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Sample records for bondable reinforcement ribbond

  1. Different Clinical Applications of Bondable Reinforcement Ribbond in Pediatric Dentistry

    OpenAIRE

    Tuloglu, Nuray; Bayrak, Sule; Tunc, Emine Sen

    2009-01-01

    Ribbond is a bondable, biocompatible, esthetic, translucent and easy-to-use reinforced ribbon. By virtue of its wide spectrum of intended properties, it enjoys various applications in clinical dentistry. This case report demonstrates usage of Ribbond as a space maintainer, a fixed partial denture with a natural tooth pontic, an endodontic post and cores and a splint material in children. Ribbond can be used as an alternative to conventional treatment in pediatric dentistry.

  2. Use of Polyethylene Fiber (Ribbond) in Pediatric Dentistry

    OpenAIRE

    Eda Arat Maden; Ceyhan Altun

    2012-01-01

    Polyethylene fiber (Ribbond) is a bondable, biocompatible, esthetic, translucent material. By virtue of its wide spectrum of intended properties, it enjoys various applications in clinical dentistry. Different clinical applications of Ribbond include space maintainers, fixed partial dentures with a natural tooth pontic, endodontic posts and cores and splint materials in children. Ribbond can be used as an alternative to conventional treatment in pediatric dentistry. [Arch Clin Exp Surg 2012; ...

  3. Use of Polyethylene Fiber (Ribbond in Pediatric Dentistry

    Directory of Open Access Journals (Sweden)

    Eda Arat Maden

    2012-04-01

    Full Text Available Polyethylene fiber (Ribbond is a bondable, biocompatible, esthetic, translucent material. By virtue of its wide spectrum of intended properties, it enjoys various applications in clinical dentistry. Different clinical applications of Ribbond include space maintainers, fixed partial dentures with a natural tooth pontic, endodontic posts and cores and splint materials in children. Ribbond can be used as an alternative to conventional treatment in pediatric dentistry. [Arch Clin Exp Surg 2012; 1(2.000: 110-115

  4. Treatment of nursing bottle caries with ribbond

    Directory of Open Access Journals (Sweden)

    Ritu Jindal

    2013-01-01

    Full Text Available Ribbond is a biocompatible, esthetic material made from high-strength polyethylene fiber. Lenowoven polyethylene ribbon (Ribbond has been used successfully for tooth splinting, replacement of missing teeth, reinforcement of provisional acrylic resin fixed partial dentures, and orthodontic retention. This article presents the application of this polyethylene ribbon - RIBBOND - for the treatment of nursing bottle caries. To conclude we suggest that this combined technique of polyethylene fibers and composite material could be a very efficient alternative procedure to conventional treatment plans in pedodontic practice, with excellent esthetics and functional results.

  5. A comparative evaluation of fracture resistance of endodontically treated teeth, with variable marginal ridge thicknesses, restored with composite resin and composite resin reinforced with Ribbond: An in vitro study

    Directory of Open Access Journals (Sweden)

    Vaishali Kalburge

    2013-01-01

    Full Text Available Background: The anatomic shape of maxillary premolars show a tendency towards separation of their cusps during mastication after endodontic treatment. Preservation of the marginal ridge of endodontically treated and restored premolars can act as a strengthening factor and improve the fracture resistance. Objectives: To evaluate the effect of varying thickness of marginal ridge on the fracture resistance of endodontically treated maxillary premolars restored with composite and Ribbond reinforced composites. Materials and Methods: One hundred and twenty, freshly extracted, non carious human mature maxillary premolars were selected for this experimental in vitro study. The teeth were randomly assigned in to twelve groups ( n = 10. Group 1 received no preparation. All the premolars in other groups were root canal treated. In subgroups of 3 and 4, DO cavities were prepared while MOD cavities were prepared for all subgroups of group 2, the dimensions of the proximal boxes were kept uniform. In group 3 and 4 the dimensions of the mesial marginal ridge were measured using a digital Vernier caliper as 2 mm, 1.5 mm, 1 mm and 0.5 mm in the respective subgroups. All samples in groups 2.2 and all the subgroups of 3 were restored with a dentin bonding agent and resin composite. The teeth in group 2.3 and all subgroups of 4 were restored with composite reinforced with Ribbond fibers. The premolars were submitted to axial compression up to failure at 45 degree angle to a palatal cusp in universal testing machine. The mean load necessary to fracture was recorded in Newtons and the data was analysed. Results: There was a highly significant difference between mean values of force required to fracture teeth in group 1 and all subgroups of group 2, 3 and 4 (i.e., P < 0.01 Conclusion: On the basis of static loading, preserving the mesial marginal ridge with thicknesses of mm, 1.5 mm, 1 mm and 0.5 mm, composite restored and Ribbond reinforced composite restored

  6. Use of ribbond and panavia F cement in reattaching fractured tooth fragments of vital maxillary anterior teeth

    Directory of Open Access Journals (Sweden)

    Hemalatha Hiremath

    2012-01-01

    Full Text Available Coronal fractures of the anterior teeth are a common form of dental trauma that mainly affects children and adolescents. One of the options for managing coronal tooth fractures when the tooth fragment is available and there is no or minimal violation of the biological width is the reattachment of the fragment. This article presents a novel technique for reattachment of oblique fractured fragment of vital maxillary central and lateral incisor with pulp exposure. Pulp capping was done using mineral trioxide aggregate. Orthodontic extrusion was done to expose the sub gingival fractured site. Polyethylene fiber (ribbond and panavia F cement were used to reattach the fractured fragment using an internal groove technique to provide high fracture strength to restored tooth. Ribbond fibers can be used to give additional strength to the reattached tooth fragment so that the tooth obtains fracture resistance equal to an intact tooth.

  7. The Effect of Glass and Polyethylene Fiber Reinforcement on Flexural Strength of Provisional Restorative Resins: An In Vitro Study

    OpenAIRE

    Natarajan, Parthasarathy; Thulasingam, C.

    2012-01-01

    The aim is to evaluate and compare the flexural strength of different provisional restorative materials reinforced with glass and polyethylene fibers. A total of 90 samples were prepared and divided into three groups based on the type of fiber reinforcement, unidirectional S-glass (Splint-It) and ultra-molecular weight polyethylene (Ribbond). Unreinforced samples served as control group. Again each group was subdivided into three subgroups based on type of provisional restorative resins, heat...

  8. Plasma Sprayed Bondable Stainless Surface (BOSS) Coatings for Corrosion Protection and Adhesion Treatments

    Science.gov (United States)

    Davis, G. D.; Groff, G. B.; Rooney, M.; Cooke, A. V.; Boothe, R.

    1995-01-01

    Plasma-sprayed Bondable Stainless Surface (BOSS) coatings are being developed under the Solid Propulsion Integrity Program's (SPIP) Bondlines Package. These coatings are designed as a steel case preparation treatment prior to insulation lay-up. Other uses include the exterior of steel cases and bonding surfaces of nozzle components. They provide excellent bondability - rubber insulation and epoxy bonds fail cohesively within the polymer - for both fresh surfaces and surfaces having undergone natural and accelerated environmental aging. They have passed the MSFC requirements for protection of inland and sea coast environment. Because BOSS coatings are inherently corrosion resistant, they do not require preservation by greases or oils. The reduction/elimination of greases and oils, known bondline degraders, can increase SRM reliability, decrease costs by reducing the number of process steps, and decrease environmental pollution by reducing the amount of methyl chloroform used for degreasing and thus reduce release of the ozone-depleting chemical in accordance with the Clean Air Act and the Montreal Protocol. The coatings can potential extend the life of RSRM case segments and nozzle components by eliminating erosion due to multiple grit blasting during each use cycle and corrosion damage during marine recovery. Concurrent work for the Air Force show that other BOSS coatings give excellent bondline strength and durability for high-performance structures of aluminum and titanium.

  9. Microstructure changes in nanoparticulate gold films under different thermal atmospheres and the effects on bondability

    International Nuclear Information System (INIS)

    Sintering in a furnace under different thermal atmospheres of air, nitrogen (N2) or N2 bubbled through formic acid (FA/N2) was carried out for a spin-coated gold nanoparticle (NP) ink. Temperatures of 200, 250 and 290 deg. C were applied for each atmosphere. The size of the NPs was measured by transmission electron microscopy and the decomposition temperatures of the solvent and the organic capping molecules of the ink were determined by thermo-gravimetric analysis. The changes in the microstructure of Au NP films after sintering were studied using the field emission scanning electron microscopy, X-ray diffractometry, atomic force microscopy and focused ion beam analysis. Organic residues remaining on the film were detected by Fourier transform infrared spectroscopy and sheet resistance was measured using a four point probe for the calculation of resistivity. Wire bonding tests on the Au film were performed for bondability. The Au NP films sintered under air showed neck growth as temperature increased, while the films sintered under N2 showed grain growth, except for the film sintered at 290 deg. C. Coalescence and grain growth as well as porosity were observed in the film sintered under FA/N2. The infrared absorption peaks of stretch and deformation were found as organic residues, with C-O stretch peak only being detected in the film sintered under FA/N2. All of the samples represented a preferred Au (1 1 1) orientation. The film sintered under N2 showed good quality compared with those sintered under air or FA/N2 and the resistivity was about twice the bulk value. Wire bonding tests were successful in all the films sintered under air, N2 or FA/N2 atmospheres.

  10. Degradation behaviour of fiber reinforced plastic under electron beam irradiation

    International Nuclear Information System (INIS)

    Various mechanical properties of four kinds of glass fiber-reinforced plastics irradiated with electron beams were examined at three temperatures; room temperature, 123 K and 77 K. Dynamic viscoelastic properties were measured, and fractography by means of scanning electron microscopy was observed in order to clarify degradation behaviour. A considerable decrease in interlaminar shear strength (ILSS) at room temperature was observed above 60 MGy. On the other hand, the three-point bending strength at 77 K and the ILSS at 123 K decreased with increasing irradiation. Fractography reveals that the degradation of the interface layer between matrix resin and fiber plays an important role in the strength reduction at 123 K and 77 K. These findings suggest that the interface between matrix resin and fiber loses its bondability at 123 K arid 77 K after electron beam irradiation. (author)

  11. Anchor reinforcements

    Energy Technology Data Exchange (ETDEWEB)

    Levkovich, P.Ye.; Sal' nikov, V.K.; Savich, N.S.

    1980-11-30

    An anchor reinforcement includes an anchor shaft, an elastic jig with a separator wall having compartments placed parallely along it and filled with reinforcement material and a device for destroying the jig wall separator. To quickly put the anchor in place and increase the reliability of the reinforcement by mixing the reinforcement material components better, the device for destroying the jig separator wall was made in the shape of a shovel, fastened to the anchor shaft and the separator wall has a longitudinal hollow for holding the anchor shaft/shovel.

  12. Application of cold plasma technology in fiber-reinforced composite materials

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A study is presented concerning a cold plasma technique for improving the bondability of highstrength high-modulus multi-filament polyethylene fibers to polymer matrices and the fibers impregnation with the objective to fabricate composite materials (CMs). Strong bonding between the matrixes and reinforcing fibers during the production of composites appears in the case if interaction is chemical. The value of the activation energy of the chemical interaction for very high performance polyethylene fiber was estimated. It was 1.14 eV. This allows using the cold plasma technique for producing CMs. In order to understand the effect of cold plasma treatment treated and untreated fibers were used to fabricate CMs. The strong bond between the matrix and plasma-activated fibers affects both the properties and failure mode of composite. The properties and failure modes were compared to those of CMs reinforced with untreated fibers. After plasma treatment the properties of CMs are increased. CMs are broken as a unit whole under tension. The ideas of the activating the fibers by cold plasma treatment above the activation energy of the chemical interaction may be extended over other types of the fibers and matrices to produce new types of fiber-reinforced composite materials with high physicomechanical indices.

  13. Adherence of Streptococcus mutans to Fiber-Reinforced Filling Composite and Conventional Restorative Materials.

    Science.gov (United States)

    Lassila, Lippo V J; Garoushi, Sufyan; Tanner, Johanna; Vallittu, Pekka K; Söderling, Eva

    2009-01-01

    OBJECTIVES.: The aim was to investigate the adhesion of Streptococcus mutans (S. mutans) to a short glass fibers reinforced semi-IPN polymer matrix composite resin. The effect of surface roughness on adhesion was also studied. For comparison, different commercial restorative materials were also evaluated. MATERIALS AND METHODS.: Experimental composite FC resin was prepared by mixing 22.5 wt% of short E-glass fibers, 22.5 wt% of IPN-resin and 55 wt% of silane treated silica fillers using high speed mixing machine. Three direct composite resins (Z250, Grandio and Nulite), resin-modified glass ionomers (Fuji II LC), amalgam (ANA 2000), fiber-reinforced composite (FRC) (everStick and Ribbond), and pre-fabricated ceramic filling insert (Cerana class 1) were tested in this study. Enamel and dentin were used as controls. The specimens (n=3/group) with or without saliva were incubated in a suspension of S. mutans allowing initial adhesion to occur. For the enumeration of cells on the disc surfaces as colony forming units (CFU) the vials with the microbe samples were thoroughly Vortex-treated and after serial dilutions grown anaerobically for 2 days at +37 degrees C on Mitis salivarius agars (Difco) containing bacitracin. Bacterial adhesion was also evaluated by using scanning electron microscopy. Surface roughness (Ra) of the materials was also determined using a surface profilometer. All results were statistically analyzed with one-way analysis of variance (ANOVA). RESULTS.: Composite FC resin and other commercial restorative materials showed similar adhesion of S. mutans, while adhesion to dentin and enamel was significantly higher (p<0.05). Surface roughness had no effect on bacterial adhesion. Saliva coating significantly decreased the adhesion for all materials (p<0.05). Composite FC resin had a significantly higher Ra value than control groups (p<0.05). CONCLUSIONS.: Short fiber-reinforced composite with semi-IPN polymer matrix revealed similar S. mutans adhesion

  14. REINFORCED COMPOSITE PANEL

    DEFF Research Database (Denmark)

    2003-01-01

    A composite panel having front and back faces, the panel comprising facing reinforcement, backing reinforcement and matrix material binding to the facing and backing reinforcements, the facing and backing reinforcements each independently comprising one or more reinforcing sheets, the facing...... matrix material, the facing and backing reinforcements being interconnected to resist out-of-plane relative movement. The reinforced composite panel is useful as a barrier element for shielding structures, equipment and personnel from blast and/or ballistic impact damage....

  15. Basal Reinforced Piled Embankments

    NARCIS (Netherlands)

    Van Eekelen, S.J.M.

    2015-01-01

    A basal reinforced piled embankment consists of a reinforced embankment on a pile foundation. The reinforcement consists of one or more horizontal layers of geosynthetic reinforcement (GR) installed at the base of the embankment. The design of the GR is the subject of this thesis. A basal reinforce

  16. Habituation of reinforcer effectiveness

    OpenAIRE

    Lloyd, David R; Hawk, Larry W.

    2014-01-01

    In this paper we propose an integrative model of habituation of reinforcer effectiveness (HRE) that links behavioral and neural based explanations of reinforcement. We argue that habituation of reinforcer effectiveness (HRE) is a fundamental property of reinforcing stimuli. Most reinforcement models implicitly suggest that the effectiveness of a reinforcer is stable across repeated presentations. In contrast, an HRE approach predicts decreased effectiveness due to repeated presentation. We ar...

  17. Transverse Reinforcement in Reinforced Concrete Columns

    Science.gov (United States)

    Gramblička, Štefan; Veróny, Peter

    2013-11-01

    In the article we are dealing with the influence of transverse reinforcement to the resistance of a cross-section of the reinforced concrete columns and also with the effective detailing of the column reinforcement. We are verifying the correctness of design guides for detailing of transverse reinforcement. We are also taking into account the diameter of stirrups and its influence over transverse deformation of column.

  18. The effect of glass and polyethylene fiber reinforcement on flexural strength of provisional restorative resins: an in vitro study.

    Science.gov (United States)

    Natarajan, Parthasarathy; Thulasingam, C

    2013-12-01

    The aim is to evaluate and compare the flexural strength of different provisional restorative materials reinforced with glass and polyethylene fibers. A total of 90 samples were prepared and divided into three groups based on the type of fiber reinforcement, unidirectional S-glass (Splint-It) and ultra-molecular weight polyethylene (Ribbond). Unreinforced samples served as control group. Again each group was subdivided into three subgroups based on type of provisional restorative resins, heats cure polymethyl methacrylate, self-cure poly methyl methacrylate and self-cure bis-acryl composite. Samples were loaded in a universal testing machine until fracture occurs. The mean flexural strengths (MPa) were subjected to the one-way ANOVA, followed by the Tukey-HSD test at a significance level of 0.001. The result shows all the fiber reinforced samples possessed greater strength than the control samples. In control samples, the heat cure poly methyl methacrylate resin (72.74 ± 2.28 MPa) had the greatest flexural strength, followed by self-cure bis-acryl composite (67.05 ± 2.35 MPa) and self-cure poly methyl methacrylate resin (52.88 ± 1.90 MPa). In both heat and self-cure poly methyl methacrylate resin, the polyethylene fiber reinforcement (96.00 ± 2.63 MPa, 86.17 ± 1.92 MPa) provides the greatest strength than glass fiber reinforcement (92.68 ± 1.58 MPa, 76.40 ± 2.11 MPa). In self-cure bis-acryl composite, the glass fiber (105.95 ± 3.07 MPa) shows better reinforcement than polyethylene fiber (99.41 ± 1.74 MPa).The fibers reinforcement increases the flexural strength of provisional restorative resins. PMID:24431771

  19. Studies on radiation resistance of fiber reinforced plastic composites featured by easiness of manufacturing, 2

    International Nuclear Information System (INIS)

    Various mechanical properties were examined at room temperature and at 123 or 77 K on five kinds of glass fiber reinforced plastics (GFRP) irradiated with electron beams. Dynamic viscoelastic properties and fractography by means of scanning electron microscopy (SEM) were also measured in order to clarify degradation behavior. Considerable decrease in interlaminar shear strength (ILSS) at room temperature was observed above the absorbed dose of 60 MGy, while three-point bending strength showed no change even up to 100 MGy. On the other hand, the three-point bending strength and the ILSS at 123 K or 77 K strikingly decreased with increasing absorbed dose. The fractography reveals that debonding of glass fiber and matrix resin or the degradation of silane coupling agents plays an important role in the strength reduction at low temperature. These findings suggest that the interface between matrix and fiber loses its bondability at low temperature after electron beam irradiation, although high bond strength still remeins at room temperature. (author)

  20. Shear Reinforcements in the Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Moayyad M. Al-Nasra

    2013-10-01

    Full Text Available - This study focuses on the use of different types of shear reinforcement in the reinforced concrete beams. Four different types of shear reinforcement are investigated; traditional stirrups, welded swimmer bars, bolted swimmer bars, and u-link bolted swimmer bars. Beam shear strength as well as beam deflection are the main two factors considered in this study. Shear failure in reinforced concrete beams is one of the most undesirable modes of failure due to its rapid progression. This sudden type of failure made it necessary to explore more effective ways to design these beams for shear. The reinforced concrete beams show different behavior at the failure stage in shear compare to the bending, which is considered to be unsafe mode of failure. The diagonal cracks that develop due to excess shear forces are considerably wider than the flexural cracks. The cost and safety of shear reinforcement in reinforced concrete beams led to the study of other alternatives. Swimmer bar system is a new type of shear reinforcement. It is a small inclined bars, with its both ends bent horizontally for a short distance and welded or bolted to both top and bottom flexural steel reinforcement. Regardless of the number of swimmer bars used in each inclined plane, the swimmer bars form plane-crack interceptor system instead of bar-crack interceptor system when stirrups are used. Several reinforced concrete beams were carefully prepared and tested in the lab. The results of these tests will be presented and discussed. The deflection of each beam is also measured at incrementally increased applied load.

  1. Management of Reinforcement Corrosion

    DEFF Research Database (Denmark)

    Küter, André; Geiker, Mette Rica; Møller, Per

    Reinforcement corrosion is the most important cause for deterioration of reinforced concrete structures, both with regard to costs and consequences. Thermodynamically consistent descriptions of corrosion mechanisms are expected to allow the development of innovative concepts for the management of...... reinforcement corrosion....

  2. Habituation of reinforcer effectiveness

    Directory of Open Access Journals (Sweden)

    David R Lloyd

    2014-01-01

    Full Text Available In this paper we propose an integrative model of habituation of reinforcer effectiveness (HRE that links behavioral and neural based explanations of reinforcement. We argue that habituation of reinforcer effectiveness (HRE is a fundamental property of reinforcing stimuli. Most reinforcement models implicitly suggest that the effectiveness of a reinforcer is stable across repeated presentations. In contrast, an HRE approach predicts decreased effectiveness due to repeated presentation. We argue that repeated presentation of reinforcing stimuli decreases their effectiveness and that these decreases are described by the behavioral characteristics of habituation (McSweeney and Murphy, 2009;Rankin et al., 2009. We describe a neural model that postulates a positive association between dopamine neurotransmission and HRE. We present evidence that stimulant drugs, which artificially increase dopamine neurotransmission, disrupt (slow normally occurring HRE and also provide evidence that stimulant drugs have differential effects on operant responding maintained by reinforcers with rapid vs. slow HRE rates. We hypothesize that abnormal HRE due to genetic and/or environmental factors may underlie some behavioral disorders. For example, recent research indicates that slow-HRE is predictive of obesity. In contrast ADHD may reflect ‘accelerated-HRE’. Consideration of HRE is important for the development of effective reinforcement based treatments. Finally, we point out that most of the reinforcing stimuli that regulate daily behavior are non-consumable environmental/social reinforcers which have rapid-HRE. The almost exclusive use of consumable reinforcers with slow-HRE in pre-clinical studies with animals may have caused the importance of HRE to be overlooked. Further study of reinforcing stimuli with rapid-HRE is needed in order to understand how habituation and reinforcement interact and regulate behavior.

  3. Endodontic and prosthetic treatment of teeth with periapical lesions in a 16-year-old-girl

    Directory of Open Access Journals (Sweden)

    Buket Ayna

    2010-04-01

    Full Text Available This paper reports the nonsurgical endodontic therapy using calcium hydroxide intracanal dressing and prosthetic treatment of 9 teeth with periapical lesions in a 16-year-old female patient. The periodontal treatment plan included oral hygiene instructions, mechanical debridement and gingivectomy in the maxillary incisors to improve gingival contouring. Root canal treatment was indicated for teeth 11-13, 21, 22, 42-45. After successive changes of a calcium hydroxide intracanal dressing during 6 weeks, the size of the periapical radiolucencies decreased and lesion remission occurred after root canal obturation. The endodontically treated teeth received a bondable polyethylene reinforcement fiber (Ribbond in the prepared canal space and crown buildup was done with composite resin. Prosthetic rehabilitation was planned with single-unit metal-ceramic crowns and fixed partial dentures. Clinical and radiographic evaluation after 6 months showed successful results. The outcomes of this case showed that chronic periapical lesions can respond favorably to nonsurgical endodontic treatment in adolescent patients and that, with proper indication, polyethylene fibers can provide an effective conservative and esthetic option for reinforcing endodontically treated teeth undergoing prosthetic rehabilitation.

  4. Choice and multiple reinforcers

    OpenAIRE

    Moore, Jay

    1982-01-01

    Pigeons chose between equivalent two-component mixed and multiple terminal-link schedules of reinforcement in the concurrent-chains procedure. The pigeons preferred the multiple schedule over the mixed when the components of the compound schedules were differentiated in terms of density of reinforcement, but the pigeons were indifferent when the components were differentiated in terms of number of reinforcers per cycle. Taken together, these results indicate that a local variable, the interva...

  5. Continuous Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1996-01-01

    This report deals with stress and stiffness estimates of continuous reinforced concrete beams with different stiffnesses for negative and positive moments e.g. corresponding to different reinforcement areas in top and bottom. Such conditions are often met in practice.The moment distribution at the...

  6. Composite Intersection Reinforcement

    Science.gov (United States)

    Misciagna, David T. (Inventor); Fuhrer, Jessica J. (Inventor); Funk, Robert S. (Inventor); Tolotta, William S. (Inventor)

    2013-01-01

    An assembly and method for manufacturing a composite reinforcement for unitizing a structure are provided. According to one embodiment, the assembly includes a base having a plurality of pins extending outwardly therefrom to define a structure about which a composite fiber is wound to define a composite reinforcement preform. The assembly also includes a plurality of mandrels positioned adjacent to the base and at least a portion of the composite reinforcement preform, and a cap that is positioned over at least a portion of the plurality of mandrels. The cap is configured to engage each of the mandrels to support the mandrels and the composite reinforcement preform during a curing process to form the composite reinforcement.

  7. Algorithms for Reinforcement Learning

    CERN Document Server

    Szepesvari, Csaba

    2010-01-01

    Reinforcement learning is a learning paradigm concerned with learning to control a system so as to maximize a numerical performance measure that expresses a long-term objective. What distinguishes reinforcement learning from supervised learning is that only partial feedback is given to the learner about the learner's predictions. Further, the predictions may have long term effects through influencing the future state of the controlled system. Thus, time plays a special role. The goal in reinforcement learning is to develop efficient learning algorithms, as well as to understand the algorithms'

  8. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...... beam is \\SI{4\\times10}{mm}. It is reinforced with a \\SI{3}{mm} high steel band covering the full width of the beam. The experimental setup is described and results for this beam are presented. Furthermore, the results for three similar experiments with a \\SI{6}{mm} steel band reinforcement are briefly...

  9. Reinforcement learning an introduction

    CERN Document Server

    Sutton, Richard S

    1998-01-01

    Richard Sutton and Andrew Barto provide a clear and simple account of the key ideas and algorithms of reinforcement learning. Their discussion ranges from the history of the field's intellectual foundations to the most recent developments and applications.

  10. Choice and conditioned reinforcement.

    OpenAIRE

    Fantino, E; Freed, D; Preston, R. A.; Williams, W A

    1991-01-01

    A potential weakness of one formulation of delay-reduction theory is its failure to include a term for rate of conditioned reinforcement, that is, the rate at which the terminal-link stimuli occur in concurrent-chains schedules. The present studies assessed whether or not rate of conditioned reinforcement has an independent effect upon choice. Pigeons responded on either modified concurrent-chains schedules or on comparable concurrent-tandem schedules. The initial link was shortened on only o...

  11. Reinforcement Learning: A Survey

    OpenAIRE

    Kaelbling, L. P.; Littman, M. L.; Moore, A. W.

