Modeling Restrained Shrinkage Induced Cracking in Concrete Rings Using the Thick Level Set Approach

Directory of Open Access Journals (Sweden)

Rebecca Nakhoul

2018-03-01

Full Text Available Modeling restrained shrinkage-induced damage and cracking in concrete is addressed herein. The novel Thick Level Set (TLS damage growth and crack propagation model is used and adapted by introducing shrinkage contribution into the formulation. The TLS capacity to predict damage evolution, crack initiation and growth triggered by restrained shrinkage in absence of external loads is evaluated. A study dealing with shrinkage-induced cracking in elliptical concrete rings is presented herein. Key results such as the effect of rings oblateness on stress distribution and critical shrinkage strain needed to initiate damage are highlighted. In addition, crack positions are compared to those observed in experiments and are found satisfactory.

Iterative approach as alternative to S-matrix in modal methods

Science.gov (United States)

Semenikhin, Igor; Zanuccoli, Mauro

2014-12-01

The continuously increasing complexity of opto-electronic devices and the rising demands of simulation accuracy lead to the need of solving very large systems of linear equations making iterative methods promising and attractive from the computational point of view with respect to direct methods. In particular, iterative approach potentially enables the reduction of required computational time to solve Maxwell's equations by Eigenmode Expansion algorithms. Regardless of the particular eigenmodes finding method used, the expansion coefficients are computed as a rule by scattering matrix (S-matrix) approach or similar techniques requiring order of M3 operations. In this work we consider alternatives to the S-matrix technique which are based on pure iterative or mixed direct-iterative approaches. The possibility to diminish the impact of M3 -order calculations to overall time and in some cases even to reduce the number of arithmetic operations to M2 by applying iterative techniques are discussed. Numerical results are illustrated to discuss validity and potentiality of the proposed approaches.

Influence of Shrinkage-Reducing Admixtures on the Development of Plastic Shrinkage Cracks

DEFF Research Database (Denmark)

Lura, Pietro; Pease, Bradley Justin; Mazzotta, Guy

2007-01-01

The term plastic shrinkage cracking is generally used to describe cracks that form between the time when concrete is placed and the time when concrete sets. This paper discusses how the evaporation of water causes concave menisci to form on the surface of fresh concrete. These menisci cause both...... settlement of the concrete and tensile stress development in the surface of the concrete, which increase the potential for development of plastic shrinkage cracks. Specifically, this paper studies the development of plastic shrinkage cracks in mortars containing a commercially available shrinkage-reducing...... admixture (SRA). Mortars containing SRA show fewer and narrower plastic shrinkage cracks than plain mortars when exposed to the same environmental conditions. It is proposed that the lower surface tension of the pore fluid in the mortars containing SRA results in less evaporation, reduced settlement...

Study on effects of solar radiation and rain on shrinkage, shrinkage cracking and creep of concrete

International Nuclear Information System (INIS)

Asamoto, Shingo; Ohtsuka, Ayumu; Kuwahara, Yuta; Miura, Chikako

2011-01-01

In this paper, the effects of actual environmental actions on shrinkage, creep and shrinkage cracking of concrete are studied comprehensively. Prismatic specimens of plain concrete were exposed to three sets of artificial outdoor conditions with or without solar radiation and rain to examine the shrinkage. For the purpose of studying shrinkage cracking behavior, prismatic concrete specimens with reinforcing steel were also subjected to the above conditions at the same time. The shrinkage behavior is described focusing on the effects of solar radiation and rain based on the moisture loss. The significant environment actions to induce shrinkage cracks are investigated from viewpoints of the amount of the shrinkage and the tensile strength. Finally, specific compressive creep behavior according to solar radiation and rainfall is discussed. It is found that rain can greatly inhibit the progresses of concrete shrinkage and creep while solar radiation is likely to promote shrinkage cracking and creep.

A new approach of equilibrium reconstruction for ITER

International Nuclear Information System (INIS)

Imazawa, R.; Kawano, Y.; Kusama, Y.

2011-01-01

We have proposed a new approach for equilibrium reconstruction that can be applied to ITER-like burning plasmas. In this study, we have focused on carrying out equilibrium reconstruction using polarimetry, which is feasible for ITER-like burning plasmas. Polarimetry in burning plasmas is different from that in the existing tokamaks in two regards: (1) increased importance of the relativistic effects and (2) significant coupling with the Faraday and Cotton–Mouton effects. We found that when polarimetric data (orientation angle, θ, and ellipticity angle, ε, of a polarization state) are used as the constraints in the equilibrium reconstruction, the optimum weighting factors for θ and ε depend on the magnetic surfaces through which the viewing chord of polarimetry passes. We applied our approach to the operation scenarios II (S2) and IV (S4) in ITER. In the case where the viewing chords are via both the equatorial and upper ports, the measurement requirements for the accuracy of the q-profile in ITER (±10%) were satisfied in S2 and S4 when the measuring errors of θ and ε were less than 0.5° and 3°, respectively.

Prevention of shrinkage cracking in tight concrete structures

International Nuclear Information System (INIS)

Alvaredo, A.M.; Wittmann, F.H.

1995-01-01

It is shown that crack formation and propagation in concrete members subjected to restrained shrinkage can be realistically predicted by means of a comprehensive approach including a diffusion analysis and fracture mechanics considerations. The conditions for stable crack propagation regarding dimensions of the concrete member, degree of restraint to the imposed deformation and material properties are discussed. Guidelines on the prevention of shrinkage cracking of concrete structures are given. (author). 10 refs., 5 figs

Methods for measuring shrinkage

OpenAIRE

Chapman, Paul; Templar, Simon

2006-01-01

This paper presents findings from research amongst European grocery retailers into their methods for measuring shrinkage. The findings indicate that: there is no dominant method for valuing or stating shrinkage; shrinkage in the supply chain is frequently overlooked; data is essential in pinpointing where and when loss occurs and that many retailers collect data at the stock-keeping unit (SKU) level and do so every 6 months. These findings reveal that it is difficult to benc...

Cure shrinkage in casting resins

Energy Technology Data Exchange (ETDEWEB)

Spencer, J. Brock [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-02-01

A method is described whereby the shrinkage of a casting resin can be determined. Values for the shrinkage of several resin systems in frequent use by Sandia have been measured. A discussion of possible methods for determining the stresses generated by cure shrinkage and thermal contraction is also included.

Shrinkage Reducing Admixture for Concrete

OpenAIRE

ECT Team, Purdue

2007-01-01

Concrete shrinkage cracking is a common problem in all types of concrete structures, especially for structures and environments where the cracks are prevalent and the repercussions are most severe. A liquid shrinkage reducing admixture for concrete, developed by GRACE Construction Products and ARCO Chemical Company, that reduces significantly the shrinkage during concrete drying and potentially reduces overall cracking over time.

The iterative shrinkage method for impulsive noise reduction from images

International Nuclear Information System (INIS)

Beygi, Sajjad; Kafashan, Mohammadmehdi; Bahrami, Hamid Reza; Mugler, Dale H

2012-01-01

In this paper, we present a novel scheme to compensate impulsive noise from images using the sparse shrinkage method. In this scheme, we assume the remaining noise after using a simple median filtering in place of corrupted pixels, found by boundary discriminative noise detection method, to be Gaussian additive noise. This assumption will later be verified by the means of simulation. Knowing that the pure image in the discrete wavelet transform (DWT) domain is a sparse vector, we define an optimization problem to minimize the l 0 -norm of the estimated image vector from the noisy one in the DWT domain. l 0 -norm makes the optimization problem a combinatorial optimization problem which is NP-hard to solve. To come up with a solution for our optimization problem, we convert the l 0 -norm problem to a continuous optimization problem which is then solved to find the estimated image with reduced noise. In the simulation and discussion part, the performance of our proposed method in reducing impulsive noise is compared to that of existing methods in the literature. We show that our proposed algorithm generally performs better in terms of both subjective and objective evaluations and is less complex. (paper)

Accounting for PDMS shrinkage when replicating structures

DEFF Research Database (Denmark)

Madsen, Morten Hannibal; Feidenhans'l, Nikolaj Agentoft; Hansen, Poul-Erik

2014-01-01

are seldom applied to counteract the shrinkage of PDMS. Also, to perform metrological measurements using replica techniques one has to take the shrinkage into account. Thus we report a study of the shrinkage of PDMS with several different mixing ratios and curing temperatures. The shrinkage factor, with its...

Effect of Dolomite as Expansive Agent and Shrinkage Reducing Admixture in Self-Compacting Shrinkage – Compensating Concrete

OpenAIRE

Qosai Sahib Radi Marshdi; Ahlam Hamid Jasim; Haider Abass Obeed

2018-01-01

The principle of using expansive agents has been recommended to manufacture shrinkage compensating concrete provided that an adequate wet curing is carried out. On the other hand, shrinkage-reducing admixture (SRA) in the concrete mixes, has been more recently suggested to reduce the risk of cracking in concrete structures caused by drying shrinkage. This paper is devoted to the study of the influence of complex modifier in the form of superplasticizer, shrinkage reducing admixture and e...

Performing Systematic Literature Reviews with Novices: An Iterative Approach

Science.gov (United States)

Lavallée, Mathieu; Robillard, Pierre-N.; Mirsalari, Reza

2014-01-01

Reviewers performing systematic literature reviews require understanding of the review process and of the knowledge domain. This paper presents an iterative approach for conducting systematic literature reviews that addresses the problems faced by reviewers who are novices in one or both levels of understanding. This approach is derived from…

Mitigation strategies for autogenous shrinkage cracking

DEFF Research Database (Denmark)

Bentz, Dale P.; Jensen, Ole Mejlhede

2004-01-01

As the use of high-performance concrete has increased, problems with early-age cracking have become prominent. The reduction in water-to-cement ratio, the incorporation of silica fume, and the increase in binder content of high-performance concretes all contribute to this problem. In this paper......, the fundamental parameters contributing to the autogenous shrinkage and resultant early-age cracking of concrete are presented. Basic characteristics of the cement paste that contribute to or control the autogenous shrinkage response include the surface tension of the pore solution, the geometry of the pore...... of early-age cracking due to autogenous shrinkage. Mitigation strategies discussed in this paper include: the addition of shrinkage-reducing admixtures more commonly used to control drying shrinkage, control of the cement particle size distribution, modification of the mineralogical composition...

Soil shrinkage characteristics in swelling soils

International Nuclear Information System (INIS)

Taboada, M.A.

2004-01-01

The objectives of this presentation are to understand soil swelling and shrinkage mechanisms, and the development of desiccation cracks, to distinguish between soils having different magnitude of swelling, as well as the consequences on soil structural behaviour, to know methods to characterize soil swell/shrink potential and to construct soil shrinkage curves, and derive shrinkage indices, as well to apply them to assess soil management effects

A functional approach for managing ITER operations

International Nuclear Information System (INIS)

Houtte, Didier van; Sagot, François; Okayama, Katsumi; Blackler, Kenneth

2012-01-01

Highlights: ► A function-oriented approach for defining and organizing all the functions required to perform the mission has been developed. ► A Functional Breakdown Structure providing a complete hierarchy of functions on multiple levels is presented. ► The FBS is used for giving a good visibility of ITER project needs and requirements. ► Reliability (R) and Inherent Availability (A I ) of basic functions are calculated from data on the structures, systems and components (failure rate and time to repair) for obtaining the Availability objectives of the ITER project. - Abstract: ITER is currently the most ambitious project on nuclear fusion research. Its objective is to demonstrate the feasibility of fusion as an energy source for the future. The complexity of the systems required to meet this challenge present many opportunities for omissions or incorrect assumptions. System engineering allows the engineer to deal with such a complexity by developing a Functional Breakdown Structure (FBS). Unlike a Plant Breakdown Structure (PBS), the FBS is a function-oriented tree, not a product-oriented tree. It details operations or activities that have to be performed as needed functions of the architecture, allowing identification of any missing elements, defining the personnel skills required to operate the architecture and managing the machine availability.

Regularization iteration imaging algorithm for electrical capacitance tomography

Science.gov (United States)

Tong, Guowei; Liu, Shi; Chen, Hongyan; Wang, Xueyao

2018-03-01

The image reconstruction method plays a crucial role in real-world applications of the electrical capacitance tomography technique. In this study, a new cost function that simultaneously considers the sparsity and low-rank properties of the imaging targets is proposed to improve the quality of the reconstruction images, in which the image reconstruction task is converted into an optimization problem. Within the framework of the split Bregman algorithm, an iterative scheme that splits a complicated optimization problem into several simpler sub-tasks is developed to solve the proposed cost function efficiently, in which the fast-iterative shrinkage thresholding algorithm is introduced to accelerate the convergence. Numerical experiment results verify the effectiveness of the proposed algorithm in improving the reconstruction precision and robustness.

ITER-FEAT safety

International Nuclear Information System (INIS)

Gordon, C.W.; Bartels, H.-W.; Honda, T.; Raeder, J.; Topilski, L.; Iseli, M.; Moshonas, K.; Taylor, N.; Gulden, W.; Kolbasov, B.; Inabe, T.; Tada, E.

2001-01-01

Safety has been an integral part of the design process for ITER since the Conceptual Design Activities of the project. The safety approach adopted in the ITER-FEAT design and the complementary assessments underway, to be documented in the Generic Site Safety Report (GSSR), are expected to help demonstrate the attractiveness of fusion and thereby set a good precedent for future fusion power reactors. The assessments address ITER's radiological hazards taking into account fusion's favourable safety characteristics. The expectation that ITER will need regulatory approval has influenced the entire safety design and assessment approach. This paper summarises the ITER-FEAT safety approach and assessments underway. (author)

Volumetric polymerization shrinkage of contemporary composite resins

Directory of Open Access Journals (Sweden)

Halim Nagem Filho

2007-10-01

Full Text Available The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill Magic, Alert, and Solitaire to determine whether there are differences among these materials. The tests were conducted with precision of 0.1 mg. The volumetric shrinkage was measured by hydrostatic weighing before and after polymerization and calculated by known mathematical equations. One-way ANOVA (a or = 0.05 was used to determine statistically significant differences in volumetric shrinkage among the tested composite resins. Suprafill (1.87±0.01 and Definite (1.89±0.01 shrank significantly less than the other composite resins. SureFil (2.01±0.06, Filtek Z250 (1.99±0.03, and Fill Magic (2.02±0.02 presented intermediate levels of polymerization shrinkage. Alert and Solitaire presented the highest degree of polymerization shrinkage. Knowing the polymerization shrinkage rates of the commercially available composite resins, the dentist would be able to choose between using composite resins with lower polymerization shrinkage rates or adopting technical or operational procedures to minimize the adverse effects deriving from resin contraction during light-activation.

Silorane- and high filled-based"low-shrinkage" resin composites: shrinkage, flexural strength and modulus

Directory of Open Access Journals (Sweden)

Cesar Augusto Galvão Arrais

2013-04-01

Full Text Available This study compared the volumetric shrinkage (VS, flexural strength (FS and flexural modulus (FM properties of the low-shrinkage resin composite Aelite LS (Bisco to those of Filtek LS (3M ESPE and two regular dimethacrylate-based resin composites, the microfilled Heliomolar (Ivoclar Vivadent and the microhybrid Aelite Universal (Bisco. The composites (n = 5 were placed on the Teflon pedestal of a video-imaging device, and VS was recorded every minute for 5 min after 40 s of light exposure. For the FS and FM tests, resin discs (0.6 mm in thickness and 6.0 mm in diameter were obtained (n = 12 and submitted to a piston-ring biaxial test in a universal testing machine. VS, FS, and FM data were submitted to two-way repeated measures and one-way ANOVA, respectively, followed by Tukey's post-hoc test (a = 5%. Filtek LS showed lower VS than did Aelite LS, which in turn showed lower shrinkage than did the other composites. Aelite Universal and Filtek LS exhibited higher FS than did Heliomolar and Aelite LS, both of which exhibited the highest FM. No significant difference in FM was noted between Filtek LS and Aelite Universal, while Heliomolar exhibited the lowest values. Aelite LS was not as effective as Filtek LS regarding shrinkage, although both low-shrinkage composites showed lower VS than did the other composites. Only Filtek LS exhibited FS and FM comparable to those of the regular microhybrid dimethacrylate-based resin composite.

Iterative local Chi2 alignment approach for the ATLAS SCT detector

CERN Document Server

Härtel, Roland

An approach for the alignment of SCT modules in the ATLAS Inner Detector with particle tracks was developed and implemented in the ATLAS software framework Athena. The approach uses distance of closest approach residuals and a linear least squares minimization to derive the most probable set of alignment parameters for each module. The procedure is iterative, i.e. with the first set of alignment constants a track refit is done and the alignment algorithm is repeated. Correlations between modules are only implicitly taken into account due to the improvement of track parameters through the iterations. A derivation of the underlying concepts is presented. The achievable accuracy and limits of the alignment approach were studied with Monte Carlo simulated tracks in the Athena framework. The results and limitations obtained with the present versions of Athena and the proposed alignment software are presented.

Design approach for safe tritium handling in ITER

International Nuclear Information System (INIS)

Ohira, Shigeru

2002-01-01

Outlines for tritium handling and a fundamental approach for ensuring safety are presented. The amount of tritium stored and processed in the ITER facility will be much larger than that in the existing facilities for fusion research, though the processing methods and the conditions of processing (e.g., concentration, pressure, etc.) will be similar for those used in those facilities. Therefore, considerations to be taken for tritium handling, such as limitations of tritium permeation and leaks, provision of an appropriate ventilation/detritiation system for maintenance, measures to ensure mechanical integrity, etc., can be provided based on the knowledge obtained in the facilities. The Technical Advisory Committee of the Science and Technology Agency established a fundamental approach in 2000, and set out the basic safety principles and approaches as technical requirements of safety design and assessment, which were derived from the safety characteristics of the ITER plant. Sufficient prevention of accidents can be achieved by ensuring and maintaining the structural integrity of the enclosures containing radioactive materials against the loads anticipated during operation, and a low hazard potential of radioactive materials, sufficiently within prescribed limits, can be maintained by the vitiation and clean-up system even if large release is postulated. (author)

Distinct spontaneous shrinkage of a sporadic vestibular schwannoma

DEFF Research Database (Denmark)

Huang, Xiaowen; Cayé-Thomasen, Per; Stangerup, Sven-Eric

2013-01-01

on "shrinkage" or "negative growth" or "regression" or "involution" of the tumor were selected, and the contents on the rate, extent and mechanism of spontaneous tumor shrinkage were extracted and reviewed. The reported rate of spontaneous shrinkage of vestibular schwannoma is 5-10% of patients managed......We present a case with outspoken spontaneous vestibular schwannoma shrinkage and review the related literature. The patient was initially diagnosed with a left-sided, intrameatal vestibular schwannoma, which subsequently grew into the cerebello-pontine angle (CPA), followed by total shrinkage...... of the CPA component without any intervention over a 12-year observation period. The literature on spontaneous tumor shrinkage was retrieved by searching the subject terms "vestibular schwannoma, conservative management" in PubMed/MEDLINE database, without a time limit. Of the published data, the articles...

Dynamics of tissue shrinkage during ablative temperature exposures

International Nuclear Information System (INIS)

Rossmann, Christian; Haemmerich, Dieter; Garrett-Mayer, Elizabeth; Rattay, Frank

2014-01-01

There is a lack of studies that examine the dynamics of heat-induced shrinkage of organ tissues. Clinical procedures such as radiofrequency ablation, microwave ablation or high-intensity focused ultrasound, use heat to treat diseases such as cancer and cardiac arrhythmia. When heat is applied to tissues, shrinkage occurs due to protein denaturation, dehydration and contraction of collagen at temperatures greater 50 °C. This is particularly relevant for image-guided procedures such as tumor ablation, where pre- and post-treatment images are compared and any changes in dimensions must be considered to avoid misinterpretations of the treatment outcome. We present data from ex vivo, isothermal shrinkage tests in porcine liver tissue, where axial changes in tissue length were recorded during 15 min of heating to temperatures between 60 and 95 °C. A mathematical model was developed to accurately describe the time and temperature-dependent shrinkage behavior. The shrinkage dynamics had the same characteristics independent of temperature; the estimated relative shrinkage, adjusted for time since death, after 15 min heating to temperatures of 60, 65, 75, 85 and 95 °C, was 12.3, 13.8, 16.6, 19.2 and 21.7%, respectively. Our results demonstrate the shrinkage dynamics of organ tissues, and suggest the importance of considering tissue shrinkage for thermal ablative treatments. (paper)

The shrinkage of hardening cement paste and mortar

NARCIS (Netherlands)

Haas, de G.D.; Kreijger, P.C.; Niël, E.M.M.G.; Slagter, J.C.; Stein, H.N.; Theissing, E.M.; Wallendael, van M.

1975-01-01

This paper is an abstract from the report of the commission B10: "The influence of the shrinkage of cement on the shrink-age of concrete", of the Netherlands Committee for Concrete Research. Measurements of pulse velocity, volume shrinkage and heat of hydration on hardening portland cement support

Water storage change estimation from in situ shrinkage measurements of clay soils

Directory of Open Access Journals (Sweden)

B. te Brake

2013-05-01

Full Text Available The objective of this study is to assess the applicability of clay soil elevation change measurements to estimate soil water storage changes, using a simplified approach. We measured moisture contents in aggregates by EC-5 sensors, and in multiple aggregate and inter-aggregate spaces (bulk soil by CS616 sensors. In a long dry period, the assumption of constant isotropic shrinkage proved invalid and a soil moisture dependant geometry factor was applied. The relative overestimation made by assuming constant isotropic shrinkage in the linear (basic shrinkage phase was 26.4% (17.5 mm for the actively shrinking layer between 0 and 60 cm. Aggregate-scale water storage and volume change revealed a linear relation for layers ≥ 30 cm depth. The range of basic shrinkage in the bulk soil was limited by delayed drying of deep soil layers, and maximum water loss in the structural shrinkage phase was 40% of total water loss in the 0–60 cm layer, and over 60% in deeper layers. In the dry period, fitted slopes of the ΔV–ΔW relationship ranged from 0.41 to 0.56 (EC-5 and 0.42 to 0.55 (CS616. Under a dynamic drying and wetting regime, slopes ranged from 0.21 to 0.38 (EC-5 and 0.22 to 0.36 (CS616. Alternating shrinkage and incomplete swelling resulted in limited volume change relative to water storage change. The slope of the ΔV–ΔW relationship depended on the drying regime, measurement scale and combined effect of different soil layers. Therefore, solely relying on surface level elevation changes to infer soil water storage changes will lead to large underestimations. Recent and future developments might provide a basis for application of shrinkage relations to field situations, but in situ observations will be required to do so.

Thermal shrinkage for shoulder instability.

Science.gov (United States)

Toth, Alison P; Warren, Russell F; Petrigliano, Frank A; Doward, David A; Cordasco, Frank A; Altchek, David W; O'Brien, Stephen J

2011-07-01

Thermal capsular shrinkage was popular for the treatment of shoulder instability, despite a paucity of outcomes data in the literature defining the indications for this procedure or supporting its long-term efficacy. The purpose of this study was to perform a clinical evaluation of radiofrequency thermal capsular shrinkage for the treatment of shoulder instability, with a minimum 2-year follow-up. From 1999 to 2001, 101 consecutive patients with mild to moderate shoulder instability underwent shoulder stabilization surgery with thermal capsular shrinkage using a monopolar radiofrequency device. Follow-up included a subjective outcome questionnaire, discussion of pain, instability, and activity level. Mean follow-up was 3.3 years (range 2.0-4.7 years). The thermal capsular shrinkage procedure failed due to instability and/or pain in 31% of shoulders at a mean time of 39 months. In patients with unidirectional anterior instability and those with concomitant labral repair, the procedure proved effective. Patients with multidirectional instability had moderate success. In contrast, four of five patients with isolated posterior instability failed. Thermal capsular shrinkage has been advocated for the treatment of shoulder instability, particularly mild to moderate capsular laxity. The ease of the procedure makes it attractive. However, our retrospective review revealed an overall failure rate of 31% in 80 patients with 2-year minimum follow-up. This mid- to long-term cohort study adds to the literature lacking support for thermal capsulorrhaphy in general, particularly posterior instability. The online version of this article (doi:10.1007/s11420-010-9187-7) contains supplementary material, which is available to authorized users.

Thermal Shrinkage for Shoulder Instability

OpenAIRE

Toth, Alison P.; Warren, Russell F.; Petrigliano, Frank A.; Doward, David A.; Cordasco, Frank A.; Altchek, David W.; O’Brien, Stephen J.

2010-01-01

Thermal capsular shrinkage was popular for the treatment of shoulder instability, despite a paucity of outcomes data in the literature defining the indications for this procedure or supporting its long-term efficacy. The purpose of this study was to perform a clinical evaluation of radiofrequency thermal capsular shrinkage for the treatment of shoulder instability, with a minimum 2-year follow-up. From 1999 to 2001, 101 consecutive patients with mild to moderate shoulder instability underwent...

Large-proportional shrunken bio-replication of shark skin based on UV-curing shrinkage

International Nuclear Information System (INIS)

Chen, Huawei; Che, Da; Zhang, Xin; Yue, Yue; Zhang, Deyuan

2015-01-01

The shark skin effect has attracted worldwide attention because of its superior drag reduction. As the product of natural selection, the maximum drag reduction of shark skin is found in its normal living environment. Large-proportional shrinkage of shark skin morphology is greatly anticipated for its adaptation to faster fluid flow. One novel approach, large-proportional shrunken bio-replication, is proposed as a method to adjust the optimal drag reduction region of shark skin based on the shrinkage of UV-cured material. The shark skin is taken as a replica template to allow large-proportional shrinking in the drag reduction morphology by taking advantage of the shrinkage of UV-curable material. The accuracy of the large-proportional shrunken bio-replication approach is verified by a comparison between original and shrunken bio-replicated shark skin, which shows that the shrinking ratio can reach 23% and the bio-replication accuracy is higher than 95%. In addition, the translation of the optimum drag reduction peak of natural surface function to various applications and environments is proved by drag reduction experiments. (technical note)

Recovering a coefficient in a parabolic equation using an iterative approach

Science.gov (United States)

Azhibekova, Aliya S.

2016-06-01

In this paper we are concerned with the problem of determining a coefficient in a parabolic equation using an iterative approach. We investigate an inverse coefficient problem in the difference form. To recover the coefficient, we minimize a residual functional between the observed and calculated values. This is done in a constructive way by fitting a finite-difference approximation to the inverse problem. We obtain some theoretical estimates for a direct and adjoint problem. Using these estimates we prove monotonicity of the objective functional and the convergence of iteration sequences.

Autogenous shrinkage in high-performance cement paste: An evaluation of basic mechanisms

DEFF Research Database (Denmark)

Lura, Pietro; Jensen, Ole Mejlhede; van Breugel, Klaas

2003-01-01

In this paper, various mechanisms Suggested to cause autogenous shrinkage are presented. The mechanisms are evaluated from the point of view of their soundness and applicability to quantitative modeling of autogenous shrinkage. The capillary tension approach is advantageous, because it has a sound...... mechanical and thermodynamical basis. Furthermore, this mechanism is easily applicable in a numerical model when dealing with a continuously changing microstructure. In order to test the numerical model, autogenous deformation and internal relative humidity (RH) of a Portland cement paste were measured...... on the capillary tension approach. Because a part of the RH drop in the cement paste is due to dissolved salts in the pore solution, a method is suggested to separate this effect from self-desiccation and to calculate the actual stress in the pore fluid associated with menisci formation....

The influence of shrinkage reducing admixtures on plastic shrinkage

Directory of Open Access Journals (Sweden)

Mora, J.

2003-12-01

Full Text Available Shrinkage reducing admixtures (SRAs are viable alternatives for reducing plastic shrinkage cracking in concrete. The objective of the present paper is to study early age plastic shrinkage in restrained concrete elements, where three different SRAs have been used. The influence of the admixture is analyzed through the following measurements: capillary pressure, evaporation, temperature evolution, crack evolution and settlement. The tests for studying the cracking and deformation were made on two different configurations (i.e., restrained prisms with reduced cross-section and restrained panel, in a wind tunnel, with controlled wind temperature and velocity. The conclusions obtained indicate the viability of the use of this type of admixture and the usefulness of the test methods.

Los aditivos reductores de retracción (SRAs se plantean, hoy en día, como una alternativa viable para reducir la fisuración por retracción plástica. El objetivo del presente artículo es conocer mejor y predecir el comportamiento a primeras edades de la retracción plástica en elementos estructurales coaccionados, a los que se les ha añadido diversos aditivos reductores de retracción (tres tipos diferentes. Esta influencia se analiza a través de las siguientes propiedades: presión capilar, evaporación, evolución de temperaturas, evolución de fisuración, y deformaciones verticales de asentamiento. Los ensayos para estudiar la fisuración y las deformaciones se han realizado sobre diferentes configuraciones (prisma restringido con estrangulamiento y panel restringido, en un túnel de viento, con temperaturas y velocidades de viento controladas. Las conclusiones obtenidas señalan la viabilidad del empleo de este tipo de aditivos y la bondad de los métodos experimentales utilizados.

Assessment of concrete creep and shrinkage

International Nuclear Information System (INIS)

Trivedi, Neha; Singh, R.K.

2012-01-01

B-3 model prediction of concrete creep and shrinkage strains on cylindrical specimen and BARC Containment test model (BARCOM) are presented. Experimental shrinkage strain is shown to be in agreement with B-3 model predictions for cylindrical specimen and BARCOM. Creep strain in cylindrical specimen is found to be in agreement with B-3 model. In BARCOM for wall cast in different pores, creep strain is in agreement with B-3 model in hoop direction however in longitudinal direction, observed creep strain in higher than B-3 model. For dome structure cast in a single pour, experimental creep strain shows confirmity with B-3 model both in hoop and longitudinal directions. The study on concrete aging and average longitudinal shrinkage strain is carried out. (author)

Backtracking-Based Iterative Regularization Method for Image Compressive Sensing Recovery

Directory of Open Access Journals (Sweden)

Lingjun Liu

2017-01-01

Full Text Available This paper presents a variant of the iterative shrinkage-thresholding (IST algorithm, called backtracking-based adaptive IST (BAIST, for image compressive sensing (CS reconstruction. For increasing iterations, IST usually yields a smoothing of the solution and runs into prematurity. To add back more details, the BAIST method backtracks to the previous noisy image using L2 norm minimization, i.e., minimizing the Euclidean distance between the current solution and the previous ones. Through this modification, the BAIST method achieves superior performance while maintaining the low complexity of IST-type methods. Also, BAIST takes a nonlocal regularization with an adaptive regularizor to automatically detect the sparsity level of an image. Experimental results show that our algorithm outperforms the original IST method and several excellent CS techniques.

PLASTIC SHRINKAGE CONTROLLING EFFECT BY POLYPROPYLENE SHORT FIBER WITH HYDROPHILY

Science.gov (United States)

Hosoda, Akira; Sadatsuki, Yoshitomo; Oshima, Akihiro; Ishii, Akina; Tsubaki, Tatsuya

The aim of this research is to clarify the mechanism of controlling plastic shrinkage crack by adding small amout of synthetic short fiber, and to propose optimum polypropylene short fiber to control plastic shrinkage crack. In this research, the effect of the hydrophily of polypropylene fiber was investigated in the amount of plastic shrinkage of mortar, total area of plastic shrinkage crack, and bond properties between fiber and mortar. The plastic shrinkage test of morar was conducted under high temperature, low relative humidity, and constant wind velocity. When polypropylene fiber had hydrophily, the amount of plastic shrinkage of mortar was restrained, which was because cement paste in morar was captured by hydrophilic fiber and then bleeding of mortar was restrained. With hydrophily, plastic shrinkage of mortar was restrained and bridging effect was improved due to better bond, which led to remarkable reduction of plastic shrinkage crack. Based on experimental results, the way of developing optimum polypropylene short fiber for actual construction was proposed. The fiber should have large hydrophily and small diameter, and should be used in as small amount as possible in order not to disturb workability of concrete.

Iterating skeletons

DEFF Research Database (Denmark)

Dieterle, Mischa; Horstmeyer, Thomas; Berthold, Jost

2012-01-01

a particular skeleton ad-hoc for repeated execution turns out to be considerably complicated, and raises general questions about introducing state into a stateless parallel computation. In addition, one would strongly prefer an approach which leaves the original skeleton intact, and only uses it as a building...... block inside a bigger structure. In this work, we present a general framework for skeleton iteration and discuss requirements and variations of iteration control and iteration body. Skeleton iteration is expressed by synchronising a parallel iteration body skeleton with a (likewise parallel) state......Skeleton-based programming is an area of increasing relevance with upcoming highly parallel hardware, since it substantially facilitates parallel programming and separates concerns. When parallel algorithms expressed by skeletons involve iterations – applying the same algorithm repeatedly...

Final report of the ITER EDA. Final report of the ITER Engineering Design Activities. Prepared by the ITER Council

International Nuclear Information System (INIS)

2001-01-01

This is the Final Report by the ITER Council on work carried out by ITER participating countries on cooperation in the Engineering Design Activities (EDA) for the ITER. In this report the main ITER EDA technical objectives, the scope of ITER EDA, its organization and resources, engineering design of ITER tokamak and its main parameters are presented. This Report also includes safety and environmental assessments, site requirements and proposed schedule and estimates of manpower and cost as well as proposals on approaches to joint implementation of the project

Drying Shrinkage Microcracking in Cement-based Materials

NARCIS (Netherlands)

Bisschop, J.; Van Mier, J.G.M.

2002-01-01

In this paper the nature of drying shrinkage microcracking in a variety of model cementbased materials, as well as in more practical types of concrete is described. The model mixtures were studied to elucidate the mechanisms of drying shrinkage microcracking and the factors that influence these

Mesoscopic analysis of drying shrinkage damage in a cementitious material

DEFF Research Database (Denmark)

Moonen, P.; Pedersen, R.R.; Simone, A.

2008-01-01

Concrete and cement-based materials exhibit shrinkage when exposed to drying. Structural effects and inhomogeneity of material properties adverse free shrinkage, hereby inducing stress concentrations and possibly damage. In this contribution, the magnitude of shrinkage- induced damage during...... temperatures are considered: 35 °C and 50 °C. Significantly more micro-damage and higher internal stresses are found for the latter, revealing the importance of drying shrinkage damage, even at laboratory scale....

Computation of shrinkage stresses in prestressed concrete containments

International Nuclear Information System (INIS)

Wu, R.F.; Ouyang, H.

1989-01-01

According to a survey, surface cracking on PCRVs and PCCs under the investigations is confined to drying shrinkage and thermal strain effects and no instances of structurally significant cracking was been found. In this paper, the authors use FEM to compute humidity distribution in drying concrete and shrinkage stresses by internal restraint. Since PCC is built segment by segment in several years, a computational model taking into account construction sequence is presented and shrinkage stresses by external restraints are calculated with the model

Heat shrinkage of electron beam modified EVA

International Nuclear Information System (INIS)

Datta, S.K.; Chaki, T.K.; Bhowmick, A.K.

1997-01-01

Heat shrinkage of electron beam modified ethylene vinyl acetate copolymer (EVA) has been investigated over a range of times, temperatures, stretching, irradiation doses and trimethylolpropane trimethacrylate (TMPTMA) levels. The irradiated (radiation dose 50 kGy and TMPTMA level 1%) and stretched (100% elongation) sample shrinks to a maximum level when kept at 453K temperature for 60 s. The heat shrinkage of samples irradiated with radiation doses of 20, 50, 100 and 150 kGy increases sharply with increasing stretching in the initial stage. Amnesia rating decreases with increasing radiation dose and TMPTMA level as well as gel content. The high radiation dose and TMPTMA level lower the heat shrinkage due to the chain scission. The effect of temperature at which extension is carried out on heat shrinkage is marginal. The irradiated (radiation dose 50 kGy and TMPTMA level 1%) EVA tubes of different dimensions expanded in a laboratory grade tube expander show similar behaviour at 453K and 60 s. The X-ray and DSC studies reveal that the crystallinity increases on stretching due to orientation of chains and it decreases to a considerable extent on heat shrinking. The theoretical and experimental values of heat shrinkage for tubes and rectangular strips are in good accord, when the radiation dose is 50 kGy and TMPTMA level 1%. (author)

Heat shrinkage of electron beam modified EVA

Energy Technology Data Exchange (ETDEWEB)

Datta, S.K.; Chaki, T.K.; Bhowmick, A.K. [Indian Institute of Technology, Kharagpur (India). Rubber Technology Center; Tikku, V.K.; Pradhan, N.K. [NICCO Corporation Ltd., (Cable Div.), Calcutta (India)

1997-10-01

Heat shrinkage of electron beam modified ethylene vinyl acetate copolymer (EVA) has been investigated over a range of times, temperatures, stretching, irradiation doses and trimethylolpropane trimethacrylate (TMPTMA) levels. The irradiated (radiation dose 50 kGy and TMPTMA level 1%) and stretched (100% elongation) sample shrinks to a maximum level when kept at 453K temperature for 60 s. The heat shrinkage of samples irradiated with radiation doses of 20, 50, 100 and 150 kGy increases sharply with increasing stretching in the initial stage. Amnesia rating decreases with increasing radiation dose and TMPTMA level as well as gel content. The high radiation dose and TMPTMA level lower the heat shrinkage due to the chain scission. The effect of temperature at which extension is carried out on heat shrinkage is marginal. The irradiated (radiation dose 50 kGy and TMPTMA level 1%) EVA tubes of different dimensions expanded in a laboratory grade tube expander show similar behaviour at 453K and 60 s. The X-ray and DSC studies reveal that the crystallinity increases on stretching due to orientation of chains and it decreases to a considerable extent on heat shrinking. The theoretical and experimental values of heat shrinkage for tubes and rectangular strips are in good accord, when the radiation dose is 50 kGy and TMPTMA level 1%. (author).

Dry shrinkage characteristics of buffer materials

Energy Technology Data Exchange (ETDEWEB)

Suzuki, H. [ITC, Tokai, Ibaraki (Japan); Fujita, A.

1999-03-01

Generation of cracks due to drying of compressed bentonite was observed by changing the initial water content to obtain shrinkage constants such as shrinkage limit and shrinking rate. As a result, generation of practically no cracks was observed when the initial water content of samples was below 13%. The volume change due to drying increased with the water content in the sample, and the shrinkage constants were found to depend on the initial water content. Further, the one-dimensional compression strength after drying was compared with that before drying in order to clarify the effect of cracks generated by drying on the mechanical strength. As a result, the dry sample with cracks proved to have large one-dimensional compression strength or E{sub 50} compared to wet samples, so that the mechanical strength was kept even after drying. (H. Baba)

Predicting shrinkage and warpage in injection molding: Towards automatized mold design

Science.gov (United States)

Zwicke, Florian; Behr, Marek; Elgeti, Stefanie

2017-10-01

It is an inevitable part of any plastics molding process that the material undergoes some shrinkage during solidification. Mainly due to unavoidable inhomogeneities in the cooling process, the overall shrinkage cannot be assumed as homogeneous in all volumetric directions. The direct consequence is warpage. The accurate prediction of such shrinkage and warpage effects has been the subject of a considerable amount of research, but it is important to note that this behavior depends greatly on the type of material that is used as well as the process details. Without limiting ourselves to any specific properties of certain materials or process designs, we aim to develop a method for the automatized design of a mold cavity that will produce correctly shaped moldings after solidification. Essentially, this can be stated as a shape optimization problem, where the cavity shape is optimized to fulfill some objective function that measures defects in the molding shape. In order to be able to develop and evaluate such a method, we first require simulation methods for the diffierent steps involved in the injection molding process that can represent the phenomena responsible for shrinkage and warpage ina sufficiently accurate manner. As a starting point, we consider the solidification of purely amorphous materials. In this case, the material slowly transitions from fluid-like to solid-like behavior as it cools down. This behavior is modeled using adjusted viscoelastic material models. Once the material has passed a certain temperature threshold during cooling, any viscous effects are neglected and the behavior is assumed to be fully elastic. Non-linear elastic laws are used to predict shrinkage and warpage that occur after this point. We will present the current state of these simulation methods and show some first approaches towards optimizing the mold cavity shape based on these methods.

ITER safety

International Nuclear Information System (INIS)

Raeder, J.; Piet, S.; Buende, R.

1991-01-01

As part of the series of publications by the IAEA that summarize the results of the Conceptual Design Activities for the ITER project, this document describes the ITER safety analyses. It contains an assessment of normal operation effluents, accident scenarios, plasma chamber safety, tritium system safety, magnet system safety, external loss of coolant and coolant flow problems, and a waste management assessment, while it describes the implementation of the safety approach for ITER. The document ends with a list of major conclusions, a set of topical remarks on technical safety issues, and recommendations for the Engineering Design Activities, safety considerations for siting ITER, and recommendations with regard to the safety issues for the R and D for ITER. Refs, figs and tabs

A multiresolution approach to iterative reconstruction algorithms in X-ray computed tomography.

Science.gov (United States)

De Witte, Yoni; Vlassenbroeck, Jelle; Van Hoorebeke, Luc

2010-09-01

In computed tomography, the application of iterative reconstruction methods in practical situations is impeded by their high computational demands. Especially in high resolution X-ray computed tomography, where reconstruction volumes contain a high number of volume elements (several giga voxels), this computational burden prevents their actual breakthrough. Besides the large amount of calculations, iterative algorithms require the entire volume to be kept in memory during reconstruction, which quickly becomes cumbersome for large data sets. To overcome this obstacle, we present a novel multiresolution reconstruction, which greatly reduces the required amount of memory without significantly affecting the reconstructed image quality. It is shown that, combined with an efficient implementation on a graphical processing unit, the multiresolution approach enables the application of iterative algorithms in the reconstruction of large volumes at an acceptable speed using only limited resources.

Drying shrinkage problems in high PI subgrade soils.

Science.gov (United States)

2014-01-01

The main objective of this study was to investigate the longitudinal cracking in pavements due to drying : shrinkage of high PI subgrade soils. The study involved laboartory soil testing and modeling. The : shrinkage cracks usually occur within the v...

Variation of Shrinkage Strain within the Depth of Concrete Beams

Directory of Open Access Journals (Sweden)

Jong-Hyun Jeong

2015-11-01

Full Text Available The variation of shrinkage strain within beam depth was examined through four series of time-dependent laboratory experiments on unreinforced concrete beam specimens. Two types of beam specimens, horizontally cast and vertically cast, were tested; shrinkage variation was observed in the horizontally cast specimens. This indicated that the shrinkage variation within the beam depth was due to water bleeding and tamping during the placement of the fresh concrete. Shrinkage strains were measured within the beam depth by two types of strain gages, surface-attached and embedded. The shrinkage strain distribution within the beam depth showed a consistent tendency for the two types of gages. The test beams were cut into four sections after completion of the test, and the cutting planes were divided into four equal sub-areas to measure the aggregate concentration for each sub-area of the cutting plane. The aggregate concentration increased towards the bottom of the beam. The shrinkage strain distribution was estimated by Hobbs’ equation, which accounts for the change of aggregate volume concentration.

Volume change of limestone and its effects on drying shrinkage of concrete

OpenAIRE

YAGI, Shogo; AQUINO, Carlos; INOUE, Masumi; OKAMOTO, Takahisa

2010-01-01

Recently, the cracks of concrete by drying shrinkage become one of the problems in the construction industry in Japan. The drying shrinkage decreases when the concrete is produced with limestone aggregate. However, it is not clear why the drying shrinkage is decreased. The purpose of this study is to clarify the relation between the drying shrinkage of concrete and the limestone aggregate. In this study, the experiments about the strength, elasticity and drying shrinkage of concrete and the p...

Numerical simulation of early-age shrinkage effects on RC member deflections and cracking development

Directory of Open Access Journals (Sweden)

P. Bernardi

2016-07-01

Full Text Available Shrinkage effects on short-term behavior of reinforced concrete elements are often neglected both in design code provisions and in numerical simulations. However, it is known that their influence on serviceability performance can be significant, especially in case of lightly-reinforced beams. As a matter of fact, the restraint provided by the reinforcement on concrete determines a reduction of the cracking load of the structural element, as well as an increase of its deflection. This paper deals with the modeling of early-age shrinkage effects in the field of smeared crack approaches. To this aim, an existing non-linear constitutive relation for cracked reinforced concrete elements is extended herein to include early-age concrete shrinkage. Careful verifications of the model are carried out by comparing numerical results with significant experimental data reported in technical literature, providing a good agreement both in terms of global and local behavior.

Creep and shrinkage of concrete according to Eurocode 2

Directory of Open Access Journals (Sweden)

Milićević Ivan M.

2017-01-01

Full Text Available This paper presents the procedure for calculation of creep coefficient and shrinkage strain according to Eurocode 2 (SRPS EN 1992-1-1:2004. The calculated values of final creep coefficient and shrinkage strain, for the usual design conditions, are given in Annexes. The influence of key parameters on final creep coefficient and shrinkage strain is analyzed and the comparison between their final values calculated according to Eurocode 2 and BAB 87 is presented.

An Iterated Tabu Search Approach for the Clique Partitioning Problem

Directory of Open Access Journals (Sweden)

Gintaras Palubeckis

2014-01-01

all cliques induced by the subsets is as small as possible. We develop an iterated tabu search (ITS algorithm for solving this problem. The proposed algorithm incorporates tabu search, local search, and solution perturbation procedures. We report computational results on CPP instances of size up to 2000 vertices. Performance comparisons of ITS against state-of-the-art methods from the literature demonstrate the competitiveness of our approach.

Reduction of the Early Autogenous Shrinkage of High Strength Concrete

Directory of Open Access Journals (Sweden)

Drago Saje

2015-01-01

Full Text Available The results of a laboratory investigation on the early autogenous shrinkage of high strength concrete, and the possibilities of its reduction, are presented. Such concrete demonstrates significant autogenous shrinkage, which should, however, be limited in the early stages of its development in order to prevent the occurrence of cracks and/or drop in the load-carrying capacity of concrete structures. The following possibilities for reducing autogenous shrinkage were investigated: the use of low-heat cement, a shrinkage-reducing admixture, steel fibres, premoistened polypropylene fibres, and presoaked lightweight aggregate. In the case of the use of presoaked natural lightweight aggregate, with a fraction from 2 to 4 mm, the early autogenous shrinkage of one-day-old high strength concrete decreased by about 90%, with no change to the concrete's compressive strength in comparison with that of the reference concrete.

Evaluation of polymerization shrinkage, polymerization shrinkage stress, wear resistance, and compressive strength of a silorane-based composite: A finite element analysis study

Directory of Open Access Journals (Sweden)

Suresh Mitthra

2017-01-01

Full Text Available Background: Understanding the mechanical properties is important in predicting the clinical behavior of composites. Finite element analysis (FEA evaluates properties of materials replicating clinical scenario. Aim: This study evaluated polymerization shrinkage and stress, wear resistance (WR, and compressive strength (CS of silorane in comparison with two methacrylate resins. Settings and Design: This study design was a numerical study using FEA. Materials and Methods: Three-dimensional (3D models of maxillary premolar with Class I cavities (2 mm depth, 4 mm length, and 2.5 mm width created and restored with silorane, nanohybrid, and microhybrid; Groups I, II, and III, respectively. Loads of 200–600 N were applied. Polymerization shrinkage was first determined by displacement produced in the X, Y, and Z planes. Maximum stress distribution due to shrinkage was calculated using AN SYS software. 3D cube models of composite resins were simulated with varying filler particle size. Similar loads were applied. WR and compressive stress were calculated: K W L/H and load/cross-sectional area, respectively. Statistical analysis done using one-way ANOVA, Kruskal–Wallis, and Tukey's honestly significant difference test (P < 0.05. Results: Polymerization shrinkage (0.99% and shrinkage stress (233.21 Mpa of silorane were less compared to microhybrid (2.14% and 472.43 Mpa and nanohybrid (2.32% and 464.88 Mpa. Silorane (7.92×/1011 μm/mm3 and nanohybrid (7.79×/1011 showed superior WR than microhybrid (1.113×/1017. There was no significant difference in compressive stress among the groups. Conclusion: Silorane exhibited less polymerization shrinkage and shrinkage stress compared to methacrylates. Silorane and nanohybrid showed greater WR compared to microhybrid. CS of all groups was similar.

Influence of length-to-diameter ratio on shrinkage of basalt fiber concrete

Science.gov (United States)

Ruijie, MA; Yang, Jiansen; Liu, Yuan; Zheng, Xiaojun

2017-09-01

In order to study the shrinkage performance of basalt concrete, using the shrinkage rate as index, the work not only studied the influence of different length-to-diameter ratio (LDR) on plastic shrinkage and drying shrinkage of basalt fiber concrete, but also analyzed the action mechanism. The results show that when the fiber content is 0.1%, the LDR of 800 and 1200 take better effects on reducing plastic shrinkage, however the fiber content is 0.3%, that of LDR 600 is better. To improve drying shrinkage, the fiber of LDR 800 takes best effect. In the concrete structure, the adding basalt fibers form a uniform and chaotic supporting system, optimize the pore and the void structure of concrete, make the material further compacted, reduce the water loss, so as to decrease the shrinkage of concrete effectively.

Volumetric polymerization shrinkage of contemporary composite resins

OpenAIRE

Nagem Filho, Halim; Nagem, Haline Drumond; Francisconi, Paulo Afonso Silveira; Franco, Eduardo Batista; Mondelli, Rafael Francisco Lia; Coutinho, Kennedy Queiroz

2007-01-01

The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill ...

Shrinkage Module of Soil Samples with Different Cement Content

Directory of Open Access Journals (Sweden)

Mohannad Sabry

2017-12-01

Full Text Available The differences in soil's body mass during shrinkage over time have changes in soil physical properties which provide an important reason to check the design of underground foundations in expansive soils. In this paper, a state-of-art of the soil heat stress-strain relationship prediction methods is checked using soil engineering laboratory experiments and Matlab R2013b numerical modelling. The shrinkage of soils with different cement content of (0%, 2%, 4%, 6% and 8% with the same water content of 20 percent in room temperature for 24 hours, are critically reviewed in terms of their predictive shrinkage along with their strengths and flexural behaviour. The review highlights the prediction methods present to determine the effect of heat stress on the shrinkage of soil samples with different cement content after classifying the soils into clay, silt and sand depending on their particle size using sieve and hydrometer experiments. The results of the soil engineering laboratory experiments showed that as the cement content increases, the shrinkage of soil decreases as a result of increased elasticity in soil. The numerical analysis using finite element method in Matlab R2013b shows that as the cement content increases the displacement in the soil sample decreases and that the soil sample with 8% cement content has more resistance to shrinkage and less displacement than the soil with 6% cement, which has less resistance to heat stresses and more displacement.

Creep and shrinkage analysis for concrete spent fuel dry storage module

Energy Technology Data Exchange (ETDEWEB)

Zhang, D. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)], E-mail: zhangd@aecl.ca

2009-07-01

CANDU reactors are designed in Canada and are built and operated worldwide to produce electricity economically with no emission of green house gases. This paper presents creep and shrinkage analysis for a concrete spent fuel dry storage module of a CANDU nuclear power plant. Creep and shrinkage analysis was performed using a method outlined in American Concrete Institute (ACI) code, and then the creep and shrinkage strains were analyzed in a finite element model to obtain the structural behavior of the concrete module. This demonstrated that the creep and shrinkage analysis for concrete spent fuel dry storage is reasonable. AECL's spent fuel dry storage module is adequate to resist the time-dependent effects due to creep and shrinkage of concrete. (author)

Creep and shrinkage analysis for concrete spent fuel dry storage module

International Nuclear Information System (INIS)

Zhang, D.

2009-01-01

CANDU reactors are designed in Canada and are built and operated worldwide to produce electricity economically with no emission of green house gases. This paper presents creep and shrinkage analysis for a concrete spent fuel dry storage module of a CANDU nuclear power plant. Creep and shrinkage analysis was performed using a method outlined in American Concrete Institute (ACI) code, and then the creep and shrinkage strains were analyzed in a finite element model to obtain the structural behavior of the concrete module. This demonstrated that the creep and shrinkage analysis for concrete spent fuel dry storage is reasonable. AECL's spent fuel dry storage module is adequate to resist the time-dependent effects due to creep and shrinkage of concrete. (author)

Measuring method for heat-shrinkage of fuel pellet

International Nuclear Information System (INIS)

Komono, Akira; Ishizaki, Jin; Inaki, Kiyohiro.

1997-01-01

The present invention concerns a method of determining an amount of heat-shrinkage of UR 2 pellets containing gadolinium oxide (Gd 2 O 2 ) based on the difference of the density thereof before and after heating. In a heat shrinkage test of UO 2 pellets containing from 1.0 to 15.0% by weight of gadolinium oxide, the amount of heat-shrinkage is measured under the condition of heat-retaining temperature: from 1700 to 1750degC, temperature elevation time and lowering time: from 90 to 120mins, heat-retaining time: 24hours, inert gas atmosphere, gas pressure: 0.35kg/cm 2 and gas dew point: from -55 to 40degC without changing O/M. This invention has a feature in the use of the inert gas and the elevation of the dew point of the gas. Then, oxygen dissociation phenomenon from crystal lattices of the fuel pellets is suppressed, and normal densification value is shown. Then, fuel pellets of good quality with less fluctuation of the heat-shrinkage can be obtained. (N.H.)

Towards Automated Binding Affinity Prediction Using an Iterative Linear Interaction Energy Approach

Directory of Open Access Journals (Sweden)

C. Ruben Vosmeer

2014-01-01

Full Text Available Binding affinity prediction of potential drugs to target and off-target proteins is an essential asset in drug development. These predictions require the calculation of binding free energies. In such calculations, it is a major challenge to properly account for both the dynamic nature of the protein and the possible variety of ligand-binding orientations, while keeping computational costs tractable. Recently, an iterative Linear Interaction Energy (LIE approach was introduced, in which results from multiple simulations of a protein-ligand complex are combined into a single binding free energy using a Boltzmann weighting-based scheme. This method was shown to reach experimental accuracy for flexible proteins while retaining the computational efficiency of the general LIE approach. Here, we show that the iterative LIE approach can be used to predict binding affinities in an automated way. A workflow was designed using preselected protein conformations, automated ligand docking and clustering, and a (semi-automated molecular dynamics simulation setup. We show that using this workflow, binding affinities of aryloxypropanolamines to the malleable Cytochrome P450 2D6 enzyme can be predicted without a priori knowledge of dominant protein-ligand conformations. In addition, we provide an outlook for an approach to assess the quality of the LIE predictions, based on simulation outcomes only.

Linear Shrinkage Behaviour of Compacted Loam Masonry Blocks

Directory of Open Access Journals (Sweden)

NAWAB ALI LAKHO

2017-04-01

Full Text Available Walls of wet loam, used in earthen houses, generally experience more shrinkage which results in cracks and less compressive strength. This paper presents a technique of producing loam masonry blocks that are compacted in drained state during casting process in order to minimize shrinkage. For this purpose, loam masonry blocks were cast and compacted at a pressure of 6 MPa and then dried in shade by covering them in plastic sheet. The results show that linear shrinkage of 2% occurred which is smaller when compared to un-compacted wet loam walls. This implies that the loam masonry blocks compacted in drained state is expected to perform better than un-compacted wet loam walls.

Shrinkage measurement for holographic recording materials

Science.gov (United States)

Fernández, R.; Gallego, S.; Márquez, A.; Francés, J.; Navarro Fuster, V.; Neipp, C.; Ortuño, M.; Beléndez, A.; Pascual, I.

2017-05-01

There is an increasing demand for new holographic recording materials. One of them are photopolymers, which are becoming a classic media in this field. Their versatility is well known and new possibilities are being created by including new components, such as nanoparticles or dispersed liquid crystal molecules in classical formulations, making them interesting for additional applications in which the thin film preparation and the structural modification have a fundamental importance. Prior to obtaining a wide commercialization of displays based on photopolymers, one of the key aspects is to achieve a complete characterization of them. In this sense, one of the main parameters to estimate and control is the shrinkage of these materials. The volume variations change the angular response of the hologram in two aspects, the angular selectivity and the maximum diffraction efficiency. One criteria for the recording material to be used in a holographic data storage application is the shrinkage, maximum of 0.5%. Along this work, we compare two different methods to measure the holographic recording material shrinkage. The first one is measuring the angle of propagation for both diffracted orders +/-1 when slanted gratings are recorded, so that an accurate value of the grating vector can be calculated. The second one is based on interference measurements at zero spatial frequency limit. We calculate the shrinkage for three different photopolymers: a polyvinyl alcohol acrylamide (PVA/AA) based photopolymer, one of the greenest photopolymers whose patent belongs to the Alicante University called Biophotopol and on the last place a holographic-dispersed liquid crystal photopolymer (H-PDLC).

Effect of shrinkage porosity on mechanical properties of ferritic ductile iron

Directory of Open Access Journals (Sweden)

Wang Zehua

2013-05-01

Full Text Available Casting defects could largely affect the mechanical properties of casting products. A number of test pieces made of ductile iron (EN-GJS-400-18-LT with different levels of shrinkage porosity were prepared and then tensile and fatigue tests were performed to investigate the impact of shrinkage porosity on their mechanical properties. The results showed that the tensile strength decreases linearly with increasing of the shrinkage porosity. The tensile elongation decreases sharply with the increase of the shrinkage porosity mainly due to the non-uniform plastic deformation. The fatigue life also dramatically declines with increasing of the porosity and follows a power law relationship with the area percentage of porosity. The existence of the shrinkage porosity made the fatigue fracture complex. The shrinkage pores, especially those close to the surface usually became the crack initiation sites. For test pieces with less porosity, the fatigue fracture was clearly composed of crack initiation, propagation, and overloading. While for samples with high level of porosity, multiple crack initiation sites were observed.

Effect of temperature and humidity on post-gel shrinkage, cusp deformation, bond strength and shrinkage stress - Construction of a chamber to simulate the oral environment.

Science.gov (United States)

Bicalho, Aline Aredes; de Souza, Silas Júnior Boaventura; de Rosatto, Camila Maria Peres; Tantbirojn, Daranee; Versluis, Antheunis; Soares, Carlos José

2015-12-01

Evaluate the effect of environment on post-gel shrinkage (Shr), cuspal strains (CS), microtensile bond strength (μTBS), elastic modulus (E) and shrinkage stress in molars with large class II restorations. Sixty human molars received standardized Class II mesio-oclusal-distal cavity preparations. Restorations were made with two composites (CHA, Charisma Diamond, Heraus Kulzer and IPS Empress Direct, Ivoclar-Vivadent) using three environment conditions (22°C/50% humidity, 37°C/50% humidity and 37°C/90% humidity) simulated in custom developed chamber. Shr was measured using the strain gauge technique (n=10). CS was measured using strain gauges. Half of the teeth (n=5) were used to assess the elastic modulus (E) and Knoop hardness (KHN) at different depths using microhardness indentation. The other half (n=5) was used to measure the μTBS. The composites and environment conditions were simulated in a two-dimensional finite element analysis of a tooth restoration. Polymerization shrinkage was modeled using Shr data. The Shr, CS, μTBS, KHN and E data were statistically analyzed using two-way ANOVA and Tukey test (significance level: 0.05). Both composites had similar Shr, CS, μTBS and shrinkage stress. CHA had higher elastic modulus than IPS. Increasing temperature and humidity significantly increased Shr, CS and shrinkage stress. μTBS were similar for groups with lower humidity, irrespective of temperature, and higher with higher humidity. E and KHN were constant through the depth for CHA. E and KHN values were affected by environment only for IPS, mainly deeper in the cavity. Shrinkage stress at dentin/composite interface had high inverse correlation with μTBS. Shrinkage stress in enamel had high correlation with CS. Increasing temperature and humidity caused higher post-gel shrinkage and cusp deformation with higher shrinkage stresses in the tooth structure and tooth/restoration interface for both composites tested. The chamber developed for simulating the

Creep and Shrinkage of High Strength Concretes: an Experimental Analysis

Directory of Open Access Journals (Sweden)

Berenice Martins Toralles carbonari

2002-01-01

Full Text Available The creep and shrinkage behaviour of high strength silica fume concretes is significantly different from that of conventional concretes. In order to represent the proper time-dependent response of the material in structural analysis and design, these aspects should be adequately quantified. This paper discusses an experimental setup that is able to determine the creep and shrinkage of concrete from the time of placing. It also compares different gages that can be used for measuring the strains. The method is applied to five different concretes in the laboratory under controlled environmental conditions. The phenomena that are quantified can be classified as basic shrinkage, drying shrinkage, basic creep and drying creep. The relative importance of these mechanisms in high strength concrete will also be presented.

