of a method for the systematic computation of the growth rate of the weakly unstable RWM in 3D configurations by using results from ideal stability codes is presented. It is shown that the growth rate of the RWM is approximately given by the rate at which the available free energy for the ideal external kink mode can be dissipated by the resistive wall. The eigenfunction is also approximated by that of the external kink mode. This formulation is demonstrated by coupling to the ideal MHD code KSTEP with computation of the dissipation on the resistive wall. Results of the stability of the RWM in LHD plasmas and discussion on the validity and improvement to the computation are also included. (author)

Vibration improved the fluidity of aluminum alloys in thin wall ...

African Journals Online (AJOL)

user

The technique to "increase" the metal head during casting and improve the ... The effect of vibration is quantified and incorporated into the fluidity model, such that the ..... Deformation, caused by the expansion and contraction of the thin skin of ...

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

Science.gov (United States)

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.

An analytical model for shape memory alloy fiber-reinforced composite thin-walled beam undergoing large deflection

Directory of Open Access Journals (Sweden)

Yongsheng Ren

2015-03-01

Full Text Available The structural model of the thin-walled laminated beams with integral shape memory alloy active fibers and accounting for geometrically nonlinear is presented in this article. The structural modeling is split into two parts: a two-dimensional analysis over the cross section and a geometrically nonlinear analysis of a beam along the beam span. The variational asymptotic method is used to formulate the force–deformation relationship equations taking into account the presence of active shape memory alloy fibers distributed along the cross section of the beam. The geometrically nonlinear governing equations are derived using variational principle and based on the von Kármán-type nonlinear strain–displacement relations. The equations are then solved using Galerkin’s method and an incremental Newton–Raphson method. The validation for the proposed model has been carried out by comparison of the present results with those available in the literature. The results show that significant extension, bending, and twisting coupled nonlinear deflections occur during the phase transformation due to shape memory alloy actuation. The effects of the volume fraction of the shape memory alloy fiber and ply angle are also addressed.

Estimates of the burst reliability of thin-walled cylinders designed to meet the ASME Code allowables

International Nuclear Information System (INIS)

Stancampiano, P.A.; Zemanick, P.P.

1976-01-01

Pressure containment components in nuclear power plants are designed by the conventional deterministic safety factor approach to meet the requirements of the ASME Pressure Vessel Code, Section III. The inevitable variabilities and uncertainties associated with the design, manufacture, installation, and service processes suggest a probabilistic design approach may also be pertinent. Accordingly, the burst reliabilities of two thin-walled 304 SS cylindrical vessels such as might be employed in liquid metal plants are estimated. A large vessel fabricated from rolled plate per ASME SA-240 and a smaller pipe sized vessel also fabricated from rolled plate per ASME SA-358 are considered. The vessels are sized to just meet the allowable ASME Code primary membrance stresses at 800 0 F (427 0 C). The bursting probability that the operating pressure is greater than the burst strength of the cylinders is calculated using stress-strength interference theory by direct Monte Carlo simulation on a high speed digital computer. A sensitivity study is employed to identify those design parameters which have the greatest effect on the reliability. The effects of preservice quality assurance defect inspections on the reliability are also evaluated parametrically

Growth and Etch Rate Study of Low Temperature Anodic Silicon Dioxide Thin Films

Directory of Open Access Journals (Sweden)

Akarapu Ashok

2014-01-01

Full Text Available Silicon dioxide (SiO2 thin films are most commonly used insulating films in the fabrication of silicon-based integrated circuits (ICs and microelectromechanical systems (MEMS. Several techniques with different processing environments have been investigated to deposit silicon dioxide films at temperatures down to room temperature. Anodic oxidation of silicon is one of the low temperature processes to grow oxide films even below room temperature. In the present work, uniform silicon dioxide thin films are grown at room temperature by using anodic oxidation technique. Oxide films are synthesized in potentiostatic and potentiodynamic regimes at large applied voltages in order to investigate the effect of voltage, mechanical stirring of electrolyte, current density and the water percentage on growth rate, and the different properties of as-grown oxide films. Ellipsometry, FTIR, and SEM are employed to investigate various properties of the oxide films. A 5.25 Å/V growth rate is achieved in potentiostatic mode. In the case of potentiodynamic mode, 160 nm thickness is attained at 300 V. The oxide films developed in both modes are slightly silicon rich, uniform, and less porous. The present study is intended to inspect various properties which are considered for applications in MEMS and Microelectronics.

Numerical analysis for the optimal location of a thin PCM layer in frame walls

International Nuclear Information System (INIS)

Jin, Xing; Medina, Mario A.; Zhang, Xiaosong

2016-01-01

Highlights: • The optimal PCM location was estimated by a mathematical model. • The optimal PCM location was affected by the properties of PCM. • The optimal PCM location was affected by the environmental conditions. - Abstract: The thermal performance of building walls can be improved using phase change materials (PCMs). The objective of this study was to estimate the optimal location of a “thin” PCM layer to be incorporated into frame walls, parallel to the frame and insulation, for the purpose of increasing thermal mass and reducing peak heat fluxes through the wall. Based on a mathematical model built in this paper, it was found that an optimal location of this “thin” PCM layer can be estimated, and it was affected by the thermal properties of PCM and the environmental conditions. The optimal locations for the PCM layer were found to be closer to the exterior surface of the wall when the thickness of PCM layer, the heat of fusion of PCM, and the PCM melting temperature were increased, while the optimal location was closer to the interior surface of the wall when the interior surface temperature of the wall was increased.

The Rayleigh law in silicon doped hafnium oxide ferroelectric thin films

Energy Technology Data Exchange (ETDEWEB)

Guan, Yan; Liu, Xiaohua [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian (China); Zhou, Dayu [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian (China); State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu (China); Xu, Jin [Department of Electronic Engineering, Dalian Neusoft University of Information, Dalian (China); Cao, Fei; Dong, Xianlin [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China); Mueller, Johannes [Fraunhofer IPMS-CNT, Dresden (Germany); Schenk, Tony; Schroeder, Uwe [NaMLab gGmbH/TU Dresden (Germany)

2015-10-15

A wealth of studies have confirmed that the low-field hysteresis behaviour of ferroelectric bulk ceramics and thin films can be described using Rayleigh relations, and irreversible domain wall motion across the array of pining defects has been commonly accepted as the underlying micro-mechanism. Recently, HfO{sub 2} thin films incorporated with various dopants were reported to show pronounced ferroelectricity, however, their microscopic domain structure remains unclear till now. In this work, the effects of the applied electric field amplitude, frequency and temperature on the sub-coercive polarization reversal properties were investigated for 10 nm thick Si-doped HfO{sub 2} thin films. The applicability of the Rayleigh law to ultra-thin ferroelectric films was first confirmed, indicating the existence of a multi-domain structure. Since the grain size is about 20-30 nm, a direct observation of domain walls within the grains is rather challenging and this indirect method is a feasible approach to resolve the domain structure. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The Rayleigh law in silicon doped hafnium oxide ferroelectric thin films

International Nuclear Information System (INIS)

Guan, Yan; Liu, Xiaohua; Zhou, Dayu; Xu, Jin; Cao, Fei; Dong, Xianlin; Mueller, Johannes; Schenk, Tony; Schroeder, Uwe

2015-01-01

A wealth of studies have confirmed that the low-field hysteresis behaviour of ferroelectric bulk ceramics and thin films can be described using Rayleigh relations, and irreversible domain wall motion across the array of pining defects has been commonly accepted as the underlying micro-mechanism. Recently, HfO 2 thin films incorporated with various dopants were reported to show pronounced ferroelectricity, however, their microscopic domain structure remains unclear till now. In this work, the effects of the applied electric field amplitude, frequency and temperature on the sub-coercive polarization reversal properties were investigated for 10 nm thick Si-doped HfO 2 thin films. The applicability of the Rayleigh law to ultra-thin ferroelectric films was first confirmed, indicating the existence of a multi-domain structure. Since the grain size is about 20-30 nm, a direct observation of domain walls within the grains is rather challenging and this indirect method is a feasible approach to resolve the domain structure. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Durability of thin-walled concrete structures

International Nuclear Information System (INIS)

Salomon, M.; Gallias, J.L.