    1996-01-01

    This paper surveys the field of reinforcement learning from a computer-science perspective. It is written to be accessible to researchers familiar with machine learning. Both the historical basis of the field and a broad selection of current work are summarized. Reinforcement learning is the problem faced by an agent that learns behavior through trial-and-error interactions with a dynamic environment. The work described here has a resemblance to work in psychology, but differs considerably in...

  12. Reinforcement learning in scheduling

    Science.gov (United States)

    Dietterich, Tom G.; Ok, Dokyeong; Zhang, Wei; Tadepalli, Prasad

    1994-01-01

    The goal of this research is to apply reinforcement learning methods to real-world problems like scheduling. In this preliminary paper, we show that learning to solve scheduling problems such as the Space Shuttle Payload Processing and the Automatic Guided Vehicle (AGV) scheduling can be usefully studied in the reinforcement learning framework. We discuss some of the special challenges posed by the scheduling domain to these methods and propose some possible solutions we plan to implement.

  13. The substitutability of reinforcers.

    Science.gov (United States)

    Green, Leonard; Freed, Debra E

    1993-07-01

    Substitutability is a construct borrowed from microeconomics that describes a continuum of possible interactions among the reinforcers in a given situation. Highly substitutable reinforcers, which occupy one end of the continuum, are readily traded for each other due to their functional similarity. Complementary reinforcers, at the other end of the continuum, tend to be consumed jointly in fairly rigid proportion, and therefore cannot be traded for one another except to achieve that proportion. At the center of the continuum are reinforcers that are independent with respect to each other; consumption of one has no influence on consumption of another. Psychological research and analyses in terms of substitutability employ standard operant conditioning paradigms in which humans and nonhumans choose between alternative reinforcers. The range of reinforcer interactions found in these studies is more readily accommodated and predicted when behavior-analytic models of choice consider issues of substitutability. New insights are gained into such areas as eating and drinking, electrical brain stimulation, temporal separation of choice alternatives, behavior therapy, drug use, and addictions. Moreover, the generalized matching law (Baum, 1974) gains greater explanatory power and comprehensiveness when measures of substitutability are included. PMID:16812696

  14. Reinforced concrete tomography

    International Nuclear Information System (INIS)

    In this paper we describe the technique of reinforced concrete tomography, its historical background, recent technological developments and main applications. Gamma radiation sensitive plates are imprinted with radiation going through the concrete sample under study, and then processed to reveal the presence of reinforcement and defects in the material density. The three dimensional reconstruction, or tomography, of the reinforcement out of a single gammagraphy is an original development alternative to conventional methods. Re-bar diameters and positions may be determined with an accuracy of ± 1 mm 0.5-1 cm, respectively. The non-destructive character of this technique makes it particularly attractive in cases of inhabited buildings and diagnoses of balconies. (author)

  15. Turbomachine blade reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Crespo, Andres Jose

    2016-09-06

    Embodiments of the present disclosure include a system having a turbomachine blade segment including a blade and a mounting segment coupled to the blade, wherein the mounting segment has a plurality of reinforcement pins laterally extending at least partially through a neck of the mounting segment.

  16. Fibre reinforced polymer nanocomposites

    NARCIS (Netherlands)

    Vlasveld, D.P.N.

    2005-01-01

    In this thesis the results are described of the research on a combination of two types of composites: thermoplastic nanocomposites and continuous fibre composites. In this three-phase composite the main reinforcing phase are continuous glass or carbon fibres, and the matrix consists of a polyamide 6

  17. Reinforcement and learning

    NARCIS (Netherlands)

    Servedio, M.R.; Sæther, S.A.; Sætre, G.-P.

    2009-01-01

    Evidence has been accumulating to support the process of reinforcement as a potential mechanism in speciation. In many species, mate choice decisions are influenced by cultural factors, including learned mating preferences (sexual imprinting) or learned mate attraction signals (e.g., bird song). It

  18. Motivated Reinforcement Learning

    CERN Document Server

    Maher, Mary Lou

    2009-01-01

    Motivated learning is a research field in artificial intelligence and cognitive modelling. This book describes how motivated reinforcement learning agents can be used in computer games for the design of non-player characters that can adapt their behaviour in response to unexpected changes in their environment

  19. Short fiber reinforced thermoplastic blends

    NARCIS (Netherlands)

    Malchev, P.G.

    2008-01-01

    The present thesis investigates the potential of short fiber reinforced thermoplastic blends, a combination of an immiscible polymer blend and a short fiber reinforced composite, to integrate the easy processing solutions available for short fiber reinforced composites with the high mechanical perfo

  20. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik;

    2012-01-01

    reached causing the formation of anodic and cathodic regions along the reinforcement. Critical chloride thresholds, randomly distributed along the reinforcement sur-face, link the initiation and propagation phase of reinforcement corrosion. To demonstrate the potential use of the developed model, a......A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold is...

  1. Nanostructured composite reinforced material

    Science.gov (United States)

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  2. Fiber-reinforced fixed partial dentures: a preliminary retrospective clinical study Próteses parciais fixas reforçadas por fibras: um estudo clínico retrospectivo preliminar

    Directory of Open Access Journals (Sweden)

    Edno Moacir Piovesan

    2006-04-01

    Full Text Available The aim of this study was to evaluate the clinical performance (retention rate of fiber-reinforced composite fixed partial dentures (FPDs. Polyethylene fiber (Ribbond® was used combined with restorative composite during FPDs fabrication. FPDs were placed in thirteen patients in a private clinic. Nineteen FPDs were evaluated. The prosthetic space was filled with only one pontic using extracted teeth (2 cases, acrylic resin teeth (11 cases, or with composite resin (6 cases, combined with Polyethylene fiber. The clinical criterion used was based on retention rate of FPDs. If FPDs were in function in the mouth at the time of examination without previous repair they were classified as Complete Survival (CS restorations. A classification of Survival with Rebonding (SR was assigned in the event of an adhesive failure, but after rebonding the FPD still remained under evaluation. Treatment was classified as a Failure (F if the FPD restoration was lost. The time of evaluation was 41.15 months (±15.13. The FPDs evaluated were retained (CS=94.75%, and no failure was found except for in one situation which required rebonding (SR=5.25%. According to the survival estimation method of Kaplan-Meyer the mean survival time was 42.3 months. At the time of evaluation investigated, polyethylene-reinforced FPDs showed a favorable retention rate in preliminary data.O objetivo deste estudo foi avaliar a performance clínica (percentagem de retenção de próteses parciais fixas reforçadas por fibras. Fibras de polietileno (Ribbond® foram usadas em combinação com resina composta durante a confecção das próteses. Os tratamentos foram realizadas em 13 pacientes, em uma clínica privada., sendo que 19 próteses foram reavaliadas. O espaço protético era preenchido com um pôntico usando o próprio dente extraído (2 casos, dentes de acrílico (11 casos ou confeccionados com resina composta (6 casos, em todas as situações eram empregadas fibras de polietileno. Os

  3. Reinforcement of ceramic materials

    International Nuclear Information System (INIS)

    In the commercial field, greater reproduceability of ceramic materials was achieved by systematic process control of the steps in manufacture. By improvement of the microstructure design, the strength and toughness against tearing of the materials were increased. The articles give a survey of theoretical and experimental results in manufacture and of the composition of ceramics with reinforced structure. Preferred materials are zirconium-, aluminium- and yttrium oxide, silicon oxide and -nitride and titanium- and silicon carbide. (DG)

  4. Fibre-reinforced thermoplastics

    OpenAIRE

    Røsand, Vegar Rydén

    2011-01-01

    This thesis presents experimental tests of fibre-reinforced polypropylene, as well as calibration of material coefficients and simulations of experimental tests. The focus is on exploring the dependence on loading direction to fibre direction and rate of strain, and on validation of the material coefficient.First the material and the experimental procedure is presented together with the results from the tests.Uniaxial tension tests, cyclic loading-unloading tests and components tests is perfo...

  5. Fibre reinforced polymer nanocomposites

    OpenAIRE

    Vlasveld, D.P.N.

    2005-01-01

    In this thesis the results are described of the research on a combination of two types of composites: thermoplastic nanocomposites and continuous fibre composites. In this three-phase composite the main reinforcing phase are continuous glass or carbon fibres, and the matrix consists of a polyamide 6 / layered silicate nanocomposite. To be able to produce and understand this new type of thermoplastic composite, the properties of the nanocomposite matrix materials have been investigated, follow...

  6. Fiber reinforced polypropylene nanocomposites

    OpenAIRE

    Houphouet-Boigny, Chrystèle

    2007-01-01

    The aim of this thesis is to assess the feasibility of integrating nanoparticles into glass fiber (GF) reinforced isotactic polypropylene (iPP) composites via existing thermoplastic processing routes, and to investigate whether this results in significant improvements in the mechanical properties of the final composites. A longer term aim will be to extend the approach to the preparation of hybrid composites with added non-structural functionality. However, the nanoparticles that have provide...

  7. Fiber reinforced polypropylene nanocomposites

    OpenAIRE

    Houphouet-Boigny, Chrystèle; Månson, Jan-Anders E.; Plummer, John Christopher

    2008-01-01

    The aim of this thesis is to assess the feasibility of integrating nanoparticles into glass fiber (GF) reinforced isotactic polypropylene (iPP) composites via existing thermoplastic processing routes, and to investigate whether this results in significant improvements in the mechanical properties of the final composites. A longer term aim will be to extend the approach to the preparation of hybrid composites with added non-structural functionality. However, the nanoparticles that have provide...

  8. Reinforced aerodynamic profile

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention relates to the prevention of deformations in an aerodynamic profile caused by lack of resistance to the bending moment forces that are created when such a profile is loaded in operation. More specifically, the invention relates to a reinforcing element inside an aerodynamic ...... profile and a method for the construction thereof. The profile is intended for, but not limited to, useas a wind turbine blade, an aerofoil device or as a wing profile used in the aeronautical industry....

  9. Corrosion of reinforcement bars in steel ibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe

    perpendicular to the reinforcement bar) was reduced for SFRC compared to plain concrete, whereas there was no clear impact on the slip at the concrete/steel-bar (displacement discontinuity parallel to the reinforcement bar) caused by the steel fibres. Additional experimental and numerical studies concerning......Steel fibres have been known as an alternative to traditional reinforcement bars for special applications of structural concrete for decades and the use of steel fibre reinforced concrete (SFRC) has gradually increased in recent years. Steel fibres lead to reduced crack widths in concrete formed......, among other reasons, due to shrinkage and/or mechanical loading. Steel fibres are nowadays also used in combination with traditional reinforcement for structural concrete, where the role of the fibres is to minimize the crack widths whereas the traditional reinforcement bars are used for structural...

  10. Slender reinforced concrete columns strengthened with fibre reinforced polymers

    Science.gov (United States)

    Gajdošová, K.; Bilčík, J.

    2011-06-01

    The requirement for a long life with relatively low maintenance costs relates to the use of building structures. Even though the structure is correctly designed, constructed and maintained, the need for extensions of its lifetime can appear. The preservation of the original structure with a higher level of resistance or reliability is enabled by strengthening. Conventional materials are replaced by progressive composites - mainly carbon fibre reinforced polymers (CFRP). They are used for strengthening reinforced concrete columns in two ways: added reinforcement in the form of CFRP strips in grooves or CFRP sheet confinement and eventually their combination. This paper presents the effect of the mentioned strengthening methods on slender reinforced concrete columns.

  11. Reinforcement in opinion dynamics

    Science.gov (United States)

    Volovik, Daniel

    I consider the evolution and acceptance of a new opinion in a population of unaware agents by using physics-based models of contagion spread. These models rely upon agent-based dynamics, in which an agent changes opinion by interactions with neighbors according to specific interactions. Most of these models have the feature that only a single input is required to change the opinion of an agent --- an agent has no commitment to its current opinion and accepts a new idea at the slightest provocation. These single-input models fail to account for people's confidence in their own beliefs. Thus I study the concept of social reinforcement --- that an agent adopts a new opinion only after multiple reinforcing prompts. Building on single-input models, I introduce two models of opinion spreading that incorporate a social reinforcement mechanism. (a) In the irreversible innovation and in the transient fad spreading models, a development is initially known only to a small portion of the population and subsequently spreads. An individual requires M > 1 interactions with an adopter before adopting the development. The ultimate extent of a transient fad depends critically on the characteristic time the fad keeps the attention of an adopting agent. (b) In the confident voter model, a voter can be in one of two opinion states and can additionally have two levels of commitment to an opinion: confident and vacillating. Upon interacting with an agent of a different opinion, a confident voter becomes less committed, or vacillating, but does not change opinion. However, a vacillating agent changes opinion by interacting with an agent of a different opinion. In two dimensions, the distribution of consensus times is characterized by two distinct times one that scales linearly with N and another that appears to scale as N 3/2. The longer time arises from configurations that fall into long-lived states that consist of multiple single-opinion stripes before consensus is reached.

  12. Conditioned Reinforcement and Response Strength

    OpenAIRE

    Shahan, Timothy A

    2010-01-01

    Stimuli associated with primary reinforcers appear themselves to acquire the capacity to strengthen behavior. This paper reviews research on the strengthening effects of conditioned reinforcers within the context of contemporary quantitative choice theories and behavioral momentum theory. Based partially on the finding that variations in parameters of conditioned reinforcement appear not to affect response strength as measured by resistance to change, long-standing assertions that conditioned...

  13. Negative effects of positive reinforcement

    OpenAIRE

    Perone, Michael

    2003-01-01

    Procedures classified as positive reinforcement are generally regarded as more desirable than those classified as aversive—those that involve negative reinforcement or punishment. This is a crude test of the desirability of a procedure to change or maintain behavior. The problems can be identified on the basis of theory, experimental analysis, and consideration of practical cases. Theoretically, the distinction between positive and negative reinforcement has proven difficult (some would say t...

  14. The Reinforcement Learning Competition 2014

    OpenAIRE

    Dimitrakakis, Christos; Chalmers University of Technology; Li, Guangliang; University of Amsterdam; Tziortziotis, Nikoalos; University of Ioannina

    2014-01-01

    Reinforcement learning is one of the most general problems in artificial intelligence. It has been used to model problems in automated experiment design, control, economics, game playing, scheduling and telecommunications. The aim of the reinforcement learning competition is to encourage the development of very general learning agents for arbitrary reinforcement learning problems and to provide a test-bed for the unbiased evaluation of algorithms.

  15. Recycling of Reinforced Plastics

    Science.gov (United States)

    Adams, R. D.; Collins, Andrew; Cooper, Duncan; Wingfield-Digby, Mark; Watts-Farmer, Archibald; Laurence, Anna; Patel, Kayur; Stevens, Mark; Watkins, Rhodri

    2014-02-01

    This work has shown is that it is possible to recycle continuous and short fibre reinforced thermosetting resins while keeping almost the whole of the original material, both fibres and matrix, within the recyclate. By splitting, crushing hot or cold, and hot forming, it is possible to create a recyclable material, which we designate a Remat, which can then be used to remanufacture other shapes, examples of plates and tubes being demonstrated. Not only can remanufacturing be done, but it has been shown that over 50 % of the original mechanical properties, such as the E modulus, tensile strength, and interlaminar shear strength, can be retained. Four different forms of composite were investigated, a random mat Glass Fibre Reinforced Plastic (GFRP) bathroom component and boat hull, woven glass and carbon fibre cloth impregnated with an epoxy resin, and unidirectional carbon fibre pre-preg. One of the main factors found to affect composite recyclability was the type of resin matrix used in the composite. Thermoset resins tested were shown to have a temperature range around the Glass Transition Temperature (Tg) where they exhibit ductile behaviour, hence aiding reforming of the material. The high-grade carbon fibre prepreg was found to be less easy to recycle than the woven of random fibre laminates. One method of remanufacturing was by heating the Remat to above its glass transition temperature, bending it to shape, and then cooling it. However, unless precautions are taken, the geometric form may revert. This does not happen with the crushed material.

  16. Corrosion Inhibitors for Reinforced Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Steel corrosion in reinforced concrete structures has been a major problem across the U.S. Steel-reinforced concrete structures are continually subject to attack by corrosion brought on by naturally occurring environmental conditions. FerroGard, a corrosion inhibitor, developed by Sika Corporation, penetrates hardened concrete to dramatically reduce corrosion by 65% and extend the structure's service life.

  17. Conditioned Reinforcement and Response Strength

    Science.gov (United States)

    Shahan, Timothy A.

    2010-01-01

    Stimuli associated with primary reinforcers appear themselves to acquire the capacity to strengthen behavior. This paper reviews research on the strengthening effects of conditioned reinforcers within the context of contemporary quantitative choice theories and behavioral momentum theory. Based partially on the finding that variations in…

  18. Delayed Reinforcement of Operant Behavior

    Science.gov (United States)

    Lattal, Kennon A.

    2010-01-01

    The experimental analysis of delay of reinforcement is considered from the perspective of three questions that seem basic not only to understanding delay of reinforcement but also, by implication, the contributions of temporal relations between events to operant behavior. The first question is whether effects of the temporal relation between…

  19. Stochastic Reinforcement Benefits Skill Acquisition

    Science.gov (United States)

    Dayan, Eran; Averbeck, Bruno B.; Richmond, Barry J.; Cohen, Leonardo G.

    2014-01-01

    Learning complex skills is driven by reinforcement, which facilitates both online within-session gains and retention of the acquired skills. Yet, in ecologically relevant situations, skills are often acquired when mapping between actions and rewarding outcomes is unknown to the learning agent, resulting in reinforcement schedules of a stochastic…

  20. Carbon Nanotubes Reinforced Composites for Biomedical Applications

    OpenAIRE

    Wei Wang(College of William and Mary); Yuhe Zhu; Susan Liao; Jiajia Li

    2014-01-01

    This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matr...

  1. Non-metallic shear reinforcement for reinforced concrete beams

    Energy Technology Data Exchange (ETDEWEB)

    Erki, M.A. [Royal Military Coll. of Canada, Kingston, ON (Canada). Dept. of Civil Engineering; Bakht, B. [Ontario Ministry of Transportation, Downsview, ON (Canada). Engineering Materials Office

    1996-09-01

    An alternative to using steel as a reinforcement in concrete was described. The material was a non-corroding fibre reinforced plastic (FRP), consisting of high strength fibres in an epoxy matrix. The corrosion of the steel in reinforced concrete is a major problem facing cold regions that use de-icing salts on roadways. Shear reinforcement made of FRP bars have the traditional designs for steel shear reinforcements that introduce bends in the material, such as for rectangular stirrups. The strength of a bent FRP bar is significantly reduced compared to the strength of a straight FRP bar, because of uneven sharing of stresses by the fibres at the bends. A viable alternative FRP shear reinforcement was proposed that does not require the use of a bend in the FRP bar, but instead, uses a series of FRP bars bent into planar grid sheets. It was concluded that constructing the beams with the FRP grids was more cost effective since less labour for preparation and installation of the reinforcement was required. 6 refs., 5 figs.

  2. Shear Behavior of Concrete Beams Reinforced with GFRP Shear Reinforcement

    OpenAIRE

    Heecheul Kim; Min Sook Kim; Myung Joon Ko; Young Hak Lee

    2015-01-01

    This paper presents the shear capacities of concrete beams reinforced with glass fiber reinforced polymer (GFRP) plates as shear reinforcement. To examine the shear performance, we manufactured and tested a total of eight specimens. Test variables included the GFRP strip-width-to-spacing ratio and type of opening array. The specimen with a GFRP plate with a 3×2 opening array showed the highest shear strength. From the test results, the shear strength increased as the strip-width-to-strip-spac...

  3. Shear Behavior of Concrete Beams Reinforced with GFRP Shear Reinforcement

    Directory of Open Access Journals (Sweden)

    Heecheul Kim

    2015-01-01

    Full Text Available This paper presents the shear capacities of concrete beams reinforced with glass fiber reinforced polymer (GFRP plates as shear reinforcement. To examine the shear performance, we manufactured and tested a total of eight specimens. Test variables included the GFRP strip-width-to-spacing ratio and type of opening array. The specimen with a GFRP plate with a 3×2 opening array showed the highest shear strength. From the test results, the shear strength increased as the strip-width-to-strip-spacing ratio increased. Also, we used the experimental results to evaluate whether the shear strength equations of ACI 318-14 and ACI 440.1R can be applied to the design of GFRP shear reinforcement. In the results, the ACI 440 equation underestimated the experimental results more than that of ACI 318.

  4. Flexural reinforcement of concrete with textile reinforced mortar TRM

    OpenAIRE

    Gil Espert, Lluís; Escrig Pérez, Christian; Bernat Masó, Ernest

    2013-01-01

    This work presents a method of strengthening concrete structures based on textiles of high strength and mortars. The combination of textiles and mortars produces a new composite material of cementitic matrix. This material can be used for the reinforcement of concrete beams under bending loads. We tested several combinations of fibers: glass, PBO, steel and carbon fibers with mortar and we used them to reinforce precast concrete beams. All the specimens were tested with a four-point load test...

  5. Evolutionary computation for reinforcement learning

    NARCIS (Netherlands)

    S. Whiteson

    2012-01-01

    Algorithms for evolutionary computation, which simulate the process of natural selection to solve optimization problems, are an effective tool for discovering high-performing reinforcement-learning policies. Because they can automatically find good representations, handle continuous action spaces, a

  6. Reinforcement of concrete structures by fiberglass rods

    OpenAIRE

    Avdeeva Arina; Shlykova Inga; Antonova Maria; Barabanschikov Yuri; Belyaeva Svetlana

    2016-01-01

    In this article we introduced conducted experiments to determine the basic characteristics of composite reinforcement fiberglass reinforcement on the example of the same diameter, but with a different number of rovings. We have established strength along the reinforcing fiber and the corresponding class of the steel reinforcement.

  7. Reinforcement Learning via AIXI Approximation

    OpenAIRE

    Veness, Joel; Ng, Kee Siong; Hutter, Marcus; Silver, David

    2010-01-01

    This paper introduces a principled approach for the design of a scalable general reinforcement learning agent. This approach is based on a direct approximation of AIXI, a Bayesian optimality notion for general reinforcement learning agents. Previously, it has been unclear whether the theory of AIXI could motivate the design of practical algorithms. We answer this hitherto open question in the affirmative, by providing the first computationally feasible approximation to the AIXI agent. To deve...

  8. Fiber-reinforced tough hydrogels

    OpenAIRE

    Illeperuma, Widusha Ruwangi Kaushalya; Sun, Jeong-Yun; Suo, Zhigang; Vlassak, Joost J.

    2014-01-01

    Using strong fibers to reinforce a hydrogel is highly desirable but difficult. Such a composite would combine the attributes of a solid that provides strength and a liquid that transports matter. Most hydrogels, however, are brittle, allowing the fibers to cut through the hydrogel when the composite is loaded. Here we circumvent this problem by using a recently developed tough hydrogel. We fabricate a composite using an alginate-polyacrylamide hydrogel reinforced with a random network of stai...

  9. Evolutionary Algorithms for Reinforcement Learning

    OpenAIRE

    Grefenstette, J. J.; Moriarty, D. E.; Schultz, A.C.

    2011-01-01

    There are two distinct approaches to solving reinforcement learning problems, namely, searching in value function space and searching in policy space. Temporal difference methods and evolutionary algorithms are well-known examples of these approaches. Kaelbling, Littman and Moore recently provided an informative survey of temporal difference methods. This article focuses on the application of evolutionary algorithms to the reinforcement learning problem, emphasizing alternative policy represe...

  10. Reinforcement contingencies and social reinforcement: some reciprocal relations between basic and applied research.

    OpenAIRE

    Vollmer, T R; Hackenberg, T D

    2001-01-01

    Reinforcement contingencies and social reinforcement are ubiquitous phenomena in applied behavior analysis. This discussion paper is divided into two sections. In the first section, reinforcement contingencies are discussed in terms of the necessary and sufficient conditions for reinforcement effects. Response-stimulus dependencies, conditional probabilities, and contiguity are discussed as possible mechanisms of, and arrangements for, reinforcement effects. In the second section, social rein...

  11. Applied Implications of Reinforcement History Effects

    OpenAIRE

    Pipkin, Claire St. Peter; Vollmer, Timothy R

    2009-01-01

    Although the influence of reinforcement history is a theoretical focus of behavior analysis, the specific behavioral effects of reinforcement history have received relatively little attention in applied research and practice. We examined the potential effects of reinforcement history by reviewing nonhuman, human operant, and applied research and interpreted the findings in relation to possible applied significance. The focus is on reinforcement history effects in the context of reinforcement ...

  12. Structure and properties of textile reinforced concrete

    OpenAIRE

    Volkova, A.A.; A.V. Paykov; O.N. Stolyarov; S.G. Semenov; B.E. Melnikov

    2015-01-01

    In this paper the structure and properties of textile-reinforced concrete were investigated. Two types of high strength reinforcing fabrics made of glass and carbon rovings were used in this study. The samples of textile-reinforced concrete were produced. The mechanical properties of the developed samples were determined via a three-point bending test. The maximum flexural strength and reinforcement efficiency were calculated. It was found that the samples with textile reinforcement have high...

  13. Theoretical Analysis of Reinforcement Tunnel Lining Corrosion

    OpenAIRE

    ZhiQiang Zhangand; Yousif A. Mansoor; Fan Hong Wei

    2013-01-01

    The main cause of ageing damage in reinforced concrete structures is reinforcement corrosion. Damage can be detected visually as coincident cracks along the reinforcement bar, which are significant of both reduction of the re-bar, cross-section and loss of bond strength for reinforced concrete. The reinforced concrete is one of the most widely used engineering materials as final lining of tunnels. The corrosion is common durability problems that have significant effect on the tunnel performan...

  14. Improved bondability of wax-treated wood following plasma treatment

    OpenAIRE

    Avramidis, Georg; Scholz, Gunthard; Nothnick, Evelyn; Militz, Holger; Viöl, Wolfgang; Wolkenhauer, Arndt

    2011-01-01

    In this study, the impact of a plasma treatment using dielectric barrier discharge at atmospheric pressure on wax-treated beech was investigated by surface energy determination and adhesion tests. Measurements of the surface energy revealed a strong increase in surface polarity along with increased surface energy as a result of the plasma treatment, pointing to increased adhesion properties. To evaluate the adhesion properties of a polyvinyl acetate (PVAc) adhesive on beech treated with monta...