Comparison of shrinkage related properties of various patch repair materials

Science.gov (United States)

Kristiawan, S. A.; Fitrianto, R. S.

2017-02-01

A patch repair material has been developed in the form of unsaturated polyester resin (UPR)-mortar. The performance and durability of this material are governed by its compatibility with the concrete being repaired. One of the compatibility issue that should be tackled is the dimensional compatibility as a result of differential shrinkage between the repair material and the concrete substrate. This research aims to evaluate such shrinkage related properties of UPR-mortar and to compare with those of other patch repair materials. The investigation includes the following aspects: free shrinkage, resistance to delamination and cracking. The results indicate that UPR-mortar poses a lower free shrinkage, lower risk of both delamination and cracking tendency in comparison to other repair materials.

Geosynthetic clay liners shrinkage under simulated daily thermal cycles.

Science.gov (United States)

Sarabadani, Hamid; Rayhani, Mohammad T

2014-06-01

Geosynthetic clay liners are used as part of composite liner systems in municipal solid waste landfills and other applications to restrict the escape of contaminants into the surrounding environment. This is attainable provided that the geosynthetic clay liner panels continuously cover the subsoil. Previous case histories, however, have shown that some geosynthetic clay liner panels are prone to significant shrinkage and separation when an overlying geomembrane is exposed to solar radiation. Experimental models were initiated to evaluate the potential shrinkage of different geosynthetic clay liner products placed over sand and clay subsoils, subjected to simulated daily thermal cycles (60°C for 8 hours and 22°C for 16 hours) modelling field conditions in which the liner is exposed to solar radiation. The variation of geosynthetic clay liner shrinkage was evaluated at specified times by a photogrammetry technique. The manufacturing techniques, the initial moisture content, and the aspect ratio (ratio of length to width) of the geosynthetic clay liner were found to considerably affect the shrinkage of geosynthetic clay liners. The particle size distribution of the subsoil and the associated suction at the geosynthetic clay liner-subsoil interface was also found to have significant effects on the shrinkage of the geosynthetic clay liner. © The Author(s) 2014.

Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete

Directory of Open Access Journals (Sweden)

Ashkan Saradar

2018-02-01

Full Text Available Concrete shrinkage and volume reduction happens due to the loss of moisture, which eventually results in cracks and more concrete deformation. In this study, the effect of polypropylene (PP, steel, glass, basalt, and polyolefin fibers on compressive and flexural strength, drying shrinkage, and cracking potential, using the ring test at early ages of high-strength concrete mixtures, was investigated. The restrained shrinkage test was performed on concrete ring specimens according to the ASTM C1581 standard. The crack width and age of restrained shrinkage cracking were the main parameters studied in this research. The results indicated that the addition of fiber increases the compressive strength by 16%, 20%, and 3% at the age of 3, 7, and 28 days, respectively, and increases the flexural toughness index up to 7.7 times. Steel and glass fibers had a better performance in flexural strength, but relatively poor action in the velocity reduction and cracking time of the restrained shrinkage. Additionally, cracks in all concrete ring specimens except for the polypropylene-containing mixture, was developed to a full depth crack. The mixture with polypropylene fiber indicated a reduction in crack width up to 62% and an increasing age cracking up to 84%.

Autogenous shrinkage in high-performance cement paste: An evaluation of basic mechanisms

International Nuclear Information System (INIS)

Lura, Pietro; Jensen, Ole Mejlhede; Breugel, Klaas van

2003-01-01

In this paper, various mechanisms suggested to cause autogenous shrinkage are presented. The mechanisms are evaluated from the point of view of their soundness and applicability to quantitative modeling of autogenous shrinkage. The capillary tension approach is advantageous, because it has a sound mechanical and thermodynamical basis. Furthermore, this mechanism is easily applicable in a numerical model when dealing with a continuously changing microstructure. In order to test the numerical model, autogenous deformation and internal relative humidity (RH) of a Portland cement paste were measured during the first week of hardening. The isothermal heat evolution was also recorded to monitor the progress of hydration and the elastic modulus in compression was measured. RH change, degree of hydration and elastic modulus were used as input data for the calculation of autogenous deformation based on the capillary tension approach. Because a part of the RH drop in the cement paste is due to dissolved salts in the pore solution, a method is suggested to separate this effect from self-desiccation and to calculate the actual stress in the pore fluid associated with menisci formation

Exploiting tumor shrinkage through temporal optimization of radiotherapy

International Nuclear Information System (INIS)

Unkelbach, Jan; Craft, David; Hong, Theodore; Papp, Dávid; Wolfgang, John; Bortfeld, Thomas; Ramakrishnan, Jagdish; Salari, Ehsan

2014-01-01

In multi-stage radiotherapy, a patient is treated in several stages separated by weeks or months. This regimen has been motivated mostly by radiobiological considerations, but also provides an approach to reduce normal tissue dose by exploiting tumor shrinkage. The paper considers the optimal design of multi-stage treatments, motivated by the clinical management of large liver tumors for which normal liver dose constraints prohibit the administration of an ablative radiation dose in a single treatment. We introduce a dynamic tumor model that incorporates three factors: radiation induced cell kill, tumor shrinkage, and tumor cell repopulation. The design of multi-stage radiotherapy is formulated as a mathematical optimization problem in which the total dose to the normal tissue is minimized, subject to delivering the prescribed dose to the tumor. Based on the model, we gain insight into the optimal administration of radiation over time, i.e. the optimal treatment gaps and dose levels. We analyze treatments consisting of two stages in detail. The analysis confirms the intuition that the second stage should be delivered just before the tumor size reaches a minimum and repopulation overcompensates shrinking. Furthermore, it was found that, for a large range of model parameters, approximately one-third of the dose should be delivered in the first stage. The projected benefit of multi-stage treatments in terms of normal tissue sparing depends on model assumptions. However, the model predicts large dose reductions by more than a factor of 2 for plausible model parameters. The analysis of the tumor model suggests that substantial reduction in normal tissue dose can be achieved by exploiting tumor shrinkage via an optimal design of multi-stage treatments. This suggests taking a fresh look at multi-stage radiotherapy for selected disease sites where substantial tumor regression translates into reduced target volumes. (paper)

Shrinkage deformation of cement foam concrete

Science.gov (United States)

Kudyakov, A. I.; Steshenko, A. B.

2015-01-01

The article presents the results of research of dispersion-reinforced cement foam concrete with chrysotile asbestos fibers. The goal was to study the patterns of influence of chrysotile asbestos fibers on drying shrinkage deformation of cement foam concrete of natural hardening. The chrysotile asbestos fiber contains cylindrical fiber shaped particles with a diameter of 0.55 micron to 8 microns, which are composed of nanostructures of the same form with diameters up to 55 nm and length up to 22 microns. Taking into account the wall thickness, effective reinforcement can be achieved only by microtube foam materials, the so- called carbon nanotubes, the dimensions of which are of power less that the wall pore diameter. The presence of not reinforced foam concrete pores with perforated walls causes a decrease in its strength, decreases the mechanical properties of the investigated material and increases its shrinkage. The microstructure investigation results have shown that introduction of chrysotile asbestos fibers in an amount of 2 % by weight of cement provides the finely porous foam concrete structure with more uniform size closed pores, which are uniformly distributed over the volume. This reduces the shrinkage deformation of foam concrete by 50%.

Density control in ITER: an iterative learning control and robust control approach

Science.gov (United States)

Ravensbergen, T.; de Vries, P. C.; Felici, F.; Blanken, T. C.; Nouailletas, R.; Zabeo, L.

2018-01-01

Plasma density control for next generation tokamaks, such as ITER, is challenging because of multiple reasons. The response of the usual gas valve actuators in future, larger fusion devices, might be too slow for feedback control. Both pellet fuelling and the use of feedforward-based control may help to solve this problem. Also, tight density limits arise during ramp-up, due to operational limits related to divertor detachment and radiative collapses. As the number of shots available for controller tuning will be limited in ITER, in this paper, iterative learning control (ILC) is proposed to determine optimal feedforward actuator inputs based on tracking errors, obtained in previous shots. This control method can take the actuator and density limits into account and can deal with large actuator delays. However, a purely feedforward-based density control may not be sufficient due to the presence of disturbances and shot-to-shot differences. Therefore, robust control synthesis is used to construct a robustly stabilizing feedback controller. In simulations, it is shown that this combined controller strategy is able to achieve good tracking performance in the presence of shot-to-shot differences, tight constraints, and model mismatches.

Direct voxel-based comparisons between grey matter shrinkage and glucose hypometabolism in chronic alcoholism.

Science.gov (United States)

Ritz, Ludivine; Segobin, Shailendra; Lannuzel, Coralie; Boudehent, Céline; Vabret, François; Eustache, Francis; Beaunieux, Hélène; Pitel, Anne L

2016-09-01

Alcoholism is associated with widespread brain structural abnormalities affecting mainly the frontocerebellar and the Papez's circuits. Brain glucose metabolism has received limited attention, and few studies used regions of interest approach and showed reduced global brain metabolism predominantly in the frontal and parietal lobes. Even though these studies have examined the relationship between grey matter shrinkage and hypometabolism, none has performed a direct voxel-by-voxel comparison between the degrees of structural and metabolic abnormalities. Seventeen alcoholic patients and 16 control subjects underwent both structural magnetic resonance imaging and (18)F-2-fluoro-deoxy-glucose-positron emission tomography examinations. Structural abnormalities and hypometabolism were examined in alcoholic patients compared with control subjects using two-sample t-tests. Then, these two patterns of brain damage were directly compared with a paired t-test. Compared to controls, alcoholic patients had grey matter shrinkage and hypometabolism in the fronto-cerebellar circuit and several nodes of Papez's circuit. The direct comparison revealed greater shrinkage than hypometabolism in the cerebellum, cingulate cortex, thalamus and hippocampus and parahippocampal gyrus. Conversely, hypometabolism was more severe than shrinkage in the dorsolateral, premotor and parietal cortices. The distinct profiles of abnormalities found within the Papez's circuit, the fronto-cerebellar circuit and the parietal gyrus in chronic alcoholism suggest the involvement of different pathological mechanisms. © The Author(s) 2015.

Estimation of the profile of cross-machine shrinkage of paper

International Nuclear Information System (INIS)

I'Anson, S J; Sampson, W W; Constantino, R P A; Hoole, S M

2008-01-01

In common with many other materials, paper tends to shrink as it dries. Although every attempt is made to restrain paper, some shrinkage occurs on all paper machines in the direction perpendicular to that of manufacture and this shrinkage is always much higher at the edges of the machine than in the centre. Measurement of the profile of this cross-machine shrinkage is possible using the fast Fourier transform to locate and measure periodic elements imprinted by the filtration fabrics used during the formation of the paper web. This paper describes a new method which allows the geometrical relationships within the fabric to be used along with dimensional changes to estimate shrinkage. The method has the advantages over previous methods of more tolerant sampling protocols, operator independent analysis and improved accuracy

Shrinkage calibration method for μPIM manufactured parts

DEFF Research Database (Denmark)

Quagliotti, Danilo; Tosello, Guido; Salaga, J.

2016-01-01

Five green and five sintered parts of a micro mechanical component, produced by micro powder injection moulding, were measured using an optical coordinate measuring machine. The aim was to establish a method for quality assurance of the final produced parts. Initially, the so called “green” parts...... were compared with the sintered parts (final products) calculating the percentage of shrinkage after sintering. Successively, the expanded uncertainty of the measured dimensions were evaluated for each single part as well as for the overall parts. Finally, the estimated uncertainty for the shrinkage...... was evaluated propagating the expanded uncertainty previously stated and considering green and sintered parts correlated. Results showed that the proposed method can be effective instating tolerances if it is assumed that the variability on the dimensions induced by the shrinkage equals the propagated expanded...

Development and Performance Assessment of the High-Performance Shrinkage Reducing Agent for Concrete

Directory of Open Access Journals (Sweden)

Hyung Sub Han

2016-01-01

Full Text Available To develop a high-performance shrinkage reducing agent, this study investigated several shrinkage reducing materials and supplements for those materials. Fluidity and air content were satisfactory for the various shrinkage reducing materials. The decrease in viscosity was the lowest for glycol-based materials. The decrease in drying shrinkage was most prominent for mixtures containing glycol-based materials. In particular, mixtures containing G2 achieved a 40% decrease in the amount of drying shrinkage. Most shrinkage reducing materials had weaker level of compressive strength than that of the plain mixture. When 3% triethanolamine was used for early strength improvement, the strength was enhanced by 158% compared to that of the plain mixture on day 1; enhancement values were 135% on day 7 and 113% on day 28. To assess the performance of the developed high-performance shrinkage reducing agent and to determine the optimal amount, 2.0% shrinkage reducing agent was set as 40% of the value of the plain mixture. While the effect was more prominent at higher amounts, to prevent deterioration of the compressive strength and the other physical properties, the recommended amount is less than 2.0%.

Further Evaluation of Covariate Analysis using Empirical Bayes Estimates in Population Pharmacokinetics: the Perception of Shrinkage and Likelihood Ratio Test.

Science.gov (United States)

Xu, Xu Steven; Yuan, Min; Yang, Haitao; Feng, Yan; Xu, Jinfeng; Pinheiro, Jose

2017-01-01

Covariate analysis based on population pharmacokinetics (PPK) is used to identify clinically relevant factors. The likelihood ratio test (LRT) based on nonlinear mixed effect model fits is currently recommended for covariate identification, whereas individual empirical Bayesian estimates (EBEs) are considered unreliable due to the presence of shrinkage. The objectives of this research were to investigate the type I error for LRT and EBE approaches, to confirm the similarity of power between the LRT and EBE approaches from a previous report and to explore the influence of shrinkage on LRT and EBE inferences. Using an oral one-compartment PK model with a single covariate impacting on clearance, we conducted a wide range of simulations according to a two-way factorial design. The results revealed that the EBE-based regression not only provided almost identical power for detecting a covariate effect, but also controlled the false positive rate better than the LRT approach. Shrinkage of EBEs is likely not the root cause for decrease in power or inflated false positive rate although the size of the covariate effect tends to be underestimated at high shrinkage. In summary, contrary to the current recommendations, EBEs may be a better choice for statistical tests in PPK covariate analysis compared to LRT. We proposed a three-step covariate modeling approach for population PK analysis to utilize the advantages of EBEs while overcoming their shortcomings, which allows not only markedly reducing the run time for population PK analysis, but also providing more accurate covariate tests.

Polymerization shrinkage stress of composite resins and resin cements - What do we need to know?

Science.gov (United States)

Soares, Carlos José; Faria-E-Silva, André Luis; Rodrigues, Monise de Paula; Vilela, Andomar Bruno Fernandes; Pfeifer, Carmem Silvia; Tantbirojn, Daranee; Versluis, Antheunis

2017-08-28

Polymerization shrinkage stress of resin-based materials have been related to several unwanted clinical consequences, such as enamel crack propagation, cusp deflection, marginal and internal gaps, and decreased bond strength. Despite the absence of strong evidence relating polymerization shrinkage to secondary caries or fracture of posterior teeth, shrinkage stress has been associated with post-operative sensitivity and marginal stain. The latter is often erroneously used as a criterion for replacement of composite restorations. Therefore, an indirect correlation can emerge between shrinkage stress and the longevity of composite restorations or resin-bonded ceramic restorations. The relationship between shrinkage and stress can be best studied in laboratory experiments and a combination of various methodologies. The objective of this review article is to discuss the concept and consequences of polymerization shrinkage and shrinkage stress of composite resins and resin cements. Literature relating to polymerization shrinkage and shrinkage stress generation, research methodologies, and contributing factors are selected and reviewed. Clinical techniques that could reduce shrinkage stress and new developments on low-shrink dental materials are also discussed.

Characterisation of tissue shrinkage during microwave thermal ablation.

Science.gov (United States)

Farina, Laura; Weiss, Noam; Nissenbaum, Yitzhak; Cavagnaro, Marta; Lopresto, Vanni; Pinto, Rosanna; Tosoratti, Nevio; Amabile, Claudio; Cassarino, Simone; Goldberg, S Nahum

2014-11-01

The aim of this study was to characterise changes in tissue volume during image-guided microwave ablation in order to arrive at a more precise determination of the true ablation zone. The effect of power (20-80 W) and time (1-10 min) on microwave-induced tissue contraction was experimentally evaluated in various-sized cubes of ex vivo liver (10-40 mm ± 2 mm) and muscle (20 and 40 mm ± 2 mm) embedded in agar phantoms (N = 119). Post-ablation linear and volumetric dimensions of the tissue cubes were measured and compared with pre-ablation dimensions. Subsequently, the process of tissue contraction was investigated dynamically during the ablation procedure through real-time X-ray CT scanning. Overall, substantial shrinkage of 52-74% of initial tissue volume was noted. The shrinkage was non-uniform over time and space, with observed asymmetry favouring the radial (23-43 % range) over the longitudinal (21-29%) direction. Algorithmic relationships for the shrinkage as a function of time were demonstrated. Furthermore, the smallest cubes showed more substantial and faster contraction (28-40% after 1 min), with more considerable volumetric shrinkage (>10%) in muscle than in liver tissue. Additionally, CT imaging demonstrated initial expansion of the tissue volume, lasting in some cases up to 3 min during the microwave ablation procedure, prior to the contraction phenomenon. In addition to an asymmetric substantial shrinkage of the ablated tissue volume, an initial expansion phenomenon occurs during MW ablation. Thus, complex modifications of the tissue close to a radiating antenna will likely need to be taken into account for future methods of real-time ablation monitoring.

Time-Dependent Behavior of Shrinkage Strain for Early Age Concrete Affected by Temperature Variation

OpenAIRE

Qin, Yu; Yi, Zhijian; Wang, Weina; Wang, Di

2017-01-01

Shrinkage has been proven to be an important property of early age concrete. The shrinkage strain leads to inherent engineering problems, such as cracking and loss of prestress. Atmospheric temperature is an important factor in shrinkage strain. However, current research does not provide much attention to the effect of atmospheric temperature on shrinkage of early age concrete. In this paper, a laboratory study was undertaken to present the time-dependent shrinkage of early age concrete under...

Effect of the key mixture parameters on shrinkage of reactive powder concrete.

Science.gov (United States)

Ahmad, Shamsad; Zubair, Ahmed; Maslehuddin, Mohammed

2014-01-01

Reactive powder concrete (RPC) mixtures are reported to have excellent mechanical and durability characteristics. However, such concrete mixtures having high amount of cementitious materials may have high early shrinkage causing cracking of concrete. In the present work, an attempt has been made to study the simultaneous effects of three key mixture parameters on shrinkage of the RPC mixtures. Considering three different levels of the three key mixture factors, a total of 27 mixtures of RPC were prepared according to 3(3) factorial experiment design. The specimens belonging to all 27 mixtures were monitored for shrinkage at different ages over a total period of 90 days. The test results were plotted to observe the variation of shrinkage with time and to see the effects of the key mixture factors. The experimental data pertaining to 90-day shrinkage were used to conduct analysis of variance to identify significance of each factor and to obtain an empirical equation correlating the shrinkage of RPC with the three key mixture factors. The rate of development of shrinkage at early ages was higher. The water to binder ratio was found to be the most prominent factor followed by cement content with the least effect of silica fume content.

A Regularized Approach for Solving Magnetic Differential Equations and a Revised Iterative Equilibrium Algorithm

International Nuclear Information System (INIS)

Hudson, S.R.

2010-01-01

A method for approximately solving magnetic differential equations is described. The approach is to include a small diffusion term to the equation, which regularizes the linear operator to be inverted. The extra term allows a 'source-correction' term to be defined, which is generally required in order to satisfy the solvability conditions. The approach is described in the context of computing the pressure and parallel currents in the iterative approach for computing magnetohydrodynamic equilibria.

Towards Current Profile Control in ITER: Potential Approaches and Research Needs

Science.gov (United States)

Schuster, E.; Barton, J. E.; Wehner, W. P.

2014-10-01

Many challenging plasma control problems still need to be addressed in order for the ITER Plasma Control System (PCS) to be able to successfully achieve the ITER project goals. For instance, setting up a suitable toroidal current density profile is key for one possible advanced scenario characterized by noninductive sustainment of the plasma current and steady-state operation. The nonlinearity and high dimensionality exhibited by the plasma demand a model-based current-profile control synthesis procedure that can accommodate this complexity through embedding the known physics within the design. The development of a model capturing the dynamics of the plasma relevant for control design enables not only the design of feedback controllers for regulation or tracking but also the design of optimal feedforward controllers for a systematic model-based approach to scenario planning, the design of state estimators for a reliable real-time reconstruction of the plasma internal profiles based on limited and noisy diagnostics, and the development of a fast predictive simulation code for closed-loop performance evaluation before implementation. Progress towards control-oriented modeling of the current profile evolution and associated control design has been reported following both data-driven and first-principles-driven approaches. An overview of these two approaches will be provided, as well as a discussion on research needs associated with each one of the model applications described above. Supported by the US Department of Energy under DE-SC0001334 and DE-SC0010661.

Evaluation of shrinkage and cracking in concrete of ring test by acoustic emission method

Science.gov (United States)

Watanabe, Takeshi; Hashimoto, Chikanori

2015-03-01

Drying shrinkage of concrete is one of the typical problems related to reduce durability and defilation of concrete structures. Lime stone, expansive additive and low-heat Portland cement are used to reduce drying shrinkage in Japan. Drying shrinkage is commonly evaluated by methods of measurement for length change of mortar and concrete. In these methods, there is detected strain due to drying shrinkage of free body, although visible cracking does not occur. In this study, the ring test was employed to detect strain and age cracking of concrete. The acoustic emission (AE) method was adopted to detect micro cracking due to shrinkage. It was recognized that in concrete using lime stone, expansive additive and low-heat Portland cement are effective to decrease drying shrinkage and visible cracking. Micro cracking due to shrinkage of this concrete was detected and evaluated by the AE method.

Shrinkage Estimators for Robust and Efficient Inference in Haplotype-Based Case-Control Studies

KAUST Repository

Chen, Yi-Hau; Chatterjee, Nilanjan; Carroll, Raymond J.

2009-01-01

Case-control association studies often aim to investigate the role of genes and gene-environment interactions in terms of the underlying haplotypes (i.e., the combinations of alleles at multiple genetic loci along chromosomal regions). The goal of this article is to develop robust but efficient approaches to the estimation of disease odds-ratio parameters associated with haplotypes and haplotype-environment interactions. We consider "shrinkage" estimation techniques that can adaptively relax the model assumptions of Hardy-Weinberg-Equilibrium and gene-environment independence required by recently proposed efficient "retrospective" methods. Our proposal involves first development of a novel retrospective approach to the analysis of case-control data, one that is robust to the nature of the gene-environment distribution in the underlying population. Next, it involves shrinkage of the robust retrospective estimator toward a more precise, but model-dependent, retrospective estimator using novel empirical Bayes and penalized regression techniques. Methods for variance estimation are proposed based on asymptotic theories. Simulations and two data examples illustrate both the robustness and efficiency of the proposed methods.

Shrinkage Estimators for Robust and Efficient Inference in Haplotype-Based Case-Control Studies

KAUST Repository

Chen, Yi-Hau

2009-03-01

Case-control association studies often aim to investigate the role of genes and gene-environment interactions in terms of the underlying haplotypes (i.e., the combinations of alleles at multiple genetic loci along chromosomal regions). The goal of this article is to develop robust but efficient approaches to the estimation of disease odds-ratio parameters associated with haplotypes and haplotype-environment interactions. We consider "shrinkage" estimation techniques that can adaptively relax the model assumptions of Hardy-Weinberg-Equilibrium and gene-environment independence required by recently proposed efficient "retrospective" methods. Our proposal involves first development of a novel retrospective approach to the analysis of case-control data, one that is robust to the nature of the gene-environment distribution in the underlying population. Next, it involves shrinkage of the robust retrospective estimator toward a more precise, but model-dependent, retrospective estimator using novel empirical Bayes and penalized regression techniques. Methods for variance estimation are proposed based on asymptotic theories. Simulations and two data examples illustrate both the robustness and efficiency of the proposed methods.

A systematic iterative approach to the equations of low type

International Nuclear Information System (INIS)

Znojil, M.

1987-01-01

Nonlinear singular integral equations of the Low type appear in the description of π-N scattering amplitude at relativistic energies. The standard iteration solution differs and does not give sufficiently exact results even using the Pade approximation. A new approach is proposed. Its essence lies in a repeated formal simplification of the equation accompanied by a representation of the simplified amplitude in a generalized continued-fractional form. A simple example demonstrate that the new method improves the convergence of previous approach and essentially expands the region of its convergence. From the other side, its nonequivalence to a more complicate Newton-Kantorovich method is shown. In the future more realistic applications of the method one can expect increasing of result reliability

Shrinkage Behaviour of Fibre Reinforced Concrete with Recycled Tyre Polymer Fibres

Directory of Open Access Journals (Sweden)

Marijana Serdar

2015-01-01

Full Text Available Different types of fibres are often used in concrete to prevent microcracking due to shrinkage, and polypropylene fibres are among the most often used ones. If not prevented, microcracks can lead to the development of larger cracks as drying shrinkage occurs, enabling penetration of aggressive substances from the environment and reducing durability of concrete structures. The hypothesis of the present research is that polypropylene fibres, used in concrete for controlling formation of microcracks due to shrinkage, can be replaced with recycled polymer fibres obtained from end-of-life tyres. To test the hypothesis, concrete mixtures containing polypropylene fibres and recycled tyre polymer fibres were prepared and tested. Experimental programme focused on autogenous, free, and restrained shrinkage. It was shown that PP fibres can be substituted with higher amount of recycled tyre polymer fibres obtaining concrete with similar shrinkage behaviour. The results indicate promising possibilities of using recycled tyre polymer fibres in concrete products. At the same time, such applications would contribute to solving the problem of waste tyre disposal.

Hydration of mineral shrinkage-compensating admixture for concrete : an experimental and numerical study

NARCIS (Netherlands)

Chen, Wei; Brouwers, H.J.H.

2012-01-01

The use of shrinkage-compensating admixture in concrete has been proven to be an effective way to mitigate the shrinkage of concrete. The hydration of a shrinkage-compensating admixture in cement paste and concrete is investigated in this paper with numerical simulation and experimental study. An

Strength and Drying Shrinkage of Alkali-Activated Slag Paste and Mortar

Directory of Open Access Journals (Sweden)

Mao-chieh Chi

2012-01-01

Full Text Available The aim of this study is to investigate the strengths and drying shrinkage of alkali-activated slag paste and mortar. Compressive strength, tensile strength, and drying shrinkage of alkali-activated slag paste and mortar were measured with various liquid/slag ratios, sand/slag ratios, curing ages, and curing temperatures. Experimental results show that the higher compressive strength and tensile strength have been observed in the higher curing temperature. At the age of 56 days, AAS mortars show higher compressive strength than Portland cement mortars and AAS mortars with liquid/slag ratio of 0.54 have the highest tensile strength in all AAS mortars. In addition, AAS pastes of the drying shrinkage are higher than AAS mortars. Meanwhile, higher drying shrinkage was observed in AAS mortars than that observed comparable Portland cement mortars.

ITER safety and operational scenario

International Nuclear Information System (INIS)

Shimomura, Y.; Saji, G.

1998-01-01

The safety and environmental characteristics of ITER and its operational scenario are described. Fusion has built-in safety characteristics without depending on layers of safety protection systems. Safety considerations are integrated in the design by making use of the intrinsic safety characteristics of fusion adequate to the moderate hazard inventories. In addition to this, a systematic nuclear safety approach has been applied to the design of ITER. The safety assessment of the design shows how ITER will safely accommodate uncertainties, flexibility of plasma operations, and experimental components, which is fundamental in ITER, the first experimental fusion reactor. The operation of ITER will progress step by step from hydrogen plasma operation with low plasma current, low magnetic field, short pulse and low duty factor without fusion power to deuterium-tritium plasma operation with full plasma current, full magnetic field, long pulse and high duty factor with full fusion power. In each step, characteristics of plasma and optimization of plasma operation will be studied which will significantly reduce uncertainties and frequency/severity of plasma transient events in the next step. This approach enhances reliability of ITER operation. (orig.)

Polymerization shrinkage stress of composite resins and resin cements – What do we need to know?

Directory of Open Access Journals (Sweden)

Carlos José SOARES

2017-08-01

Full Text Available Abstract Polymerization shrinkage stress of resin-based materials have been related to several unwanted clinical consequences, such as enamel crack propagation, cusp deflection, marginal and internal gaps, and decreased bond strength. Despite the absence of strong evidence relating polymerization shrinkage to secondary caries or fracture of posterior teeth, shrinkage stress has been associated with post-operative sensitivity and marginal stain. The latter is often erroneously used as a criterion for replacement of composite restorations. Therefore, an indirect correlation can emerge between shrinkage stress and the longevity of composite restorations or resin-bonded ceramic restorations. The relationship between shrinkage and stress can be best studied in laboratory experiments and a combination of various methodologies. The objective of this review article is to discuss the concept and consequences of polymerization shrinkage and shrinkage stress of composite resins and resin cements. Literature relating to polymerization shrinkage and shrinkage stress generation, research methodologies, and contributing factors are selected and reviewed. Clinical techniques that could reduce shrinkage stress and new developments on low-shrink dental materials are also discussed.

Modeling for prediction of restrained shrinkage effect in concrete repair

International Nuclear Information System (INIS)

Yuan Yingshu; Li Guo; Cai Yue

2003-01-01

A general model of autogenous shrinkage caused by chemical reaction (chemical shrinkage) is developed by means of Arrhenius' law and a degree of chemical reaction. Models of tensile creep and relaxation modulus are built based on a viscoelastic, three-element model. Tests of free shrinkage and tensile creep were carried out to determine some coefficients in the models. Two-dimensional FEM analysis based on the models and other constitutions can predict the development of tensile strength and cracking. Three groups of patch-repaired beams were designed for analysis and testing. The prediction from the analysis shows agreement with the test results. The cracking mechanism after repair is discussed

Iterative Perceptual Learning for Social Behavior Synthesis

NARCIS (Netherlands)

de Kok, I.A.; Poppe, Ronald Walter; Heylen, Dirk K.J.

We introduce Iterative Perceptual Learning (IPL), a novel approach for learning computational models for social behavior synthesis from corpora of human-human interactions. The IPL approach combines perceptual evaluation with iterative model refinement. Human observers rate the appropriateness of

Iterative Refinement Methods for Time-Domain Equalizer Design

Directory of Open Access Journals (Sweden)

Evans Brian L

2006-01-01

Full Text Available Commonly used time domain equalizer (TEQ design methods have been recently unified as an optimization problem involving an objective function in the form of a Rayleigh quotient. The direct generalized eigenvalue solution relies on matrix decompositions. To reduce implementation complexity, we propose an iterative refinement approach in which the TEQ length starts at two taps and increases by one tap at each iteration. Each iteration involves matrix-vector multiplications and vector additions with matrices and two-element vectors. At each iteration, the optimization of the objective function either improves or the approach terminates. The iterative refinement approach provides a range of communication performance versus implementation complexity tradeoffs for any TEQ method that fits the Rayleigh quotient framework. We apply the proposed approach to three such TEQ design methods: maximum shortening signal-to-noise ratio, minimum intersymbol interference, and minimum delay spread.

Design changes of device to investigation of alloys linear contraction and shrinkage stresses

Directory of Open Access Journals (Sweden)

J. Mutwil

2009-07-01

Full Text Available Some design changes in device elaborated by author to examination of linear contraction and shrinkage stresses progress of metals and alloys during– and after solidification have been described. The introduced changes have been focused on design of closing of shrinkage test rod mould. The introduced changes have been allowed to simplify a mounting procedure of thermocouples measuring a temperature of the shrinkage rod casting (in 6 points. Exemplary investigation results of linear contraction and shrinkage stresses development in Al-Si13.5% alloy have been presented.

Drying Shrinkage of Mortar Incorporating High Volume Oil Palm Biomass Waste

Science.gov (United States)

Shukor Lim, Nor Hasanah Abdul; Samadi, Mostafa; Rahman Mohd. Sam, Abdul; Khalid, Nur Hafizah Abd; Nabilah Sarbini, Noor; Farhayu Ariffin, Nur; Warid Hussin, Mohd; Ismail, Mohammed A.

2018-03-01

This paper studies the drying shrinkage of mortar incorporating oil palm biomass waste including Palm Oil Fuel Ash, Oil Palm Kernel Shell and Oil Palm Fibre. Nano size of palm oil fuel ash was used up to 80 % as cement replacement by weight. The ash has been treated to improve the physical and chemical properties of mortar. The mass ratio of sand to blended ashes was 3:1. The test was carried out using 25 × 25 × 160 mm prism for drying shrinkage tests and 70 × 70 ×70 mm for compressive strength test. The results show that the shrinkage value of biomass mortar is reduced by 31% compared with OPC mortar thus, showing better performance in restraining deformation of the mortar while the compressive strength increased by 24% compared with OPC mortar at later age. The study gives a better understanding of how the biomass waste affect on mortar compressive strength and drying shrinkage behaviour. Overall, the oil palm biomass waste can be used to produce a better performance mortar at later age in terms of compressive strength and drying shrinkage.

Plastic shrinkage of mortars with shrinkage reducing admixture and lightweight aggregates studied by neutron tomography

International Nuclear Information System (INIS)

Wyrzykowski, Mateusz; Trtik, Pavel; Münch, Beat; Weiss, Jason; Vontobel, Peter; Lura, Pietro

2015-01-01

Water transport in fresh, highly permeable concrete and rapid water evaporation from the concrete surface during the first few hours after placement are the key parameters influencing plastic shrinkage cracking. In this work, neutron tomography was used to determine both the water loss from the concrete surface due to evaporation and the redistribution of fluid that occurs in fresh mortars exposed to external drying. In addition to the reference mortar with a water to cement ratio (w/c) of 0.30, a mortar with the addition of pre-wetted lightweight aggregates (LWA) and a mortar with a shrinkage reducing admixture (SRA) were tested. The addition of SRA reduced the evaporation rate from the mortar at the initial stages of drying and reduced the total water loss. The pre-wetted LWA released a large part of the absorbed water as a consequence of capillary pressure developing in the fresh mortar due to evaporation

Plastic shrinkage of mortars with shrinkage reducing admixture and lightweight aggregates studied by neutron tomography

Energy Technology Data Exchange (ETDEWEB)

Wyrzykowski, Mateusz, E-mail: mateusz.wyrzykowski@empa.ch [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Dübendorf (Switzerland); Lodz University of Technology, Department of Building Physics and Building Materials, Lodz (Poland); Trtik, Pavel [Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, Villigen (Switzerland); Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Dübendorf (Switzerland); Münch, Beat [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Dübendorf (Switzerland); Weiss, Jason [Purdue University, School of Civil Engineering, West Lafayette (United States); Vontobel, Peter [Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, Villigen (Switzerland); Lura, Pietro [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Dübendorf (Switzerland); ETH Zurich, Institute for Building Materials (IfB), Zurich (Switzerland)

2015-07-15

Water transport in fresh, highly permeable concrete and rapid water evaporation from the concrete surface during the first few hours after placement are the key parameters influencing plastic shrinkage cracking. In this work, neutron tomography was used to determine both the water loss from the concrete surface due to evaporation and the redistribution of fluid that occurs in fresh mortars exposed to external drying. In addition to the reference mortar with a water to cement ratio (w/c) of 0.30, a mortar with the addition of pre-wetted lightweight aggregates (LWA) and a mortar with a shrinkage reducing admixture (SRA) were tested. The addition of SRA reduced the evaporation rate from the mortar at the initial stages of drying and reduced the total water loss. The pre-wetted LWA released a large part of the absorbed water as a consequence of capillary pressure developing in the fresh mortar due to evaporation.

Influence of shrinkage porosity on fatigue performance of iron castings and life estimation method

Directory of Open Access Journals (Sweden)

Wei Liu

2016-01-01

Full Text Available Shrinkage porosity exists more or less in heavy castings, and it plays an important role in the fatigue behavior of cast materials. In this study, fatigue tests were carried out on the QT400-18 cast iron specimens containing random degrees of shrinkage porosity defect. Experimental results showed that the order of magnitude of life scattered from 103 to 106 cycles when the shrinkage percentage ranged from 0.67% to 5.91%. SEM analyses were carried out on the shrinkage porosity region. The inter-granular discontinuous, micro cracks and inclusions interfered with the fatigue sliding or hindering process. The slip in shrinkage porosity region was not as orderly as the ordinary continuous medium. The shrinkage porosity area on fracture surface (SPAFS and alternating stress intensity factor (ASIF were applied to evaluate the tendency of residual life distribution; their relationship was fitted by negative exponent functions. Based on the intermediate variable of ASIF, a fatigue life prediction model of nodular cast iron containing shrinkage porosity defects was established. The modeling prediction was in agreement with the experimental results.

Influence of fly ash fineness on water requirement and shrinkage of blended cement mortars

Directory of Open Access Journals (Sweden)

Vanissorn Vimonsatit

2015-12-01

Full Text Available In this paper, the influence of fly ash fineness on water requirement and shrinkage of blended cement mortar was studied. The results indicate that the water requirement and shrinkage characteristic of the blended cement mortar are dependent on fly ash fineness and replacement level. The use of coarse fly ash slightly reduces the water requirement but greatly reduced the drying and the autogenous shrinkage of the blended cement mortars and the reduction is more with an increase in the fly ash replacement level. The finer fly ashes further reduce the water requirement, but increase the drying and the autogenous shrinkages as compared with coarser fly ash. The incorporation of superplasticizer drastically reduces the water requirement, but the effect on the drying and autogenous shrinkages of the normal Portland cement mortar is small. However, for the fly ash mortar, the use of superplasticizer results in a decrease in drying shrinkage and in a substantial increase in the autogenous shrinkage particularly for the fine fly ash at a high replacement level.

Prediction of shrinkage cracking age of concrete with and without expansive additive

Directory of Open Access Journals (Sweden)

Dung Tien Nguyen

2010-10-01

Full Text Available The aim of this research is to propose a model for predicting cracking age of concrete due to restrained shrinkage. Thisstudy focuses on analyzing shrinkage and expansion mechanisms in the expansive concrete to formulate a model that can beemployed to predict whether shrinkage cracking occurs or not. In case of conventional (non-expansive concrete, this modelcan be applied by neglecting the early expansion due to expansive additive. Parameters considered in this model are restrainedexpansion, free shrinkage, cracking strain that can be experimentally measured by experiment and tensile creep which isderived by back calculation. The model was verified by test results of expansive concrete mixtures as well as normal concretemixtures both with and without fly ash.

Can superabsorbent polymers mitigate shrinkage in cementitious materials blended with supplementary cementitious materials?

DEFF Research Database (Denmark)

Snoeck, Didier; Jensen, Ole Mejlhede; De Belie, Nele

2016-01-01

A promising way to mitigate autogenous shrinkage in cementitious materials with a low water-to-binder ratio is internal curing by the use of superabsorbent polymers. Superabsorbent polymers are able to absorb multiple times their weight in water and can be applied as an internal water reservoir...... to induce internal curing and mitigation of self-desiccation. Their purposefulness has been demonstrated in Portland cement pastes with and without silica fume. Nowadays, fly ash and blast-furnace slag containing binders are also frequently used in the construction industry. The results on autogenous...... shrinkage in materials blended with fly ash or blast-furnace slag remain scarce, especially after one week of age. This paper focuses on the autogenous shrinkage by performing manual and automated shrinkage measurements up to one month of age. Without superabsorbent polymers, autogenous shrinkage...

Effects of Shrinkage Reducing Agent and Expansive Additive on Mortar Properties

OpenAIRE

Treesuwan, Sarapon; Maleesee, Komsan

2017-01-01

This research is to study the effect of mortar mixed with shrinkage reducing agent (polyoxyalkylene alkyl ether type), expansive additive (CaO type), and fly ash (hereinafter “SRA,” “EX,” and “FA,” resp.). Moreover, steam curing was studied to improve the properties of mortar. The plastic shrinkage test was conducted by using the strain gauge embedded at 0.5 cm from the surface according to the ASTM C1579-06 standard within early age followed by the total shrinkage test and compressive streng...

An Iterative Load Disaggregation Approach Based on Appliance Consumption Pattern

Directory of Open Access Journals (Sweden)

Huijuan Wang

2018-04-01

Full Text Available Non-intrusive load monitoring (NILM, monitoring single-appliance consumption level by decomposing the aggregated energy consumption, is a novel and economic technology that is beneficial to energy utilities and energy demand management strategies development. Hardware costs of high-frequency sampling and algorithm’s computational complexity hampered NILM large-scale application. However, low sampling data shows poor performance in event detection when multiple appliances are simultaneously turned on. In this paper, we contribute an iterative disaggregation approach that is based on appliance consumption pattern (ILDACP. Our approach combined Fuzzy C-means clustering algorithm, which provide an initial appliance operating status, and sub-sequence searching Dynamic Time Warping, which retrieves single energy consumption based on the typical power consumption pattern. Results show that the proposed approach is effective to accurately disaggregate power consumption, and is suitable for the situation where different appliances are simultaneously operated. Also, the approach has lower computational complexity than Hidden Markov Model method and it is easy to implement in the household without installing special equipment.

Self-compacting fine-grained concretes with compensated shrinkage

Directory of Open Access Journals (Sweden)

Alimov Lev

2017-01-01

Full Text Available This paper substantiates the efficiency of application of fine-grained concrete for erection of cast-in-place concrete and reinforced concrete structures of different purpose. On the basis of analysis of experimental research results it was established that the introduction of microfillers with expansion effect to composite binder allows not only improving the rheological properties of fine-grained concrete, but also decreasing of value of shrinkage strain and improving of concrete crack resistance and durability. The analysis of the results of industrial use of fine-grained concretes with compensated shrinkage is given.

Topology optimization of reinforced concrete structures considering control of shrinkage and strength failure

DEFF Research Database (Denmark)

Luo, Yangjun; Wang, Michael Yu; Zhou, Mingdong

2015-01-01

To take into account the shrinkage effect in the early stage of Reinforced Concrete (RC) design, an effective continuum topology optimization method is presented in this paper. Based on the power-law interpolation, shrinkage of concrete is numerically simulated by introducing an additional design......-dependent force. Under multi-axial stress conditions, the concrete failure surface is well fitted by two Drucker-Prager yield functions. The optimization problem aims at minimizing the cost function under yield strength constraints on concrete elements and a structural shrinkage volume constraint. In conjunction...... to ensure the structural safety under the combined action of external loads and shrinkage....

Quantitative determination of additive Chlorantraniliprole in Abamectin preparation: Investigation of bootstrapping soft shrinkage approach by mid-infrared spectroscopy

Science.gov (United States)

Yan, Hong; Song, Xiangzhong; Tian, Kuangda; Chen, Yilin; Xiong, Yanmei; Min, Shungeng

2018-02-01

A novel method, mid-infrared (MIR) spectroscopy, which enables the determination of Chlorantraniliprole in Abamectin within minutes, is proposed. We further evaluate the prediction ability of four wavelength selection methods, including bootstrapping soft shrinkage approach (BOSS), Monte Carlo uninformative variable elimination (MCUVE), genetic algorithm partial least squares (GA-PLS) and competitive adaptive reweighted sampling (CARS) respectively. The results showed that BOSS method obtained the lowest root mean squared error of cross validation (RMSECV) (0.0245) and root mean squared error of prediction (RMSEP) (0.0271), as well as the highest coefficient of determination of cross-validation (Qcv2) (0.9998) and the coefficient of determination of test set (Q2test) (0.9989), which demonstrated that the mid infrared spectroscopy can be used to detect Chlorantraniliprole in Abamectin conveniently. Meanwhile, a suitable wavelength selection method (BOSS) is essential to conducting a component spectral analysis.

Investigations of linear contraction and shrinkage stresses development in hypereutectic al-si binary alloys

Directory of Open Access Journals (Sweden)

J. Mutwil

2009-07-01

Full Text Available Shrinkage phenomena during solidification and cooling of hypereutectic aluminium-silicon alloys (AlSi18, AlSi21 have been examined. A vertical shrinkage rod casting with circular cross-section (constant or fixed: tapered has been used as a test sample. Two type of experiments have been conducted: 1 on development of the test sample linear dimension changes (linear expansion/contraction, 2 on development of shrinkage stresses in the test sample. By the linear contraction experiments the linear dimension changes of the test sample and the metal test mould as well a temperature in six points of the test sample have been registered. By shrinkage stresses examination a shrinkage tension force and linear dimension changes of the test sample as well a temperature in three points of the test sample have been registered. Registered time dependences of the test bar and the test mould linear dimension changes have shown, that so-called pre-shrinkage extension has been mainly by mould thermal extension caused. The investigation results have shown that both: the linear contraction as well as the shrinkage stresses development are evident dependent on metal temperature in a warmest region the sample (thermal centre.

Effects of drying conditions, admixtures and specimen size on shrinkage strains

International Nuclear Information System (INIS)

Al-Saleh, Saleh A.; Al-Zaid, Rajeh Z.

2006-01-01

The paper presents the results of an experimental investigation on the effects of drying conditions, specimen size and presence of plasticizing admixture on the development of shrinkage strains. The measurements are taken in a harsh (50 deg. C and 5% R.H.) and a moderate environment (28 deg. C and 50% R.H.). The results include strain development at various levels of cross sections of concrete prisms. The drying conditions are found to be the dominant parameter affecting the shrinkage strain development particularly in specimens of smaller sizes. The effect of plasticizing admixture on shrinkage strains is negligible

On equivalence classes in iterative learning control

NARCIS (Netherlands)

Verwoerd, M.H.A.; Meinsma, Gjerrit; de Vries, Theodorus J.A.

2003-01-01

This paper advocates a new approach to study the relation between causal iterative learning control (ILC) and conventional feedback control. Central to this approach is the introduction of the set of admissible pairs (of operators) defined with respect to a family of iterations. Considered are two

An Experimental Study on Shrinkage Strains of Normal-and High-Strength Concrete-Filled Frp Tubes

Science.gov (United States)

Vincent, Thomas; Ozbakkaloglu, Togay

2017-09-01

It is now well established that concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs) are an attractive construction technique for new columns, however studies examining concrete shrinkage in CFFTs remain limited. Concrete shrinkage may pose a concern for CFFTs, as in these members the curing of concrete takes place inside the FRP tube. This paper reports the findings from an experimental study on concrete shrinkage strain measurements for CFFTs manufactured with normal- and high-strength concrete (NSC and HSC). A total of 6 aramid FRP (AFRP)-confined concrete specimens with circular cross-sections were manufactured, with 3 specimens each manufactured using NSC and HSC. The specimens were instrumented with surface and embedded strain gauges to monitor shrinkage development of exposed concrete and concrete sealed inside the CFFTs, respectively. All specimens were cylinders with a 152 mm diameter and 305 mm height, and their unconfined concrete strengths were 44.8 or 83.2 MPa. Analysis of the shrinkage measurements from concrete sealed inside the CFFTs revealed that embedment depth and concrete compressive strength only had minor influences on recorded shrinkage strains. However, an analysis of shrinkage measurements from the exposed concrete surface revealed that higher amounts of shrinkage can occur in HSC. Finally, it was observed that shrinkage strains are significantly higher for concrete exposed at the surface compared to concrete sealed inside the CFFTs.

Shrinkage stress in concrete under dry-wet cycles: an example with concrete column

Science.gov (United States)

Gao, Yuan; Zhang, Jun; Luosun, Yiming

2014-02-01

This paper focuses on the simulation of shrinkage stress in concrete structures under dry-wet environments. In the modeling, an integrative model for autogenous and drying shrinkage predictions of concrete under dry-wet cycles is introduced first. Second, a model taking both cement hydration and moisture diffusion into account synchronously is used to calculate the distribution of interior humidity in concrete. Using the above two models, the distributions of shrinkage strain and stress in concrete columns made by normal and high strength concrete respectively under dry-wet cycles are calculated. The model results show that shrinkage gradient along the radial direction of the column from the center to outer surface increases with age as the outer circumference suffers to dry. The maximum and minimum shrinkage occur at the outer surface and the center of the column, respectively, under drying condition. As wetting starts, the shrinkage strain decreases with increase of interior humidity. The closer to the wetting face, the higher the humidity and the lower the shrinkage strain, as well as the lower the shrinkage stress. As results of the dry-wet cycles acting on the outer circumference of the column, cyclic stress status is developed within the area close to the outer surface of the column. The depth of the influencing zone of dry-wet cyclic action is influenced by concrete strength and dry-wet regime. For low strength concrete, relatively deeper influencing zone is expected compared with that of high strength concrete. The models are verified by concrete-steel composite ring tests and a good agreement between model and test results is found.

The effect of fibers on the loss of water by evaporation and shrinkage of concrete

Directory of Open Access Journals (Sweden)

N. M. P. Pillar

Full Text Available Shrinkage is one of the least desirable attributes in concrete. Large areas of exposed concrete surfaces , such as in shotcrete tunnel linings, where it is practically impossible to make a moist cure, are highly susceptible to plastic shrinkage at early ages. The autogenous and drying shrinkage can lead to states of greater than threshold strength, causing fracture, mechanical damage and lack of durability of concrete structures. The addition of fibers can greatly reduce plastic shrinkage, but has limited effect in mitigating autogenous and drying shrinkage. To evaluate the performance of polypropylene and steel fibers to understand their effect on shrinkage of concrete, a study was carried out to relate the loss of water from the paste and the shrinkage during the first 28 days of age, and compare it with a control mix without fiber. The loss of water was obtained by the weight loss of the specimens at different ages, since the only component that could contribute for the loss of weight was the water lost by the paste of the concrete. And the paste itself is the only source of shrinkage. Uniaxial compressive tests from very early ages enabled the determination of time when plastic shrinkage ended. It was observed that the control concrete mix lost three times more water and developed plastic and drying shrinkage 60 % higher than the fiber reinforced concrete mixes. It was possible to demonstrate that the reduced loss of water caused by the incorporation of fibers is related to the mitigation of plastic shrinkage. It was observed that the fibers are effective to restrain the movement of water through the cement paste in the plastic state, however such effect is limited after concrete starts the hardening state.

Electromagnetic scattering using the iterative multi-region technique

CERN Document Server

Al Sharkawy, Mohamed H

2007-01-01

In this work, an iterative approach using the finite difference frequency domain method is presented to solve the problem of scattering from large-scale electromagnetic structures. The idea of the proposed iterative approach is to divide one computational domain into smaller subregions and solve each subregion separately. Then the subregion solutions are combined iteratively to obtain a solution for the complete domain. As a result, a considerable reduction in the computation time and memory is achieved. This procedure is referred to as the iterative multiregion (IMR) technique.Different enhan

Digital image analysis of radial shrinkage of fresh spruce (Picea abies L.) wood.

Science.gov (United States)

Hansmann, Christian; Konnerth, Johannes; Rosner, Sabine

2011-03-21

Contact-free digital image analysis was performed of the radial shrinkage of fresh, fully saturated small spruce wood beams. An experimental test set-up was developed to ensure constant distance from the charge-coupled device camera to the sample surface as well as constant climate and light conditions during the whole experiment. Dimensional changes were observed immediately after the drying process began. An unexpected distinct effect could be observed which could not be explained by drying surface layers only. After a fast initial radial shrinkage a slowing down of the dimensional changes occurred at high mean moisture contents. A complete interruption of any dimensional changes followed. Finally, a recovery from shrinkage was even observed. It is assumed that strong negative pressure occurred in the fully saturated capillaries owing to dehydration which led to additional dimensional changes. As a consequence, the break of the water column and aeration in these capillaries finally resulted in a recovery period in the shrinkage rate due to the pressure release. After this effect, the dehydration was characterized by a phase of fast and almost linear shrinkage due to drying surface layers. Finally, the shrinkage slowed down to zero when reaching equilibrium moisture content.

An Iterative, Mixed Usability Approach Applied to the Telekit System from the Danish TeleCare North Trial

Science.gov (United States)

Schaarup, Clara; Hejlesen, Ole Kristian

2016-01-01

Objective. The aim of the present study is to evaluate the usability of the telehealth system, coined Telekit, by using an iterative, mixed usability approach. Materials and Methods. Ten double experts participated in two heuristic evaluations (HE1, HE2), and 11 COPD patients attended two think-aloud tests. The double experts identified usability violations and classified them into Jakob Nielsen's heuristics. These violations were then translated into measurable values on a scale of 0 to 4 indicating degree of severity. In the think-aloud tests, COPD participants were invited to verbalise their thoughts. Results. The double experts identified 86 usability violations in HE1 and 101 usability violations in HE2. The majority of the violations were rated in the 0–2 range. The findings from the think-aloud tests resulted in 12 themes and associated examples regarding the usability of the Telekit system. The use of the iterative, mixed usability approach produced both quantitative and qualitative results. Conclusion. The iterative, mixed usability approach yields a strong result owing to the high number of problems identified in the tests because the double experts and the COPD participants focus on different aspects of Telekit's usability. This trial is registered with Clinicaltrials.gov, NCT01984840, November 14, 2013. PMID:27974888

Astrocytic mechanisms explaining neural-activity-induced shrinkage of extraneuronal space

DEFF Research Database (Denmark)

Østby, Ivar; Øyehaug, Leiv; Einevoll, Gaute T

2009-01-01

Neuronal stimulation causes approximately 30% shrinkage of the extracellular space (ECS) between neurons and surrounding astrocytes in grey and white matter under experimental conditions. Despite its possible implications for a proper understanding of basic aspects of potassium clearance and astr......Neuronal stimulation causes approximately 30% shrinkage of the extracellular space (ECS) between neurons and surrounding astrocytes in grey and white matter under experimental conditions. Despite its possible implications for a proper understanding of basic aspects of potassium clearance...... concentrations observed in connection with neuronal stimulation, the actions of the Na(+)/K(+)/Cl(-) (NKCC1) and the Na(+)/HCO(3) (-) (NBC) cotransporters appear to be critical determinants for achieving observed quantitative levels of ECS shrinkage. Considering the current state of knowledge, the model...

Moisture migration and shrinkage of hardened cement paste at elevated temperatures

International Nuclear Information System (INIS)

Numao, Tatsuya; Mihashi, Hirozo.

1991-01-01

The drying shrinkage of concrete is caused by the loss of water in the concrete. The moisture diffusion behavior influences the mechanical properties of concrete. When concrete is exposed to high temperature, the rate of moisture migration becomes fast, and moisture gradient is formed. This gradient causes cracks on the concrete surface. Accordingly, it is important to study on the relation between the drying shrinkage and the water diffusion in concrete when its mechanical properties at elevated temperature are discussed. In this paper, the results of the experiment which was carried out by using thin-walled cylinder specimens kept at different temperature and stress are reported. The specimens, the drying shrinkage of concrete and acoustic emission (AE), the thermal expansion of hardened cement paste, the influence that temperature change exerted to the drying shrinkage, and the influence that compressive stress and temperature exerted to water migration are described. The thin-walled cylinder specimens were useful for these experimental studies. (K.I.)

Shrinkage reduction of dental composites by addition of expandable zirconia filler

DEFF Research Database (Denmark)

Skovgaard, M.; Almdal, Kristoffer; Sørensen, Bent F.

2011-01-01

. The shrinkage of the composite was calculated from density measurements using Archimedes method. The rate of the phase transformation in resin was measured by determining the volume fraction of monoclinic zirconia (vm). The composite had a vm of 0.5 after 8 h of water storage. The overall shrinkage...

Strain mapping of LED devices by dark-field inline electron holography: Comparison between deterministic and iterative phase retrieval approaches

Energy Technology Data Exchange (ETDEWEB)

Song, Kyung; Shin, Ga-Young; Kim, Jong Kyu [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Nam-gu, Pohang 790-784 (Korea, Republic of); Oh, Sang Ho, E-mail: shoh@postech.ac.kr [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Nam-gu, Pohang 790-784 (Korea, Republic of); Koch, Christoph T. [Institute for Experimental Physics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm (Germany)

2013-04-15

Dark-field inline electron holography has recently been established as a convenient method to map strain in semiconductor devices, combining high precision, low noise, sub-nm spatial resolution and fields-of-view larger than 1 μm. Here we compare two approaches to reconstruct the geometric phase from a transmission electron microscopy dark-field focal series and their effects on the strain measurement: the transport-of-intensity-equation (TIE) and a flux-preserving iterative approach. For this task, we used a GaN-based light emitting diode with a highly complex heterostructure as a model system. While the TIE relies on 3 images only but requires the optimization of two free parameters (defocus step and low-limit cut-off frequency), the iterative reconstruction algorithm involves no adjustable parameters and uses images recorded at 9 different planes of focus with quadratically increasing defocus values. Optimum parameters for the TIE-reconstruction could be identified. However, the iterative phase retrieval approach yields the strain values that agree best with the expected strain levels and provides also higher spatial resolution.

Aerosol particle shrinkage event phenomenology in a South European suburban area during 2009-2015

Science.gov (United States)

Alonso-Blanco, E.; Gómez-Moreno, F. J.; Núñez, L.; Pujadas, M.; Cusack, M.; Artíñano, B.

2017-07-01

A high number of aerosol particle shrinkage cases (70) have been identified and analyzed from an extensive and representative database of aerosol size distributions obtained between 2009 and 2015 at an urban background site in Madrid (Spain). A descriptive classification based on the process from which the shrinkage began is proposed according which shrinkage events were divided into three groups: (1) NPF + shrinkage (NPF + S) events, (2) aerosol particle growth process + shrinkage (G + S) events, and (3) pure shrinkage (S) events. The largest number of shrinkages corresponded to the S-type followed by NPF + S, while the G + S events were the least frequent group recorded. Duration of shrinkages varied widely from 0.75 to 8.5 h and SR from -1.0 to -11.1 nm h-1. These processes typically occurred in the afternoon, around 18:00 UTC, caused by two situations: i) a wind speed increase usually associated with a change in the wind direction (over 60% of the observations) and ii) the reduction of photochemical activity at the end of the day. All shrinkages were detected during the warm period, mainly between May and August, when local meteorological conditions (high solar irradiance and temperature and low relative humidity), atmospheric processes (high photochemical activity) and availability of aerosol-forming precursors were favorable for their development. As a consequence of these processes, the particles concentration corresponding to the Aitken mode decreased into the nucleation mode. The accumulation mode did not undergo significant changes during these processes. In some cases, a dilution of the particulate content in the ambient air was observed. This work, goes further than others works dealing with aerosol particles shrinkages, as it incorporates as a main novelty a classification methodology for studying these processes. Moreover, compared to other studies, it is supported by a high and representative number of observations. Thus, this study contributes to

The ITER Remote Maintenance Management System

International Nuclear Information System (INIS)

Tesini, Alessandro; Rolfe, A.C.