1991-01-01

The aim of the present document is to draw up a survey of knowledge of the problems of ageing of reinforced concrete shell structure atmospheric coolers. The exposure conditions are particularly favourable to the induction and development of degradation which, because of the thinness of the reinforced concrete can compromise the stability and the durability of coolers. The study will be axed on the link between the specific characteristics of coolers from the point of view of operation, design and environment, also the durability of reinforced concrete. The set of factors exerting their influence on the reinforced concrete of the shell structure (condensates, rain water, temperature and humidity gradients, dynamic loads, weathering, etc.) is particularly complex. The principal degradation reactions involved are classified according to the chemical and physical action on concrete and on the reinforcement. Particular emphasis is placed on the analysis of degradation processes and the influence of the characteristics of the materials and of the medium. The aim is to determine the mechanisms which present the greatest risk for coolers. The interaction between the degradation to concrete and the change in mechanical characteristics is also studied [fr

Rib fracture after stereotactic radiotherapy on follow-up thin-section computed tomography in 177 primary lung cancer patients

Directory of Open Access Journals (Sweden)

Saito Ryo

2011-10-01

Full Text Available Abstract Background Chest wall injury after stereotactic radiotherapy (SRT for primary lung cancer has recently been reported. However, its detailed imaging findings are not clarified. So this study aimed to fully characterize the findings on computed tomography (CT, appearance time and frequency of chest wall injury after stereotactic radiotherapy (SRT for primary lung cancer Materials and methods A total of 177 patients who had undergone SRT were prospectively evaluated for periodical follow-up thin-section CT with special attention to chest wall injury. The time at which CT findings of chest wall injury appeared was assessed. Related clinical symptoms were also evaluated. Results Rib fracture was identified on follow-up CT in 41 patients (23.2%. Rib fractures appeared at a mean of 21.2 months after the completion of SRT (range, 4 -58 months. Chest wall edema, thinning of the cortex and osteosclerosis were findings frequently associated with, and tending to precede rib fractures. No patients with rib fracture showed tumors > 16 mm from the adjacent chest wall. Chest wall pain was seen in 18 of 177 patients (10.2%, of whom 14 patients developed rib fracture. No patients complained of Grade 3 or more symptoms. Conclusion Rib fracture is frequently seen after SRT for lung cancer on CT, and is often associated with chest wall edema, thinning of the cortex and osteosclerosis. However, related chest wall pain is less frequent and is generally mild if present.

Rib fracture after stereotactic radiotherapy on follow-up thin-section computed tomography in 177 primary lung cancer patients

Science.gov (United States)

2011-01-01

Background Chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer has recently been reported. However, its detailed imaging findings are not clarified. So this study aimed to fully characterize the findings on computed tomography (CT), appearance time and frequency of chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer Materials and methods A total of 177 patients who had undergone SRT were prospectively evaluated for periodical follow-up thin-section CT with special attention to chest wall injury. The time at which CT findings of chest wall injury appeared was assessed. Related clinical symptoms were also evaluated. Results Rib fracture was identified on follow-up CT in 41 patients (23.2%). Rib fractures appeared at a mean of 21.2 months after the completion of SRT (range, 4 -58 months). Chest wall edema, thinning of the cortex and osteosclerosis were findings frequently associated with, and tending to precede rib fractures. No patients with rib fracture showed tumors > 16 mm from the adjacent chest wall. Chest wall pain was seen in 18 of 177 patients (10.2%), of whom 14 patients developed rib fracture. No patients complained of Grade 3 or more symptoms. Conclusion Rib fracture is frequently seen after SRT for lung cancer on CT, and is often associated with chest wall edema, thinning of the cortex and osteosclerosis. However, related chest wall pain is less frequent and is generally mild if present. PMID:21995807

Highly coercive thin-film nanostructures

International Nuclear Information System (INIS)

Zhou, J.; Skomski, R.; Kashyap, A.; Sorge, K.D.; Sui, Y.; Daniil, M.; Gao, L.; Yan, M.L.; Liou, S.-H.; Kirby, R.D.; Sellmyer, D.J.

2005-01-01

The processing, structure, and magnetism of highly coercive Sm-Co and FePt thin-film nanostructures are investigated. The structures include 1:5 based Sm-Co-Cu-Ti magnets, particulate FePt:C thin films, and FePt nanotubes. As in other systems, the coercivity depends on texture and imperfections, but there are some additional features. A specific coercivity mechanism in particulate media is a discrete pinning mode intermediate between Stoner-Wohlfarth rotation and ordinary domain-wall pinning. This mechanism yields a coercivity maximum for intermediate intergranular exchange and explains the occurrence of coercivities of 5 T in particulate Sm-Co-Cu-Ti magnets

Effect of injection parameters on mechanical and physical properties of super ultra-thin wall propylene packaging by Taguchi method

Science.gov (United States)

Ginghtong, Thatchanok; Nakpathomkun, Natthapon; Pechyen, Chiravoot

2018-06-01

The parameters of the plastic injection molding process have been investigated for the manufacture of a 64 oz. ultra-thin polypropylene bucket. The 3 main parameters, such as injection speed, melting temperature, holding pressure, were investigated to study their effect on the physical appearance and compressive strength. The orthogonal array of Taguchi's L9 (33) was used to carry out the experimental plan. The physical properties were measured and the compressive strength was determined using linear regression analysis. The differential scanning calorimeter (DSC) was used to analyze the crystalline structure of the product. The optimization results show that the proposed approach can help engineers identify optimal process parameters and achieve competitive advantages of energy consumption and product quality. In addition, the injection molding of the product includes 24 mm of shot stroke, 1.47 mm position transfer, 268 rpm screw speed, injection speed 100 mm/s, 172 ton clamping force, 800 kgf holding pressure, 0.9 s holding time and 1.4 s cooling time, make the products in the shape and proportion of the product satisfactory. The parameters of influence are injection speed 71.07%, melting temperature 23.31% and holding pressure 5.62%, respectively. The compressive strength of the product was able to withstand a pressure of up to 839 N before the product became plastic. The low melting temperature was caused by the superior crystalline structure of the super-ultra-thin wall product which leads to a lower compressive strength.

Near-net-shape 95W-3.5Ni-1.5Fe thin-walled products produced by plasma spray forming

International Nuclear Information System (INIS)

Wang, Y.M.; Xiong, X.; Min, X.B.; Xie, L.; Zheng, F.

2010-01-01

Tungsten heavy alloy 95W-3.5Ni-1.5Fe (in wt.%) refractory metallic thin-walled products (diameter ≤100 mm, length ≤150 mm and wall thickness ≤5 mm) were produced using plasma spray forming (PSF) covered in argon atmosphere at a pressure of 1.01 x 10 5 Pa followed by vacuum liquid phase sintering at 1465, 1485 and 1500 deg. C for 90 min, respectively. A lamellar structure consisting of vertical columnar grains and some fine particles was found in PSF deposits. Relative density of the deposits was about 87.70% with poor mechanical property. Upon vacuum liquid phase sintering, their density and property have been improved significantly. The microstructures of PSF deposits before and after vacuum sintering were found to consist with tungsten and (Ni, Fe)-rich phase. Volume fraction of (Ni, Fe)-rich phase was decreased due to vaporization that occurred in plasma spraying and vacuum liquid phase sintering. Their fracture surfaces were dominated by intergranular rupture. The lamellar structure remained in the deposits during early stages of sintering (solid state sintering and initial of liquid phase sintering). Particle rearrangement and rapid densification of the deposits did not occur until the surface of tungsten particles being modified and changed into spheroids by solution and precipitation. In the end, the PSF deposits have been transformed from lamellar structure into two phase composites with dispersed spheroidal tungsten grains embedded in a continuous network of (Ni, Fe)-rich phase.