  15. Silica reinforced triblock copolymer gels

    DEFF Research Database (Denmark)

    Theunissen, E.; Overbergh, N.; Reynaers, H.;

    2004-01-01

    scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from a...... viscoclastic rubber to a plastic fluid and from a plastic fluid to a viscoelastic liquid are shifted to more elevated temperatures when silica is added to the triblock copolymer gel. (C) 2004 Elsevier Ltd. All rights reserved.......The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order to...

  16. Quenched Reinforcement Exposed to Fire

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    2006-01-01

    Idealized data are derived for the tensile strength of quenched and tempered prestressing steel and of quenched and self-tempered reinforcing bars for fire safety design. 0.2% stresses are derived as a function of the maximum temperature and in addition, 2.0% stresses are provided. A strain of 2.......0% is seldom found in “slack” (not prestressed) reinforcement, but 2.0% stresses might be relevant for reinforcement in T shaped cross sections and for prestressed structures, where large strains can be applied. All data are provided in a “HOT” condition during a fire and in a “COLD” condition after a...... fire. The COLD condition is relevant for analyses of residual load bearing capacity of a structure after a fire exposure. It is also relevant for analyses of concrete structures exposed to fully developed fire courses. The reason is that compression zones of concrete are always the weakest in the...

  17. Analytical Study Of Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Hosam A. Dahaam

    2013-05-01

    Full Text Available Nonlinear finite element analyses is carried out using the ANSYS11 program to predict the ultimate load for two different types of reinforced concrete continuous two-span deep beams. Results of comparing analytical with  experimental data demonstrates the accuracy of the program. The effects of longitudinal reinforcement and web openings are studied and showed that the longitudinal reinforcement at top and middle region has little effect on the ultimate load, and the effect of web opening location has  great effect on the ultimate load especially when the load path passes through the openings centerline. Web opening location also has  great effect on values and distribution of shear and normal stresses especially at opening region.   

  18. Quenched Reinforcement Exposed to Fire

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    2006-01-01

    investigated. Therefore, two test series have been made, which are presented in the present paper. In one test series, transient properties are found in a HOT condition during a fire and in the other, residual properties are found in a COLD condition after a fully developed fire course.......Idealized data are derived for the tensile strength of quenched and tempered prestressing steel and of quenched and self-tempered reinforcing bars for fire safety design. 0.2% stresses are derived as a function of the maximum temperature and in addition, 2.0% stresses are provided. A strain of 2.......0% is seldom found in “slack” (not prestressed) reinforcement, but 2.0% stresses might be relevant for reinforcement in T shaped cross sections and for prestressed structures, where large strains can be applied. All data are provided in a “HOT” condition during a fire and in a “COLD” condition after a...

  19. The power reinforcement framework revisited

    DEFF Research Database (Denmark)

    Nielsen, Jeppe; Andersen, Kim Normann; Danziger, James N.

    2016-01-01

    -making and gained most benefits from mobile technology use, relative to the effects of the technology on the street-level workers who deliver services. Current mobile technology-in-use might be less likely to be power reinforcing because it is far more decentralized and individualized than the mainly expert......Whereas digital technologies are often depicted as being capable of disrupting long-standing power structures and facilitating new governance mechanisms, the power reinforcement framework suggests that information and communications technologies tend to strengthen existing power arrangements within...

  20. Reinforcer Accumulation in a Token-Reinforcement Context with Pigeons

    Science.gov (United States)

    Yankelevitz, Rachelle L.; Bullock, Christopher E.; Hackenberg, Timothy D.

    2008-01-01

    Four pigeons were exposed to a token-reinforcement procedure with stimulus lights serving as tokens. Responses on one key (the token-production key) produced tokens that could be exchanged for food during an exchange period. Exchange periods could be produced by satisfying a ratio requirement on a second key (the exchange-production key). The…

  1. What Happens with Reinforced Concrete Structures when the Reinforcement Corrodes

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper, corrosion of reinforced concrete structures is discussed from the point of view of corrosion products. The different types of corrosion products are presented and a detailed study of the important diffusion coefficient is performed. Stochastic modelling of corrosion initiated...

  2. Topology optimization of reinforced concrete structures

    DEFF Research Database (Denmark)

    Amir, Oded

    Recent advances regarding topology optimization procedures of reinforced concrete structures are presented. We discuss several approaches to the challenging problem of optimizing the distribution of concrete and steel reinforcement. In particular, the consideration of complex nonlinear constituti...

  3. Ensemble algorithms in reinforcement learning

    NARCIS (Netherlands)

    Wiering, Marco A; van Hasselt, Hado

    2008-01-01

    This paper describes several ensemble methods that combine multiple different reinforcement learning (RL) algorithms in a single agent. The aim is to enhance learning speed and final performance by combining the chosen actions or action probabilities of different RL algorithms. We designed and imple

  4. Brucite nanoplate reinforced starch bionanocomposites

    Science.gov (United States)

    In this paper the mechanical reinforcement in a series of bionanocomposites films based on starch and nano-sized brucite, Mg(OH)2, was investigated. Brucite nanoplates with an aspect ratio of 9.25 were synthesized by wet precipitation and incorporated into starch matrices at different concentrations...

  5. Classifying Options for Deep Reinforcement Learning

    OpenAIRE

    Arulkumaran, Kai; Dilokthanakul, Nat; Shanahan, Murray; Bharath, Anil Anthony

    2016-01-01

    Deep reinforcement learning is the learning of multiple levels of hierarchical representations for reinforcement learning. Hierarchical reinforcement learning focuses on temporal abstractions in planning and learning, allowing temporally-extended actions to be transferred between tasks. In this paper we combine one method for hierarchical reinforcement learning - the options framework - with deep Q-networks (DQNs) through the use of different "option heads" on the policy network, and a superv...

  6. Flexural Behavior of Textile-Reinforced Concrete

    OpenAIRE

    Volkova Anna; Paykov Alexey; Semenov Sergey; Stolyarov Oleg; Melnikov Boris

    2016-01-01

    This paper deals with the flexural behaviour of textile-reinforced concrete (TRC). Two samples of TRC made of high strength reinforcing fabrics made of glass and carbon rovings were produced. Three-point bending test was carried out to examine the flexural performance of the developed samples. The maximum flexural strength and reinforcement efficiency were calculated. Experimental results showed that that all types of applied fabric reinforcement contributed to increases strength as compared ...

  7. Hybrid composite rods for concrete reinforcement

    OpenAIRE

    Fangueiro, Raúl; Pereira, Cristiana Gonilho; Jalali, Said; Araújo, Mário Duarte de; Marques, P.

    2010-01-01

    The current work is concerned with the development of braided composite rods for civil engineering applications, namely for concrete internal reinforcement, as a steel substitute. The research study aims at understanding the tensile behaviour of composite rods reinforced by a textile structure – braided structure with core reinforcement.Seven types of braided composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided structure. ...

  8. Choice and the relative immediacy of reinforcement

    OpenAIRE

    Dunn, Roger; Fantino, Edmund

    1982-01-01

    The relative immediacy of reinforcement in concurrent-chain schedules was varied while the relative reduction in the overall average time to reinforcement associated with terminal-link entry was held constant. For each of four pigeons, choice did not vary with relative immediacy of reinforcement. Subsequently, choice by the same subjects was shown to be sensitive to relative reduction in average time to reinforcement.

  9. 49 CFR 178.345-7 - Circumferential reinforcements.

    Science.gov (United States)

    2010-10-01

    ... circumferential reinforcement member, whether internal or external, reinforcement must be continuous around the... tank heads. (1) Circumferential reinforcement must be located so that the thickness and tensile strength of the shell material in combination with the frame and reinforcement produces...

  10. Conditioned Reinforcement Value and Resistance to Change

    Science.gov (United States)

    Shahan, Timothy A.; Podlesnik, Christopher A.

    2008-01-01

    Three experiments examined the effects of conditioned reinforcement value and primary reinforcement rate on resistance to change using a multiple schedule of observing-response procedures with pigeons. In the absence of observing responses in both components, unsignaled periods of variable-interval (VI) schedule food reinforcement alternated with…

  11. Examination and reinforcement technologies for masonry structures

    Directory of Open Access Journals (Sweden)

    V.N. Derkach

    2010-11-01

    Full Text Available In the article the analysis of major methods for monitoring of masonry buildings for the purpose of cracking. Also different ways of reinforcement are given. The authors focus attention on comparison of national and foreign practice in this area. Modern methods of reinforcement are depicted such as Fibre Reinforced Cementitious Matrix (FRCM and Brutt Technologies.

  12. Comparative study of reinforced nozzle connections

    International Nuclear Information System (INIS)

    The shell theory and finite-element method are used for the stress analysis of models of unreinforced and reinforced nozzle connections under internal pressure and external loads. Various reinforcement configurations are considered. The results of a comparative study of the effects of reinforcement on the maximum stress in radial models of the intersecting cylindrical shells are presented. (orig.)

  13. Applied Implications of Reinforcement History Effects

    Science.gov (United States)

    Pipkin, Claire St. Peter; Vollmer, Timothy R.

    2009-01-01

    Although the influence of reinforcement history is a theoretical focus of behavior analysis, the specific behavioral effects of reinforcement history have received relatively little attention in applied research and practice. We examined the potential effects of reinforcement history by reviewing nonhuman, human operant, and applied research and…

  14. Quantification of rats' behavior during reinforcement periods

    OpenAIRE

    Gunn, Kenneth P.

    1983-01-01

    What is treated as a single unit of reinforcement often involves what could be called a reinforcement period during which two or more acts of ingestion may occur, and each of these may have associated with it a series of responses, some reflexive, some learned, that lead up to ingestion. Food-tray presentation to a pigeon is an example of such a “reinforcement period.” In order to quantify this behavior, a continuous-reinforcement schedule was used as the reinforcement period and was chained ...

  15. Flexural Behavior of Textile-Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Volkova Anna

    2016-01-01

    Full Text Available This paper deals with the flexural behaviour of textile-reinforced concrete (TRC. Two samples of TRC made of high strength reinforcing fabrics made of glass and carbon rovings were produced. Three-point bending test was carried out to examine the flexural performance of the developed samples. The maximum flexural strength and reinforcement efficiency were calculated. Experimental results showed that that all types of applied fabric reinforcement contributed to increases strength as compared to nonreinforced concrete. Furthermore, the deformation behavior of reinforced concrete was analyzed. The advantage is in higher residual load-bearing capacity, which allows maintaining the integrity of the structure.

  16. Woodflour as Reinforcement of Polypropylene

    Directory of Open Access Journals (Sweden)

    José Cláudio Caraschi

    2002-10-01

    Full Text Available The effect of the filler content and size, as well as accelerated aging on the mechanical properties of polypropylene composites reinforced with woodflour (WF/PP were evaluated. The composites were prepared by the extrusion of polypropylene with woodflour (Pinus elliotti based on following ratios: 15, 25 and 40 wt% with two different granulometries. The specimens were injection molded according to ASTM standards. The composite properties did not show significant differences as a function of the filler granulometry. We also observed that by increasing the filler content, both the mechanical properties and the melt flow index (MFI decreased, and the elasticity modulus, hardness and density increased. Concerning the accelerated aging, the composite presented a reduction in tensile properties. The results showed that the composite properties are extremely favorable when compared to other commercial systems reinforced by inorganic fillers.

  17. Alumina-Reinforced Zirconia Composites

    Science.gov (United States)

    Choi, Sung R.; Bansal, Narottam P.

    2003-01-01

    Alumina-reinforced zirconia composites, used as electrolyte materials for solid oxide fuel cells, were fabricated by hot pressing 10 mol percent yttria-stabilized zirconia (10-YSZ) reinforced with two different forms of alumina particulates and platelets each containing 0 to 30 mol percent alumina. Major mechanical and physical properties of both particulate and platelet composites including flexure strength, fracture toughness, slow crack growth, elastic modulus, density, Vickers microhardness, thermal conductivity, and microstructures were determined as a function of alumina content either at 25 C or at both 25 and 1000 C. Flexure strength and fracture toughness at 1000 C were maximized with 30 particulate and 30 mol percent platelet composites, respectively, while resistance to slow crack growth at 1000 C in air was greater for 30 mol percent platelet composite than for 30 mol percent particulate composites.

  18. Grammatical Evolution Guided by Reinforcement

    OpenAIRE

    Mingo, Jack Mario; Aler, Ricardo

    2007-01-01

    Grammatical evolution is an evolutionary algorithm able to develop, starting from a grammar, programs in any language. Starting from the point that individual learning can improve evolution, in this paper it is proposed an extension of Grammatical evolution that looks at learning by reinforcement as a learning method for individuals. This way, it is possible to incorporate the Baldwinian mechanism to the evolutionary process. The effect is widened with the introduction of the Lamarck hypothes...

  19. Adaptive Bases for Reinforcement Learning

    CERN Document Server

    Di Castro, Dotan

    2010-01-01

    We consider the problem of reinforcement learning using function approximation, where the approximating basis can change dynamically while interacting with the environment. A motivation for such an approach is maximizing the value function fitness to the problem faced. Three errors are considered: approximation square error, Bellman residual, and projected Bellman residual. Algorithms under the actor-critic framework are presented, and shown to converge. The advantage of such an adaptive basis is demonstrated in simulations.

  20. Cover Tree Bayesian Reinforcement Learning

    OpenAIRE

    Tziortziotis, Nikolaos; Dimitrakakis, Christos; Blekas, Konstantinos

    2013-01-01

    This paper proposes an online tree-based Bayesian approach for reinforcement learning. For inference, we employ a generalised context tree model. This defines a distribution on multivariate Gaussian piecewise-linear models, which can be updated in closed form. The tree structure itself is constructed using the cover tree method, which remains efficient in high dimensional spaces. We combine the model with Thompson sampling and approximate dynamic programming to obtain effective exploration po...

  1. COAL REINFORCED COMPOSITE POLYAMIDE NANOFIBERS

    OpenAIRE

    R. Keskin; I. Gocek; U. K. Sahin; O. B. Berkalp; N. Acarkan; Ozkan, S.; C. D. Dikmen; E. Daskaya; H. Saglam

    2013-01-01

    Polymer nanocomposites are novel classes of composite materials derived from nanoparticles with at least one dimension in the nanometric range. Nanofibers that are produced by electrospinning process have a wide range of use in different textile applications including medical textiles, filtration textiles, protective clothing, as well as coatings for various purposes [1-4]. The aim of this study is to design and develop nanosized coal reinforced composite polyamide (PA) nanofibers by electros...

  2. Polymer nanocomposites reinforced with montmorillonite

    OpenAIRE

    L.A. Dobrzański; M. Bilewicz; Viana, J. C.

    2012-01-01

    Purpose: Light microscope with polarized light has been used for observation layered zone, visible thanks to polarization of the light, inside polymer-polymer composites and nanocomposites Aim of work has been concentrated on investigation of nanocomposites as promising engineering materials, basing on composition of polypropylene and montmorillonite as reinforcement in the shape of nanoparticles of 2:1 silicate.Design/methodology/approach: Conventional and non-conventional injection molding ...

  3. Reinforcement Learning or Active Inference?

    OpenAIRE

    Friston, K.; Daunizeau, J.; Kiebel, S.

    2009-01-01

    This paper questions the need for reinforcement learning or control theory when optimising behaviour. We show that it is fairly simple to teach an agent complicated and adaptive behaviours using a free-energy formulation of perception. In this formulation, agents adjust their internal states and sampling of the environment to minimize their free-energy. Such agents learn causal structure in the environment and sample it in an adaptive and self-supervised fashion. This results in behavioural p...

  4. Fiber reinforced titanium alloy composites

    International Nuclear Information System (INIS)

    The more important titanium matrix composites studied to date are composed of titanium alloy matrices, such as Ti 6Al--4V, reinforced with filaments of boron, silicon carbide, or sapphire, as well as with wires of beryllium or refractory metal alloys. The primary fabrication techniques for these materials involve vacuum hot pressing at 1300 to 16000F, alternate layers of titanium alloy matrix foils, and suitably aligned filament mats. The more ductile reinforcements such as beryllium, have been incorporated into titanium matrix composites by coextrusion. Fabrication of composite gas turbine engine fan blades from both boron (SiC coated) and beryllium reinforced Ti 6Al--4V alloy is described. Feasibility studies have been made in the fabrication of Boron/Ti 6Al--4V composite rings for possible gas turbine engine disc applications. Mechanical properties of various titanium matrix composite systems are presented and demonstrate the attractive elevated temperature properties of some systems to 10000F. (35 fig, 6 tables) (U.S.)

  5. Responding during reinforcement delay in a self-control paradigm.

    OpenAIRE

    Logue, A. W.; Peña-Correal, T E

    1984-01-01

    Eight pigeons chose between a small, immediate reinforcer and a large, increasingly delayed reinforcer. Responding during the large-reinforcer delays was examined. During large-reinforcer delays, pecks on one key produced the small, immediate reinforcer; pecks on the other key had no effect. Thus, a pigeon could reverse its initial choice of the large, delayed reinforcer, or it could maintain its original choice. Pigeons that made a relatively high number of initial large-reinforcer choices t...

  6. Structure and properties of textile reinforced concrete

    Directory of Open Access Journals (Sweden)

    A.A. Volkova

    2015-11-01

    Full Text Available In this paper the structure and properties of textile-reinforced concrete were investigated. Two types of high strength reinforcing fabrics made of glass and carbon rovings were used in this study. The samples of textile-reinforced concrete were produced. The mechanical properties of the developed samples were determined via a three-point bending test. The maximum flexural strength and reinforcement efficiency were calculated. It was found that the samples with textile reinforcement have higher strength characteristics as compared to nonreinforced concrete. Furthermore, the deformation behavior of reinforced concrete was analyzed. The advantage is in higher residual load-bearing capacity, which allows maintaining the integrity of the structure.

  7. Reinforcement learning and its application to Othello

    OpenAIRE

    Wezel, Michiel; van Eck, Nees Jan

    2005-01-01

    textabstractIn this article we describe reinforcement learning, a machine learning technique for solving sequential decision problems. We describe how reinforcement learning can be combined with function approximation to get approximate solutions for problems with very large state spaces. One such problem is the board game Othello, with a state space size of approximately 1028. We apply reinforcement learning to this problem via a computer program that learns a strategy (or policy) for Othell...

  8. Reinforcement learning and its application to Othello

    OpenAIRE

    2005-01-01

    In this article we describe reinforcement learning, a machine learning technique for solving sequential decision problems. We describe how reinforcement learning can be combined with function approximation to get approximate solutions for problems with very large state spaces. One such problem is the board game Othello, with a state space size of approximately 1028. We apply reinforcement learning to this problem via a computer program that learns a strategy (or policy) for Othello by playing...

  9. Concrete and reinforced concrete - glance at future

    OpenAIRE

    Tamrazyan Ashot Georgievich

    2014-01-01

    In the article the information on the upcoming international conference on concrete and reinforced concrete is offered. The aim of the conference is stated, as well as the main points of the program, composition of the conference, the papers’ subject is disclosed. The author highlights the effect of reinforced concrete invention on the world civilization development. According to the author’s point of view, today reinforced concrete became one of the most evident means of the world developmen...

  10. Token reinforcement and resistance to change

    OpenAIRE

    Thrailkill, Eric A

    2013-01-01

    Interventions based on a token economy effectively reduce problematic behavior. Yet, treatment gains deteriorate once an intervention is discontinued. It is important to better understand the persistence of behavior maintained by token reinforcement in simple experimental procedures. A Pavlovian association with primary reinforcement is said to endow neutral stimuli (e.g., coins, poker chips, lights, signs, stickers, etc.) with their own function to strengthen behavior as conditioned reinforc...

  11. The mechanics of fibre-reinforced sand

    OpenAIRE

    Dos Santos, APS; Consoli, NC; Baudet, BA

    2010-01-01

    Fibres can be an effective means of reinforcing soils. This paper presents data from laboratory triaxial tests on quartzitic sand reinforced with polypropylene fibres. By keeping the studied composite consistent throughout the study (host sand and fibre characteristics kept constant), it has been possible to develop a framework of behaviour for the sand-fibre material, which provides a solid base for future research on fibre-reinforced soils. Data from previous work and from new tests have be...

  12. Behavior of reinforced concrete at elevated temperatures

    International Nuclear Information System (INIS)

    A study is presented concerning the behavior of reinforced concrete sections at elevated temperatures. Material properties of concrete and reinforcing steel are discussed. Behavior studies are made by means of moment-curvature-axial force relationships. Particular attention is given to the load carrying capacity, thermal forces and moments, and deformation capacity. The effects on these properties of variations in the strength properties, the temperature level and distribution, the amount of reinforcing steel, and limiting values of strains are considered

  13. Equivalence relations and the reinforcement contingency.

    OpenAIRE

    Sidman, M

    2000-01-01

    Where do equivalence relations come from? One possible answer is that they arise directly from the reinforcement contingency. That is to say, a reinforcement contingency produces two types of outcome: (a) 2-, 3-, 4-, 5-, or n-term units of analysis that are known, respectively, as operant reinforcement, simple discrimination, conditional discrimination, second-order conditional discrimination, and so on; and (b) equivalence relations that consist of ordered pairs of all positive elements that...

  14. Reinforcement learning in repeated portfolio decisions

    OpenAIRE

    Diao, Linan; Rieskamp, Jörg

    2011-01-01

    How do people make investment decisions when they receive outcome feedback? We examined how well the standard mean-variance model and two reinforcement models predict people's portfolio decisions. The basic reinforcement model predicts a learning process that relies solely on the portfolio's overall return, whereas the proposed extended reinforcement model also takes the risk and covariance of the investments into account. The experimental results illustrate that people reacted sensitively to...

  15. Fiber reinforced hybrid phenolic foam

    Science.gov (United States)

    Desai, Amit

    Hybrid composites in recent times have been developed by using more than one type of fiber reinforcement to bestow synergistic properties of the chosen filler and matrix and also facilitating the design of materials with specific properties matched to end use. However, the studies for hybrid foams have been very limited because of problems related to fiber dispersion in matrix, non uniform mixing due to presence of more than one filler and partially cured foams. An effective approach to synthesize hybrid phenolic foam has been proposed and investigated here. Hybrid composite phenolic foams were reinforced with chopped glass and aramid fibers in varied proportions. On assessing mechanical properties in compression and shear several interesting facts surfaced but overall hybrid phenolic foams exhibited a more graceful failure, greater resistance to cracking and were significantly stiffer and stronger than foams with only glass and aramid fibers. The optimum fiber ratio for the reinforced hybrid phenolic foam system was found to be 1:1 ratio of glass to aramid fibers. Also, the properties of hybrid foam were found to deviate from rule of mixture (ROM) and thus the existing theories of fiber reinforcement fell short in explaining their complex behavior. In an attempt to describe and predict mechanical behavior of hybrid foams a statistical design tool using analysis of variance technique was employed. The utilization of a statistical model for predicting foam properties was found to be an appropriate tool that affords a global perspective of the influence of process variables such as fiber weight fraction, fiber length etc. on foam properties (elastic modulus and strength). Similar approach could be extended to study other fiber composite foam systems such as polyurethane, epoxy etc. and doing so will reduce the number of experimental iterations needed to optimize foam properties and identify critical process variables. Diffusivity, accelerated aging and flammability

  16. Nonlinear Analysis of Reinforced Concrete Column with Fiber Reinforced Polymer Bars

    Directory of Open Access Journals (Sweden)

    T. Subramani

    2014-06-01

    Full Text Available In this paper, the results of an analytical investigation on the behaviour of RC columns reinforced with fibber reinforced polymer bars FRP are presented and discussed. Nonlinear finite element analysis on 10-column specimens was achieved by using ANSYS software. The nonlinear finite element analysis program ANSYS is utilized owing to its capabilities to predict either the response of reinforced concrete columns in the post-elastic range or the ultimate strength of a reinforced concrete columns reinforced by FRP bars. An extensive set of parameters is investigated including different main reinforcement ratios, main reinforcement types (GFRP, Steel, the transverse reinforcement ratios, and the characteristic compressive strength of concrete. A comparison between the experimental results and those predicted by the existing models are presented. Results and conclusions may be useful for designers, have been raised, and represented.

  17. Enhancing corrosion resistance of reinforced concrete structures with hybrid fiber reinforced concrete

    International Nuclear Information System (INIS)

    Highlights: • Reinforced concrete beams were subjected to cyclic flexural loading. • Hybrid fiber reinforced composites were effective in reducing corrosion rates. • Crack resistance due to fibers increased corrosion resistance of steel rebar. • Galvanic corrosion measurements underestimated corrosion rates. • Polarization resistance measurements predicted mass loss more accurately. - Abstract: Service loads well below the yield strength of steel reinforcing bars lead to cracking of reinforced concrete. This paper investigates whether the crack resistance of Hybrid Fiber Reinforced Concrete (HyFRC) reduces the corrosion rate of steel reinforcing bars in concrete after cyclic flexural loading. The reinforcing bars were extracted to examine their surface for corrosion and compare microcell and macrocell corrosion mass loss estimates against direct gravimetric measurements. A delay in corrosion initiation and lower active corrosion rates were observed in the HyFRC beam specimens when compared to reinforced specimens containing plain concrete matrices cycled at the same flexural load

  18. Mechanical characterization of fiber reinforced Polymer Concrete

    Directory of Open Access Journals (Sweden)

    João Marciano Laredo dos Reis

    2005-09-01

    Full Text Available A comparative study between epoxy Polymer Concrete plain, reinforced with carbon and glass fibers and commercial concrete mixes was made. The fibers are 6 mm long and the fiber content was 2% and 1%, respectively, in mass. Compressive tests were performed at room temperature and load vs. displacement curves were plotted up to failure. The carbon and glass fibers reinforcement were randomly dispersed into the matrix of polymer concrete. An increase in compressive properties was observed as function of reinforcement. The comparison also showed that Polymer Concrete, plain and reinforced, has a better performance than regular market concrete, suggesting that PC is a reliable alternative for construction industry.

  19. Effects of reinforcement history on responding under progressive-ratio schedules of reinforcement.

    OpenAIRE

    Cohen, S L; Pedersen, J.; Kinney, G G; Myers, J.

    1994-01-01

    The effects of experimental history on responding under a progressive-ratio schedule of reinforcement were examined. Sixteen pigeons were divided into four equal groups. Groups 1 to 3 were trained to peck a key for food under a fixed-ratio, variable-ratio, or differential-reinforcement-of-low-rate schedule of reinforcement. After training, these pigeons were shifted to a progressive-ratio schedule, later were shifted back to their original schedule (with decreased rates of reinforcement), and...