2009-01-01

A major challenge for the ITER project is to develop and implement a Remote Maintenance System, which can deliver high Tokamak availability within the constraints of the overall ITER programme objectives. Much of the maintenance of ITER will be performed using remote handling methods and some with combined manual and remote activities working together. The organization and management of the ITER remote handling facilities will be of a scale unlike any other remote handling application in the world. The ITER remote handling design and procurement activities will require co-ordination and management across many different sites throughout the world. It will be a major challenge for the ITER project to ensure a consistent quality and technical approach in all of the contributing parties. To address this issue the IO remote handling team are implementing the ITER Maintenance Management Plan (IMMP) comprising an overarching document defining the policies and methodologies (ITER Remote Maintenance Management System or IMMS) and an associated ITER remote handling code of practise (IRHCOP). The IMMS will be in document form available as a pdf file or similar. The IRHCOP will be implemented as a web based application and will provide access to the central resource of the entire code of practise from any location in the world. The IRHCOP data library will be centrally controlled in order that users can be assured of the data relevance and authenticity. This paper will describe the overall approach being taken to deal with this challenge and go on to detail the structure and content of both the IMMS and the IRHCOP.

Novel aspects of plasma control in ITER

Energy Technology Data Exchange (ETDEWEB)

Humphreys, D.; Jackson, G.; Walker, M.; Welander, A. [General Atomics P.O. Box 85608, San Diego, California 92186-5608 (United States); Ambrosino, G.; Pironti, A. [CREATE/University of Naples Federico II, Napoli (Italy); Vries, P. de; Kim, S. H.; Snipes, J.; Winter, A.; Zabeo, L. [ITER Organization, St. Paul Lez durance Cedex (France); Felici, F. [Eindhoven University of Technology, Eindhoven (Netherlands); Kallenbach, A.; Raupp, G.; Treutterer, W. [Max-Planck Institut für Plasmaphysik, Garching (Germany); Kolemen, E. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States); Lister, J.; Sauter, O. [Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland); Moreau, D. [CEA, IRFM, 13108 St. Paul-lez Durance (France); Schuster, E. [Lehigh University, Bethlehem, Pennsylvania (United States)

2015-02-15

ITER plasma control design solutions and performance requirements are strongly driven by its nuclear mission, aggressive commissioning constraints, and limited number of operational discharges. In addition, high plasma energy content, heat fluxes, neutron fluxes, and very long pulse operation place novel demands on control performance in many areas ranging from plasma boundary and divertor regulation to plasma kinetics and stability control. Both commissioning and experimental operations schedules provide limited time for tuning of control algorithms relative to operating devices. Although many aspects of the control solutions required by ITER have been well-demonstrated in present devices and even designed satisfactorily for ITER application, many elements unique to ITER including various crucial integration issues are presently under development. We describe selected novel aspects of plasma control in ITER, identifying unique parts of the control problem and highlighting some key areas of research remaining. Novel control areas described include control physics understanding (e.g., current profile regulation, tearing mode (TM) suppression), control mathematics (e.g., algorithmic and simulation approaches to high confidence robust performance), and integration solutions (e.g., methods for management of highly subscribed control resources). We identify unique aspects of the ITER TM suppression scheme, which will pulse gyrotrons to drive current within a magnetic island, and turn the drive off following suppression in order to minimize use of auxiliary power and maximize fusion gain. The potential role of active current profile control and approaches to design in ITER are discussed. Issues and approaches to fault handling algorithms are described, along with novel aspects of actuator sharing in ITER.

Shrinkage Characteristics of Experimental Polymer Containing Composites under Controlled Light Curing Modes

Directory of Open Access Journals (Sweden)

Alain Pefferkorn

2012-01-01

Full Text Available The adsorption of polymethylmethacrylate polymer of different molecular weight at the aerosil/ethyleneglycol- or 1,3 butanediol-dimethacrylate interfaces was determined to provide microstructured networks. Their structural characteristics were determined to be controlled by the amount of polymer initially supplied to the system. The sediment (the settled phase characteristics, determined as a function of the polymer concentration and the rate of the polymerization shrinkage determined for composite resins, obtained by extrusion of the sediment after centrifugation, were found to be correlated. The specific role of the adsorbed polymer was found to be differently perturbed with the supplementary supply of dimethacrylate based monomer additives. Particularly, the bisphenol A dimethacrylate that generated crystals within the sediment was found to impede the shrinkage along the crystal lateral faces and strongly limit the shrinkage along its basal faces. Addition of ethyleneglycol- or polyethylene-glycoldimethacrylate monomers was determined to modify the sedimentation characteristics of the aerosil suspension and the shrinkage properties of the composites. Finally, the effects of stepwise light curing methods with prolonged lighting-off periods were investigated and found to modify the development and the final values of the composite shrinkage.

Fissure formation in coke. 2: Effect of heating rate, shrinkage and coke strength

Energy Technology Data Exchange (ETDEWEB)

D.R. Jenkins; M.R. Mahoney [CSIRO, North Ryde, NSW (Australia). Mathematical and Information Sciences

2010-07-15

We investigate the effects of the heating rate, coke shrinkage and coke breakage strength upon the fissure pattern developed in a coke oven charge during carbonisation. This is done principally using a mechanistic model of the formation of fissures, which considers them to be an array of equally spaced fissures, whose depth follows a 'period doubling' pattern based upon the time history of the fissures. The model results are compared with pilot scale coke oven experiments. The results show that the effect of heating rate on the fissure pattern is different to the effect of coke shrinkage, while the effect of coke breakage strength on the pattern is less pronounced. The results can be seen in both the shape and size of resulting coke lumps after stabilisation. The approach gives the opportunity to consider means of controlling the carbonisation process in order to tune the size of the coke lumps produced. 7 refs., 18 figs., 4 tabs.

Process and overview of diagnostics integration in ITER ports

International Nuclear Information System (INIS)

Drevon, J.M.; Walsh, M.; Andrew, P.; Barnsley, R.; Bertalot, L.; Bock, M. de; Bora, D.; Bouhamou, R.; Direz, M.F.; Encheva, A.; Fang, T.; Feder, R.; Giacomin, T.; Hellermann, M. von; Jakhar, S.; Johnson, D.; Kaschuk, Y.; Kusama, Y.; Lee, H.G.; Levesy, B.

2013-01-01

Highlights: ► An overview of the Port Integration hardware for tenant system hosting inside ITER diagnostics ports is given. ► The main challenges for diagnostic port integration engineering are presented. ► The actions taken for a common modular approach and a coordinated design are detailed. -- Abstract: ITER will have a set of 45 diagnostics to ensure controlled operation. Many of them are integrated in the ITER ports. This paper addresses the integration process of the diagnostic systems and the approach taken to enable coordinated progress. An overview of the Port Integration hardware introduces the various structures needed for hosting tenant systems inside ITER diagnostics ports. The responsibilities of the different parties involved (ITER Organization and the Domestic Agencies) are outlined. The main challenges for diagnostic port integration engineering are summarized. The plan for a common approach to design and manufacture of the supporting structures, in particular the Port Plug is detailed. A coordinated design including common components and a common approach for neutronic analyses is proposed. One particular port, the equatorial port 11, is used to illustrate the approach

A numerical analysis method on thermal and shrinkage stress of concrete

International Nuclear Information System (INIS)

Takiguchi, Katsuki; Hotta, Hisato

1991-01-01

Thermal stress often causes cracks in large scale concrete such as that for dam construction. The drying shrinkage of concrete causes cracks in concrete structures. These thermal stress and drying shrinkage stress may be the main reasons cracks occur in concrete, however there is few research which dealt with both stresses together. The problems on the thermal stress and the drying shrinkage are not independent, and should be dealt with together, because both temperature and water content of concrete affect hydration reaction, and the degree of hydration determines all the characteristics of concrete at early age. In this study, the degree of hydration is formulated experimentally, and a numerical stress analysis method taking the hydration reaction in consideration is presented. The formulation of the rate of hydration reaction, the method of analyzing thermal and drying shrinkage stresses, the analytical results for a concrete column and the influence that continuous load exerted to the tensile strength of concrete are reported. The relatively high stress nearly equal to the tensile strength of concrete arises near the surface. (K.I.)

An iterative stochastic ensemble method for parameter estimation of subsurface flow models

International Nuclear Information System (INIS)

Elsheikh, Ahmed H.; Wheeler, Mary F.; Hoteit, Ibrahim

2013-01-01

Parameter estimation for subsurface flow models is an essential step for maximizing the value of numerical simulations for future prediction and the development of effective control strategies. We propose the iterative stochastic ensemble method (ISEM) as a general method for parameter estimation based on stochastic estimation of gradients using an ensemble of directional derivatives. ISEM eliminates the need for adjoint coding and deals with the numerical simulator as a blackbox. The proposed method employs directional derivatives within a Gauss–Newton iteration. The update equation in ISEM resembles the update step in ensemble Kalman filter, however the inverse of the output covariance matrix in ISEM is regularized using standard truncated singular value decomposition or Tikhonov regularization. We also investigate the performance of a set of shrinkage based covariance estimators within ISEM. The proposed method is successfully applied on several nonlinear parameter estimation problems for subsurface flow models. The efficiency of the proposed algorithm is demonstrated by the small size of utilized ensembles and in terms of error convergence rates

An iterative stochastic ensemble method for parameter estimation of subsurface flow models

KAUST Repository

Elsheikh, Ahmed H.

2013-06-01

Parameter estimation for subsurface flow models is an essential step for maximizing the value of numerical simulations for future prediction and the development of effective control strategies. We propose the iterative stochastic ensemble method (ISEM) as a general method for parameter estimation based on stochastic estimation of gradients using an ensemble of directional derivatives. ISEM eliminates the need for adjoint coding and deals with the numerical simulator as a blackbox. The proposed method employs directional derivatives within a Gauss-Newton iteration. The update equation in ISEM resembles the update step in ensemble Kalman filter, however the inverse of the output covariance matrix in ISEM is regularized using standard truncated singular value decomposition or Tikhonov regularization. We also investigate the performance of a set of shrinkage based covariance estimators within ISEM. The proposed method is successfully applied on several nonlinear parameter estimation problems for subsurface flow models. The efficiency of the proposed algorithm is demonstrated by the small size of utilized ensembles and in terms of error convergence rates. © 2013 Elsevier Inc.

Calcium silicate structure and carbonation shrinkage of a tobermorite-based material

International Nuclear Information System (INIS)

Matsushita, Fumiaki; Aono, Yoshimichi; Shibata, Sumio

2004-01-01

Carbonated autoclaved aerated concretes (AACs) show no shrinkage at a degree of carbonation approximately less than 20%. The 29 Si MAS NMR spectrum showed that at a degree of carbonation less than 25%, the typical double-chain silicate anion structure of tobermorite-11A was well maintained and interlayer Ca ions were exchanged with protons. This corresponded to the absence of carbonation shrinkage at a degree of carbonation less than 20%. When the degree of carbonation increased from 25% to 50% up to 60%, the double-chain silicate anion structure of tobermorite-11A was decomposed and Ca ions in the Ca-O layers were dissolved, showing a possible mechanism of carbonation shrinkage

ITER convertible blanket evaluation

International Nuclear Information System (INIS)

Wong, C.P.C.; Cheng, E.

1995-01-01

Proposed International Thermonuclear Experimental Reactor (ITER) convertible blankets were reviewed. Key design difficulties were identified. A new particle filter concept is introduced and key performance parameters estimated. Results show that this particle filter concept can satisfy all of the convertible blanket design requirements except the generic issue of Be blanket lifetime. If the convertible blanket is an acceptable approach for ITER operation, this particle filter option should be a strong candidate

ITER licensing

International Nuclear Information System (INIS)

Gordon, C.W.

2005-01-01

ITER was fortunate to have four countries interested in ITER siting to the point where licensing discussions were initiated. This experience uncovered the challenges of licensing a first of a kind, fusion machine under different licensing regimes and helped prepare the way for the site specific licensing process. These initial steps in licensing ITER have allowed for refining the safety case and provide confidence that the design and safety approach will be licensable. With site-specific licensing underway, the necessary regulatory submissions have been defined and are well on the way to being completed. Of course, there is still work to be done and details to be sorted out. However, the informal international discussions to bring both the proponent and regulatory authority up to a common level of understanding have laid the foundation for a licensing process that should proceed smoothly. This paper provides observations from the perspective of the International Team. (author)

Astrocytic mechanisms explaining neural-activity-induced shrinkage of extraneuronal space.

Directory of Open Access Journals (Sweden)

Ivar Østby

2009-01-01

Full Text Available Neuronal stimulation causes approximately 30% shrinkage of the extracellular space (ECS between neurons and surrounding astrocytes in grey and white matter under experimental conditions. Despite its possible implications for a proper understanding of basic aspects of potassium clearance and astrocyte function, the phenomenon remains unexplained. Here we present a dynamic model that accounts for current experimental data related to the shrinkage phenomenon in wild-type as well as in gene knockout individuals. We find that neuronal release of potassium and uptake of sodium during stimulation, astrocyte uptake of potassium, sodium, and chloride in passive channels, action of the Na/K/ATPase pump, and osmotically driven transport of water through the astrocyte membrane together seem sufficient for generating ECS shrinkage as such. However, when taking into account ECS and astrocyte ion concentrations observed in connection with neuronal stimulation, the actions of the Na(+/K(+/Cl(- (NKCC1 and the Na(+/HCO(3 (- (NBC cotransporters appear to be critical determinants for achieving observed quantitative levels of ECS shrinkage. Considering the current state of knowledge, the model framework appears sufficiently detailed and constrained to guide future key experiments and pave the way for more comprehensive astroglia-neuron interaction models for normal as well as pathophysiological situations.

Iterative approach to effective interactions in nuclei

International Nuclear Information System (INIS)

Heiss, W.D.

1982-01-01

Starting from a non-linear equation for the effective interaction in a model space, various iteration procedures converge to a correct solution irrespective of the presence of intruder states. The physical significance of the procedures and the respective solution is discussed

ITER...ation

International Nuclear Information System (INIS)

Troyon, F.

1997-01-01

Recurrent attacks against ITER, the new generation of tokamak are a mix of political and scientific arguments. This short article draws a historical review of the European fusion program. This program has allowed to build and manage several installations in the aim of getting experimental results necessary to lead the program forwards. ITER will bring together a fusion reactor core with technologies such as materials, superconductive coils, heating devices and instrumentation in order to validate and delimit the operating range. ITER will be a logical and decisive step towards the use of controlled fusion. (A.C.)

Shrinkage modeling of concrete reinforced by palm fibres in hot dry environments

Science.gov (United States)

Akchiche, Hamida; Kriker, Abdelouahed

2017-02-01

The cement materials, such as concrete and conventional mortar present very little resistance to traction and cracking, these hydraulic materials which induces large withdrawals on materials and cracks in structures. The hot dry environments such as: the Saharan regions of Algeria, Indeed, concrete structures in these regions are very fragile, and present high shrinkage. Strengthening of these materials by fibers can provide technical solutions for improving the mechanical performance. The aim of this study is firstly, to reduce the shrinkage of conventional concrete with its reinforcement with date palm fibers. In fact, Algeria has an extraordinary resources in natural fibers (from Palm, Abaca, Hemp) but without valorization in practical areas, especially in building materials. Secondly, to model the shrinkage behavior of concrete was reinforced by date palm fibers. In the literature, several models for still fiber concrete were founded but few are offers for natural fiber concretes. To do so, a still fiber concretes model of YOUNG - CHERN was used. According to the results, a reduction of shrinkage with reinforcement by date palm fibers was showed. A good ability of molding of shrinkage of date palm reinforced concrete with YOUNG - CHERN Modified model was obtained. In fact, a good correlation between experimental data and the model data was recorded.

ITER Remote Maintenance System (IRMS) lifecycle management

Energy Technology Data Exchange (ETDEWEB)

Tesini, Alessandro, E-mail: alessandro.tesini@iter.org [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Otto' , Bede [Oxford Technologies Ltd, 7, Nuffield Way, Abingdon, Oxon OX14 1RJ (United Kingdom); Blight, John [FAAST 31c Allee de la Granette, 13600 Ceyreste (France); Choi, Chang-Hwan; Friconneau, Jean-Pierre; Gotewal, Krishan Kumar; Hamilton, David [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Heckendorn, Frank [FD Technologies, PO Box 6686, Aiken, SC (United States); Martins, Jean-Pierre [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Marty, Thomas [Westinghouse, 122, avenue de Hambourg, 13008 Marseille (France); Nakahira, Masataka; Palmer, Jim; Subramanian, Rajendran [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

2011-10-15

The availability of the ITER machine to perform its scientific program is strongly dependent on the performance of the different Remote Handling (RH) systems constituting the ITER Remote Maintenance System (IRMS). The lifecycle of the IRMS will largely exceed 40 years from initial concept design and proof testing through to machine decommissioning. Such a long lifecycle requires that a rigorous approach is put in place to guarantee the technical capabilities of the highly innovative IRMS, its efficiency and its availability. For this purpose, an IRMS System Engineering and IRMS lifecycle management approach has been adopted by ITER. The approach aims at ensuring the IRMS full operability and availability at an acceptable cost of ownership over the full ITER machine assembly and operations period. The IRMS lifecycle management method described in this paper covers such subjects as specific requirements for IRMS design reviews, monitoring during manufacture, factory and site acceptance testing, integrated commissioning, decontamination, maintenance and re-qualification strategies, requirements for Integrated Logistical Support during operations. The updating and implementation of the IRMS lifecycle strategy and this procedure will be managed and monitored by the Remote Handling Integrated Product Team (RH-IPT). Although developed for the IRMS, the basic principles and procedures of lifecycle management could be applied to other ITER plant systems whose reliability and availability will be essential for the continued operation of the ITER machine.

ITER Remote Maintenance System (IRMS) lifecycle management

International Nuclear Information System (INIS)

Tesini, Alessandro; Otto', Bede; Blight, John; Choi, Chang-Hwan; Friconneau, Jean-Pierre; Gotewal, Krishan Kumar; Hamilton, David; Heckendorn, Frank; Martins, Jean-Pierre; Marty, Thomas; Nakahira, Masataka; Palmer, Jim; Subramanian, Rajendran

2011-01-01

The availability of the ITER machine to perform its scientific program is strongly dependent on the performance of the different Remote Handling (RH) systems constituting the ITER Remote Maintenance System (IRMS). The lifecycle of the IRMS will largely exceed 40 years from initial concept design and proof testing through to machine decommissioning. Such a long lifecycle requires that a rigorous approach is put in place to guarantee the technical capabilities of the highly innovative IRMS, its efficiency and its availability. For this purpose, an IRMS System Engineering and IRMS lifecycle management approach has been adopted by ITER. The approach aims at ensuring the IRMS full operability and availability at an acceptable cost of ownership over the full ITER machine assembly and operations period. The IRMS lifecycle management method described in this paper covers such subjects as specific requirements for IRMS design reviews, monitoring during manufacture, factory and site acceptance testing, integrated commissioning, decontamination, maintenance and re-qualification strategies, requirements for Integrated Logistical Support during operations. The updating and implementation of the IRMS lifecycle strategy and this procedure will be managed and monitored by the Remote Handling Integrated Product Team (RH-IPT). Although developed for the IRMS, the basic principles and procedures of lifecycle management could be applied to other ITER plant systems whose reliability and availability will be essential for the continued operation of the ITER machine.

A break-even analysis of RFID technology for inventory sensitive to shrinkage

NARCIS (Netherlands)

Kok, de A.G.; Donselaar, van K.H.; Woensel, van T.

2008-01-01

By embedding RFID tags onto their products, both manufacturers and retailers try to control for shrinkage (e.g. due to theft). Current inventory control systems do not take into account the disappearing inventory due to this shrinkage. As a response, corrective actions are made by performing costly

Study of SEM preparation artefacts with correlative microscopy: Cell shrinkage of adherent cells by HMDS-drying.

Science.gov (United States)

Katsen-Globa, Alisa; Puetz, Norbert; Gepp, Michael M; Neubauer, Julia C; Zimmermann, Heiko

2016-11-01

One of the often reported artefacts during cell preparation to scanning electron microscopy (SEM) is the shrinkage of cellular objects, that mostly occurs at a certain time-dependent stage of cell drying. Various methods of drying for SEM, such as critical point drying, freeze-drying, as well as hexamethyldisilazane (HMDS)-drying, were usually used. The latter becomes popular since it is a low cost and fast method. However, the correlation of drying duration and real shrinkage of objects was not investigated yet. In this paper, cell shrinkage at each stage of preparation for SEM was studied. We introduce a shrinkage coefficient using correlative light microscopy (LM) and SEM of the same human mesenchymal stem cells (hMSCs). The influence of HMDS-drying duration on the cell shrinkage is shown: the longer drying duration, the more shrinkage is observed. Furthermore, it was demonstrated that cell shrinkage is inversely proportional to cultivation time: the longer cultivation time, the more cell spreading area and the less cell shrinkage. Our results can be applicable for an exact SEM quantification of cell size and determination of cell spreading area in engineering of artificial cellular environments using biomaterials. SCANNING 38:625-633, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Alara applied to iter design and operation

International Nuclear Information System (INIS)

Uzan-Elbez, Joelle; Rodriguez-Rodrigo, Lina; Porfiri, Maria Teresa; Taylor, Neil; Gordon, Charles; Garin, Pascal; Girard, Jean-Philippe

2005-01-01

Based on the existing data on ITER and the safety options for licensing ITER in Cadarache, the present work assesses the application of the as-low-as-reasonably-achievable (ALARA) principle, as it has been implemented in the design of ITER and will be applied during ITER operation, as well as the compliance of the design with EUR/96-29 directive and regulation applicable in France. The preliminary occupational radiation exposure estimate gives a value of about 250 man mSv/a, which is half the annual target for ITER and comes essentially from maintenance activities. Some examples of the approach are presented

Shrinkage Analysis on Thick Plate Part using Response Surface Methodology (RSM

Directory of Open Access Journals (Sweden)

Isafiq M.

2016-01-01

Full Text Available The work reported herein is about an analysis on the quality (shrinkage on a thick plate part using Response Surface Methodology (RSM. Previous researches showed that the most influential factor affecting the shrinkage on moulded parts are mould and melt temperature. Autodesk Moldflow Insight software was used for the analysis, while specifications of Nessei NEX 1000 injection moulding machine and P20 mould material were incorporated in this study on top of Acrylonitrile Butadiene Styrene (ABS as a moulded thermoplastic material. Mould temperature, melt temperature, packing pressure and packing time were selected as variable parameters. The results show that the shrinkage have improved 42.48% and 14.41% in parallel and normal directions respectively after the optimisation process.

Fire risk analysis in ITER tritium building

International Nuclear Information System (INIS)

Lignini, Franck; Uzan-Elbez, Joelle; Girard, Jean-Philippe; Porfiri, Maria Teresa; Rodriguez-Rodrigo, Lina

2005-01-01

Events, such as fire, have been considered in ITER documentation of low probability and a general approach has been defined in [Technical basis for the ITER final design, EDA Documentation Series I, No. 22, IAEA, Vienna, 2001] to be developed later for the ITER specific site. It was said that 'these hazards will be treated according to the industrial safety regulations and practices of the host country'. In the framework of studies for the European ITER site in Cadarache, an assessment of fire hazard has been done in order to ensure compliance with French safety requirements. In this report, a summary of existing laws is presented and an example of the deterministic approach to be followed for the preliminary safety report (PSR) is given on the analysis of tritium building design

Improved estimation of subject-level functional connectivity using full and partial correlation with empirical Bayes shrinkage.

Science.gov (United States)

Mejia, Amanda F; Nebel, Mary Beth; Barber, Anita D; Choe, Ann S; Pekar, James J; Caffo, Brian S; Lindquist, Martin A

2018-05-15

Reliability of subject-level resting-state functional connectivity (FC) is determined in part by the statistical techniques employed in its estimation. Methods that pool information across subjects to inform estimation of subject-level effects (e.g., Bayesian approaches) have been shown to enhance reliability of subject-level FC. However, fully Bayesian approaches are computationally demanding, while empirical Bayesian approaches typically rely on using repeated measures to estimate the variance components in the model. Here, we avoid the need for repeated measures by proposing a novel measurement error model for FC describing the different sources of variance and error, which we use to perform empirical Bayes shrinkage of subject-level FC towards the group average. In addition, since the traditional intra-class correlation coefficient (ICC) is inappropriate for biased estimates, we propose a new reliability measure denoted the mean squared error intra-class correlation coefficient (ICC MSE ) to properly assess the reliability of the resulting (biased) estimates. We apply the proposed techniques to test-retest resting-state fMRI data on 461 subjects from the Human Connectome Project to estimate connectivity between 100 regions identified through independent components analysis (ICA). We consider both correlation and partial correlation as the measure of FC and assess the benefit of shrinkage for each measure, as well as the effects of scan duration. We find that shrinkage estimates of subject-level FC exhibit substantially greater reliability than traditional estimates across various scan durations, even for the most reliable connections and regardless of connectivity measure. Additionally, we find partial correlation reliability to be highly sensitive to the choice of penalty term, and to be generally worse than that of full correlations except for certain connections and a narrow range of penalty values. This suggests that the penalty needs to be chosen carefully

PREDIKSI SHRINKAGE UNTUK MENGHINDARI CACAT PRODUK PADA PLASTIC INJECTION

Directory of Open Access Journals (Sweden)

Agus Dwi Anggono

2015-05-01

Full Text Available Plastic injection merupakan proses manufactur untuk membuat produk dengan bahan dasar plastic atau dalam kesempatan ini polypropylene. Pada proses tersebut seringkali terjadi cacat produk seperti pengerutan, retak, dimensi tidak sesuai dan kerusakan saat produk keluar dari mould, sehingga banyak material yang terbuang percuma. Meskipun cacat produk tersebut dipengaruhi banyak factor, tetapi yang paling utama adalah masalah shrinkage, atau penyusutan material setelah terjadi pendinginan. Sangat penting untuk melakukan prediksi lebih awal terjadinya penyusutan setelah pendinginan untuk menghindari cacat produk. Dalam penelitian ini akan dilakukan prediksi shrinkage yang akan digunakan untuk material polypropylene dengan cara perhitungan standar. Pembuatan modeling dalam bentuk 3D (tiga dimensi injection molding baik cavity maupun corenya dengan menggunakan CATIA, kemudian dilakukan analisis dengan software MoldFlow untuk pembuatan mesh dan memberikan batasan panas pada komponen sehingga dapat diketahui mode penyusutannya. Analisis ini akan memberikan gambaran tentang distribusi panas pada mould dan memberikan tentang gambaran aliran fluida. Pada analisis tersebut dapat dilihat gejala terjadinya cacat produk, jika hal itu terjadi maka perlu dilakukan perubahan shrinkage, sampai diperoleh hasil analisis yang baik.

Layout compliance for triple patterning lithography: an iterative approach

Science.gov (United States)

Yu, Bei; Garreton, Gilda; Pan, David Z.

2014-10-01

As the semiconductor process further scales down, the industry encounters many lithography-related issues. In the 14nm logic node and beyond, triple patterning lithography (TPL) is one of the most promising techniques for Metal1 layer and possibly Via0 layer. As one of the most challenging problems in TPL, recently layout decomposition efforts have received more attention from both industry and academia. Ideally the decomposer should point out locations in the layout that are not triple patterning decomposable and therefore manual intervention by designers is required. A traditional decomposition flow would be an iterative process, where each iteration consists of an automatic layout decomposition step and manual layout modification task. However, due to the NP-hardness of triple patterning layout decomposition, automatic full chip level layout decomposition requires long computational time and therefore design closure issues continue to linger around in the traditional flow. Challenged by this issue, we present a novel incremental layout decomposition framework to facilitate accelerated iterative decomposition. In the first iteration, our decomposer not only points out all conflicts, but also provides the suggestions to fix them. After the layout modification, instead of solving the full chip problem from scratch, our decomposer can provide a quick solution for a selected portion of layout. We believe this framework is efficient, in terms of performance and designer friendly.

US power outage won't dim ITER

International Nuclear Information System (INIS)

Lawler, A.

1996-01-01

The $8 billion International Thermonuclear Experimental Reactor (ITER) is moving ahead, without definite support of the USA. However, still undecided are where it will be built and how much each partner will pay. This article discusses the international political aspects of building the ITER, with a particular emphasis on the Japanese approach to landing the ITER. Also discussed are possible cost-saving solutions

Effect of steel fibers on plastic shrinkage cracking of normal and high strength concretes

Directory of Open Access Journals (Sweden)

Özgür Eren

2010-06-01

Full Text Available Naturally concrete shrinks when it is subjected to a drying environment. If this shrinkage is restrained, tensile stresses develop and concrete may crack. Plastic shrinkage cracks are especially harmful on slabs. One of the methods to reduce the adverse effects of shrinkage cracking of concrete is by reinforcing concrete with short randomly distributed fibers. The main objective of this study was to investigate the effect of fiber volume and aspect ratio of hooked steel fibers on plastic shrinkage cracking behavior together with some other properties of concrete. In this research two different compressive strength levels namely 56 and 73 MPa were studied. Concretes were produced by adding steel fibers of 3 different volumes of 3 different aspect ratios. From this research study, it is observed that steel fibers can significantly reduce plastic shrinkage cracking behavior of concretes. On the other hand, it was observed that these steel fibers can adversely affect some other properties of concrete during fresh and hardened states.

Drying Shrinkage Behaviour of Fibre Reinforced Concrete Incorporating Polyvinyl Alcohol Fibres and Fly Ash

Directory of Open Access Journals (Sweden)

Amin Noushini

2014-01-01

Full Text Available The current study assesses the drying shrinkage behaviour of polyvinyl alcohol fibre reinforced concrete (PVA-FRC containing short-length (6 mm and long-length (12 mm uncoated monofilament PVA fibres at 0.125%, 0.25%, 0.375%, and 0.5% volumetric fractions. Fly ash is also used as a partial replacement of Portland cement in all mixes. PVA-FRC mixes have been compared to length change of control concrete (devoid of fibres at 3 storage intervals: early-age (0–7 days, short-term (0–28 days, and long-term (28–112 days intervals. The shrinkage results of FRC and control concrete up to 112 days indicated that all PVA-FRC mixes exhibited higher drying shrinkage than control. The shrinkage exhibited by PVA-FRC mixes ranged from 449 to 480 microstrain, where this value was only 427 microstrain in the case of control. In addition, the longer fibres exhibited higher mass loss, thus potentially contributing to higher shrinkage.

The Shrinkage Cracking Behavior in Reinforced Reactive Powder Concrete Walls

Directory of Open Access Journals (Sweden)

Samir A. Al-Mashhadi

2017-07-01

Full Text Available In this study, the reduced scale wall models were used (they are believed to resemble as much as possible the field conditions to study the shrinkage behavior of reactive powder concrete (RPC base restrained walls. Six base restrained RPC walls were casted in different length/height ratios of two ratios of steel fiber by volume in Summer. These walls were restrained by reinforced concrete bases to provide the continuous base restraint to the walls. The mechanical properties of reactive powder concrete investigated were; compressive strength between (75.3 – 140.1 MPa, splitting tensile strength between (5.7 – 13.9 MPa, flexural tensile strength (7.7 – 24.5 MPa, and static modulus of elasticity (32.7 – 47.1GPa. Based on the observations of this work, it was found that the cracks did not develop in the reduced scale of the reactive powder concrete (RPC walls restrained from movement at their bases for different L/H ratios (2, 5, and 10 and for two ratio of steel fiber (1% & 2% during 90 days period of drying conditions. Moreover, the shrinkage values increase toward the edges. Based on the results of this work, the increase in the maximum shrinkage values of walls with 1% steel fiber were (29%, 28%, 28% of the maximum shrinkage values of walls with 2% steel fiber of length/height ratios of (2, 5, and 10 respectively. The experimental observation in beam specimens showed that the free shrinkage, tensile strain capacity and elastic tensile strain capacity (at date of cracking of beams with 1% steel fiber were higher than the beams with 2% steel fiber by about (24%, (45% and (42% respectively

The influence of superabsorbent polymers on the autogenous shrinkage properties of cement pastes with supplementary cementitious materials

DEFF Research Database (Denmark)

Snoeck, D.; Jensen, Ole Mejlhede; De Belie, N.

2015-01-01

Fly ash and blast-furnace slag containing binders are frequently used in the construction industry and it is important to know the extent of autogenous shrinkage and its (ideal) mitigation by superabsorbent polymers in these systems as a function of their age. In this paper, the autogenous...... shrinkage was determined by manual and automated shrinkage measurements. Autogenous shrinkage was reduced in cement pastes with the supplementary cementitious materials versus Portland cement pastes. At later ages, the rate of autogenous shrinkage is higher due to the pozzolanic activity. Internal curing...

The ITER remote maintenance system

International Nuclear Information System (INIS)

Tesini, A.; Palmer, J.

2008-01-01

The aim of this paper is to summarize the ITER approach to machine components maintenance. A major objective of the ITER project is to demonstrate that a future power producing fusion device can be maintained effectively and offer practical levels of plant availability. During its operational lifetime, many systems of the ITER machine will require maintenance and modification; this can be achieved using remote handling methods. The need for timely, safe and effective remote operations on a machine as complex as ITER and within one of the world's most hostile remote handling environments represents a major challenge at every level of the ITER Project organization, engineering and technology. The basic principles of fusion reactor maintenance are presented. An updated description of the ITER remote maintenance system is provided. This includes the maintenance equipment used inside the vacuum vessel, inside the hot cell and the hot cell itself. The correlation between the functions of the remote handling equipment, of the hot cell and of the radwaste processing system is also described. The paper concludes that ITER has equipped itself with a good platform to tackle the challenges presented by its own maintenance and upgrade needs

TH-E-BRF-01: Exploiting Tumor Shrinkage in Split-Course Radiotherapy

International Nuclear Information System (INIS)

Unkelbach, J; Craft, D; Hong, T; Papp, D; Wolfgang, J; Bortfeld, T; Ramakrishnan, J; Salari, E

2014-01-01

Purpose: In split-course radiotherapy, a patient is treated in several stages separated by weeks or months. This regimen has been motivated by radiobiological considerations. However, using modern image-guidance, it also provides an approach to reduce normal tissue dose by exploiting tumor shrinkage. In this work, we consider the optimal design of split-course treatments, motivated by the clinical management of large liver tumors for which normal liver dose constraints prohibit the administration of an ablative radiation dose in a single treatment. Methods: We introduce a dynamic tumor model that incorporates three factors: radiation induced cell kill, tumor shrinkage, and tumor cell repopulation. The design of splitcourse radiotherapy is formulated as a mathematical optimization problem in which the total dose to the liver is minimized, subject to delivering the prescribed dose to the tumor. Based on the model, we gain insight into the optimal administration of radiation over time, i.e. the optimal treatment gaps and dose levels. Results: We analyze treatments consisting of two stages in detail. The analysis confirms the intuition that the second stage should be delivered just before the tumor size reaches a minimum and repopulation overcompensates shrinking. Furthermore, it was found that, for a large range of model parameters, approximately one third of the dose should be delivered in the first stage. The projected benefit of split-course treatments in terms of liver sparing depends on model assumptions. However, the model predicts large liver dose reductions by more than a factor of two for plausible model parameters. Conclusion: The analysis of the tumor model suggests that substantial reduction in normal tissue dose can be achieved by exploiting tumor shrinkage via an optimal design of multi-stage treatments. This suggests taking a fresh look at split-course radiotherapy for selected disease sites where substantial tumor regression translates into reduced

TH-E-BRF-01: Exploiting Tumor Shrinkage in Split-Course Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Unkelbach, J; Craft, D; Hong, T; Papp, D; Wolfgang, J; Bortfeld, T [Massachusetts General Hospital, Boston, MA (United States); Ramakrishnan, J [University of Wisconsin, Madison, Wisconsin (United States); Salari, E [Wichita State University, Wichita, KS (United States)

2014-06-15

Purpose: In split-course radiotherapy, a patient is treated in several stages separated by weeks or months. This regimen has been motivated by radiobiological considerations. However, using modern image-guidance, it also provides an approach to reduce normal tissue dose by exploiting tumor shrinkage. In this work, we consider the optimal design of split-course treatments, motivated by the clinical management of large liver tumors for which normal liver dose constraints prohibit the administration of an ablative radiation dose in a single treatment. Methods: We introduce a dynamic tumor model that incorporates three factors: radiation induced cell kill, tumor shrinkage, and tumor cell repopulation. The design of splitcourse radiotherapy is formulated as a mathematical optimization problem in which the total dose to the liver is minimized, subject to delivering the prescribed dose to the tumor. Based on the model, we gain insight into the optimal administration of radiation over time, i.e. the optimal treatment gaps and dose levels. Results: We analyze treatments consisting of two stages in detail. The analysis confirms the intuition that the second stage should be delivered just before the tumor size reaches a minimum and repopulation overcompensates shrinking. Furthermore, it was found that, for a large range of model parameters, approximately one third of the dose should be delivered in the first stage. The projected benefit of split-course treatments in terms of liver sparing depends on model assumptions. However, the model predicts large liver dose reductions by more than a factor of two for plausible model parameters. Conclusion: The analysis of the tumor model suggests that substantial reduction in normal tissue dose can be achieved by exploiting tumor shrinkage via an optimal design of multi-stage treatments. This suggests taking a fresh look at split-course radiotherapy for selected disease sites where substantial tumor regression translates into reduced

Shrinkage-reducing admixtures and early-age desiccation in cement pastes and mortars

DEFF Research Database (Denmark)

Bentz, D. P.; Geiker, Mette Rica; Hansen, Kurt Kielsgaard

2001-01-01

Fundamental studies of the early-age desiccation of cement-based materials with and without a shrinkage-reducing admixture (SRA) have been performed. Studies have been conducted under both sealed and drying conditions. Physical measurements include mass loss, surface tension, X-ray absorption to ...... to low w/c ratio concretes undergoing self-desiccation, in addition to their normal usage to reduce drying shrinkage.......Fundamental studies of the early-age desiccation of cement-based materials with and without a shrinkage-reducing admixture (SRA) have been performed. Studies have been conducted under both sealed and drying conditions. Physical measurements include mass loss, surface tension, X-ray absorption...

Effects of Shrinkage Reducing Agent and Expansive Admixture on the Volume Deformation of Ultrahigh Performance Concrete

OpenAIRE

Anshuang, Su; Ling, Qin; Shoujie, Zhang; Jiayang, Zhang; Zhaoyu, Li

2017-01-01

This paper investigated the influences of shrinkage reducing agent and expansive admixture on autogenous and drying shrinkage of ultrahigh performance concrete (UHPC) containing antifoaming admixture. The shrinkage reducing agent was used at dosage of 0.5%, 1%, and 2% and the expansive admixture was used at dosage of 2% to 4% by mass of cementitious material. The results show that the air content of UHPC increases with the higher addition of shrinkage reducing agent and expansive admixtures. ...

The effect of mucosal cuff shrinkage around dental implants during healing abutment replacement.

Science.gov (United States)

Nissan, J; Zenziper, E; Rosner, O; Kolerman, R; Chaushu, L; Chaushu, G

2015-10-01

Soft tissue shrinkage during the course of restoring dental implants may result in biological and prosthodontic difficulties. This study was conducted to measure the continuous shrinkage of the mucosal cuff around dental implants following the removal of the healing abutment up to 60 s. Individuals treated with implant-supported fixed partial dentures were included. Implant data--location, type, length, diameter and healing abutments' dimensions--were recorded. Mucosal cuff shrinkage, following removal of the healing abutments, was measured in bucco-lingual direction at four time points--immediately after 20, 40 and 60 s. anova was used to for statistical analysis. Eighty-seven patients (49 women and 38 men) with a total of 311 implants were evaluated (120 maxilla; 191 mandible; 291 posterior segments; 20 anterior segments). Two-hundred and five (66%) implants displayed thick and 106 (34%) thin gingival biotype. Time was the sole statistically significant parameter affecting mucosal cuff shrinkage around dental implants (P < 0.001). From time 0 to 20, 40 and 60 s, the mean diameter changed from 4.1 to 4.07, 3.4 and 2.81 mm, respectively. The shrinkage was 1%, 17% and 31%, respectively. The gingival biotype had no statistically significant influence on mucosal cuff shrinkage (P = 0.672). Time required replacing a healing abutment with a prosthetic element should be minimised (up to 20/40 s), to avoid pain, discomfort and misfit. © 2015 John Wiley & Sons Ltd.

A generalized DEMATEL theory with a shrinkage coefficient for an indirect relation matrix

Directory of Open Access Journals (Sweden)

Liu Hsiang-Chuan

2017-01-01

Full Text Available In this paper, a novel decision-making trial and evaluation laboratory (DEMATEL theory with a shrinkage coefficient of indirect relation matrix is proposed, and a useful validity index, called Liu’s validity index, is also proposed for evaluating the performance of any DEMATEL model. If the shrinkage coefficient of an indirect relation matrix is equal to 1, then this new theory is identical to the traditional theory; in other words, it is a generalization of the traditional theory. Furthermore, the indirect relation is always considerably greater than the direct one in traditional DEMATEL theory, which is unreasonable and unfair because it overemphasizes the influence of the indirect relation. We prove in this paper that if the shrinkage coefficient is equal to 0.5, then the indirect relation is less than its direct relation. Because the shrinkage coefficient belongs to [0.5, 1], according to Liu’s validity index, we can find a more appropriate shrinkage coefficient to obtain a more efficient DEMATEL method. Some crucial properties of this new theory are discussed, and a simple example is provided to illustrate the advantages of the proposed theory.

DH and ESPI laser interferometry applied to the restoration shrinkage assessment

International Nuclear Information System (INIS)

Campos, L.M.P.; Parra, D.F.; Vasconcelos, M.R.; Vaz, M.; Monteiro, J.

2014-01-01

In dental restoration postoperative marginal leakage is commonly associated to polymerization shrinkage effects. In consequence the longevity and quality of restorative treatment depends on the shrinkage mechanisms of the composite filling during the polymerization. In this work the development of new techniques for evaluation of those effects under light-induced polymerization of dental nano composite fillings is reported. The composite resins activated by visible light, initiate the polymerization process by absorbing light in wavelengths at about 470 nm. The techniques employed in the contraction assessment were digital holography (DH) and Electronic Speckle Pattern Interferometry (ESPI) based on laser interferometry. A satisfactory resolution was achieved in the non-contact displacement field measurements on small objects concerning the experimental dental samples. According to a specific clinical protocol, natural teeth were used (human mandibular premolars). A class I cavity was drilled and restored with nano composite material, according to Black principles. The polymerization was monitored by DH and ESPI in real time during the cure reaction of the restoration. The total displacement reported for the material in relation of the tooth wall was 3.7 μm (natural tooth). The technique showed the entire tooth surface (wall) deforming during polymerization shrinkage. - Highlights: • Both of holographic techniques were able to measure the polymerization shrinkage. • The entire tooth surface was deformed during the polymerization shrinkage. • The group with greater percentage of filler showed the lowest value of deformation. • The values of displacement ranged from 0.9 to 3.4 μm

C-O-H-S magmatic fluid system in shrinkage bubbles of melt inclusions

Science.gov (United States)

Robidoux, P.; Frezzotti, M. L.; Hauri, E. H.; Aiuppa, A.

2016-12-01

Magmatic volatiles include multiple phases in the C-O-H-S system of shrinkage bubbles for which a conceptual model is still unclear during melt inclusion formation [1,2,3,4]. The present study aims to qualitatively explore the evolution of the volatile migration, during and after the formation of the shrinkage bubble in melt inclusions trapped by olivines from Holocene to present at San Cristóbal volcano (Nicaragua), Central American Volcanic Arc (CAVA). Combined scanning electron microscope (SEM) and Raman spectroscopy observations allow to define the mineral-fluid phases inside typical shrinkage bubbles at ambient temperature. The existence of residual liquid water is demonstrated in the shrinkage bubbles of naturally quenched melt inclusion and this water could represents the principal agent for chemical reactions with other dissolved ionic species (SO42-, CO32-, etc.) and major elements (Mg, Fe, Cu, etc.) [4,5]. With the objective of following the cooling story of the bubble-inclusion system, the new methodological approach here estimate the interval of equilibrium temperatures for each SEM-Raman identified mineral phase (carbonates, hydrous carbonates, sulfurs, sulfates, etc.). Finally, two distinct mechanisms are proposed to describe the evolution of this heterogeneous fluid system in bubble samples at San Cristóbal which imply a close re-examination for similar volcanoes in subduction zone settings: (1) bubbles are already contracted and filled by volatiles by diffusion processes from the glass and leading to a C-O-H-S fluid-glass reaction enriched in Mg-Fe-Cu elements (2) bubbles are formed by oversaturation of the volatiles from the magma which is producing an immiscible metal-rich fluid. [1]Moore et al. (2015). Am. Mineral. 100, 806-823 [2]Wallace et al. (2015). Am. Mineral. 100, 787-794 [3]Lowenstern (2015). Am. Mineral. 100, 672-673 [4]Esposito, et al. (2016). Am. Mineral. 101, 1691-1708 [5]Kamenetsky et al. (2001). Earth Planet. Sci. Lett. 184, 685-702

Iterative perceptual learning for social behavior synthesis

NARCIS (Netherlands)

de Kok, I.A.; Poppe, Ronald Walter; Heylen, Dirk K.J.

We introduce Iterative Perceptual Learning (IPL), a novel approach to learn computational models for social behavior synthesis from corpora of human–human interactions. IPL combines perceptual evaluation with iterative model refinement. Human observers rate the appropriateness of synthesized

Effectiveness of shrinkage-reducing admixtures on Portland pozzolan cement concrete

Directory of Open Access Journals (Sweden)

Videla, C.

2005-06-01

Full Text Available Drying shrinkage causes tensile stress in restrained concrete members. Since all structural elements are subject to some degree of restraint, drying shrinkage is regarded to be one of the main causes of concrete cracking. The purpose of the present study was to evaluate the effectiveness of SRA in reducing drying shrinkage strain in Portland pozzolan cement concrete. The major variables examined included slump, admixture type and dose, and specimen size. The measured results indicate that any of the admixtures used in the study significantly reduced shrinkage. Concrete manufactured with shrinkage reducing admixtures shrank an average of 43% less than concrete without admixtures. As a rule, the higher the dose of admixture, the higher was its shrinkage reduction performance. The experimental results were compared to the shrinkage strain estimated with the ACI 209, CEB MC 90, B3, GL 2000, Sakata 1993 and Sakata 2001 models. Although none of these models was observed to accurately describe the behaviour of Portland pozzolan cement concrete with shrinkage reducing admixtures, the Sakata 2001 model, with a weighted coefficient of variation of under 30%, may be regarded to be roughly adequate.

La retracción por secado es un fenómeno intrínseco del hormigón que produce tensiones de tracción en elementos restringidos de hormigón. Puesto que todos los elementos presentan algún grado de retracción, se considera a la retracción por secado como una de las principales causas de agrietamiento en proyectos de construcción en hormigón. Por lo tanto, el objetivo de esta investigación fue evaluar la efectividad de los aditivos reductores de retracción (SRA en hormigones fabricados con cemento Portland puzolánico. Las variables principales estudiadas incluyen el asentamiento de cono de Abrams, marca y dosis de aditivo reductor de retracción, y tamaño de espécimen de hormigón. Los resultados obtenidos permiten concluir que el uso de

Regression tools for CO2 inversions: application of a shrinkage estimator to process attribution

International Nuclear Information System (INIS)

Shaby, Benjamin A.; Field, Christopher B.

2006-01-01

In this study we perform an atmospheric inversion based on a shrinkage estimator. This method is used to estimate surface fluxes of CO 2 , first partitioned according to constituent geographic regions, and then according to constituent processes that are responsible for the total flux. Our approach differs from previous approaches in two important ways. The first is that the technique of linear Bayesian inversion is recast as a regression problem. Seen as such, standard regression tools are employed to analyse and reduce errors in the resultant estimates. A shrinkage estimator, which combines standard ridge regression with the linear 'Bayesian inversion' model, is introduced. This method introduces additional bias into the model with the aim of reducing variance such that errors are decreased overall. Compared with standard linear Bayesian inversion, the ridge technique seems to reduce both flux estimation errors and prediction errors. The second divergence from previous studies is that instead of dividing the world into geographically distinct regions and estimating the CO 2 flux in each region, the flux space is divided conceptually into processes that contribute to the total global flux. Formulating the problem in this manner adds to the interpretability of the resultant estimates and attempts to shed light on the problem of attributing sources and sinks to their underlying mechanisms

ITER project and fusion technology

International Nuclear Information System (INIS)

Takatsu, H.

2011-01-01

In the sessions of ITR, FTP and SEE of the 23rd IAEA Fusion Energy Conference, 159 papers were presented in total, highlighted by the remarkable progress of the ITER project: ITER baseline has been established and procurement activities have been started as planned with a target of realizing the first plasma in 2019; ITER physics basis is sound and operation scenarios and operational issues have been extensively studied in close collaboration with the worldwide physics community; the test blanket module programme has been incorporated into the ITER programme and extensive R and D works are ongoing in the member countries with a view to delivering their own modules in a timely manner according to the ITER master schedule. Good progress was also reported in the areas of a variety of complementary activities to DEMO, including Broader Approach activities and long-term technology. This paper summarizes the highlights of the papers presented in the ITR, FTP and SEE sessions with a minimum set of background information.

Producing Satisfactory Solutions to Scheduling Problems: An Iterative Constraint Relaxation Approach

Science.gov (United States)

Chien, S.; Gratch, J.

1994-01-01

One drawback to using constraint-propagation in planning and scheduling systems is that when a problem has an unsatisfiable set of constraints such algorithms typically only show that no solution exists. While, technically correct, in practical situations, it is desirable in these cases to produce a satisficing solution that satisfies the most important constraints (typically defined in terms of maximizing a utility function). This paper describes an iterative constraint relaxation approach in which the scheduler uses heuristics to progressively relax problem constraints until the problem becomes satisfiable. We present empirical results of applying these techniques to the problem of scheduling spacecraft communications for JPL/NASA antenna resources.

Iterative regularization in intensity-modulated radiation therapy optimization

International Nuclear Information System (INIS)

Carlsson, Fredrik; Forsgren, Anders

2006-01-01

A common way to solve intensity-modulated radiation therapy (IMRT) optimization problems is to use a beamlet-based approach. The approach is usually employed in a three-step manner: first a beamlet-weight optimization problem is solved, then the fluence profiles are converted into step-and-shoot segments, and finally postoptimization of the segment weights is performed. A drawback of beamlet-based approaches is that beamlet-weight optimization problems are ill-conditioned and have to be regularized in order to produce smooth fluence profiles that are suitable for conversion. The purpose of this paper is twofold: first, to explain the suitability of solving beamlet-based IMRT problems by a BFGS quasi-Newton sequential quadratic programming method with diagonal initial Hessian estimate, and second, to empirically show that beamlet-weight optimization problems should be solved in relatively few iterations when using this optimization method. The explanation of the suitability is based on viewing the optimization method as an iterative regularization method. In iterative regularization, the optimization problem is solved approximately by iterating long enough to obtain a solution close to the optimal one, but terminating before too much noise occurs. Iterative regularization requires an optimization method that initially proceeds in smooth directions and makes rapid initial progress. Solving ten beamlet-based IMRT problems with dose-volume objectives and bounds on the beamlet-weights, we find that the considered optimization method fulfills the requirements for performing iterative regularization. After segment-weight optimization, the treatments obtained using 35 beamlet-weight iterations outperform the treatments obtained using 100 beamlet-weight iterations, both in terms of objective value and of target uniformity. We conclude that iterating too long may in fact deteriorate the quality of the deliverable plan

Void shrinkage in stainless steel during high energy electron irradiation

International Nuclear Information System (INIS)

Singh, B.N.; Foreman, A.J.E.

1976-03-01

During irradiation of thin foils of an austenitic stainless steel in a high voltage electron microscope, steadily growing voids have been observed to suddenly shrink and disappear at the irradiation temperature of 650 0 Cthe phenomenon has been observed in specimens both with and withoutimplanted helium. Possible mechanisms for void shrinkage during irradiation are considered. It is suggested that the dislocation-pipe-diffusion of vacancies from or of self-interstitial atoms to the voids can explain the shrinkage behaviour of voids observed during our experiments. (author)

Strength, shrinkage, erodibility and capillary flow characteristics of cement-treated recycled pavement materials

Directory of Open Access Journals (Sweden)

William Fedrigo

2017-09-01

Full Text Available Full-depth recycling with portland cement (FDR-PC has been widely used for pavement rehabilitation; however, doubts remain regarding factors affecting some properties of the recycled material. Aiming on quantifying the effects of those factors on the strength, drying shrinkage, erodibility, capillary rise and absorption of cement-treated mixtures (CTM of reclaimed asphalt pavement (RAP and graded crushed stone, tests were conducted considering different RAP contents, cement contents, compaction efforts and curing times. Cement addition increased the mixtures strength and reduced their erodibility and capillary flow characteristics, but increased shrinkage. Low cement contents resulted in acceptable strength for CTM, but in high capillary rise and absorption, not being suitable if the layer is exposed to long periods of water soaking. Higher compaction effort led to similar effects as cement addition, counterbalancing low cement contents usage and reducing costs and shrinkage cracking risk. Strength and shrinkage showed higher growth rates at early stages, and then precautions should be taken in order to avoid moisture loss. Increasing RAP content decreased strength; though, RAP effect on the other properties was statistically non-significant, indicating a similar behaviour as CTM without RAP. Considering the studied properties, the mixture with most satisfactory behaviour for field applications was identified. The results highlighted strength is not the only property to be considered when designing FDR-PC mixtures; although presenting acceptable strength, some mixtures may fail due to shrinkage cracking or erosion, when exposed to water content variations. Keywords: Full-depth recycling with cement, Strength, Drying shrinkage, Erodibility, Capillary rise, Absorption

Diversity shrinkage: Cross-validating pareto-optimal weights to enhance diversity via hiring practices.

Science.gov (United States)

Song, Q Chelsea; Wee, Serena; Newman, Daniel A

2017-12-01

To reduce adverse impact potential and improve diversity outcomes from personnel selection, one promising technique is De Corte, Lievens, and Sackett's (2007) Pareto-optimal weighting strategy. De Corte et al.'s strategy has been demonstrated on (a) a composite of cognitive and noncognitive (e.g., personality) tests (De Corte, Lievens, & Sackett, 2008) and (b) a composite of specific cognitive ability subtests (Wee, Newman, & Joseph, 2014). Both studies illustrated how Pareto-weighting (in contrast to unit weighting) could lead to substantial improvement in diversity outcomes (i.e., diversity improvement), sometimes more than doubling the number of job offers for minority applicants. The current work addresses a key limitation of the technique-the possibility of shrinkage, especially diversity shrinkage, in the Pareto-optimal solutions. Using Monte Carlo simulations, sample size and predictor combinations were varied and cross-validated Pareto-optimal solutions were obtained. Although diversity shrinkage was sizable for a composite of cognitive and noncognitive predictors when sample size was at or below 500, diversity shrinkage was typically negligible for a composite of specific cognitive subtest predictors when sample size was at least 100. Diversity shrinkage was larger when the Pareto-optimal solution suggested substantial diversity improvement. When sample size was at least 100, cross-validated Pareto-optimal weights typically outperformed unit weights-suggesting that diversity improvement is often possible, despite diversity shrinkage. Implications for Pareto-optimal weighting, adverse impact, sample size of validation studies, and optimizing the diversity-job performance tradeoff are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Experimental Analysis on Shrinkage and Swelling in Ordinary Concrete

Directory of Open Access Journals (Sweden)

Barbara Kucharczyková

2017-01-01

Full Text Available The paper deals with the experimental determination of shrinkage development during concrete ageing. Three concrete mixtures were made. They differed in the amount of cement in the fresh mixture, 300, 350, and 400 kg/m3. In order to determine the influence of plasticiser on the progress of volume changes, another three concrete mixtures were prepared with plasticiser in the amount of 0.25% by cement mass. Measurements were performed with the goal of observing the influence of cement and plasticiser content on the overall development of volume changes in the concrete. Changes in length and mass losses of the concrete during ageing were measured simultaneously. The continuous measurement of concrete mass losses caused by drying of the specimen’s surface proved useful during the interpretation of results obtained from the concrete shrinkage measurement. During the first 24 hours of ageing, all the concrete mixtures exhibited swelling. Its magnitude and progress were influenced by cement, water, and plasticiser content. However, a loss of mass caused by water evaporation from the surface of the specimens was also recorded in this stage. The measured progress of shrinkage corresponded well to the progress of mass loss.

An Iterative Approach To Development Of A PACS Display Workstation

Science.gov (United States)

O'Malley, Kathleen G.

1989-05-01

An iterative prototyping approach has been used in the development of requirements for a new user interface for the display workstation in the CommView system product line. This approach involves many steps, including development of the preliminary concept, validation and ranking of ideas within that concept, prototyping, evaluating, and revising. We describe in this paper the process undertaken to design and evaluate the new user interface. Staff at Abbott Northwestern Hospital, Bowman Gray/Baptist Hospital Medical Center, Duke University Medical Center, Georgetown University Medical Center and Robert Wood Johnson University Hospital participated in various aspects of the study. The subject population included radiologists, residents, technologists and staff physicians from several areas in the hospitals. Subjects participated in in-depth interviews, answered questionnaires, and performed specific tasks, to aid our development process. We feel this method has resulted in a product that will achieve a high level of customer satisfaction, developed in less time than a traditional approach. Some of the reasons we believe in the value of this approach are: • Users may not be able to describe their needs in terms that designers are expecting, leading to misinterpretation; • Users may not be able to choose between options without seeing them; • Users needs and choices evolve with experience; • Users true choices and needs may not seem logical to one not performing those tasks (i.e., the designers).

Shrinkage and durability study of bridge deck concrete.

Science.gov (United States)

2010-12-01

The Mississippi Department of Transportation is incorporating changes to material : specifications and construction procedures for bridge decks in an effort to reduce shrinkage : cracking. These changes are currently being implemented into a limited ...

Hydration of Portoguese cements, measurement and modelling of chemical shrinkage

DEFF Research Database (Denmark)

Maia, Lino; Geiker, Mette Rica; Figueiras, Joaquim A.

2008-01-01

form of the dispersion model. The development of hydration varied between the investigated cements; based on the measured data the degree of hydration after 24 h hydration at 20 C varied between 40 and 50%. This should be taken into account when comparing properties of concrete made from the different......Development of cement hydration was studied by measuring the chemical shrinkage of pastes. Five types of Portuguese Portland cement were used in cement pastes with . Chemical shrinkage was measured by gravimetry and dilatometry. In gravimeters results were recorded automatically during at least...