Screen printing as a scalable and low-cost approach for rigid and flexible thin-film transistors using separated carbon nanotubes.

Science.gov (United States)

Cao, Xuan; Chen, Haitian; Gu, Xiaofei; Liu, Bilu; Wang, Wenli; Cao, Yu; Wu, Fanqi; Zhou, Chongwu

2014-12-23

Semiconducting single-wall carbon nanotubes are very promising materials in printed electronics due to their excellent mechanical and electrical property, outstanding printability, and great potential for flexible electronics. Nonetheless, developing scalable and low-cost approaches for manufacturing fully printed high-performance single-wall carbon nanotube thin-film transistors remains a major challenge. Here we report that screen printing, which is a simple, scalable, and cost-effective technique, can be used to produce both rigid and flexible thin-film transistors using separated single-wall carbon nanotubes. Our fully printed top-gated nanotube thin-film transistors on rigid and flexible substrates exhibit decent performance, with mobility up to 7.67 cm2 V(-1) s(-1), on/off ratio of 10(4)∼10(5), minimal hysteresis, and low operation voltage (transistors (bent with radius of curvature down to 3 mm) and driving capability for organic light-emitting diode have been demonstrated. Given the high performance of the fully screen-printed single-wall carbon nanotube thin-film transistors, we believe screen printing stands as a low-cost, scalable, and reliable approach to manufacture high-performance nanotube thin-film transistors for application in display electronics. Moreover, this technique may be used to fabricate thin-film transistors based on other materials for large-area flexible macroelectronics, and low-cost display electronics.

Wall-slip effects in SnAgCu solder pastes used in electronics assembly applications

International Nuclear Information System (INIS)

Mallik, S.; Ekere, N.N.; Durairaj, R.; Marks, A.E.; Seman, A.

2009-01-01

Solder paste is the most important strategic bonding material used in the assembly of surface mount components in electronics manufacturing. As the trend towards miniaturisation of electronic products continues, there is an increasing demand for better understanding of the flow and deformation that is, the rheological behaviour of solder paste formulations. Wall slip plays an important role in characterising the flow behaviour of solder paste materials. The problem of wall slip arises due to the various attractive and repulsive forces acting between the solder particles and the walls of the measuring geometry. These interactions could lead to the presence of a thin solvent layer adjacent to the wall, which gives rise to slippage. In rheological measurements, slip effects can generally be avoided by using roughened surfaces for measuring geometries. In this paper, a novel technique is developed to study the effect of wall slip in the rheological measurements of lead-free solder paste. The viscosity and oscillatory data obtained for three different solder paste samples (from measuring geometries of different surface roughness) have been analysed and compared. In viscosity measurements, slip effects were dominant at low shear rates and the use of serrated surfaces was found to be quite effective in minimizing slip effects. Oscillatory measurements were also affected by roughening the surfaces of measuring geometries.

Interaction of initial litter quality and thinning intensity on litter decomposition rate, nitrogen accumulation and release in a pine plantation

Science.gov (United States)

Xiao Chen; Deborah Page-Dumroese; Ruiheng Lv; Weiwei Wang; Guolei Li; Yong. Liu

2014-01-01

Thinning alters litter quality and microclimate under forests. Both of these two changes after thinning induce alterations of litter decomposition rates and nutrient cycling. However, a possible interaction between these two changes remains unclear. We placed two types of litter (LN, low N concentration litter; HN, high N concentration litter) in a Chinese pine (Pinus...

Near wall combustion modeling in spark ignition engines. Part A: Flame–wall interaction

International Nuclear Information System (INIS)

Demesoukas, Sokratis; Caillol, Christian; Higelin, Pascal; Boiarciuc, Andrei; Floch, Alain

2015-01-01

Highlights: • A model for flame–wall interaction in addition to flame wrinkling by turbulence is proposed. • Two sparkplug positions and two lengths are used in a test engine for model validation. • Flame–wall interaction decreases the maximum values of cylinder pressure and heat release rates. • The impact of combustion chamber geometry is taken into account by the flame–wall interaction model. - Abstract: Research and design in the field of spark ignition engines seek to achieve high performance while conserving fuel economy and low pollutant emissions. For the evaluation of various engine configurations, numerical simulations are favored, since they are quick and less expensive than experiments. Various zero-dimensional combustion models are currently used. Both flame front reactions and post-flame processes contribute to the heat release rate. The first part of this study focuses on the role of the flame front on the heat release rate, by modeling the interaction of the flame front with the chamber wall. Post-flame reactions are dealt with in Part B of the study. The basic configurations of flame quenching in laminar flames are also applicable in turbulent flames, which is the case in spark ignition engines. A simplified geometric model of the combustion chamber was used to calculate the mean flame surface, the flame volume and the distribution of flame surface as a function of the distance from the wall. The flame–wall interaction took into account the geometry of the combustion chamber and of the flame, aerodynamic turbulence and the in-cylinder pressure and temperature conditions, through a phenomenological attenuation function of the wrinkling factor. A modified global wrinkling factor as a function of the mean surface distance distribution from the wall was calculated. The impact of flame–wall interaction was simulated for four configurations of the sparkplug position and length: centered and lateral position, and standard and projected

Reynolds number calculation and applications for curved wall jets

Directory of Open Access Journals (Sweden)

Valeriu DRAGAN

2014-09-01

Full Text Available The current paper refers to the preliminary estimation of the Reynolds number for curved wall jets. This, in turn, can be a useful tool for controlling the boundary layer mesh size near a generic curved wall which is wetted by a thin, attached jet. The method relies on analytical calculations that link the local curvature of the wall with the pressure gradient and further, the local Reynolds number. Knowing the local Reynolds number distribution, a CFD user can tailor their mesh size to more exact specifications (e.g. y+=1 for k-omega RANS models and lower the risk that the mesh is too coarse or finer than necessary.

Effects of argon flow rate on electrical properties of amorphous indium gallium zinc oxide thin-film transistors

Energy Technology Data Exchange (ETDEWEB)

Sahoo, A.K.; Wu, G.M., E-mail: wu@mail.cgu.edu.tw

2016-04-30

In this report, amorphous indium gallium zinc oxide (a-IGZO) thin films were deposited on glass substrates using different argon flow rates (AFRs). The impact on the electrical properties of the a-IGZO thin-film transistors with various AFRs during film growth has been carefully investigated. The AFR varied 20–60 sccm while the oxygen flow rate was maintained at 1 sccm. All a-IGZO films achieved transmittance higher than 80% in the wavelength range of 350–1000 nm, and it increased slightly with increasing AFR in the higher wavelength region. The rise in partial pressure due to increased AFR could affect the performance, in particular by increasing the current on/off ratio, and changes in electron mobility, sub-threshold swing voltage and threshold voltage. The optimal results were attained at AFR of 50 sccm. The field effect mobility, sub-threshold swing, ratio of on-current to the off-current, interfacial trap density and threshold voltage are 27.7 cm{sup 2}/V·s, 0.11 V/dec, 2.9 × 10{sup 8}, 1.1 × 10{sup 12} cm{sup −2} eV{sup −1} and 0.84 V, respectively. In addition, good electrical properties were achieved using dielectric SiO{sub 2} prepared by simple, low-cost electron beam evaporator system. - Highlights: • IGZO thin films RF-sputtered on glass substrates under various Ar to oxygen flow rates • The electrical performances and thin film quality of a-IGZO TFT were characterized. • High mobility 27.7 cm{sup 2}/V·s and very small sub-threshold voltage 0.11 V/decade obtained. • Simple and low cost electron-beam deposited SiO{sub 2} used as gate dielectric. • Ohmic behavior of source–drain with channel material has been achieved.