  20. DUCTILITY BEHAVIOR FIBER REINFORCED CONCRETE BEAMS STRENGTHENED WITH EXTERNALLY BONDED GLASS FIBER REINFORCED POLYMER LAMINATES

    OpenAIRE

    Mariappan Mahalingam; Ragunath Pulipakka Narashima Rao; Suguna Kannan

    2013-01-01

    The study presents the results of an experimental investigation conducted on Steel Fiber Reinforced Concrete (SFRC) beams with externally bonded Glass Fiber Reinforced Polymer (GFRP) laminates with a view to study their strength and ductility. A total of ten beams, 150Ã250 mm in cross-section were tested in the laboratory over an effective span of 2800 mm. Three fiber reinforced concrete beams were used as reference beams. Six fiber reinforced concrete beams were provided with externally bond...

  1. Strength Modeling of Reinforced Concrete Beam with Externally Bonded FRP Reinforcement

    OpenAIRE

    N. Pannirselvam; P. N. Ragunath; Suguna, K

    2008-01-01

    This research study presents the evaluation of the structural behaviour of reinforced concrete beams with externally bonded Fibre Reinforced Polymer (FRP) reinforcements. Three different steel ratios with two different Glass Fibre Reinforced Polymer (GFRP) types and two different thicknesses in each type of GFRP were used. Totally fifteen rectangular beams of 3 m length were cast. Three rectangular beams were used as reference beam (Control Beams) and the remaining were fixed with GFRP lamina...

  2. Nonlinear Analysis of Reinforced Concrete Column with Fiber Reinforced Polymer Bars

    OpenAIRE

    T.Subramani; Reni Kuruvilla

    2014-01-01

    In this paper, the results of an analytical investigation on the behaviour of RC columns reinforced with fibber reinforced polymer bars FRP are presented and discussed. Nonlinear finite element analysis on 10-column specimens was achieved by using ANSYS software. The nonlinear finite element analysis program ANSYS is utilized owing to its capabilities to predict either the response of reinforced concrete columns in the post-elastic range or the ultimate strength of a reinforced...

  3. MODELING THE EFFECTS OF SENSORY REINFORCERS ON BEHAVIORAL PERSISTENCE WITH ALTERNATIVE REINFORCEMENT

    OpenAIRE

    Sweeney, Mary M.; Moore, Keira; Shahan, Timothy A; Ahearn, William H; Dube, William V; Nevin, John A

    2014-01-01

    Problem behavior often has sensory consequences that cannot be separated from the target response, even if external, social reinforcers are removed during treatment. Because sensory reinforcers that accompany socially mediated problem behavior may contribute to persistence and relapse, research must develop analog sensory reinforcers that can be experimentally manipulated. In this research, we devised analogs to sensory reinforcers in order to control for their presence and determine how sens...

  4. The paradox of preference for unreliable reinforcement: The role of context and conditioned reinforcement

    OpenAIRE

    Lalli, Joseph S.; Mauro, Benjamin C

    1995-01-01

    We discuss Belke and Spetch's (1994) work on choice between reliable and unreliable reinforcement. The studies by Belke and Spetch extend a line of basic research demonstrating that under certain experimental conditions in a concurrent chains procedure, pigeons prefer an alternative that produces unreliable reinforcement. The authors describe the variables that influence preference for unreliable reinforcement, including the signaling and the duration of the reinforcement schedules, the conte...

  5. Noncontingent Reinforcement, Alternative Reinforcement, and the Matching Law: A Laboratory Demonstration

    Science.gov (United States)

    Ecott, Cheryl L.; Critchfield, Thomas S.

    2004-01-01

    Basic researchers, but not most applied researchers, have assumed that the behavior-decelerating effects of noncontingent reinforcement result at least partly from adventitious reinforcement of competing behaviors. The literature contains only sketchy evidence of these effects because few noncontingent reinforcement studies measure alternative…

  6. Reinforcement Delay Fading during Differential Reinforcement of Communication: The Effects of Signals on Response Maintenance

    Science.gov (United States)

    Kelley, Michael E.; Lerman, Dorothea C.; Fisher, Wayne W.; Roane, Henry S.; Zangrillo, Amanda N.

    2011-01-01

    Signals during delays to reinforcement may lessen reductions in responding that typically occur when there is a delay between a response and its reinforcer. Sparse applied research has been devoted to understanding the conditions under which responding may be maintained when delays to reinforcement are introduced. We evaluated the extent to which…

  7. Reinforcement learning or active inference?

    Science.gov (United States)

    Friston, Karl J; Daunizeau, Jean; Kiebel, Stefan J

    2009-01-01

    This paper questions the need for reinforcement learning or control theory when optimising behaviour. We show that it is fairly simple to teach an agent complicated and adaptive behaviours using a free-energy formulation of perception. In this formulation, agents adjust their internal states and sampling of the environment to minimize their free-energy. Such agents learn causal structure in the environment and sample it in an adaptive and self-supervised fashion. This results in behavioural policies that reproduce those optimised by reinforcement learning and dynamic programming. Critically, we do not need to invoke the notion of reward, value or utility. We illustrate these points by solving a benchmark problem in dynamic programming; namely the mountain-car problem, using active perception or inference under the free-energy principle. The ensuing proof-of-concept may be important because the free-energy formulation furnishes a unified account of both action and perception and may speak to a reappraisal of the role of dopamine in the brain. PMID:19641614

  8. Reinforcement learning or active inference?

    Directory of Open Access Journals (Sweden)

    Karl J Friston

    Full Text Available This paper questions the need for reinforcement learning or control theory when optimising behaviour. We show that it is fairly simple to teach an agent complicated and adaptive behaviours using a free-energy formulation of perception. In this formulation, agents adjust their internal states and sampling of the environment to minimize their free-energy. Such agents learn causal structure in the environment and sample it in an adaptive and self-supervised fashion. This results in behavioural policies that reproduce those optimised by reinforcement learning and dynamic programming. Critically, we do not need to invoke the notion of reward, value or utility. We illustrate these points by solving a benchmark problem in dynamic programming; namely the mountain-car problem, using active perception or inference under the free-energy principle. The ensuing proof-of-concept may be important because the free-energy formulation furnishes a unified account of both action and perception and may speak to a reappraisal of the role of dopamine in the brain.

  9. Polymer nanocomposites reinforced with montmorillonite

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2012-01-01

    Full Text Available Purpose: Light microscope with polarized light has been used for observation layered zone, visible thanks to polarization of the light, inside polymer-polymer composites and nanocomposites Aim of work has been concentrated on investigation of nanocomposites as promising engineering materials, basing on composition of polypropylene and montmorillonite as reinforcement in the shape of nanoparticles of 2:1 silicate.Design/methodology/approach: Conventional and non-conventional injection molding process has been used for obtaining nanocomposites. In non-conventional process has been used the special mold for inducing the shear rates, additionally equipped with external computer to control melt manipulation of solidifying polymer inside mold cavityFindings: Highly developed structure consisted of multilayer zone between skin and core mainly responsible for reinforcement and improvement of fracture toughness of polymer composites and nanocompositesResearch limitations/implications: Nanocomposites of polymer blends and montmorillonite were moulded by direct injection moulding according to melt temperature and stroke time-number combination included in design of experiments.Practical implications: Application of special injection moulding technique provides to structure development and gives possibility to create multilayer zone, which strengthen material. Besides strengthening obtaining of such nanocomposites is cheap thanks to application of low cost injection moulding technique and not expensive polyolefines with developed structure, without using additional fillers (e.g. compatybilizers.Originality/value: Very wide application of polymer composites and nanocomposites as engineering materials used for various industries like building engineering, automotive and aerospace

  10. Structural Behavior of Concrete Beams Reinforced with Basalt Fiber Reinforced Polymer (BFRP) Bars

    Science.gov (United States)

    Ovitigala, Thilan

    The main challenge for civil engineers is to provide sustainable, environmentally friendly and financially feasible structures to the society. Finding new materials such as fiber reinforced polymer (FRP) material that can fulfill the above requirements is a must. FRP material was expensive and it was limited to niche markets such as space shuttles and air industry in the 1960s. Over the time, it became cheaper and spread to other industries such as sporting goods in the 1980-1990, and then towards the infrastructure industry. Design and construction guidelines are available for carbon fiber reinforced polymer (CFRP), aramid fiber reinforced polymer (AFRP) and glass fiber reinforced polymer (GFRP) and they are currently used in structural applications. Since FRP is linear elastic brittle material, design guidelines for the steel reinforcement are not valid for FRP materials. Corrosion of steel reinforcement affects the durability of the concrete structures. FRP reinforcement is identified as an alternative to steel reinforcement in corrosive environments. Although basalt fiber reinforced polymer (BFRP) has many advantages over other FRP materials, but limited studies have been done. These studies didn't include larger BFRP bar diameters that are mostly used in practice. Therefore, larger beam sizes with larger BFRP reinforcement bar diameters are needed to investigate the flexural and shear behavior of BFRP reinforced concrete beams. Also, shear behavior of BFRP reinforced concrete beams was not yet studied. Experimental testing of mechanical properties and bond strength of BFRP bars and flexural and shear behavior of BFRP reinforced concrete beams are needed to include BFRP reinforcement bars in the design codes. This study mainly focuses on the use of BFRP bars as internal reinforcement. The test results of the mechanical properties of BFRP reinforcement bars, the bond strength of BFRP reinforcement bars, and the flexural and shear behavior of concrete beams

  11. 3D textiles for composite reinforcements

    OpenAIRE

    Fangueiro, Raúl; Mingxing, Z.; Hong, H; Soutinho, Hélder Filipe Cunha; Gonçalves, P.; Araújo, Mário Duarte de

    2010-01-01

    This paper presents an overview on the last developments on 3D textile structures for composite reinforcements. The application of innovative 3D shaped weft-knitted preforms in GFRP tube joints is presented and discussed. Moreover, the mechanical behaviour of 3D hybrid basalt fiber reinforced composite material sis also presented and discussed.

  12. Token Reinforcement: A Review and Analysis

    Science.gov (United States)

    Hackenberg, Timothy D.

    2009-01-01

    Token reinforcement procedures and concepts are reviewed and discussed in relation to general principles of behavior. The paper is divided into four main parts. Part I reviews and discusses previous research on token systems in relation to common behavioral functions--reinforcement, temporal organization, antecedent stimulus functions, and…

  13. Durability of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard

    The planned research will indicate, whether fibre reinforced concrete has better or worse durability than normal concrete. Durability specimens will be measured on cracked as well as uncracked specimens. Also the pore structure in the concrete will be characterized.Keywords: Fibre reinforced...... concrete, durability, pore structure, mechanical load...

  14. Design guidelines for FRP reinforced concrete structures

    OpenAIRE

    Pilakoutas, Kypros; Guadagnini, Maurizio; Neocleous, Kyriacos; Matthys, Stijn

    2011-01-01

    This paper presents an outline of the approach proposed by fib task group 9.3 for the next generation of design guidelines for fibre-reinforced polymer (FRP) reinforced concrete structures. The approach covers a range of FRP-related topics, including material properties, durability, design philosophy, the limit states of bending, shear, cracking and deflection, and bond.

  15. Operant Variability and the Power of Reinforcement

    Science.gov (United States)

    Neuringer, Allen

    2009-01-01

    Reinforcers contingent on response variability exert powerful and precise control over levels of variability, from stereotypy to stochasticity. This paper reviews how variability-contingent reinforcers interact with non-contingent, eliciting events to influence the variability of operant responses. Relationships to stimulus control, choice,…

  16. Demonstrating Differential Reinforcement by Shaping Classroom Participation.

    Science.gov (United States)

    Hodge, Gordon K.; Nelson, Nancy H.

    1991-01-01

    Describes a classroom demonstration using differential reinforcement to shape student participation in a small psychology laboratory. Concludes that the technique was useful for illustrating how reinforcers shape behavior. Suggests that the demonstration facilitated understanding of operant conditioning procedures and encouraged more equitable…

  17. A survey of random processes with reinforcement

    OpenAIRE

    Pemantle, Robin

    2006-01-01

    The models surveyed include generalized P\\'{o}lya urns, reinforced random walks, interacting urn models, and continuous reinforced processes. Emphasis is on methods and results, with sketches provided of some proofs. Applications are discussed in statistics, biology, economics and a number of other areas.

  18. Fatigue Performance of Fiber Reinforced Concrete

    DEFF Research Database (Denmark)

    Jun, Zhang; Stang, Henrik

    1996-01-01

    The objective of the present study is to obtain basic data of fibre reinforced concrete under fatigue load and to set up a theoretical model based on micromechanics. In this study, the bridging stress in fiber reinforced concrete under cyclic tensile load was investigted in details. The damage...

  19. Mechanism Analysis of Helical and Twisted Reinforcement

    Institute of Scientific and Technical Information of China (English)

    ZHANG Junlin; ZHOU Bo

    2008-01-01

    Although helical and twisted reinforcement has been used to reinforce concrete for more than two decades,its rationale still remains unclear.With a brief review of current researches on the helical and twisted reinforcement properties,this paper describes some new phenomenon of the helical and twisted reinforcement in concrete and other matrix by experimental studies,and then discusses on mechanism of helical effect of strengthening.This paper also discusses the mechanism of accessional helical effect of strengthening and its significance in industrial practice.Extensive tests indicate that twisting is the most effective way to improve reinforcement mechanical properties.The main results are:(1)They can greatly enhance bond anchorage in base material.In some pull-out tests,the pull-out resistance increases with reinforcement slip within the specimens,which results not only in a higher pull-out load but also a larger slip up to 70%-80% of reinforcement embedded length.(2)Concrete reinforced by twisted bars demonstrates certain ductility at failure.(3)The bond strength depends on the pitch space directly.(4)The twisted effect on material strengthening is from a three-dimensional interlocking force which is formed from material untwisting when they were pulled out from base specimens.

  20. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS

    International Nuclear Information System (INIS)

    This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits

  1. Reinforcement Learning State-of-the-Art

    CERN Document Server

    Wiering, Marco

    2012-01-01

    Reinforcement learning encompasses both a science of adaptive behavior of rational beings in uncertain environments and a computational methodology for finding optimal behaviors for challenging problems in control, optimization and adaptive behavior of intelligent agents. As a field, reinforcement learning has progressed tremendously in the past decade. The main goal of this book is to present an up-to-date series of survey articles on the main contemporary sub-fields of reinforcement learning. This includes surveys on partially observable environments, hierarchical task decompositions, relational knowledge representation and predictive state representations. Furthermore, topics such as transfer, evolutionary methods and continuous spaces in reinforcement learning are surveyed. In addition, several chapters review reinforcement learning methods in robotics, in games, and in computational neuroscience. In total seventeen different subfields are presented by mostly young experts in those areas, and together the...

  2. Online learning control by association and reinforcement.

    Science.gov (United States)

    Si, J; Wang, Y T

    2001-01-01

    This paper focuses on a systematic treatment for developing a generic online learning control system based on the fundamental principle of reinforcement learning or more specifically neural dynamic programming. This online learning system improves its performance over time in two aspects: 1) it learns from its own mistakes through the reinforcement signal from the external environment and tries to reinforce its action to improve future performance; and 2) system states associated with the positive reinforcement is memorized through a network learning process where in the future, similar states will be more positively associated with a control action leading to a positive reinforcement. A successful candidate of online learning control design is introduced. Real-time learning algorithms is derived for individual components in the learning system. Some analytical insight is provided to give guidelines on the learning process took place in each module of the online learning control system. PMID:18244383

  3. Carbon nanofibre reinforcement of soft materials

    International Nuclear Information System (INIS)

    In elastomeric matrices carbon nanofibres are found to be twenty times more effective than carbon black as a reinforcing filler. In hard matrices, by contrast, reinforcement is minimal. Tensile and dynamic mechanical tests were performed to elucidate the mechanism of reinforcement in order to explain the superior performance in soft matrices. Small-angle neutron scattering and ultra-small-angle X-ray scattering were used to quantify filler morphology, which turns out to be the key factor that limits reinforcement potential. The presence of fractal cluster formed by agglomeration of the nanofibres reduces the effective aspect ratio of the nanotubes. Clustering, however, introduces a new reinforcement mechanism based on elastic deformation of the fibre clusters. This mechanism is operative in soft matrices but not in hard matrices, thus explaining the enhanced performance in soft matrices.

  4. Modeling the effects of sensory reinforcers on behavioral persistence with alternative reinforcement.

    Science.gov (United States)

    Sweeney, Mary M; Moore, Keira; Shahan, Timothy A; Ahearn, William H; Dube, William V; Nevin, John A

    2014-09-01

    Problem behavior often has sensory consequences that cannot be separated from the target response, even if external, social reinforcers are removed during treatment. Because sensory reinforcers that accompany socially mediated problem behavior may contribute to persistence and relapse, research must develop analog sensory reinforcers that can be experimentally manipulated. In this research, we devised analogs to sensory reinforcers in order to control for their presence and determine how sensory reinforcers may impact treatment efficacy. Experiments 1 and 2 compared the efficacy of differential reinforcement of alternative behavior (DRA) versus noncontingent reinforcement (NCR) with and without analog sensory reinforcers in a multiple schedule. Experiment 1 measured the persistence of key pecking in pigeons, whereas Experiment 2 measured the persistence of touchscreen responses in children with intellectual and developmental disabilities. Across both experiments, the presence of analog sensory reinforcers increased the levels, persistence, and variability of responding relative to when analog sensory reinforcers were absent. Also in both experiments, target responding was less persistent under conditions of DRA compared to NCR regardless of the presence or absence of analog sensory reinforcers. PMID:25130416

  5. DUCTILITY BEHAVIOR FIBER REINFORCED CONCRETE BEAMS STRENGTHENED WITH EXTERNALLY BONDED GLASS FIBER REINFORCED POLYMER LAMINATES

    Directory of Open Access Journals (Sweden)

    Mariappan Mahalingam

    2013-01-01

    Full Text Available The study presents the results of an experimental investigation conducted on Steel Fiber Reinforced Concrete (SFRC beams with externally bonded Glass Fiber Reinforced Polymer (GFRP laminates with a view to study their strength and ductility. A total of ten beams, 150×250 mm in cross-section were tested in the laboratory over an effective span of 2800 mm. Three fiber reinforced concrete beams were used as reference beams. Six fiber reinforced concrete beams were provided with externally bonded GFRP laminates. One concrete beam was left virgin without any fiber reinforcement and external GFRP laminates. All the beams were tested until failure. The variables considered included volume fraction of fiber reinforcement and stiffness of GFRP laminates. The static responses of all the beams were evaluated in terms of strength, stiffness and ductility. The test results show that the beams provided with externally bonded GFRP laminates exhibit improved performance over the beams with internal fiber reinforcement.

  6. Failure Criteria for Reinforced Materials

    DEFF Research Database (Denmark)

    Rathkjen, Arne

    Failure of materials is often characterized as ductile yielding, brittle fracture, creep rupture, etc., and different criteria given in terms of different parameters have been used to describe different types of failure. Only criteria expressing failure in terms of stress are considered in what...... place until the matrix, the continuous component of the composite, fails. When an isotropic matrix is reinforced as described above, the result is an anisotropic composite material. Even if the material is anisotropic, it usually exhibits a rather high degree of symmetry and such symmetries place...... certain restrictions on the form of the failure criteria for anisotropic materials. In section 2, some failure criteria for homogenous materials are reviewed. Both isotropic and anisotropic materials are described, and in particular the constraints imposed on the criteria from the symmetries orthotropy...

  7. Bayesian multitask inverse reinforcement learning

    CERN Document Server

    Dimitrakakis, Christos

    2011-01-01

    We generalise the problem of inverse reinforcement learning to multiple tasks, from a set of demonstrations. Each demonstration may represent one expert trying to solve a different task. Alternatively, one may see each demonstration as given by a different expert trying to solve the same task. Our main technical contribution is to solve the problem by formalising it as statistical preference elicitation, via a number of structured priors, whose form captures our biases about the relatedness of different tasks or expert policies. We show that our methodology allows us not only to learn to efficiently from multiple experts but to also effectively differentiate between the goals of each. Possible applications include analysing the intrinsic motivations of subjects in behavioural experiments and imitation learning from multiple teachers.

  8. Natural Fibre-Reinforced Biofoams

    Directory of Open Access Journals (Sweden)

    Anne Bergeret

    2011-01-01

    Full Text Available Starches and polylactic acids (PLAs represent the main biobased and biodegradable polymers with potential industrial availability in the next decades for “bio” foams applications. This paper investigates the improvement of their morphology and properties through processing and materials parameters. Starch foams were obtained by melt extrusion in which water is used as blowing agent. The incorporation of natural fibres (hemp, cellulose, cotton linter, sugarcane, coconut in the starch foam induced a density reduction up to 33%, a decrease in water absorption, and an increase in mechanical properties according to the fibre content and nature. PLA foams were obtained through single-screw extrusion using of a chemical blowing agent that decomposed at the PLA melting temperature. A void content of 48% for PLA and 25% for cellulose fibre-reinforced PLA foams and an improvement in mechanical properties were achieved. The influence of a fibre surface treatment was investigated for both foams.

  9. Systematic reinforcement: academic performance of underachieving students.

    Science.gov (United States)

    Chadwick, B A; Day, R C

    1971-01-01

    The effect of contingent tangible and social reinforcement on academic performance was investigated in an experimental classroom of 25 selected underachieving students. Measures were taken of both teacher and child behavior during a baseline and two experimental treatment periods. During Treatment I, a point system with tangible backup reinforcers was combined with contingent social reinforcers dispensed by the teaching staff to assess the effects on three measures of academic performance (i.e., per cent of time at work, work output per minute, and accuracy). During Treatment II, the contingencies for the tangible reinforcers were terminated while social reinforcement was continued to see if the positive effects of Treatment I on academic performance would persist. The results show that with combined tangible and social reinforcers, students' work time, rate of output per hour, and accuracy in all activities substantially increased. After termination of the tangible reinforcers, the students maintained their high rates of output per hour and accuracy for the remaining period of the study while the total amount of time at work returned to the baseline level. PMID:16795308

  10. Theoretical Analysis of Reinforcement Tunnel Lining Corrosion

    Directory of Open Access Journals (Sweden)

    ZhiQiang Zhangand

    2013-05-01

    Full Text Available The main cause of ageing damage in reinforced concrete structures is reinforcement corrosion. Damage can be detected visually as coincident cracks along the reinforcement bar, which are significant of both reduction of the re-bar, cross-section and loss of bond strength for reinforced concrete. The reinforced concrete is one of the most widely used engineering materials as final lining of tunnels. The corrosion is common durability problems that have significant effect on the tunnel performance. This study intends to analysis reinforcement concrete corrosion at the tunnel lining by applying temperature expansion theory on steel through numerical simulation process, with expansive force effect. The thickness of concrete cover and the diameter of steel bar have an impact on the stress for reinforcement concrete during propagation of corrosion process. The corrosion cracks appear at the corner of a tunnel lining then in invert and vault because the maximum stress will be in the corner then in invert and vault. The internal force in the concrete lining changes differently when the corrosion rate change.

  11. Damage tolerance analysis of aircraft reinforced panels

    Directory of Open Access Journals (Sweden)

    A. Pirondi

    2011-04-01

    Full Text Available This work is aimed at reproducing numerically a campaign of experimental tests performed for the development of reinforced panels, typically found in aircraft fuselage. The bonded reinforcements can significantly reduce the rate of fatigue crack growth and increase the residual strength of the skin. The reinforcements are of two types: stringers and doublers. The former provides stiffening to the panel while the latter controls the crack growth between the stringers. The purpose of the study is to validate a numerical method of analysis that can predict the damage tolerance of these reinforced panels. Therefore, using a fracture mechanics approach, several models (different by the geometry and the types of reinforcement constraints were simulated with the finite element solver ABAQUS. The bonding between skin and stiffener was taken either rigid or flexible due to the presence of adhesive. The possible rupture of the reinforcements was also considered. The stress intensity factor trend obtained numerically as a function of crack growth was used to determine the fatigue crack growth rate, obtaining a good approximation of the experimental crack propagation rate in the skin. Therefore, different solutions for improving the damage tolerance of aircraft reinforced panels can be virtually tested in this way before performing experiments.

  12. Analysis of reactive stress in concrete reinforcement of reinforced concrete blocks joined with pressed joints

    International Nuclear Information System (INIS)

    The possible replacement was considered of welded joints on concrete reinforcements in rigid structures by pressed sleeve joints. The effects on inner stress of joint reinforced concrete blocks were compared. A laboratory test was performed aimed at establishing the size and the course of stress induced in the models of reinforced concrete block structures by the sleeve joints of the individual reinforcements. Static calculations were carried out of stress and deformation of the spatial rod structure consisting of two extreme models of reinforced concrete blocks, loaded with longitudinal rod deformation in pressed sleeve joint points. The magnetoelastic method was used in testing stress in the reinforcement. Models are described for the laboratory tests and the measured and the calculated values are listed of reactive stress in the rods. The measurements and the calculations showed that the method of anchoring the reinforcement in the reinforced concrete structure significantly affects the magnitude of stress. It was shown that the welded joint with an experimentally observed free shrinkage of about 0.8 mm exerted a similar effect on the stress of the reinforcement like the pressed joint. Pressed joint sleeves can be used in the design of reinforced concrete blocks for the Mochovce nuclear power plant. (J.B.). 9 figs., 3 tabs., 4 refs

  13. Optimal reinforcing of reticular structures Optimal reinforcing of reticular structures

    Directory of Open Access Journals (Sweden)

    Juan Santiago Mejía

    2006-12-01

    Full Text Available This article presents an application of Genetic Algorithms (GA and Finite Element Analysis (FEA to solve a structural optimisation problem on reticular plastic structures. Structural optimisation is used to modify the original shape by placing reinforcements at optimum locations. As a result, a reduction in the maximum stress by 14,70% for a structure with a final volume increase of 8,36% was achieved. This procedure solves the structural optimisation problem by adjusting the original mold and thereby avoiding the re-construction of a new one.Este artículo presenta una aplicación de Algoritmos Genéticos (GA y Análisis por Elementos Finitos (FEA a la solución de un problema de optimización estructural en estructuras reticulares plásticas. Optimización estructurales usada para modificar la forma original colocando refuerzos en posiciones óptimas. Como resultado se obtuvo una reducción en el esfuerzo máximo de 14,70% para una estructura cuyo volumen original aumento en 8,36%. Este procedimiento soluciona el problema de optimización estructural ajustando el molde original y evitando la manufactura de un nuevo molde.