The Physics Basis of ITER Confinement

International Nuclear Information System (INIS)

Wagner, F.

2009-01-01

ITER will be the first fusion reactor and the 50 year old dream of fusion scientists will become reality. The quality of magnetic confinement will decide about the success of ITER, directly in the form of the confinement time and indirectly because it decides about the plasma parameters and the fluxes, which cross the separatrix and have to be handled externally by technical means. This lecture portrays some of the basic principles which govern plasma confinement, uses dimensionless scaling to set the limits for the predictions for ITER, an approach which also shows the limitations of the predictions, and describes briefly the major characteristics and physics behind the H-mode--the preferred confinement regime of ITER.

Sudden shrinkage of free rectus abdominis musculocutaneous flap 15 years after maxilla reconstruction

Directory of Open Access Journals (Sweden)

Yasushi Mochizuki

2018-03-01

Full Text Available A 60-year-old male displayed sudden shrinkage of a left free rectus abdominis musculocutaneous flap, which had been grafted to his left maxilla 15 years previously. No post-reconstructive irradiation had been performed, and no late occlusion of the vascular anastomosis, local infection, recurrence of the maxillary cancer, or body weight loss was observed. However, the shrinkage amounted to approximately 50%. This is considerably more than previously reported cases of shrinkage of various free flaps, which ranged between 10% and 25%. The resultant depression was successfully augmented with a right free deep inferior epigastric artery perforator flap. The residual fat volume of the previously grafted shrunken flap was revealed to be compatible with that of the newly harvested contralateral perforator flap. Thus, the volume of the previously grafted flap may reflect the status of the intact contralateral donor site, although the mechanism of sudden flap shrinkage is unclear.

Clay Mineralogy of Brazilian Oxisols with Shrinkage Properties

Directory of Open Access Journals (Sweden)

Samara Alves Testoni

2017-08-01

Full Text Available ABSTRACT Shrinkage capacity (caráter retrátil in Portuguese is a new diagnostic characteristic recently introduced in the Brazilian System of Soil Classification (SiBCS to indicate shrink and swell properties observed in subtropical soils from highland plateaus in southern Brazil, specifically in Oxisols with brown colors. In soils located in road cuts exposed to drying for some weeks, strong shrinkage of soil volume is observed in these soils, resulting in the formation of pronounced vertical cracks and large and very large prismatic structures, which crumble in blocks when handled. We hypothesize that such properties are related to their clay mineralogy, although there are no conclusive studies about this, the motive for the present study. Samples of the A and B horizons from six Oxisols with expansive capacity from the states of Santa Catarina and Rio Grande do Sul were analyzed. One Rhodic Hapludox, from the state of Paraná, without expansive capacity, was used for comparison. All the soils are very clayey, originated from basalt, and have similar iron oxide content. For identification of clay mineralogy, X-ray diffraction techniques were employed, together with the use of NEWMOD® software to investigate and describe the interstratified minerals. The results showed that most expansive soils have a similar mineralogical composition, with kaolinite, interstratified kaolinite-smectite (K-S, and hydroxy-Al interlayered smectites (HIS, unlike the non-expansive Rhodic Hapludox, which exhibited kaolinite with significant amounts of gibbsite and low amount of interstratified K-S. According to the mineralogical assemblage identified in the expansive soils, we can affirm that the mechanism of smectite expansion and contraction is related to the shrinkage capacity of the soil, considering that the level of hydroxy-Al intercalation is low. In addition, these mechanisms also are related to the presence of quasicrystals and domains that control the

ITER EDA Newsletter. V. 2, no. 3

International Nuclear Information System (INIS)

1993-03-01

This ITER EDA (Engineering Design Activities) Newsletter issue includes a description of the ITER Joint Central Team's management, the ITER Management System and supporting software progress, activities of the Special Working Group 2, a brief summary of a technical meeting on the experimental approach to the physics of the high density divertor, a summary on the status of the International Fusion Evaluated Nuclear Data Library (FENDL), and an obituary on Dr. Henry Seligman (IAEA)

Characteristics of low polymerization shrinkage flowable resin composites in newly-developed cavity base materials for bulk filling technique.

Science.gov (United States)

Nitta, Keiko; Nomoto, Rie; Tsubota, Yuji; Tsuchikawa, Masuji; Hayakawa, Tohru

2017-11-29

The purpose of this study was to evaluate polymerization shrinkage and other physical properties of newly-developed cavity base materials for bulk filling technique, with the brand name BULK BASE (BBS). Polymerization shrinkage was measured according to ISO/FDIS 17304. BBS showed the significantly lowest polymerization shrinkage and significantly higher depth of cure than conventional flowable resin composites (p<0.05). The Knoop hardness, flexural strength and elastic modulus of that were significantly lower than conventional flowable resin composites (p<0.05). BBS had the significantly greatest filler content (p<0.05). SEM images of the surface showed failure of fillers. The lowest polymerization shrinkage was due to the incorporation of a new type of low shrinkage monomer, which has urethane moieties. There were no clear correlations between inorganic filler contents and polymerization shrinkage, flexural strength and elastic modulus. In conclusion, the low polymerization shrinkage of BBS will be useful for cavity treatment in dental clinics.

Results of ITER/EDA and Japan's approach in the prolonged research period

International Nuclear Information System (INIS)

Tsunematsu, Toshihide

1998-01-01

The Engineering and Design Activity (EDA) of the International Thermonuclear Experimental Reactor (ITER) started operation with the cooperation of Japan, EU, Russia and the US in July 1992 with a plan to do work on the design of the ITER and necessary R and D. Six years passed and the final report was completed in February 1998, reporting that the initial targets were almost achieved except for design work depending on construction site. It was also decided to prolong the EDA for more three years, though the US did not participate. The new EDA items include: Design to meet site requirements and cost estimation; preparation for application for construction approval; and preparation of technical documents for equipment procurement in the future. Among them, the main EDA item is to design a low-cost ITER to be ready for construction when the three-year joint research is ended. For this, work was done to prepare technical guidelines. The EDA is now making the conceptual design of a new ITER 50% less expensive than the current ITER described in the final design report. Japan has proposed site requirements that are needed for design alteration when the ITER is constructed in Japan. The site requirements are concerned with earthquake resistance, ground, power supply and cooling conditions. (N.H.)

Free-boundary simulations of ITER advanced scenarios

International Nuclear Information System (INIS)

Besseghir, K.

2013-06-01

The successful operation of ITER advanced scenarios is likely to be a major step forward in the development of controlled fusion as a power production source. ITER advanced scenarios raise specific challenges that are not encountered in presently-operated tokamaks. In this thesis, it is argued that ITER advanced operation may benefit from optimal control techniques. Optimal control ensures high performance operation while guaranteeing tokamak integrity. The application of optimal control techniques for ITER operation is assessed and it is concluded that robust optimisation is appropriate for ITER operation of advanced scenarios. Real-time optimisation schemes are discussed and it is concluded that the necessary conditions of optimality tracking approach may potentially be appropriate for ITER operation, thus offering a viable closed-loop optimal control approach. Simulations of ITER advanced operation are necessary in order to assess the present ITER design and uncover the main difficulties that may be encountered during advanced operation. The DINA-CH and CRONOS full tokamak simulator is used to simulate the operation of the ITER hybrid and steady-state scenarios. It is concluded that the present ITER design is appropriate for performing a hybrid scenario pulse lasting more than 1000 sec, with a flat-top plasma current of 12 MA, and a fusion gain of Q ≅ 8. Similarly, a steady-state scenario without internal transport barrier, with a flat-top plasma current of 10 MA, and with a fusion gain of Q ≅ 5 can be realised using the present ITER design. The sensitivity of the advanced scenarios with respect to transport models and physical assumption is assessed using CRONOS. It is concluded that the hybrid scenario and the steady-state scenario are highly sensitive to the L-H transition timing, to the value of the confinement enhancement factor, to the heating and current drive scenario during ramp-up, and, to a lesser extent, to the density peaking and pedestal

Free-boundary simulations of ITER advanced scenarios

Energy Technology Data Exchange (ETDEWEB)

Besseghir, K.

2013-06-15

The successful operation of ITER advanced scenarios is likely to be a major step forward in the development of controlled fusion as a power production source. ITER advanced scenarios raise specific challenges that are not encountered in presently-operated tokamaks. In this thesis, it is argued that ITER advanced operation may benefit from optimal control techniques. Optimal control ensures high performance operation while guaranteeing tokamak integrity. The application of optimal control techniques for ITER operation is assessed and it is concluded that robust optimisation is appropriate for ITER operation of advanced scenarios. Real-time optimisation schemes are discussed and it is concluded that the necessary conditions of optimality tracking approach may potentially be appropriate for ITER operation, thus offering a viable closed-loop optimal control approach. Simulations of ITER advanced operation are necessary in order to assess the present ITER design and uncover the main difficulties that may be encountered during advanced operation. The DINA-CH and CRONOS full tokamak simulator is used to simulate the operation of the ITER hybrid and steady-state scenarios. It is concluded that the present ITER design is appropriate for performing a hybrid scenario pulse lasting more than 1000 sec, with a flat-top plasma current of 12 MA, and a fusion gain of Q ≅ 8. Similarly, a steady-state scenario without internal transport barrier, with a flat-top plasma current of 10 MA, and with a fusion gain of Q ≅ 5 can be realised using the present ITER design. The sensitivity of the advanced scenarios with respect to transport models and physical assumption is assessed using CRONOS. It is concluded that the hybrid scenario and the steady-state scenario are highly sensitive to the L-H transition timing, to the value of the confinement enhancement factor, to the heating and current drive scenario during ramp-up, and, to a lesser extent, to the density peaking and pedestal

A case study of shrinkage-in place leaching of low grade uranium ore deposit

International Nuclear Information System (INIS)

Ding Dexin; Zhou Guohe

1998-09-01

A case study of shrinkage-in place leaching of low grade uranium ore deposit is dealt with. A test block was selected, and the shrinkage mining method was employed to construct the in place heap for leaching. Blast parameters and operations were carefully tried in order to make sure that the fragment size composition was adequate for leaching. A leaching system was planned and the corresponding leaching parameters were tried, too. The results show that the shrinkage method and the parameters for blasting and leaching are all adequate for the in-situ leaching of the blasted ore. This shrinkage-in place leaching system combines the mining and metallurgy processes into one and produces a lot of profits and could be applicable to many low grade uranium ore deposits which are so hard and compact that they have to be fragmented before being leached

Fabrication and characterization of self-folding thermoplastic sheets using unbalanced thermal shrinkage.

Science.gov (United States)

Danielson, Christian; Mehrnezhad, Ali; YekrangSafakar, Ashkan; Park, Kidong

2017-06-14

Self-folding or micro-origami technologies are actively investigated as a novel manufacturing process to fabricate three-dimensional macro/micro-structures. In this paper, we present a simple process to produce a self-folding structure with a biaxially oriented polystyrene sheet (BOPS) or Shrinky Dinks. A BOPS sheet is known to shrink to one-third of its original size in plane, when it is heated above 160 °C. A grid pattern is engraved on one side of the BOPS film with a laser engraver to decrease the thermal shrinkage of the engraved side. The thermal shrinkage of the non-engraved side remains the same and this unbalanced thermal shrinkage causes folding of the structure as the structure shrinks at high temperature. We investigated the self-folding mechanism and characterized how the grid geometry, the grid size, and the power of the laser engraver affect the bending curvature. The developed fabrication process to locally modulate thermomechanical properties of the material by engraving the grid pattern and the demonstrated design methodology to harness the unbalanced thermal shrinkage can be applied to develop complicated self-folding macro/micro structures.

Information operator approach and iterative regularization methods for atmospheric remote sensing

International Nuclear Information System (INIS)

Doicu, A.; Hilgers, S.; Bargen, A. von; Rozanov, A.; Eichmann, K.-U.; Savigny, C. von; Burrows, J.P.

2007-01-01

In this study, we present the main features of the information operator approach for solving linear inverse problems arising in atmospheric remote sensing. This method is superior to the stochastic version of the Tikhonov regularization (or the optimal estimation method) due to its capability to filter out the noise-dominated components of the solution generated by an inappropriate choice of the regularization parameter. We extend this approach to iterative methods for nonlinear ill-posed problems and derive the truncated versions of the Gauss-Newton and Levenberg-Marquardt methods. Although the paper mostly focuses on discussing the mathematical details of the inverse method, retrieval results have been provided, which exemplify the performances of the methods. These results correspond to the NO 2 retrieval from SCIAMACHY limb scatter measurements and have been obtained by using the retrieval processors developed at the German Aerospace Center Oberpfaffenhofen and Institute of Environmental Physics of the University of Bremen

A non-iterative sampling approach using noise subspace projection for EIT

International Nuclear Information System (INIS)

Bellis, Cédric; Constantinescu, Andrei; Coquet, Thomas; Jaravel, Thomas; Lechleiter, Armin

2012-01-01

This study concerns the problem of the reconstruction of inclusions embedded in a conductive medium in the context of electrical impedance tomography (EIT), which is investigated within the framework of a non-iterative sampling approach. This type of identification strategy relies on the construction of a special indicator function that takes, roughly speaking, small values outside the inclusion and large values inside. Such a function is constructed in this paper from the projection of a fundamental singular solution onto the space spanned by the singular vectors associated with some of the smallest singular values of the data-to-measurement operator. The behavior of the novel indicator function is analyzed. For a subsequent implementation in a discrete setting, the quality of classical finite-dimensional approximations of the measurement operator is discussed. The robustness of this approach is also analyzed when only noisy spectral information is available. Finally, this identification method is implemented numerically and experimentally, and its efficiency is discussed on a set of, partly experimental, examples. (paper)

Quantitative analyses of shrinkage characteristics of neem ...

African Journals Online (AJOL)

Quantitative analyses of shrinkage characteristics of neem (Azadirachta indica A. Juss.) wood were carried out. Forty five wood specimens were prepared from the three ecological zones of north eastern Nigeria, viz: sahel savanna, sudan savanna and guinea savanna for the research. The results indicated that the wood ...

Electromagnetic imaging of multiple-scattering small objects: non-iterative analytical approach

International Nuclear Information System (INIS)

Chen, X; Zhong, Y

2008-01-01

Multiple signal classification (MUSIC) imaging method and the least squares method are applied to solve the electromagnetic inverse scattering problem of determining the locations and polarization tensors of a collection of small objects embedded in a known background medium. Based on the analysis of induced electric and magnetic dipoles, the proposed MUSIC method is able to deal with some special scenarios, due to the shapes and materials of objects, to which the standard MUSIC doesn't apply. After the locations of objects are obtained, the nonlinear inverse problem of determining the polarization tensors of objects accounting for multiple scattering between objects is solved by a non-iterative analytical approach based on the least squares method

Efficient approach to simulate EM loads on massive structures in ITER machine

Energy Technology Data Exchange (ETDEWEB)

Alekseev, A. [ITER Organization, Route de Vinon sur Verdon, 13115 St. Paul-Lez-Durance (France); Andreeva, Z.; Belov, A.; Belyakov, V.; Filatov, O. [D.V. Efremov Scientific Research Institute, 196641 St. Petersburg (Russian Federation); Gribov, Yu.; Ioki, K. [ITER Organization, Route de Vinon sur Verdon, 13115 St. Paul-Lez-Durance (France); Kukhtin, V.; Labusov, A.; Lamzin, E.; Lyublin, B.; Malkov, A.; Mazul, I. [D.V. Efremov Scientific Research Institute, 196641 St. Petersburg (Russian Federation); Rozov, V.; Sugihara, M. [ITER Organization, Route de Vinon sur Verdon, 13115 St. Paul-Lez-Durance (France); Sychevsky, S., E-mail: sytch@sintez.niiefa.spb.su [D.V. Efremov Scientific Research Institute, 196641 St. Petersburg (Russian Federation)

2013-10-15

Highlights: ► A modelling technique to predict EM loads in ITER conducting structures is presented. ► The technique provides low computational cost and parallel computations. ► Detailed models were built for the system “vacuum vessel, cryostat, thermal shields”. ► EM loads on massive in-vessel structures were simulated with the use of local models. ► A flexible combination of models enables desired accuracy of load distributions. -- Abstract: Operation of the ITER machine is associated with high electromagnetic (EM) loads. An essential contributor to EM loads is eddy currents induced in passive conductive structures. Reasoning from the ITER construction, a modelling technique has been developed and applied in computations to efficiently predict anticipated loads. The technique allows us to avoid building a global 3D finite-element (FE) model that requires meshing of the conducting structures and their vacuum environment into 3D solid elements that leads to high computational cost. The key features of the proposed technique are: (i) the use of an existing shell model for the system “vacuum vessel (VV), cryostat, and thermal shields (TS)” implementing the magnetic shell approach. A solution is obtained in terms of a single-component, in this case, vector electric potential taken within the conducting shells of the “VV + cryostat + TS” system. (ii) EM loads on in-vessel conducting structures are simulated with the use of local FE models. The local models use either the 3D solid body or shell approximations. Reasoning from the simulation efficiency, the local boundary conditions are put with respect to the total field or an external field. The use of an integral-differential formulation and special procedures ensures smooth and accurate simulated distributions of fields from current sources of any geometry. The local FE models have been developed and applied for EM analyses of a variety of the ITER components including the diagnostic systems

Study of Drying Shrinkage Cracking by Lattice Gas Automaton and Environmental Scanning Electron Microscope

NARCIS (Netherlands)

Van Mier, J.G.M.; Jankovic, D.

2005-01-01

Numerical modeling of moisture flow, drying shrinkage and crack phenomena in cement microstructure, by coupling a Lattice Gas Automaton and a Lattice Fracture Model, highlighted the importance of a shrinkage coefficient (?sh) as the most significant parameter for achieving realistic numerical

Effects of Shrinkage Reducing Agent and Expansive Additive on Mortar Properties

Directory of Open Access Journals (Sweden)

Sarapon Treesuwan

2017-01-01

Full Text Available This research is to study the effect of mortar mixed with shrinkage reducing agent (polyoxyalkylene alkyl ether type, expansive additive (CaO type, and fly ash (hereinafter “SRA,” “EX,” and “FA,” resp.. Moreover, steam curing was studied to improve the properties of mortar. The plastic shrinkage test was conducted by using the strain gauge embedded at 0.5 cm from the surface according to the ASTM C1579-06 standard within early age followed by the total shrinkage test and compressive strength test. The test results showed that mixing both the EX and SRA increases the plastic enlargement of the mortar during the early age more than using either the EX or SRA solely. The steam curing helps to reduce the plastic shrinkage when the mortar is added with the FA and SRA while adding the EX increases the enlargement compared to the normal curing. When the EX, SRA, and FA are all added to the mortar mixing, great attention should be paid due to the increase of greater enlargement. For the compressive strength view, the steam curing increases the compressive strength in all types of mixture. The steam curing significantly helps increasing the compressive strength of mortar with combination of EX, SRA, and FA. Nevertheless, the XRD and SEM tests explain such enlargement accordingly.

RAMI analysis of the ITER Central Safety System

Energy Technology Data Exchange (ETDEWEB)

Kitazawa, Sin-iti, E-mail: kitazawa.siniti@jaea.go.jp [ITER Project Unit, Japan Atomic Energy Agency (JAEA), Naka, 311-0193 Ibaraki (Japan); Okayama, Katsumi [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Neyatani, Yuzuru [ITER Project Unit, Japan Atomic Energy Agency (JAEA), Naka, 311-0193 Ibaraki (Japan); Sagot, Francois; Houtte, Didier van [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

2014-06-15

Highlights: • We performed the functional analysis of the ITER CSS. • We performed a failure mode analysis of the ITER CSS. • We estimated the reliability and availability of the ITER CSS. • The ITER RAMI approach was applied to the ITER CSS for technical risk control in the design phase. - Abstract: ITER is the first worldwide international project aiming to design a facility to produce nuclear fusion energy. The technical requirements of its plant systems have been established in the ITER Project Baseline. In the project, the Reliability, Availability, Maintainability and Inspectability (RAMI) approach has been adopted for technical risk control to help aid the design of the components in preparation for operation and maintenance. A RAMI analysis was performed on the conceptual design of the ITER Central Safety System (CSS). A functional breakdown was prepared in a bottom-up approach, resulting in the system being divided into 2 main functions and 20 sub-functions. These functions were described using the IDEF0 method. Reliability block diagrams were prepared to estimate the reliability and availability of each function under the stipulated operating conditions. Initial and expected scenarios were analyzed to define risk-mitigation actions. The inherent availability of the ITER CSS expected after implementation of mitigation actions was calculated to be 99.80% over 2 years, which is the typical interval of the scheduled maintenance cycles. This is consistent with the project required value of 99.9 ± 0.1%. A Failure Modes, Effects and Criticality Analysis was performed with criticality charts highlighting the risk level of the different failure modes with regard to their probability of occurrence and their effects on the availability of the plasma operation. This analysis defined when risk mitigation actions were required in terms of design, testing, operation procedures and/or maintenance to reduce the risk levels and increase the availability of the

Autogenous and drying shrinkage of sodium carbonate activated slag altered by limestone powder incorporation

NARCIS (Netherlands)

Yuan, B.; Yu, Q.L.; Dainese, E.; Brouwers, H.J.H.

2017-01-01

This paper aims to study the shrinkage mechanism of sodium carbonate activated slag containing limestone powder (LP). The workability, pore structure, reaction kinetics and strength development were characterized. The results show that the autogenous shrinkage increases when the dosage of LP is low

Application of Artificial Neural Network to Predict Colour Change, Shrinkage and Texture of Osmotically Dehydrated Pumpkin

Science.gov (United States)

Tang, S. Y.; Lee, J. S.; Loh, S. P.; Tham, H. J.

2017-06-01

The objectives of this study were to use Artificial Neural Network (ANN) to predict colour change, shrinkage and texture of osmotically dehydrated pumpkin slices. The effects of process variables such as concentration of osmotic solution, immersion temperature and immersion time on the above mentioned physical properties were studied. The colour of the samples was measured using a colorimeter and the net colour difference changes, ΔE were determined. The texture was measured in terms of hardness by using a Texture Analyzer. As for the shrinkage, displacement of volume method was applied and percentage of shrinkage was obtained in terms of volume changes. A feed-forward backpropagation network with sigmoidal function was developed and best network configuration was chosen based on the highest correlation coefficients between the experimental values versus predicted values. As a comparison, Response Surface Methodology (RSM) statistical analysis was also employed. The performances of both RSM and ANN modelling were evaluated based on absolute average deviation (AAD), correlation of determination (R2) and root mean square error (RMSE). The results showed that ANN has higher prediction capability as compared to RSM. The relative importance of the variables on the physical properties were also determined by using connection weight approach in ANN. It was found that solution concentration showed the highest influence on all three physical properties.

MULTI-LEVEL SAMPLING APPROACH FOR CONTINOUS LOSS DETECTION USING ITERATIVE WINDOW AND STATISTICAL MODEL

OpenAIRE

Mohd Fo'ad Rohani; Mohd Aizaini Maarof; Ali Selamat; Houssain Kettani

2010-01-01

This paper proposes a Multi-Level Sampling (MLS) approach for continuous Loss of Self-Similarity (LoSS) detection using iterative window. The method defines LoSS based on Second Order Self-Similarity (SOSS) statistical model. The Optimization Method (OM) is used to estimate self-similarity parameter since it is fast and more accurate in comparison with other estimation methods known in the literature. Probability of LoSS detection is introduced to measure continuous LoSS detection performance...

Modeling of Flexible Polyurethane Foam Shrinkage for Bra Cup Moulding Process Control

Directory of Open Access Journals (Sweden)

Long Wu

2018-04-01

Full Text Available Nowadays, moulding technology has become a remarkable manufacturing process in the intimate apparel industry. Polyurethane (PU foam sheets are used to mould three-dimensional (3D seamless bra cups of various softness and shapes, which eliminate bulky seams and reduce production costs. However, it has been challenging to accurately and effectively control the moulding process and bra cup thickness. In this study, the theoretical mechanism of heat transfer and the thermal conductivity of PU foams are first examined. Experimental studies are carried out to investigate the changes in foam materials at various moulding conditions (viz., temperatures, and lengths of dwell time in terms of surface morphology and thickness by using electron and optical microscopy. Based on the theoretical and experimental investigations of the thermal conductivity of the foam materials, empirical equations of shrinkage ratio and thermal conduction of foam materials were established. A regression model to predict flexible PU foam shrinkage during the bra cup moulding process was formulated by using the Levenberg-Marquardt method of nonlinear least squares algorithm and verified for accuracy. This study therefore provides an effective approach that optimizes control of the bra cup moulding process and assures the ultimate quality and thickness of moulded foam cups.

Modified creep and shrinkage prediction model B3 for serviceability limit state analysis of composite slabs

Science.gov (United States)

Gholamhoseini, Alireza

2016-03-01

Relatively little research has been reported on the time-dependent in-service behavior of composite concrete slabs with profiled steel decking as permanent formwork and little guidance is available for calculating long-term deflections. The drying shrinkage profile through the thickness of a composite slab is greatly affected by the impermeable steel deck at the slab soffit, and this has only recently been quantified. This paper presents the results of long-term laboratory tests on composite slabs subjected to both drying shrinkage and sustained loads. Based on laboratory measurements, a design model for the shrinkage strain profile through the thickness of a slab is proposed. The design model is based on some modifications to an existing creep and shrinkage prediction model B3. In addition, an analytical model is developed to calculate the time-dependent deflection of composite slabs taking into account the time-dependent effects of creep and shrinkage. The calculated deflections are shown to be in good agreement with the experimental measurements.

Polymerization stresses in low-shrinkage dental resin composites measured by crack analysis.

Science.gov (United States)

Yamamoto, Takatsugu; Kubota, Yu; Momoi, Yasuko; Ferracane, Jack L

2012-09-01

The objective of this study was to compare several dental restoratives currently advertised as low-shrinkage composites (Clearfil Majesty Posterior, Kalore, Reflexions XLS Dentin and Venus Diamond) with a microfill composite (Heliomolar) in terms of polymerization stress, polymerization shrinkage and elastic modulus. Cracks were made at several distances from the edge of a precision cavity in a soda-lime glass disk. The composites were placed into the cavity and lengths of the cracks were measured before and after light curing. Polymerization stresses generated in the glass at 2 and 10 min after the irradiation were calculated from the crack lengths and K(c) of the glass. Polymerization shrinkage and elastic modulus of the composites also were measured at 2 and 10 min after irradiation using a video-imaging device and a nanoindenter, respectively. The data were statistically analyzed by ANOVAs and Tukey's test (pelastic moduli of Clearfil Majesty Posterior and Reflexions XLS Dentin were greatest at 2 and 10 min, respectively. Among the four low-shrinkage composites, two demonstrated significantly reduced polymerization stress compared to Heliomolar, which has previously been shown in in vitro tests to generate low curing stress. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Mathematical model for creep and thermal shrinkage of concrete at high temperature

International Nuclear Information System (INIS)

Bazant, Z.P.

1983-01-01

Based on the existing limited test data, it is possible to set up an approximate constitutive model for creep and shrinkage at temperatures above 100 0 C, up to about 400 0 C. The model presented here describes the effect of various constant temperatures on the creep rate and the rate of aging, similar effects of the specific water content, the creep increase caused by simultaneous changes in moisture content, the thermal volume changes as well as the volume changes caused by changes in moisture content (drying shrinkage or thermal shrinkage), and the effect of pore pressure produced by heating. Generalizations to time-variable stresses and multiaxial stresses are also given. The model should allow more realistic analysis of reactor vessels and containments for accident situations, of concrete structures subjected to fire, of vessels for coal gasification or liquefaction, etc. (orig.)

Four-Phase Dendritic Model for the Prediction of Macrosegregation, Shrinkage Cavity, and Porosity in a 55-Ton Ingot

Science.gov (United States)

Ge, Honghao; Ren, Fengli; Li, Jun; Han, Xiujun; Xia, Mingxu; Li, Jianguo

2017-03-01

A four-phase dendritic model was developed to predict the macrosegregation, shrinkage cavity, and porosity during solidification. In this four-phase dendritic model, some important factors, including dendritic structure for equiaxed crystals, melt convection, crystals sedimentation, nucleation, growth, and shrinkage of solidified phases, were taken into consideration. Furthermore, in this four-phase dendritic model, a modified shrinkage criterion was established to predict shrinkage porosity (microporosity) of a 55-ton industrial Fe-3.3 wt pct C ingot. The predicted macrosegregation pattern and shrinkage cavity shape are in a good agreement with experimental results. The shrinkage cavity has a significant effect on the formation of positive segregation in hot top region, which generally forms during the last stage of ingot casting. The dendritic equiaxed grains also play an important role on the formation of A-segregation. A three-dimensional laminar structure of A-segregation in industrial ingot was, for the first time, predicted by using a 3D case simulation.

The potential of computer vision, optical backscattering parameters and artificial neural network modelling in monitoring the shrinkage of sweet potato (Ipomoea batatas L.) during drying.

Science.gov (United States)

Onwude, Daniel I; Hashim, Norhashila; Abdan, Khalina; Janius, Rimfiel; Chen, Guangnan

2018-03-01

Drying is a method used to preserve agricultural crops. During the drying of products with high moisture content, structural changes in shape, volume, area, density and porosity occur. These changes could affect the final quality of dried product and also the effective design of drying equipment. Therefore, this study investigated a novel approach in monitoring and predicting the shrinkage of sweet potato during drying. Drying experiments were conducted at temperatures of 50-70 °C and samples thicknesses of 2-6 mm. The volume and surface area obtained from camera vision, and the perimeter and illuminated area from backscattered optical images were analysed and used to evaluate the shrinkage of sweet potato during drying. The relationship between dimensionless moisture content and shrinkage of sweet potato in terms of volume, surface area, perimeter and illuminated area was found to be linearly correlated. The results also demonstrated that the shrinkage of sweet potato based on computer vision and backscattered optical parameters is affected by the product thickness, drying temperature and drying time. A multilayer perceptron (MLP) artificial neural network with input layer containing three cells, two hidden layers (18 neurons), and five cells for output layer, was used to develop a model that can monitor, control and predict the shrinkage parameters and moisture content of sweet potato slices under different drying conditions. The developed ANN model satisfactorily predicted the shrinkage and dimensionless moisture content of sweet potato with correlation coefficient greater than 0.95. Combined computer vision, laser light backscattering imaging and artificial neural network can be used as a non-destructive, rapid and easily adaptable technique for in-line monitoring, predicting and controlling the shrinkage and moisture changes of food and agricultural crops during drying. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Effects of Prepolymerized Particle Size and Polymerization Kinetics on Volumetric Shrinkage of Dental Modeling Resins

Directory of Open Access Journals (Sweden)

Tae-Yub Kwon

2014-01-01

Full Text Available Dental modeling resins have been developed for use in areas where highly precise resin structures are needed. The manufacturers claim that these polymethyl methacrylate/methyl methacrylate (PMMA/MMA resins show little or no shrinkage after polymerization. This study examined the polymerization shrinkage of five dental modeling resins as well as one temporary PMMA/MMA resin (control. The morphology and the particle size of the prepolymerized PMMA powders were investigated by scanning electron microscopy and laser diffraction particle size analysis, respectively. Linear polymerization shrinkage strains of the resins were monitored for 20 minutes using a custom-made linometer, and the final values (at 20 minutes were converted into volumetric shrinkages. The final volumetric shrinkage values for the modeling resins were statistically similar (P>0.05 or significantly larger (P<0.05 than that of the control resin and were related to the polymerization kinetics (P<0.05 rather than the PMMA bead size (P=0.335. Therefore, the optimal control of the polymerization kinetics seems to be more important for producing high-precision resin structures rather than the use of dental modeling resins.

Durability and Shrinkage Characteristics of Self-Compacting Concretes Containing Recycled Coarse and/or Fine Aggregates

Directory of Open Access Journals (Sweden)

Mehmet Gesoglu

2015-01-01

Full Text Available This paper addresses durability and shrinkage performance of the self-compacting concretes (SCCs in which natural coarse aggregate (NCA and/or natural fine aggregate (NFA were replaced by recycled coarse aggregate (RCA and/or recycled fine aggregate (RFA, respectively. A total of 16 SCCs were produced and classified into four series, each of which included four mixes designed with two water to binder (w/b ratios of 0.3 and 0.43 and two silica fume replacement levels of 0 and 10%. Durability properties of SCCs were tested for rapid chloride penetration, water sorptivity, gas permeability, and water permeability at 56 days. Also, drying shrinkage accompanied by the water loss and restrained shrinkage of SCCs were monitored over 56 days of drying period. Test results revealed that incorporating recycled coarse and/or fine aggregates aggravated the durability properties of SCCs tested in this study. The drying shrinkage and restrained shrinkage cracking of recycled aggregate (RA concretes had significantly poorer performance than natural aggregate (NA concretes. The time of cracking greatly prolonged as the RAs were used along with the increase in water/binder ratio.

Combined Use of Shrinkage Reducing Admixture and CaO in Cement Based Materials

Science.gov (United States)

Tittarelli, Francesca; Giosuè, Chiara; Monosi, Saveria

2017-10-01

The combined addition of a Shrinkage-Reducing Admixture (SRA) with a CaO-based expansive agent (CaO) has been found to have a synergistic effect to improve the dimensional stability of cement based materials. In this work, aimed to further investigate the effect, mortar and self-compacting concrete specimens were prepared either without admixtures, as reference, or with SRA alone and/or CaO. Their performance was compared in terms of compressive strength and free shrinkage measurements. Results showed that the synergistic effect in reducing shrinkage is confirmed in the specimens manufactured with SRA and CaO. In order to clarify this phenomenon, the effect of SRA on the hydration of CaO as well as cement was evaluated through different techniques. The obtained results show that SRA induces a finer microstructure of the CaO hydration products and a retarding effect on the microstructure development of cement based materials. A more deformable mortar or concrete, due to the delay in microstructure development by SRA, coupled with a finer microstructure of CaO hydration products could allow higher early expansion, which might contribute in contrasting better the successive drying shrinkage.

Experimental evaluation and simulation of volumetric shrinkage and warpage on polymeric composite reinforced with short natural fibers

Science.gov (United States)

Santos, Jonnathan D.; Fajardo, Jorge I.; Cuji, Alvaro R.; García, Jaime A.; Garzón, Luis E.; López, Luis M.

2015-09-01

A polymeric natural fiber-reinforced composite is developed by extrusion and injection molding process. The shrinkage and warpage of high-density polyethylene reinforced with short natural fibers of Guadua angustifolia Kunth are analyzed by experimental measurements and computer simulations. Autodesk Moldflow® and Solid Works® are employed to simulate both volumetric shrinkage and warpage of injected parts at different configurations: 0 wt.%, 20 wt.%, 30 wt.% and 40 wt.% reinforcing on shrinkage and warpage behavior of polymer composite. Become evident the restrictive effect of reinforcing on the volumetric shrinkage and warpage of injected parts. The results indicate that volumetric shrinkage of natural composite is reduced up to 58% with fiber increasing, whereas the warpage shows a reduction form 79% to 86% with major fiber content. These results suggest that it is a highly beneficial use of natural fibers to improve the assembly properties of polymeric natural fiber-reinforced composites.

Reoxygenation of hypoxic cells by tumor shrinkage during irradiation. A computer simulation

International Nuclear Information System (INIS)

Kocher, M.; Treuer, H.

1995-01-01

A 3-dimensional computer simulation was developed in order to estimate the impact of tumor shrinkage on reoxygenation of chronic hypoxic tumor cells during a full course of fractionated irradiation. The growth of a small tumor situated in a vascularized stroma with 350 capillary cross-sections/mm 3 which were displaced by the growing tumor was simulated. Tumors contained 10 4 cells when irradiation started, intrinsic radiosensitivity was set to either low (α=0.3 Gy -1 , β=0.03 Gy -2 ) or high (α=0.4 Gy -1 , β=0.04 Gy -2 ) values. Oxygen enhancement ratio was 3.0, potential tumor doubling time T pot =1, 2 or 5 days. A simulated fractionated radiotherapy was carried out with daily fractions of 2.0 Gy, total dose 50 to 70 Gy. The presence or absence of factors preventing tumor cord shrinkage was also included. During the growth phase, all tumors developed a necrotic core with a hypoxic cell fraction of 25% under these conditions. During irradiation, the slower growing tumors (T pot =2 to 5 days) showed complete reoxygenation of the hypoxic cells after 30 to 40 Gy independent from radiosensitivity, undisturbed tumor shrinkage provided. If shrinkage was prevented, the hypoxic fraction rose to 100% after 30 to 50 Gy. Local tumor control, defined as the destruction of all clonogenic and hypoxic tumor cells increased by 20 to 100% due to reoxygenation and 50 Gy were enough in order to sterilize the tumors in these cases. In the fast growing tumors (T pot =1 day), reoxygenation was only observed in the case of high radiosensitivity and undisturbed tumor shrinkage. In these tumors reoxygenation increased the control rates by up to 60%. (orig./MG) [de

An iterative particle filter approach for coupled hydro-geophysical inversion of a controlled infiltration experiment

International Nuclear Information System (INIS)

Manoli, Gabriele; Rossi, Matteo; Pasetto, Damiano; Deiana, Rita; Ferraris, Stefano; Cassiani, Giorgio; Putti, Mario

2015-01-01

The modeling of unsaturated groundwater flow is affected by a high degree of uncertainty related to both measurement and model errors. Geophysical methods such as Electrical Resistivity Tomography (ERT) can provide useful indirect information on the hydrological processes occurring in the vadose zone. In this paper, we propose and test an iterated particle filter method to solve the coupled hydrogeophysical inverse problem. We focus on an infiltration test monitored by time-lapse ERT and modeled using Richards equation. The goal is to identify hydrological model parameters from ERT electrical potential measurements. Traditional uncoupled inversion relies on the solution of two sequential inverse problems, the first one applied to the ERT measurements, the second one to Richards equation. This approach does not ensure an accurate quantitative description of the physical state, typically violating mass balance. To avoid one of these two inversions and incorporate in the process more physical simulation constraints, we cast the problem within the framework of a SIR (Sequential Importance Resampling) data assimilation approach that uses a Richards equation solver to model the hydrological dynamics and a forward ERT simulator combined with Archie's law to serve as measurement model. ERT observations are then used to update the state of the system as well as to estimate the model parameters and their posterior distribution. The limitations of the traditional sequential Bayesian approach are investigated and an innovative iterative approach is proposed to estimate the model parameters with high accuracy. The numerical properties of the developed algorithm are verified on both homogeneous and heterogeneous synthetic test cases based on a real-world field experiment

An iterative particle filter approach for coupled hydro-geophysical inversion of a controlled infiltration experiment

Energy Technology Data Exchange (ETDEWEB)

Manoli, Gabriele, E-mail: manoli@dmsa.unipd.it [Department of Mathematics, University of Padova, Via Trieste 63, 35121 Padova (Italy); Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States); Rossi, Matteo [Department of Geosciences, University of Padova, Via Gradenigo 6, 35131 Padova (Italy); Pasetto, Damiano [Department of Mathematics, University of Padova, Via Trieste 63, 35121 Padova (Italy); Deiana, Rita [Dipartimento dei Beni Culturali, University of Padova, Piazza Capitaniato 7, 35139 Padova (Italy); Ferraris, Stefano [Interuniversity Department of Regional and Urban Studies and Planning, Politecnico and University of Torino, Viale Mattioli 39, 10125 Torino (Italy); Cassiani, Giorgio [Department of Geosciences, University of Padova, Via Gradenigo 6, 35131 Padova (Italy); Putti, Mario [Department of Mathematics, University of Padova, Via Trieste 63, 35121 Padova (Italy)

2015-02-15

The modeling of unsaturated groundwater flow is affected by a high degree of uncertainty related to both measurement and model errors. Geophysical methods such as Electrical Resistivity Tomography (ERT) can provide useful indirect information on the hydrological processes occurring in the vadose zone. In this paper, we propose and test an iterated particle filter method to solve the coupled hydrogeophysical inverse problem. We focus on an infiltration test monitored by time-lapse ERT and modeled using Richards equation. The goal is to identify hydrological model parameters from ERT electrical potential measurements. Traditional uncoupled inversion relies on the solution of two sequential inverse problems, the first one applied to the ERT measurements, the second one to Richards equation. This approach does not ensure an accurate quantitative description of the physical state, typically violating mass balance. To avoid one of these two inversions and incorporate in the process more physical simulation constraints, we cast the problem within the framework of a SIR (Sequential Importance Resampling) data assimilation approach that uses a Richards equation solver to model the hydrological dynamics and a forward ERT simulator combined with Archie's law to serve as measurement model. ERT observations are then used to update the state of the system as well as to estimate the model parameters and their posterior distribution. The limitations of the traditional sequential Bayesian approach are investigated and an innovative iterative approach is proposed to estimate the model parameters with high accuracy. The numerical properties of the developed algorithm are verified on both homogeneous and heterogeneous synthetic test cases based on a real-world field experiment.

GENERALIZED DOUBLE PARETO SHRINKAGE.

Science.gov (United States)

Armagan, Artin; Dunson, David B; Lee, Jaeyong

2013-01-01

We propose a generalized double Pareto prior for Bayesian shrinkage estimation and inferences in linear models. The prior can be obtained via a scale mixture of Laplace or normal distributions, forming a bridge between the Laplace and Normal-Jeffreys' priors. While it has a spike at zero like the Laplace density, it also has a Student's t -like tail behavior. Bayesian computation is straightforward via a simple Gibbs sampling algorithm. We investigate the properties of the maximum a posteriori estimator, as sparse estimation plays an important role in many problems, reveal connections with some well-established regularization procedures, and show some asymptotic results. The performance of the prior is tested through simulations and an application.

Reduction of cracking and shrinkage in compressed clay beams during dying

International Nuclear Information System (INIS)

Lakho, N.A.; Zardari, M.A.; Memon, N.A.

2016-01-01

Uncontrolled evaporation of moisture from compressed clay beams can cause surface cracks, resulting in reduction of strength. This paper presents various treatments applied to clay beams during the process of casting, compacting and drying in order to curtail the possibility of cracking and to decrease percentage of drying shrinkage. Following treatments were applied to the beams during casting and drying: (i) a steel plate and double layer of plastic sheet was provided between the beam and the plank, (ii) the beam was enveloped with a propylene fabric sheet during casting and (iii) beams were covered with plastic sheet during drying. Using these treatments, the clay beams were cast and compacted at various intensities of compaction. The results show that the drying shrinkage was reduced to minimum and the cracks were curtailed. The rate of drying shrinkage was decreased depending upon the level of compaction. Thus at the higher degree of compaction, more density of clay beams was achieved, which resulted in higher degree of compressive strength in baked and unbaked state. (author)

Development of high shrinkage polyethylene terephthalate (PET) shape memory polymer tendons for concrete crack closure

Science.gov (United States)

Teall, Oliver; Pilegis, Martins; Sweeney, John; Gough, Tim; Thompson, Glen; Jefferson, Anthony; Lark, Robert; Gardner, Diane

2017-04-01

The shrinkage force exerted by restrained shape memory polymers (SMPs) can potentially be used to close cracks in structural concrete. This paper describes the physical processing and experimental work undertaken to develop high shrinkage die-drawn polyethylene terephthalate (PET) SMP tendons for use within a crack closure system. The extrusion and die-drawing procedure used to manufacture a series of PET tendon samples is described. The results from a set of restrained shrinkage tests, undertaken at differing activation temperatures, are also presented along with the mechanical properties of the most promising samples. The stress developed within the tendons is found to be related to the activation temperature, the cross-sectional area and to the draw rate used during manufacture. Comparisons with commercially-available PET strip samples used in previous research are made, demonstrating an increase in restrained shrinkage stress by a factor of two for manufactured PET filament samples.

Numerical Simulation on Open Wellbore Shrinkage and Casing Equivalent Stress in Bedded Salt Rock Stratum

Directory of Open Access Journals (Sweden)

Jianjun Liu

2013-01-01

Full Text Available Most salt rock has interbed of mudstone in China. Owing to the enormous difference of mechanical properties between the mudstone interbed and salt rock, the stress-strain and creep behaviors of salt rock are significantly influenced by neighboring mudstone interbed. In order to identify the rules of wellbore shrinkage and casings equivalent stress in bedded salt rock stratum, three-dimensional finite difference models were established. The effects of thickness and elasticity modulus of mudstone interbed on the open wellbore shrinkage and equivalent stress of casing after cementing operation were studied, respectively. The results indicate that the shrinkage of open wellbore and equivalent stress of casings decreases with the increase of mudstone interbed thickness. The increasing of elasticity modulus will reduce the shrinkage of open wellbore and casing equivalent stress. Research results can provide the scientific basis for the design of mud density and casing strength.

A thermal active restrained shrinkage ring test to study the early age concrete behaviour of massive structures

International Nuclear Information System (INIS)

Briffaut, M.; Benboudjema, F.; Torrenti, J.M.; Nahas, G.

2011-01-01

In massive concrete structures, cracking may occur during hardening, especially if autogenous and thermal strains are restrained. The concrete permeability due to this cracking may rise significantly and thus increase leakage (in tank, nuclear containment...) and reduce the durability. The restrained shrinkage ring test is used to study the early age concrete behaviour (delayed strains evolution and cracking). This test shows, at 20 o C and without drying, for a concrete mix which is representative of a French nuclear power plant containment vessel (w/c ratio equal to 0.57), that the amplitude of autogenous shrinkage (about 40 μm/m for the studied concrete mix) is not high enough to cause cracking. Indeed, in this configuration, thermal shrinkage is not significant, whereas this is a major concern for massive structures. Therefore, an active test has been developed to study cracking due to restrained thermal shrinkage. This test is an evolution of the classical restrained shrinkage ring test. It allows to take into account both autogenous and thermal shrinkages. Its principle is to create the thermal strain effects by increasing the temperature of the brass ring (by a fluid circulation) in order to expand it. With this test, the early age cracking due to restrained shrinkage, the influence of reinforcement and construction joints have been experimentally studied. It shows that, as expected, reinforcement leads to an increase of the number of cracks but a decrease of crack widths. Moreover, cracking occurs preferentially at the construction joint.

Iterative-Transform Phase Retrieval Using Adaptive Diversity

Science.gov (United States)

Dean, Bruce H.

2007-01-01

A phase-diverse iterative-transform phase-retrieval algorithm enables high spatial-frequency, high-dynamic-range, image-based wavefront sensing. [The terms phase-diverse, phase retrieval, image-based, and wavefront sensing are defined in the first of the two immediately preceding articles, Broadband Phase Retrieval for Image-Based Wavefront Sensing (GSC-14899-1).] As described below, no prior phase-retrieval algorithm has offered both high dynamic range and the capability to recover high spatial-frequency components. Each of the previously developed image-based phase-retrieval techniques can be classified into one of two categories: iterative transform or parametric. Among the modifications of the original iterative-transform approach has been the introduction of a defocus diversity function (also defined in the cited companion article). Modifications of the original parametric approach have included minimizing alternative objective functions as well as implementing a variety of nonlinear optimization methods. The iterative-transform approach offers the advantage of ability to recover low, middle, and high spatial frequencies, but has disadvantage of having a limited dynamic range to one wavelength or less. In contrast, parametric phase retrieval offers the advantage of high dynamic range, but is poorly suited for recovering higher spatial frequency aberrations. The present phase-diverse iterative transform phase-retrieval algorithm offers both the high-spatial-frequency capability of the iterative-transform approach and the high dynamic range of parametric phase-recovery techniques. In implementation, this is a focus-diverse iterative-transform phaseretrieval algorithm that incorporates an adaptive diversity function, which makes it possible to avoid phase unwrapping while preserving high-spatial-frequency recovery. The algorithm includes an inner and an outer loop (see figure). An initial estimate of phase is used to start the algorithm on the inner loop, wherein

RAMI analysis for ITER radial X-ray camera system

Energy Technology Data Exchange (ETDEWEB)

Qin, Shijun, E-mail: sjqin@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Hu, Liqun; Chen, Kaiyun [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Barnsley, Robin; Sirinelli, Antoine [ITER Organization, Route Vinon sur Verdon, CS 90046, 13067, St. Paul lez Durance, Cedex (France); Song, Yuntao; Lu, Kun; Yao, Damao; Chen, Yebin; Li, Shi; Cao, Hongrui; Yu, Hong; Sheng, Xiuli [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2016-11-15

Highlights: • The functional analysis of the ITER RXC system was performed. • A failure modes, effects and criticality analysis of the ITER RXC system was performed. • The reliability and availability of the ITER RXC system and its main functions were calculated. • The ITER RAMI approach was applied to the ITER RXC system for technical risk control in the preliminary design phase. - Abstract: ITER is the first international experimental nuclear fusion device. In the project, the RAMI approach (reliability, availability, maintainability and inspectability) has been adopted for technical risk control to mitigate all the possible failure of components in preparation for operation and maintenance. RAMI analysis of the ITER Radial X-ray Camera diagnostic (RXC) system during preliminary design phase was required, which insures the system with a very high performance to measure the X-ray emission and research the MHD of plasma with high accuracy on the ITER machine. A functional breakdown was prepared in a bottom-up approach, resulting in the system being divided into 3 main functions, 6 intermediate functions and 28 basic functions which are described using the IDEFØ method. Reliability block diagrams (RBDs) were prepared to calculate the reliability and availability of each function under assumption of operating conditions and failure data. Initial and expected scenarios were analyzed to define risk-mitigation actions. The initial availability of RXC system was 92.93%, while after optimization the expected availability was 95.23% over 11,520 h (approx. 16 months) which corresponds to ITER typical operation cycle. A Failure Modes, Effects and Criticality Analysis (FMECA) was performed to the system initial risk. Criticality charts highlight the risks of the different failure modes with regard to the probability of their occurrence and impact on operations. There are 28 risks for the initial state, including 8 major risks. No major risk remains after taking into

Analysis of Shrinkage on Thick Plate Part using Genetic Algorithm

Directory of Open Access Journals (Sweden)

Najihah S.N.

2016-01-01

Full Text Available Injection moulding is the most widely used processes in manufacturing plastic products. Since the quality of injection improves plastic parts are mostly influenced by process conditions, the method to determine the optimum process conditions becomes the key to improving the part quality. This paper presents a systematic methodology to analyse the shrinkage of the thick plate part during the injection moulding process. Genetic Algorithm (GA method was proposed to optimise the process parameters that would result in optimal solutions of optimisation goals. Using the GA, the shrinkage of the thick plate part was improved by 39.1% in parallel direction and 17.21% in the normal direction of melt flow.

Ultra low-K shrinkage behavior when under electron beam in a scanning electron microscope

Energy Technology Data Exchange (ETDEWEB)

Lorut, F.; Imbert, G. [ST Microelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex (France); Roggero, A. [Centre National d' Etudes Spatiales, 18 Avenue Edouard Belin, 31400 Toulouse (France)

2013-08-28

In this paper, we investigate the tendency of porous low-K dielectrics (also named Ultra Low-K, ULK) behavior to shrink when exposed to the electron beam of a scanning electron microscope. Various experimental electron beam conditions have been used for irradiating ULK thin films, and the resulting shrinkage has been measured through use of an atomic force microscope tool. We report the shrinkage to be a fast, cumulative, and dose dependent effect. Correlation of the shrinkage with incident electron beam energy loss has also been evidenced. The chemical modification of the ULK films within the interaction volume has been demonstrated, with a densification of the layer and a loss of carbon and hydrogen elements being observed.

Toward Generalization of Iterative Small Molecule Synthesis.

Science.gov (United States)

Lehmann, Jonathan W; Blair, Daniel J; Burke, Martin D

2018-02-01

Small molecules have extensive untapped potential to benefit society, but access to this potential is too often restricted by limitations inherent to the customized approach currently used to synthesize this class of chemical matter. In contrast, the "building block approach", i.e., generalized iterative assembly of interchangeable parts, has now proven to be a highly efficient and flexible way to construct things ranging all the way from skyscrapers to macromolecules to artificial intelligence algorithms. The structural redundancy found in many small molecules suggests that they possess a similar capacity for generalized building block-based construction. It is also encouraging that many customized iterative synthesis methods have been developed that improve access to specific classes of small molecules. There has also been substantial recent progress toward the iterative assembly of many different types of small molecules, including complex natural products, pharmaceuticals, biological probes, and materials, using common building blocks and coupling chemistry. Collectively, these advances suggest that a generalized building block approach for small molecule synthesis may be within reach.

Experimental drying shrinkage of hardened cement pastes as a function of relative humidity

DEFF Research Database (Denmark)

Hansen, Kurt Kielsgaard; Baroghel, V.B.

1996-01-01

The results of an experimental study concerning drying shrinkage measured as a function of relative humidity on thin specimens of mature hardened cement pastes are presented. The results obtained at two laboratories are compared.......The results of an experimental study concerning drying shrinkage measured as a function of relative humidity on thin specimens of mature hardened cement pastes are presented. The results obtained at two laboratories are compared....

Influence of Aggregate Wettability with Different Lithology Aggregates on Concrete Drying Shrinkage

Directory of Open Access Journals (Sweden)

Yuanchen Guo

2015-01-01

Full Text Available The correlation of the wettability of different lithology aggregates and the drying shrinkage of concrete materials is studied, and some influential factors such as wettability and wetting angle are analyzed. A mercury porosimeter is used to measure the porosities of different lithology aggregates accurately, and the pore size ranges that significantly affect the drying shrinkage of different lithology aggregate concretes are confirmed. The pore distribution curve of the different coarse aggregates is also measured through a statistical method, and the contact angle of different coarse aggregates and concrete is calculated according to the linear fitting relationship. Research shows that concrete strength is determined by aggregate strength. Aggregate wettability is not directly correlated with concrete strength, but wettability significantly affects concrete drying shrinkage. In all types’ pores, the greatest impacts on wettability are capillary pores and gel pores, especially for the pores of the size locating 2.5–50 nm and 50–100 nm two ranges.

Temperature dependence of autogenous shrinkage of silica fume cement pastes with a very low water–binder ratio

Energy Technology Data Exchange (ETDEWEB)

Maruyama, I., E-mail: ippei@dali.nuac.nagoya-u.ac.jp [Graduate School of Environmental Studies, Nagoya University, ES Building, No. 539, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Teramoto, A. [Graduate School of Environmental Studies, Nagoya University, Faculty of Engineering, ES Building, No. 546, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2013-08-15

Ultra-high-strength concrete with a large unit cement content undergoes considerable temperature increase inside members due to hydration heat, leading to a higher risk of internal cracking. Hence, the temperature dependence of autogenous shrinkage of cement pastes made with silica fume premixed cement with a water–binder ratio of 0.15 was studied extensively. Development of autogenous shrinkage showed different behaviors before and after the inflection point, and dependence on the temperature after mixing and subsequent temperature histories. The difference in autogenous shrinkage behavior poses problems for winter construction because autogenous shrinkage may increase with decrease in temperature after mixing before the inflection point and with increase in temperature inside concrete members with large cross sections.

Temperature dependence of autogenous shrinkage of silica fume cement pastes with a very low water–binder ratio

International Nuclear Information System (INIS)

Maruyama, I.; Teramoto, A.

2013-01-01

Ultra-high-strength concrete with a large unit cement content undergoes considerable temperature increase inside members due to hydration heat, leading to a higher risk of internal cracking. Hence, the temperature dependence of autogenous shrinkage of cement pastes made with silica fume premixed cement with a water–binder ratio of 0.15 was studied extensively. Development of autogenous shrinkage showed different behaviors before and after the inflection point, and dependence on the temperature after mixing and subsequent temperature histories. The difference in autogenous shrinkage behavior poses problems for winter construction because autogenous shrinkage may increase with decrease in temperature after mixing before the inflection point and with increase in temperature inside concrete members with large cross sections

Wall conditioning for ITER: Current experimental and modeling activities

Energy Technology Data Exchange (ETDEWEB)

Douai, D., E-mail: david.douai@cea.fr [CEA, IRFM, Association Euratom-CEA, 13108 St. Paul lez Durance (France); Kogut, D. [CEA, IRFM, Association Euratom-CEA, 13108 St. Paul lez Durance (France); Wauters, T. [LPP-ERM/KMS, Association Belgian State, 1000 Brussels (Belgium); Brezinsek, S. [FZJ, Institut für Energie- und Klimaforschung Plasmaphysik, 52441 Jülich (Germany); Hagelaar, G.J.M. [Laboratoire Plasma et Conversion d’Energie, UMR5213, Toulouse (France); Hong, S.H. [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Lomas, P.J. [CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Lyssoivan, A. [LPP-ERM/KMS, Association Belgian State, 1000 Brussels (Belgium); Nunes, I. [Associação EURATOM-IST, Instituto de Plasmas e Fusão Nuclear, 1049-001 Lisboa (Portugal); Pitts, R.A. [ITER International Organization, F-13067 St. Paul lez Durance (France); Rohde, V. [Max-Planck-Institut für Plasmaphysik, 85748 Garching (Germany); Vries, P.C. de [ITER International Organization, F-13067 St. Paul lez Durance (France)

2015-08-15

Wall conditioning will be required in ITER to control fuel and impurity recycling, as well as tritium (T) inventory. Analysis of conditioning cycle on the JET, with its ITER-Like Wall is presented, evidencing reduced need for wall cleaning in ITER compared to JET–CFC. Using a novel 2D multi-fluid model, current density during Glow Discharge Conditioning (GDC) on the in-vessel plasma-facing components (PFC) of ITER is predicted to approach the simple expectation of total anode current divided by wall surface area. Baking of the divertor to 350 °C should desorb the majority of the co-deposited T. ITER foresees the use of low temperature plasma based techniques compatible with the permanent toroidal magnetic field, such as Ion (ICWC) or Electron Cyclotron Wall Conditioning (ECWC), for tritium removal between ITER plasma pulses. Extrapolation of JET ICWC results to ITER indicates removal comparable to estimated T-retention in nominal ITER D:T shots, whereas GDC may be unattractive for that purpose.

U.S. contributions to ITER

International Nuclear Information System (INIS)

Sauthoff, Ned R.

2006-01-01

The United States participates in the ITER project to undertake the study of the science and technology of burning plasmas. The 2003 U.S. decision to enter the ITER negotiations followed an extensive series of community and governmental reviews of the benefits, readiness, and approaches to the study of burning plasmas. This paper describes both the technical and the organizational preparations and plans for U.S. participation in the ITER construction activity: in-kind contributions, staff contributions, and cash contributions as well as supporting physics and technology research. Near-term technical activities focus on the completion of R and D and design and mitigation of risks in the areas of provisionally assigned US contributions. Outside the project, the U.S. is engaged in preparations for the test blanket module program. Organizational activities focus on preparations of the project management arrangements to maximize the overall success of the ITER project: elements include refinement of U.S. positions on the international arrangements, the establishment of the U.S. Domestic Agency, progress along the path of the U.S. Department of Energy's Project Management Order, and overall preparations for commencement of the fabrication of major items of equipment and for provision of staff and cash as specified in the upcoming ITER agreement

Photo-crosslinkable cyanoacrylate bioadhesive: shrinkage kinetics, dynamic mechanical properties, and biocompatibility of adhesives containing TMPTMA and POSS nanostructures as crosslinking agents.