Effects of argon flow rate on electrical properties of amorphous indium gallium zinc oxide thin-film transistors

International Nuclear Information System (INIS)

Sahoo, A.K.; Wu, G.M.

2016-01-01

In this report, amorphous indium gallium zinc oxide (a-IGZO) thin films were deposited on glass substrates using different argon flow rates (AFRs). The impact on the electrical properties of the a-IGZO thin-film transistors with various AFRs during film growth has been carefully investigated. The AFR varied 20–60 sccm while the oxygen flow rate was maintained at 1 sccm. All a-IGZO films achieved transmittance higher than 80% in the wavelength range of 350–1000 nm, and it increased slightly with increasing AFR in the higher wavelength region. The rise in partial pressure due to increased AFR could affect the performance, in particular by increasing the current on/off ratio, and changes in electron mobility, sub-threshold swing voltage and threshold voltage. The optimal results were attained at AFR of 50 sccm. The field effect mobility, sub-threshold swing, ratio of on-current to the off-current, interfacial trap density and threshold voltage are 27.7 cm"2/V·s, 0.11 V/dec, 2.9 × 10"8, 1.1 × 10"1"2 cm"−"2 eV"−"1 and 0.84 V, respectively. In addition, good electrical properties were achieved using dielectric SiO_2 prepared by simple, low-cost electron beam evaporator system. - Highlights: • IGZO thin films RF-sputtered on glass substrates under various Ar to oxygen flow rates • The electrical performances and thin film quality of a-IGZO TFT were characterized. • High mobility 27.7 cm"2/V·s and very small sub-threshold voltage 0.11 V/decade obtained. • Simple and low cost electron-beam deposited SiO_2 used as gate dielectric. • Ohmic behavior of source–drain with channel material has been achieved.

Plasma deposition of thin film silicon at low substrate temperature and at high growth rate

NARCIS (Netherlands)

Verkerk, A.D.|info:eu-repo/dai/nl/304831719

2009-01-01

To expand the range of applications for thin film solar cells incorporating hydrogenated amorphous silicon (a-Si:H) and hydrogenated nanocrystalline silicon (nc-Si:H), the growth rate has to be increased 0.5 or less to several nm/s and the substrate temperature should be lowered to around 100 C. In

Screening method for piping wall loss by flow accelerated corrosion

International Nuclear Information System (INIS)

Ryu, Kyung Ha; Hwang, Il Soon; Lee, Na Young; Oh, Young Jin; Kim, Ji Hyun; Park, Jin Ho; Sohn, Chang Ho

2008-01-01

Flow accelerated corrosion (FAC) phenomenon has persisted its impact on plant reliability and personnel safety. Unless we change the operation condition drastically, most parameters affecting FAC will not be effectively controlled. In order to help expand piping inspection coverage, we have developed a screening approach to monitor the wall thinning by direct current potential drop (DCPD) technique. To improve the applicability to the complex piping network such as the secondary cooling water system in PWR's, we devised the equipotential control method that can eliminate undesired leakage currents outside a measurement section. In this paper, we present Wide Range Monitoring (WiRM) and Narrow Range Monitoring (NaRM) with Equipotential Switching Direct Current Potential Drop (ES-DCPD) method to rapidly monitor the thinning of piping. Based on the WiRM results, susceptible locations can be identified for further inspection by ultrasound technique (UT). On-line monitoring of a thinned location can be made by NaRM. Finite element analysis results and a closed-form resistance model are developed for the comparison with measured wall thinning by the developed DCPD technique. Verification experiments were conducted using UT as the reference. The result shows that model predictions and the experimental results agree well to confirm that both WiRM and NaRM based on ES-DCPD can be applicable to FAC management efforts

Screening method for piping wall loss by flow accelerated corrosion

International Nuclear Information System (INIS)

Ryu, K.H.; Hwang, I.S.; Lee, N.Y.; Oh, Y.J.; Park, J.H.; Sohn, C.H.

2007-01-01

Flow accelerated corrosion (FAC) phenomenon has persisted in its impact on plant reliability and personnel safety. Unless we change the operation condition drastically, most parameters affecting FAC will not be effectively controlled. In order to help expand piping inspection coverage, we have developed a screening approach to monitor the wall thinning by a Direct Current Potential drop (DCPD) technique. To improve the applicability to the complex piping network such as the secondary cooling water system in PWR's, we devised the equipotential control method that can eliminate undesired leakage currents outside a measurement section. In this paper, we present Wide Range Monitoring (WiRM) and Narrow Range Monitoring (NaRM) with Equipotential Switching Direct Current Potential Drop (ES-DCPD) method to rapidly monitor the thinning of piping. Based on the WiRM results, susceptible locations can be identified for further inspection by Ultrasonic Technique (UT). On-line monitoring of a thinned location can be made by NaRM. Finite element analysis results and a closed-form resistance model are developed for the comparison with measured wall thinning by the developed DCPD technique. Verification experiments were conducted using UT as the reference. The result shows that model predictions and the experimental results agree well to confirm that both WiRM and NaRM based on ES-DCPD can be applicable to FAC management efforts. (author)

Post-operative cyst and orbital walls. A CT image analysis

Energy Technology Data Exchange (ETDEWEB)

Fukuta, Masahiro (Takeda General Hospital, Aizuwakamatsu, Fukushima (Japan)); Iinuma, Toshitaka

1989-07-01

A set of coronal CT images obtained by 118 sides (109 cases) of post-operative cysts of maxilla, seen from 1982 to 1988, was analyzed as to the orbital wall affections. Coronal images were grouped into five consecutive planes, i.e. the first plane being the one which is 5 mm posterior to the nasion, and the other planes in successive orders each being 5 mm apart. The orbital walls were classified into inferior, medial, and transition of these two. The orbital wall affections were classified into dehiscence, thinned-out (less than 1 mm), and normal. The orbital signs and symptoms (epiphora, pain, asthenopia, visual loss, diplopia, and exophthalmos) were analyzed based upon the questionnaires by patients. The inferior wall affections (dehiscence and thinned-out) were seen most often (57%) at the third plane (2 cm posterior to the nasion). The orbital signs and symptoms in general were seen in half of the cases of which 20% were of grave (visual loss, diplopia and exophthalmos). These signs and symptoms were the more often, the more anterior the site of affections located. Grave signs and symptoms were seen at 2 to 2.5 cm posterior to the nasion when the orbital floor was affected and the inferior rectus were either pushed up or in direct contact with the cysts. (author).

Controlling growth rate anisotropy for formation of continuous ZnO thin films from seeded substrates

International Nuclear Information System (INIS)

Zhang, R H; Slamovich, E B; Handwerker, C A

2013-01-01

Solution-processed zinc oxide (ZnO) thin films are promising candidates for low-temperature-processable active layers in transparent thin film electronics. In this study, control of growth rate anisotropy using ZnO nanoparticle seeds, capping ions, and pH adjustment leads to a low-temperature (90 ° C) hydrothermal process for transparent and high-density ZnO thin films. The common 1D ZnO nanorod array was grown into a 2D continuous polycrystalline film using a short-time pure solution method. Growth rate anisotropy of ZnO crystals and the film morphology were tuned by varying the chloride (Cl − ) ion concentration and the initial pH of solutions of zinc nitrate and hexamethylenetetramine (HMTA), and the competitive adsorption effects of Cl − ions and HMTA ligands on the anisotropic growth behavior of ZnO crystals were proposed. The lateral growth of nanorods constituting the film was promoted by lowering the solution pH to accelerate the hydrolysis of HMTA, thereby allowing the adsorption effects from Cl − to dominate. By optimizing the growth conditions, a dense ∼100 nm thickness film was fabricated in 15 min from a solution of [Cl − ]/[Zn 2+ ] = 1.5 and pH= 4.8 ± 0.1. This film shows >80% optical transmittance and a field-effect mobility of 2.730 cm 2 V −1 s −1 at zero back-gate bias. (paper)

Giant flux jumps through a thin superconducting Nb film in a vortex free region

International Nuclear Information System (INIS)

Tsindlekht, M.I.; Genkin, V.M.; Felner, I.; Zeides, F.; Katz, N.; Gazi, Š.; Chromik, Š.