  14. FOAM CONCRETE REINFORCEMENT BY BASALT FIBRES

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2012-10-01

    Full Text Available The authors demonstrate that the foam concrete performance can be improved by dispersed reinforcement, including methods that involve basalt fibres. They address the results of the foam concrete modeling technology and assess the importance of technology-related parameters. Reinforcement efficiency criteria are also provided in the article. Dispersed reinforcement improves the plasticity of the concrete mix and reduces the settlement crack formation rate. Conventional reinforcement that involves metal laths and rods demonstrates its limited application in the production of concrete used for thermal insulation and structural purposes. Dispersed reinforcement is preferable. This technology contemplates the infusion of fibres into porous mixes. Metal, polymeric, basalt and glass fibres are used as reinforcing components. It has been identified that products reinforced by polypropylene fibres demonstrate substantial abradability and deformability rates even under the influence of minor tensile stresses due to the low adhesion strength of polypropylene in the cement matrix. The objective of the research was to develop the type of polypropylene of D500 grade that would demonstrate the operating properties similar to those of Hebel and Ytong polypropylenes. Dispersed reinforcement was performed by the basalt fibre. This project contemplates an autoclave-free technology to optimize the consumption of electricity. Dispersed reinforcement is aimed at the reduction of the block settlement in the course of hardening at early stages of their operation, the improvement of their strength and other operating properties. Reduction in the humidity rate of the mix is based on the plasticizing properties of fibres, as well as the application of the dry mineralization method. Selection of optimal parameters of the process-related technology was performed with the help of G-BAT-2011 Software, developed at Moscow State University of Civil Engineering. The authors also

  15. Working mechanism of two-direction reinforced composite foundation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ling; ZHAO Ming-hua; HE Wei

    2007-01-01

    Based on the discussion about working mechanism of horizontal reinforcement and that of vertical reinforcement,respectively, the working mechanism of two-direction reinforced composite foundation was studied. The enhancing effect of horizontal reinforcement on vertical reinforced composite foundation was analyzed. A simplified calculation method for such two-direction reinforced working system was presented. A model experiment was carried out to validate the proposed method. In the experiment, geocell reinforcement worked as the horizontal reinforcement, while gravel pile composite foundation worked as the vertical reinforcement. The results show that the calculated curve is close to the measured one. The installation of geosynthetic reinforcement can increase the bearing capacity of composite foundation by nearly 68% at normal foundation settlement, which suggests that the enhancing effect by geosynthetic reinforcement should be taken into account in current design/analysis methods.

  16. Effects of RC beams reinforcement using near surface mounted reinforced FRP composites

    Directory of Open Access Journals (Sweden)

    Ranković Slobodan

    2010-01-01

    Full Text Available This paper analyzes application of modern reinforcement methods for reinforced concrete (RC beams using fiber-reinforced polymer (FRP materials. Basic characteristics of FRP materials and the method of mounting the FRP bars within concrete, that is, near the surface of the beams (NSM method are presented. The properties of this method and its advantages in comparison to externally bonded reinforcement laminate method (EBR have been analyzed. The results of measured deflections and width of the cracks of the beams reinforced by FRP bars, depending on the load are presented and discussed, in comparison to the results obtained from the non-reinforced beams. The experimental research was published at the Faculty of Civil Engineering and Architecture of Niš in 2009.

  17. Elastomer Reinforced with Carbon Nanotubes

    Science.gov (United States)

    Hudson, Jared L.; Krishnamoorti, Ramanan

    2009-01-01

    Elastomers are reinforced with functionalized, single-walled carbon nanotubes (SWNTs) giving them high-breaking strain levels and low densities. Cross-linked elastomers are prepared using amine-terminated, poly(dimethylsiloxane) (PDMS), with an average molecular weight of 5,000 daltons, and a functionalized SWNT. Cross-link densities, estimated on the basis of swelling data in toluene (a dispersing solvent) indicated that the polymer underwent cross-linking at the ends of the chains. This thermally initiated cross-linking was found to occur only in the presence of the aryl alcohol functionalized SWNTs. The cross-link could have been via a hydrogen-bonding mechanism between the amine and the free hydroxyl group, or via attack of the amine on the ester linage to form an amide. Tensile properties examined at room temperature indicate a three-fold increase in the tensile modulus of the elastomer, with rupture and failure of the elastomer occurring at a strain of 6.5.

  18. Ensemble algorithms in reinforcement learning.

    Science.gov (United States)

    Wiering, Marco A; van Hasselt, Hado

    2008-08-01

    This paper describes several ensemble methods that combine multiple different reinforcement learning (RL) algorithms in a single agent. The aim is to enhance learning speed and final performance by combining the chosen actions or action probabilities of different RL algorithms. We designed and implemented four different ensemble methods combining the following five different RL algorithms: Q-learning, Sarsa, actor-critic (AC), QV-learning, and AC learning automaton. The intuitively designed ensemble methods, namely, majority voting (MV), rank voting, Boltzmann multiplication (BM), and Boltzmann addition, combine the policies derived from the value functions of the different RL algorithms, in contrast to previous work where ensemble methods have been used in RL for representing and learning a single value function. We show experiments on five maze problems of varying complexity; the first problem is simple, but the other four maze tasks are of a dynamic or partially observable nature. The results indicate that the BM and MV ensembles significantly outperform the single RL algorithms. PMID:18632380

  19. Reinforcement learning in market games

    CERN Document Server

    Piotrowski, Edward W; Szczypinska, Anna

    2007-01-01

    Financial markets investors are involved in many games -- they must interact with other agents to achieve their goals. Among them are those directly connected with their activity on markets but one cannot neglect other aspects that influence human decisions and their performance as investors. Distinguishing all subgames is usually beyond hope and resource consuming. In this paper we study how investors facing many different games, gather information and form their decision despite being unaware of the complete structure of the game. To this end we apply reinforcement learning methods to the Information Theory Model of Markets (ITMM). Following Mengel, we can try to distinguish a class $\\Gamma$ of games and possible actions (strategies) $a^{i}_{m_{i}}$ for $i-$th agent. Any agent divides the whole class of games into analogy subclasses she/he thinks are analogous and therefore adopts the same strategy for a given subclass. The criteria for partitioning are based on profit and costs analysis. The analogy classe...

  20. Strengthening of reinforced concrete circular columns using glass fibre reinforced polymers

    OpenAIRE

    Manish kumar Tiwari; Rajiv Chandak

    2014-01-01

    Seismic retrofitting of reinforced concrete members vulnerable to strong earthquakes is a great problem. It has long been recognized that confinement to concrete compression members not only increase the strength but improve ductility significantly. The present study focuses on the behavior of reinforced concrete specimens strengthened using glass fiber reinforced polymer (GFRP) subjected to axial compressive loading. In this study specimen of circular cross section having len...

  1. Effects of the Reinforcement Morphology on the Fatigue Properties of Hydroxyapatite Reinforced Polymers

    OpenAIRE

    Kane, Robert J.; Converse, Gabriel L.; Roeder, Ryan K.

    2008-01-01

    The objective of this study was to examine the effects of the hydroxyapatite (HA) reinforcement morphology and content on the fatigue behavior of HA reinforced high density polyethylene (HDPE). To this end, HDPE was reinforced with 20 and 40 vol% of either HA whiskers or an equiaxed HA powder, and tested in four-point bending fatigue under simulated physiological conditions. The fatigue life, mechanical property degradation and failure surfaces were compared between experimental groups. HDPE ...

  2. Reinforcement Toolbox, a Parametric Reinforcement Modelling Tool for Curved Surface Structures

    OpenAIRE

    Lauppe, J.; Rolvink, A.; Coenders, J.L.

    2013-01-01

    This paper presents a computational strategy and parametric modelling toolbox which aim at enhancing the design- and production process of reinforcement in freeform curved surface structures. The computational strategy encompasses the necessary steps of raising an architectural curved surface model of a concrete building to production level in terms of reinforcement. The Reinforcement Toolbox supports this strategy by offering structural engineers and other professionals in the building indus...

  3. Glass fiber reinforced polymer bars as top mat reinforcement for bridge decks

    OpenAIRE

    J.M. DeFreese; Roberts-Wollmann, Carin L.

    2002-01-01

    The objectives of this research were to characterize the material and bond properties of three commercially available GFRP (glass fiber reinforced polymer) reinforcing bars, and evaluate the effects of the material properties and the current ACI design recommendations (ACI 2001) on the design of a bridge deck with GFRP as top mat reinforcement. The tensile properties evaluated were ultimate tensile strength, tensile modulus of elasticity and ultimate rupture strain. Ultimate bond stress and l...

  4. Continuous jute fibre reinforced laminated paper composite and reinforcement-fibre free paper laminate

    Indian Academy of Sciences (India)

    B B Verma

    2009-12-01

    Plastic bags create a serious environmental problem. The proposed jute fibre reinforced laminated paper composite and reinforcement-fibre free paper laminate may help to combat the war against this pollutant to certain extent. The paper laminate, without reinforcement fibre, exhibited a few fold superiority in tensile properties than single paper strip. The studies further show that an appreciable improvement in tensile properties can be achieved by introducing continuous jute fibre in paper laminates.

  5. Finite element modeling of reinforced concrete beams with a hybrid combination of steel and aramid reinforcement

    International Nuclear Information System (INIS)

    Highlights: • Modeling of concrete beams reinforced steel and FRP bars. • Developed finite element models achieved good results. • The models are validated via comparison with experimental results. • Parametric studies are performed. - Abstract: Corrosion of steel bars has an adverse effect on the life-span of reinforced concrete (RC) members and is usually associated with crack development in RC beams. Fiber reinforced polymer (FRP) bars have been recently used to reinforce concrete members in flexure due to their high tensile strength and superior corrosion resistance properties. However, FRP materials are brittle in nature, thus RC beams reinforced with such materials would exhibit a less ductile behavior when compared to similar members reinforced with conventional steel reinforcement. Recently, researchers investigated the performance of concrete beams reinforced with a hybrid combination of steel and Aramid Fiber Reinforced Polymer (AFRP) reinforcement to maintain a reasonable level of ductility in such members. The function of the AFRP bars is to increase the load-carrying capacity, while the function of the steel bars is to ensure ductility of the flexural member upon yielding in tension. This paper presents a three-dimensional (3D) finite element (FE) model that predicted the load versus mid-span deflection response of tested RC beams conducted by other researchers with a hybrid combination of steel and AFRP bars. The developed FE models account for the constituent material nonlinearities and bond–slip behavior between the reinforcing bars and adjacent concrete surfaces. It was concluded that the developed models can accurately capture the behavior and predicts the load-carrying capacity of such RC members. In addition, a parametric study is conducted using the validated models to investigate the effect of AFRP bar size, FRP material type, bond–slip action, and concrete compressive strength on the performance of concrete beams when reinforced

  6. Modeling of geosynthetic reinforced capping systems

    Energy Technology Data Exchange (ETDEWEB)

    Viswanadham, B.V.S.; Koenig, D.; Jessberger, H.L. [Univ. of Bochum (Germany)

    1997-12-31

    The investigation deals with the influence of a geosynthetic reinforcement on the deformation behavior and sealing efficiency of the reinforced mineral sealing layer at the onset of non-uniform settlements. The research program is mainly concentrated in studying the influence of reinforcement inclusion in restraining cracks and crack propagation due to soil-geosynthetic bond efficiency. Centrifuge model tests are conducted in the 500 gt capacity balanced beam Bochum geotechnical Centrifuge (Z1) simulating a differential deformation of a mineral sealing layer of a landfill with the help of trap-door arrangement. By comparing the performance of the deformed mineral sealing layer with and without geogrid, the reinforcement ability of the geogrid in controlling the crack propagation and permeability of the mineral swing layer is evaluated.

  7. Ductility of Reinforced Concrete Structures in Flexure

    DEFF Research Database (Denmark)

    Hestbech, Lars

    2013-01-01

    In this thesis, a rotational capacity model for flexural reinforced concrete elements is presented. The model is based on the general assumption, that any other failure mode than bending is prevented by proper design. This includes failure due to shear, anchorage, concentrated loads etc. Likewise......, beams governed by failure described by Kani’s Valley are not covered by the presented model. Hence, the model is delimited to shear reinforced elements failing in flexure. The rotational capacity model is divided into the following calculation procedures. 1. A cross sectional analysis of the critical...... section to obtain the maximum force in the tension reinforcement. 2. The variation of tensile forces in the reinforcement is determined from two contributions, moment and tension shift. 3. Correction of the tension force curve to tension stiffening effects. 4. Calculation of the rotational capacity by...

  8. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    fibre reinforcement are exposed to a combination of mechanical and environmental load to indicate whether fibre reinforcement will improve the durability of cracked concrete structures. Secondly, it is the aim to identify important mechanisms for the effect of the fibre reinforcement on the durability......Durability studies are carried out at BKM as part of the research project "Design Methods for Fibre Reinforced Concrete" (FRC) involving BKM, The Concrete Research Center at DTI, Building Technology at Aalborg University, Rambøll, 4K-Beton and Rasmussen & Schiøtz. Concrete beams with or without...... pore structure are made on specimens drilled or sawed from beams after unloading (mechanical load). The pore structure of the concretes will be studied by microscopy, sorption and suction curves. The test programme involves three different concrete qualities (water-cement ratios). Both steel fibres (ZP...

  9. Rotational Capacity of Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Ulfkjær, J. P.; Henriksen, M. S.; Brincker, Rune;

    1995-01-01

    The European Structural Integrity Society-Technical Committee 9, has initiated a Round Robin on 'Scale Effects and Transitional Failure Phenomena of Reinforced Concrete Beams in Flexure'. In Denmark, Aalborg University is participating. The programme for Aalborg University involves an experimental...... programme where 120 reinforced concrete beams, 54 plain concrete beams and 324 concrete cylinders are tested. For the reinforced concrete beams four different parar meters are varied. The slenderness is 6, 12 and 18, the beam depth is 100 mm, 200 mm and 400 mm giving nine different geometries, five...... reinforcement ratios between 0.14% and 1.57%, and the concrete has a compressive strength of approximately 60 MPa or 90 MPa. The beams are tested in threepoint bending in a servo controlled materials testing system specially designed for the wide range of geometries The casting of the beams is finished. The...

  10. Airplane impacts on reinforced concrete shells

    International Nuclear Information System (INIS)

    Results of nonlinear and ultimate load finite element analyses of reinforced concrete shells subject to airplane impact loads are presented. Algorithmic difficulties and impact-release conditions are discussed. (orig.)

  11. REINFORCED CONCRETE SILO DEMOLITION BY BLASTING

    OpenAIRE

    Josip Krsnik; Zvonimir Ester; Marin Petrov

    1993-01-01

    This paper represents the demolition of reinforced concrete silo by blasting. The loadbearing structure was blasted so that the weight of the silo itself done most of the felling (the paper is published in Croatian).

  12. Continuous Natural Fiber Reinforced Thermoplastic Composites by Fiber Surface Modification

    OpenAIRE

    Patcharat Wongsriraksa; Kohsuke Togashi; Asami Nakai; Hiroyuki Hamada

    2013-01-01

    Continuous natural fiber reinforced thermoplastic materials are expected to replace inorganic fiber reinforced thermosetting materials. However, in the process of fabricating the composite, it is difficult to impregnate the thermoplastic resin into reinforcement fiber because of the high melt viscosity. Therefore, intermediate material, which allows high impregnation during molding, has been investigated for fabricating continuous fiber reinforced thermoplastic composite by aligning resin fib...

  13. Examining the Effects of Reinforcement Context on Relapse of Observing

    OpenAIRE

    Thrailkill, Eric A

    2011-01-01

    Attentional biases occur with various psychological disorders, including drugaddiction and anxiety. Conditioned reinforcement likely plays a role in maintainingattentional biases to stimuli associated with reinforcement for unwanted behavior. Theobserving-response procedure is considered a model of attending as reflected byresponding maintained by conditioned reinforcement. Effects of primary reinforcement on the persistence of observing have been studied in the framework of behavioral moment...

  14. On the Relation between Reinforcer Efficacy and Preference

    Science.gov (United States)

    Lee, May S. H.; Yu, C. T.; Martin, Toby L.; Martin, Garry L.

    2010-01-01

    Most research on stimulus preference and reinforcer assessment involves a preference assessment that is followed by a reinforcer assessment. Typically, the most and least preferred stimuli are tested as reinforcers. In the current study, we first quantified the reinforcing efficacies of six food items and then assessed relative preference for each…

  15. Treatment of multiply controlled destructive behavior with food reinforcement.

    OpenAIRE

    Adelinis, J D; Piazza, C C; Goh, H L

    2001-01-01

    We evaluated the extent to which the positive reinforcement of communication would reduce multiply controlled destructive behavior in the absence of relevant extinction components. When edible reinforcement for appropriate communication and nonfood reinforcers for problem behavior were available simultaneously, responding was allocated almost exclusively toward the behavior that produced edible reinforcement.

  16. Some Effects of Magnitude of Reinforcement on Persistence of Responding

    Science.gov (United States)

    McComas, Jennifer J.; Hartman, Ellie C.; Jimenez, Angel

    2008-01-01

    The influence of magnitude of reinforcement was examined on both response rate and behavioral persistence. During Phase 1, a multiple schedule of concurrent reinforcement was implemented in which reinforcement for one response option was held constant at VI 30 s across both components, while magnitude of reinforcement for the other response option…

  17. Compressive Strength of Fibre Reinforced Concrete

    OpenAIRE

    Jelušič, Matjaž

    2009-01-01

    The thesis features an analysis of the time development of compressive strength of fibre reinforced normal and high strength concrete. Concrete mixtures, taken from the doctoral dissertation of assistant Dr Drago Saje, were used as comparable mixtures to fibre reinforced concrete mixtures with different volume shares of fibres. Two types of steel fibres were used, both featuring the same characteristics but having different lengths (16 and 30 mm), as well as polypropylene fibres. The percenta...

  18. Design Methods for Fibre Reinforced Concrete

    DEFF Research Database (Denmark)

    Stang, Henrik

    The present paper describes the outline of a research project on Fibre Reinforced Concrete (FRC) currently being carried out in Denmark under the supervision of Danish Council of Technology, Danish Technical Research Council and Danish Natural Science Research Counsil.......The present paper describes the outline of a research project on Fibre Reinforced Concrete (FRC) currently being carried out in Denmark under the supervision of Danish Council of Technology, Danish Technical Research Council and Danish Natural Science Research Counsil....

  19. Bond between concrete and reinforcing steel

    OpenAIRE

    Dežman, Andraž

    2015-01-01

    This thesis researches bond characteristics between the 12mm steel reinforcing bar and various types of concrete. Standard Eurocode 2 and FIB Model Code 2010 define ultimate bond stress, which acts like shear stress around the reinforcing bar. In correlation with bond, high strength concrete is poorly represented, furthermore, research and information on fibre concrete are lacking. Therefore, a series of pull-out tests, based on standard SIST EN 10080:2005, have been conducted....

  20. Modular neural networks and reinforcement learning

    OpenAIRE

    Raicevic, Peter

    2004-01-01

    We investigate the effect of modular architecture in an artificial neural network for a reinforcement learning problem. Using the supervised backpropagation algorithm to solve a two-task problem, the network performance can be increased by using networks with modular structures. However, using a modular architecture to solve a two-task reinforcement learning problem will not increase the performance compared to a non-modular structure. We show that by combining a modular structure with a modu...

  1. Forming of UD fibre reinforced thermoplastics

    OpenAIRE

    Haanappel, S.P.

    2013-01-01

    Composite materials are a serious competitor for lightweight metals used in the aerospace and automotive industry. Uni-directional (UD) carbon fibre reinforced thermoplastics are favoured due to their high specific strength and stiffness, but also their good toughness, impact and chemical resistance properties. By heating UD reinforced thermoplastic laminates sufficiently above the melting point of the polymer, these can be stamp-formed to relatively complex geometries. The product is release...

  2. Timeout postponement without increased reinforcement frequency.

    OpenAIRE

    Pietras, C J; Hackenberg, T D

    2000-01-01

    Three experiments were conducted to examine pigeons' postponement of signaled extinction periods (timeouts) from a schedule of food reinforcement when such responding neither decreased overall timeout frequency nor increased the overall frequency of food reinforcement. A discrete-trial procedure was used in which a response during the first 5 s of a trial postponed an otherwise immediate 60-s timeout to a later part of that same trial but had no effect on whether the timeout occurred. During ...

  3. Seismic Stability of Reinforced Soil Slopes

    DEFF Research Database (Denmark)

    Tzavara, I.; Zania, Varvara; Tsompanakis, Y.;

    2012-01-01

    Over recent decades increased research interest has been observed on the dynamic response and stability issues of earth walls and reinforced soil structures. The current study aims to provide an insight into the dynamic response of reinforced soil structures and the potential of the geosynthetics...... impact of the most significant parameters involved, such as the flexibility of the sliding system, the mechanical properties of the soil and of the geosynthetics material, the frequency content of the excitation and the interface shear strength....

  4. Partial reinforcement, extinction, and placebo analgesia

    OpenAIRE

    Yeung, Siu Tsin Au; Colagiuri, Ben; Lovibond, Peter F.; Colloca, Luana

    2014-01-01

    Numerous studies indicate that placebo analgesia can be established via conditioning procedures. However, these studies have exclusively involved conditioning under continuous reinforcement. Thus, it is currently unknown whether placebo analgesia can be established under partial reinforcement and how durable any such effect would be. We tested this possibility using electro-cutaneous pain in healthy volunteers. Sixty undergraduates received placebo treatment (activation of a sham electrode) u...

  5. Efficient strengthening technique for reinforced concrete slabs

    OpenAIRE

    Bonaldo, Everaldo; Barros, Joaquim A. O.; Lourenço, Paulo B.

    2006-01-01

    A promising strengthening strategy, using carbon fiber reinforced polymer (CFRP) materials, consists in applying CFRP laminate strips into pre-cut slits opened in the concrete cover of the elements to strengthen. This strengthening technique is designated by Near Surface Mounted (NSM) and has been successfully used to increase the flexural and the shear resistance of concrete and masonry structures. The present work describes an efficient strategy, using steel fiber reinforced concrete (SFRC)...

  6. Dueling Network Architectures for Deep Reinforcement Learning

    OpenAIRE

    Wang, Ziyu; Schaul, Tom; Hessel, Matteo; van Hasselt, Hado; Lanctot, Marc; De Freitas, Nando

    2015-01-01

    In recent years there have been many successes of using deep representations in reinforcement learning. Still, many of these applications use conventional architectures, such as convolutional networks, LSTMs, or auto-encoders. In this paper, we present a new neural network architecture for model-free reinforcement learning. Our dueling network represents two separate estimators: one for the state value function and one for the state-dependent action advantage function. The main benefit of thi...

  7. Reinforced concrete wall under hydrogen detonation

    International Nuclear Information System (INIS)

    The structural integrity of a reinforced concrete wall in the BWR reactor building under hydrogen detonation conditions has been analysed. Of particular interest is whether the containment integrity can be jeopardised by an external hydrogen detonation. The load carrying capacity of a reinforced concrete wall was studied. The detonation pressure loads were estimated with computerised hand calculations assuming a direct initiation of detonation and applying the strong explosion theory. The results can be considered as rough and conservative estimates for the first shock pressure impact induced by a reflecting detonation wave. Structural integrity may be endangered due to slow pressurisation or dynamic impulse loads associated with local detonations. The static pressure following the passage of a shock front may be relatively high, thus this static or slowly decreasing pressure after a detonation may damage the structure severely. The mitigating effects of the opening of a door on pressure history and structural response were also studied. The non-linear behaviour of the wall was studied under detonations corresponding a detonable hydrogen mass of 0.5 kg and 1.428 kg. Non-linear finite element analyses of the reinforced concrete structure were carried out by the ABAQUS/Explicit program. The reinforcement and its non-linear material behaviour and the tensile cracking of concrete were modelled. Reinforcement was defined as layers of uniformly spaced reinforcing bars in shell elements. In these studies the surrounding structures of the non-linearly modelled reinforced concrete wall were modelled using idealised boundary conditions. Especially concrete cracking and yielding of the reinforcement was monitored during the numerical simulation. (au)

  8. Seismic analysis of infilled reinforced concrete frames

    OpenAIRE

    Novak, Luka

    2013-01-01

    The effect of masonry infills on seismic behaviour of reinforced concrete frames is described. In the first part of the thesis, the theoretical background and procedure for seismic analysis of such structures according to Eurocode 8 are presented. The effect of masonry infill was demonstrated by means of an example of four-storey reinforced-concrete building, including the consideration of the effect of soft storey mechanism. All linear elastic analyses were performed with ETABS software. The...

  9. Asynchronous Methods for Deep Reinforcement Learning

    OpenAIRE

    Mnih, Volodymyr; Badia, Adrià Puigdomènech; Mirza, Mehdi; Graves, Alex; Lillicrap, Timothy P.; Harley, Tim; Silver, David; Kavukcuoglu, Koray

    2016-01-01

    We propose a conceptually simple and lightweight framework for deep reinforcement learning that uses asynchronous gradient descent for optimization of deep neural network controllers. We present asynchronous variants of four standard reinforcement learning algorithms and show that parallel actor-learners have a stabilizing effect on training allowing all four methods to successfully train neural network controllers. The best performing method, an asynchronous variant of actor-critic, surpasse...

  10. Deep Reinforcement Learning With Macro-Actions

    OpenAIRE

    Durugkar, Ishan P.; Rosenbaum, Clemens; Dernbach, Stefan; Mahadevan, Sridhar

    2016-01-01

    Deep reinforcement learning has been shown to be a powerful framework for learning policies from complex high-dimensional sensory inputs to actions in complex tasks, such as the Atari domain. In this paper, we explore output representation modeling in the form of temporal abstraction to improve convergence and reliability of deep reinforcement learning approaches. We concentrate on macro-actions, and evaluate these on different Atari 2600 games, where we show that they yield significant impro...

  11. Concrete reinforced by braided fibre composite rods

    OpenAIRE

    Fangueiro, Raúl; Sousa, Guilherme José Miranda de; Soutinho, Hélder Filipe Cunha; Jalali, Said; Araújo, Mário Duarte de

    2005-01-01

    One of the most serious problems affecting concrete is corrosion of the steel reinforcement. Corrosion may occur due to reaction of lime present in hydrated cement with carbon dioxide or to the action of chlorides. The braiding technique is probably the most ancient production process for textile structures. Normally used for ropes and cables, braided fabrics are also very interesting for composite reinforcements due to their characteristics: in-plane multiaxial ...