Science.gov (United States)

Ghasaban, S; Atai, M; Imani, M; Zandi, M; Shokrgozar, M-A

2011-11-01

The study investigates the photo-polymerization shrinkage behavior, dynamic mechanical properties, and biocompatibility of cyanoacrylate bioadhesives containing POSS nanostructures and TMPTMA as crosslinking agents. Adhesives containing 2-octyl cyanoacrylate (2-OCA) and different percentages of POSS nanostructures and TMPTMA as crosslinking agents were prepared. The 1-phenyl-1, 2-propanedione (PPD) was incorporated as photo-initiator into the adhesive in 1.5, 3, and 4 wt %. The shrinkage strain of the specimens was measured using bonded-disk technique. Shrinkage strain, shrinkage strain rate, maximum and time at maximum shrinkage strain rate were measured and compared. Mechanical properties of the adhesives were also studied using dynamic mechanical thermal analysis (DMTA). Biocompatibility of the adhesives was examined by MTT method. The results showed that shrinkage strain increased with increasing the initiator concentration up to 3 wt % in POSS-containing and 1.5 wt % in TMPTMA-containing specimens and plateaued out at higher concentrations. By increasing the crosslinking agent, shrinkage strain, and shrinkage strain rate increased and the time at maximum shrinkage strain rate decreased. The study indicates that the incorporation of crosslinking agents into the cyanoacrylate adhesives resulted in improved mechanical properties. Preliminary MTT studies also revealed better biocompatibility profile for the adhesives containing crosslinking agents comparing to the neat specimens. Copyright © 2011 Wiley Periodicals, Inc.

The Influence of Water Sorption of Dental Light-Cured Composites on Shrinkage Stress

Directory of Open Access Journals (Sweden)

Kinga Bociong

2017-09-01

Full Text Available The contraction stress generated during the photopolymerization of resin dental composites is the major disadvantage. The water sorption in the oral environment should counteract the contraction stress. The purpose was to evaluate the influence of the water sorption of composite materials on polymerization shrinkage stress generated at the restoration-tooth interface. The following materials were tested: Filtek Ultimate, Gradia Direct LoFlo, Heliomolar Flow, Tetric EvoCeram, Tetric EvoCeram Bulk Fill, Tetric EvoFlow, Tetric EvoFlow Bulk Fill, X-tra Base, Venus BulkFil, and Ceram.X One. The shrinkage stress was measured immediately after curing and after: 0.5 h, 24 h, 72 h, 96 h, 168 h, 240 h, 336 h, 504 h, 672 h, and 1344 h by means of photoelastic study. Moreover, water sorption and solubility were evaluated. Material samples were weighted on scale in time intervals to measure the water absorbency and the dynamic of this process. The tested materials during polymerization generated shrinkage stresses ranging from 6.3 MPa to 12.5 MPa. Upon water conditioning (56 days, the decrease in shrinkage strain (not less than 48% was observed. The decrease in value stress in time is material-dependent.

Ultrasonic assessment of shrinkage type discontinuities

International Nuclear Information System (INIS)

Hubber, John

2010-01-01

This investigation into ultrasonic internal discontinuities is intended to demonstrate typical examples of internal 'shrinkage' type discontinuities and its connection with the casting suitability, integrity and reliability in service. This type of discontinuity can be misinterpreted by ultrasonic technicians and can lead to the rejection of castings unnecessarily, due to the mis-characterization of fine shrinkage - discrete porosity. The samples for this investigation were taken from thirty ton heavy section ductile iron mill flange castings, manufactured by Graham Campbell Ferrum International. The sampled area was of discontinuities that were recorded for sizing on an area due to loss of back wall echo, but had acceptable reflectivity. A comparative sample was taken adjacent to the area of discrete porosity. The discontinuities found by this investigation are of a 'spongy' type, gaseous in appearance and are surrounded by acoustically sound material. All discontinuities discussed in this paper are centrally located in the through thickness of the casting. The porous nature of this type of discontinuity consisting of approximately 80-90% metal has its own residual strength, as indicated by the proof stress results which reveal a residual strength of up to 50-60% of that of the unaffected area of the casting. The affected areas are elliptical in shape and vary in density and through thickness throughout.

An iterative approach for the optimization of pavement maintenance management at the network level.

Science.gov (United States)

Torres-Machí, Cristina; Chamorro, Alondra; Videla, Carlos; Pellicer, Eugenio; Yepes, Víctor

2014-01-01

Pavement maintenance is one of the major issues of public agencies. Insufficient investment or inefficient maintenance strategies lead to high economic expenses in the long term. Under budgetary restrictions, the optimal allocation of resources becomes a crucial aspect. Two traditional approaches (sequential and holistic) and four classes of optimization methods (selection based on ranking, mathematical optimization, near optimization, and other methods) have been applied to solve this problem. They vary in the number of alternatives considered and how the selection process is performed. Therefore, a previous understanding of the problem is mandatory to identify the most suitable approach and method for a particular network. This study aims to assist highway agencies, researchers, and practitioners on when and how to apply available methods based on a comparative analysis of the current state of the practice. Holistic approach tackles the problem considering the overall network condition, while the sequential approach is easier to implement and understand, but may lead to solutions far from optimal. Scenarios defining the suitability of these approaches are defined. Finally, an iterative approach gathering the advantages of traditional approaches is proposed and applied in a case study. The proposed approach considers the overall network condition in a simpler and more intuitive manner than the holistic approach.

An Iterative Approach for the Optimization of Pavement Maintenance Management at the Network Level

Directory of Open Access Journals (Sweden)

Cristina Torres-Machí

2014-01-01

Full Text Available Pavement maintenance is one of the major issues of public agencies. Insufficient investment or inefficient maintenance strategies lead to high economic expenses in the long term. Under budgetary restrictions, the optimal allocation of resources becomes a crucial aspect. Two traditional approaches (sequential and holistic and four classes of optimization methods (selection based on ranking, mathematical optimization, near optimization, and other methods have been applied to solve this problem. They vary in the number of alternatives considered and how the selection process is performed. Therefore, a previous understanding of the problem is mandatory to identify the most suitable approach and method for a particular network. This study aims to assist highway agencies, researchers, and practitioners on when and how to apply available methods based on a comparative analysis of the current state of the practice. Holistic approach tackles the problem considering the overall network condition, while the sequential approach is easier to implement and understand, but may lead to solutions far from optimal. Scenarios defining the suitability of these approaches are defined. Finally, an iterative approach gathering the advantages of traditional approaches is proposed and applied in a case study. The proposed approach considers the overall network condition in a simpler and more intuitive manner than the holistic approach.

Characterization of a sequential pipeline approach to automatic tissue segmentation from brain MR Images

International Nuclear Information System (INIS)

Hou, Zujun; Huang, Su

2008-01-01

Quantitative analysis of gray matter and white matter in brain magnetic resonance imaging (MRI) is valuable for neuroradiology and clinical practice. Submission of large collections of MRI scans to pipeline processing is increasingly important. We characterized this process and suggest several improvements. To investigate tissue segmentation from brain MR images through a sequential approach, a pipeline that consecutively executes denoising, skull/scalp removal, intensity inhomogeneity correction and intensity-based classification was developed. The denoising phase employs a 3D-extension of the Bayes-Shrink method. The inhomogeneity is corrected by an improvement of the Dawant et al.'s method with automatic generation of reference points. The N3 method has also been evaluated. Subsequently the brain tissue is segmented into cerebrospinal fluid, gray matter and white matter by a generalized Otsu thresholding technique. Intensive comparisons with other sequential or iterative methods have been carried out using simulated and real images. The sequential approach with judicious selection on the algorithm selection in each stage is not only advantageous in speed, but also can attain at least as accurate segmentation as iterative methods under a variety of noise or inhomogeneity levels. A sequential approach to tissue segmentation, which consecutively executes the wavelet shrinkage denoising, scalp/skull removal, inhomogeneity correction and intensity-based classification was developed to automatically segment the brain tissue into CSF, GM and WM from brain MR images. This approach is advantageous in several common applications, compared with other pipeline methods. (orig.)

Design of the ITER magnets to provide plasma operational flexibility

International Nuclear Information System (INIS)

Mitchell, N.; Bessette, D.; Ferrari, M.; Huguet, M.; Jong, C.; Takahashi, Y.; Yoshida, K.; Maix, R.; Krivchenkov, Y.; Zapretilina, E.

2005-01-01

The ITER magnets have been optimised and refined since the ITER Final Design Report (FDR) in 2001. Multiple design options have been eliminated and there is improved ability to drive a wide range of plasma configurations. Design iterations on the TF out of plane supports have eliminated stress concentrations in the inner keyways and have led to the choice of a so called friction-joint on the outside. The closure procedure for the TF case has been changed, with a new case segmentation, less risk of winding pack damage from shrinkage and better filling of the case-winding gaps. Selection of compact joints for the CS has enabled the peak field and cyclic stress levels in the conductor to be reduced while maintaining the flux capability. The uncertainty in the nuclear heat levels in the inner legs of the TF coils, and the need to operate with plasma nuclear powers from 360 to 700MW, lead to a thermal screen on the inside of the case with variable cooling capability. The electrical insulation specification has been refined after irradiation test results to give a better margin on the onset of degradation after operation to 3MWa/m 2 . The RWM stabilisation provided by the side CC has been extended by accepting higher voltages and heating from AC losses. R and D results from the model coil tests have shown lower than expected design margins for the Nb3Sn conductors. This has been offset by adopting the latest advances in strand performance, and the margins of the new conductor will be confirmed by testing in 2005. Preparation for procurement is underway with considerations on technically acceptable ways of splitting the magnet supply. (author)

Regional Brain Shrinkage over Two Years: Individual Differences and Effects of Pro-Inflammatory Genetic Polymorphisms

Science.gov (United States)

Persson, N.; Ghisletta, P.; Dahle, C.L.; Bender, A.R.; Yang, Y.; Yuan, P.; Daugherty, A.M.; Raz, N.

2014-01-01

We examined regional changes in brain volume in healthy adults (N = 167, age 19-79 years at baseline; N = 90 at follow-up) over approximately two years. With latent change score models, we evaluated mean change and individual differences in rates of change in 10 anatomically-defined and manually-traced regions of interest (ROIs): lateral prefrontal cortex (LPFC), orbital frontal cortex (OF), prefrontal white matter (PFw), hippocampus (HC), parahippocampal gyrus (PhG), caudate nucleus (Cd), putamen (Pt), insula (In), cerebellar hemispheres (CbH), and primary visual cortex (VC). Significant mean shrinkage was observed in the HC, CbH, In, OF, and the PhG, and individual differences in change were noted in all regions, except the OF. Pro-inflammatory genetic variants mediated shrinkage in PhG and CbH. Carriers of two T alleles of interleukin-1β (IL-1βC-511T, rs16944) and a T allele of methylenetetrahydrofolate reductase (MTHFRC677T, rs1801133) polymorphisms showed increased PhG shrinkage. No effects of a pro-inflammatory polymorphism for C-reactive protein (CRP-286C>A>T, rs3091244) or apolipoprotein (APOE) ε4 allele were noted. These results replicate the pattern of brain shrinkage observed in previous studies, with a notable exception of the LPFC thus casting doubt on the unique importance of prefrontal cortex in aging. Larger baseline volumes of CbH and In were associated with increased shrinkage, in conflict with the brain reserve hypothesis. Contrary to previous reports, we observed no significant linear effects of age and hypertension on regional brain shrinkage. Our findings warrant further investigation of the effects of neuroinflammation on structural brain change throughout the lifespan. PMID:25264227

Welding feasibility study of U-shape lips at ITER Port-Plug with new laser beam sources

Energy Technology Data Exchange (ETDEWEB)

Behr, W., E-mail: w.behr@fz-juelich.de; Faidel, D.; Fischer, K.; Pap, M.; Offermanns, G.

2013-10-15

A “Cut and weld feasibility study of U shape lips” shown on June 2007 was initial of the following investigations. A new solution for Port Plug sealing at ITER was demanded and the experience in laser beam welding of the ZAT (Central Institute of Technology) in Jülich (Research Centre Jülich) offered an alternative solution. Up to now mechanically fixed sealing or sealing by TIG welding is used with typical benefits and problems, as heat input, shrinkage or limited room for tools. New disc-laser application for tight welding (leakage rate < 10{sup −9} mbar l/s) of the sealing lips is presented in the following. Both in the metallographic investigation and by means of leakage rate investigation the suitability of the selected procedure as seal alternative at the ITER Port Plug could be pointed out. The distance between two connections can be reduced to approx. 5 mm. The presented milling process for weld seam removal offers an option additionally to laser beam cutting. Final tests with a new disc-laser source offered additional benefits concerning seam quality, process stability and seam geometry. The distance between two connections will be reduced to less than 3 mm in next investigations. Construction unit near investigations and a demo part in original size underline finally the industrial suitability of the laser-welding-process for Port-Plug sealing at ITER.

Iterative Prototyping of Strategy Implementation Workshop Design

DEFF Research Database (Denmark)

Kryger, Anders

2018-01-01

Purpose: The purpose of this paper is to demonstrate how a strategy implementation workshop design can be developed and tested while minimizing the time spent on developing the design. Design/methodology/approach: This multiple case study at a diesel engine company shows how iterative prototyping...... can be used to structure the design process of a strategy implementation workshop. Findings: Strategy implementation workshop design can be developed in resource-constrained environments through iterative prototyping of the workshop design. Each workshop iteration can generate value in its own right...... draw on his/her experience as well as add to his/her knowledge base. Originality/value: Introducing iterative prototyping in an organizational context can facilitate fast yet structured development of a rigorous workshop design. Strategy consultants are provided with empirical examples of how...

Mechanical design and construction qualification program on ITER correction coils structures

Energy Technology Data Exchange (ETDEWEB)

Foussat, A., E-mail: arnaud.foussat@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Weiyue, Wu; Jing, Wei; Shuangsong, Du [Academy of Science Institute of Plasma Physics, PO 1126, Hefei, Anhui 230031 (China); Sgobba, S. [European Center for Nuclear Research, CH-1211 Geneva 23 (Switzerland); Hongwei, Li [China International Nuclear Fusion Energy Program Execution Center, Ministry of Science and Technology, 15B Fuxing Rd., Beijing 100862 (China); Libeyre, Paul; Jong, Cornelis; Klofac, Kamil; Mitchell, Neil [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

2014-04-01

The ITER Magnet system consists of 4 main coils sub-systems, i.e. 18 toroidal field coils (TFC), a central solenoid (CS), 6 poloidal field coils (PF) and 3 sets of correction coils (CC). The ITER fusion project has selected the stainless steel 316LN as main material for the magnet structure. The CC contribute to reducing the range of magnetic error fields created by imperfections in the location and geometry of the other coils used to confine, heat, and shape the plasma. During plasma operation, a large number of loading condition scenarios have been considered and structural analysis performed on key items like Cable-In-Conduit Conductor and the coil case. The results obtained are used for both static and fatigue structural assessment defining the present baseline design. For the construction of the structural cases, welding techniques such as GTAW (Gas Tungsten Arc Welding) and techniques resulting in low distortion and shrinkage like EBW (Electron Beam Welding) or Laser Beam Welding (LBW) with filler metal wire have been selected. Those methods are considered for future qualifications to guarantee proper weld parameters and specified weld properties. In order to determine the strength and fracture toughness of 316LN stainless steel welds with respect to design criteria, some mechanical tests have been carried out at 7 K (or 77 K), and room temperature.

Effects of molecular structure of the resins on the volumetric shrinkage and the mechanical strength of dental restorative composites.

Science.gov (United States)

Kim, L U; Kim, J W; Kim, C K

2006-09-01

To prepare a dental composite that has a low amount of curing shrinkage and excellent mechanical strength, various 2,2-bis[4-(2-hydroxy-3-methacryloyloxy propoxy) phenyl] propane (Bis-GMA) derivatives were synthesized via molecular structure design, and afterward, properties of their mixtures were explored. Bis-GMA derivatives, which were obtained by substituting methyl groups for hydrogen on the phenyl ring in the Bis-GMA, exhibited lower curing shrinkage than Bis-GMA, whereas their viscosities were higher than that of Bis-GMA. Other Bis-GMA derivatives, which contained a glycidyl methacrylate as a molecular end group exhibited reduced curing shrinkage and viscosity. Methoxy substitution for hydroxyl groups on the Bis-GMA derivatives was performed for the further reduction of the viscosity and curing shrinkage. Various resin mixtures, which had the same viscosity as the commercial one, were prepared, and their curing shrinkage was examined. A resin mixture containing 2,2-bis[3,5-dimethyl, 4-(2-methoxy-3-methacryloyloxy propoxy) phenyl] propane] (TMBis-M-GMA) as a base resin and 4-tert-butylphenoxy-2-methyoxypropyl methacrylate (t-BP-M-GMA) as a diluent exhibited the lowest curing shrinkage among them. The composite prepared from this resin mixture also exhibited the lowest curing shrinkage along with enhanced mechanical properties.

A Mesoscopic Simulation for the Early-Age Shrinkage Cracking Process of High Performance Concrete in Bridge Engineering

Directory of Open Access Journals (Sweden)

Guodong Li

2017-01-01

Full Text Available On a mesoscopic level, high performance concrete (HPC was assumed to be a heterogeneous composite material consisting of aggregates, mortar, and pores. The concrete mesoscopic structure model had been established based on CT image reconstruction. By combining this model with continuum mechanics, damage mechanics, and fracture mechanics, a relatively complete system for concrete mesoscopic mechanics analysis was established to simulate the process of early-age shrinkage cracking in HPC. This process was based on the dispersion crack model. The results indicated that the interface between the aggregate and mortar was the crack point caused by shrinkage cracks in HPC. The locations of early-age shrinkage cracks in HPC were associated with the spacing and the size of the aggregate particle. However, the shrinkage deformation size of the mortar was related to the scope of concrete cracking and was independent of the crack position. Whereas lower water to cement ratios can improve the early strength of concrete, this ratio cannot control early-age shrinkage cracks in HPC.

Conjugation of diisocyanate side chains to dimethacrylate reduces polymerization shrinkage and increases the hardness of composite resins.

Science.gov (United States)

Jan, Yih-Dean; Lee, Bor-Shiunn; Lin, Chun-Pin; Tseng, Wan-Yu

2014-04-01

Polymerization shrinkage is one of the main causes of dental restoration failure. This study tried to conjugate two diisocyanate side chains to dimethacrylate resins in order to reduce polymerization shrinkage and increase the hardness of composite resins. Diisocyanate, 2-hydroxyethyl methacrylate, and bisphenol A dimethacrylate were reacted in different ratios to form urethane-modified new resin matrices, and then mixed with 50 wt.% silica fillers. The viscosities of matrices, polymerization shrinkage, surface hardness, and degrees of conversion of experimental composite resins were then evaluated and compared with a non-modified control group. The viscosities of resin matrices increased with increasing diisocyanate side chain density. Polymerization shrinkage and degree of conversion, however, decreased with increasing diisocyanate side chain density. The surface hardness of all diisocyanate-modified groups was equal to or significantly higher than that of the control group. Conjugation of diisocyanate side chains to dimethacrylate represents an effective means of reducing polymerization shrinkage and increasing the surface hardness of dental composite resins. Copyright © 2012. Published by Elsevier B.V.

SHRINKAGE REDUCTION AND CRACK PREVENTION OF ALKALI-ACTIVATED PHOSPHOROUS SLAG CEMENT

Directory of Open Access Journals (Sweden)

Yanan Wang

2016-05-01

Full Text Available The effects of fly ash, calcium oxide and polypropylene fiber on the physical and mechanical properties, shrinkage and cracking behaviors of alkali-activated phosphorous slag cement (AA-PS-C were studied. The results show that replacing 10-15% phosphorous slag by fly ash and adding calcium oxide as an expansive agent reduce the shrinkage of AA-PS-C. Fly ash will increase the flexural strength, although the compressive strength will be slightly decreased, while the calcium oxide expansive agent coated with aluminum stearate will slightly shorten the setting time and reduce the strength. Adding polypropylene fiber can greatly increase the crack-resistance of AA-PS-C.

Evaluation of the polymerization shrinkage of experimental flowable composite resins through optical coherence tomography

Science.gov (United States)

Carneiro, Vanda S. M.; Mota, Cláudia C. B. O.; Souza, Alex F.; Cajazeira, Marlus R. R.; Gerbi, Marleny E. M. M.; Gomes, Anderson S. L.

2018-02-01

This study evaluated the polymerization shrinkage of two experimental flowable composite resins (CR) with different proportions of Urethane dimethacrylate (UDMA)/triethylene glycol dimethacrylate (TEGDMA) monomers in the organic matrix (50:50 and 60:40, respectively). A commercially available flowable CR, Tetric N-Flow (Ivoclair Vivadent, Liechtenstein, Germany), was employed as the control group. The resins were inserted in a cylindrical teflon mold (7 mm diameter, 0.6 mm height) and scanned with OCT before photoactivation, immediately after and 15 minutes after light-curing (Radii-Cal, SDI, Australia, 1,200 mW/cm2 ) exposure. A Callisto SD-OCT system (Thorlabs Inc, USA), operating at 930 nm central wavelength was employed for imaging acquisition. Cross-sectional OCT images were captured with 8 mm transverse scanning (2000x512 matrix), and processed by the ImageJ software, for comparison between the scanning times and between groups. Pearson correlation showed significant shrinkage for all groups in each time analyzed. Kruskal-Wallis test showed greater polymerization shrinkage for the 50:50 UDMA/TEGDMA group (p=0.001), followed by the control group (p=0.018). TEGDMA concentration was proportionally related to the polymerization shrinkage of the flowable composite resins.

Iterative absolute electroanalytical approach to characterization of bulk redox conducting systems.

Science.gov (United States)

Lewera, Adam; Miecznikowski, Krzysztof; Chojak, Malgorzata; Makowski, Oktawian; Golimowski, Jerzy; Kulesza, Pawel J

2004-05-15

A novel electroanalytical approach is proposed here, and it is demonstrated with the direct and simultaneous determination of two unknowns: the concentration of redox sites and the apparent diffusion coefficient for charge propagation in a single crystal of dodecatungstophosphoric acid. This Keggin-type polyoxometalate serves as a model bulk redox conducting inorganic material for solid-state voltammetry. The system has been investigated using an ultramicrodisk working electrode in the absence of external liquid supporting electrolyte. The analytical method requires numerical solution of the combination of two equations in which the first one describes current (or charge) in a well-defined (either spherical or linear) diffusional regime and the second general equation describes chronoamperometric (or normal pulse voltammetric current) under mixed (linear-spherical) conditions. The iterative approach is based on successive approximations through calculation and minimizing the least-squares error function. The method is fairly universal, and in principle, it can be extended to the investigation of other bulk systems including sol-gel processed materials, redox melts, and solutions on condition that they are electroactive and well behaved, they contain redox centers at sufficiently high level, and a number of electrons for the redox reaction considered is known.

Investigation on Failures of Composite Beam and Substrate Concrete due to Drying Shrinkage Property of Repair Materials

Science.gov (United States)

Pattnaik, Rashmi Ranjan

2017-06-01

A Finite Element Analysis (FEA) and an experimental study was conducted on composite beam of repair material and substrate concrete to investigate the failures of the composite beam due to drying shrinkage property of the repair materials. In FEA, the stress distribution in the composite beam due to two concentrate load and shrinkage of repair materials were investigated in addition to the deflected shape of the composite beam. The stress distributions and load deflection shapes of the finite element model were investigated to aid in analysis of the experimental findings. In the experimental findings, the mechanical properties such as compressive strength, split tensile strength, flexural strength, and load-deflection curves were studied in addition to slant shear bond strength, drying shrinkage and failure patterns of the composite beam specimens. Flexure test was conducted to simulate tensile stress at the interface between the repair material and substrate concrete. The results of FEA were used to analyze the experimental results. It was observed that the repair materials with low drying shrinkage are showing compatible failure in the flexure test of the composite beam and deform adequately in the load deflection curves. Also, the flexural strength of the composite beam with low drying shrinkage repair materials showed higher flexural strength as compared to the composite beams with higher drying shrinkage value of the repair materials even though the strength of those materials were more.

The evolution of shrinkage strain of pet-mortar composite eco ...

African Journals Online (AJOL)

... resulting from the cement hydration and are governed by various physical and ... of PET volumetric additive amounts for cement substituting and for the behavior ... Keywords: Composite Eco-materials; Cement substitution; Shrinkage strain; ...

AIR-MRF: Accelerated iterative reconstruction for magnetic resonance fingerprinting.

Science.gov (United States)

Cline, Christopher C; Chen, Xiao; Mailhe, Boris; Wang, Qiu; Pfeuffer, Josef; Nittka, Mathias; Griswold, Mark A; Speier, Peter; Nadar, Mariappan S

2017-09-01

Existing approaches for reconstruction of multiparametric maps with magnetic resonance fingerprinting (MRF) are currently limited by their estimation accuracy and reconstruction time. We aimed to address these issues with a novel combination of iterative reconstruction, fingerprint compression, additional regularization, and accelerated dictionary search methods. The pipeline described here, accelerated iterative reconstruction for magnetic resonance fingerprinting (AIR-MRF), was evaluated with simulations as well as phantom and in vivo scans. We found that the AIR-MRF pipeline provided reduced parameter estimation errors compared to non-iterative and other iterative methods, particularly at shorter sequence lengths. Accelerated dictionary search methods incorporated into the iterative pipeline reduced the reconstruction time at little cost of quality. Copyright © 2017 Elsevier Inc. All rights reserved.

Analysis of the shrinkage at the thick plate part using response surface methodology

Science.gov (United States)

Hatta, N. M.; Azlan, M. Z.; Shayfull, Z.; Roselina, S.; Nasir, S. M.

2017-09-01

Injection moulding is well known for its manufacturing process especially in producing plastic products. To measure the final product quality, there are lots of precautions to be taken into such as parameters setting at the initial stage of the process. Sometimes, if these parameters were set up wrongly, defects may be occurred and one of the well-known defects in the injection moulding process is a shrinkage. To overcome this problem, a maximisation at the precaution stage by making an optimal adjustment on the parameter setting need to be done and this paper focuses on analysing the shrinkage by optimising the parameter at thick plate part with the help of Response Surface Methodology (RSM) and ANOVA analysis. From the previous study, the outstanding parameter gained from the optimisation method in minimising the shrinkage at the moulded part was packing pressure. Therefore, with the reference from the previous literature, packing pressure was selected as the parameter setting for this study with other three parameters which are melt temperature, cooling time and mould temperature. The analysis of the process was obtained from the simulation by Autodesk Moldflow Insight (AMI) software and the material used for moulded part was Acrylonitrile Butadiene Styrene (ABS). The analysis and result were obtained and it found that the shrinkage can be minimised and the significant parameters were found as packing pressure, mould temperature and melt temperature.

Effect of processing conditions on shrinkage in injection moulding

NARCIS (Netherlands)

Jansen, K.M.B.; van Dijk, D.J.; Husselman, M.H.

1998-01-01

A systematic study on the effect of processing conditions on mold shrinkage was undertaken for seven common thermoplastic polymers. It turned out that the holding pressure was always the key parameter. The effect of the melt temperature is slightly less important. Injection velocity and mold

Shrinkage of Newly Formed Particles in an Urban Environment

Czech Academy of Sciences Publication Activity Database

Škrabalová, Lenka; Zíková, Naděžda; Ždímal, Vladimír

2015-01-01

Roč. 15, č. 4 (2015), s. 1313-1324 ISSN 1680-8584 R&D Projects: GA ČR GAP209/11/1342 Institutional support: RVO:67985858 Keywords : aerosol dynamics * ultrafine particles * particle shrinkage Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.393, year: 2015

A novel iterative scheme and its application to differential equations.

Science.gov (United States)

Khan, Yasir; Naeem, F; Šmarda, Zdeněk

2014-01-01

The purpose of this paper is to employ an alternative approach to reconstruct the standard variational iteration algorithm II proposed by He, including Lagrange multiplier, and to give a simpler formulation of Adomian decomposition and modified Adomian decomposition method in terms of newly proposed variational iteration method-II (VIM). Through careful investigation of the earlier variational iteration algorithm and Adomian decomposition method, we find unnecessary calculations for Lagrange multiplier and also repeated calculations involved in each iteration, respectively. Several examples are given to verify the reliability and efficiency of the method.

Shrinkage-based diagonal Hotelling’s tests for high-dimensional small sample size data

KAUST Repository

Dong, Kai

2015-09-16

DNA sequencing techniques bring novel tools and also statistical challenges to genetic research. In addition to detecting differentially expressed genes, testing the significance of gene sets or pathway analysis has been recognized as an equally important problem. Owing to the “large pp small nn” paradigm, the traditional Hotelling’s T2T2 test suffers from the singularity problem and therefore is not valid in this setting. In this paper, we propose a shrinkage-based diagonal Hotelling’s test for both one-sample and two-sample cases. We also suggest several different ways to derive the approximate null distribution under different scenarios of pp and nn for our proposed shrinkage-based test. Simulation studies show that the proposed method performs comparably to existing competitors when nn is moderate or large, but it is better when nn is small. In addition, we analyze four gene expression data sets and they demonstrate the advantage of our proposed shrinkage-based diagonal Hotelling’s test.

Shrinkage-based diagonal Hotelling’s tests for high-dimensional small sample size data

KAUST Repository

Dong, Kai; Pang, Herbert; Tong, Tiejun; Genton, Marc G.

2015-01-01

DNA sequencing techniques bring novel tools and also statistical challenges to genetic research. In addition to detecting differentially expressed genes, testing the significance of gene sets or pathway analysis has been recognized as an equally important problem. Owing to the “large pp small nn” paradigm, the traditional Hotelling’s T2T2 test suffers from the singularity problem and therefore is not valid in this setting. In this paper, we propose a shrinkage-based diagonal Hotelling’s test for both one-sample and two-sample cases. We also suggest several different ways to derive the approximate null distribution under different scenarios of pp and nn for our proposed shrinkage-based test. Simulation studies show that the proposed method performs comparably to existing competitors when nn is moderate or large, but it is better when nn is small. In addition, we analyze four gene expression data sets and they demonstrate the advantage of our proposed shrinkage-based diagonal Hotelling’s test.

Marginal adaptation of a low-shrinkage silorane-based composite: A SEM-analysis

DEFF Research Database (Denmark)

Schmidt, Malene; Bindslev, Preben Hørsted; Poulsen, Sven

2012-01-01

shrinkage, has been marketed. Objective. To investigate whether reduced polymerization shrinkage improves the marginal adaptation of composite restorations. Material and methods. A total of 156 scanning electron microscopy (SEM) pictures (78 baseline, 78 follow-up) of the occlusal part of Class II......-casts of the restorations were used for SEM pictures at x 16 magnification. Pictures from baseline and follow-up (398 days, SD 29 days) were randomized and the examiner was blinded to the material and the age of the restoration. Stereologic measurements were used to calculate the length and the width of the marginal...

Experimental investigation on shrinkage and surface replication of injection moulded ceramic parts

DEFF Research Database (Denmark)

Islam, Aminul; Giannekas, Nikolaos; Marhöfer, David Maximilian

2014-01-01

Ceramic moulded parts are increasingly being used in advanced components and devices due to their unprecedented material and performance attributes. The surface finish, replication quality and material shrinkage are of immense importance for moulded ceramic parts intended for precision applications....... The current paper presents a thorough investigation on the process of ceramic moulding where it systematically characterizes the surface replication and shrinkage behaviours of precision moulded ceramic components. The test parts are moulded from Catamold TZP-A which is Y2O3-stabilised ZrO2 having widespread...... distribution for the moulded ceramic parts is presented....

A user-centered, iterative engineering approach for advanced biomass cookstove design and development

Science.gov (United States)

Shan, Ming; Carter, Ellison; Baumgartner, Jill; Deng, Mengsi; Clark, Sierra; Schauer, James J.; Ezzati, Majid; Li, Jiarong; Fu, Yu; Yang, Xudong

2017-09-01

Unclean combustion of solid fuel for cooking and other household energy needs leads to severe household air pollution and adverse health impacts in adults and children. Replacing traditional solid fuel stoves with high efficiency, low-polluting semi-gasifier stoves can potentially contribute to addressing this global problem. The success of semi-gasifier cookstove implementation initiatives depends not only on the technical performance and safety of the stove, but also the compatibility of the stove design with local cooking practices, the needs and preferences of stove users, and community economic structures. Many past stove design initiatives have failed to address one or more of these dimensions during the design process, resulting in failure of stoves to achieve long-term, exclusive use and market penetration. This study presents a user-centered, iterative engineering design approach to developing a semi-gasifier biomass cookstove for rural Chinese homes. Our approach places equal emphasis on stove performance and meeting the preferences of individuals most likely to adopt the clean stove technology. Five stove prototypes were iteratively developed following energy market and policy evaluation, laboratory and field evaluations of stove performance and user experience, and direct interactions with stove users. The most current stove prototype achieved high performance in the field on thermal efficiency (ISO Tier 3) and pollutant emissions (ISO Tier 4), and was received favorably by rural households in the Sichuan province of Southwest China. Among household cooks receiving the final prototype of the intervention stove, 88% reported lighting and using it at least once. At five months post-intervention, the semi-gasifier stoves were used at least once on an average of 68% [95% CI: 43, 93] of days. Our proposed design strategy can be applied to other stove development initiatives in China and other countries.

US ITER Management Plan

International Nuclear Information System (INIS)

1991-12-01

This US ITER Management Plan is the plan for conducting the Engineering Design Activities within the US. The plan applies to all design, analyses, and associated physics and technology research and development (R ampersand D) required to support the program. The plan defines the management considerations associated with these activities. The plan also defines the management controls that the project participants will follow to establish, implement, monitor, and report these activities. The activities are to be conducted by the project in accordance with this plan. The plan will be updated to reflect the then-current management approach required to meet the project objectives. The plan will be reviewed at least annually for possible revision. Section 2 presents the ITER objectives, a brief description of the ITER concept as developed during the Conceptual Design Activities, and comments on the Engineering Design Activities. Section 3 discusses the planned international organization for the Engineering Design Activities, from which the tasks will flow to the US Home Team. Section 4 describes the US ITER management organization and responsibilities during the Engineering Design Activities. Section 5 describes the project management and control to be used to perform the assigned tasks during the Engineering Design Activities. Section 6 presents the references. Several appendices are provided that contain detailed information related to the front material

Accurate characterisation of post moulding shrinkage of polymer parts

DEFF Research Database (Denmark)

Neves, L. C.; De Chiffre, L.; González-Madruga, D.

2015-01-01

The work deals with experimental determination of the shrinkage of polymer parts after injection moulding. A fixture for length measurements on 8 parts at the same time was designed and manufactured in Invar, mounted with 8 electronic gauges, and provided with 3 temperature sensors. The fixture w...

The Iterative Solution to Discrete-Time H∞ Control Problems for Periodic Systems

Directory of Open Access Journals (Sweden)

Ivan G. Ivanov

2016-03-01

Full Text Available This paper addresses the problem of solving discrete-time H ∞ control problems for periodic systems. The approach for solving such a type of equations is well known in the literature. However, the focus of our research is set on the numerical computation of the stabilizing solution. In particular, two effective methods for practical realization of the known iterative processes are described. Furthermore, a new iterative approach is investigated and applied. On the basis of numerical experiments, we compare the presented methods. A major conclusion is that the new iterative approach is faster than rest of the methods and it uses less RAM memory than other methods.

A new subspace based approach to iterative learning control

NARCIS (Netherlands)

Nijsse, G.; Verhaegen, M.; Doelman, N.J.

2001-01-01

This paper1 presents an iterative learning control (ILC) procedure based on an inverse model of the plant under control. Our first contribution is that we formulate the inversion procedure as a Kalman smoothing problem: based on a compact state space model of a possibly non-minimum phase system,

Shrinkages in heavy-sized cast components of nodular cast iron – NDT and fatigue

Directory of Open Access Journals (Sweden)

Bleicher Christoph

2014-06-01

Full Text Available Material defects like shrinkages, dross, pores and chunky graphite are likely to occur in thick-walled castings and are a challenge for the foundries and their customers. These defects are mostly detected with handheld ultrasonic testing (UT or X-ray analysis. Within a research project done at the Fraunhofer Institute for Structural Durability and System Reliability LBF, the fatigue of Dross, shrinkages and chunky graphite in thick-walled cast material GGG-40 was estimated based on X-ray and fatigue tests on bending specimens. High fatigue reductions were received for the different material imperfections. Based on these impressions a further research project was executed at the Fraunhofer LBF to get an estimation of the informational value of UT in relation to fatigue of shrinkages in thick-walled castings of the material EN-GJS-400-18U-LT, EN-GJS-450-18 and EN-GJS-700-2. With the help of X-ray analysis and the UT technique Sampling Phased Array (SPA information about geometry and density were derived for a numerical analysis of shrinkages in thick-walled castings concerning fatigue. The following text summarizes the fatigue results achieved in the two research projects with the help of the X-ray and UT analysis.

OPTIMAL SHRINKAGE ESTIMATION OF MEAN PARAMETERS IN FAMILY OF DISTRIBUTIONS WITH QUADRATIC VARIANCE.

Science.gov (United States)

Xie, Xianchao; Kou, S C; Brown, Lawrence

2016-03-01

This paper discusses the simultaneous inference of mean parameters in a family of distributions with quadratic variance function. We first introduce a class of semi-parametric/parametric shrinkage estimators and establish their asymptotic optimality properties. Two specific cases, the location-scale family and the natural exponential family with quadratic variance function, are then studied in detail. We conduct a comprehensive simulation study to compare the performance of the proposed methods with existing shrinkage estimators. We also apply the method to real data and obtain encouraging results.

Effect of vacuum arc melting/casting parameters on shrinkage cavity/piping of austenitic stainless steel ingot

International Nuclear Information System (INIS)

Kamran, J.; Feroz, M.; Sarwar, M.

2009-01-01

Shrinkage cavity/piping at the end of the solidified ingot of steels is one of the most common casting problem in 316L austenitic stainless steel ingot, when consumable electrode is melted and cast in a water-cooled copper mould by vacuum arc re-melting furnace. In present study an effort has been made to reduce the size of shrinkage cavity/ piping by establishing the optimum value of hot topping process parameters at the end of the melting process. It is concluded that the shrinkage cavity/piping at the top of the solidified ingot can be reduced to minimum by adjusting the process parameters particularly the melting current density. (author)

ITER-FEAT - outline design report. Report by the ITER Director. ITER meeting, Tokyo, January 2000

International Nuclear Information System (INIS)

2001-01-01

It is now possible to define the key elements of ITER-FEAT. This report provides the results, to date, of the joint work of the Special Working Group in the form of an Outline Design Report on the ITER-FEAT design which, subject to the views of ITER Council and of the Parties, will be the focus of further detailed design work and analysis in order to provide to the Parties a complete and fully integrated engineering design within the framework of the ITER EDA extension

Self-Shrinkage Behaviors of Waste Paper Fiber Reinforced Cement Paste considering Its Self-Curing Effect at Early-Ages

Directory of Open Access Journals (Sweden)

Zhengwu Jiang

2016-01-01

Full Text Available The aim of this paper was to study how the early-age self-shrinkage behavior of cement paste is affected by the addition of the waste paper fibers under sealed conditions. Although the primary focus was to determine whether the waste paper fibers are suitable to mitigate self-shrinkage as an internal curing agent under different adding ways, evaluating their strength, pore structure, and hydration properties provided further insight into the self-cured behavior of cement paste. Under the wet mixing condition, the waste paper fibers could mitigate the self-shrinkage of cement paste and, at additions of 0.2% by mass of cement, the waste paper fibers were found to show significant self-shrinkage cracking control while providing some internal curing. In addition, the self-curing efficiency results were analyzed based on the strength and the self-shrinkage behaviors of cement paste. Results indicated that, under a low water cement ratio, an optimal dosage and adding ways of the waste paper fibers could enhance the self-curing efficiency of cement paste.

Initial studies of reflectometer for ITER

International Nuclear Information System (INIS)

Luhmann, N.C. Jr.

1993-12-01

ITER-related activities taking place over the last year were concentrated primarily on the area of advanced reflectometry systems. In particular, we have concentrated on reflectometer systems for density profile and density fluctuation studies on ITER. This interest has led us to spend much of our time investigating the pulsed radar time-of-flight reflectometer approaches (i.e. moderate pulse and ultrashort pulse). Pulsed radar systems offer the ability to make detailed profile measurements using fixed frequency sources, avoiding the need for highly stable sweepable sources as required by the more traditional FM radar systems

The Shrinkage Model And Expert System Of Plastic Lens Formation

Science.gov (United States)

Chang, Rong-Seng

1988-06-01

Shrinkage causes both the appearance & dimension defects of the injected plastic lens. We have built up a model of state equations with the help of finite element analysis program to estimate the volume change (shrinkage and swelling) under the combinations of injection variables such as pressure and temperature etc., then the personal computer expert system has been build up to make that knowledge conveniently available to the user in the model design, process planning, process operation and some other work. The domain knowledge is represented by a R-graph (Relationship-graph) model which states the relationships of variables & equations. This model could be compare with other models in the expert system. If the user has better model to solve the shrinkage problem, the program will evaluate it automatically and a learning file will be trigger by the expert system to teach the user to update their knowledge base and modify the old model by this better model. The Rubin's model and Gilmore's model have been input to the expert system. The conflict has been solved both from the user and the deeper knowledge base. A cube prism and the convex lens examples have been shown in this paper. This program is written by MULISP language in IBM PC-AT. The natural language provides English Explaination of know why and know how and the automatic English translation for the equation rules and the production rules.

Influence of gelatinous fibers on the shrinkage of silver maple

Science.gov (United States)

Donals G. Arganbright; Dwight W. Bensend; Floyd G. Manwiller

1970-01-01

The degree of lean was found to have a significant influence on the logitudinal and transverse shrinkage of three soft maple trees. This may be accounted for by differences in the cell wall layer thickness and fibril angle.

The ITER project technological challenges

CERN Multimedia

CERN. Geneva; Lister, Joseph; Marquina, Miguel A; Todesco, Ezio

2005-01-01

The first lecture reminds us of the ITER challenges, presents hard engineering problems, typically due to mechanical forces and thermal loads and identifies where the physics uncertainties play a significant role in the engineering requirements. The second lecture presents soft engineering problems of measuring the plasma parameters, feedback control of the plasma and handling the physics data flow and slow controls data flow from a large experiment like ITER. The last three lectures focus on superconductors for fusion. The third lecture reviews the design criteria and manufacturing methods for 6 milestone-conductors of large fusion devices (T-7, T-15, Tore Supra, LHD, W-7X, ITER). The evolution of the designer approach and the available technologies are critically discussed. The fourth lecture is devoted to the issue of performance prediction, from a superconducting wire to a large size conductor. The role of scaling laws, self-field, current distribution, voltage-current characteristic and transposition are...

Multicore Performance of Block Algebraic Iterative Reconstruction Methods

DEFF Research Database (Denmark)

Sørensen, Hans Henrik B.; Hansen, Per Christian

2014-01-01

Algebraic iterative methods are routinely used for solving the ill-posed sparse linear systems arising in tomographic image reconstruction. Here we consider the algebraic reconstruction technique (ART) and the simultaneous iterative reconstruction techniques (SIRT), both of which rely on semiconv......Algebraic iterative methods are routinely used for solving the ill-posed sparse linear systems arising in tomographic image reconstruction. Here we consider the algebraic reconstruction technique (ART) and the simultaneous iterative reconstruction techniques (SIRT), both of which rely...... on semiconvergence. Block versions of these methods, based on a partitioning of the linear system, are able to combine the fast semiconvergence of ART with the better multicore properties of SIRT. These block methods separate into two classes: those that, in each iteration, access the blocks in a sequential manner...... a fixed relaxation parameter in each method, namely, the one that leads to the fastest semiconvergence. Computational results show that for multicore computers, the sequential approach is preferable....

Urban shrinkage in Germany and the USA: a comparison of transformation patterns and local strategies.

Science.gov (United States)

Wiechmann, Thorsten; Pallagst, Karina M

2012-01-01

Many American and European cities have to deal with demographic and economic trajectories leading to urban shrinkage. According to official data, 13% of urban regions in the US and 54% of those in the EU have lost population in recent years. However, the extent and spatial distribution of declining populations differ significantly between Europe and the US. In Germany, the situation is driven by falling birth rates and the effects of German reunification. In the US, shrinkage is basically related to long-term industrial transformation. But the challenges of shrinking cities seldom appeared on the agendas of politicians and urban planners until recently. This article provides a critical overview of the development paths and local strategies of four shrinking cities: Schwedt and Dresden in eastern Germany; Youngstown and Pittsburgh in the US. A typology of urban growth and shrinkage, from economic and demographic perspectives, enables four types of city to be differentiated and the differences between the US and eastern Germany to be discussed. The article suggests that a new transatlantic debate on policy and planning strategies for restructuring shrinking cities is needed to overcome the dominant growth orientation that in most cases intensifies the negative consequences of shrinkage.

Evaluation of shrinkage temperature of bovine pericardium tissue for bioprosthetic heart valve application by differential scanning calorimetry and freeze-drying microscopy

Directory of Open Access Journals (Sweden)

Virgilio Tattini Jr

2007-03-01

Full Text Available Bovine pericardium bioprosthesis has become a commonly accepted device for heart valve replacement. Present practice relies on the measurement of shrinkage temperature, observed as a dramatic shortening of tissue length. Several reports in the last decade have utilized differential scanning calorimetry (DSC as an alternative method to determine the shrinkage temperature, which is accompanied by the absorption of heat, giving rise to an endothermic peak over the shrinkage temperature range of biological tissues. Usually, freeze-drying microscope is used to determine collapse temperature during the lyophilization of solutions. On this experiment we used this technique to study the shrinkage event. The aim of this work was to compare the results of shrinkage temperature obtained by DSC with the results obtained by freeze-drying microscopy. The results showed that both techniques provided excellent sensitivity and reproducibility, and gave information on the thermal shrinkage transition via the thermodynamical parameters inherent of each method.

U.S. Contributions to ITER

International Nuclear Information System (INIS)

Sauthoff, Ned R.

2005-01-01

The United States participates in the ITER project and program to enable the study of the science and technology of burning plasmas, a key programmatic element missing from the world fusion program. The 2003 U.S. decision to enter the ITER negotiations followed an extensive series of community and governmental reviews of the benefits, readiness, and approaches to the study of burning plasmas. This paper describes both the technical and the organizational preparations and plans for U.S. participation in the ITER construction activity: in-kind contributions, staff contributions, and cash contributions as well as supporting physics and technology research. Near-term technical activities focus on the completion of R and D and design and mitigation of risks in the areas of the central solenoid magnet, shield/blanket, diagnostics, ion cyclotron system, electron cyclotron system, pellet fueling system, vacuum system, tritium processing system, and conventional systems. Outside the project, the U .S. is engaged in preparations for the test blanket module program. Organizational activities focus on preparations of the project management arrangements to maximize the overall success of the ITER Project; elements include refinement of U.S. directions on the international arrangements, the establishment of the U.S. Domestic Agency, progress along the path of the U.S. Department of Energy's Project Management Order, and overall preparations for commencement of the fabrication of major items of equipment and for provision of staff and cash as specified in the upcoming ITER agreement

Preliminary RAMI analysis of DFLL TBS for ITER

Energy Technology Data Exchange (ETDEWEB)

Wang, Dagui [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); University of Science and Technology of China, Hefei, Anhui, 230031 (China); Yuan, Run [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Wang, Jiaqun, E-mail: jiaqun.wang@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Wang, Fang; Wang, Jin [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China)

2016-11-15

Highlights: • We performed the functional analysis of the DFLL TBS. • We performed a failure mode analysis of the DFLL TBS. • We estimated the reliability and availability of the DFLL TBS. • The ITER RAMI approach was applied to the DFLL TBS for technical risk control in the design phase. - Abstract: ITER is the first fusion machine fully designed to prove the physics and technological basis for next fusion power plants. Among the main technical objectives of ITER is to test and validate design concepts of tritium breeding blankets relevant to the fusion power plants. To achieve this goal, China has proposed the dual functional lithium-lead test blanket module (DFLL TBM) concept design. The DFLL TBM and its associated ancillary system were called DFLL TBS. The DFLL TBS play a key role in next fusion reactor. In order to ensure reliable and available of DFLL TBS, the risk control project of DFLL TBS has been put on the schedule. As the stage of the ITER technical risk control policy, the RAMI (Reliability, Availability, Maintainability, Inspectability) approach was used to control the technical risk of ITER. In this paper, the RAMI approach was performed on the conceptual design of DFLL TBS. A functional breakdown was prepared on DFLL TBS, and the system was divided into 3 main functions and 72 basic functions. Based on the result of functional breakdown of DFLL TBS, the reliability block diagrams were prepared to estimate the reliability and availability of each function under the stipulated operating conditions. The inherent availability of the DFLL TBS expected after implementation of mitigation actions was calculated to be 98.57% over 2 years based on the ITER reliability database. A Failure Modes Effects and Criticality Analysis (FMECA) was performed with criticality charts highlighting the risk level of the different failure modes with regard to their probability of occurrence and their effects on the availability.

Drying shrinkage problems in high-plastic clay soils in Oklahoma.

Science.gov (United States)

2013-08-01

Longitudinal cracking in pavements due to drying shrinkage of high-plastic subgrade soils has been a major : problem in Oklahoma. Annual maintenance to seal and repair these distress problems costs significant amount of : money to the state. The long...

Effects of moisture migration on shrinkage, pore pressure and other concrete properties

International Nuclear Information System (INIS)

Chapman, D.A.; England, G.L.

1977-01-01

This work investigates the uniaxial migration of moisture in long, upright, limestone concrete cylinders, sealed at the base and sides, and open at the top. The design represents a section through a concrete pressure vessel wall. The cylinders are subjected to a sustained temperature difference between their ends, with maximum temperatures between 105 0 C and 200 0 C. Readings of pore pressure, water content and temperature are taken at various positions along the axis of the cylinders. In one cylinder transverse and longitudinal shrinkage readings are also recorded. The results for the cylinders show that moisture migration is away from the hot face of the specimens, causing reduction in both pore pressure and water content values in this region. The moisture migration creates a drying front which moves slowly up the specimens. Evaporation drying takes place from the unsealed end of the specimen. A drying front moves into the concrete and considerable weight loss is recorded as moisture escapes to the atmosphere. The rate of movement of the drying front is slower than that of the hot front and is proportional to the temperature difference between the top of the specimen and the surrounding atmosphere. In the shrinkage specimen, values of transverse and longitudinal shrinkage reflect the water content results. The specimen indicates that shrinkage occurs in a concrete pressure vessel, in the regions where moisture is lost. The restraint of the mass of concrete surrounding these regions sets up a three dimensional state of internal tensile stress. The areas into which the moisture migrates tend to swell, creating an internal stress situation, which is this

ITER council proceedings: 2001

International Nuclear Information System (INIS)

2001-01-01

Continuing the ITER EDA, two further ITER Council Meetings were held since the publication of ITER EDA documentation series no, 20, namely the ITER Council Meeting on 27-28 February 2001 in Toronto, and the ITER Council Meeting on 18-19 July in Vienna. That Meeting was the last one during the ITER EDA. This volume contains records of these Meetings, including: Records of decisions; List of attendees; ITER EDA status report; ITER EDA technical activities report; MAC report and advice; Final report of ITER EDA; and Press release

Drying and radial shrinkage characteristics and changes in color ...

African Journals Online (AJOL)

Drying and radial shrinkage characteristics and changes in color and shape of carrots tissues during air drying were studied. Slices dimensions were obtained by computer vision and the color was quantified by chroma, hue, whitening index and total carotenoids contents. The drying time became shorter of 1 h when ...

Toward Generalization of Iterative Small Molecule Synthesis

Science.gov (United States)

Lehmann, Jonathan W.; Blair, Daniel J.; Burke, Martin D.

2018-01-01

Small molecules have extensive untapped potential to benefit society, but access to this potential is too often restricted by limitations inherent to the customized approach currently used to synthesize this class of chemical matter. In contrast, the “building block approach”, i.e., generalized iterative assembly of interchangeable parts, has now proven to be a highly efficient and flexible way to construct things ranging all the way from skyscrapers to macromolecules to artificial intelligence algorithms. The structural redundancy found in many small molecules suggests that they possess a similar capacity for generalized building block-based construction. It is also encouraging that many customized iterative synthesis methods have been developed that improve access to specific classes of small molecules. There has also been substantial recent progress toward the iterative assembly of many different types of small molecules, including complex natural products, pharmaceuticals, biological probes, and materials, using common building blocks and coupling chemistry. Collectively, these advances suggest that a generalized building block approach for small molecule synthesis may be within reach. PMID:29696152

Polymerization Behavior and Mechanical Properties of High-Viscosity Bulk Fill and Low Shrinkage Resin Composites.

Science.gov (United States)

Shibasaki, S; Takamizawa, T; Nojiri, K; Imai, A; Tsujimoto, A; Endo, H; Suzuki, S; Suda, S; Barkmeier, W W; Latta, M A; Miyazaki, M

The present study determined the mechanical properties and volumetric polymerization shrinkage of different categories of resin composite. Three high viscosity bulk fill resin composites were tested: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent), Filtek Bulk Fill posterior restorative (FB, 3M ESPE), and Sonic Fill (SF, Kerr Corp). Two low-shrinkage resin composites, Kalore (KL, GC Corp) and Filtek LS Posterior (LS, 3M ESPE), were used. Three conventional resin composites, Herculite Ultra (HU, Kerr Corp), Estelite ∑ Quick (EQ, Tokuyama Dental), and Filtek Supreme Ultra (SU, 3M ESPE), were used as comparison materials. Following ISO Specification 4049, six specimens for each resin composite were used to determine flexural strength, elastic modulus, and resilience. Volumetric polymerization shrinkage was determined using a water-filled dilatometer. Data were evaluated using analysis of variance followed by Tukey's honestly significant difference test (α=0.05). The flexural strength of the resin composites ranged from 115.4 to 148.1 MPa, the elastic modulus ranged from 5.6 to 13.4 GPa, and the resilience ranged from 0.70 to 1.0 MJ/m 3 . There were significant differences in flexural properties between the materials but no clear outliers. Volumetric changes as a function of time over a duration of 180 seconds depended on the type of resin composite. However, for all the resin composites, apart from LS, volumetric shrinkage began soon after the start of light irradiation, and a rapid decrease in volume during light irradiation followed by a slower decrease was observed. The low shrinkage resin composites KL and LS showed significantly lower volumetric shrinkage than the other tested materials at the measuring point of 180 seconds. In contrast, the three bulk fill resin composites showed higher volumetric change than the other resin composites. The findings from this study provide clinicians with valuable information regarding the mechanical properties and

Heat treatment trials for ITER toroidal field coils

International Nuclear Information System (INIS)

Matsui, Kunihiro; Hemmi, Tsutomu; Koizumi, Norikiyo; Nakajima, Hideo; Kimura, Satoshi; Nakamoto, Kazunari

2012-01-01

Cable-in-conduit (CIC) conductors using Nb 3 Sn strands are used in ITER toroidal fields (TF) coils. Heat treatment generates thermal strain in CIC conductors because of the difference in thermal expansion between the Nb 3 Sn strands and the stainless-steel jacket. The elongation/shrinkage of the TF conductor may make it impossible to insert a wound TF conductor into the groove of a radial plate. In addition, it is expected that the deformation of the winding due to heat treatment-based release of the residual force in the jacket may also make it impossible to insert the winding in the groove, and that correcting the winding geometry to allow insertion of the winding may influence the superconducting performance of the TF conductor. The authors performed several trials using heat treatment as the part of activities in Phase II of TF coil procurement aiming to resolve the above-mentioned technical issues, and evaluated the elongations of 0.064, 0.074 and 0.072% for the straight and curved conductors and 1/3-scale double-pancake (DP) winding, respectively. It was confirmed that correction if the deformed winding did not influence the superconducting performance of the conductor. (author)

An implicit iterative scheme for solving large systems of linear equations

International Nuclear Information System (INIS)

Barry, J.M.; Pollard, J.P.

1986-12-01

An implicit iterative scheme for the solution of large systems of linear equations arising from neutron diffusion studies is presented. The method is applied to three-dimensional reactor studies and its performance is compared with alternative iterative approaches

A Comparison of Curing Process-Induced Residual Stresses and Cure Shrinkage in Micro-Scale Composite Structures with Different Constitutive Laws

Science.gov (United States)

Li, Dongna; Li, Xudong; Dai, Jianfeng; Xi, Shangbin

2018-02-01

In this paper, three kinds of constitutive laws, elastic, "cure hardening instantaneously linear elastic (CHILE)" and viscoelastic law, are used to predict curing process-induced residual stress for the thermoset polymer composites. A multi-physics coupling finite element analysis (FEA) model implementing the proposed three approaches is established in COMSOL Multiphysics-Version 4.3b. The evolution of thermo-physical properties with temperature and degree of cure (DOC), which improved the accuracy of numerical simulations, and cure shrinkage are taken into account for the three models. Subsequently, these three proposed constitutive models are implemented respectively in a 3D micro-scale composite laminate structure. Compared the differences between these three numerical results, it indicates that big error in residual stress and cure shrinkage generates by elastic model, but the results calculated by the modified CHILE model are in excellent agreement with those estimated by the viscoelastic model.

Self-healing of drying shrinkage cracks in cement-based materials incorporating reactive MgO

Science.gov (United States)

Qureshi, T. S.; Al-Tabbaa, A.

2016-08-01

Excessive drying shrinkage is one of the major issues of concern for longevity and reduced strength performance of concrete structures. It can cause the formation of cracks in the concrete. This research aims to improve the autogenous self-healing capacity of traditional Portland cement (PC) systems, adding expansive minerals such as reactive magnesium oxide (MgO) in terms of drying shrinkage crack healing. Two different reactive grades (high ‘N50’and moderately high ‘92-200’) of MgO were added with PC. Cracks were induced in the samples with restraining end prisms through natural drying shrinkage over 28 days after casting. Samples were then cured under water for 28 and 56 days, and self-healing capacity was investigated in terms of mechanical strength recovery, crack sealing efficiency and improvement in durability. Finally, microstructures of the healing materials were investigated using FT-IR, XRD, and SEM-EDX. Overall N50 mixes show higher expansion and drying shrinkage compared to 92-200 mixes. Autogenous self-healing performance of the MgO containing samples were much higher compared to control (only PC) mixes. Cracks up to 500 μm were sealed in most MgO containing samples after 28 days. In the microstructural investigations, highly expansive Mg-rich hydro-carbonate bridges were found along with traditional calcium-based, self-healing compounds (calcite, portlandite, calcium silicate hydrates and ettringite).

Drying and Radial Shrinkage Characteristics and Changes in Color ...

African Journals Online (AJOL)

nahimana

2011-08-12

Aug 12, 2011 ... A pre-test experiment was carried out following the. Thompson ... energy saving potential and the ability to control drying temperature and air humidity. ..... structural collapse by shrinkage, case hardening, etc. From the slopes of .... Thus, the Nahimana et al. model is proposed as a new model predicting with ...

Shrinkage Porosity Criterion and Its Application to A 5.5 Ton Steel Ingot

Directory of Open Access Journals (Sweden)

Zhang C.