2016-01-01

Highlights: Giant magnetic flux jumps into thin-walled cylinder were measured using peak up coil method in a swept magnetic field. Magnetic moment jumps were observed in magnetic fields lower and above Hc1. - Abstract: We measure the dynamics of magnetic field penetration into thin-walled superconducting niobium cylinders. It is shown that magnetic field penetrates through the wall of a cylinder in a series of giant jumps with amplitude 1 - 2 mT and duration of less than a microsecond in a wide range of magnetic fields, including the vortex free region. Surprisingly, the jumps take place when the total current in the wall, not the current density, exceeds a critical value. In addition, there are small jumps and/or smooth penetration, but their contribution reaches only ≃ 20 % of the total penetrating flux. The number of jumps decreases with increased temperature. Thermomagnetic instabilities cannot explain the experimental observations.

Giant flux jumps through a thin superconducting Nb film in a vortex free region

Energy Technology Data Exchange (ETDEWEB)

Tsindlekht, M.I., E-mail: mtsindl@vms.huji.ac.il [The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Genkin, V.M.; Felner, I.; Zeides, F.; Katz, N. [The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Gazi, Š.; Chromik, Š. [The Institute of Electrical Engineering SAS, Dúbravská cesta 9, 84104 Bratislava (Slovakia)

2016-10-15

Highlights: Giant magnetic flux jumps into thin-walled cylinder were measured using peak up coil method in a swept magnetic field. Magnetic moment jumps were observed in magnetic fields lower and above Hc1. - Abstract: We measure the dynamics of magnetic field penetration into thin-walled superconducting niobium cylinders. It is shown that magnetic field penetrates through the wall of a cylinder in a series of giant jumps with amplitude 1 - 2 mT and duration of less than a microsecond in a wide range of magnetic fields, including the vortex free region. Surprisingly, the jumps take place when the total current in the wall, not the current density, exceeds a critical value. In addition, there are small jumps and/or smooth penetration, but their contribution reaches only ≃ 20 % of the total penetrating flux. The number of jumps decreases with increased temperature. Thermomagnetic instabilities cannot explain the experimental observations.

Construction of Earthquake - Proof Safety Evaluaiton Methods for Pipes with Wall Thinning

International Nuclear Information System (INIS)

Miyano, H.; Sekimura, N.; Takizawa, M.; Mastumoto, M.

2012-01-01

Since the Fukushima Dai-ichi accident, the importance of 'system safety' has been recognized anew. Particularly, system safety assessment of plants in operation from the various degradation perspectives, specifically, transition of time is very important. Accordingly, assessment on degradation will focus on the degradation of functions with passing of time, combined with the changes in the safety standards and concept of safety. Reliability assessment will be made on the consolidation of important functions, and not on individual components. The boundary function of the system will be one of the focus of this study. For the purpose of reliability assessment on the system by evaluating and quantifying the damage (or rupture) risk of piping - method for confirming the integrity of the system through the assessment on the damage (rupture) risk of the system when an external force caused by an earthquake is applied (the system is sound if the damage (rupture) risk is small) was examined on the basis of the prediction results for each of the parts in pipe wall thinning. In the next phase, the prediction results will be verified by tests, whereby, the improvement in reliability will be confirmed, and a combined assessment will be made in relation to the degradation factors of other systems. 'System safety' assessment method of plants in operation will be developed in a manner where a comprehensive assessment on the safety of the entire plant can be made. Specifically, the changes in the conditions, such as material degradations that degrade performance will be assessed on the entire system. Whereby, the risk caused by functional failure (damage) due to degradation will be regarded as the total of risk in the assessment. A framework on safety assessment will be structured, where the degree of safety will be measured by functional degradation, taking into consideration the changes made in the safety standards up to present. (author)

Rate constant of free electrons and holes recombination in thin films CdSe

International Nuclear Information System (INIS)

Radychev, N.A.; Novikov, G.F.

2006-01-01

Destruction kinetics of electrons generated in thin films CdSe by laser impulse (wave length is 337 nm, period of impulse - 8 nc) is studied by the method of microwave photoconductivity (36 GHz) at 295 K. Model of the process was suggested using the analysis of kinetics of photo-responses decay, and it allowed determination of rate constant of recombination of free electrons and holes in cadmium selenide - (4-6)x10 -11 cm 3 s -1 [ru

Impact of turbulence anisotropy near walls in room airflow

DEFF Research Database (Denmark)

Schälin, A.; Nielsen, Peter Vilhelm

2004-01-01

The influence of different turbulence models used in computational fluid dynamics predictions is studied in connection with room air movement. The turbulence models used are the high Re-number k–e model and the high Re- number Reynolds stress model (RSM). The three-dimensional wall jet is selected...... in a three- dimensional wall jet by the k–e turbulence model. Furthermore, it is shown that the growth rate can be predicted to a certain extent by the RSM with wall reflection terms. The flow in a deep room can be strongly influenced by details as the growth rate of a three-dimensional wall jet. Predictions...... for the work. The growth rate parallel to the wall in a three-dimensional wall jet is large compared with the growth rate perpendicular to the wall, and it is large compared with the growth rate in a free circular jet. It is shown that it is not possible to predict the high growth rate parallel with a surface...

Detection of thin wall regions of unruptured cerebral aneurysms by ECG synchronous reconstruction 3D-CT angiography (4D-CTA) using 16 slices per rotation CT

International Nuclear Information System (INIS)

Fujita, Shigekiyo

2004-01-01

The objective of this study was to evaluate the capability of electrocardiogram (ECG) synchronous reconstruction 3D-CT angiography (4D-CTA) using 16 sequence MD-CT to detect weak portions of unruptured cerebral aneurysm. 4D-CT angiography of unruptured cerebral aneurysms was performed on 26 patients, 28 cerebral aneurysms, using 16 sequence MD-CT (GE, HiLight Matrix II). Contrast material of iodine (300 mg/ml) was injected over 30 sec period into the ante-cubital vein with a rate of 0.06 ml/Kg/sec. ECG synchronous reconstruction images (10 images at intervals of 10% between R-R of ECG) were generated (GE, Workstation Advantage 4.1). After careful inspection of the wall motion of an aneurysm from many aspects, cine images were made from several directions. Acquisition of data required 9 seconds, total volume data were generated within 15 minutes, and ECG synchronous reconstruction image processing was performed in about 5 minutes. Animation creation for one direction was completed within one minute. Even in 3-mm aneurysms, changes of its form and size within a heartbeat were fully observed. Timing of maximum and minimum sizes were also recognized. The pulsatile changes and nipple extent, bleb, daughter, and dome of aneurysms were well visualized. The projecting motion of the pulsatory enlargement of nipple was detected in nine cases, and definite increases in bleb sizes were detected in five cases. Since the easily reptured thin walled portion of a cerebral aneurysm can be recognized by this method, 4D-CT angiography is likely to become indispensable in judging how to cope with unruptured cerebral aneurysms, in deciding whether to operate or observe. (author)

Material and structural mechanical modelling and reliability of thin-walled bellows at cryogenic temperatures. Application to LHC compensation system

CERN Document Server

Garion, Cédric; Skoczen, Blazej

The present thesis is dedicated to the behaviour of austenitic stainless steels at cryogenic temperatures. The plastic strain induced martensitic transformation and ductile damage are taken into account in an elastic-plastic material modelling. The kinetic law of →’ transformation and the evolution laws of kinematic/isotropic mixed hardening are established. Damage issue is analysed by different ways: mesoscopic isotropic or orthotropic model and a microscopic approach. The material parameters are measured from 316L fine gauge sheet at three levels of temperature: 293 K, 77 K and 4.2 K. The model is applied to thin-walled corrugated shell, used in the LHC interconnections. The influence of the material properties on the stability is studied by a modal analysis. The reliability of the components, defined by the Weibull distribution law, is analysed from fatigue tests. The impact on reliability of geometrical imperfections and thermo-mechanical loads is also analysed.