  12. Vicarious Reinforcement in Rhesus Macaques (Macaca Mulatta)

    OpenAIRE

    Chang, Steve W. C.; Amy A. Winecoff; Platt, Michael L.

    2011-01-01

    What happens to others profoundly influences our own behavior. Such other-regarding outcomes can drive observational learning, as well as motivate cooperation, charity, empathy, and even spite. Vicarious reinforcement may serve as one of the critical mechanisms mediating the influence of other-regarding outcomes on behavior and decision-making in groups. Here we show that rhesus macaques spontaneously derive vicarious reinforcement from observing rewards given to another monkey, and that this...

  13. Vicarious Reinforcement In Rhesus Macaques (Macaca mulatta)

    OpenAIRE

    Chang, Steve W. C.; Amy A. Winecoff; Platt, Michael L.

    2011-01-01

    What happens to others profoundly influences our own behavior. Such other-regarding outcomes can drive observational learning, as well as motivate cooperation, charity, empathy, and even spite. Vicarious reinforcement may serve as one of the critical mechanisms mediating the influence of other-regarding outcomes on behavior and decision-making in groups. Here we show that rhesus macaques spontaneously derive vicarious reinforcement from observing rewards given to another monkey, and that t...

  14. Collaborative reinforcement learning of autonomic behaviour

    OpenAIRE

    Dowling, Jim; CUNNINGHAM, RAYMOND; Curran, Eoin; Cahill, Vinny

    2004-01-01

    peer-reviewed This paper introduces Collaborative Reinforcement Learning (CRL), a coordination model for solving system-wide optimisation problems in distributed systems where there is no support for global state. In CRL the autonomic properties of a distributed system emerge from the coordination of individual agents solving discrete optimisation problems using Reinforcement Learning. In the context of an ad hoc routing protocol, we show how system-wide optimisation in CRL can be used t...

  15. Reinforcement learning: Computational theory and biological mechanisms

    OpenAIRE

    Doya, Kenji

    2007-01-01

    Reinforcement learning is a computational framework for an active agent to learn behaviors on the basis of a scalar reward signal. The agent can be an animal, a human, or an artificial system such as a robot or a computer program. The reward can be food, water, money, or whatever measure of the performance of the agent. The theory of reinforcement learning, which was developed in an artificial intelligence community with intuitions from animal learning theory, is now givi...

  16. Reinforcement Learning Using Local Adaptive Models

    OpenAIRE

    Borga, Magnus

    1995-01-01

    In this thesis, the theory of reinforcement learning is described and its relation to learning in biological systems is discussed. Some basic issues in reinforcement learning, the credit assignment problem and perceptual aliasing, are considered. The methods of temporal difference are described. Three important design issues are discussed: information representation and system architecture, rules for improving the behaviour and rules for the reward mechanisms. The use of local adaptive models...

  17. Food Reinforcement and Eating: A Multilevel Analysis

    OpenAIRE

    Epstein, Leonard H.; Leddy, John J; Temple, Jennifer L; Faith, Myles S.

    2007-01-01

    Eating represents a choice among many alternative behaviors. The purpose of this review is to provide an overview of how food reinforcement and behavioral choice theory are related to eating and to show how this theoretical approach may help organize research on eating from molecular genetics through treatment and prevention of obesity. Special emphasis is placed on how food reinforcement and behavioral choice theory are relevant to understanding excess energy intake and obesity and how they ...

  18. Getting a Whiff of Speciation by Reinforcement

    OpenAIRE

    Ortiz-Barrientos Daniel; Counterman Brian A

    2004-01-01

    Reinforcement occurs when natural selection strengthens behavioral discrimination to prevent costly interspecies matings, such as when matings produce sterile hybrids. This evolutionary process can complete speciation, thereby providing a direct link between Darwin's theory of natural selection and the origin of new species. Here, by examining a case of speciation by reinforcement in Drosophila, we present the first high-resolution genetic study of variation within species for female mating d...

  19. Process for preparing polymer reinforced silica aerogels

    Science.gov (United States)

    Meador, Mary Ann B. (Inventor); Capadona, Lynn A. (Inventor)

    2011-01-01

    Process for preparing polymer-reinforced silica aerogels which comprises a one-pot reaction of at least one alkoxy silane in the presence of effective amounts of a polymer precursor to obtain a silica reaction product, the reaction product is gelled and subsequently subjected to conditions that promotes polymerization of the precursor and then supercritically dried to obtain the polymer-reinforced monolithic silica aerogels.

  20. The reinforcement axiom under sequential positional rules

    OpenAIRE

    Courtin, Sebastien; Mbih, Boniface; Moyouwou, Issofa; Senné, Thomas

    2010-01-01

    The reinforcement axiom roughly states that when an alternative is selected by two different constituencies, it must also be selected by their union. Hare and Coombs rules are special cases of sequential positional voting rules, which are known to violate this axiom. In this article, we first show that reinforcement can be violated by all such rules. We then evaluate, by the use of Monte Carlo simulations and the Fishburn-Gehrlein technique, the proportion of profiles at which this phenomenon...

  1. DESIGN AND CALCULATION OF THE CONNECTION REINFORCING BARS CRIMPING SLEEVES

    Directory of Open Access Journals (Sweden)

    Y. Y. Luchko

    2007-10-01

    Full Text Available The problem of connection of high-strength carbon and thermomechanically strengthened reinforcements is considered in the paper. The analysis of results of previous investigations from world practice is conducted. The construction of connection is offered and the research of the beam reinforced concrete elements reinforced by the combined reinforcement on durability, crack-durability and deformations is conducted. This research showed the expedience of such a connection and reliable working capacity of the reinforced concrete constructions reinforced by the combined reinforcement.

  2. Nondestructive testing of lining of reinforced concrete bridges

    International Nuclear Information System (INIS)

    The distribution, course and profile of concrete reinforcement bars are found using a magnetic indicator or radiographically mostly using a 60Co radioactive source with an activity of 370 GBq to 1.11 TBq. With simple girder bridges the lower tension reinforcement is controlled in the centre of the span, slide reinforcement near the support, reinforcement in the slab and possibly reinforcement in the foundation sill, with continuous girder bridges the upper tension reinforcement is determined using stereoscopic photographing from two foci. For wider girders the sources are placed in holes drilled in the girders at a distance of 200 mm. The magnetic indicator of reinforcement is used for controlling slab bridges of less reinforced concrete while the radiographic method is used for monitoring bridges with thicker reinforcement. The distribution of reinforcement in cross section is monitored graphically by plotting the configuration at which the cross section was scanned. (E.S.)

  3. Examining the Generality of Children's Preference for Contingent Reinforcement via Extension to Different Responses, Reinforcers, and Schedules

    Science.gov (United States)

    Luczynski, Kevin C.; Hanley, Gregory P.

    2010-01-01

    Studies that have assessed whether children prefer contingent reinforcement (CR) or noncontingent reinforcement (NCR) have shown that they prefer CR. Preference for CR has, however, been evaluated only under continuous reinforcement (CRF) schedules. The prevalence of intermittent reinforcement (INT) warrants an evaluation of whether preference for…

  4. Zero-reinforcement vessel closures

    International Nuclear Information System (INIS)

    Access to the secondary side of a nuclear steam generator is required in order to properly inspect and maintain critical components throughout the life. For the most part, it is only on newer units that sufficient openings have been provided. Older units must be field modified to provide access to the tube bundle and internal lateral support components for inspection and penetration by cleaning equipment. In order to avoid post weld heat treatment after welding on some materials it would be desirable to machine the opening directly into the pressure boundary without providing weld build-up to compensate for the material removed. In such a case, the pressure boundary may be locally thinned below the minimum thickness required by the ASME code. As a result it is not possible to meet reinforcement limits or elastic primary stress limited of the code. However, the ASME code permits justification of the design by utilizing elastic-plastic methods. Elastic-plastic analysis can be utilized to demonstrate shake-down to elastic action and to demonstrate that small deformations in the region of the gasket seating surfaces, or any loss of bolt preload, have not compromised leak tightness. Employing the technique developed by the authors for application in ANSYS, it is feasible to carry-out such a design analysis including the effects of time varying thermal stress. This paper presents the highlights of such an analysis. It is important to note that the method also permits the analysis of openings in locations formerly considered too restrictive, such as near support and major structural discontinuities. (author)

  5. Material optimization of fiber reinforced composites applying a damage formulation

    OpenAIRE

    Kato, Junji

    2010-01-01

    The present thesis proposes material optimization schemes for fiber reinforced composites, specifically for a new composite material, denoted as Fiber Reinforced Concrete (FRC) or Textile Reinforced Concrete (TRC); here a reinforcement mesh of long carbon or glass fibers is embedded in a fine grained concrete (mortar) matrix. Unlike conventional steel reinforcement, these textile fibers are corrosion free; this holds also for AR-glass due to its high alkali-proof. This favorable property allo...

  6. ON THE RELATION BETWEEN REINFORCER EFFICACY AND PREFERENCE

    OpenAIRE

    Lee, May S. H.; Yu, C.T; Martin, Toby L.; Martin, Garry L.

    2010-01-01

    Most research on stimulus preference and reinforcer assessment involves a preference assessment that is followed by a reinforcer assessment. Typically, the most and least preferred stimuli are tested as reinforcers. In the current study, we first quantified the reinforcing efficacies of six food items and then assessed relative preference for each item. Relative preference ranking and reinforcer efficacies showed almost perfect concordance for 1 participant and partial concordance for the oth...

  7. Negative reinforcement in applied behavior analysis: an emerging technology.

    OpenAIRE

    Iwata, B A

    1987-01-01

    Although the effects of negative reinforcement on human behavior have been studied for a number of years, a comprehensive body of applied research does not exist at this time. This article describes three aspects of negative reinforcement as it relates to applied behavior analysis: behavior acquired or maintained through negative reinforcement, the treatment of negatively reinforced behavior, and negative reinforcement as therapy. A consideration of research currently being done in these area...

  8. EXAMINING THE GENERALITY OF CHILDREN'S PREFERENCE FOR CONTINGENT REINFORCEMENT VIA EXTENSION TO DIFFERENT RESPONSES, REINFORCERS, AND SCHEDULES

    OpenAIRE

    Luczynski, Kevin C; Hanley, Gregory P

    2010-01-01

    Studies that have assessed whether children prefer contingent reinforcement (CR) or noncontingent reinforcement (NCR) have shown that they prefer CR. Preference for CR has, however, been evaluated only under continuous reinforcement (CRF) schedules. The prevalence of intermittent reinforcement (INT) warrants an evaluation of whether preference for CR persists as the schedule of reinforcement is thinned. In the current study, we evaluated 2 children's preference for contingent versus noncontin...

  9. Shear behaviour of reinforced phyllite concrete beams

    International Nuclear Information System (INIS)

    Highlights: ► Phyllite concrete beams often exhibited shear with anchorage bond failure. ► Different shear design provisions for reinforced phyllite beams are compared. ► Predicted shear capacity of phyllite beams must be modified by a reduction factor. -- Abstract: The shear behaviour of concrete beams made from phyllite aggregates subjected to monotonic and cyclic loading is reported. First diagonal shear crack load of beams with and without shear reinforcement was between 42–58% and 42–92% of the failure loads respectively. The phyllite concrete beams without shear links had lower post-diagonal cracking shear resistance compared to corresponding phyllite beams with shear links. As a result of hysteretic energy dissipation, limited cyclic loading affected the stiffness, strength and deformation of the phyllite beams with shear reinforcement. Generally, beams with and without shear reinforcement showed anchorage bond failure in addition to the shear failure due to high stress concentration near the supports. The ACI, BS and EC codes are conservative for the prediction of phyllite concrete beams without shear reinforcement but they all overestimate the shear strength of phyllite concrete beams with shear reinforcement. It is recommended that the predicted shear capacity of phyllite beams reinforced with steel stirrups be modified by a reduction factor of 0.7 in order to specify a high enough safety factor on their ultimate strength. It is also recommended that susceptibility of phyllite concrete beams to undergo anchorage bond failure is averted in design by the provision of greater anchorage lengths than usually permitted.

  10. Vicarious reinforcement in rhesus macaques (macaca mulatta).

    Science.gov (United States)

    Chang, Steve W C; Winecoff, Amy A; Platt, Michael L

    2011-01-01

    What happens to others profoundly influences our own behavior. Such other-regarding outcomes can drive observational learning, as well as motivate cooperation, charity, empathy, and even spite. Vicarious reinforcement may serve as one of the critical mechanisms mediating the influence of other-regarding outcomes on behavior and decision-making in groups. Here we show that rhesus macaques spontaneously derive vicarious reinforcement from observing rewards given to another monkey, and that this reinforcement can motivate them to subsequently deliver or withhold rewards from the other animal. We exploited Pavlovian and instrumental conditioning to associate rewards to self (M1) and/or rewards to another monkey (M2) with visual cues. M1s made more errors in the instrumental trials when cues predicted reward to M2 compared to when cues predicted reward to M1, but made even more errors when cues predicted reward to no one. In subsequent preference tests between pairs of conditioned cues, M1s preferred cues paired with reward to M2 over cues paired with reward to no one. By contrast, M1s preferred cues paired with reward to self over cues paired with reward to both monkeys simultaneously. Rates of attention to M2 strongly predicted the strength and valence of vicarious reinforcement. These patterns of behavior, which were absent in non-social control trials, are consistent with vicarious reinforcement based upon sensitivity to observed, or counterfactual, outcomes with respect to another individual. Vicarious reward may play a critical role in shaping cooperation and competition, as well as motivating observational learning and group coordination in rhesus macaques, much as it does in humans. We propose that vicarious reinforcement signals mediate these behaviors via homologous neural circuits involved in reinforcement learning and decision-making. PMID:21516263

  11. Vicarious Reinforcement In Rhesus Macaques (Macaca mulatta

    Directory of Open Access Journals (Sweden)

    Steve W. C. Chang

    2011-03-01

    Full Text Available What happens to others profoundly influences our own behavior. Such other-regarding outcomes can drive observational learning, as well as motivate cooperation, charity, empathy, and even spite. Vicarious reinforcement may serve as one of the critical mechanisms mediating the influence of other-regarding outcomes on behavior and decision-making in groups. Here we show that rhesus macaques spontaneously derive vicarious reinforcement from observing rewards given to another monkey, and that this reinforcement can motivate them to subsequently deliver or withhold rewards from the other animal. We exploited Pavlovian and instrumental conditioning to associate rewards to self (M1 and/or rewards to another monkey (M2 with visual cues. M1s made more errors in the instrumental trials when cues predicted reward to M2 compared to when cues predicted reward to M1, but made even more errors when cues predicted reward to no one. In subsequent preference tests between pairs of conditioned cues, M1s preferred cues paired with reward to M2 over cues paired with reward to no one. By contrast, M1s preferred cues paired with reward to self over cues paired with reward to both monkeys simultaneously. Rates of attention to M2 strongly predicted the strength and valence of vicarious reinforcement. These patterns of behavior, which were absent in nonsocial control trials, are consistent with vicarious reinforcement based upon sensitivity to observed, or counterfactual, outcomes with respect to another individual. Vicarious reward may play a critical role in shaping cooperation and competition, as well as motivating observational learning and group coordination in rhesus macaques, much as it does in humans. We propose that vicarious reinforcement signals mediate these behaviors via homologous neural circuits involved in reinforcement learning and decision-making.

  12. Reinforcement Efficiency Analysis of Geosynthetic-Reinforced Embankment with Different Soil Pronerties

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on finite element (FE) method, an analysis program of geosynthetic-reinforcement embankments (GRE) is proposed. The improvement of stress field of surface layer of GRE after reinforcement can be indicated by this program. The comparison of failure area ratio of foundation soil before and after reinforcement is made, so that the efficiency of geosynthetic reinforcement under different soft soil properties can be shown. The embankment soil is simulated with Duncan-Chang model in this program, while reinforcement is modeled with linear elastic model and interface of reinforcement-soil by Goodman elements. Parameters about foundation soil, such as cohesion, inner friction angle and unit weight are considered, as well as three Duncan-Chang model parameters: modulus coefficient, bulk modulus coefficient and break ratio. The relationship between those soil parameters and failure area ratio indicate the reinforcement efficiency of GRE. The results show the cohesion and inner friction angle are the most important parameters for reducing the failure area,while modulus coefficient and bulk modulus coefficient, have little effect on the calculation results; the reinforcement efficiency is low if the cohesion and inner friction angle of foundation soil are too small or too big; different foundation soil will get different conclusions. The selection of model parameter is an important procedure for accurate modeling of GRE by numerical method.

  13. Exploring the Effectiveness of Reinforcement in Covert Reinforcement Therapy: A Case Study.

    Science.gov (United States)

    Bernal, Guillermo; Wisocki, Patricia A.

    The relative effects of imagerial covert rehearsal with attentional shifts and the use of an independent reinforcing agent in a covert reinforcement therapy were compared. A 17-year-old female student, requesting treatment for a snake phobia, served as the subject. The phobia was measured along four dimensions: behavioral approaches to a live…

  14. Providing Alternative Reinforcers to Facilitate Tolerance to Delayed Reinforcement Following Functional Communication Training

    Science.gov (United States)

    Austin, Jillian E.; Tiger, Jeffrey H.

    2015-01-01

    The earliest stages of functional communication training (FCT) involve providing immediate and continuous reinforcement for a communicative response (FCR) that is functionally equivalent to the targeted problem behavior. However, maintaining immediate reinforcement is not practical, and the introduction of delays is associated with increased…

  15. Model-Based Reinforcement Learning under Concurrent Schedules of Reinforcement in Rodents

    Science.gov (United States)

    Huh, Namjung; Jo, Suhyun; Kim, Hoseok; Sul, Jung Hoon; Jung, Min Whan

    2009-01-01

    Reinforcement learning theories postulate that actions are chosen to maximize a long-term sum of positive outcomes based on value functions, which are subjective estimates of future rewards. In simple reinforcement learning algorithms, value functions are updated only by trial-and-error, whereas they are updated according to the decision-maker's…

  16. A Comparison of Noncontingent plus Contingent Reinforcement to Contingent Reinforcement Alone on Students' Academic Performance

    Science.gov (United States)

    Panahon, Carlos J.; Martens, Brian K.

    2013-01-01

    Noncontingent reinforcement (NCR) can be described as time-based or response-independent delivery of stimuli with known reinforcing properties. Previous research has shown NCR to reduce problem behavior in individuals with developmental disabilities and to interfere with the acquisition of more desired alternative behavior. To date, however,…

  17. Evaluation of size dependent design shear strength of reinforced concrete beams without web reinforcement

    Indian Academy of Sciences (India)

    G Appa Rao; S S Injaganeri

    2011-06-01

    Analytical studies on the effect of depth of beam and several parameters on the shear strength of reinforced concrete beams are reported. A large data base available has been segregated and a nonlinear regression analysis (NLRA) has been performed for developing the refined design models for both, the cracking and the ultimate shear strengths of reinforced concrete (RC) beams without web reinforcement. The shear strength of RC beams is size dependent, which needs to be evaluated and incorporated in the appropriate size effect models. The proposed models are functions of compressive strength of concrete, percentage of flexural reinforcement and depth of beam. The structural brittleness of large size beams seems to be severe compared with highly ductile small size beams at a given quantity of flexural reinforcement. The proposed models have been validated with the existing popular models as well as with the design code provisions.

  18. Investigating aluminum alloy reinforced by graphene nanoflakes

    Energy Technology Data Exchange (ETDEWEB)

    Yan, S.J., E-mail: shaojiuyan@126.com [Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Dai, S.L.; Zhang, X.Y.; Yang, C.; Hong, Q.H.; Chen, J.Z. [Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Lin, Z.M. [Aviation Industry Corporation of China, Beijing 100022 (China)

    2014-08-26

    As one of the most important engineering materials, aluminum alloys have been widely applied in many fields. However, the requirement of enhancing their mechanical properties without sacrificing the ductility is always a challenge in the development of aluminum alloys. Thanks to the excellent physical and mechanical properties, graphene nanoflakes (GNFs) have been applied as promising reinforcing elements in various engineering materials, including polymers and ceramics. However, the investigation of GNFs as reinforcement phase in metals or alloys, especially in aluminum alloys, is still very limited. In this study, the aluminum alloy reinforced by GNFs was successfully prepared via powder metallurgy approach. The GNFs were mixed with aluminum alloy powders through ball milling and followed by hot isostatic pressing. The green body was then hot extruded to obtain the final GNFs reinforced aluminum alloy nanocomposite. The scanning electron microscopy and transmission electron microscope analysis show that GNFs were well dispersed in the aluminum alloy matrix and no chemical reactions were observed at the interfaces between the GNFs and aluminum alloy matrix. The mechanical properties' testing results show that with increasing filling content of GNFs, both tensile and yield strengths were remarkably increased without losing the ductility performance. These results not only provided a pathway to achieve the goal of preparing high strength aluminum alloys with excellent ductilitybut they also shed light on the development of other metal alloys reinforced by GNFs.

  19. Global reinforcement training of CrossNets

    Science.gov (United States)

    Ma, Xiaolong

    2007-10-01

    Hybrid "CMOL" integrated circuits, incorporating advanced CMOS devices for neural cell bodies, nanowires as axons and dendrites, and latching switches as synapses, may be used for the hardware implementation of extremely dense (107 cells and 1012 synapses per cm2) neuromorphic networks, operating up to 10 6 times faster than their biological prototypes. We are exploring several "Cross- Net" architectures that accommodate the limitations imposed by CMOL hardware and should allow effective training of the networks without a direct external access to individual synapses. Our studies have show that CrossNets based on simple (two-terminal) crosspoint devices can work well in at least two modes: as Hop-field networks for associative memory and multilayer perceptrons for classification tasks. For more intelligent tasks (such as robot motion control or complex games), which do not have "examples" for supervised learning, more advanced training methods such as the global reinforcement learning are necessary. For application of global reinforcement training algorithms to CrossNets, we have extended Williams's REINFORCE learning principle to a more general framework and derived several learning rules that are more suitable for CrossNet hardware implementation. The results of numerical experiments have shown that these new learning rules can work well for both classification tasks and reinforcement tasks such as the cartpole balancing control problem. Some limitations imposed by the CMOL hardware need to be carefully addressed for the the successful application of in situ reinforcement training to CrossNets.

  20. Investigating aluminum alloy reinforced by graphene nanoflakes

    International Nuclear Information System (INIS)

    As one of the most important engineering materials, aluminum alloys have been widely applied in many fields. However, the requirement of enhancing their mechanical properties without sacrificing the ductility is always a challenge in the development of aluminum alloys. Thanks to the excellent physical and mechanical properties, graphene nanoflakes (GNFs) have been applied as promising reinforcing elements in various engineering materials, including polymers and ceramics. However, the investigation of GNFs as reinforcement phase in metals or alloys, especially in aluminum alloys, is still very limited. In this study, the aluminum alloy reinforced by GNFs was successfully prepared via powder metallurgy approach. The GNFs were mixed with aluminum alloy powders through ball milling and followed by hot isostatic pressing. The green body was then hot extruded to obtain the final GNFs reinforced aluminum alloy nanocomposite. The scanning electron microscopy and transmission electron microscope analysis show that GNFs were well dispersed in the aluminum alloy matrix and no chemical reactions were observed at the interfaces between the GNFs and aluminum alloy matrix. The mechanical properties' testing results show that with increasing filling content of GNFs, both tensile and yield strengths were remarkably increased without losing the ductility performance. These results not only provided a pathway to achieve the goal of preparing high strength aluminum alloys with excellent ductilitybut they also shed light on the development of other metal alloys reinforced by GNFs

  1. Reinforcement of Conducting Silver-based Materials

    Directory of Open Access Journals (Sweden)

    Heike JUNG

    2014-09-01

    Full Text Available Silver is a well-known material in the field of contact materials because of its high electrical and thermal conductivity. However, due to its bad mechanical and switching properties, silver alloys or reinforcements of the ductile silver matrix are required. Different reinforcements, e. g. tungsten, tungsten carbide, nickel, cadmium oxide or tin oxide, are used in different sectors of switches. To reach an optimal distribution of these reinforcements, various manufacturing techniques (e. g. powder blending, preform infiltration, wet-chemical methods, internal oxidation are being used for the production of these contact materials. Each of these manufacturing routes offers different advantages and disadvantages. The mechanical alloying process displays a successful and efficient method to produce particle-reinforced metal-matrix composite powders. This contribution presents the obtained fine disperse microstructure of tungsten-particle-reinforced silver composite powders produced by the mechanical alloying process and displays this technique as possible route to provide feedstock powders for subsequent consolidation processes. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4889

  2. Origins of altered reinforcement effects in ADHD

    Directory of Open Access Journals (Sweden)

    Tripp Gail

    2009-02-01

    Full Text Available Abstract Attention-deficit/hyperactivity disorder (ADHD, characterized by hyperactivity, impulsiveness and deficient sustained attention, is one of the most common and persistent behavioral disorders of childhood. ADHD is associated with catecholamine dysfunction. The catecholamines are important for response selection and memory formation, and dopamine in particular is important for reinforcement of successful behavior. The convergence of dopaminergic mesolimbic and glutamatergic corticostriatal synapses upon individual neostriatal neurons provides a favorable substrate for a three-factor synaptic modification rule underlying acquisition of associations between stimuli in a particular context, responses, and reinforcers. The change in associative strength as a function of delay between key stimuli or responses, and reinforcement, is known as the delay of reinforcement gradient. The gradient is altered by vicissitudes of attention, intrusions of irrelevant events, lapses of memory, and fluctuations in dopamine function. Theoretical and experimental analyses of these moderating factors will help to determine just how reinforcement processes are altered in ADHD. Such analyses can only help to improve treatment strategies for ADHD.

  3. Self reinforced polymer-polymer composites

    Directory of Open Access Journals (Sweden)

    M. Bilewicz

    2007-10-01

    Full Text Available Purpose: Purpose of this paper is the applying of new technology in injection moulding technique and investigation of reinforcement of PC as dispersed phase inside PP matrix (Table 1. Second aim of work is enrichment of those composites by nanoclay and analyzing mechanical behaviour of nanocomposites.Design/methodology/approach: According to design of experiments (DOE specimens were injection moulded in the shape of rectangular bars. Additionally advanced technology of melt manipulation inside mold cavity after injection was used. To achieve this purpose Ferromatik Milacron injection moulding machine, equipped with externally controlled mold was used.Findings: Addition of nanoclay clearly presents highly reinforced system, especially for neat matrix. Evenly dispersed PC particles within PP majority show reinforcement as well. Inducement of shear rate in injection moulding radically improved absorption of energy in nanocomposite.Research limitations/implications: Different variation of material composition, such combination with other polymers and use of different reinforcements (flexible or either rigid is required to be checked in the further work.Practical implications: Reinforcement obtained thanks to dispersed phase and nanofillers creates composites with improved mechanical properties.Originality/value: Morphology development reflects on mechanical behaviour. Its manipulation may affect and improve mechanical properties. Use of advanced technologies opens wide range of possibilities in processing of polymer based systems. At present there is limited number of research of processing-structure-properties relationships of polymer-polymer composites and nanocomposites.