2016-06-01

Full Text Available In order to predict the distribution of shrinkage porosity in steel ingot efficiently and accurately, a criterion R√L and a method to obtain its threshold value were proposed. The criterion R√L was derived based on the solidification characteristics of steel ingot and pressure gradient in the mushy zone, in which the physical properties, the thermal parameters, the structure of the mushy zone and the secondary dendrite arm spacing were all taken into consideration. The threshold value of the criterion R√L was obtained with combination of numerical simulation of ingot solidification and total solidification shrinkage rate. Prediction of the shrinkage porosity in a 5.5 ton ingot of 2Cr13 steel with criterion R√L>0.21 m · °C1/2 · s−3/2 agreed well with the results of experimental sectioning. Based on this criterion, optimization of the ingot was carried out by decreasing the height-to-diameter ratio and increasing the taper, which successfully eliminated the centreline porosity and further proved the applicability of this criterion.

The correlation between aldehyde dehydrogenase-1A1 level and tumor shrinkage after preoperative chemoradiation in locally advanced rectal cancer

Directory of Open Access Journals (Sweden)

Rhandyka Rafli

2015-12-01

Full Text Available This study was performed to determine the correlation between aldehyde dehydrogenase-1A1 (ALDH1A1 level and tumor shrinkage after chemoradiation in locally advanced rectal cancer. This is a retrospective study of 14 locally advanced rectal cancer patients with long course neoadjuvant chemoradiation. ALDH1A1 level was measured using ELISA from paraffin embedded tissue. Tumor shrinkage was measured from computed tomography (CT scan or magnetic resonance imaging (MRI based on Response Evaluation Criteria in Solid Tumor v1.1 (RECIST v1.1. The mean of ALDH1A1 level was 9.014 ± 3.3 pg/mL and the mean of tumor shrinkage was 7.89 ± 35.7%. Partial response proportion was 28.6%, stable disease proportion was 50% and progressive disease proportion was 21.4%. There was a significant strong negative correlation (r = –0.890, plt; 0.001 between ALDH1A1 and tumor shrinkage. In conclusion, tumor shrinkage in locally advanced rectal cancer after preoperative chemoradiation was influenced by ALDH1A1 level. Higher level of ALDH1A1 suggests decreased tumor shrinkage after preoperative chemoradiation.

ITER instrumentation and control-Status and plans

International Nuclear Information System (INIS)

Wallander, Anders; Abadie, Lana; Dave, Haresh; Di Maio, Franck; Gulati, Hitesh Kumar; Hansalia, Chandresh; Joonekindt, Didier; Journeaux, Jean-Yves; Klotz, Wolf-Dieter; Mahajan, Kirti; Makijarvi, Petri; Scibile, Luigi; Stepanov, Denis; Utzel, Nadine; Yonekawa, Izuru

2010-01-01

The ITER instrumentation and control (I and C) system is the term encompassing all hardware and software required to operate ITER. It has two levels of hierarchy: the central I and C systems and the plant systems I and C. The central I and C systems comprise CODAC (Control, Data Access and Communication), the central interlock system (CIS) and the central safety systems (CSS). The central I and C systems are 'in-fund', i.e. procured by ITER Organization (IO), while plant systems I and C are 'in-kind', i.e. procured by the seven ITER domestic agencies. This procurement model, together with the current estimate of 161 plant systems I and C, poses a major challenge for the realization and integration of the ITER I and C system. To address this challenge a main strategic focus of the CODAC group, formed in 2008, has been to establish good relations with the domestic agencies. By distributing the required R and D tasks and contracts fairly between the domestic agencies we build collaborations for the future at the same time as technical work proceed. The primary goal of ITER I and C system is to provide a fully integrated and automated control system for ITER. Standardization of plant systems I and C is of primary importance and has been the highest priority task during the last year. The target of associated R and D activities is to survey, benchmark and prototype main stream technologies, in order to choose the best and most widely used technology standards for plant systems I and C. In this paper we elaborate on our approach, both from a technical and a non-technical perspective, explain technology evaluation and decisions and finally present the way forward to ensure ITER I and C system will contribute and be instrumental in making ITER a success.

Post-convergence automatic differentiation of iterative schemes

International Nuclear Information System (INIS)

Azmy, Y.Y.

1997-01-01

A new approach for performing automatic differentiation (AD) of computer codes that embody an iterative procedure, based on differentiating a single additional iteration upon achieving convergence, is described and implemented. This post-convergence automatic differentiation (PAD) technique results in better accuracy of the computed derivatives, as it eliminates part of the derivatives convergence error, and a large reduction in execution time, especially when many iterations are required to achieve convergence. In addition, it provides a way to compute derivatives of the converged solution without having to repeat the entire iterative process every time new parameters are considered. These advantages are demonstrated and the PAD technique is validated via a set of three linear and nonlinear codes used to solve neutron transport and fluid flow problems. The PAD technique reduces the execution time over direct AD by a factor of up to 30 and improves the accuracy of the derivatives by up to two orders of magnitude. The PAD technique's biggest disadvantage lies in the necessity to compute the iterative map's Jacobian, which for large problems can be prohibitive. Methods are discussed to alleviate this difficulty

iterClust: a statistical framework for iterative clustering analysis.

Science.gov (United States)

Ding, Hongxu; Wang, Wanxin; Califano, Andrea

2018-03-22

In a scenario where populations A, B1 and B2 (subpopulations of B) exist, pronounced differences between A and B may mask subtle differences between B1 and B2. Here we present iterClust, an iterative clustering framework, which can separate more pronounced differences (e.g. A and B) in starting iterations, followed by relatively subtle differences (e.g. B1 and B2), providing a comprehensive clustering trajectory. iterClust is implemented as a Bioconductor R package. andrea.califano@columbia.edu, hd2326@columbia.edu. Supplementary information is available at Bioinformatics online.

Multi-Level iterative methods in computational plasma physics

International Nuclear Information System (INIS)

Knoll, D.A.; Barnes, D.C.; Brackbill, J.U.; Chacon, L.; Lapenta, G.

1999-01-01

Plasma physics phenomena occur on a wide range of spatial scales and on a wide range of time scales. When attempting to model plasma physics problems numerically the authors are inevitably faced with the need for both fine spatial resolution (fine grids) and implicit time integration methods. Fine grids can tax the efficiency of iterative methods and large time steps can challenge the robustness of iterative methods. To meet these challenges they are developing a hybrid approach where multigrid methods are used as preconditioners to Krylov subspace based iterative methods such as conjugate gradients or GMRES. For nonlinear problems they apply multigrid preconditioning to a matrix-few Newton-GMRES method. Results are presented for application of these multilevel iterative methods to the field solves in implicit moment method PIC, multidimensional nonlinear Fokker-Planck problems, and their initial efforts in particle MHD

D-Iteration: diffusion approach for solving PageRank

OpenAIRE

Hong, Dohy; Huynh, The Dang; Mathieu, Fabien

2015-01-01

In this paper we present a new method that can accelerate the computation of the PageRank importance vector. Our method, called D-Iteration (DI), is based on the decomposition of the matrix-vector product that can be seen as a fluid diffusion model and is potentially adapted to asynchronous implementation. We give theoretical results about the convergence of our algorithm and we show through experimentations on a real Web graph that DI can improve the computation efficiency compared to other ...

Non-uniform shrinkage of multiple-walled carbon nanotubes under in situ electron beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Li, Lunxiong [South China Normal University, Brain Science Institute, Guangzhou (China); Xiamen University, China-Australia Joint Laboratory for Functional Nanomaterials and Physics Department, Xiamen (China); Su, Jiangbin [Xiamen University, China-Australia Joint Laboratory for Functional Nanomaterials and Physics Department, Xiamen (China); Chang Zhou University, School of Mathematics and Physics, Changzhou (China); Zhu, Xianfang [Xiamen University, China-Australia Joint Laboratory for Functional Nanomaterials and Physics Department, Xiamen (China)

2016-10-15

Instability of multiple-walled carbon nanotubes (MWCNTs) was investigated by in situ transmission electron microscopy at room temperature. Specially, the non-uniform shrinkage of tubes was found: The pristine MWCNT shrank preferentially in its axial direction from the most curved free cap end of the tube, but the shrinkage of the tube diameter was offset by the axial shrinkage: For the complex MWCNT, the two inner MWCNTs also preferentially axially shrank from their most curved cap ends and separated from each other. However, for the effect of the radial pressure from the out walls which enveloped the two inner tubes and the tube amorphization, the two inner tubes were extruded to come close to each other and finally touched again. The new ''evaporation'' and ''diffusion'' mechanisms of carbon atoms as driven by the nano-curvature of CNT and the electron beam-induced athermal activation were suggested to explain the above phenomena. (orig.)

Laplace transform overcoming principle drawbacks in application of the variational iteration method to fractional heat equations

Directory of Open Access Journals (Sweden)

Wu Guo-Cheng

2012-01-01

Full Text Available This note presents a Laplace transform approach in the determination of the Lagrange multiplier when the variational iteration method is applied to time fractional heat diffusion equation. The presented approach is more straightforward and allows some simplification in application of the variational iteration method to fractional differential equations, thus improving the convergence of the successive iterations.

Improving the iterative Linear Interaction Energy approach using automated recognition of configurational transitions.

Science.gov (United States)

Vosmeer, C Ruben; Kooi, Derk P; Capoferri, Luigi; Terpstra, Margreet M; Vermeulen, Nico P E; Geerke, Daan P

2016-01-01

Recently an iterative method was proposed to enhance the accuracy and efficiency of ligand-protein binding affinity prediction through linear interaction energy (LIE) theory. For ligand binding to flexible Cytochrome P450s (CYPs), this method was shown to decrease the root-mean-square error and standard deviation of error prediction by combining interaction energies of simulations starting from different conformations. Thereby, different parts of protein-ligand conformational space are sampled in parallel simulations. The iterative LIE framework relies on the assumption that separate simulations explore different local parts of phase space, and do not show transitions to other parts of configurational space that are already covered in parallel simulations. In this work, a method is proposed to (automatically) detect such transitions during the simulations that are performed to construct LIE models and to predict binding affinities. Using noise-canceling techniques and splines to fit time series of the raw data for the interaction energies, transitions during simulation between different parts of phase space are identified. Boolean selection criteria are then applied to determine which parts of the interaction energy trajectories are to be used as input for the LIE calculations. Here we show that this filtering approach benefits the predictive quality of our previous CYP 2D6-aryloxypropanolamine LIE model. In addition, an analysis is performed of the gain in computational efficiency that can be obtained from monitoring simulations using the proposed filtering method and by prematurely terminating simulations accordingly.

Early age volume changes in concrete due to chemical shrinkage of cement paste

Directory of Open Access Journals (Sweden)

Ebensperger, L.

1991-12-01

Full Text Available Unrestrained early age volume changes due to chemical shrinkage in cement pastes, mortars and concretes have been determined. The measurements were performed on sealed and unsealed samples which were stored under water. The chemical shrinkage of unsealed specimens represents the amount of absorbed water due to the chemical reaction of the cement It depends only on the cement content of the sample and does not lead to changes of the external dimensions. However the chemical shrinkage of sealed specimens is connected with a real volume change due to self-desiccation and the effect of internal pressures. The shrinkage depends in this case on the restraining effect of coarse aggregates as well as the cement content. The chemical shrinkage measured on sealed concretes was much higher than the one expected to ocurr on concretes, because normally an equalization of pressure takes place to some extent in the interior of the concrete. The use of expansive additives showed that they may compensate the chemical shrinkage, but its dosage is very sensitive and should be defined exactly for each case particularly.

Se han determinado los cambios volumétricos que ocurren en pastas de cemento, morteros y hormigones a edad temprana debido al efecto de la retracción química. Las mediciones se realizaron en probetas selladas y no selladas sumergidas bajo agua. La retracción química en probetas no selladas representa la cantidad de agua absorbida debido a la reacción química del cemento. Depende solamente del contenido de cemento de la probeta y no produce ningún cambio en las dimensiones de la probeta. Por el contrario, la retracción química en probetas selladas está relacionada con un cambio volumétrico real debido al efecto de la autodesecación y presiones internas. La retracción en este caso depende tanto de la restricción que imponen los áridos, como del contenido de cemento. La retracción química medida en hormigones sellados

First time observation of local current shrinkage during the MARFE behavior on the J-TEXT tokamak

Science.gov (United States)

Shi, Peng; Zhuang, G.; Gentle, K.; Hu, Qiming; Chen, Jie; Li, Qiang; Liu, Yang; Gao, Li; Zhang, Xiaolong; Liu, Hai; Chen, Zhipeng; Zhu, Lizhi; Li, Fuming; Zhou, Yinan; Zeng, Zhong; Liu, Linzi; He, Jiyang

2017-11-01

Multifaceted asymmetric radiation as well as strong poloidal asymmetry of the electron density from the edge, dubbed as ‘MARFE’, has been observed in high electron density Ohmically heated plasmas on J-TEXT tokamak. Equilibrium reconstruction based on the measured data from the 17-channel FIR polarimeter-interferometer indicates that an asymmetric plasma current density distribution forms at the edge region and the plasma current shrinkage locates at the MARFE affected region. Furthermore, associated with the localized plasma current shrinkage, a locked mode MHD activity is excited, which then terminate the discharge with a major disruption. Localized plasma current shrinkage at the MARFE region is considered to be the direct cause for the density limit disruptions, and the proposed interpretation is consistent with the experimental observations.

Shrinkage Simulation of Holographic Grating Using Diffusion Model in PQ-PMMA Photopolymer

Directory of Open Access Journals (Sweden)

Wei Zepeng

2015-01-01

Full Text Available An extended model based on nonlocal polymerization-driven diffusion model is derived by introducing shrinkage process for describing photopolymerized dynamics in PQ-PMMA photopolymer. The kinetic parameters, polymerization rate and diffusion rate are experimentally determined to provide quantitative simulation. The numerical results show that the fringes at edge of grating are firstly shifted and consequently, it leads to a contrast reduction of holograms. Finally, theoretical results are experimentally checked by temporal evolution of diffraction efficiency, and the shrinkage coefficient 0.5% is approximately achieved under incident intensity 25.3mw/cm2. This work can enhance the applicability of diffusion model and contribute to the reasonable description of the grating formation in the photopolymer.

Thoracoscopic CO laser coagulation shrinkage of blebs in treatment of spontaneous pneumothorax

Science.gov (United States)

Sensaki, Koji; Arai, Tsunenori; Kikuchi, Keiichi; Takagi, Keigo; Tanaka, Susumu; Kikuchi, Makoto

1992-06-01

Spontaneous pneumothorax is a common disease in young people. Operative intervention has been done in most of the recurrent cases. Recently thoracoscopic treatment has been tested as a less invasive treatment modarity. We adopted carbon monoxide (CO) laser for thoracoscopic treatment of recurrent spontaneous pneumothorax. CO laser (wavelength; 5.4 micrometers ) could be delivered by chalcogenide glass (As - S) covered with a teflon sheath and ZnSe fiber tip. The sterilized flexible bronchoscope was inserted through the thoracoscopic outer sheath under local anesthesia. Shrinkage of blebs was obtained by non-contact method of CO laser irradiation. Laser power at the tip was 2.5 - 5 W and irradiation duration was 0.5 s each. Excellent shrinkage of bleb and bulla could be obtained by CO laser without perforation complication. Advantages of CO laser as a thoracoscopic treatment were: (1) capability of fiber delivery (flexible thoracoscopy was easy to operate and clear to visualize the blebs which were frequently found at the apical portion of the lung, and (2) shallow extinction length (good shrinkage of blebs, low risk of perforation, and thin layer of carbonization). In conclusion, our new technique of thoracoscopic CO laser irradiation was found to be a safe and effective treatment of spontaneous pneumothorax.

ITER Safety and Licensing

International Nuclear Information System (INIS)

Girard, J-.P; Taylor, N.; Garin, P.; Uzan-Elbez, J.; GULDEN, W.; Rodriguez-Rodrigo, L.

2006-01-01

The site for the construction of ITER has been chosen in June 2005. The facility will be implemented in Europe, south of France close to Marseille. The generic safety scheme is now under revision to adapt the design to the host country regulation. Even though ITER will be an international organization, it will have to comply with the French requirements in the fields of public and occupational health and safety, nuclear safety, radiation protection, licensing, nuclear substances and environmental protection. The organization of the central team together with its partners organized in domestic agencies for the in-kind procurement of components is a key issue for the success of the experimentation. ITER is the first facility that will achieve sustained nuclear fusion. It is both important for the experimental one-of-a-kind device, ITER itself, and for the future of fusion power plants to well understand the key safety issues of this potential new source of energy production. The main safety concern is confinement of the tritium, activated dust in the vacuum vessel and activated corrosion products in the coolant of the plasma-facing components. This is achieved in the design through multiple confinement barriers to implement the defence in depth approach. It will be demonstrated in documents submitted to the French regulator that these barriers maintain their function in all postulated incident and accident conditions. The licensing process started by examination of the safety options. This step has been performed by Europe during the candidature phase in 2002. In parallel to the final design, and taking into account the local regulations, the Preliminary Safety Report (RPrS) will be drafted with support of the European partner and others in the framework of ITER Task Agreements. Together with the license application, the RPrS will be forwarded to the regulatory bodies, which will launch public hearings and a safety review. Both processes must succeed in order to

Iterative Authoring Using Story Generation Feedback: Debugging or Co-creation?

Science.gov (United States)

Swartjes, Ivo; Theune, Mariët

We explore the role that story generation feedback may play within the creative process of interactive story authoring. While such feedback is often used as 'debugging' information, we explore here a 'co-creation' view, in which the outcome of the story generator influences authorial intent. We illustrate an iterative authoring approach in which each iteration consists of idea generation, implementation and simulation. We find that the tension between authorial intent and the partially uncontrollable story generation outcome may be relieved by taking such a co-creation approach.

An Iterative and Incremental Approach for E-Learning Ontology Engineering

Directory of Open Access Journals (Sweden)

Sudath Rohitha Heiyanthuduwage

2009-03-01

Full Text Available Abstract - There is a boost in the interest on ontology with the developments in Semantic Web technologies. Ontologies play a vital role in semantic web. Even though there is lot of work done on ontology, still a standard framework for ontology engineering has not been defined. Even though current ontology engineering methodologies are available they need improvements. The effort of our work is to integrate various methods, techniques, tools and etc to different stages of proposed ontology engineering life cycle to create a comprehensive framework for ontology engineering. Current methodologies discuss ontology engineering stages and collaborative environments with user collaboration. However, discussion on increasing effectiveness and correct inference has been given less attention. More over, these methodologies provide little discussion on usability of domain ontologies. We consider these aspects as more important in our work. Also, ontology engineering has been done for various domains and for various purposes. Our effort is to propose an iterative and incremental approach for ontology engineering especially for e-learning domain with the intention of achieving a higher usability and effectiveness of e-learning systems. This paper introduces different aspects of the proposed ontology engineering framework and evaluation of it.

ITER council proceedings: 2000

International Nuclear Information System (INIS)

2001-01-01

No ITER Council Meetings were held during 2000. However, two ITER EDA Meetings were held, one in Tokyo, January 19-20, and one in Moscow, June 29-30. The parties participating in these meetings were those that partake in the extended ITER EDA, namely the EU, the Russian Federation, and Japan. This document contains, a/o, the records of these meetings, the list of attendees, the agenda, the ITER EDA Status Reports issued during these meetings, the TAC (Technical Advisory Committee) reports and recommendations, the MAC Reports and Advice (also for the July 1999 Meeting), the ITER-FEAT Outline Design Report, the TAC Reports and Recommendations both meetings), Site requirements and Site Design Assumptions, the Tentative Sequence of technical Activities 2000-2001, Report of the ITER SWG-P2 on Joint Implementation of ITER, EU/ITER Canada Proposal for New ITER Identification

Creep and shrinkage of Mo(Ni)

International Nuclear Information System (INIS)

Kaysser, W.A.; Hofmann-Amtenbrink, M.; Petzow, G.

1984-01-01

To avoid some of the errors inherent in a quantitative interpretation of shrinkage of powder compacts as Mo-Ni, other experiments were looked for, where the influence of Ni on the material transport properties of Mo could be measured semi-quantitatively during heating up to temperature and subsequent isothermal annealing. The bending of thin Mo foils under small loads was found to be an experimental arrangement, where variations in stress, in Ni-concentration and in intrinsic material properties could be realized. The results of these creep experiments will be compared in a qualitative sense with sintering experiments in Mo-Ni done under similar conditions as the creep experiments

Iterative learning control an optimization paradigm

CERN Document Server

Owens, David H

2016-01-01

This book develops a coherent theoretical approach to algorithm design for iterative learning control based on the use of optimization concepts. Concentrating initially on linear, discrete-time systems, the author gives the reader access to theories based on either signal or parameter optimization. Although the two approaches are shown to be related in a formal mathematical sense, the text presents them separately because their relevant algorithm design issues are distinct and give rise to different performance capabilities. Together with algorithm design, the text demonstrates that there are new algorithms that are capable of incorporating input and output constraints, enable the algorithm to reconfigure systematically in order to meet the requirements of different reference signals and also to support new algorithms for local convergence of nonlinear iterative control. Simulation and application studies are used to illustrate algorithm properties and performance in systems like gantry robots and other elect...

Demonstration of ITER operational scenarios on DIII-D

International Nuclear Information System (INIS)

Doyle, E.J.; DeBoo, J.C.; Ferron, J.R.; Jackson, G.L.; Luce, T.C.; Osborne, T.H.; Politzer, P.A.; Groebner, R.J.; Hyatt, A.W.; La Haye, R.J.; Petrie, T.W.; Petty, C.C.; Murakami, M.; Park, J.-M.; Reimerdes, H.; Budny, R.V.; Casper, T.A.; Holcomb, C.T.; Challis, C.D.; McKee, G.R.

2010-01-01

The DIII-D programme has recently initiated an effort to provide suitably scaled experimental evaluations of four primary ITER operational scenarios. New and unique features of this work are that the plasmas incorporate essential features of the ITER scenarios and anticipated operating characteristics; e.g. the plasma cross-section, aspect ratio and value of I/aB of the DIII-D discharges match the ITER design, with size reduced by a factor of 3.7. Key aspects of all four scenarios, such as target values for β N and H 98 , have been replicated successfully on DIII-D, providing an improved and unified physics basis for transport and stability modelling, as well as for performance extrapolation to ITER. In all four scenarios, normalized performance equals or closely approaches that required to realize the physics and technology goals of ITER, and projections of the DIII-D discharges are consistent with ITER achieving its goals of ≥400 MW of fusion power production and Q ≥ 10. These studies also address many of the key physics issues related to the ITER design, including the L-H transition power threshold, the size of edge localized modes, pedestal parameter scaling, the impact of tearing modes on confinement and disruptivity, beta limits and the required capabilities of the plasma control system. An example of direct influence on the ITER design from this work is a modification of the physics requirements for the poloidal field coil set at 15 MA, based on observations that the inductance in the baseline scenario case evolves to a value that lies outside the original ITER specification.

Demonstration of ITER Operational Scenarios on DIII-D

International Nuclear Information System (INIS)

Doyle, E.J.; Budny, R.V.; DeBoo, J.C.; Ferron, J.R.; Jackson, G.L.; Luce, T.C.; Murakami, M.; Osborne, T.H.; Park, J.; Politzer, P.A.; Reimerdes, H.; Casper, T.A.; Challis, C.D.; Groebner, R.J.; Holcomb, C.T.; Hyatt, A.W.; La Haye, R.J.; McKee, G.R.; Petrie, T.W.; Petty, C.C.; Rhodes, T.L.; Shafer, M.W.; Snyder, P.B.; Strait, E.J; Wade, M.R.; Wang, G.; West, W.P.; Zeng, L.

2008-01-01

The DIII-D program has recently initiated an effort to provide suitably scaled experimental evaluations of four primary ITER operational scenarios. New and unique features of this work are that the plasmas incorporate essential features of the ITER scenarios and anticipated operating characteristics; e.g., the plasma cross-section, aspect ratio and value of I/aB of the DIII-D discharges match the ITER design, with size reduced by a factor of 3.7. Key aspects of all four scenarios, such as target values for β N and H 98 , have been replicated successfully on DIII-D, providing an improved and unified physics basis for transport and stability modeling, as well as for performance extrapolation to ITER. In all four scenarios normalized performance equals or closely approaches that required to realize the physics and technology goals of ITER, and projections of the DIII-D discharges are consistent with ITER achieving its goals of (ge) 400 MW of fusion power production and Q (ge) 10. These studies also address many of the key physics issues related to the ITER design, including the L-H transition power threshold, the size of ELMs, pedestal parameter scaling, the impact of tearing modes on confinement and disruptivity, beta limits and the required capabilities of the plasma control system. An example of direct influence on the ITER design from this work is a modification of the specified operating range in internal inductance at 15 MA for the poloidal field coil set, based on observations that the measured inductance in the baseline scenario case lay outside the original ITER specification

Perl Modules for Constructing Iterators

Science.gov (United States)

Tilmes, Curt

2009-01-01

The Iterator Perl Module provides a general-purpose framework for constructing iterator objects within Perl, and a standard API for interacting with those objects. Iterators are an object-oriented design pattern where a description of a series of values is used in a constructor. Subsequent queries can request values in that series. These Perl modules build on the standard Iterator framework and provide iterators for some other types of values. Iterator::DateTime constructs iterators from DateTime objects or Date::Parse descriptions and ICal/RFC 2445 style re-currence descriptions. It supports a variety of input parameters, including a start to the sequence, an end to the sequence, an Ical/RFC 2445 recurrence describing the frequency of the values in the series, and a format description that can refine the presentation manner of the DateTime. Iterator::String constructs iterators from string representations. This module is useful in contexts where the API consists of supplying a string and getting back an iterator where the specific iteration desired is opaque to the caller. It is of particular value to the Iterator::Hash module which provides nested iterations. Iterator::Hash constructs iterators from Perl hashes that can include multiple iterators. The constructed iterators will return all the permutations of the iterations of the hash by nested iteration of embedded iterators. A hash simply includes a set of keys mapped to values. It is a very common data structure used throughout Perl programming. The Iterator:: Hash module allows a hash to include strings defining iterators (parsed and dispatched with Iterator::String) that are used to construct an overall series of hash values.

A comprehensive iterative approach is highly effective in diagnosing individuals who are exome negative.

Science.gov (United States)

Shashi, Vandana; Schoch, Kelly; Spillmann, Rebecca; Cope, Heidi; Tan, Queenie K-G; Walley, Nicole; Pena, Loren; McConkie-Rosell, Allyn; Jiang, Yong-Hui; Stong, Nicholas; Need, Anna C; Goldstein, David B

2018-06-15

Sixty to seventy-five percent of individuals with rare and undiagnosed phenotypes remain undiagnosed after exome sequencing (ES). With standard ES reanalysis resolving 10-15% of the ES negatives, further approaches are necessary to maximize diagnoses in these individuals. In 38 ES negative patients an individualized genomic-phenotypic approach was employed utilizing (1) phenotyping; (2) reanalyses of FASTQ files, with innovative bioinformatics; (3) targeted molecular testing; (4) genome sequencing (GS); and (5) conferring of clinical diagnoses when pathognomonic clinical findings occurred. Certain and highly likely diagnoses were made in 18/38 (47%) individuals, including identifying two new developmental disorders. The majority of diagnoses (>70%) were due to our bioinformatics, phenotyping, and targeted testing identifying variants that were undetected or not prioritized on prior ES. GS diagnosed 3/18 individuals with structural variants not amenable to ES. Additionally, tentative diagnoses were made in 3 (8%), and in 5 individuals (13%) candidate genes were identified. Overall, diagnoses/potential leads were identified in 26/38 (68%). Our comprehensive approach to ES negatives maximizes the ES and clinical data for both diagnoses and candidate gene identification, without GS in the majority. This iterative approach is cost-effective and is pertinent to the current conundrum of ES negatives.

Iterated Process Analysis over Lattice-Valued Regular Expressions

DEFF Research Database (Denmark)

Midtgaard, Jan; Nielson, Flemming; Nielson, Hanne Riis

2016-01-01

We present an iterated approach to statically analyze programs of two processes communicating by message passing. Our analysis operates over a domain of lattice-valued regular expressions, and computes increasingly better approximations of each process's communication behavior. Overall the work e...... extends traditional semantics-based program analysis techniques to automatically reason about message passing in a manner that can simultaneously analyze both values of variables as well as message order, message content, and their interdependencies.......We present an iterated approach to statically analyze programs of two processes communicating by message passing. Our analysis operates over a domain of lattice-valued regular expressions, and computes increasingly better approximations of each process's communication behavior. Overall the work...

ITER overview

International Nuclear Information System (INIS)

Shimomura, Y.; Aymar, R.; Chuyanov, V.; Huguet, M.; Parker, R.R.

2001-01-01

This report summarizes technical works of six years done by the ITER Joint Central Team and Home Teams under terms of Agreement of the ITER Engineering Design Activities. The major products are as follows: complete and detailed engineering design with supporting assessments, industrial-based cost estimates and schedule, non-site specific comprehensive safety and environmental assessment, and technology R and D to validate and qualify design including proof of technologies and industrial manufacture and testing of full size or scalable models of key components. The ITER design is at an advanced stage of maturity and contains sufficient technical information for a construction decision. The operation of ITER will demonstrate the availability of a new energy source, fusion. (author)

ITER Overview

International Nuclear Information System (INIS)

Shimomura, Y.; Aymar, R.; Chuyanov, V.; Huguet, M.; Parker, R.

1999-01-01

This report summarizes technical works of six years done by the ITER Joint Central Team and Home Teams under terms of Agreement of the ITER Engineering Design Activities. The major products are as follows: complete and detailed engineering design with supporting assessments, industrial-based cost estimates and schedule, non-site specific comprehensive safety and environmental assessment, and technology R and D to validate and qualify design including proof of technologies and industrial manufacture and testing of full size or scalable models of key components. The ITER design is at an advanced stage of maturity and contains sufficient technical information for a construction decision. The operation of ITER will demonstrate the availability of a new energy source, fusion. (author)

ITER Council proceedings: 1993

International Nuclear Information System (INIS)

1994-01-01

Records of the third ITER Council Meeting (IC-3), held on 21-22 April 1993, in Tokyo, Japan, and the fourth ITER Council Meeting (IC-4) held on 29 September - 1 October 1993 in San Diego, USA, are presented, giving essential information on the evolution of the ITER Engineering Design Activities (EDA), such as the text of the draft of Protocol 2 further elaborated in ''ITER EDA Agreement and Protocol 2'' (ITER EDA Documentation Series No. 5), recommendations on future work programmes: a description of technology R and D tasks; the establishment of a trust fund for the ITER EDA activities; arrangements for Visiting Home Team Personnel; the general framework for the involvement of other countries in the ITER EDA; conditions for the involvement of Canada in the Euratom Contribution to the ITER EDA; and other attachments as parts of the Records of Decision of the aforementioned ITER Council Meetings

ITER council proceedings: 1993

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-31

Records of the third ITER Council Meeting (IC-3), held on 21-22 April 1993, in Tokyo, Japan, and the fourth ITER Council Meeting (IC-4) held on 29 September - 1 October 1993 in San Diego, USA, are presented, giving essential information on the evolution of the ITER Engineering Design Activities (EDA), such as the text of the draft of Protocol 2 further elaborated in ``ITER EDA Agreement and Protocol 2`` (ITER EDA Documentation Series No. 5), recommendations on future work programmes: a description of technology R and D tastes; the establishment of a trust fund for the ITER EDA activities; arrangements for Visiting Home Team Personnel; the general framework for the involvement of other countries in the ITER EDA; conditions for the involvement of Canada in the Euratom Contribution to the ITER EDA; and other attachments as parts of the Records of Decision of the aforementioned ITER Council Meetings.

Reducing Shrinkage in Canned and Frozen Mushrooms

OpenAIRE

Gormley, T. R. (Thomas Ronan); Walshe, P.E.

1982-01-01

The process involving a preliminary soaking of the mushrooms in water for 20 min followed by a chill storage period followed by a further water soak for 2 hr, and known as the 3S process, gave a considerable reduction in total shrinkage in both brown and white strain canned mushrooms compared with the control samples. Water uptake by the mushrooms in the 3S process was greatest when the soaking water temperature was between 20 and 30°C and had a pH of 8. Citric acid in the blanch water enhanc...

Fast generation of computer-generated holograms using wavelet shrinkage.

Science.gov (United States)

Shimobaba, Tomoyoshi; Ito, Tomoyoshi

2017-01-09

Computer-generated holograms (CGHs) are generated by superimposing complex amplitudes emitted from a number of object points. However, this superposition process remains very time-consuming even when using the latest computers. We propose a fast calculation algorithm for CGHs that uses a wavelet shrinkage method, eliminating small wavelet coefficient values to express approximated complex amplitudes using only a few representative wavelet coefficients.

Iterated random walks with shape prior

DEFF Research Database (Denmark)

Pujadas, Esmeralda Ruiz; Kjer, Hans Martin; Piella, Gemma

2016-01-01

the parametric probability density function. Then, random walks is performed iteratively aligning the prior with the current segmentation in every iteration. We tested the proposed approach with natural and medical images and compared it with the latest techniques with random walks and shape priors......We propose a new framework for image segmentation using random walks where a distance shape prior is combined with a region term. The shape prior is weighted by a confidence map to reduce the influence of the prior in high gradient areas and the region term is computed with k-means to estimate....... The experiments suggest that this method gives promising results for medical and natural images....

Modelling of shrinkage cavity defects during the wheel and belt casting process

International Nuclear Information System (INIS)

Dablement, S; Mortensen, D; Fjaer, H; Lee, M; Grandfield, J; Savage, G; Nguyen, V

2012-01-01

Properzi continuous casting is a wheel and belt casting process used for producing aluminium wire rod which is essential to the making of electrical cables and over head lines. One of the main concerns of Properzi process users is to ensure good quality of the final product and to avoid cast defects especially the presence of shrinkage cavity. Numerical models developed with the Alsim software, which allows an automatic calculation of gap dependent heat transfer coefficients at the metal-mould interface due to thermal deformation, are used in order to get a better understanding on the shrinkage cavity formation. Models show the effect of process parameters on the cavity defect development and provide initial guidance for users in order to avoid this kind of casting defect.

Materials requirements for the ITER vacuum vessel and in-vessel components - approaching the construction phase

International Nuclear Information System (INIS)

Barabash, V.; Ioki, K.; Pick, M.; Girard, J.P.; Merola, M.

2007-01-01

Full text of publication follows: The ITER activities are fully devoted toward its construction. In accordance with the ITER integrated project schedule, the procurement specifications for the manufacturing of the Vacuum Vessel should be prepared by March 2008 and the procurement specifications for the in-vessel components (first wall/blanket, divertor) by 2009. To update the design, considering design and technology evolution, the ITER Design Review has been launched. Among the various topics being discussed are the important issues related to selection of materials, material procurement, and assessment of performance during operation. The main requirements related to materials for the vacuum vessel and the in-vessel components are summarized in the paper. The specific licensing requirements are to be followed for structural materials of pressure and nuclear pressure equipment components for construction of ITER. In addition, the procurements in ITER will be done mostly 'in-kind' and it is assumed that materials for these components will be produced by different Parties. However, in accordance with the regulatory requirements and quality requirements for operation, common specifications and the general rules to fulfill these requirements are to be adopted. For some ITER components (e.g. first wall, divertor high heat flux components), the ultimate qualification of the joining technologies (Be/Cu, SS/Cu, CFC/Cu, W/Cu) is under final evaluation. Successful accomplishment of the qualification program will allow to proceed with procurements of the components for ITER. The criteria for acceptance of these components and materials after manufacturing are described and the main results will be reported. Additional materials issues, which come from the on-going manufacturing R and D program, will be also described. Finally, further materials activity during the construction phase, needs for final qualification and acceptance of materials are discussed. (authors)

Use of rice husk ash for mitigating the autogenous shrinkage of cement pastes at low water cement ratio

NARCIS (Netherlands)

Huang, H.; Ye, G.; Fehling, Ekkehard; Middendorf, Bernhard; Thiemicke, Jenny

2016-01-01

It is well recognized that the high risk of early age micro-crack of HPC/UHPC is attributed to the large magnitude of early age autogenous shrinkage caused by self-desiccation in binder hydration. Over the years, several methods have been proposed to mitigate autogenous shrinkage based on internal

ITER technology R and D progress report. Report by the Director. ITER technical advisory committee meeting, 25-27 June 2000, St. Petersburg

International Nuclear Information System (INIS)

2001-01-01

The overall philosophy for the ITER design has been to use established approaches through detailed analysis and to validate their application to ITER through technology R and D, including fabrication of full scale or scalable models of key components. All this R and D work has been done for ITER under collaboration among the Home Teams, with a total resource of about 660 KIUA. R and D issues for ITER-FEAT are almost the same as for the 1998 ITER design. Major developments and fabrication have been completed and tests have significantly progressed. The technical output from the R and D validates the technologies and confirms the manufacturing techniques and quality assurance incorporated in the ITER design, and supports the manufacturing cost estimates for important key cost drivers. The testing of models is continuing to demonstrate their performance margin and/or to optimize their operational use. Their realisation offers insights useful for a possible future collaborative construction activity. Valuable and relevant experience has already been gained in the management of industrial scale, cross-party ventures. The successful progress of these projects increases confidence in the possibility of jointly constructing ITER in an international project framework. The R and D present status is summarized in the following: details are given in Chapters 2 and 3. Significant efforts and resources have been devoted to the Seven Large R and D Projects which cover all the major key components of the basic machine of ITER and their maintenance tools

Thermo-hydraulic and structural analysis for finger-based concept of ITER blanket first wall

International Nuclear Information System (INIS)

Kim, Byoung-Yoon; Ahn, Hee-Jae

2011-01-01

The blanket first wall is one of the main plasma facing components in ITER tokamak. The finger-typed first wall was proposed through the current design progress by ITER organization. In this concept, each first wall module is composed of a beam and twenty fingers. The main function of the first wall is to remove efficiently the high heat flux loading from the fusion plasma during its operation. Therefore, the thermal and structural performance should be investigated for the proposed finger-based design concept of first wall. The various case studies were performed for a unit finger model considering different loading conditions. The finite element model was made for a half of a module using symmetric boundary conditions to reduce the computational effort. The thermo-hydraulic analysis was performed to obtain the pressure drop and temperature profiles. Then the structural analysis was carried out using the maximum temperature distribution obtained in thermo-hydraulic analysis. Finally, the transient thermo-hydraulic analysis was performed for the generic first wall module to obtain the temperature evolution history considering cyclic heat flux loading with nuclear heating. After that, the thermo-mechanical analysis was performed at the time step when the maximum temperature gradient was occurred. Also, the stress analysis was performed for the component with a finger and a beam to check the residual stress of the component after thermal shrinkage assembly.

Evaluation of linear polymerization shrinkage, flexural strength and modulus of elasticity of dental composites

Directory of Open Access Journals (Sweden)

Gabriela Queiroz de Melo Monteiro

2010-03-01

Full Text Available Linear polymerization shrinkage (LPS, flexural strength (FS and modulus of elasticity (ME of 7 dental composites (Filtek Z350™, Filtek Z250™/3M ESPE; Grandio™, Polofil Supra™/VOCO; TPH Spectrum™, TPH3™, Esthet-X™/Denstply were measured. For the measurement of LPS, composites were applied to a cylindrical metallic mold and polymerized (n = 8. The gap formed at the resin/mold interface was observed using scanning electron microscopy (1500×. For FS and ME, specimens were prepared according to the ISO 4049 specifications (n = 10. Statistical analysis of the data was performed with one-way ANOVA and the Tukey test. TPH Spectrum presented significantly higher LPS values (29.45 µm. Grandio had significantly higher mean values for FS (141.07 MPa and ME (13.91 GPa. The relationship between modulus of elasticity and polymerization shrinkage is the main challenge for maintenance of the adhesive interface, thus composites presenting high shrinkage values, associated with a high modulus of elasticity tend to disrupt the adhesive interface under polymerization.

Seeing without the Occipito-Parietal Cortex: Simultagnosia as a Shrinkage of the Attentional Visual Field

Directory of Open Access Journals (Sweden)

François Michel

2004-01-01

Full Text Available Following bi-parietal lesions patient AT showed a severe inability to relocate her attention within a visual field which perimetry proved to be near-normal. An experimental approach with tasks testing visuo-spatial attention demonstrated a shrinkage of A.T.’s attentional visual field. With her visual attention narrowed to a kind of functional tunnel vision, the patient exhibited simultanagnosia (Wolpert, 1924, a symptom previously described in 1909 by Balint under the label of Psychic paralysis of “Gaze”. In striking contrast AT showed an efficient and effortless perception of complex natural scenes, which, according to recent work in normal subjects, necessitate few if any attentional resources.

Report of panel 1: The appropriate scope and mission of ITER

Energy Technology Data Exchange (ETDEWEB)

Linford, R.K. (Los Alamos National Lab., NM (United States)); Weitzner, H.; Abdou, M.A.; Baldwin, D.E.; Berkner, K.H.; Berry, L.A.; Culler, F.L.; Dean, S.O.; DeFreece, D.A.; Gauster, W.B. (and others)

1992-12-01

This panel looked at the mission of ITER, and how the US should address the present plans, and considers a number of alternative plans to arrive at the eventual goals of ITER. The panel considered three major approaches which have been discussed on the international scale, and tries to present the strengths, weaknesses, and possible changes to these plans. It suggests that any of these plans can arrive at the eventual aim, but may involve differing risks and time commitments. All plans involve ITER design studies, development work on technologies which must be in place for ITER design to succeed, and testing of materials and components for application in the device.

Report of panel 1: The appropriate scope and mission of ITER

International Nuclear Information System (INIS)

Linford, R.K.; Weitzner, H.; Abdou, M.A.; Baldwin, D.E.; Berkner, K.H.; Berry, L.A.; Culler, F.L.; Dean, S.O.; DeFreece, D.A.; Gauster, W.B.

1992-01-01

This panel looked at the mission of ITER, and how the US should address the present plans, and considers a number of alternative plans to arrive at the eventual goals of ITER. The panel considered three major approaches which have been discussed on the international scale, and tries to present the strengths, weaknesses, and possible changes to these plans. It suggests that any of these plans can arrive at the eventual aim, but may involve differing risks and time commitments. All plans involve ITER design studies, development work on technologies which must be in place for ITER design to succeed, and testing of materials and components for application in the device

Some Matrix Iterations for Computing Generalized Inverses and Balancing Chemical Equations

Directory of Open Access Journals (Sweden)

Farahnaz Soleimani

2015-11-01

Full Text Available An application of iterative methods for computing the Moore–Penrose inverse in balancing chemical equations is considered. With the aim to illustrate proposed algorithms, an improved high order hyper-power matrix iterative method for computing generalized inverses is introduced and applied. The improvements of the hyper-power iterative scheme are based on its proper factorization, as well as on the possibility to accelerate the iterations in the initial phase of the convergence. Although the effectiveness of our approach is confirmed on the basis of the theoretical point of view, some numerical comparisons in balancing chemical equations, as well as on randomly-generated matrices are furnished.

In-Situ Observation of Sintering Shrinkage of UO2 Compacts Derived from Different Powder Routes

International Nuclear Information System (INIS)

Rhee, Young Woo; Oh, Jang Soo; Kim, Dong Joo; Kim, Keon Sik; Kim, Jong Hun; Yang, Jae Ho; Koo, Yang Hyun

2015-01-01

In-situ observations on the shrinkage of green pellets with precisely controlled dimensions were carefully conducted by using TOM during H2 atmosphere sintering. The shrinkage retardation in IDR-UO 2 might be attributed to the larger primary particle size of IDRUO 2 than those of ADU- and AUC- UO 2 powders. It would be important to understand the different sintering characteristics of UO 2 powders according to the powder routes, when it comes to designing a new sintering process or choosing a sintering additive for new fuel pellet like PCI (Pellet Cladding Interaction) remedy pellet. In this paper, we have investigated the initial and intermediate sintering shrinkage of UO 2 from different powder routes by in-situ observation of green samples during H2 atmosphere sintering. Effect of powder characteristics of three different UO 2 powders on the initial and intermediate sintering were closely reviewed including crystal structure, powder size, specific surface area, primary crystal size, and O/U ratio

Effectiveness of Fiber Reinforcement on the Mechanical Properties and Shrinkage Cracking of Recycled Fine Aggregate Concrete

Science.gov (United States)

Nam, Jeongsoo; Kim, Gyuyong; Yoo, Jaechul; Choe, Gyeongcheol; Kim, Hongseop; Choi, Hyeonggil; Kim, Youngduck

2016-01-01

This paper presents an experimental study conducted to investigate the effect of fiber reinforcement on the mechanical properties and shrinkage cracking of recycled fine aggregate concrete (RFAC) with two types of fiber—polyvinyl alcohol (PVA) and nylon. A small fiber volume fraction, such as 0.05% or 0.1%, in RFAC with polyvinyl alcohol or nylon fibers was used for optimum efficiency in minimum quantity. Additionally, to make a comparative evaluation of the mechanical properties and shrinkage cracking, we examined natural fine aggregate concrete as well. The test results revealed that the addition of fibers and fine aggregates plays an important role in improving the mechanical performance of the investigated concrete specimens as well as controlling their cracking behavior. The mechanical properties such as compressive strength, splitting tensile strength, and flexural strength of fiber-reinforced RFAC were slightly better than those of non-fiber-reinforced RFAC. The shrinkage cracking behavior was examined using plat-ring-type and slab-type tests. The fiber-reinforced RFAC showed a greater reduction in the surface cracks than non-fiber-reinforced concrete. The addition of fibers at a small volume fraction in RFAC is more effective for drying shrinkage cracks than for improving mechanical performance. PMID:28773256

Effectiveness of Fiber Reinforcement on the Mechanical Properties and Shrinkage Cracking of Recycled Fine Aggregate Concrete.

Science.gov (United States)

Nam, Jeongsoo; Kim, Gyuyong; Yoo, Jaechul; Choe, Gyeongcheol; Kim, Hongseop; Choi, Hyeonggil; Kim, Youngduck

2016-02-26

This paper presents an experimental study conducted to investigate the effect of fiber reinforcement on the mechanical properties and shrinkage cracking of recycled fine aggregate concrete (RFAC) with two types of fiber-polyvinyl alcohol (PVA) and nylon. A small fiber volume fraction, such as 0.05% or 0.1%, in RFAC with polyvinyl alcohol or nylon fibers was used for optimum efficiency in minimum quantity. Additionally, to make a comparative evaluation of the mechanical properties and shrinkage cracking, we examined natural fine aggregate concrete as well. The test results revealed that the addition of fibers and fine aggregates plays an important role in improving the mechanical performance of the investigated concrete specimens as well as controlling their cracking behavior. The mechanical properties such as compressive strength, splitting tensile strength, and flexural strength of fiber-reinforced RFAC were slightly better than those of non-fiber-reinforced RFAC. The shrinkage cracking behavior was examined using plat-ring-type and slab-type tests. The fiber-reinforced RFAC showed a greater reduction in the surface cracks than non-fiber-reinforced concrete. The addition of fibers at a small volume fraction in RFAC is more effective for drying shrinkage cracks than for improving mechanical performance.

Statistical mechanics provides novel insights into microtubule stability and mechanism of shrinkage.

Directory of Open Access Journals (Sweden)

Ishutesh Jain

2015-02-01

Full Text Available Microtubules are nano-machines that grow and shrink stochastically, making use of the coupling between chemical kinetics and mechanics of its constituent protofilaments (PFs. We investigate the stability and shrinkage of microtubules taking into account inter-protofilament interactions and bending interactions of intrinsically curved PFs. Computing the free energy as a function of PF tip position, we show that the competition between curvature energy, inter-PF interaction energy and entropy leads to a rich landscape with a series of minima that repeat over a length-scale determined by the intrinsic curvature. Computing Langevin dynamics of the tip through the landscape and accounting for depolymerization, we calculate the average unzippering and shrinkage velocities of GDP protofilaments and compare them with the experimentally known results. Our analysis predicts that the strength of the inter-PF interaction (E(s(m has to be comparable to the strength of the curvature energy (E(b(m such that E(s(m - E(b(m ≈ 1kBT, and questions the prevalent notion that unzippering results from the domination of bending energy of curved GDP PFs. Our work demonstrates how the shape of the free energy landscape is crucial in explaining the mechanism of MT shrinkage where the unzippered PFs will fluctuate in a set of partially peeled off states and subunit dissociation will reduce the length.

ITER, the 'Broader Approach', a DEMO fusion reactor

International Nuclear Information System (INIS)

Janeschitz, G.; Bahm, W.

2007-01-01

Fusion is a very promising future energy option, which is characterized by almost unlimited fuel reserves, favourable safety features and environmental sustainability. The aim of the worldwide fusion research is a fusion power station which imitates the process taking place in the sun and thus gains energy from the fusion of light atomic nuclei. The experimental reactor ITER which will be built in Cadarache, France, marks a breakthrough in the worldwide fusion research: For the first time an energy multiplication factor of at least 10 will be achieved, the factor by which the fusion power exceeds the external plasma heating. Partners in this project are the European Union, Japan, the Russian Federation, USA, China, South Korea and India as well as Brazil as associated partner. The facility is supposed to demonstrate a long burning, reactor-typical plasma and to test techniques such as plasma heating, plasma confinement by superconducting magnets, fuel cycle as well as energy transition, tritium breeding and remote handling technologies. The next step beyond ITER will be the demonstration power station DEMO which requires further developments in order to create the basis for its design and construction. The roadmap to fusion energy is described. It consists of several elements which are needed to develop the knowledge required for a commercial fusion reactor. The DEMO time schedule depends on the efforts in terms of personnel and budget resources the society is willing to invest in fusion taking into account the long term energy supply and its environmental impact. (orig.)

clınıcal EVALUATION OF FREE GINGIVAL GRAFT SHRINKAGE IN HORIZONTAL AND VERTICAL DIMENSIONS

Directory of Open Access Journals (Sweden)

Emine ÇİFCİBAŞI

2015-10-01

Full Text Available Purpose: To assess the shrinkage of Free Gingival Graft (FGG in horizontal and vertical dimensions and calculate the changes in the surface area of the transplanted tissue in a 3 months period. Materials and Methods: A total of 30 FGG were placed aiming to increase attached gingiva around recession sites. Vertical recessions, horizontal recessions, surface area, plaque index, gingival index, periodontal probing depth and clinical attachment level were assesed at baseline, 1 and 3 months postoperatively. Results: Graft shrinkage between baseline and 1 month was more evident than 1 to 3 months in either dimensions. Both horizontal and vertical dimensions were significantly decreased (p0.05. . Conclusion: The shrinkage of vertical and horizontal dimensions of the grafts were almost equal unlike the literature. In addition, the different dimensional changes observed in individual level deserve further research.

A semi-automated 2D/3D marker-based registration algorithm modelling prostate shrinkage during radiotherapy for prostate cancer

International Nuclear Information System (INIS)

Budiharto, Tom; Slagmolen, Pieter; Hermans, Jeroen; Maes, Frederik; Verstraete, Jan; Heuvel, Frank Van den; Depuydt, Tom; Oyen, Raymond; Haustermans, Karin

2009-01-01

Background and purpose: Currently, most available patient alignment tools based on implanted markers use manual marker matching and rigid registration transformations to measure the needed translational shifts. To quantify the particular effect of prostate gland shrinkage, implanted gold markers were tracked during a course of radiotherapy including an isotropic scaling factor to model prostate shrinkage. Materials and methods: Eight patients with prostate cancer had gold markers implanted transrectally and seven were treated with (neo) adjuvant androgen deprivation therapy. After patient alignment to skin tattoos, orthogonal electronic portal images (EPIs) were taken. A semi-automated 2D/3D marker-based registration was performed to calculate the necessary couch shifts. The registration consists of a rigid transformation combined with an isotropic scaling to model prostate shrinkage. Results: The inclusion of an isotropic shrinkage model in the registration algorithm cancelled the corresponding increase in registration error. The mean scaling factor was 0.89 ± 0.09. For all but two patients, a decrease of the isotropic scaling factor during treatment was observed. However, there was almost no difference in the translation offset between the manual matching of the EPIs to the digitally reconstructed radiographs and the semi-automated 2D/3D registration. A decrease in the intermarker distance was found correlating with prostate shrinkage rather than with random marker migration. Conclusions: Inclusion of shrinkage in the registration process reduces registration errors during a course of radiotherapy. Nevertheless, this did not lead to a clinically significant change in the proposed table translations when compared to translations obtained with manual marker matching without a scaling correction

Design approach of seismic interface for cryoline with Tokamak building for ITER

International Nuclear Information System (INIS)

Badgujar, S.; Sarkar, B.; Vaghela, H.; Shah, N.; Naik, H.B.

2012-01-01

ITER Tokamak building is designed with seismic isolation pads to protect the Tokamak components from seismic events. Two main cryolines, designated as cryolines between buildings (Mg and CP), runs from interconnection box in cryoplant building to the Tokamak building. The lines outside Tokamak building are supported by seismically non-isolated supports. The cryoline design at the interface between seismically isolated and non-isolated support systems needs to be studied to fulfill the functional requirements. One of the options for interface, universal expansion joint has been modeled in CATIA with actual thickness of each ply and inter-ply distance, analyzed in ANSYS using contact definition, as a part of the preliminary study. The bellows have been checked by design calculation as per EJMA standard for the specified movements. The paper will present approach for conceptual design of interface, problem definition and boundary conditions, methodology for analysis and preliminary results of stress pattern for expansion joints. (author)

Denoising of Mechanical Vibration Signals Using Quantum-Inspired Adaptive Wavelet Shrinkage

Directory of Open Access Journals (Sweden)

Yan-long Chen

2014-01-01

Full Text Available The potential application of a quantum-inspired adaptive wavelet shrinkage (QAWS technique to mechanical vibration signals with a focus on noise reduction is studied in this paper. This quantum-inspired shrinkage algorithm combines three elements: an adaptive non-Gaussian statistical model of dual-tree complex wavelet transform (DTCWT coefficients proposed to improve practicability of prior information, the quantum superposition introduced to describe the interscale dependencies of DTCWT coefficients, and the quantum-inspired probability of noise defined to shrink wavelet coefficients in a Bayesian framework. By combining all these elements, this signal processing scheme incorporating the DTCWT with quantum theory can both reduce noise and preserve signal details. A practical vibration signal measured from a power-shift steering transmission is utilized to evaluate the denoising ability of QAWS. Application results demonstrate the effectiveness of the proposed method. Moreover, it achieves better performance than hard and soft thresholding.

Evaluation of shrinkage polymerization and temperature of different acrylic resins used to splinting transfer copings in indirect impression technique

Science.gov (United States)

Franco, Ana Paula G. O.; Karam, Leandro Z.; Galvão, José R.; Kalinowski, Hypolito J.

2015-09-01

The aim of the present study was evaluate the shrinkage polymerization and temperature of different acrylic resins used to splinting transfer copings in indirect impression technique. Two implants were placed in an artificial bone, with the two transfer copings joined with dental floss and acrylic resins; two dental resins are used. Measurements of deformation and temperature were performed with Fiber Braggs grating sensor for 17 minutes. The results revealed that one type of resin shows greater values of polymerization shrinkage than the other. Pattern resins did not present lower values of shrinkage, as usually reported by the manufacturer.

ITER council proceedings: 1998

International Nuclear Information System (INIS)

1999-01-01

This volume contains documents of the 13th and the 14th ITER council meeting as well as of the 1st extraordinary ITER council meeting. Documents of the ITER meetings held in Vienna and Yokohama during 1998 are also included. The contents include an outline of the ITER objectives, the ITER parameters and design overview as well as operating scenarios and plasma performance. Furthermore, design features, safety and environmental characteristics are given

A moment projection method for population balance dynamics with a shrinkage term

Energy Technology Data Exchange (ETDEWEB)

Wu, Shaohua [Department of Mechanical Engineering, National University of Singapore, Engineering Block EA, Engineering Drive 1, 117576 (Singapore); Yapp, Edward K.Y.; Akroyd, Jethro; Mosbach, Sebastian [Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, CB2 3RA (United Kingdom); Xu, Rong [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 (Singapore); Yang, Wenming [Department of Mechanical Engineering, National University of Singapore, Engineering Block EA, Engineering Drive 1, 117576 (Singapore); Kraft, Markus, E-mail: mk306@cam.ac.uk [Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, CB2 3RA (United Kingdom); School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 (Singapore)

2017-02-01

A new method of moments for solving the population balance equation is developed and presented. The moment projection method (MPM) is numerically simple and easy to implement and attempts to address the challenge of particle shrinkage due to processes such as oxidation, evaporation or dissolution. It directly solves the moment transport equation for the moments and tracks the number of the smallest particles using the algorithm by Blumstein and Wheeler (1973) . The performance of the new method is measured against the method of moments (MOM) and the hybrid method of moments (HMOM). The results suggest that MPM performs much better than MOM and HMOM where shrinkage is dominant. The new method predicts mean quantities which are almost as accurate as a high-precision stochastic method calculated using the established direct simulation algorithm (DSA).

Iter

Science.gov (United States)

Iotti, Robert

2015-04-01

ITER is an international experimental facility being built by seven Parties to demonstrate the long term potential of fusion energy. The ITER Joint Implementation Agreement (JIA) defines the structure and governance model of such cooperation. There are a number of necessary conditions for such international projects to be successful: a complete design, strong systems engineering working with an agreed set of requirements, an experienced organization with systems and plans in place to manage the project, a cost estimate backed by industry, and someone in charge. Unfortunately for ITER many of these conditions were not present. The paper discusses the priorities in the JIA which led to setting up the project with a Central Integrating Organization (IO) in Cadarache, France as the ITER HQ, and seven Domestic Agencies (DAs) located in the countries of the Parties, responsible for delivering 90%+ of the project hardware as Contributions-in-Kind and also financial contributions to the IO, as ``Contributions-in-Cash.'' Theoretically the Director General (DG) is responsible for everything. In practice the DG does not have the power to control the work of the DAs, and there is not an effective management structure enabling the IO and the DAs to arbitrate disputes, so the project is not really managed, but is a loose collaboration of competing interests. Any DA can effectively block a decision reached by the DG. Inefficiencies in completing design while setting up a competent organization from scratch contributed to the delays and cost increases during the initial few years. So did the fact that the original estimate was not developed from industry input. Unforeseen inflation and market demand on certain commodities/materials further exacerbated the cost increases. Since then, improvements are debatable. Does this mean that the governance model of ITER is a wrong model for international scientific cooperation? I do not believe so. Had the necessary conditions for success

A modelling study of drying shrinkage damage in concrete repair systems

NARCIS (Netherlands)

Lukovic, M.; Savija, B.; Schlangen, E.; Ye, G.; van Breugel, K.