Dose rate evaluation of body phantom behind ITER bio-shield wall using Monte Carlo method

International Nuclear Information System (INIS)

Beheshti, A.; Jabbari, I.; Karimian, A.; Abdi, M.

2012-01-01

One of the most critical risks to humans in reactors environment is radiation exposure. Around the tokamak hall personnel are exposed to a wide range of particles, including neutrons and photons. International Thermonuclear Experimental Reactor (ITER) is a nuclear fusion research and engineering project, which is the most advanced experimental tokamak nuclear fusion reactor. Dose rates assessment and photon radiation due to the neutron activation of the solid structures in ITER is important from the radiological point of view. Therefore, the dosimetry considered in this case is based on the Deuterium-Tritium (DT) plasma burning with neutrons production rate at 14.1 MeV. The aim of this study is assessment the amount of radiation behind bio-shield wall that a human received during normal operation of ITER by considering neutron activation and delay gammas. To achieve the aim, the ITER system and its components were simulated by Monte Carlo method. Also to increase the accuracy and precision of the absorbed dose assessment a body phantom were considered in the simulation. The results of this research showed that total dose rates level near the outside of bio-shield wall of the tokamak hall is less than ten percent of the annual occupational dose limits during normal operation of ITER and It is possible to learn how long human beings can remain in that environment before the body absorbs dangerous levels of radiation. (authors)

Hysteresis of the Contact Angle of a Meniscus Inside a Capillary with Smooth, Homogeneous Solid Walls.

Science.gov (United States)

Kuchin, Igor V; Starov, Victor M

2016-05-31

A theory of contact angle hysteresis of a meniscus inside thin capillaries with smooth, homogeneous solid walls is developed in terms of surface forces (disjoining/conjoining pressure isotherm) using a quasi-equilibrium approach. The disjoining/conjoining pressure isotherm includes electrostatic, intermolecular, and structural components. The values of the static receding θr, advancing θa, and equilibrium θe contact angles in thin capillaries were calculated on the basis of the shape of the disjoining/conjoining pressure isotherm. It was shown that both advancing and receding contact angles depend on the capillary radius. The suggested mechanism of the contact angle hysteresis has a direct experimental confirmation: the process of receding is accompanied by the formation of thick β-films on the capillary walls. The effect of the transition from partial to complete wetting in thin capillaries is predicted and analyzed. This effect takes place in very thin capillaries, when the receding contact angle decreases to zero.

load-displacement and stability characteristics of tidn-walled beams

African Journals Online (AJOL)

construction. Such structural ... The finite displacement formulation is used for load- displacement .... The other stress term, which is the incremental linear stress term a/ is .... formulation, only two out of the four general governing ..... 119, Paper. No. 2700 ... Deformations Spatial Buckling of Thin-Walled Beams and Frames ...

Domain wall magnetoresistance in BiFeO3 thin films measured by scanning probe microscopy.

Science.gov (United States)

Domingo, N; Farokhipoor, S; Santiso, J; Noheda, B; Catalan, G

2017-08-23

We measure the magnetotransport properties of individual 71° domain walls in multiferroic BiFeO 3 by means of conductive-atomic force microscopy (C-AFM) in the presence of magnetic fields up to one Tesla. The results suggest anisotropic magnetoresistance at room temperature, with the sign of the magnetoresistance depending on the relative orientation between the magnetic field and the domain wall plane. A consequence of this finding is that macroscopically averaged magnetoresistance measurements for domain wall bunches are likely to underestimate the magnetoresistance of each individual domain wall.

Disilane as a growth rate catalyst of plasma deposited microcrystalline silicon thin films

Science.gov (United States)

Dimitrakellis, P.; Kalampounias, A. G.; Spiliopoulos, N.; Amanatides, E.; Mataras, D.; Lahootun, V.; Coeuret, F.; Madec, A.

2016-07-01

The effect of small disilane addition on the gas phase properties of silane-hydrogen plasmas and the microcrystalline silicon thin films growth is presented. The investigation was conducted in the high pressure regime and for constant power dissipation in the discharge with the support of plasma diagnostics, thin film studies and calculations of discharge microscopic parameters and gas dissociation rates. The experimental data and the calculations show a strong effect of disilane on the electrical properties of the discharge in the pressure window from 2 to 3 Torr that is followed by significant raise of the electron number density and the drop of the sheaths electric field intensity. Deposition rate measurements show an important four to six times increase even for disilane mole fractions as low as 0.3 %. The deposition rate enhancement was followed by a drop of the material crystalline volume fraction but films with crystallinity above 40 % were deposited with different combinations of total gas pressure, disilane and silane molar ratios. The enhancement was partly explained by the increase of the electron impact dissociation rate of silane which rises by 40% even for 0.1% disilane mole fraction. The calculations of the gas usage, the dissociation and the deposition efficiencies show that the beneficial effect on the growth rate is not just the result of the increase of Si-containing molecules density but significant changes on the species participating to the deposition and the mechanism of the film growth are caused by the disilane addition. The enhanced participation of the highly sticking to the surface radical such as disilylene, which is the main product of disilane dissociation, was considered as the most probable reason for the significant raise of the deposition efficiency. The catalytic effect of such type of radical on the surface reactivity of species with lower sticking probability is further discussed, while it is also used to explain the restricted

Disilane as a growth rate catalyst of plasma deposited microcrystalline silicon thin films

International Nuclear Information System (INIS)

Dimitrakellis, P.; Amanatides, E.; Mataras, D.; Kalampounias, A. G.; Spiliopoulos, N.; Lahootun, V.; Coeuret, F.; Madec, A.

2016-01-01

The effect of small disilane addition on the gas phase properties of silane-hydrogen plasmas and the microcrystalline silicon thin films growth is presented. The investigation was conducted in the high pressure regime and for constant power dissipation in the discharge with the support of plasma diagnostics, thin film studies and calculations of discharge microscopic parameters and gas dissociation rates. The experimental data and the calculations show a strong effect of disilane on the electrical properties of the discharge in the pressure window from 2 to 3 Torr that is followed by significant raise of the electron number density and the drop of the sheaths electric field intensity. Deposition rate measurements show an important four to six times increase even for disilane mole fractions as low as 0.3 %. The deposition rate enhancement was followed by a drop of the material crystalline volume fraction but films with crystallinity above 40 % were deposited with different combinations of total gas pressure, disilane and silane molar ratios. The enhancement was partly explained by the increase of the electron impact dissociation rate of silane which rises by 40% even for 0.1% disilane mole fraction. The calculations of the gas usage, the dissociation and the deposition efficiencies show that the beneficial effect on the growth rate is not just the result of the increase of Si-containing molecules density but significant changes on the species participating to the deposition and the mechanism of the film growth are caused by the disilane addition. The enhanced participation of the highly sticking to the surface radical such as disilylene, which is the main product of disilane dissociation, was considered as the most probable reason for the significant raise of the deposition efficiency. The catalytic effect of such type of radical on the surface reactivity of species with lower sticking probability is further discussed, while it is also used to explain the restricted

Characteristics of heat transfer fouling of thin stillage using model thin stillage and evaporator concentrates

Science.gov (United States)