  4. Origins of altered reinforcement effects in ADHD.

    Science.gov (United States)

    Johansen, Espen Borgå; Killeen, Peter R; Russell, Vivienne A; Tripp, Gail; Wickens, Jeff R; Tannock, Rosemary; Williams, Jonathan; Sagvolden, Terje

    2009-01-01

    Attention-deficit/hyperactivity disorder (ADHD), characterized by hyperactivity, impulsiveness and deficient sustained attention, is one of the most common and persistent behavioral disorders of childhood. ADHD is associated with catecholamine dysfunction. The catecholamines are important for response selection and memory formation, and dopamine in particular is important for reinforcement of successful behavior. The convergence of dopaminergic mesolimbic and glutamatergic corticostriatal synapses upon individual neostriatal neurons provides a favorable substrate for a three-factor synaptic modification rule underlying acquisition of associations between stimuli in a particular context, responses, and reinforcers. The change in associative strength as a function of delay between key stimuli or responses, and reinforcement, is known as the delay of reinforcement gradient. The gradient is altered by vicissitudes of attention, intrusions of irrelevant events, lapses of memory, and fluctuations in dopamine function. Theoretical and experimental analyses of these moderating factors will help to determine just how reinforcement processes are altered in ADHD. Such analyses can only help to improve treatment strategies for ADHD. PMID:19226460

  5. The Genetics of Speciation by Reinforcement

    Directory of Open Access Journals (Sweden)

    Ortiz-Barrientos Daniel

    2004-01-01

    Full Text Available Reinforcement occurs when natural selection strengthens behavioral discrimination to prevent costly interspecies matings, such as when matings produce sterile hybrids. This evolutionary process can complete speciation, thereby providing a direct link between Darwin's theory of natural selection and the origin of new species. Here, by examining a case of speciation by reinforcement in Drosophila, we present the first high-resolution genetic study of variation within species for female mating discrimination that is enhanced by natural selection. We show that reinforced mating discrimination is inherited as a dominant trait, exhibits variability within species, and may be influenced by a known set of candidate genes involved in olfaction. Our results show that the genetics of reinforced mating discrimination is different from the genetics of mating discrimination between species, suggesting that overall mating discrimination might be a composite phenomenon, which in Drosophila could involve both auditory and olfactory cues. Examining the genetics of reinforcement provides a unique opportunity for both understanding the origin of new species in the face of gene flow and identifying the genetic basis of adaptive female species preferences, two major gaps in our understanding of speciation.

  6. Numerical study on deformation and failure of reinforced sand

    Institute of Scientific and Technical Information of China (English)

    PENG Fang-le; LI Jian-zhong; Tatsuoka Fumio

    2005-01-01

    In order to investigate the deformation and failure of reinforced sand, and the reinforcing mechanism of flexible and rigid reinforcement, a set of plane strain compression tests of dense Toyoura reinforced sand with planar reinforcement of a wide range of stiffness were analysed by a nonlinear finite element method. The analysis was incorporated into an energy-based elasto-plastic constitutive model for sand to develop a stress path-independent work-hardening parameter based on the modified plastic strain energy concept. Numerical results indicate that the global stress-strain relations of sand specimens are reinforced by using relatively flexible and rigid reinforcement, and an unreinforced sand specimen can be reasonably simulated by the current finite element method. It is also found that the reinforcing mechanism and progressive failure with a development of shear bands in reinforced sand can be reasonably examined by the finite element method.

  7. Investigation of rectangular concrete columns reinforced or prestressed with fiber reinforced polymer (FRP) bars or tendons

    Science.gov (United States)

    Choo, Ching Chiaw

    Fiber reinforced polymer (FRP) composites have been increasingly used in concrete construction. This research focused on the behavior of concrete columns reinforced with FRP bars, or prestressed with FRP tendons. The methodology was based the ultimate strength approach where stress and strain compatibility conditions and material constitutive laws were applied. Axial strength-moment (P-M) interaction relations of reinforced or prestressed concrete columns with FRP, a linearly-elastic material, were examined. The analytical results identified the possibility of premature compression and/or brittle-tension failure occurring in FRP reinforced and prestressed concrete columns where sudden and explosive type failures were expected. These failures were related to the rupture of FRP rebars or tendons in compression and/or in tension prior to concrete reaching its ultimate strain and strength. The study also concluded that brittle-tension failure was more likely to occur due to the low ultimate tensile strain of FRP bars or tendons as compared to steel. In addition, the failures were more prevalent when long term effects such as creep and shrinkage of concrete, and creep rupture of FRP were considered. Barring FRP failure, concrete columns reinforced with FRP, in some instances, gained significant moment resistance. As expected the strength interaction of slender steel or FRP reinforced concrete columns were dependent more on column length rather than material differences between steel and FRP. Current ACI minimum reinforcement ratio for steel (rhomin) reinforced concrete columns may not be adequate for use in FRP reinforced concrete columns. Design aids were developed in this study to determine the minimum reinforcement ratio (rhof,min) required for rectangular reinforced concrete columns by averting brittle-tension failure to a failure controlled by concrete crushing which in nature was a less catastrophic and more gradual type failure. The proposed method using rhof

  8. Measurement of reinforcement corrosion in marine structures

    International Nuclear Information System (INIS)

    The marine environment is known to be aggressive. Structures constructed on this belt need to under periodic assessment n order to ensure no defects or signs of n deterioration had occurred. One of the most common deterioration that occurs on marine structures is corrosion of the reinforcement. Corrosion is an electrochemical process. The product of corrosion can increase the reinforcement volume, hence causing cracking on concrete cover. If no action is taken, ill follow and this will affect the delamination and spalling of concrete will follow structures integrity. It is therefore important to know the state of the structures condition by monitoring them periodically. NDT techniques that can detect the occurrence of corrosion of reinforcement in concrete uses half cell and resistivity meter. The method of application and interpretation of results are discussed. (author)

  9. Numerical Limit Analysis of Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Larsen, Kasper Paaske

    For more than half a century, limit state analysis based on the extremum principles have been used to assess the load bearing capacity of reinforced concrete structures. Extensi- ve research within the field has lead to several techniques for performing such analysis manually. While these manual...... limit state analysis problems. The work focuses on determination of the load bearing capacity of reinforced concrete structures by employing the lower bound theorem and a finite element method using equilibrium elements is developed. The recent year’s development within the field of convex optimization...... is applied to solve the limit state problems. Three different element types have been developed and tested. The first is a solid tetra- hedral element with a linear stress distribution. The tri-axial stress state in the element is decomposed into concrete and reinforcement stresses, to which separate...

  10. Anomalous crack propagation in reinforced natural rubber

    Science.gov (United States)

    Sotta, Paul; Gabrielle, Brice; Long, Didier; Vanel, Loic; Albouy, Pierre-Antoine; Peditto, Francesca

    2009-03-01

    In reinforced natural rubber, crack propagation in mode I exhibits rotation of the tear in a direction perpendicular to the usual one. Our objective is, first, to understand the impact of this phenomenon on fracture toughness of the material, and, secondly, to understand how this phenomenon is related to the specific properties of reinforced natural rubber. To this aim, we combine measurements of ultimate properties, measurements of the number and length of tear rotations as a function of loading velocity and temperature, and investigation of material heterogeneities at sub-micrometric scales, originating both from fillers and strain-induced crystallites (strain-induced crystallinity is measured up to failure by X ray diffraction), in natural rubber samples reinforced by nanometric aggregates. Observations suggest that tear rotation is related both to the mechanical anisotropy induced by strain-induced crystallinity and to the dissipative properties of the material at high strain.

  11. Measurement of reinforcement corrosion in marine structures

    International Nuclear Information System (INIS)

    The marine environment is known to be aggressive. Structures constructed on this belt need to undergo periodic assessment in order to ensure no defects or signs of deterioration had occurred. One of the most common deterioration that occurs on marine structures is corrosion of the reinforcement. Corrosion is an electrochemical process. The product of corrosion can increase the reinforcement volume, hence causing cracking on concrete cover. If no action is taken, delamination and spalling of concrete will follow and this will affect the structures integrity. It is therefore important to know the state of the structures condition by monitoring them periodically. NDT techniques that can detect the occurrence of corrosion of reinforcement in concrete uses half cell and resistivity meter. The method of application and interpretation of results are discussed. (author)

  12. Fiber Reinforced Composite Cores and Panels

    Science.gov (United States)

    Day, Stephen W. (Inventor); Campbell, G. Scott (Inventor); Tilton, Danny E. (Inventor); Stoll, Frederick (Inventor); Sheppard, Michael (Inventor); Banerjee, Robin (Inventor)

    2013-01-01

    A fiber reinforced core panel is formed from strips of plastics foam helically wound with layers of rovings to form webs which may extend in a wave pattern or may intersect transverse webs. Hollow tubes may replace foam strips. Axial rovings cooperate with overlying helically wound rovings to form a beam or a column. Wound roving patterns may vary along strips for structural efficiency. Wound strips may alternate with spaced strips, and spacers between the strips enhance web buckling strength. Continuously wound rovings between spaced strips permit folding to form panels with reinforced edges. Continuously wound strips are helically wrapped to form annular structures, and composite panels may combine both thermoset and thermoplastic resins. Continuously wound strips or strip sections may be continuously fed either longitudinally or laterally into molding apparatus which may receive skin materials to form reinforced composite panels.

  13. Seismic Stability of Reinforced Soil Slopes

    DEFF Research Database (Denmark)

    Tzavara, I.; Zania, Varvara; Tsompanakis, Y.; Psarropoulos, P.N.

    Over recent decades increased research interest has been observed on the dynamic response and stability issues of earth walls and reinforced soil structures. The current study aims to provide an insight into the dynamic response of reinforced soil structures and the potential of the geosynthetics...... to prevent the development of slope instability taking advantage of their reinforcing effect. For this purpose, a onedimensional (SDOF) model, based on Newmark’s sliding block model as well as a two-dimensional (plane-strain) dynamic finite-element analyses are conducted in order to investigate the...... impact of the most significant parameters involved, such as the flexibility of the sliding system, the mechanical properties of the soil and of the geosynthetics material, the frequency content of the excitation and the interface shear strength....

  14. Creep deformation characteristics of ductile discontinuous fiber reinforced composites

    Energy Technology Data Exchange (ETDEWEB)

    Biner, S.B.

    1993-10-01

    Role of material parameters and geometric parameters of ductile reinforcing phase on the creep deformation behavior of 20% discontinuously reinforced composite was numerically investigated including debonding and pull-out mechanisms. Results indicate that for rigidly bonded interfaces, the creep rate of the composite is not significantly influenced by the material properties and geometric parameters of the ductile reinforcing phase due to development of large hydrostatic stress and constrained deformation in the reinforcement. For debonding interfaces, the geometric parameters of the reinforcing phase are important; however, event with very weak interfacial behavior low composite creep rates can be achieved by suitable selection of the geometric parameters of the ductile reinforcing phase.

  15. Suboptimal choice in pigeons: Choice is primarily based on the value of the conditioned reinforcer rather than overall reinforcement rate.

    Science.gov (United States)

    Smith, Aaron P; Zentall, Thomas R

    2016-04-01

    Pigeons have sometimes shown a preference for a signaled 50% reinforcement alternative (leading half of the time to a stimulus that signaled 100% reinforcement and otherwise to a stimulus that signaled 0% reinforcement) over a 100% reinforcement alternative. We hypothesized that pigeons may actually be indifferent between the 2 alternatives with previous inconsistent preferences resulting in part from an artifact of the use of a spatial discrimination. In the present experiments, we tested the hypothesis that pigeons would be indifferent between alternatives that provide conditioned reinforcers of equal value. In Experiment 1, we used the signaled 50% reinforcement versus 100% reinforcement procedure, but cued the alternatives with shapes that varied in their spatial location from trial to trial. Consistent with the stimulus value hypothesis, the pigeons showed indifference between the alternatives. In Experiment 2, to confirm that the pigeons could discriminate between the shapes, we removed the discriminative function from the 50% reinforcement alternative and found a clear preference for the 100% reinforcement alternative. Finally, in Experiment 3, when we returned the discriminative function to the 50% reinforcement alternative and reduced the 100% reinforcement alternative to 50% reinforcement, we found a clear preference for the discriminative stimulus alternative. These results support the hypothesis that pigeons prefer the alternative with the conditioned reinforcer that best predicts reinforcement, whereas its frequency may be relatively unimportant. (PsycINFO Database Record PMID:26881902

  16. Root reinforcement of soils under compression

    Science.gov (United States)

    Schwarz, M.; Rist, A.; Cohen, D.; Giadrossich, F.; Egorov, P.; Büttner, D.; Stolz, M.; Thormann, J.-J.

    2015-10-01

    It is well recognized that roots reinforce soils and that the distribution of roots within vegetated hillslopes strongly influences the spatial distribution of soil strength. Previous studies have focussed on the contribution of root reinforcement under conditions of tension or shear. However, no systematic investigation into the contribution of root reinforcement to soils experiencing compression, such as the passive Earth forces at the toe of a landslide, is found in the literature. An empirical-analytical model (CoRoS) for the quantification of root reinforcement in soils under compression is presented and tested against experimental data. The CoRoS model describes the force-displacement behavior of compressed, rooted soils and can be used to provide a framework for improving slope stability calculations. Laboratory results showed that the presence of 10 roots with diameters ranging from 6 to 28 mm in a rectangular soil profile 0.72 m by 0.25 m increased the compressive strength of the soil by about 40% (2.5 kN) at a displacement of 0.05 m, while the apparent stiffness of the rooted soil was 38% higher than for root-free soil. The CoRoS model yields good agreement with experimentally determined values of maximum reinforcement force and compression force as a function of displacement. These results indicate that root reinforcement under compression has a major influence on the mechanical behavior of soil and that the force-displacement behavior of roots should be included in analysis of the compressive regimes that commonly are present in the toe of landslides.

  17. THE USE OF SWIMMER BARS AS SHEAR REINFORCEMENT IN REINFORCED CONCRETE BEAM

    Directory of Open Access Journals (Sweden)

    Moayyad Al-Nasra

    2013-01-01

    Full Text Available The behavior of reinforced concrete beams at failure by shear is distinctly different from their behavior by bending, which is considered to be unsafe mode of failure. The shear failure of beams is usually sudden without sufficient advanced warning and the diagonal cracks that develop due to excess shear forces are considerably wider than the flexural cracks. The cost and safety of shear reinforcement in reinforced concrete beams led to the study of other alternatives. Swimmer bar system is a new type of shear reinforcement. It is a small inclined bars, with its both ends bent horizontally for a short distance and welded to both top and bottom flexural steel reinforcement. Regardless of the number of swimmer bars used in each inclined plane, the swimmer bars form plane-crack interceptor system instead of bar-crack interceptor system when stirrups are used. Test results of several reinforced concrete beams will be presented. The effectiveness of the new swimmer bar system as related to the old stirrup system will be discussed. Beam deflection is also targeted experimentally in the lab. Several deflection measurements were taken to study the effect of using new swimmer bar system on deflection. Also the crack width of the tested reinforced concrete beams was monitored.

  18. Elaboration of fiber-reinforced metallic materials

    International Nuclear Information System (INIS)

    A bibliographic study on the elaboration of fiber reinforced metallic materials is presented in three parts: the theory of fiber reinforcement of metals in summarized, with emphasis on the mechanical and geometric factors which govern the behaviour and the performances to be expected from a given composite material; a second part is devoted to the study of the physical and chemical factors related to the structural stability of the material. Finally, the various processes of fabrication of such composites are presented and discussed. (author)

  19. On the beating of reinforcement pulp

    OpenAIRE

    Hiltunen, Eero

    2003-01-01

    The aim of this work was to gain a better understanding of the effect of reinforcement pulp beating on the strength of mechanical pulp-dominated paper. The main purpose of reinforcement pulp beating is to improve the runnability of paper. The first objective of this study was to maximize the runnability related strength properties by beating. It was assumed that the flaw-resisting ability of paper correlates with the runnability of the dry paper web. In-plane fracture properties were assumed ...

  20. Reinforcement learning improves behaviour from evaluative feedback

    Science.gov (United States)

    Littman, Michael L.

    2015-05-01

    Reinforcement learning is a branch of machine learning concerned with using experience gained through interacting with the world and evaluative feedback to improve a system's ability to make behavioural decisions. It has been called the artificial intelligence problem in a microcosm because learning algorithms must act autonomously to perform well and achieve their goals. Partly driven by the increasing availability of rich data, recent years have seen exciting advances in the theory and practice of reinforcement learning, including developments in fundamental technical areas such as generalization, planning, exploration and empirical methodology, leading to increasing applicability to real-life problems.

  1. Long Term Durability of Glass Reinforced Composites

    OpenAIRE

    Cain, Jason James

    2008-01-01

    This dissertation discusses topics related to the performance and long-term durability of glass-reinforced composites. The first portion of this dissertation describes work to assess the effect that post-curing has on widely used E-glass/vinyl-ester composites (E-glass/Derakane 510-A and E-glass/Derakane 8084). It is shown that post-curing can have significant positive effects on the initial material properties of glass-reinforced vinyl ester composites. Furthermore, the post-cure of 82Â...

  2. Reinforcement learning improves behaviour from evaluative feedback.

    Science.gov (United States)

    Littman, Michael L

    2015-05-28

    Reinforcement learning is a branch of machine learning concerned with using experience gained through interacting with the world and evaluative feedback to improve a system's ability to make behavioural decisions. It has been called the artificial intelligence problem in a microcosm because learning algorithms must act autonomously to perform well and achieve their goals. Partly driven by the increasing availability of rich data, recent years have seen exciting advances in the theory and practice of reinforcement learning, including developments in fundamental technical areas such as generalization, planning, exploration and empirical methodology, leading to increasing applicability to real-life problems. PMID:26017443

  3. Influence of Shear on Rotation Capacity of Reinforced Concrete Members Without Shear Reinforcement

    OpenAIRE

    Vaz Rodrigues, Rui; Muttoni, Aurelio; Fernández Ruiz, Miguel

    2010-01-01

    The influence of shear on the rotation capacity of one-way slabs without shear reinforcement is investigated in this paper by means of an experimental study. The experimental program consisted of 11 slab strips 8400 mm (331 in.) long and 450 mm (17.7 in.) thick with a flexural reinforcement ratio of 0.79%. The rotation capacity was investigated for various values of the shear span and for two types of flexural reinforcement (hot-rolled and cold-worked bars). The specimens developed shear fail...

  4. Reinforcement Overkill: Implications for Education of the Retarded

    Science.gov (United States)

    Forness, Steven R.; MacMillan, Donald L.

    1972-01-01

    Considered is the possibility that behavior modification methods with educable and trainable mentally handicapped children which utilize primitive reinforcement methods such as token economies are not necessary because the systematic use of social reinforcement might produce the same effect. (DB)

  5. Leaf spring made of fiber-reinforced resin

    Science.gov (United States)

    Hori, J.

    1986-01-01

    A leaf spring made of a matrix reinforced by at least two types of reinforcing fibers with different Young's modulus is described in this Japanese patent. At least two layers of reinforcing fibers are formed by partially arranging the reinforcing fibers toward the direction of the thickness of the leaf spring. A mixture of different types of reinforced fibers is used at the area of boundary between the two layers of reinforced fibers. The ratio of blending of each type of reinforced fiber is frequently changed to eliminate the parts where discontinuous stress may be applied to the leaf spring. The objective of this invention is to prevent the rapid change in Young's modulus at the boundary area between each layer of reinforced fibers in the leaf spring.

  6. Self-Reinforcement Effects: An Artifact of Social Standard Setting?

    Science.gov (United States)

    Hayes, Steven C.

    1985-01-01

    Two studies involving college students examined mechanisms responsible for observed self-reinforcement effects. Results seemed to support the view that self-reinforcement procedures work by setting a socially available standard against which performance can be evaluated. (CL)

  7. Production technology of high strength reinforcement rod

    Institute of Scientific and Technical Information of China (English)

    Yurev; A.; B.; Chinokalov; V.; Y.; Efimov; O.; Y.; Zezikov; M.; V.; Myskova; N.; V.

    2005-01-01

    At present JSC "ZSMK" is the largest producer of building reinforcement steel in Russia. One of the most essential conditions for holding our positions on this products market is the increase of assortment and quality of rolled metal.……

  8. Pigeons' Discounting of Probabilistic and Delayed Reinforcers

    Science.gov (United States)

    Green, Leonard; Myerson, Joel; Calvert, Amanda L.

    2010-01-01

    Pigeons' discounting of probabilistic and delayed food reinforcers was studied using adjusting-amount procedures. In the probability discounting conditions, pigeons chose between an adjusting number of food pellets contingent on a single key peck and a larger, fixed number of pellets contingent on completion of a variable-ratio schedule. In the…

  9. Dynamics of a reinforced viscoelastic plate

    Directory of Open Access Journals (Sweden)

    Igor V. Andrianov

    2006-01-01

    Full Text Available Oscillations and static bending deformation of a viscoelastic reinforced plate are considered. Analytical solutions are derived. An asymptotic technique, based on the homogenization method, is used for this purpose. In addition, a special perturbation approach is employed. An example is given for the purpose of illustration. The approximate analytical expressions are shown to adequately meet the requirements of optimal structural design.

  10. Origins of altered reinforcement effects in ADHD

    OpenAIRE

    Tripp Gail; Russell Vivienne A; Killeen Peter R; Johansen Espen; Wickens Jeff R; Tannock Rosemary; Williams Jonathan; Sagvolden Terje

    2009-01-01

    Abstract Attention-deficit/hyperactivity disorder (ADHD), characterized by hyperactivity, impulsiveness and deficient sustained attention, is one of the most common and persistent behavioral disorders of childhood. ADHD is associated with catecholamine dysfunction. The catecholamines are important for response selection and memory formation, and dopamine in particular is important for reinforcement of successful behavior. The convergence of dopaminergic mesolimbic and glutamatergic corticostr...

  11. Reinforcement Learning in Continuous Action Spaces

    NARCIS (Netherlands)

    Hasselt, H. van; Wiering, M.A.

    2007-01-01

    Quite some research has been done on Reinforcement Learning in continuous environments, but the research on problems where the actions can also be chosen from a continuous space is much more limited. We present a new class of algorithms named Continuous Actor Critic Learning Automaton (CACLA) that c

  12. Applications and Properties of Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Amit Rai1 ,

    2014-05-01

    Full Text Available In conventional concrete, micro-cracks develop before structure is loaded because of drying shrinkage and other causes of volume change. When the structure is loaded, the micro cracks open up and propagate because of development of such micro-cracks, results in inelastic deformation in concrete. Fibre reinforced concrete (FRC is cementing concrete reinforced mixture with more or less randomly distributed small fibres. In the FRC, a numbers of small fibres are dispersed and distributed randomly in the concrete at the time of mixing, and thus improve concrete properties in all directions. The fibers help to transfer load to the internal micro cracks. FRC is cement based composite material that has been developed in recent years. It has been successfully used in construction with its excellent flexural-tensile strength, resistance to spitting, impact resistance and excellent permeability and frost resistance. It is an effective way to increase toughness, shock resistance and resistance to plastic shrinkage cracking of the mortar. These fibers have many benefits. Steel fibers can improve the structural strength to reduce in the heavy steel reinforcement requirement. Freeze thaw resistance of the concrete is improved. Durability of the concrete is improved to reduce in the crack widths. Polypropylene and Nylon fibers are used to improve the impact resistance. Many developments have been made in the fiber reinforced concrete.

  13. CHOICE, DYNAMIC REINFORCEMENT, AND CHANGEOVER RESPONSE REQUIREMENT

    Directory of Open Access Journals (Sweden)

    JORGE A. BALDERRAMA

    2004-07-01

    Full Text Available Recent studies have shown that choice does not require steady state performance to show sensitivity toreinforcement. This idea was further explored in a choice situation in which a changeover responserequirement was manipulated. The parameters of the generalized matching law (Baum, 1974 were usedto assess changes in preference due to an increasing fixed-ratio changeover-response requirement. Theratio of reinforcement provided by two levers (27:1, 9:1, 3:1, 1:1, 1:3, 1:9, 1:27 was manipulated betweensessions to prevent steady state concurrent performance. In different conditions, the changeoverrequirement took on values of 1, 4, 8, 16 and 32 responses. The results showed local effects of reinforcementon choice behavior; from one reinforcer to the next, the distribution of responses favored thealternative associated with the highest probability of reinforcement. Although sensitivity to reinforcementdid not increase with increasing changeover response requirements, as the rats experienced thedynamic reinforcing environment along the experiment the value of the parameter s stabilized above 1.0.

  14. Reinforcing of chitosan phase with chitin nanofibrils

    Czech Academy of Sciences Publication Activity Database

    Tishchenko, Galina; Kelnar, Ivan; Kaprálková, Ludmila; Pavlova, Ewa; Vacková, Taťana; Brožová, Libuše; Strachota, Adam; Špírková, Milena; Bastl, Zdeněk; Carezzi, F.; Morganti, P.

    Roma : AIRI/Nanotec IT, 2013. s. 105. ISBN 978-88-6140-152-5. [NanotechItaly 2013 - Key Enabling Technologies for Responsible Innovation. 27.11.2013-29.11.2013, Venice] EU Projects: European Commission(XE) 315233 - N-CHITOPACK Institutional support: RVO:61389013 ; RVO:61388955 Keywords : chitin nanofibers * chitosan * reinforcing effect Subject RIV: CD - Macromolecular Chemistry

  15. Forming of UD fibre reinforced thermoplastics

    NARCIS (Netherlands)

    Haanappel, S.P.

    2013-01-01

    Composite materials are a serious competitor for lightweight metals used in the aerospace and automotive industry. Uni-directional (UD) carbon fibre reinforced thermoplastics are favoured due to their high specific strength and stiffness, but also their good toughness, impact and chemical resistance

  16. Analysis of Graphite-Reinforced Cementitious Composites

    Science.gov (United States)

    Vaughan, R. E.