2014-01-01

Differential shrinkage between repair material and concrete substrate is considered to be the main cause of premature failure of repair systems (Martinola, Sadouki et al. 2001, Beushausen and Alexander 2007). Magnitude of induced stresses depends on many factors, for example the amount of restraint,

Porous stainless steel hollow fibers with shrinkage-controlled small radial dimensions

NARCIS (Netherlands)

Luiten-Olieman, Maria W.J.; Raaijmakers, Michiel; Raaijmakers, Michiel J.T.; Winnubst, Aloysius J.A.; Wessling, Matthias; Nijmeijer, Arian; Benes, Nieck Edwin

2011-01-01

A method is presented for the preparation of thin (∼250 μm) porous stainless steel hollow fiber membranes based on dry–wet spinning of a particle-loaded polymer solution followed by heat treatment. Extraordinarily small radial dimensions were achieved by controlled shrinkage during thermal

A comparative study of bulk-fill composites: degree of conversion, post-gel shrinkage and cytotoxicity

Directory of Open Access Journals (Sweden)

Flávia Gonçalves

2018-03-01

Full Text Available Abstract: Bulk-fill composites are claimed to be restorative materials used in deep preparations and effectively photoactivated in layers up to 4 mm. The aim of the present study was to evaluate the degree of conversion, post-gel volumetric shrinkage, and cytotoxicity of six bulk-fill and two conventional composites. Degree of conversion was determined by FTIR spectroscopy; post-gel volumetric shrinkage was determined using the strain gauge method; and cytotoxicity in human fibroblasts was evaluated indirectly by the MTT assay. Data were subjected to one-way ANOVA/Tukey's test (α = 0.05. All materials, including bulk-fill and conventional composites, were classified as non-toxic, with cell viability higher than 70%. Bulk-fill composites exhibited volumetric shrinkage similar to or lower (1.4 to 0.4% than that of conventional composites (1.7–2.1%. However, only four of the bulk-fill composites were able to sustain a homogeneous conversion at the 4-mm depth. Despite their non-toxicity and shrinkage similar to that of conventional materials, not all commercial bulk-fill materials were able to maintain a conversion as high as 80% of the superficial layer, at the 4-mm depth, indicating some failure in the bulk-fill design of some commercial brands. Therefore, the use of bulk-fill materials in dental practice is advantageous, but special attention should be given to the selection and correct use of the materials.

Evaluation of Continuation Desire as an Iterative Game Development Method

DEFF Research Database (Denmark)

Schoenau-Fog, Henrik; Birke, Alexander; Reng, Lars

2012-01-01

When developing a game it is always valuable to use feedback from players in each iteration, in order to plan the design of the next iteration. However, it can be challenging to devise a simple approach to acquiring information about a player's engagement while playing. In this paper we will thus...... concerning a crowd game which is controlled by smartphones and is intended to be played by audiences in cinemas and at venues with large screens. The case study demonstrates how the approach can be used to help improve the desire to continue when developing a game....

ITER, a major step toward nuclear fusion energy; ITER, une etape majeure vers l'energie de fusion

Energy Technology Data Exchange (ETDEWEB)

Ikeda, K.; Holtkamp, N.; Pick, M.; Gauche, F.; Garin, P.; Bigot, B.; Luciani, J.F.; Mougniot, J.C.; Watteau, J.P.; Saoutic, B.; Becoulet, A.; Libeyre, P.; Beaumont, B.; Simonin, A.; Giancarli, L.; Rosenvallon, S.; Gastaldi, O.; Marbach, G.; Boudot, C.; Ioki, K.; Mitchell, N.; Girard, J.Ph.; Giraud, B.; Lignini, F.; Giguet, E.; Bofusch, E.; Friconneau, J.P.; Di Pace, L.; Pampin, R.; Cook, I.; Maisonnier, D.; Campbell, D.; Hayward, J.; Li Puma, A.; Norajitra, P.; Sardain, P.; Tran, M.Q.; Ward, D.; Moslang, A.; Carre, F.; Serpantie, J.P

2007-01-15

This document gathers together a series of articles dedicated to ITER. They are organized into 5 parts. The first part describes the potential of fusion as a source of energy that will be able to face the challenge of a continuously increasing demand. After a reminder of the main fusion reactions and the conditions to obtain fusion, the second part focuses on the magnetic fusion based concepts with a special emphasis on the tokamak configuration. In the third part the main components of ITER are described: first the plasma facing components, then the vacuum vessel, the superconducting magnets and the heating systems. In the fourth part short papers concerning ITER safety, the maintenance through remote handling systems, the tritium breeding blanket, are given, along with a full article on the waste management. It is interesting to notice that the nuclear wastes will represent: -) between 1600 and 3800 tons of housekeeping and process wastes produced during the 20 years of operation of ITER (20% very low level waste, 75% low or medium activity with short life and 5% medium activity with long life), -) about 750 tons from component replacement during ITER active operation, and -) about 30000 tons from the decommissioning of ITER. The last part presents the European concepts for a power plant based on a fusion reactor. A basic design is given along with a state of the art of the research on the materials that will be used for the structures. It is highlighted that synergies between fission and fusion technologies exist in at least 4 areas: nuclear design code system, high temperature materials, safety approach, and in-service inspection, maintenance and dismantling. (A.C.)

Porcine intestinal mast cells. Evaluation of different fixatives for histochemical staining techniques considering tissue shrinkage

Directory of Open Access Journals (Sweden)

J. Rieger

2013-07-01

Full Text Available Staining of mast cells (MCs, including porcine ones, is critically dependent upon the fixation and staining technique. In the pig, mucosal and submucosal MCs do not stain or stain only faintly after formalin fixation. Some fixation methods are particularly recommended for MC staining, for example the fixation with Carnoy or lead salts. Zinc salt fixation (ZSF has been reported to work excellently for the preservation of fixation-sensitive antigens. The aim of this study was to establish a reliable histological method for counting of MCs in the porcine intestinum. For this purpose, different tissue fixation and staining methods that also allow potential subsequent immunohistochemical investigations were evaluated in the porcine mucosa, as well as submucosa of small and large intestine. Tissues were fixed in Carnoy, lead acetate, lead nitrate, Zamboni and ZSF and stained subsequently with either polychromatic methylene blue, alcian blue or toluidine blue. For the first time our study reveals that ZSF, a heavy metal fixative, preserves metachromatic staining of porcine MCs. Zamboni fixation was not suitable for histochemical visualization of MCs in the pig intestine. All other tested fixatives were suitable. Alcian blue and toluidine blue co-stained intestinal goblet cells which made a prima facie identification of MCs difficult. The polychromatic methylene blue proved to be the optimal staining. In order to compare MC counting results of the different fixation methods, tissue shrinkage was taken into account. As even the same fixation caused shrinkage-differences between tissue from small and large intestine, different factors for each single fixation and intestinal localization had to be calculated. Tissue shrinkage varied between 19% and 57%, the highest tissue shrinkage was found after fixation with ZSF in the large intestine, the lowest one in the small intestine after lead acetate fixation. Our study emphasizes that MC counting results from

Mechanical properties and polymerization shrinkage of composite resins light-cured using two different lasers.

Science.gov (United States)

Kim, Tae-Wan; Lee, Jang-Hoon; Jeong, Seung-Hwa; Ko, Ching-Chang; Kim, Hyung-Il; Kwon, Yong Hoon

2015-04-01

The purpose of the present study was to investigate the usefulness of 457 and 473 nm lasers for the curing of composite resins during the restoration of damaged tooth cavity. Monochromaticity and coherence are attractive features of laser compared with most other light sources. Better polymerization of composite resins can be expected. Eight composite resins were light cured using these two lasers and a light-emitting diode (LED) light-curing unit (LCU). To evaluate the degrees of polymerization achieved, polymerization shrinkage and flexural and compressive properties were measured and compared. Polymerization shrinkage values by 457 and 473 nm laser, and LED ranged from 10.9 to 26.8, from 13.2 to 26.1, and from 11.5 to 26.3 μm, respectively. The values by 457 nm laser was significantly different from those by 473 and LED LCU (p0.05). For the tested LCUs, no specific LCU could consistently achieve highest strength and modulus from the specimens tested. Two lasers (457 and 473 nm) can polymerize composite resins to the level that LED LCU can achieve despite inconsistent trends of polymerization shrinkage and flexural and compressive properties of the tested specimens.

International Symposium on Fundamental Research on Creep and Shrinkage of Concrete

CERN Document Server

1982-01-01

Today research on creep and shrinkage of concrete is diversified to such a degree that specialists working in different areas sometimes find it difficult to understand one-another. Materials scientists are mainly interested in processes on a microstructural level but they do not necessarily understand the relevance of time dependent deformation in structural design. On the other hand engineers who apply simplified model laws in non-elastic structural analysis are not always in the position to judge the limitations implied in their approach. It is generally realized that further development can be stimulated by a more effective exchange of results and ideas among the different groups involved. In an attempt to bridge this obvious gap in September 1980 there was a Conference organized at Swiss Federal Institute of Technology in Lausanne. The papers presented at this meeting covered the wide range starting with microstructural aspects and mechanisms and including constitutive modelling and structural creep analy...

Structural analysis of the ITER Vacuum Vessel regarding 2012 ITER Project-Level Loads

Energy Technology Data Exchange (ETDEWEB)

Martinez, J.-M., E-mail: jean-marc.martinez@live.fr [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Jun, C.H.; Portafaix, C.; Choi, C.-H.; Ioki, K.; Sannazzaro, G.; Sborchia, C. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Cambazar, M.; Corti, Ph.; Pinori, K.; Sfarni, S.; Tailhardat, O. [Assystem EOS, 117 rue Jacquard, L' Atrium, 84120 Pertuis (France); Borrelly, S. [Sogeti High Tech, RE2, 180 rue René Descartes, Le Millenium – Bat C, 13857 Aix en Provence (France); Albin, V.; Pelletier, N. [SOM Calcul – Groupe ORTEC, 121 ancien Chemin de Cassis – Immeuble Grand Pré, 13009 Marseille (France)

2014-10-15

Highlights: • ITER Vacuum Vessel is a part of the first barrier to confine the plasma. • ITER Vacuum Vessel as Nuclear Pressure Equipment (NPE) necessitates a third party organization authorized by the French nuclear regulator to assure design, fabrication, conformance testing and quality assurance, i.e. Agreed Notified Body (ANB). • A revision of the ITER Project-Level Load Specification was implemented in April 2012. • ITER Vacuum Vessel Loads (seismic, pressure, thermal and electromagnetic loads) were summarized. • ITER Vacuum Vessel Structural Margins with regards to RCC-MR code were summarized. - Abstract: A revision of the ITER Project-Level Load Specification (to be used for all systems of the ITER machine) was implemented in April 2012. This revision supports ITER's licensing by accommodating requests from the French regulator to maintain consistency with the plasma physics database and our present understanding of plasma transients and electro-magnetic (EM) loads, to investigate the possibility of removing unnecessary conservatism in the load requirements and to review the list and definition of incidental cases. The purpose of this paper is to present the impact of this 2012 revision of the ITER Project-Level Load Specification (LS) on the ITER Vacuum Vessel (VV) loads and the main structural margins required by the applicable French code, RCC-MR.

Recent Progress on ECH Technology for ITER

Science.gov (United States)

Sirigiri, Jagadishwar

2005-10-01

The Electron Cyclotron Heating and Current Drive (ECH&CD) system for ITER is a critical ITER system that must be available for use on Day 1 of the ITER experimental program. The applications of the system include plasma start-up, plasma heating and suppression of Neoclassical Tearing Modes (NTMs). These applications are accomplished using 27 one megawatt continuous wave gyrotrons: 24 at a frequency of 170 GHz and 3 at a frequency of 120 GHz. There are DC power supplies for the gyrotrons, a transmission line system, one launcher at the equatorial plane and three upper port launchers. The US will play a major role in delivering parts of the ECH&CD system to ITER. The present state-of-the-art includes major advances in all areas of ECH technology. In the US, a major effort is underway to supply gyrotrons of up to 1.5 MW power level at 110 GHz to General Atomics for use in heating the DIII-D tokamak. This presentation will include a brief review of the state-of-the-art, worldwide, in ECH technology. The requirements for the ITER ECH&CD system will then be reviewed. ITER calls for gyrotrons capable of operating from a 50 kV power supply, after potential depression, with a minimum of 50% overall efficiency. This is a very significant challenge and some approaches to meeting this goal will be presented. Recent experimental results at MIT showing improved efficiency of high frequency, 1.5 MW gyrotrons will be described. These results will be incorporated into the planned development of gyrotrons for ITER. The ITER ECH&CD system will also be a challenge to the transmission lines, which must operate at high average power at up to 1000 seconds and with high efficiency. The technology challenges and efforts in the US and other ITER parties to solve these problems will be reviewed. *In collaboration with E. Choi, C. Marchewka, I. Mastovosky, M. A. Shapiro and R. J. Temkin. This work is supported by the Office of Fusion Energy Sciences of the U. S. Department of Energy.

ITER test programme

International Nuclear Information System (INIS)

Abdou, M.; Baker, C.; Casini, G.

1991-01-01

ITER has been designed to operate in two phases. The first phase which lasts for 6 years, is devoted to machine checkout and physics testing. The second phase lasts for 8 years and is devoted primarily to technology testing. This report describes the technology test program development for ITER, the ancillary equipment outside the torus necessary to support the test modules, the international collaboration aspects of conducting the test program on ITER, the requirements on the machine major parameters and the R and D program required to develop the test modules for testing in ITER. 15 refs, figs and tabs

ITER-FEAT outline design report

International Nuclear Information System (INIS)

2001-01-01

In July 1998 the ITER Parties were unable, for financial reasons, to proceed with construction of the ITER design proposed at that time, to meet the detailed technical objectives and target cost set in 1992. It was therefore decided to investigate options for the design of ITER with reduced technical objectives and with possibly decreased technical margins, whose target construction cost was one half that of the 1998 ITER design, while maintaining the overall programmatic objective. To identify designs that might meet the revised objectives, task forces involving the JCT and Home Teams met during 1998 and 1999 to analyse and compare a range of options for the design of such a device. This led at the end of 1999 to a single configuration for the ITER design with parameters considered to be the most credible consistent with technical limitations and the financial target, yet meeting fully the objectives with appropriate margins. This new design of ITER, called ''ITER-FEAT'', was submitted to the ITER Director to the ITER Parties as the ''ITER-FEAT Outline Design Report'' (ODR) in January 2000, at their meeting in Tokyo. The Parties subsequently conducted their domestic assessments of this report and fed the resulting comments back into the progressing design. The progress on the developing design was reported to the ITER Technical Advisory Committee (TAC) in June 2000 in the report ''Progress in Resolving Open Design Issues from the ODR'' alongside a report on Progress in Technology R and D for ITER. In addition, the progress in the ITER-FEAT Design and Validating R and D was reported to the ITER Parties. The ITER-FEAT design was subsequently approved by the governing body of ITER in Moscow in June 2000 as the basis for the preparation of the Final Design Report, recognising it as a single mature design for ITER consistent with its revised objectives. This volume contains the documents pertinent to the process described above. More detailed technical information

Fast Multi-Symbol Based Iterative Detectors for UWB Communications

Directory of Open Access Journals (Sweden)

Lottici Vincenzo

2010-01-01

Full Text Available Ultra-wideband (UWB impulse radios have shown great potential in wireless local area networks for localization, coexistence with other services, and low probability of interception and detection. However, low transmission power and high multipath effect make the detection of UWB signals challenging. Recently, multi-symbol based detection has caught attention for UWB communications because it provides good performance and does not require explicit channel estimation. Most of the existing multi-symbol based methods incur a higher computational cost than can be afforded in the envisioned UWB systems. In this paper, we propose an iterative multi-symbol based method that has low complexity and provides near optimal performance. Our method uses only one initial symbol to start and applies a decision directed approach to iteratively update a filter template and information symbols. Simulations show that our method converges in only a few iterations (less than 5, and that when the number of symbols increases, the performance of our method approaches that of the ideal Rake receiver.

Cell shrinkage as a signal to apoptosis in NIH 3T3 fibroblasts

DEFF Research Database (Denmark)

Friis, Martin B; Friborg, Christel R; Schneider, Linda

2005-01-01

Cell shrinkage is a hallmark of the apoptotic mode of programmed cell death, but it is as yet unclear whether a reduction in cell volume is a primary activation signal of apoptosis. Here we studied the effect of an acute elevation of osmolarity (NaCl or sucrose additions, final osmolarity 687...... accelerated in fibroblasts overexpressing Rac. Conversely, the activation of the extracellular signal-regulated kinase (Erk1/2) was initially significantly decreased. Subsequent to activation of p38, p53 was activated through serine-15 phosphorylation, and active p53 was translocated from the cytosol......: cellular shrinkage activates Rac, with activation of p38, followed by phosphorylation and nuclear translocation of p53, resulting in permeability increases and caspase-3 activation....

ITER council proceedings: 1995

International Nuclear Information System (INIS)

1996-01-01

Records of the 8. ITER Council Meeting (IC-8), held on 26-27 July 1995, in San Diego, USA, and the 9. ITER Council Meeting (IC-9) held on 12-13 December 1995, in Garching, Germany, are presented, giving essential information on the evolution of the ITER Engineering Design Activities (EDA) and the ITER Interim Design Report Package and Relevant Documents. Figs, tabs

Shrinkage and porosity evolution during air-drying of non-cellular food systems: Experimental data versus mathematical modelling.

Science.gov (United States)

Nguyen, Thanh Khuong; Khalloufi, Seddik; Mondor, Martin; Ratti, Cristina

2018-01-01

In the present work, the impact of glass transition on shrinkage of non-cellular food systems (NCFS) during air-drying will be assessed from experimental data and the interpretation of a 'shrinkage' function involved in a mathematical model. Two NCFS made from a mixture of water/maltodextrin/agar (w/w/w: 1/0.15/0.015) were created out of maltodextrins with dextrose equivalent 19 (MD19) or 36 (MD36). The NCFS made with MD19 had 30°C higher Tg than those with MD36. This information indicated that, during drying, the NCFS with MD19 would pass from rubbery to glassy state sooner than NCFS MD36, for which glass transition only happens close to the end of drying. For the two NCFS, porosity and volume reduction as a function of moisture content were captured with high accuracy when represented by the mathematical models previously developed. No significant differences in porosity and in maximum shrinkage between both samples during drying were observed. As well, no change in the slope of the shrinkage curve as a function of moisture content was perceived. These results indicate that glass transition alone is not a determinant factor in changes of porosity or volume during air-drying. Copyright © 2017 Elsevier Ltd. All rights reserved.

In-Situ Observation of Sintering Shrinkage of UO{sub 2} Compacts Derived from Different Powder Routes

Energy Technology Data Exchange (ETDEWEB)

Rhee, Young Woo; Oh, Jang Soo; Kim, Dong Joo; Kim, Keon Sik; Kim, Jong Hun; Yang, Jae Ho; Koo, Yang Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

In-situ observations on the shrinkage of green pellets with precisely controlled dimensions were carefully conducted by using TOM during H2 atmosphere sintering. The shrinkage retardation in IDR-UO{sub 2} might be attributed to the larger primary particle size of IDRUO{sub 2} than those of ADU- and AUC- UO{sub 2} powders. It would be important to understand the different sintering characteristics of UO{sub 2} powders according to the powder routes, when it comes to designing a new sintering process or choosing a sintering additive for new fuel pellet like PCI (Pellet Cladding Interaction) remedy pellet. In this paper, we have investigated the initial and intermediate sintering shrinkage of UO{sub 2} from different powder routes by in-situ observation of green samples during H2 atmosphere sintering. Effect of powder characteristics of three different UO{sub 2} powders on the initial and intermediate sintering were closely reviewed including crystal structure, powder size, specific surface area, primary crystal size, and O/U ratio.

Radwaste management aspects of the test blanket systems in ITER

Energy Technology Data Exchange (ETDEWEB)

Laan, J.G. van der, E-mail: JaapG.vanderLaan@iter.org [ITER Organization, Route de Vinon sur Verdon, F-13067 Saint Paul Lez Durance (France); Canas, D. [CEA, DEN/DADN, centre de Saclay, F-91191 Gif-sur-Yvette cedex (France); Chaudhari, V. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Iseli, M. [ITER Organization, Route de Vinon sur Verdon, F-13067 Saint Paul Lez Durance (France); Kawamura, Y. [Japan Atomic Energy Agency, Naka-shi, Ibaraki-ken 311-0193 (Japan); Lee, D.W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Petit, P. [European Commission, DG ENER, Brussels (Belgium); Pitcher, C.S.; Torcy, D. [ITER Organization, Route de Vinon sur Verdon, F-13067 Saint Paul Lez Durance (France); Ugolini, D. [Fusion for Energy, Barcelona (Spain); Zhang, H. [China Nuclear Energy Industry Corporation, Beijing 100032 (China)

2016-11-01

Highlights: • Test Blanket Systems are operated in ITER to test tritium breeding technologies. • The in-vessel parts of TBS become radio-active during the ITER nuclear phase. • For each TBM campaign the TBM, its shield and the Pipe Forests are removed. • High tritium contents and novel materials are specific TBS radwaste features. • A preliminary assessment confirmed RW routing, provided its proper conditioning. - Abstract: Test Blanket Systems (TBS) will be operated in ITER in order to prepare the next steps towards fusion power generation. After the initial operation in H/He plasmas, the introduction of D and T in ITER will mark the transition to nuclear operation. The significant fusion neutron production will give rise to nuclear heating and tritium breeding in the in-vessel part of the TBS. The management of the activated and tritiated structures of the TBS from operation in ITER is described. The TBS specific features like tritium breeding and power conversion at elevated temperatures, and the use of novel materials require a dedicated approach, which could be different to that needed for the other ITER equipment.

1.5 MW RF Load for ITER

International Nuclear Information System (INIS)

Ives, Robert Lawrence; Marsden, David; Collins, George; Karimov, Rasul; Mizuhara, Max; Neilson, Jeffrey

2016-01-01

Calabazas Creek Research, Inc. developed a 1.5 MW RF load for the ITER fusion research facility currently under construction in France. This program leveraged technology developed in two previous SBIR programs that successfully developed high power RF loads for fusion research applications. This program specifically focused on modifications required by revised technical performance, materials, and assembly specification for ITER. This program implemented an innovative approach to actively distribute the RF power inside the load to avoid excessive heating or arcing associated with constructive interference. The new design implemented materials and assembly changes required to meet specifications. Critical components were built and successfully tested during the program.

1.5 MW RF Load for ITER

Energy Technology Data Exchange (ETDEWEB)

Ives, Robert Lawrence [Calabazas Creek Research, Inc., San Mateo, CA (United States); Marsden, David [Calabazas Creek Research, Inc., San Mateo, CA (United States); Collins, George [Calabazas Creek Research, Inc., San Mateo, CA (United States); Karimov, Rasul [Calabazas Creek Research, Inc., San Mateo, CA (United States); Mizuhara, Max [Calabazas Creek Research, Inc., San Mateo, CA (United States); Neilson, Jeffrey [Lexam Research, Redwood City, CA (United States)

2016-09-01

Calabazas Creek Research, Inc. developed a 1.5 MW RF load for the ITER fusion research facility currently under construction in France. This program leveraged technology developed in two previous SBIR programs that successfully developed high power RF loads for fusion research applications. This program specifically focused on modifications required by revised technical performance, materials, and assembly specification for ITER. This program implemented an innovative approach to actively distribute the RF power inside the load to avoid excessive heating or arcing associated with constructive interference. The new design implemented materials and assembly changes required to meet specifications. Critical components were built and successfully tested during the program.

Micro-particles in ITER: A comprehensive review

International Nuclear Information System (INIS)

Grisolia, C.; Rosanvallon, S.; Sharpe, Ph.; Winter, J.

2009-01-01

In a fusion reactor like ITER, in-vessel materials are subjected to interactions with the plasma. One of the main consequences of these plasma-material interactions is the creation of co-deposited layers. Due to internal stresses, part of these layers can crack leading to micro particle creation. The purpose of the following paper is to review the Tokamak operation processes which lead to erosion and layer creation. Then, the proportion of these layers that is converted into micro-particles will be evaluated in the case of Tore Supra experiments and extrapolated for ITER. It is major importance to measure the ITER mobilizable dusts present in the Vacuum Vessel and compare the measured quantity with the safety limits. When approaching these limits, removal systems must be used in order to control the in-vessel dust inventory. In the second part of the paper, diagnostics and removal system under development will be presented.

A review of the theoretical and numerical approaches to modeling skyglow: Iterative approach to RTE, MSOS, and two-stream approximation

International Nuclear Information System (INIS)

Kocifaj, Miroslav

2016-01-01

The study of diffuse light of a night sky is undergoing a renaissance due to the development of inexpensive high performance computers which can significantly reduce the time needed for accurate numerical simulations. Apart from targeted field campaigns, numerical modeling appears to be one of the most attractive and powerful approaches for predicting the diffuse light of a night sky. However, computer-aided simulation of night-sky radiances over any territory and under arbitrary conditions is a complex problem that is difficult to solve. This study addresses three concepts for modeling the artificial light propagation through a turbid stratified atmosphere. Specifically, these are two-stream approximation, iterative approach to Radiative Transfer Equation (RTE) and Method of Successive Orders of Scattering (MSOS). The principles of the methods, their strengths and weaknesses are reviewed with respect to their implications for night-light modeling in different environments. - Highlights: • Three methods for modeling nightsky radiance are reviewed. • The two-stream approximation allows for rapid calculation of radiative fluxes. • The above approach is convenient for modeling large uniformly emitting areas. • SOS is applicable to heterogeneous deployment of well-separated cities or towns. • MSOS is generally CPU less-intensive than traditional 3D RTE.

Krylov iterative methods and synthetic acceleration for transport in binary statistical media

International Nuclear Information System (INIS)

Fichtl, Erin D.; Warsa, James S.; Prinja, Anil K.

2009-01-01

In particle transport applications there are numerous physical constructs in which heterogeneities are randomly distributed. The quantity of interest in these problems is the ensemble average of the flux, or the average of the flux over all possible material 'realizations.' The Levermore-Pomraning closure assumes Markovian mixing statistics and allows a closed, coupled system of equations to be written for the ensemble averages of the flux in each material. Generally, binary statistical mixtures are considered in which there are two (homogeneous) materials and corresponding coupled equations. The solution process is iterative, but convergence may be slow as either or both materials approach the diffusion and/or atomic mix limits. A three-part acceleration scheme is devised to expedite convergence, particularly in the atomic mix-diffusion limit where computation is extremely slow. The iteration is first divided into a series of 'inner' material and source iterations to attenuate the diffusion and atomic mix error modes separately. Secondly, atomic mix synthetic acceleration is applied to the inner material iteration and S 2 synthetic acceleration to the inner source iterations to offset the cost of doing several inner iterations per outer iteration. Finally, a Krylov iterative solver is wrapped around each iteration, inner and outer, to further expedite convergence. A spectral analysis is conducted and iteration counts and computing cost for the new two-step scheme are compared against those for a simple one-step iteration, to which a Krylov iterative method can also be applied.

ITER CTA newsletter. No. 3

International Nuclear Information System (INIS)

2001-11-01

This ITER CTA newsletter comprises reports of Dr. P. Barnard, Iter Canada Chairman and CEO, about the progress of the first formal ITER negotiations and about the demonstration of details of Canada's bid on ITER workshops, and Dr. V. Vlasenkov, Project Board Secretary, about the meeting of the ITER CTA project board

Progress in licensing ITER in Cadarache

International Nuclear Information System (INIS)

Rodriguez-Rodrigo, Lina; Girard, Jean-Philippe; Uzan-Elbez, Joelle; Marbach, Gabriel; Garin, Pascal; Rosanvallon, Sandrine

2005-01-01

The licensing procedure for ITER in Europe in the framework of the French regulations is a non-prescriptive approach based on a continuous dialogue between the nuclear installation owner (or its representative) and the safety authority. In this paper, the licensing procedure and main safety issues, which are being studied in this process, are presented

ITER council proceedings: 1997

International Nuclear Information System (INIS)

1997-01-01

This volume of the ITER EDA Documentation Series presents records of the 12th ITER Council Meeting, IC-12, which took place on 23-24 July, 1997 in Tampere, Finland. The Council received from the Parties (EU, Japan, Russia, US) positive responses on the Detailed Design Report. The Parties stated their willingness to contribute to fulfil their obligations in contributing to the ITER EDA. The summary discussions among the Parties led to the consensus that in July 1998 the ITER activities should proceed for additional three years with a general intent to enable an efficient start of possible, future ITER construction

Design and evaluation of high-volume fly ash (HVFA) concrete mixes, report D : creep, shrinkage, and abrasion resistance of HVFA concrete.

Science.gov (United States)

2012-10-01

The main objective of this study was to determine the effect on shrinkage, creep, : and abrasion resistance of high-volume fly ash (HVFA) concrete. The HVFA concrete : test program consisted of comparing the shrinkage, creep, and abrasion performance...

Iterative Calibration: A Novel Approach for Calibrating the Molecular Clock Using Complex Geological Events.

Science.gov (United States)

Loeza-Quintana, Tzitziki; Adamowicz, Sarah J

2018-02-01

During the past 50 years, the molecular clock has become one of the main tools for providing a time scale for the history of life. In the era of robust molecular evolutionary analysis, clock calibration is still one of the most basic steps needing attention. When fossil records are limited, well-dated geological events are the main resource for calibration. However, biogeographic calibrations have often been used in a simplistic manner, for example assuming simultaneous vicariant divergence of multiple sister lineages. Here, we propose a novel iterative calibration approach to define the most appropriate calibration date by seeking congruence between the dates assigned to multiple allopatric divergences and the geological history. Exploring patterns of molecular divergence in 16 trans-Bering sister clades of echinoderms, we demonstrate that the iterative calibration is predominantly advantageous when using complex geological or climatological events-such as the opening/reclosure of the Bering Strait-providing a powerful tool for clock dating that can be applied to other biogeographic calibration systems and further taxa. Using Bayesian analysis, we observed that evolutionary rate variability in the COI-5P gene is generally distributed in a clock-like fashion for Northern echinoderms. The results reveal a large range of genetic divergences, consistent with multiple pulses of trans-Bering migrations. A resulting rate of 2.8% pairwise Kimura-2-parameter sequence divergence per million years is suggested for the COI-5P gene in Northern echinoderms. Given that molecular rates may vary across latitudes and taxa, this study provides a new context for dating the evolutionary history of Arctic marine life.

Iterative and iterative-noniterative integral solutions in 3-loop massive QCD calculations

International Nuclear Information System (INIS)

Ablinger, J.; Radu, C.S.; Schneider, C.; Behring, A.; Imamoglu, E.; Van Hoeij, M.; Von Manteuffel, A.; Raab, C.G.

2017-11-01

Various of the single scale quantities in massless and massive QCD up to 3-loop order can be expressed by iterative integrals over certain classes of alphabets, from the harmonic polylogarithms to root-valued alphabets. Examples are the anomalous dimensions to 3-loop order, the massless Wilson coefficients and also different massive operator matrix elements. Starting at 3-loop order, however, also other letters appear in the case of massive operator matrix elements, the so called iterative non-iterative integrals, which are related to solutions based on complete elliptic integrals or any other special function with an integral representation that is definite but not a Volterra-type integral. After outlining the formalism leading to iterative non-iterative integrals,we present examples for both of these cases with the 3-loop anomalous dimension γ (2) qg and the structure of the principle solution in the iterative non-interative case of the 3-loop QCD corrections to the ρ-parameter.

Iterative and iterative-noniterative integral solutions in 3-loop massive QCD calculations

Energy Technology Data Exchange (ETDEWEB)

Ablinger, J.; Radu, C.S.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation (RISC); Behring, A. [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Teilchenphysik und Kosmologie; Bluemlein, J.; Freitas, A. de [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Imamoglu, E.; Van Hoeij, M. [Florida State Univ., Tallahassee, FL (United States). Dept. of Mathematics; Von Manteuffel, A. [Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Raab, C.G. [Johannes Kepler Univ., Linz (Austria). Inst. for Algebra

2017-11-15

Various of the single scale quantities in massless and massive QCD up to 3-loop order can be expressed by iterative integrals over certain classes of alphabets, from the harmonic polylogarithms to root-valued alphabets. Examples are the anomalous dimensions to 3-loop order, the massless Wilson coefficients and also different massive operator matrix elements. Starting at 3-loop order, however, also other letters appear in the case of massive operator matrix elements, the so called iterative non-iterative integrals, which are related to solutions based on complete elliptic integrals or any other special function with an integral representation that is definite but not a Volterra-type integral. After outlining the formalism leading to iterative non-iterative integrals,we present examples for both of these cases with the 3-loop anomalous dimension γ{sup (2)}{sub qg} and the structure of the principle solution in the iterative non-interative case of the 3-loop QCD corrections to the ρ-parameter.

Physics research needs for ITER

International Nuclear Information System (INIS)

Sauthoff, N.R.

1995-01-01

Design of ITER entails the application of physics design tools that have been validated against the world-wide data base of fusion research. In many cases, these tools do not yet exist and must be developed as part of the ITER physics program. ITER's considerable increases in power and size demand significant extrapolations from the current data base; in several cases, new physical effects are projected to dominate the behavior of the ITER plasma. This paper focuses on those design tools and data that have been identified by the ITER team and are not yet available; these needs serve as the basis for the ITER Physics Research Needs, which have been developed jointly by the ITER Physics Expert Groups and the ITER design team. Development of the tools and the supporting data base is an on-going activity that constitutes a significant opportunity for contributions to the ITER program by fusion research programs world-wide

Investigation of Shrinkage Defect in Castings by Quantitative Ishikawa Diagram

Directory of Open Access Journals (Sweden)

Chokkalingam B.

2017-03-01

Full Text Available Metal casting process involves processes such as pattern making, moulding and melting etc. Casting defects occur due to combination of various processes even though efforts are taken to control them. The first step in the defect analysis is to identify the major casting defect among the many casting defects. Then the analysis is to be made to find the root cause of the particular defect. Moreover, it is especially difficult to identify the root causes of the defect. Therefore, a systematic method is required to identify the root cause of the defect among possible causes, consequently specific remedial measures have to be implemented to control them. This paper presents a systematic procedure to identify the root cause of shrinkage defect in an automobile body casting (SG 500/7 and control it by the application of Pareto chart and Ishikawa diagram. with quantitative Weightage. It was found that the root causes were larger volume section in the cope, insufficient feeding of riser and insufficient poured metal in the riser. The necessary remedial measures were taken and castings were reproduced. The shrinkage defect in the castings was completely eliminated.

Recycling of rubble from building demolition for low-shrinkage concretes.

Science.gov (United States)

Corinaldesi, Valeria; Moriconi, Giacomo

2010-04-01

In this project concrete mixtures were prepared that were characterized by low ductility due to desiccation by using debris from building demolition, which after a suitable treatment was used as aggregate for partial replacement of natural aggregates. The recycled aggregate used came from a recycling plant, in which rubble from building demolition was selected, crushed, cleaned, sieved, and graded. Such aggregates are known to be more porous as indicated by the Saturated Surface Dry (SSD) moisture content. The recycled concrete used as aggregates were added to the concrete mixture in order to study their influence on the fresh and hardened concrete properties. They were added either after water pre-soaking or in dry condition, in order to evaluate the influence of moisture in aggregates on the performance of concrete containing recycled aggregate. In particular, the effect of internal curing, due to the use of such aggregates, was studied. Concrete behavior due to desiccation under dehydration was studied by means of both drying shrinkage test and German angle test, through which shrinkage under the restrained condition of early age concrete can be evaluated. Copyright 2009 Elsevier Ltd. All rights reserved.

Specimen Shrinkage and Its Influence on Margin Assessment in Breast Cancer

Directory of Open Access Journals (Sweden)

Badrul H. Yeap

2007-07-01

Conclusion: Breast specimens undergo shrinkage after histological fixation, losing more than a third of their original closest free margin, whilst the tumour itself does not shrink substantially. This phenomenon has vital implications in the accuracy of margin analysis and consequent decisions on further management, including re-operation and the institution of adjuvant radiotherapy.

Meeting of the ITER Council

International Nuclear Information System (INIS)

Drew, M.

2001-01-01

Full text: A meeting of the ITER Council took place in Toronto, Canada, on 27-28 February 2001 (Canada participates in the ITER EDA as an associate of the EU Party). The delegations to the Council were led by Dr. U. Finzi, Principal Advisor in charge of Fusion R and D in the Directorate-General for Research of the European Commission, Mr. T. Sugawa, Deputy Director-General of the Research and Development Bureau of the Ministry of Education, Culture, Sport, Science and Technology of Japan, and Academician E. Velikhov, President of the RRC ''Kurchatov Institute''. The European delegation was joined by Canadian experts including a representative from the Canadian Department of Natural Resources. The Council heard presentations from Dr. H. Kishimoto on the successful completion of the Explorations concerning future joint implementation of ITER, and from Dr. J.-P. Rager on the ITER International Industry Liaison Meeting held in Toronto in November 2000. Having noted statements of Parties' status, in particular concerning the readiness to start negotiations and the progress toward site offers, the Council encouraged the Parties to pursue preparations toward future implementation of ITER along the general lines proposed in the Explorers' final report. The Council also noted the readiness the of the RF and EU Parties to instruct specified current JCT members to remain at their places of assignment after the end of the EDA, in preparation for a transition to the Co-ordinated Technical Activities foreseen as support to ITER negotiations. The Council was pleased to hear that meetings with the Director of the ITER Parties' Designated Safety Representatives had started, and commended the progress toward achieving timely licensing processes with a good common understanding. The Council noted with appreciation the Director's view that no difficulties of principle in the licensing approach had been identified during the informal discussions with the regulatory representatives and

Development of ITER 3D neutronics model and nuclear analyses

International Nuclear Information System (INIS)

Zeng, Q.; Zheng, S.; Lu, L.; Li, Y.; Ding, A.; Hu, H.; Wu, Y.

2007-01-01

ITER nuclear analyses rely on the calculations with the three-dimensional (3D) Monte Carlo code e.g. the widely-used MCNP. However, continuous changes in the design of the components require the 3D neutronics model for nuclear analyses should be updated. Nevertheless, the modeling of a complex geometry with MCNP by hand is a very time-consuming task. It is an efficient way to develop CAD-based interface code for automatic conversion from CAD models to MCNP input files. Based on the latest CAD model and the available interface codes, the two approaches of updating 3D nuetronics model have been discussed by ITER IT (International Team): The first is to start with the existing MCNP model 'Brand' and update it through a combination of direct modification of the MCNP input file and generation of models for some components directly from the CAD data; The second is to start from the full CAD model, make the necessary simplifications, and generate the MCNP model by one of the interface codes. MCAM as an advanced CAD-based MCNP interface code developed by FDS Team in China has been successfully applied to update the ITER 3D neutronics model by adopting the above two approaches. The Brand model has been updated to generate portions of the geometry based on the newest CAD model by MCAM. MCAM has also successfully performed conversion to MCNP neutronics model from a full ITER CAD model which is simplified and issued by ITER IT to benchmark the above interface codes. Based on the two updated 3D neutronics models, the related nuclear analyses are performed. This paper presents the status of ITER 3D modeling by using MCAM and its nuclear analyses, as well as a brief introduction of advanced version of MCAM. (authors)

The construction of geological model using an iterative approach (Step 1 and Step 2)

International Nuclear Information System (INIS)

Matsuoka, Toshiyuki; Kumazaki, Naoki; Saegusa, Hiromitsu; Sasaki, Keiichi; Endo, Yoshinobu; Amano, Kenji

2005-03-01

One of the main goals of the Mizunami Underground Research Laboratory (MIU) Project is to establish appropriate methodologies for reliably investigating and assessing the deep subsurface. This report documents the results of geological modeling of Step 1 and Step 2 using the iterative investigation approach at the site-scale (several 100m to several km in area). For the Step 1 model, existing information (e.g. literature), and results from geological mapping and reflection seismic survey were used. For the Step 2 model, additional information obtained from the geological investigation using existing borehole and the shallow borehole investigation were incorporated. As a result of this study, geological elements that should be represented in the model were defined, and several major faults with trends of NNW, EW and NE trend were identified (or inferred) in the vicinity of the MIU-site. (author)

ITER radio frequency systems

International Nuclear Information System (INIS)

Bosia, G.

1998-01-01

Neutral Beam Injection and RF heating are two of the methods for heating and current drive in ITER. The three ITER RF systems, which have been developed during the EDA, offer several complementary services and are able to fulfil ITER operational requirements

Solving Differential Equations Using Modified Picard Iteration

Science.gov (United States)

Robin, W. A.

2010-01-01

Many classes of differential equations are shown to be open to solution through a method involving a combination of a direct integration approach with suitably modified Picard iterative procedures. The classes of differential equations considered include typical initial value, boundary value and eigenvalue problems arising in physics and…

A linear iterative unfolding method

International Nuclear Information System (INIS)

László, András

2012-01-01

A frequently faced task in experimental physics is to measure the probability distribution of some quantity. Often this quantity to be measured is smeared by a non-ideal detector response or by some physical process. The procedure of removing this smearing effect from the measured distribution is called unfolding, and is a delicate problem in signal processing, due to the well-known numerical ill behavior of this task. Various methods were invented which, given some assumptions on the initial probability distribution, try to regularize the unfolding problem. Most of these methods definitely introduce bias into the estimate of the initial probability distribution. We propose a linear iterative method (motivated by the Neumann series / Landweber iteration known in functional analysis), which has the advantage that no assumptions on the initial probability distribution is needed, and the only regularization parameter is the stopping order of the iteration, which can be used to choose the best compromise between the introduced bias and the propagated statistical and systematic errors. The method is consistent: 'binwise' convergence to the initial probability distribution is proved in absence of measurement errors under a quite general condition on the response function. This condition holds for practical applications such as convolutions, calorimeter response functions, momentum reconstruction response functions based on tracking in magnetic field etc. In presence of measurement errors, explicit formulae for the propagation of the three important error terms is provided: bias error (distance from the unknown to-be-reconstructed initial distribution at a finite iteration order), statistical error, and systematic error. A trade-off between these three error terms can be used to define an optimal iteration stopping criterion, and the errors can be estimated there. We provide a numerical C library for the implementation of the method, which incorporates automatic

An iterative correction approach used to retrieve the refractive index of squid pigment aerosols

Science.gov (United States)

Dinneen, Sean R.; Deravi, Leila F.; Greenslade, Margaret E.

2018-03-01

Pigments localized within cephalopod chromatophores are important for dermal coloration. When isolated and used as materials outside of the animal, the pigments can be processed as aerosols, illustrating a potential application for spray-on-coatings. The optical features of the pigment aerosols are difficult to analyze and require a method to correct for the particle charging and solvent effects accumulated during the aerosolizing process. We describe a method to account for these effects using an innovative iterative approach tied to retrieved refractive index (RI) values. RI retrievals were obtained via the best fit between the corrected, experimentally observed extinction efficiencies compared to those calculated by Mie theory for a specific RI at selected sizes. In addition to these retrievals, the impact of solvent on the particles’ optical properties was also examined via the Maxwell-Garnett mixing rule. Ultimately, we obtained a pigment RI with a real portion (n) of 1.66 (±0.05) representing a lower limit and an imaginary portion (k) of 0.13 (±0.08)i representing an upper limit for the generated aerosols. Combined, this approach advances techniques used to retrieve RI values that benefits both atmospheric chemistry and bio-inspired materials.

Shrinkage stress compensation in composite-restored teeth: relaxation or hygroscopic expansion?

Science.gov (United States)

Meriwether, Laurel A; Blen, Bernard J; Benson, Jarred H; Hatch, Robert H; Tantbirojn, Daranee; Versluis, Antheunis

2013-05-01

Polymerization of composite restorations causes shrinkage, which deforms and thus stresses restored teeth. This shrinkage deformation, however, has been shown to decrease over time. The objective was to investigate whether this reduction was caused by hygroscopic expansion or stress relaxation of the composite/tooth complex. Extracted molars were mounted in rigid stainless steel rings with four spherical reference areas. Twelve molars were prepared with large mesioocclusodistal slots, etched, bonded, and restored with a composite material (Filtek Supreme, 3M ESPE) in two horizontal layers. Ten intact molars were the controls. The teeth were stored either in deionized water or silicone oil. They were scanned after preparation (baseline), restoration (0-week), and after 1, 2, and 4 weeks storage. Scanned tooth surfaces were aligned with the baseline using the unchanged reference areas. Cuspal flexure was calculated from lingual and buccal surface deformation. To verify that the restorations had remained bonded, dye penetration at the interfaces was assessed using basic fuchsin dye. Statistical assessment was done by ANOVA followed by Student-Newman-Keuls post hoc test (p=0.05). Substantial cuspal contraction was found for restored teeth after the composite was cured (13-14 μm cuspal flexure). After 4 weeks cuspal contraction decreased significantly for restored teeth stored in water (7.3 ± 3.2) but not for those stored in silicone oil (11.4 ± 5.0). Dye penetration of the occlusal interface was minimal in both groups (106 ± 87 and 21 ± 28 μm in water and silicone oil, respectively). The results suggest that hygroscopic expansion was the main mechanism for shrinkage stress compensation. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

European technology activities to prepare for ITER component procurement

International Nuclear Information System (INIS)

Gasparotto, M.

2006-01-01

Over the past few years the technology activities of the European fusion programme have principally been devoted to: a) the completion of design and R (and) D studies in preparation for the procurement of ITER systems and components in close collaboration with the ITER team and according to the ITER design and schedule; b) provision of support to European industry and associations in key areas of fusion R (and) D to ensure a competitive and timely approach to the planned procurement. The EU contribution to ITER design and R (and) D activities has been maintained at a significant level with the objectives of: · continuing, and in some areas expanding, the effort in areas where design and R (and)D are still required: in particular in Machine Assembly, Remote Handling, ITER Test Blanket Modules, Diagnostics, Heating and Current Drive Systems. · continuing and completing manufacturing R (and)D to determine the most technically and cost affective manufacturing methods for ITER components to be built in Europe. · preparing new test facilities needed during ITER construction (DIPOLE, HELOKA, DTP-2, ECRH Test Facility, Fatigue Testing Facility). · supporting the European site preparation process and the preparation of safety and licensing documentation for ITER in Cadarache. · maintaining support to EU industries in R (and) D activities of relevance to fusion. To support the ITER Design activities and to prepare for the provision of timely answers to key issues, which may be raised during the ITER design review, support from specialized companies has been set-up in the fields of Civil and General Plant Engineering, Mechanical Engineering / Components, Mechanical Engineering / Systems (and) Plants, Remote Handling (and) Assembly, Electrical Engineering, Nuclear Safety Engineering. In recent years major efforts have been directed towards the technology development of the ITER components for which procurement can be launched during the first years of the construction

Iteration in Early-Elementary Engineering Design

Science.gov (United States)

McFarland Kendall, Amber Leigh

K-12 standards and curricula are beginning to include engineering design as a key practice within Science Technology Engineering and Mathematics (STEM) education. However, there is little research on how the youngest students engage in engineering design within the elementary classroom. This dissertation focuses on iteration as an essential aspect of engineering design, and because research at the college and professional level suggests iteration improves the designer's understanding of problems and the quality of design solutions. My research presents qualitative case studies of students in kindergarten and third-grade as they engage in classroom engineering design challenges which integrate with traditional curricula standards in mathematics, science, and literature. I discuss my results through the lens of activity theory, emphasizing practices, goals, and mediating resources. Through three chapters, I provide insight into how early-elementary students iterate upon their designs by characterizing the ways in which lesson design impacts testing and revision, by analyzing the plan-driven and experimentation-driven approaches that student groups use when solving engineering design challenges, and by investigating how students attend to constraints within the challenge. I connect these findings to teacher practices and curriculum design in order to suggest methods of promoting iteration within open-ended, classroom-based engineering design challenges. This dissertation contributes to the field of engineering education by providing evidence of productive engineering practices in young students and support for the value of engineering design challenges in developing students' participation and agency in these practices.

ITER Construction--Plant System Integration

International Nuclear Information System (INIS)

Tada, E.; Matsuda, S.

2009-01-01

This brief paper introduces how the ITER will be built in the international collaboration. The ITER Organization plays a central role in constructing ITER and leading it into operation. Since most of the ITER components are to be provided in-kind from the member countries, integral project management should be scoped in advance of real work. Those include design, procurement, system assembly, testing, licensing and commissioning of ITER.

ITER definition phase

International Nuclear Information System (INIS)

1989-01-01

The International Thermonuclear Experimental Reactor (ITER) is envisioned as a fusion device which would demonstrate the scientific and technological feasibility of fusion power. As a first step towards achieving this goal, the European Community, Japan, the Soviet Union, and the United States of America have entered into joint conceptual design activities under the auspices of the International Atomic Energy Agency. A brief summary of the Definition Phase of ITER activities is contained in this report. Included in this report are the background, objectives, organization, definition phase activities, and research and development plan of this endeavor in international scientific collaboration. A more extended technical summary is contained in the two-volume report, ''ITER Concept Definition,'' IAEA/ITER/DS/3. 2 figs, 2 tabs

Influence of nano-material on the expansive and shrinkage soil behavior

International Nuclear Information System (INIS)

Taha, Mohd Raihan; Taha, Omer Muhie Eldeen

2012-01-01

This paper presents an experimental study performed on four types of soils mixed with three types of nano-material of different percentages. The expansion and shrinkage tests were conducted to investigate the effect of three type of nano-materials (nano-clay, nano-alumina, and nano-copper) additive on repressing strains in compacted residual soil mixed with different ratios of bentonite (S1 = 0 % bentonite, S2 = 5 % bentonite, S3 = 10 % bentonite, and S4 = 20 % bentonite). The soil specimens were compacted under the condition of maximum dry unit weight and optimum water content (w opt ) using standard compaction test. The physical and mechanical results of the treated samples were determined. The untreated soil values were used as control points for comparison purposes. It was found that with the addition of optimum percentage of nano-material, both the swell strain and shrinkage strain reduced. The results show that nano-material decreases the development of desiccation cracks on the surface of compacted samples without decrease in the hydraulic conductivity.

United States rejoin ITER

International Nuclear Information System (INIS)

Roberts, M.

2003-01-01

Upon pressure from the United States Congress, the US Department of Energy had to withdraw from further American participation in the ITER Engineering Design Activities after the end of its commitment to the EDA in July 1998. In the years since that time, changes have taken place in both the ITER activity and the US fusion community's position on burning plasma physics. Reflecting the interest in the United States in pursuing burning plasma physics, the DOE's Office of Science commissioned three studies as part of its examination of the option of entering the Negotiations on the Agreement on the Establishment of the International Fusion Energy Organization for the Joint Implementation of the ITER Project. These were a National Academy Review Panel Report supporting the burning plasma mission; a Fusion Energy Sciences Advisory Committee (FESAC) report confirming the role of ITER in achieving fusion power production, and The Lehman Review of the ITER project costing and project management processes (for the latter one, see ITER CTA Newsletter, no. 15, December 2002). All three studies have endorsed the US return to the ITER activities. This historical decision was announced by DOE Secretary Abraham during his remarks to employees of the Department's Princeton Plasma Physics Laboratory. The United States will be working with the other Participants in the ITER Negotiations on the Agreement and is preparing to participate in the ITA

Diagnostic integration solutions in the ITER first wall

International Nuclear Information System (INIS)

Martínez, Gonzalo; Martin, Alex; Watts, Christopher; Veshchev, Evgeny; Reichle, Roger; Shigin, Pavel; Sabourin, Flavien; Gicquel, Stefan; Mitteau, Raphael; González, Jorge

2015-01-01

Highlights: • This paper describes the current status of the integration efforts to implement diagnostics in the ITER first wall (FW). • Some diagnostics require a plasma facing element attached to the FW, commonly known as a FW diagnostic. Their design must comply not only with their functional requirements but also with the design of the blankets. • An integrated design concept has been developed. It provides a design that respects the requirements of each system. Thermo-mechanical analyses are on-going to confirm that this configuration respects the heat loads limits on the blanket FW. - Abstract: ITER will have about 50 diagnostic systems for machine protection, plasma control and optimization, and understanding the physics of burning plasma. The implementation in the ITER machine is challenging, particularly for the in-vessel diagnostics, region defined between the vacuum vessel and first wall (FW) contours, where space is constrained by the high number of systems. This paper describes the current status of design integration efforts to implement diagnostics in the ITER first wall. These approaches are the basis for detailed optimization and improvement of conceptual interfaces designs between systems.

Diagnostic integration solutions in the ITER first wall

Energy Technology Data Exchange (ETDEWEB)

Martínez, Gonzalo, E-mail: gonzalo.martinez@iter.org [Technical University of Catalonia (UPC), Barcelona-Tech, Barcelona (Spain); Martin, Alex; Watts, Christopher; Veshchev, Evgeny; Reichle, Roger [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Shigin, Pavel [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); National Research Nuclear University (MEPhI), Kashirskoe shosse, 115409 Moscow (Russian Federation); Sabourin, Flavien [ABMI-Groupe, Parc du Relais BatD 201 Route de SEDS, 13127 Vitrolles (France); Gicquel, Stefan; Mitteau, Raphael [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); González, Jorge [RÜECKER LYPSA, Carretera del Prat, 65, Cornellá de Llobregat (Spain)

2015-10-15

Highlights: • This paper describes the current status of the integration efforts to implement diagnostics in the ITER first wall (FW). • Some diagnostics require a plasma facing element attached to the FW, commonly known as a FW diagnostic. Their design must comply not only with their functional requirements but also with the design of the blankets. • An integrated design concept has been developed. It provides a design that respects the requirements of each system. Thermo-mechanical analyses are on-going to confirm that this configuration respects the heat loads limits on the blanket FW. - Abstract: ITER will have about 50 diagnostic systems for machine protection, plasma control and optimization, and understanding the physics of burning plasma. The implementation in the ITER machine is challenging, particularly for the in-vessel diagnostics, region defined between the vacuum vessel and first wall (FW) contours, where space is constrained by the high number of systems. This paper describes the current status of design integration efforts to implement diagnostics in the ITER first wall. These approaches are the basis for detailed optimization and improvement of conceptual interfaces designs between systems.

ITER towards the construction

International Nuclear Information System (INIS)

Shimomura, Y.

2005-01-01

The ITER Project has been significantly developed in the last few years in preparation for its construction. The ITER Participant's Negotiators have developed the Joint Implementation Agreement (JIA), ready for finalisation following selection of the construction site and nomination of the project's Director General. The ITER International Team and Participant Teams have continued technical and organisational preparations. Construction will be able to start immediately after the international ITER organisation is established, following signature of the JIA. The Project is strongly supported by the governments of the Participants as well as by the scientific community. The real negotiations, including siting and the final details of cost sharing, started in December 2003. The EU, with Cadarache, and Japan, with Rokkasho, have both promised large contributions to the project to strongly support their construction site proposals. Their wish to host ITER construction is too strong to allow convergence to a single site considering the ITER device in isolation. A broader collaboration among the Parties is therefore being contemplated, covering complementary activities to help accelerate fusion development towards a viable power source, and allow the Participants to reach a conclusion on ITER siting. This report reviews these preparations, and the status of negotiations

Iterative Reconstruction Methods for Hybrid Inverse Problems in Impedance Tomography

DEFF Research Database (Denmark)

Hoffmann, Kristoffer; Knudsen, Kim

2014-01-01

For a general formulation of hybrid inverse problems in impedance tomography the Picard and Newton iterative schemes are adapted and four iterative reconstruction algorithms are developed. The general problem formulation includes several existing hybrid imaging modalities such as current density...... impedance imaging, magnetic resonance electrical impedance tomography, and ultrasound modulated electrical impedance tomography, and the unified approach to the reconstruction problem encompasses several algorithms suggested in the literature. The four proposed algorithms are implemented numerically in two...

ITER-FEAT operation

International Nuclear Information System (INIS)

Shimomura, Y.; Huguet, M.; Mizoguchi, T.; Murakami, Y.; Polevoi, A.R.; Shimada, M.; Aymar, R.; Chuyanov, V.A.; Matsumoto, H.

2001-01-01

ITER is planned to be the first fusion experimental reactor in the world operating for research in physics and engineering. The first ten years of operation will be devoted primarily to physics issues at low neutron fluence and the following ten years of operation to engineering testing at higher fluence. ITER can accommodate various plasma configurations and plasma operation modes, such as inductive high Q modes, long pulse hybrid modes and non-inductive steady state modes, with large ranges of plasma current, density, beta and fusion power, and with various heating and current drive methods. This flexibility will provide an advantage for coping with uncertainties in the physics database, in studying burning plasmas, in introducing advanced features and in optimizing the plasma performance for the different programme objectives. Remote sites will be able to participate in the ITER experiment. This concept will provide an advantage not only in operating ITER for 24 hours a day but also in involving the worldwide fusion community and in promoting scientific competition among the ITER Parties. (author)

ITER CTA newsletter. No. 2

International Nuclear Information System (INIS)

2001-10-01

This ITER CTA newsletter contains results of the ITER toroidal field model coil project presented by ITER EU Home Team (Garching) and an article in commemoration of the late Dr. Charles Maisonnier, one of the former leaders of ITER who made significant contributions to its development

An iterative algorithm for fuzzy mixed production planning based on the cumulative membership function

Directory of Open Access Journals (Sweden)

Juan Carlos Figueroa García

2011-12-01

The presented approach uses an iterative algorithm which finds stable solutions to problems with fuzzy parameter sinboth sides of an FLP problem. The algorithm is based on the soft constraints method proposed by Zimmermann combined with an iterative procedure which gets a single optimal solution.

Improved Classification by Non Iterative and Ensemble Classifiers in Motor Fault Diagnosis

Directory of Open Access Journals (Sweden)

PANIGRAHY, P. S.

2018-02-01

Full Text Available Data driven approach for multi-class fault diagnosis of induction motor using MCSA at steady state condition is a complex pattern classification problem. This investigation has exploited the built-in ensemble process of non-iterative classifiers to resolve the most challenging issues in this area, including bearing and stator fault detection. Non-iterative techniques exhibit with an average 15% of increased fault classification accuracy against their iterative counterparts. Particularly RF has shown outstanding performance even at less number of training samples and noisy feature space because of its distributive feature model. The robustness of the results, backed by the experimental verification shows that the non-iterative individual classifiers like RF is the optimum choice in the area of automatic fault diagnosis of induction motor.

LIDAR TS for ITER core plasma. Part II: simultaneous two wavelength LIDAR TS

Science.gov (United States)

Gowers, C.; Nielsen, P.; Salzmann, H.

2017-12-01

We have shown recently, and in more detail at this conference (Salzmann et al) that the LIDAR approach to ITER core TS measurements requires only two mirrors in the inaccessible port plug area of the machine. This leads to simplified and robust alignment, lower risk of mirror damage by plasma contamination and much simpler calibration, compared with the awkward and vulnerable optical geometry of the conventional imaging TS approach, currently under development by ITER. In the present work we have extended the simulation code used previously to include the case of launching two laser pulses, of different wavelengths, simultaneously in LIDAR geometry. The aim of this approach is to broaden the choice of lasers available for the diagnostic. In the simulation code it is assumed that two short duration (300 ps) laser pulses of different wavelengths, from an Nd:YAG laser are launched through the plasma simultaneously. The temperature and density profiles are deduced in the usual way but from the resulting combined scattered signals in the different spectral channels of the single spectrometer. The spectral response and quantum efficiencies of the detectors used in the simulation are taken from catalogue data for commercially available Hamamatsu MCP-PMTs. The response times, gateability and tolerance to stray light levels of this type of photomultiplier have already been demonstrated in the JET LIDAR system and give sufficient spatial resolution to meet the ITER specification. Here we present the new simulation results from the code. They demonstrate that when the detectors are combined with this two laser, LIDAR approach, the full range of the specified ITER core plasma Te and ne can be measured with sufficient accuracy. So, with commercially available detectors and a simple modification of a Nd:YAG laser similar to that currently being used in the design of the conventional ITER core TS design mentioned above, the ITER requirements can be met.

Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER

Energy Technology Data Exchange (ETDEWEB)

Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N. [Institution Project center ITER, Moscow (Russian Federation)

2014-08-21

In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ–ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed.

Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER

Science.gov (United States)

Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N.

2014-08-01

In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ-ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed.

Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER

International Nuclear Information System (INIS)

Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N.

2014-01-01

In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ–ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed

Iterative Reconstruction Techniques in Abdominopelvic CT: Technical Concepts and Clinical Implementation.

Science.gov (United States)

Patino, Manuel; Fuentes, Jorge M; Singh, Sarabjeet; Hahn, Peter F; Sahani, Dushyant V

2015-07-01

This article discusses the clinical challenge of low-radiation-dose examinations, the commonly used approaches for dose optimization, and their effect on image quality. We emphasize practical aspects of the different iterative reconstruction techniques, along with their benefits, pitfalls, and clinical implementation. The widespread use of CT has raised concerns about potential radiation risks, motivating diverse strategies to reduce the radiation dose associated with CT. CT manufacturers have developed alternative reconstruction algorithms intended to improve image quality on dose-optimized CT studies, mainly through noise and artifact reduction. Iterative reconstruction techniques take unique approaches to noise reduction and provide distinct strength levels or settings.

Low baseline and subsequent higher aortic abdominal aneurysm FDG uptake are associated with poor sac shrinkage post endovascular repair

Energy Technology Data Exchange (ETDEWEB)

Marie, Pierre-Yves [CHRU-Nancy, Universite de Lorraine, Nuclear Medecine and Nancyclotep Platform, Nancy (France); INSERM, University of Lorraine, UMR 1116, Nancy (France); CHRU-Nancy, Hopitaux de BRABOIS, Service de Medecine Nucleaire, Vandoeuvre (France); Plissonnier, Didier; Rouer, Martin [CHU-Rouen, Department of Vascular Surgery, Rouen (France); Bravetti, Stephanie [CHRU-Nancy, Universite de Lorraine, Department of Radiology, Nancy (France); Coscas, Raphael [Hopital Ambroise Pare, APHP, Chirurgie Vasculaire, Boulogne-Billancourt (France); Haulon, Stephan [CHU-Lille, Department of Vascular Surgery, Lille (France); Mandry, Damien [CHRU-Nancy, Universite de Lorraine, Department of Radiology, Nancy (France); INSERM, University of Lorraine, UMR 947, Nancy (France); Alsac, Jean-Marc [grid.414093.b, APHP, HEGP, Department of Vascular Surgery, Paris (France); Malikov, Serguei; Settembre, Nicla [CHRU-Nancy, Universite de Lorraine, Vascular Surgery, Nancy (France); Goueffic, Yann [CHU-Nantes, Department of Vascular Surgery, Nantes (France); Morel, Olivier [CHU-Besancon, Department of Nuclear Medecine, Besancon (France); Roch, Veronique [CHRU-Nancy, Universite de Lorraine, Nuclear Medecine and Nancyclotep Platform, Nancy (France); Micard, Emilien [INSERM, University of Lorraine, UMR 947, Nancy (France); INSERM, CHRU-Nancy, Universite de Lorraine, CIC-1433, FCRIN INI-CRCT, Nancy (France); Lamiral, Zohra [INSERM, CHRU-Nancy, Universite de Lorraine, CIC-1433, FCRIN INI-CRCT, Nancy (France); Michel, Jean-Baptiste [INSERM, Bichat, UMR 698, Paris (France); Rossignol, Patrick [INSERM, University of Lorraine, UMR 1116, Nancy (France); INSERM, CHRU-Nancy, Universite de Lorraine, CIC-1433, FCRIN INI-CRCT, Nancy (France)

2018-04-15

The growth phases of medically treated abdominal aortic aneurysms (AAA) are frequently associated with an {sup 18}F-fluorodesoxyglucose positron emission tomography (FDG-PET) pattern involving low baseline and subsequent higher FDG uptake. However, the FDG-PET patterns associated with the endovascular aneurysm repair (EVAR) of larger AAA are presently unknown. This study aimed to investigate the relationship between serial AAA FDG uptake measurements, obtained before EVAR and 1 and 6 months post-intervention and subsequent sac shrinkage at 6 months, a well-recognized indicator of successful repair. Thirty-three AAA patients referred for EVAR (maximal diameter: 55.4 ± 6.0 mm, total volume: 205.7 ± 63.0 mL) underwent FDG-PET/computed tomography (CT) before EVAR and at 1 and 6 months thereafter, with the monitoring of AAA volume and of a maximal standardized FDG uptake [SUVmax] averaged between the axial slices encompassing the AAA. Sac shrinkage was highly variable and could be stratified into three terciles: a first tercile in which shrinkage was absent or very limited (0-29 mL) and a third tercile with pronounced shrinkage (56-165 mL). SUVmax values were relatively low at baseline in the 1st tercile (SUVmax: 1.69 ± 0.33), but markedly increased at 6 months (2.42 ± 0.69, p = 0.02 vs. baseline). These SUV max values were by contrast much higher at baseline in the 3rd tercile (SUVmax: 2.53 ± 0.83 p = 0.009 vs. 1st tercile) and stable at 6 months (2.49 ± 0.80), while intermediate results were documented in the 2nd tercile. Lastly, the amount of sac shrinkage, expressed in absolute values or in percentages of baseline AAA volumes, was positively correlated with baseline SUVmax (p = 0.001 for both). A low pre-EVAR FDG uptake and increased AAA FDG uptake at 6 months are associated with reduced sac shrinkage. This sequential FDG-PET pattern is similar to that already shown to accompany growth phases of medically treated AAA. (orig.)

Low baseline and subsequent higher aortic abdominal aneurysm FDG uptake are associated with poor sac shrinkage post endovascular repair

International Nuclear Information System (INIS)

Marie, Pierre-Yves; Plissonnier, Didier; Rouer, Martin; Bravetti, Stephanie; Coscas, Raphael; Haulon, Stephan; Mandry, Damien; Alsac, Jean-Marc; Malikov, Serguei; Settembre, Nicla; Goueffic, Yann; Morel, Olivier; Roch, Veronique; Micard, Emilien; Lamiral, Zohra; Michel, Jean-Baptiste; Rossignol, Patrick

2018-01-01

The growth phases of medically treated abdominal aortic aneurysms (AAA) are frequently associated with an 18 F-fluorodesoxyglucose positron emission tomography (FDG-PET) pattern involving low baseline and subsequent higher FDG uptake. However, the FDG-PET patterns associated with the endovascular aneurysm repair (EVAR) of larger AAA are presently unknown. This study aimed to investigate the relationship between serial AAA FDG uptake measurements, obtained before EVAR and 1 and 6 months post-intervention and subsequent sac shrinkage at 6 months, a well-recognized indicator of successful repair. Thirty-three AAA patients referred for EVAR (maximal diameter: 55.4 ± 6.0 mm, total volume: 205.7 ± 63.0 mL) underwent FDG-PET/computed tomography (CT) before EVAR and at 1 and 6 months thereafter, with the monitoring of AAA volume and of a maximal standardized FDG uptake [SUVmax] averaged between the axial slices encompassing the AAA. Sac shrinkage was highly variable and could be stratified into three terciles: a first tercile in which shrinkage was absent or very limited (0-29 mL) and a third tercile with pronounced shrinkage (56-165 mL). SUVmax values were relatively low at baseline in the 1st tercile (SUVmax: 1.69 ± 0.33), but markedly increased at 6 months (2.42 ± 0.69, p = 0.02 vs. baseline). These SUV max values were by contrast much higher at baseline in the 3rd tercile (SUVmax: 2.53 ± 0.83 p = 0.009 vs. 1st tercile) and stable at 6 months (2.49 ± 0.80), while intermediate results were documented in the 2nd tercile. Lastly, the amount of sac shrinkage, expressed in absolute values or in percentages of baseline AAA volumes, was positively correlated with baseline SUVmax (p = 0.001 for both). A low pre-EVAR FDG uptake and increased AAA FDG uptake at 6 months are associated with reduced sac shrinkage. This sequential FDG-PET pattern is similar to that already shown to accompany growth phases of medically treated AAA. (orig.)

A block-iterative nodal integral method for forced convection problems

International Nuclear Information System (INIS)

Decker, W.J.; Dorning, J.J.

1992-01-01

A new efficient iterative nodal integral method for the time-dependent two- and three-dimensional incompressible Navier-Stokes equations has been developed. Using the approach introduced by Azmy and Droning to develop nodal mehtods with high accuracy on coarse spatial grids for two-dimensional steady-state problems and extended to coarse two-dimensional space-time grids by Wilson et al. for thermal convection problems, we have developed a new iterative nodal integral method for the time-dependent Navier-Stokes equations for mechanically forced convection. A new, extremely efficient block iterative scheme is employed to invert the Jacobian within each of the Newton-Raphson iterations used to solve the final nonlinear discrete-variable equations. By taking advantage of the special structure of the Jacobian, this scheme greatly reduces memory requirements. The accuracy of the overall method is illustrated by appliying it to the time-dependent version of the classic two-dimensional driven cavity problem of computational fluid dynamics

On the Convergence of Iterative Receiver Algorithms Utilizing Hard Decisions

Directory of Open Access Journals (Sweden)

Jürgen F. Rößler

2009-01-01

Full Text Available The convergence of receivers performing iterative hard decision interference cancellation (IHDIC is analyzed in a general framework for ASK, PSK, and QAM constellations. We first give an overview of IHDIC algorithms known from the literature applied to linear modulation and DS-CDMA-based transmission systems and show the relation to Hopfield neural network theory. It is proven analytically that IHDIC with serial update scheme always converges to a stable state in the estimated values in course of iterations and that IHDIC with parallel update scheme converges to cycles of length 2. Additionally, we visualize the convergence behavior with the aid of convergence charts. Doing so, we give insight into possible errors occurring in IHDIC which turn out to be caused by locked error situations. The derived results can directly be applied to those iterative soft decision interference cancellation (ISDIC receivers whose soft decision functions approach hard decision functions in course of the iterations.

Spirit and prospects of ITER

Energy Technology Data Exchange (ETDEWEB)

Velikhov, E.P. [Kurchatov Institute of Atomic Energy, Moscow (Russian Federation)

2002-10-01

ITER is the unique and the most straightforward way to study the burning plasma science in the nearest future. ITER has a firm physics ground based on the results from the world tokamaks in terms of confinement, stability, heating, current drive, divertor, energetic particle confinement to an extend required in ITER. The flexibility of ITER will allow the exploration of broad operation space of fusion power, beta, pulse length and Q values in various operational scenarios. Success of the engineering R and D programs has demonstrated that all party has an enough capability to produce all the necessary equipment in agreement with the specifications of ITER. The acquired knowledge and technologies in ITER project allow us to demonstrate the scientific and technical feasibility of a fusion reactor. It can be concluded that ITER must be constructed in the nearest future. (author)

Spirit and prospects of ITER

International Nuclear Information System (INIS)

Velikhov, E.P.

2002-01-01

ITER is the unique and the most straightforward way to study the burning plasma science in the nearest future. ITER has a firm physics ground based on the results from the world tokamaks in terms of confinement, stability, heating, current drive, divertor, energetic particle confinement to an extend required in ITER. The flexibility of ITER will allow the exploration of broad operation space of fusion power, beta, pulse length and Q values in various operational scenarios. Success of the engineering R and D programs has demonstrated that all party has an enough capability to produce all the necessary equipment in agreement with the specifications of ITER. The acquired knowledge and technologies in ITER project allow us to demonstrate the scientific and technical feasibility of a fusion reactor. It can be concluded that ITER must be constructed in the nearest future. (author)

ITER interim design report package documents

International Nuclear Information System (INIS)

1996-01-01

This publication contains the Excerpt from the ITER Council (IC-8), the ITER Interim Design Report, Cost Review and Safety Analysis, ITER Site Requirements and ITER Site Design Assumptions and the Excerpt from the ITER Council (IC-9). 8 figs, 2 tabs

ITER CTA newsletter. No. 6

International Nuclear Information System (INIS)

2002-01-01

This ITER CTA Newsletter issue comprises information about the following ITER Meetings: The second negotiation meeting on the joint implementation of ITER, held in Tokyo(Japan) on 22-23 January 2002, and an international ITER symposium on burning plasma science and technology, held the day later after the second negotiation meeting at the same place

Measurement with corrugated tubes of early-age autogenous shrinkage of cement-based material

DEFF Research Database (Denmark)

Tian, Qian; Jensen, Ole Mejlhede

2009-01-01

The use of a special corrugated mould enables transformation of volume strain into horizontal, linear strain measurement in the fluid stage. This allows continuous measurement of the autogenous shrinkage of cement-based materials since casting, and also effectively eliminates unwanted influence...

Improved Image Quality in Head and Neck CT Using a 3D Iterative Approach to Reduce Metal Artifact.

Science.gov (United States)

Wuest, W; May, M S; Brand, M; Bayerl, N; Krauss, A; Uder, M; Lell, M

2015-10-01

Metal artifacts from dental fillings and other devices degrade image quality and may compromise the detection and evaluation of lesions in the oral cavity and oropharynx by CT. The aim of this study was to evaluate the effect of iterative metal artifact reduction on CT of the oral cavity and oropharynx. Data from 50 consecutive patients with metal artifacts from dental hardware were reconstructed with standard filtered back-projection, linear interpolation metal artifact reduction (LIMAR), and iterative metal artifact reduction. The image quality of sections that contained metal was analyzed for the severity of artifacts and diagnostic value. A total of 455 sections (mean ± standard deviation, 9.1 ± 4.1 sections per patient) contained metal and were evaluated with each reconstruction method. Sections without metal were not affected by the algorithms and demonstrated image quality identical to each other. Of these sections, 38% were considered nondiagnostic with filtered back-projection, 31% with LIMAR, and only 7% with iterative metal artifact reduction. Thirty-three percent of the sections had poor image quality with filtered back-projection, 46% with LIMAR, and 10% with iterative metal artifact reduction. Thirteen percent of the sections with filtered back-projection, 17% with LIMAR, and 22% with iterative metal artifact reduction were of moderate image quality, 16% of the sections with filtered back-projection, 5% with LIMAR, and 30% with iterative metal artifact reduction were of good image quality, and 1% of the sections with LIMAR and 31% with iterative metal artifact reduction were of excellent image quality. Iterative metal artifact reduction yields the highest image quality in comparison with filtered back-projection and linear interpolation metal artifact reduction in patients with metal hardware in the head and neck area. © 2015 by American Journal of Neuroradiology.

ITER, a major step toward nuclear fusion energy

International Nuclear Information System (INIS)

Ikeda, K.; Holtkamp, N.; Pick, M.; Gauche, F.; Garin, P.; Bigot, B.; Luciani, J.F.; Mougniot, J.C.; Watteau, J.P.; Saoutic, B.; Becoulet, A.; Libeyre, P.; Beaumont, B.; Simonin, A.; Giancarli, L.; Rosenvallon, S.; Gastaldi, O.; Marbach, G.; Boudot, C.; Ioki, K.; Mitchell, N.; Girard, J.Ph.; Giraud, B.; Lignini, F.; Giguet, E.; Bofusch, E.; Friconneau, J.P.; Di Pace, L.; Pampin, R.; Cook, I.; Maisonnier, D.; Campbell, D.; Hayward, J.; Li Puma, A.; Norajitra, P.; Sardain, P.; Tran, M.Q.; Ward, D.; Moslang, A.; Carre, F.; Serpantie, J.P.

2007-01-01

This document gathers together a series of articles dedicated to ITER. They are organized into 5 parts. The first part describes the potential of fusion as a source of energy that will be able to face the challenge of a continuously increasing demand. After a reminder of the main fusion reactions and the conditions to obtain fusion, the second part focuses on the magnetic fusion based concepts with a special emphasis on the tokamak configuration. In the third part the main components of ITER are described: first the plasma facing components, then the vacuum vessel, the superconducting magnets and the heating systems. In the fourth part short papers concerning ITER safety, the maintenance through remote handling systems, the tritium breeding blanket, are given, along with a full article on the waste management. It is interesting to notice that the nuclear wastes will represent: -) between 1600 and 3800 tons of housekeeping and process wastes produced during the 20 years of operation of ITER (20% very low level waste, 75% low or medium activity with short life and 5% medium activity with long life), -) about 750 tons from component replacement during ITER active operation, and -) about 30000 tons from the decommissioning of ITER. The last part presents the European concepts for a power plant based on a fusion reactor. A basic design is given along with a state of the art of the research on the materials that will be used for the structures. It is highlighted that synergies between fission and fusion technologies exist in at least 4 areas: nuclear design code system, high temperature materials, safety approach, and in-service inspection, maintenance and dismantling. (A.C.)

Progress in standardization for ITER Remote Handling control system

International Nuclear Information System (INIS)

Hamilton, David Thomas; Tesini, Alessandro; Ranz, Roberto; Kozaka, Hiroshi

2014-01-01

Graphical abstract: - Highlights: • Standard parts specified for ITER Remote Handling (RH) control system. • Standard approach for VR modeling of structural deformations in real-time. • RH Core System produced as standard platform for RH controller applications. • Synthetic Viewing investigated and demonstrated. • Structured language defined for RH operation procedures and motion sequences. - Abstract: An integrated control system architecture has been defined for the ITER Remote Handling (RH) equipment systems, and work has been continuing to develop and validate standards for this architecture. Evaluations of standard parts and a standard control room work-cell have contributed to an update of the RH Control System Design Handbook, while R and D activities have been carried out to validate concepts for standard solutions to ITER RH problems: the use of a standard master arm with different slave arms, the achievement of high accuracy tracking of RH operations within virtual reality, and condition monitoring of RH equipment systems. The standardization efforts have been consolidated through the development of a freely distributable software platform to support the adoption of the ITER RH standards. The RH Core System installs on top of the CODAC Core System and provides the basic platform for the development of ITER RH equipment controller applications. The standardization work has continued in the areas of RH viewing, network communication protocols, and a structured language for programming ITER RH operations. Prototyping has been done on high-level control system applications, and R and D has been carried out in the area of synthetic viewing for ITER RH. These developments will be reflected in a new version of the RH Core System to be produced during 2013

Progress in standardization for ITER Remote Handling control system

Energy Technology Data Exchange (ETDEWEB)

Hamilton, David Thomas, E-mail: david.hamilton@iter.org [ITER Organization, Route de Vinon, 13115 St. Paul-lez-Durance (France); Tesini, Alessandro [ITER Organization, Route de Vinon, 13115 St. Paul-lez-Durance (France); Ranz, Roberto [Fusion for Energy, Torres Diagonal Litoral B3, Josep Pla 2, 08019 Barcelona (Spain); Kozaka, Hiroshi [Japan Atomic Energy Agency, Fusion Research and Development Directorate, Naka, Ibaraki-ken 311-0193 (Japan)

2014-10-15

Graphical abstract: - Highlights: • Standard parts specified for ITER Remote Handling (RH) control system. • Standard approach for VR modeling of structural deformations in real-time. • RH Core System produced as standard platform for RH controller applications. • Synthetic Viewing investigated and demonstrated. • Structured language defined for RH operation procedures and motion sequences. - Abstract: An integrated control system architecture has been defined for the ITER Remote Handling (RH) equipment systems, and work has been continuing to develop and validate standards for this architecture. Evaluations of standard parts and a standard control room work-cell have contributed to an update of the RH Control System Design Handbook, while R and D activities have been carried out to validate concepts for standard solutions to ITER RH problems: the use of a standard master arm with different slave arms, the achievement of high accuracy tracking of RH operations within virtual reality, and condition monitoring of RH equipment systems. The standardization efforts have been consolidated through the development of a freely distributable software platform to support the adoption of the ITER RH standards. The RH Core System installs on top of the CODAC Core System and provides the basic platform for the development of ITER RH equipment controller applications. The standardization work has continued in the areas of RH viewing, network communication protocols, and a structured language for programming ITER RH operations. Prototyping has been done on high-level control system applications, and R and D has been carried out in the area of synthetic viewing for ITER RH. These developments will be reflected in a new version of the RH Core System to be produced during 2013.

Clearance potential of ITER vacuum vessel activated materials

International Nuclear Information System (INIS)

Cepraga, D.G.; Cambi, G.; Frisoni, M.

2002-01-01

To demonstrate fusion's environmental attractiveness over the entire life cycle, a waste analysis is mandatory. The clearance is recommended by IAEA for releasing activated solid materials from regulatory control and for waste management policy. The paper focuses on the approach used to support waste analyses for ITER Generic Site Safety Report. The Material Unconditional Clearance Index of all the materials/zones on the equatorial mid-plane of ITER machine have been evaluated, based on IAEA-TECDOC-855. The Bonami-Nitawl-XSDNRPM sequence of the Scale-4.4a code system (using Vitenea-J library) has been firstly used for radiation transport analyses. Then the Anita-2000 code package is used for the activation calculation. The paper presents also, as an example, an application of the clearance indexes estimation for the ITER vacuum vessel materials. The results of the Anita-2000 have been compared with those obtained using the Fispact-99 activation code. (author)

Integration of remote refurbishment performed on ITER components

Energy Technology Data Exchange (ETDEWEB)

Dammann, A., E-mail: alexis.dammann@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Antola, L. [AMEC, 31 Parc du Golf, CS 90519, 13596 Aix en Provence (France); Beaudoin, V. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Dremel, C. [Westinghouse, Electrique France/Astare, 122 Avenue de Hambourg, 13008 Marseille (France); Evrard, D. [SOGETI High Tech, 180 Rue René Descartes, 13851 Aix en Provence (France); Friconneau, J.P. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Lemée, A. [SOGETI High Tech, 180 Rue René Descartes, 13851 Aix en Provence (France); Levesy, B.; Pitcher, C.S. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

2015-10-15

Highlights: • System engineering approach to consolidate requirements to modify the layout of the Hot Cell. • Illustration of the loop between requirement and design. • Verification process. - Abstract: Internal components of the ITER Tokamak are replaced and transferred to the Hot Cell by remote handling equipment. These components include port plugs, cryopumps, divertor cassettes, blanket modules, etc. They are brought to the refurbishment area of the ITER Hot Cell Building for cleaning and maintenance, using remote handling techniques. The ITER refurbishment area will be unique in the world, when considering combination of size, quantity of complex component to refurbish in presence of radiation, activated dust and tritium. The refurbishment process to integrate covers a number of workstations to perform specific remote operations fully covered by a mast on crane system. This paper describes the integration of the Refurbishment Area, explaining the functions, the methodology followed, some illustrations of trade-off and safety improvements.

ITER Status and Plans

Science.gov (United States)

Greenfield, Charles M.

2017-10-01

The US Burning Plasma Organization is pleased to welcome Dr. Bernard Bigot, who will give an update on progress in the ITER Project. Dr. Bigot took over as Director General of the ITER Organization in early 2015 following a distinguished career that included serving as Chairman and CEO of the French Alternative Energies and Atomic Energy Commission and as High Commissioner for ITER in France. During his tenure at ITER the project has moved into high gear, with rapid progress evident on the construction site and preparation of a staged schedule and a research plan leading from where we are today through all the way to full DT operation. In an unprecedented international effort, seven partners ``China, the European Union, India, Japan, Korea, Russia and the United States'' have pooled their financial and scientific resources to build the biggest fusion reactor in history. ITER will open the way to the next step: a demonstration fusion power plant. All DPP attendees are welcome to attend this ITER town meeting.

Report D : self-consolidating concrete (SCC) for infrastructure elements - creep, shrinkage and abrasion resistance.

Science.gov (United States)

2012-08-01

Concrete specimens were fabricated for shrinkage, creep, and abrasion resistance : testing. Variations of self-consolidating concrete (SCC) and conventional concrete were : all tested. The results were compared to previous similar testing programs an...

Rapid alignment of nanotomography data using joint iterative reconstruction and reprojection.

Science.gov (United States)

Gürsoy, Doğa; Hong, Young P; He, Kuan; Hujsak, Karl; Yoo, Seunghwan; Chen, Si; Li, Yue; Ge, Mingyuan; Miller, Lisa M; Chu, Yong S; De Andrade, Vincent; He, Kai; Cossairt, Oliver; Katsaggelos, Aggelos K; Jacobsen, Chris

2017-09-18

As x-ray and electron tomography is pushed further into the nanoscale, the limitations of rotation stages become more apparent, leading to challenges in the alignment of the acquired projection images. Here we present an approach for rapid post-acquisition alignment of these projections to obtain high quality three-dimensional images. Our approach is based on a joint estimation of alignment errors, and the object, using an iterative refinement procedure. With simulated data where we know the alignment error of each projection image, our approach shows a residual alignment error that is a factor of a thousand smaller, and it reaches the same error level in the reconstructed image in less than half the number of iterations. We then show its application to experimental data in x-ray and electron nanotomography.

ITER council proceedings: 1999

International Nuclear Information System (INIS)

1999-01-01

In 1999 the ITER meeting in Cadarache (10-11 March 1999) and the Programme Directors Meeting in Grenoble (28-29 July 1999) took place. Both meetings were exclusively devoted to ITER engineering design activities and their agendas covered all issues important for the development of ITER. This volume presents the documents of these two important meetings

ITER EDA technical activities

International Nuclear Information System (INIS)

Aymar, R.

1998-01-01

Six years of technical work under the ITER EDA Agreement have resulted in a design which constitutes a complete description of the ITER device and of its auxiliary systems and facilities. The ITER Council commented that the Final Design Report provides the first comprehensive design of a fusion reactor based on well established physics and technology

The effect of mold surface topography on plastic parat in-process shrinkage in injection molding

DEFF Research Database (Denmark)

Arlø, Uffe Rolf; Hansen, Hans Nørgaard; Kjær, Erik Michael

2003-01-01

An experimental study of the effect of mold surface roughness on in-process in-flow linear part shrinkage in injection molding has been carried out. The investigation is based on an experimental two-cavity tool, where the cavities have different surface topographies, but are otherwise identical....... The study has been carried out for typical commercial polystyrene and polypropylene grades. The relationship between mold surface topography and linear shrinkage has been investigated with an experimental two-cavity mold producing simple rectangular parts with the nominal dimensions 1 x 25 x 50 mm (see...... figure 1). The cavities have different surface topographies on one side, but are otherwise identical (see discussion of other contribution factors)....

Early age shrinkage pattern of concrete on replacement of fine aggregate with industrial by-product

Directory of Open Access Journals (Sweden)

R.K. Mishra

2016-10-01

Full Text Available This is an experimental work carried out to investigate early age shrinkage pattern of concrete, prepared, on 50% replacement of industrial by-product (like pond ash and granulated blast furnace slag as fine aggregate using OPC, PPC and PSC as a binder. This is to observe the effect of pond ash and slag as they are having some cementitious properties and effect of cement type is also discussed. All the mixes were prepared keeping in view of pumpable concrete without any super plasticizers. Higher shrinkage value indicates the presence of more bleed water or internal moisture. It is concluded that slag is the best option for fine aggregate replacement for concrete making and durable structure.

A fast method to emulate an iterative POCS image reconstruction algorithm.

Science.gov (United States)

Zeng, Gengsheng L

2017-10-01

Iterative image reconstruction algorithms are commonly used to optimize an objective function, especially when the objective function is nonquadratic. Generally speaking, the iterative algorithms are computationally inefficient. This paper presents a fast algorithm that has one backprojection and no forward projection. This paper derives a new method to solve an optimization problem. The nonquadratic constraint, for example, an edge-preserving denoising constraint is implemented as a nonlinear filter. The algorithm is derived based on the POCS (projections onto projections onto convex sets) approach. A windowed FBP (filtered backprojection) algorithm enforces the data fidelity. An iterative procedure, divided into segments, enforces edge-enhancement denoising. Each segment performs nonlinear filtering. The derived iterative algorithm is computationally efficient. It contains only one backprojection and no forward projection. Low-dose CT data are used for algorithm feasibility studies. The nonlinearity is implemented as an edge-enhancing noise-smoothing filter. The patient studies results demonstrate its effectiveness in processing low-dose x ray CT data. This fast algorithm can be used to replace many iterative algorithms. © 2017 American Association of Physicists in Medicine.

Dense Iterative Contextual Pixel Classification using Kriging

DEFF Research Database (Denmark)

Ganz, Melanie; Loog, Marco; Brandt, Sami

2009-01-01

have been proposed to this end, e.g., iterative contextual pixel classification, iterated conditional modes, and other approaches related to Markov random fields. A problem of these methods, however, is their computational complexity, especially when dealing with high-resolution images in which......In medical applications, segmentation has become an ever more important task. One of the competitive schemes to perform such segmentation is by means of pixel classification. Simple pixel-based classification schemes can be improved by incorporating contextual label information. Various methods...... relatively long range interactions may play a role. We propose a new method based on Kriging that makes it possible to include such long range interactions, while keeping the computations manageable when dealing with large medical images....

Future plan of ITER

International Nuclear Information System (INIS)

Kitsunezaki, Akio

1998-01-01

In cooperation of four countries, Japan, USA, EU and Russia, ITER plan has been proceeding as ''the conceptual design activities'' from 1988 to 1990 and ''the industrial design activities'' since 1992. To construct ITER, the legal and work side of ITER operation has been investigated by four countries. However, their economic conditions have been changed to be wrong. So that, construction of ITER can not begin after end of industrial design activities in 1998. Accordingly, they determined to continue the industrial design activities more three years in order to study low cost options and to test the superconductive model·coil. (S.Y.)

A general class of preconditioners for statistical iterative reconstruction of emission computed tomography

International Nuclear Information System (INIS)

Chinn, G.; Huang, S.C.

1997-01-01

A major drawback of statistical iterative image reconstruction for emission computed tomography is its high computational cost. The ill-posed nature of tomography leads to slow convergence for standard gradient-based iterative approaches such as the steepest descent or the conjugate gradient algorithm. In this paper new theory and methods for a class of preconditioners are developed for accelerating the convergence rate of iterative reconstruction. To demonstrate the potential of this class of preconditioners, a preconditioned conjugate gradient (PCG) iterative algorithm for weighted least squares reconstruction (WLS) was formulated for emission tomography. Using simulated positron emission tomography (PET) data of the Hoffman brain phantom, it was shown that the convergence rate of the PCG can reduce the number of iterations of the standard conjugate gradient algorithm by a factor of 2--8 times depending on the convergence criterion

ITER council proceedings: 1992

International Nuclear Information System (INIS)

1994-01-01

At the signing of the ITER EDA Agreement on July, 1992, each of the Parties presented to the Director General the names of their designated members of the ITER Council. Upon receiving those names, the Director General stated that the ITER Engineering Design Activities were ''ready to begin''. The next step in this process was the convening of the first meeting of the ITER Council. The first meeting of the Council, held in Vienna, was opened by Director General Hans Blix. The second meeting was held in Moscow, the formal seat of the Council. This volume presents records of these first two Council meetings and, together with the previous volumes on the text of the Agreement and Protocol 1 and the preparations for their signing respectively, represents essential information on the evolution of the ITER EDA

Polymerization shrinkage of different types of composite resins and microleakage with and without liner in class II cavities.

Science.gov (United States)

Karaman, E; Ozgunaltay, G

2014-01-01

To determine the volumetric polymerization shrinkage of four different types of composite resin and to evaluate microleakage of these materials in class II (MOD) cavities with and without a resin-modified glass ionomer cement (RMGIC) liner, in vitro. One hundred twenty-eight extracted human upper premolar teeth were used. After the teeth were divided into eight groups (n=16), standardized MOD cavities were prepared. Then the teeth were restored with different resin composites (Filtek Supreme XT, Filtek P 60, Filtek Silorane, Filtek Z 250) with and without a RMGIC liner (Vitrebond). The restorations were finished and polished after 24 hours. Following thermocycling, the teeth were immersed in 0.5% basic fuchsin for 24 hours, then midsagitally sectioned in a mesiodistal plane and examined for microleakage using a stereomicroscope. The volumetric polymerization shrinkage of materials was measured using a video imaging device (Acuvol, Bisco, Inc). Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U-tests. All teeth showed microleakage, but placement of RMGIC liner reduced microleakage. No statistically significant differences were found in microleakage between the teeth restored without RMGIC liner (p>0.05). Filtek Silorane showed significantly less volumetric polymerization shrinkage than the methacrylate-based composite resins (pcomposite resin restorations resulted in reduced microleakage. The volumetric polymerization shrinkage was least with the silorane-based composite.

New Ideas for Confined Alpha Diagnostics on ITER

Science.gov (United States)

Fisher, R. K.

2003-10-01

Understanding the dynamics of a burning plasma will require development of adequate alpha particle diagnostics. Three new approaches to obtain information on the confined fast alphas in ITER are proposed. The first technique measures the energetic D and T charge exchange (CX) neutrals that result from the alpha collision-induced knock-on fuel ion tails undergoing electron capture on the MeV D neutral beams planned for heating and current drive. CX neutrals with energies >1 ,MeV would be measured to avoid the background due to the large population of injected beam ions. The second technique measures the energetic knock-on neutron tail due to alphas using the lengths of the proton recoil tracks produced by neutron collisions in the film. The range of the 14 to 18 MeV recoil protons increases by ˜400 microns per MeV. The third approach would measure the CX helium neutrals resulting from confined alphas capturing two electrons in the ablation cloud surrounding a dense gas jet that has been proposed for disruption mitigation in ITER. Jet Charge Exchange (JCX) could allow measurements in the plasma core, while the Pellet Charge Exchange (PCX) technique that provided much of the data on confined alphas in TFTR, will likely be limited by pellet penetration to measurements outside r/ a , ˜ ,0.5 in ITER.

ITER physics design guidelines: 1989

International Nuclear Information System (INIS)

Uckan, N.A.

1990-01-01

The physics basis for ITER has been developed from an assessment of the results of the last twenty-five years of tokamak research and from detailed analysis of important physics issues specifically for the ITER design. This assessment has been carried out with direct participation of members of the experimental teams of each of the major tokamaks in the world fusion program through participation in ITER workshops, contributions to the ITER Physics R and D Program, and by direct contacts between the ITER team and the cognizant experimentalists. Extrapolations to the present data base, where needed, are made in the most cautious way consistent with engineering constraints and performance goals of the ITER. In cases where a working assumptions had to be introduced, which is insufficiently supported by the present data base, is explicitly stated. While a strong emphasis has been placed on the physics credibility of the design, the guidelines also take into account that ITER should be designed to be able to take advantage of potential improvements in tokamak physics that may occur before and during the operation of ITER. (author). 33 refs

ITER council proceedings: 1996

International Nuclear Information System (INIS)

1997-01-01

Records of the 10. ITER Council Meeting (IC-10), held on 26-27 July 1996, in St. Petersburg, Russia, and the 11. ITER Council Meeting (IC-11) held on 17-18 December 1996, in Tokyo, Japan, are presented, giving essential information on the evolution of the ITER Engineering Design Activities (EDA) and the cost review and safety analysis. Figs, tabs

Restrained shrinkage experiments on coated particle fuel compacts in the temperature range 600-1200 deg C

International Nuclear Information System (INIS)

Blackstone, R.; Veringa, H.J.; Loelgen, R.

1976-05-01

Information on irradiation induced creep in reactor graphite and in fuel compact material is an essential ingredient in the design of any reactor core layout, because the creep plasticity of these materials diminishes the stresses which are built up in the fuel element during reactor operation. The restrained shrinkage method in which the shrinkage of a dumbbell shaped creep specimen is restrained by a graphite material which shows less irradiation shrinkage, offers a good possibility of performing a large series of tensile creep experiments in a limited irradiation volume. The irradiations, evaluations and the results of a series of restrained shrinkage experiments in which six different materials were tested, of which five were dummy coated particle compacts and one pure matrix material are described and discussed. These materials were irradiated in the High Flux Reactor of the Euratom Joint Research Centre in Petten/Netherlands. The irradiations were performed in three successive capsules at irradiation temperatures of 600 deg C, 900 deg C, 1050 deg C and 1200 deg C up to a neutron fluence of maximum 3x10 21 n.cm 2 (DNE). The post-irradiation examinations yielded plastic strains up to 2,3%, and values for the radiation creep coefficient were calculated, ranging from 4 to 8.10 -12 at 600 deg C and 8 to 30.10 -12 at 1200 deg C always given per dyn.cm -2 tensile stresses and per 10 20 n.cm -2 fluence units. Generally it was found that the creep behavior of these materials and the temperature dependence of the creep process could be compared with those for normal reactor graphites

Assessment and prediction of drying shrinkage cracking in bonded mortar overlays

Energy Technology Data Exchange (ETDEWEB)

Beushausen, Hans, E-mail: hans.beushausen@uct.ac.za; Chilwesa, Masuzyo

2013-11-15

Restrained drying shrinkage cracking was investigated on composite beams consisting of substrate concrete and bonded mortar overlays, and compared to the performance of the same mortars when subjected to the ring test. Stress development and cracking in the composite specimens were analytically modeled and predicted based on the measurement of relevant time-dependent material properties such as drying shrinkage, elastic modulus, tensile relaxation and tensile strength. Overlay cracking in the composite beams could be very well predicted with the analytical model. The ring test provided a useful qualitative comparison of the cracking performance of the mortars. The duration of curing was found to only have a minor influence on crack development. This was ascribed to the fact that prolonged curing has a beneficial effect on tensile strength at the onset of stress development, but is in the same time not beneficial to the values of tensile relaxation and elastic modulus. -- Highlights: •Parameter study on material characteristics influencing overlay cracking. •Analytical model gives good quantitative indication of overlay cracking. •Ring test presents good qualitative indication of overlay cracking. •Curing duration has little effect on overlay cracking.

Assessment and prediction of drying shrinkage cracking in bonded mortar overlays

International Nuclear Information System (INIS)

Beushausen, Hans; Chilwesa, Masuzyo

2013-01-01

Restrained drying shrinkage cracking was investigated on composite beams consisting of substrate concrete and bonded mortar overlays, and compared to the performance of the same mortars when subjected to the ring test. Stress development and cracking in the composite specimens were analytically modeled and predicted based on the measurement of relevant time-dependent material properties such as drying shrinkage, elastic modulus, tensile relaxation and tensile strength. Overlay cracking in the composite beams could be very well predicted with the analytical model. The ring test provided a useful qualitative comparison of the cracking performance of the mortars. The duration of curing was found to only have a minor influence on crack development. This was ascribed to the fact that prolonged curing has a beneficial effect on tensile strength at the onset of stress development, but is in the same time not beneficial to the values of tensile relaxation and elastic modulus. -- Highlights: •Parameter study on material characteristics influencing overlay cracking. •Analytical model gives good quantitative indication of overlay cracking. •Ring test presents good qualitative indication of overlay cracking. •Curing duration has little effect on overlay cracking

Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber

International Nuclear Information System (INIS)

Li, Zhengqi

2017-01-01

The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa) steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete. [es

Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber

Directory of Open Access Journals (Sweden)

Zhengqi Li

2017-03-01

Full Text Available The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete.

ITER concept definition. V.2

International Nuclear Information System (INIS)

1989-01-01

Volume II of the two volumes describing the concept definition of the International Thermonuclear Experimental Reactor deals with the ITER concept in technical depth, and covers all areas of design of the ITER tokamak. Included are an assessment of the current database for design, scoping studies, rationale for concepts selection, performance flexibility, the ITER concept, the operations and experimental/testing program, ITER parameters and design phase schedule, and research and development specific to ITER. This latter includes a definition of specific research and development tasks, a division of tasks among members, specific milestones, required results, and schedules. Figs and tabs

ITER CTA newsletter. No. 10

International Nuclear Information System (INIS)

2002-07-01

This ITER CTA newsletter issue comprises the ITER backgrounder, which was approved as an official document by the participants in the Negotiations on the ITER Implementation agreement at their fourth meeting, held in Cadarache from 4-6 June 2002, and information about two ITER meetings: one is the third meeting of the ITER parties' designated Safety Representatives, which took place in Cadarache, France from 6-7 June 2002, and the other is the second meeting of the International Tokamak Physics Activity (ITPA) topical group on diagnostics, which was held at General Atomics, San Diego, USA, from 4-8 March 2002

Toward construction of ITER

International Nuclear Information System (INIS)

Shimomura, Yasuo

2005-01-01

The ITER Project has been significantly developed in the past years in preparation for its construction. The ITER Negotiators have developed a draft Joint Implementation Agreement (JIA), ready for completion following the nomination of the Project's Director General (DG). The ITER International Team and Participant Teams have continued technical and organizational preparations. The actual construction will be able to start immediately after the international ITER organization will be established, following signature of the JIA. The Project is now strongly supported by all the participants as well as by the scientific community with the final high-level negotiations, focused on siting and the concluding details of cost sharing, started in December 2003. The EU, with Cadarache, and Japan, with Rokkasho, have both promised large contributions to the project to strongly support their construction site proposals. The extent to which they both wish to host the ITER facility is such that large contributions to a broader collaboration among the Parties are also proposed by them. This covers complementary activities to help accelerate fusion development towards a viable power source, as well as may allow the Participants to reach a conclusion on ITER siting. (author)

ITER tokamak device

International Nuclear Information System (INIS)

Doggett, J.; Salpietro, E.; Shatalov, G.

1991-01-01

The results of the Conceptual Design Activities for the International Thermonuclear Experimental Reactor (ITER) are summarized. These activities, carried out between April 1988 and December 1990, produced a consistent set of technical characteristics and preliminary plans for co-ordinated research and development support of ITER; and a conceptual design, a description of design requirements and a preliminary construction schedule and cost estimate. After a description of the design basis, an overview is given of the tokamak device, its auxiliary systems, facility and maintenance. The interrelation and integration of the various subsystems that form the ITER tokamak concept are discussed. The 16 ITER equatorial port allocations, used for nuclear testing, diagnostics, fuelling, maintenance, and heating and current drive, are given, as well as a layout of the reactor building. Finally, brief descriptions are given of the major ITER sub-systems, i.e., (i) magnet systems (toroidal and poloidal field coils and cryogenic systems), (ii) containment structures (vacuum and cryostat vessels, machine gravity supports, attaching locks, passive loops and active coils), (iii) first wall, (iv) divertor plate (design and materials, performance and lifetime, a.o.), (v) blanket/shield system, (vi) maintenance equipment, (vii) current drive and heating, (viii) fuel cycle system, and (ix) diagnostics. 11 refs, figs and tabs

Improved intact soil-core carbon determination applying regression shrinkage and variable selection techniques to complete spectrum laser-induced breakdown spectroscopy (LIBS).

Science.gov (United States)

Bricklemyer, Ross S; Brown, David J; Turk, Philip J; Clegg, Sam M

2013-10-01

Laser-induced breakdown spectroscopy (LIBS) provides a potential method for rapid, in situ soil C measurement. In previous research on the application of LIBS to intact soil cores, we hypothesized that ultraviolet (UV) spectrum LIBS (200-300 nm) might not provide sufficient elemental information to reliably discriminate between soil organic C (SOC) and inorganic C (IC). In this study, using a custom complete spectrum (245-925 nm) core-scanning LIBS instrument, we analyzed 60 intact soil cores from six wheat fields. Predictive multi-response partial least squares (PLS2) models using full and reduced spectrum LIBS were compared for directly determining soil total C (TC), IC, and SOC. Two regression shrinkage and variable selection approaches, the least absolute shrinkage and selection operator (LASSO) and sparse multivariate regression with covariance estimation (MRCE), were tested for soil C predictions and the identification of wavelengths important for soil C prediction. Using complete spectrum LIBS for PLS2 modeling reduced the calibration standard error of prediction (SEP) 15 and 19% for TC and IC, respectively, compared to UV spectrum LIBS. The LASSO and MRCE approaches provided significantly improved calibration accuracy and reduced SEP 32-55% over UV spectrum PLS2 models. We conclude that (1) complete spectrum LIBS is superior to UV spectrum LIBS for predicting soil C for intact soil cores without pretreatment; (2) LASSO and MRCE approaches provide improved calibration prediction accuracy over PLS2 but require additional testing with increased soil and target analyte diversity; and (3) measurement errors associated with analyzing intact cores (e.g., sample density and surface roughness) require further study and quantification.

CT synthesis in the head & neck region for PET/MR attenuation correction: an iterative multi-atlas approach

Energy Technology Data Exchange (ETDEWEB)

Burgos, Ninon [Translational Imaging Group, Centre for Medical Image Computing, University College London, London (United Kingdom); Cardoso, M Jorge; Modat, Marc [Translational Imaging Group, Centre for Medical Image Computing, University College London, London (United Kingdom); Dementia Research Centre, University College London, London (United Kingdom); Punwani, Shonit [Division of Imaging, University College London Hospitals, London (United Kingdom); Centre for Medical Imaging, University College London, London (United Kingdom); Atkinson, David [Centre for Medical Imaging, University College London, London (United Kingdom); Arridge, Simon R [Centre for Medical Image Computing, University College London, London (United Kingdom); Hutton, Brian F [Institute of Nuclear Medicine, University College London Hospitals, London (United Kingdom); Ourselin, Sébastien [Translational Imaging Group, Centre for Medical Image Computing, University College London, London (United Kingdom); Dementia Research Centre, University College London, London (United Kingdom)

2015-05-18

In this work, we propose to tackle the problem of attenuation correction in the head and neck by synthesising CT from MR images using an iterative multi-atlas approach. The proposed method relies on pre-acquired T2-weighted MRI and CT images of the neck. For each subject, the MRI is non-rigidly mapped to the CT. To synthesise a pseudo CT, all the MRIs in the database are first registered to the target MRI. This registration consists of a robust affine followed by a non-rigid registration. The pseudo CT is obtained by fusing the mapped atlases according to their morphological similarity to the target. In contrast to CTs, T2 images do not provide a good estimate of the bone location. Combining multiple modalities at both the registration and image similarity stages is expected to provide more realistic mappings and to reduce the bias. An initial pseudo CT (pCT) is combined with the target MRI to form a MRI-pCT pair. The MRI-pCT pair is registered to all the MRI-CT pairs from the database. An improved pseudo CT is obtained by fusing the mapped MRI-CT pairs according to their morphological similarity to the target MRI-pCT pair. Results showed that the proposed CT synthesis algorithm based on a multi-atlas information propagation scheme and iterative process is able to synthesise pseudo CT images in a region challenging for registration algorithms. The results also demonstrate that the robust affine decreases the absolute error compared to the classic approach and that the bone refinement process reduces the bias in the bone region. The proposed method could be used to correct for attenuation PET/MR data, but also for dosimetry calculations in the context of MR-based radiotherapy treatment planning.

ITER-EDA physics design requirements and plasma performance assessments

International Nuclear Information System (INIS)

Uckan, N.A.; Galambos, J.; Wesley, J.; Boucher, D.; Perkins, F.; Post, D.; Putvinski, S.

1996-01-01

Physics design guidelines, plasma performance estimates, and sensitivity of performance to changes in physics assumptions are presented for the ITER-EDA Interim Design. The overall ITER device parameters have been derived from the performance goals using physics guidelines based on the physics R ampersand D results. The ITER-EDA design has a single-null divertor configuration (divertor at the bottom) with a nominal plasma current of 21 MA, magnetic field of 5.68 T, major and minor radius of 8.14 m and 2.8 m, and a plasma elongation (at the 95% flux surface) of ∼1.6 that produces a nominal fusion power of ∼1.5 GW for an ignited burn pulse length of ≥1000 s. The assessments have shown that ignition at 1.5 GW of fusion power can be sustained in ITER for 1000 s given present extrapolations of H-mode confinement (τ E = 0.85 x τ ITER93H ), helium exhaust (τ* He /τ E = 10), representative plasma impurities (n Be /n e = 2%), and beta limit [β N = β(%)/(I/aB) ≤ 2.5]. The provision of 100 MW of auxiliary power, necessary to access to H-mode during the approach to ignition, provides for the possibility of driven burn operations at Q = 15. This enables ITER to fulfill its mission of fusion power (∼ 1--1.5 GW) and fluence (∼1 MWa/m 2 ) goals if confinement, impurity levels, or operational (density, beta) limits prove to be less favorable than present projections. The power threshold for H-L transition, confinement uncertainties, and operational limits (Greenwald density limit and beta limit) are potential performance limiting issues. Improvement of the helium exhaust (τ* He /τ E ≤ 5) and potential operation in reverse-shear mode significantly improve ITER performance

The Process of Shrinkage as a Challenge to Urban Governance

Directory of Open Access Journals (Sweden)

Stryjakiewicz Tadeusz

2016-06-01

Full Text Available For many decades most researchers, planners and local authorities have been focusing almost exclusively on urban growth and its socio-economic and spatial consequences. However, in the current debate concerning the future of cities and regions in Europe the process of their shrinkage starts to attract more attention. In the conditions of a declining population, urban governance is an important challenge for local authorities, being usually much more difficult than during the periods of population growth.

Influence of inert fillers on shrinkage cracking of meta-kaolin geo-polymers

International Nuclear Information System (INIS)

Kuenzel, C.; Boccaccini, A.R.

2012-01-01

Geo-polymers contain a network of tetrahedral coordinated aluminate and silicate, and are potential materials to immobilize/encapsulate nuclear wastes. They can exhibit shrinkage cracking when water is removed by drying, and in order to use geo-polymers for waste encapsulation this effect needs to be investigated and controlled. In this study, six different fillers were mixed with meta-kaolin and sodium silicate solution at high pH to form geo-polymers, and the influence of filler addition on mechanical properties has been determined. The fillers used were Fe 2 O 3 , Al 2 O 3 , CaCO 3 , sand, glass and rubber and these do not react during geo-polymerisation reactions. Geo-polymers were prepared containing 30 weight percent of filler. The mechanical properties of the geo-polymers were influenced by the type of filler, with low density fillers increasing mortar viscosity. Geo-polymer samples containing fine filler particles exhibited shrinkage cracking on drying. This was not observed when coarser particles were added and these samples also had significantly improved mechanical properties. (authors)

Creep and drying shrinkage of high performance concrete for the skyway structures of the new San Francisco-Oakland Bay Bridge and cement paste

Science.gov (United States)

2011-03-01

The objective of this study was to determine the influence of admixtures on long term drying shrinkage and creep of high : strength concrete (HSC). Creep and shrinkage of the mix utilized in segments of the Skyway Structure of the San : Francisco-Oak...

Technical basis for the ITER detailed design report, cost review and safety analysis (DDR)

International Nuclear Information System (INIS)

1997-01-01

The ITER Detailed Design Report (DDR), Cost Review and Safety Analysis is the 3rd major milestone representing the progress made in the ITER Engineering Design Activities. With the approval of the Interim Design Report (IDR), it has been possible to freeze the main concepts and system approaches for ITER and to develop the design in more detail for the individual components and sub-systems. This report, although designed to be fully understandable as a separate document, focusses particularly on the main changes since the IDR

Hydro-mechanical coupling in non-saturated medium with phase change. Application to desiccation shrinkage

International Nuclear Information System (INIS)

Lassabatere, Thierry

1994-01-01

The target of this research is to set up a unified and coherent working frame based upon the rigorous principles of thermodynamics and making it possible to model a large class of physical phenomena acting in unsaturated porous media, as well as the related interactions with the mechanical state of the structures. This class corresponds to reactive phenomena among which one finds the phase change (desiccation) for which the whole of its subsequent actions (creep but essentially shrinkage) is modelled and which will be treated as a specific application example. The first chapter recalls the bases of the adopted description of the porous medium as well as the global thermodynamical frame which underlays the whole modelling. Chapter II deals with the mainly new formulation and the identification of a non linear elastic constitutive law of the medium involved. Various reflexion elements related to the microscopic behaviours of the components and to experiments have orientated the model towards some more limitative hypotheses making it possible to have a complete and explicit determination of a law for the macroscopic behaviour. Chapter IV and V are examples of application: chapter IV studies the problem of shrinkage and creep in a coupled linear elastic behaviour. Chapter V is limited to the case of shrinkage treated by a numerical application of the whole non-linear elastic model. The results obtained are in good agreement with the corresponding experiments. (author) [fr

Power converters for ITER

CERN Document Server

Benfatto, I

2006-01-01

The International Thermonuclear Experimental Reactor (ITER) is a thermonuclear fusion experiment designed to provide long deuterium– tritium burning plasma operation. After a short description of ITER objectives, the main design parameters and the construction schedule, the paper describes the electrical characteristics of the French 400 kV grid at Cadarache: the European site proposed for ITER. Moreover, the paper describes the main requirements and features of the power converters designed for the ITER coil and additional heating power supplies, characterized by a total installed power of about 1.8 GVA, modular design with basic units up to 90 MVA continuous duty, dc currents up to 68 kA, and voltages from 1 kV to 1 MV dc.

Influence of vertical holes on creep and shrinkage of railway prestressed concrete sleepers

Science.gov (United States)

Li, Dan; Ngamkhanong, Chayut; Kaewunruen, Sakdirat

2017-09-01

Railway prestressed concrete sleepers (or railroad ties) must successfully perform two critical duties: first, to carry wheel loads from the rails to the ground; and second, to secure rail gauge for dynamic safe movements of trains. The second duty is often fouled by inappropriate design of the time-dependent behaviors due to their creep, shrinkage and elastic shortening responses of the materials. In addition, the concrete sleepers are often modified on construction sites to fit in other systems such as cables, signalling gears, drainage pipes, etc. Accordingly, this study is the world first to investigate creep and shrinkage effects on the railway prestressed concrete sleepers with vertical holes. This paper will highlight constitutive models of concrete materials within the railway sleepers under different environmental conditions over time. It will present a comparative investigation using a variety of methods to evaluate shortening effects in railway prestressed concrete sleepers. The outcome of this study will improve material design, which is very critical to the durability of railway track components.

Minimal volume regulation after shrinkage of red blood cells from five species of reptiles

DEFF Research Database (Denmark)

Kristensen, Karina; Berenbrink, Michael; Koldkjær, Pia

2008-01-01

Red blood cells (RBCs) from most vertebrates restore volume upon hypertonic shrinkage and the mechanisms underlying this regulatory volume increase (RVI) have been studied extensively in these cells. Despite the phylogenetically interesting position of reptiles, very little is known about their red...... cell function. The present study demonstrates that oxygenated RBCs in all major groups of reptiles exhibit no or a very reduced RVI upon ~ 25% calculated hyperosmotic shrinkage. Thus, RBCs from the snakes Crotalus durissus and Python regius, the turtle Trachemys scripta and the alligator Alligator...... was not characterized. It seems, therefore, that the RVI response based on NHE activation was lost among the early sauropsids that gave rise to modern reptiles and birds, while it was retained in mammals. An RVI response has then reappeared in birds, but based on activation of the NKCC. Alternatively, the absence...

Blood velocity estimation using ultrasound and spectral iterative adaptive approaches

DEFF Research Database (Denmark)

Gudmundson, Erik; Jakobsson, Andreas; Jensen, Jørgen Arendt

2011-01-01

-mode images are interleaved with the Doppler emissions. Furthermore, the techniques are shown, using both simplified and more realistic Field II simulations as well as in vivo data, to outperform current state-of-the-art techniques, allowing for accurate estimation of the blood velocity spectrum using only 30......This paper proposes two novel iterative data-adaptive spectral estimation techniques for blood velocity estimation using medical ultrasound scanners. The techniques make no assumption on the sampling pattern of the emissions or the depth samples, allowing for duplex mode transmissions where B...

Distributed Iterative Processing for Interference Channels with Receiver Cooperation

DEFF Research Database (Denmark)

Badiu, Mihai Alin; Manchón, Carles Navarro; Bota, Vasile

2012-01-01

We propose a method for the design and evaluation of distributed iterative algorithms for receiver cooperation in interference-limited wireless systems. Our approach views the processing within and collaboration between receivers as the solution to an inference problem in the probabilistic model...

Effect of Addition of A Marble Dust on Drying Shrinkage Cracks of Cement Mortar Reinforced with Various Fibers

Directory of Open Access Journals (Sweden)

Basim Thabit Al-Khafaji

2017-05-01

Full Text Available This investigation is conducted to study the effect of addition of marble powder (marble dust and different fibers on drying shrinkage cracks and some properties of fibers reinforcment cement mortar. Steel molds having a trapezoidal section, and the end restrained at square shape with( 2.7 meter at length are used to study restrained drying shrinkage of cement mortar. Specimens of ( compressive .flextural. splitting strength were cast. The admixture (marble dust was used to replacie weight of cement with three levels of (4%, 8% and 16% and the fiber hemp and sisal fiber were added for all mixes with proportion by volum of cement . All specimens were cured for (14 days. Average of three results was taken for any test of compressive, tensil and flextural strength. The experimental results showed that the adding of this admixture(marble dust cause adelay in a formation of cracks predicted from a drying shrinkage ,decreases of its width , and hence increases of (compressive, splitting tensil and flextural strength at levels of (4%, and 8%. Thus there is a the positive effect when fiberes added for all mixes of cement mortar with addition of (marble dust. All The admixtures (marble dust and fibers have the obvious visible effect in the delay of the information of shrinkage cracks and the decrease of its width as Compared to the cement mortar mixes when marble dust added a alone.

Iteration and accelerator dynamics

International Nuclear Information System (INIS)

Peggs, S.

1987-10-01

Four examples of iteration in accelerator dynamics are studied in this paper. The first three show how iterations of the simplest maps reproduce most of the significant nonlinear behavior in real accelerators. Each of these examples can be easily reproduced by the reader, at the minimal cost of writing only 20 or 40 lines of code. The fourth example outlines a general way to iteratively solve nonlinear difference equations, analytically or numerically

IHadoop: Asynchronous iterations for MapReduce

KAUST Repository

Elnikety, Eslam Mohamed Ibrahim

2011-11-01

MapReduce is a distributed programming frame-work designed to ease the development of scalable data-intensive applications for large clusters of commodity machines. Most machine learning and data mining applications involve iterative computations over large datasets, such as the Web hyperlink structures and social network graphs. Yet, the MapReduce model does not efficiently support this important class of applications. The architecture of MapReduce, most critically its dataflow techniques and task scheduling, is completely unaware of the nature of iterative applications; tasks are scheduled according to a policy that optimizes the execution for a single iteration which wastes bandwidth, I/O, and CPU cycles when compared with an optimal execution for a consecutive set of iterations. This work presents iHadoop, a modified MapReduce model, and an associated implementation, optimized for iterative computations. The iHadoop model schedules iterations asynchronously. It connects the output of one iteration to the next, allowing both to process their data concurrently. iHadoop\\'s task scheduler exploits inter-iteration data locality by scheduling tasks that exhibit a producer/consumer relation on the same physical machine allowing a fast local data transfer. For those iterative applications that require satisfying certain criteria before termination, iHadoop runs the check concurrently during the execution of the subsequent iteration to further reduce the application\\'s latency. This paper also describes our implementation of the iHadoop model, and evaluates its performance against Hadoop, the widely used open source implementation of MapReduce. Experiments using different data analysis applications over real-world and synthetic datasets show that iHadoop performs better than Hadoop for iterative algorithms, reducing execution time of iterative applications by 25% on average. Furthermore, integrating iHadoop with HaLoop, a variant Hadoop implementation that caches