Challa, Ravi Kumar

The US fuel ethanol demand was 50.3 billion liters (13.3 billion gallons) in 2012. Corn ethanol was produced primarily by dry grind process. Heat transfer equipment fouling occurs during corn ethanol production and increases the operating expenses of ethanol plants. Following ethanol distillation, unfermentables are centrifuged to separate solids as wet grains and liquid fraction as thin stillage. Evaporator fouling occurs during thin stillage concentration to syrup and decreases evaporator performance. Evaporators need to be shutdown to clean the deposits from the evaporator surfaces. Scheduled and unscheduled evaporator shutdowns decrease process throughput and results in production losses. This research were aimed at investigating thin stillage fouling characteristics using an annular probe at conditions similar to an evaporator in a corn ethanol production plant. Fouling characteristics of commercial thin stillage and model thin stillage were studied as a function of bulk fluid temperature and heat transfer surface temperature. Experiments were conducted by circulating thin stillage or carbohydrate mixtures in a loop through the test section which consisted of an annular fouling probe while maintaining a constant heat flux by electrical heating and fluid flow rate. The change in fouling resistance with time was measured. Fouling curves obtained for thin stillage and concentrated thin stillage were linear with time but no induction periods were observed. Fouling rates for concentrated thin stillage were higher compared to commercial thin stillage due to the increase in solid concentration. Fouling rates for oil skimmed and unskimmed concentrated thin stillage were similar but lower than concentrated thin stillage at 10% solids concentration. Addition of post fermentation corn oil to commercial thin stillage at 0.5% increments increased the fouling rates up to 1% concentration but decreased at 1.5%. As thin stillage is composed of carbohydrates, protein, lipid

Complete Status Report Documenting Weld Development for Thin Wall Tubing of ODS Ferritic Alloys

Energy Technology Data Exchange (ETDEWEB)

Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Edmondson, Philip D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-09-16

Beginning in 2015, research in the FCRD program began the development of FSW for joining thin sections of 14YWT in the form of thin (0.5 mm) plate and ultimately thin wall tubing. In the previous fiscal year, a ~1 mm thick plate, or sheet, of 14YWT was produced by hot rolling with no edge cracking. The initial FSW experiment was performed on the 1 mm thick plate and involved a bead-on-plate weld in which the spinning pin tool is plunged into the plate surface, but does not penetrate the thickness of the plate, and then travels the length of the plate. The FSW run successfully produced a bead-on-plate stir zone on the 1 mm thick plate of 14YWT, but no characterization studies of the stir zone were performed by the end of FY15. Therefore, the results presented in this report cover the microstructural analysis of the bead-on-plate stir zone and the initial research task on obtaining tensile properties of the stir zone using the digital image correlation (DIC) approach during testing of miniature tensile specimens to assess the quality of the FSW parameters used in the initial experiment. The results of the microstructural characterization study using optical, scanning electron and scanning transmission electron microscopies showed the grain structure in the SZ to have isotropic and irregular shape but very similar size compared to the highly elongated grains oriented horizontally with the plane of the plate that were observed in the unaffected zone of 14YWT. Several cracks oriented horizontally were observed mostly on the retreating side of the SZ in both the SZ and TMAZ. These cracks may have formed due to insufficient pressure being exerted on the top surface of the plate by the shoulder and pin tool during the FSW run. High resolution STEM-EDS analysis showed the presence of the Y-Ti-O particles in the SZ, but that some particles exhibited coarsening. Overall, the FSW parameters used to produce the bead-on-plate SZ in the 0.1 cm thick plate of 14YWT were nearly

Characterisation of a complex thin walled structure fabricated by selective laser melting using a ferritic oxide dispersion strengthened steel

Energy Technology Data Exchange (ETDEWEB)

Boegelein, Thomas, E-mail: t.boegelein@liv.ac.uk; Louvis, Eleftherios; Dawson, Karl; Tatlock, Gordon J.; Jones, Andy R.

2016-02-15

Oxide dispersion strengthened (ODS) alloys exhibit superior mechanical and physical properties due to the presence of nanoscopic Y(Al, Ti) oxide precipitates, but their manufacturing process is complex. The present study is aimed at further investigation of the application of an alternative, Additive Manufacturing (AM) technique, Selective Laser Melting (SLM), to the production of consolidated ODS alloy components. Mechanically alloyed PM2000 (ODS-FeCrAl) powders have been consolidated and a fine dispersion of Y-containing precipitates were observed in an as built thin-walled component, but these particles were typically poly-crystalline and contained a variety of elements including O, Al, Ti, Cr and Fe. Application of post-build heat treatments resulted in the modification of particle structures and compositions; in the annealed condition most precipitates were transformed to single crystal yttrium aluminium oxides. During the annealing treatment, precipitate distributions homogenised and localised variations in number density were diminished. The resulting volume fractions of those precipitates were 25–40% lower than have been reported in conventionally processed PM2000, which was attributed to Y-rich slag-like surface features and inclusions formed during SLM. - Highlights: • A wall structure was grown from ODS steel powder using selective laser melting. • A fine dispersion of nano-precipitates was apparent in as-build material. • Precipitates were multi-phased containing several elements, e.g. O, Ti, Al, Fe, Cr, Y. • Post-build annealing changed those into typically single-crystalline Y–Al–O. • The anneal also reduced and stabilised the volume fraction of precipitates to ~ 0.006.

Thin liquid sheet target capabilities for ultra-intense laser acceleration of ions at a kHz repetition rate

Science.gov (United States)

Klim, Adam; Morrison, J.; Orban, C.; Chowdhury, E.; Frische, K.; Feister, S.; Roquemore, M.

2017-10-01

The success of laser-accelerated ion experiments depends crucially on a number of factors including how thin the targets can be created. We present experimental results demonstrating extremely thin (under 200 nm) glycol sheet targets that can be used for ultra-intense laser-accelerated ion experiments conducted at the Air Force Research Laboratory at Wright-Patterson Air Force Base. Importantly, these experiments operate at a kHz repetition rate and the recovery time of the liquid targets is fast enough to allow the laser to interact with a refreshed, thin target on every shot. These thin targets can be used to produce energetic electrons, light ions, and neutrons as well as x-rays, we present results from liquid glycol targets which are useful for proton acceleration experiments via the mechanism of Target Normal Sheath Acceleration (TNSA). In future work, we will create thin sheets from deuterated water in order to perform laser-accelerated deuteron experiments. This research was sponsored by the Quantum and Non-Equilibrium Processes Division of the AFOSR, under the management of Dr. Enrique Parra, and support from the DOD HPCMP Internship Program.

Magnetic domain wall gratings for magnetization reversal tuning and confined dynamic mode localization.

Science.gov (United States)

Trützschler, Julia; Sentosun, Kadir; Mozooni, Babak; Mattheis, Roland; McCord, Jeffrey

2016-08-04

High density magnetic domain wall gratings are imprinted in ferromagnetic-antiferromagnetic thin films by local ion irradiation by which alternating head-to-tail-to-head-to-tail and head-to-head-to-tail-to-tail spatially overlapping domain wall networks are formed. Unique magnetic domain processes result from the interaction of anchored domain walls. Non-linear magnetization response is introduced by the laterally distributed magnetic anisotropy phases. The locally varying magnetic charge distribution gives rise to localized and guided magnetization spin-wave modes directly constrained by the narrow domain wall cores. The exchange coupled multiphase material structure leads to unprecedented static and locally modified dynamic magnetic material properties.

Structural characteristics of the acquired optic disc pit and the rate of progressive retinal nerve fiber layer thinning in primary open-angle glaucoma.

Science.gov (United States)

Lee, Seung Hyen; Lee, Eun Ji; Kim, Tae-Woo

2015-10-01

The optic disc pit (ODP) has been considered a region of localized susceptibility to the damage of glaucoma. To determine whether the rate of retinal nerve fiber layer (RNFL) thinning differs according to the presence and structural characteristics of an ODP in primary open-angle glaucoma. We performed a prospective case-control study that included 163 eyes with primary open-angle glaucoma (83 with an ODP and 80 without an ODP) from Glaucoma Clinic of Seoul National University Bundang Hospital. Participants were enrolled from the ongoing Investigating Glaucoma Progression Study from January 1, 2012, through May 31, 2014. Mean (SD) follow-up was 3.32 (0.49) years (through May 31, 2014). Optic nerve heads underwent swept-source optical coherence tomography (OCT) to determine the presence of focal lamina cribrosa alteration and its structural characteristics. Eyes with and without photographic ODPs and corresponding microscopic laminar alterations were assigned to the ODP and non-ODP groups, respectively. The rates of progressive thinning of global and 6 sectoral spectral-domain OCT RNFL thicknesses were determined by linear regression and compared between the 2 groups. We used a general linear model to determine the factors associated with the rate of RNFL thinning; data obtained from September 21, 2009, through May 31, 2014, were used to calculate the rate of RNFL thinning. The relationship between the presence and structural characteristics of ODPs and the rate of progressive OCT RNFL thinning. Thinning of the RNFL was faster in the ODP group than in the non-ODP group in the global (mean [SD], -1.44 [1.31] vs -0.93 [1.10] [95% CI, -0.97 to -0.19] μm/y; P = .008), temporoinferior (mean [SD], -4.17 [4.15] vs -1.97 [3.26] [95% CI, -3.36 to -1.04] μm/y; P < .001), and temporal (mean [SD], -1.92 [2.62] vs -0.89 [1.62] [95% CI, -1.70 to -0.35] μm/y; P = .003) sectors. The rate of RNFL thinning was maximum in the temporoinferior sector (mean [SD], -4

Effect of gravity on false-vacuum decay rates for O(4)-symmetric bubble nucleation

International Nuclear Information System (INIS)

Samuel, D.A.; Hiscock, W.A.

1991-01-01

The self-gravity of quantum fields is often considered to be a negligible perturbation upon a background spacetime and not of much physical interest. Its importance is determined by the ratio of the mass of the field to the Planck mass, this ratio being very small for those fields that we are most familiar in dealing with. However, it is conceivable that either in the very early Universe or even today a false-vacuum decay could occur associated with a field of appreciable mass. The effect of self-gravity upon false-vacuum decay was initially studied within the ''thin-wall'' approximation by Coleman and De Luccia. Their analysis involved the approximate solution of the coupled Euclideanized field and Einstein equations with the assumption of O(4)-symmetric bubble nucleation. In this paper we consider the range of validity of the ''thin-wall'' approximation by comparing the Coleman--De Luccia results with exact numerical results for a quartic polynomial potential. We also extend the analysis into regimes for which the ''thin-wall'' approximation is inapplicable. In the case of an initially de Sitter space decaying into Minkowski space, we find a smooth transition between the Coleman--De Luccia mode of bubble formation and the Hawking-Moss transition, wherein the entire spacetime tunnels ''at once'' to the maximum of the potential. In the case of the decay of an initially Minkowski space to an anti--de Sitter space, we find that there is a ''forbidden region'' of vacuum potential parameters for which decay is not possible. At energies far below the Planck scale, the boundary of this region is accurately described by the thin-wall prediction obtained by Coleman and De Luccia. At energies near the Planck scale, however, the actual ''forbidden region'' is significantly smaller than predicted by the thin-wall approximation; thus, vacuum decays are possible which appear to be forbidden by thin-wall calculations

Binder-free manganese oxide/carbon nanomaterials thin film electrode for supercapacitors.

Science.gov (United States)

Wang, Ning; Wu, Chuxin; Li, Jiaxin; Dong, Guofa; Guan, Lunhui

2011-11-01

A ternary thin film electrode was created by coating manganese oxide onto a network composed of single-walled carbon nanotubes and single-walled carbon nanohorns. The electrode exhibited a porous structure, which is a promising architecture for supercapacitors applications. The maximum specific capacitances of 357 F/g for total electrode at 1 A/g were achieved in 0.1 M Na(2)SO(4) aqueous solution.

An analytical method for calculating stresses and strains of ATF cladding based on thick walled theory

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong Hyun; Kim, Hak Sung [Hanyang University, Seoul (Korea, Republic of); Kim, Hyo Chan; Yang, Yong Sik; In, Wang kee [KAERI, Daejeon (Korea, Republic of)

2016-05-15

In this paper, an analytical method based on thick walled theory has been studied to calculate stress and strain of ATF cladding. In order to prescribe boundary conditions of the analytical method, two algorithms were employed which are called subroutine 'Cladf' and 'Couple' of FRACAS, respectively. To evaluate the developed method, equivalent model using finite element method was established and stress components of the method were compared with those of equivalent FE model. One of promising ATF concepts is the coated cladding, which take advantages such as high melting point, a high neutron economy, and low tritium permeation rate. To evaluate the mechanical behavior and performance of the coated cladding, we need to develop the specified model to simulate the ATF behaviors in the reactor. In particular, the model for simulation of stress and strain for the coated cladding should be developed because the previous model, which is 'FRACAS', is for one body model. The FRACAS module employs the analytical method based on thin walled theory. According to thin-walled theory, radial stress is defined as zero but this assumption is not suitable for ATF cladding because value of the radial stress is not negligible in the case of ATF cladding. Recently, a structural model for multi-layered ceramic cylinders based on thick-walled theory was developed. Also, FE-based numerical simulation such as BISON has been developed to evaluate fuel performance. An analytical method that calculates stress components of ATF cladding was developed in this study. Thick-walled theory was used to derive equations for calculating stress and strain. To solve for these equations, boundary and loading conditions were obtained by subroutine 'Cladf' and 'Couple' and applied to the analytical method. To evaluate the developed method, equivalent FE model was established and its results were compared to those of analytical model. Based on the

Lignocellulose-derived thin stillage composition and efficient biological treatment with a high-rate hybrid anaerobic bioreactor system

KAUST Repository

Oosterkamp, Margreet J.

2016-06-06

Background This study aims to chemically characterize thin stillage derived from lignocellulosic biomass distillation residues in terms of organic strength, nutrient, and mineral content. The feasibility of performing anaerobic digestion on these stillages at mesophilic (40 °C) and thermophilic (55 °C) temperatures to produce methane was demonstrated. The microbial communities involved were further characterized. Results Energy and sugar cane stillage have a high chemical oxygen demand (COD of 43 and 30 g/L, respectively) and low pH (pH 4.3). Furthermore, the acetate concentration in sugar cane stillage was high (45 mM) but was not detected in energy cane stillage. There was also a high amount of lactate in both types of stillage (35–37 mM). The amount of sugars was 200 times higher in energy cane stillage compared to sugar cane stillage. Although there was a high concentration of sulfate (18 and 23 mM in sugar and energy cane stillage, respectively), both thin stillages were efficiently digested anaerobically with high COD removal under mesophilic and thermophilic temperature conditions and with an organic loading rate of 15–21 g COD/L/d. The methane production rate was 0.2 L/g COD, with a methane percentage of 60 and 64, and 92 and 94 % soluble COD removed, respectively, by the mesophilic and thermophilic reactors. Although both treatment processes were equally efficient, there were different microbial communities involved possibly arising from the differences in the composition of energy cane and sugar cane stillage. There was more acetic acid in sugar cane stillage which may have promoted the occurrence of aceticlastic methanogens to perform a direct conversion of acetate to methane in reactors treating sugar cane stillage. Conclusions Results showed that thin stillage contains easily degradable compounds suitable for anaerobic digestion and that hybrid reactors can efficiently convert thin stillage to methane under mesophilic and thermophilic conditions

Lignocellulose-derived thin stillage composition and efficient biological treatment with a high-rate hybrid anaerobic bioreactor system.