    2002-01-01

    Strategically embedding graphite meshes in a compliant cementitious matrix produces a composite material with relatively high tension and compressive properties as compared to steel-reinforced structures fabricated from a standard concrete mix. Although these composite systems are somewhat similar, the methods used to analyze steel-reinforced composites often fail to characterize the behavior of their more advanced graphite-reinforced counterparts. This Technical Memorandum describes some of the analytical methods being developed to determine the deflections and stresses in graphite-reinforced cementitious composites. It is initially demonstrated that the standard transform section method fails to provide accurate results when the elastic moduli ratio exceeds 20. An alternate approach is formulated by using the rule of mixtures to determine a set of effective material properties for the composite. Tensile tests are conducted on composite samples to verify this approach. When the effective material properties are used to characterize the deflections of composite beams subjected to pure bending, an excellent agreement is obtained. Laminated composite plate theory is investigated as a means for analyzing even more complex composites, consisting of multiple graphite layers oriented in different directions. In this case, composite beams are analyzed using the laminated composite plate theory with material properties established from tensile tests. Then, finite element modeling is used to verify the results. Considering the complexity of the samples, a very good agreement is obtained.

  17. Seismic response of reinforced soil slopes

    DEFF Research Database (Denmark)

    Tzavara, Ioanna; Zania, Varvara; Tsompanakis, Yiannis; Psarropoulos, Prodromos

    2010-01-01

    parametric investigation to illustrate the impact of the crucial parameters of this approach. Subsequently, Newmark’s sliding block model is modified to account for the reinforcement forces in the calculation of seismic displacements. Finally, finite element analyses were performed and the numerical results...

  18. Limit analysis of solid reinforced concrete structures

    DEFF Research Database (Denmark)

    Larsen, Kasper Paaske

    2009-01-01

    Recent studies have shown that Semidefinite Programming (SDP) can be used effectively for limit analysis of isotropic cohesive-frictional continuums using the classical Mohr-Coulomb yield criterion. In this paper we expand on this previous research by adding reinforcement to the model and a solid...

  19. Nonlinear modelling of reinforced concrete structures

    OpenAIRE

    Bairán García, Jesús Miguel

    2009-01-01

    Non-linear modelling of structures is a crucial tool in order to understand complex structural behaviour, improve new design and to face the problem of assuring specific performance levels under complex loading. In this paper three main research lines are described which focus on different aspects of nonlinear modelling of reinforced concrete structures and to improve knowledge of the material behaviour.

  20. Repairing reinforced concrete slabs using composite layers

    International Nuclear Information System (INIS)

    There are several strengthening methods for rehabilitation of RC structural elements. The efficiency of these methods has been demonstrated by many researchers. Due to their mechanical properties, using fibrous materials in rehabilitation applications is growing fast. Therefore, this study presents rehabilitation of slabs in such a way that plain concrete layers on top, on bottom, on the entire cross section are replaced by reinforced concrete layers. In order to reinforce the concrete, Polypropylene (PP) and steel fibers were used by 0.5%, 1% and 2% fiber volume fractions. Nineteen slabs were studied under flexural loadings and fibrous material effects on the initial crack force, the maximum loading carrying capacity, absorbed energy and ductility were investigated. The obtained results demonstrated that increasing the fiber volume fraction or using reinforced concrete layer on top, bottom, or at the entire cross section of the slabs not only always leads to improvement in the slab performance, but also sometimes debilitates the slab performance. Hence, this study will propose the best positioning of reinforced concrete layer, fiber volume fraction and fiber type to achieve the best flexural performance of slabs. - Highlights: • Using PP fibers at the bottom layer led to the best slab performance in bending. • Using steel fiber at the top layer and entire cross-section led to the best slab performance. • Maximum increase in the initial crack force and loading were obtained at 2% steel fiber. • Maximum increase in the initial crack force and loading were obtained at 1% PP fiber

  1. Reinforcement versus fluidization in cytoskeletal mechanoresponsiveness.

    Directory of Open Access Journals (Sweden)

    Ramaswamy Krishnan

    Full Text Available Every adherent eukaryotic cell exerts appreciable traction forces upon its substrate. Moreover, every resident cell within the heart, great vessels, bladder, gut or lung routinely experiences large periodic stretches. As an acute response to such stretches the cytoskeleton can stiffen, increase traction forces and reinforce, as reported by some, or can soften and fluidize, as reported more recently by our laboratory, but in any given circumstance it remains unknown which response might prevail or why. Using a novel nanotechnology, we show here that in loading conditions expected in most physiological circumstances the localized reinforcement response fails to scale up to the level of homogeneous cell stretch; fluidization trumps reinforcement. Whereas the reinforcement response is known to be mediated by upstream mechanosensing and downstream signaling, results presented here show the fluidization response to be altogether novel: it is a direct physical effect of mechanical force acting upon a structural lattice that is soft and fragile. Cytoskeletal softness and fragility, we argue, is consistent with early evolutionary adaptations of the eukaryotic cell to material properties of a soft inert microenvironment.

  2. High-performance fiber reinforced polymers

    International Nuclear Information System (INIS)

    New fibers which are stiffer than fiberglas have resulted in advanced reinforced plastics. A review is presented of matrix and fiber materials; the latter includes glass, boron, carbon, and organic (PRD-49) fibers. Fabrication (both primary and secondary) and properties of these composites are next reviewed. Environmental degradation is also considered. (15 tables, 12 fig, 43 references.) (U.S.)

  3. Corrosion and Cracking of Reinforced Concrete

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Modelling of the deterioration of reinforced concrete has in recent years changed from being a deterministic modelling based on experience to be stochastic modelling based on sound and consistent physical, chemical and mechanical principles. In this paper is presented a brief review of modern mod...... for time to initial corrosion, time to initial cracking, and time to a given crack width may be obtained....

  4. Nonwoven glass fiber mat reinforces polyurethane adhesive

    Science.gov (United States)

    Roseland, L. M.

    1967-01-01

    Nonwoven glass fiber mat reinforces the adhesive properties of a polyurethane adhesive that fastens hardware to exterior surfaces of aluminum tanks. The mat is embedded in the uncured adhesive. It ensures good control of the bond line and increases the peel strength.

  5. Exhaust System Reinforced by Jet Flow

    DEFF Research Database (Denmark)

    Pedersen, Lars Germann; Nielsen, Peter V.

    Since 1985 the University of Aalborg and Nordfab A/S have been working on an exhaust principle which is quite different from traditional exhaust systems. The REEXS principle (Reinforced Exhaust System), which originally was designed for the agricultural sector, is particularly well-suited for ind...

  6. Adaptable bandwidth planning using reinforcement learning

    Directory of Open Access Journals (Sweden)

    Dirk Hetzer

    2006-08-01

    Full Text Available In order to improve the bandwidth allocation considering feedback of operational environment, adaptable bandwidth planning based on reinforcement learning is proposed. The approach is based on new constrained scheduling algorithms controlled by reinforcement learning techniques. Different constrained scheduling algorithms,, such as "conflict free scheduling with minimum duration", "partial displacement" and "pattern oriented scheduling" are defined and implemented. The scheduling algorithms are integrated into reinforcement learning strategies. These strategies include: - Q-learning for selection of optimal planning schedule using Q-values; - Informed Q-learning for exploitation and handling of prior-knowledge (patterns of network behaviour; - Relational Q-learning for improving of bandwidth allocation policies dynamically in operational networks considering actual network performance data. Scenarios based on integration of the scheduling algorithms and reinforcement learning techniques in the experimental monitoring and bandwidth planning system called QORE (QoS and resource optimisation are given. The proposed adaptable bandwidth planning is required for more efficient usage of network resources.

  7. Stigmergy in multi-agent reinforcement learning

    OpenAIRE

    Aras, Raghav; Dutech, Alain; Charpillet, François

    2004-01-01

    http://www.computer.org In this paper, we describe how certain aspects of the biological phenomena of stigmergy can be imported into multi-agent reinforcement learning (MARL), with the purpose of better enabling coordination of agent actions and speeding up learning. In particular, we detail how these stigmergic aspects can be used to define an inter-agent communication framework.

  8. Food Reinforcement and Eating: A Multilevel Analysis

    Science.gov (United States)

    Epstein, Leonard H.; Leddy, John J.; Temple, Jennifer L.; Faith, Myles S.

    2007-01-01

    Eating represents a choice among many alternative behaviors. The purpose of this review is to provide an overview of how food reinforcement and behavioral choice theory are related to eating and to show how this theoretical approach may help organize research on eating from molecular genetics through treatment and prevention of obesity. Special…

  9. Reinforced Readiness Requisites from Theory to Practice

    Science.gov (United States)

    Speiss, Madeleine F.; And Others

    This booklet is an instructional aid for teacher trainers. Its aim is to help trainers familiarize teachers with the theory and proper use of the Reinforced Readiness Requisites (RRR) program, a series of 145 lessons designed to give standard kindergarten and first grade entry and reading readiness skills to Mexican-American and Indian children.…

  10. Self-compacting fibre-reinforced concrete

    NARCIS (Netherlands)

    Grunewald, S.; Walraven, J.C.

    2001-01-01

    The project 'self-compacting fibre-reinforced concrete (SCFRC)' is part of the Dutch STW/PPM program - 'cement-bonded materials' - DCT.4010. Subproject III to which the project ,SCFRC' belongs deals with the development of new high performance concretes. The project 'SCFRC' aims at investigating the

  11. Reinforcing Variability in Adolescents with Autism.

    Science.gov (United States)

    Miller, Neal; Neuringer, Allen

    2000-01-01

    Five adolescents with autism, 5 control participants, and 4 child controls received rewards for varying their sequences of responses while playing a computer game. In preceding and following phases, rewards were provided at approximately the same rate but were independent of variability. When reinforced, variability increased significantly in all…

  12. Efficient abstraction selection in reinforcement learning

    NARCIS (Netherlands)

    Seijen, H. van; Whiteson, S.; Kester, L.

    2013-01-01

    This paper introduces a novel approach for abstraction selection in reinforcement learning problems modelled as factored Markov decision processes (MDPs), for which a state is described via a set of state components. In abstraction selection, an agent must choose an abstraction from a set of candida

  13. Flexural strength enhancement of confined reinforced concrete columns

    OpenAIRE

    Pam, HJ; Ho, JCM

    2001-01-01

    As part of a continuing research study, this paper proposes a new design aid to calculate the actual moment capacity of confined reinforced concrete columns. Up to now the moment capacity of a reinforced concrete column is calculated based on the code's guidelines for an unconfined section. As most reinforced concrete columns contain transverse or confining reinforcement, which will enhance the column moment capacity, the actual moment capacity will be much higher than the unconfined moment c...

  14. Repair and protection of concrete structures damaged by reinforcement corrosion

    OpenAIRE

    Likar, Andrej

    2006-01-01

    The present work is focused on repair of concrete structures damaged by reinforcement corrosion. First part describes properties of primary components in concrete (cement, water, aggregate). Further are described mechanical properties of concrete and reinforcement and their compatibility. Second part introduces kinds of processes which causes corrosion of reinforcement in concrete. There are two emphasized chemical processes which cause corrosion of reinforcement, carbonation and chloride dif...

  15. Tensile performance of braided composite rods for concrete reinforcement

    OpenAIRE

    Pereira, Cristiana Gonilho; Fangueiro, Raúl; Jalali, Said; Araújo, Mário Duarte de; Marques, P.

    2008-01-01

    The current work is concerned with the development of braided composite rods for civil engineering applications, namely for concrete internal reinforcement, as a steel substitute. The research study aims at understanding the tensile behaviour of composite rods reinforced by a textile structure – braided structure with core reinforcement. Seven types of braided composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided structure. Eglass, car...

  16. Braided composite rods to reinforce concrete subjected to aggressive environments

    OpenAIRE

    Pereira, Cristiana Gonilho; Fangueiro, Raúl; Jalali, Said; Marques, P.; Araújo, Mário Duarte de

    2008-01-01

    The current work is concerned with the development of braided composite rods for civil engineering applications, namely for concrete internal reinforcement, as a steel substitute. The research study aims at understanding the tensile behaviour of composite rods reinforced by a textile structure – braided structure with core reinforcement. Seven types of braided composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided structure. E-glass, ca...

  17. How to teach a pigeon to maximize overall reinforcement rate

    OpenAIRE

    Heyman, Gene M.; Tanz, Lawrence

    1995-01-01

    In two experiments deviations from matching earned higher overall reinforcement rates than did matching. In Experiment 1 response proportions were calculated over a 360-response moving average, updated with each response. Response proportions that differed from the nominal reinforcement proportions, by a criterion that was gradually increased, were eligible for reinforcement. Response proportions that did not differ from matching were not eligible for reinforcement. When the deviation require...

  18. Effect of hybrid fiber reinforcement on the cracking process in fiber reinforced cementitious composites

    DEFF Research Database (Denmark)

    Pereira, Eduardo B.; Fischer, Gregor; Barros, Joaquim A.O.

    2012-01-01

    tensile deformations in the composite, the fibers with different geometrical and mechanical properties restrain the propagation and further development of cracking at different scales from the micro- to the macro-scale. The optimized design of the fiber reinforcing systems requires the objective......The simultaneous use of different types of fibers as reinforcement in cementitious matrix composites is typically motivated by the underlying principle of a multi-scale nature of the cracking processes in fiber reinforced cementitious composites. It has been hypothesized that while undergoing...... materials is carried out by assessing directly their tensile stress-crack opening behavior. The efficiency of hybrid fiber reinforcements and the multi-scale nature of cracking processes are discussed based on the experimental results obtained, as well as the micro-mechanisms underlying the contribution of...

  19. Characterization of reinforced concrete beams strengthened by steel reinforced polymer and grout (SRP and SRG) composites

    International Nuclear Information System (INIS)

    The use of externally bonded steel reinforced polymer (SRP) and steel reinforced grout (SRG) is a promising new technology for increasing flexural, compressive, and shear capacities of reinforced concrete (RC) members. The flexural performance of RC beams with externally bonded SRP and SRG has been investigated experimentally using four-point bending. The material constants for single-ply SRP and SRG were experimentally determined from coupon tensile tests and torsion tests. Analytical models based on the first-order and higher-order shear deformation theories have been developed to predict the behavior of the retrofitted RC beams. Comparisons between the analytical models and the experimental results show a good correlation for the midspan deflection until the reinforcing steel reaches the plastic region

  20. REPAIR AND STRENGTHENING OF REINFORCED CONCRETE BEAMS USING FIBRE REINFORCED POLIMER (FRP) MATERIALS

    OpenAIRE

    ÇETİNKAYA, Nihat; Kaplan, Hasan; Ş. Murat ŞENEL

    2004-01-01

    The use of Fibre Reinforced Polimer (FRP ) materials for the repair and strengthening of Reinforced Concrete structures has become widespread recently. FRP materials are being prefered because they have very high tensile strength, resistance to corrosion and they do not affect the use of the building during the repair and strengthening process. Four reinfoced concrete beams repaired and strengthened with FRP materials have been used in this study which were performed at Pamukkale University-F...

  1. Analysis of reinforced concrete beams without shear reinforcement using non-local microplane model

    OpenAIRE

    Ozbolt, Josko; Eligehausen, Rolf

    1991-01-01

    The shear resistance of reinforced concrete beams without shear reinforcement is studied using the non-local microplane model and plane stress finite elements. The main objective of the present work is the study of the size effect. Calculated failure loads for geometrically similar specimens of four different sizes are compared with test data and the recently proposed size effect law. Results of the analysis as well as test results exhibit significant size effect. Observed failure is of the b...

  2. Influence of capacity design principles on required amount of reinforcement of a reinforced concrete

    OpenAIRE

    Hrastnik, Miha

    2012-01-01

    The thesis deals with a design of a six-storey reinforced concrete building with a two-storey basement. The main objective was to evaluate the difference in the required amount of reinforcement, if determined based on the design seismic action with consideration of the provisions of SIST EN 1992 standard or with consideration of provisions of SIST EN 1992 and 1998. The latter aproach increases the design safety due to more restrictive design requirements and due to the prescribed ...

  3. Uplift of Symmetrical Anchor Plates by Using Grid-Fixed Reinforced Reinforcement in Cohesionless Soil

    Institute of Scientific and Technical Information of China (English)

    Hamed Niroumand; Khairul Anuar Kassim

    2014-01-01

    Uplift response of symmetrical anchor plates with and without grid fixed reinforced (GFR) reinforcement was evaluated in model tests and numerical simulations by Plaxis. Many variations of reinforcement layers were used to reinforce the sandy soil over symmetrical anchor plates. In the current research, different factors such as relative density of sand, embedment ratios, and various GFR parameters including size, number of layers, and the proximity of the layer to the symmetrical anchor plate were investigated in a scale model. The failure mechanism and the associated rupture surface were observed and evaluated. GFR, a tied up system made of fiber reinforcement polymer (FRP) strips and end balls, was connected to the geosynthetic material and anchored into the soil. Test results showed that using GFR reinforcement significantly improved the uplift capacity of anchor plates. It was found that the inclusion of one layer of GFR, which rested directly on the top of the anchor plate, was more effective in enhancing the anchor capacity itself than other methods. It was found that by including GFR the uplift response was improved by 29%. Multi layers of GFR proved more effective in enhancing the uplift capacity than a single GFR reinforcement. This is due to the additional anchorage provided by the GFR at each level of reinforcement. In general, the results show that the uplift capacity of symmetrical anchor plates in loose and dense sand can be significantly increased by the inclusion of GFR. It was also observed that the inclusion of GFR reduced the requirement for a large L/D ratio to achieve the required uplift capacity. The laboratory and numerical analysis results are found to be in agreement in terms of breakout factor and failure mechanism pattern.

  4. Glass Fiber Reinforced Polymer Bars as the Top Mat Reinforcement for Bridge Decks

    OpenAIRE

    DeFreese, James Michael

    2001-01-01

    The primary objective of this research was to experimentally investigate material and bond properties of three different types of fiber reinforced polymer (FRP) bars, and determine their effect on the design of a bridge deck using FRP bars as the top mat of reinforcement. The properties evaluated include the tensile strength, modulus of elasticity, bond behavior, and maximum bond stress. The experimental program included 47 tensile tests and 42 beam end bond tests performed with FRP bars. ...

  5. Choice between reliable and unreliable reinforcement alternatives revisited: Preference for unreliable reinforcement

    OpenAIRE

    Belke, Terry W; Spetch, Marcia L

    1994-01-01

    Pigeons' choices between a reliable alternative that always provided food after a delay (i.e., 100% reinforcement) and an unreliable one that provided food or blackout equally often after a delay (i.e., 50% reinforcement) was studied using a discrete-trials concurrent-chains procedure modified to prevent choice between alternatives following a blackout outcome. Initial links were fixed-ratio 1 schedules, and terminal links were fixed-time schedules. Stimuli presented during the terminal-link ...

  6. AN INVESTIGATION OF DIFFERENTIAL REINFORCEMENT OF ALTERNATIVE BEHAVIOR WITHOUT EXTINCTION

    OpenAIRE

    Athens, Elizabeth S; Vollmer, Timothy R

    2010-01-01

    We manipulated relative reinforcement for problem behavior and appropriate behavior using differential reinforcement of alternative behavior (DRA) without an extinction component. Seven children with developmental disabilities participated. We manipulated duration (Experiment 1), quality (Experiment 2), delay (Experiment 3), or a combination of each (Experiment 4), such that reinforcement favored appropriate behavior rather than problem behavior even though problem behavior still produced rei...

  7. Locus of Control of Reinforcement and Responsiveness to Social Influence.

    Science.gov (United States)

    Doctor, Ronald M.; Marziani, A. William

    Rotter's (1966) "control of reinforcement" construct is a dimension of belief or expectancy about the locus of reinforcing consequences for behavior. A generalized disposition is represented which ascribes reinforcement contingencies to either "external" (and, hence, uncontrollable) factors or to "internal" sources in which case the individual…

  8. Within-Session Delay-of-Reinforcement Gradients

    Science.gov (United States)

    Reilly, Mark P.; Lattal, Kennon A.

    2004-01-01

    Within-session delay-of-reinforcement gradients were generated with pigeons by progressively increasing delays to reinforcement within each session. In Experiment 1, the effects of imposing progressive delays on variable-interval and fixed-interval schedules were investigated while controlling for simultaneous decreases in reinforcer rate across…

  9. Effects of Video Games as Reinforcers for Computerized Addition Performance.

    Science.gov (United States)

    Axelrod, Saul; And Others

    1987-01-01

    Four 2nd-grade students completed addition problems on a computer, using video games as reinforcers. Two variable ratio schedules of reinforcement failed to increase student accuracy or the rate of correct responses. In a no-games reinforcement condition, students had more opportunities to respond and had a greater number of correct answers.…

  10. On the distribution of the limit proportion for a two-color, randomly reinforced urn with equal reinforcement distributions

    OpenAIRE

    Aletti, Giacomo; May, Caterina; Secchi, Piercesare

    2007-01-01

    We consider a two-color, randomly reinforced urn with equal reinforcement distributions and we characterize the distribution of the urn's limit proportion as the unique continuous solution of a functional equation involving unknown probability distributions on [0, 1].

  11. Prediction of reinforcement corrosion using corrosion induced cracks width in corroded reinforced concrete beams

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Inamullah; François, Raoul [Université de Toulouse, UPS, INSA, LMDC (Laboratoire Matériaux et Durabilité des Constructions), 135, Avenue de Rangueil, F-31077 Toulouse (France); Castel, Arnaud [Centre for Infrastructure Engineering and Safety, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW (Australia)

    2014-02-15

    This paper studies the evolution of reinforcement corrosion in comparison to corrosion crack width in a highly corroded reinforced concrete beam. Cracking and corrosion maps of the beam were drawn and steel reinforcement was recovered from the beam to observe the corrosion pattern and to measure the loss of mass of steel reinforcement. Maximum steel cross-section loss of the main reinforcement and average steel cross-section loss between stirrups were plotted against the crack width. The experimental results were compared with existing models proposed by Rodriguez et al., Vidal et al. and Zhang et al. Time prediction models for a given opening threshold are also compared to experimental results. Steel cross-section loss for stirrups was also measured and was plotted against the crack width. It was observed that steel cross-section loss in the stirrups had no relationship with the crack width of longitudinal corrosion cracks. -- Highlights: •Relationship between crack and corrosion of reinforcement was investigated. •Corrosion results of natural process and then corresponds to in-situ conditions. •Comparison with time predicting model is provided. •Prediction of load-bearing capacity from crack pattern was studied.

  12. RETROFITTING OF REINFORCED CONCRETE BEAMS USING FIBRE REINFORCED POLYMER (FRP COMPOSITES – A REVIEW

    Directory of Open Access Journals (Sweden)

    Namasivayam Aravind

    2013-06-01

    Full Text Available Rehabilitation and strengthening of old structures using advanced materials is a contemporary research in the field of Structural Engineering. During past two decades, much research has been carried out on shear and flexural strengthening of reinforced concrete beams using different types of fibre reinforced polymers and adhesives. Strengthening of old structures is necessary to obtain an expected life span. Life span of Reinforced Concrete (RC structures may be reduced due to many reasons, such as deterioration of concrete and development of surface cracks due to ingress of chemical agents, improper design and unexpected external lateral loads such as wind or seismic forces acting on a structure, which are also the reasons for failure of structural members. The superior properties of polymer composite materials like high corrosion resistance, high strength, high stiffness, excellent fatigue performance and good resistance to chemical attack etc., has motivated the researchers and practicing engineers to use the polymer composites in the field of rehabilitation of structures. This paper reviews fourteen articles on rehabilitation of reinforced concrete (RC beams. The paper reviews the different properties of Glass Fibre Reinforced Polymer (GFRP and Carbon Fibre Reinforced Polymer (CFRP composites and adhesives, influence of dimensions of beams and loading rate causing failure. The paper proposes an enhanced retrofitting technique for flexural members and to develop a new mathematical model.

  13. Prediction of reinforcement corrosion using corrosion induced cracks width in corroded reinforced concrete beams

    International Nuclear Information System (INIS)

    This paper studies the evolution of reinforcement corrosion in comparison to corrosion crack width in a highly corroded reinforced concrete beam. Cracking and corrosion maps of the beam were drawn and steel reinforcement was recovered from the beam to observe the corrosion pattern and to measure the loss of mass of steel reinforcement. Maximum steel cross-section loss of the main reinforcement and average steel cross-section loss between stirrups were plotted against the crack width. The experimental results were compared with existing models proposed by Rodriguez et al., Vidal et al. and Zhang et al. Time prediction models for a given opening threshold are also compared to experimental results. Steel cross-section loss for stirrups was also measured and was plotted against the crack width. It was observed that steel cross-section loss in the stirrups had no relationship with the crack width of longitudinal corrosion cracks. -- Highlights: •Relationship between crack and corrosion of reinforcement was investigated. •Corrosion results of natural process and then corresponds to in-situ conditions. •Comparison with time predicting model is provided. •Prediction of load-bearing capacity from crack pattern was studied

  14. Random Time Dependent Resistance Analysis on Reinforced Concrete Structures

    Institute of Scientific and Technical Information of China (English)

    GUAN Chang-sheng; WU Ling

    2002-01-01

    The analysis method on random time dependence of reinforced concrete material is introduced,the effect mechanism on reinforced concrete are discussed, and the random time dependence resistance of reinforced concrete is studied. Furthermore, the corrosion of steel bar in reinforced concrete structures is analyzed. A practical statistical method of evaluating the random time dependent resistance, which includes material, structural size and calculation influence, is also established. In addition, an example of predicting random time dependent resistance of reinforced concrete structural element is given.

  15. A model for discriminating reinforcers in time and space.

    Science.gov (United States)

    Cowie, Sarah; Davison, Michael; Elliffe, Douglas

    2016-06-01

    Both the response-reinforcer and stimulus-reinforcer relation are important in discrimination learning; differential responding requires a minimum of two discriminably-different stimuli and two discriminably-different associated contingencies of reinforcement. When elapsed time is a discriminative stimulus for the likely availability of a reinforcer, choice over time may be modeled by an extension of the Davison and Nevin (1999) model that assumes that local choice strictly matches the effective local reinforcer ratio. The effective local reinforcer ratio may differ from the obtained local reinforcer ratio for two reasons: Because the animal inaccurately estimates times associated with obtained reinforcers, and thus incorrectly discriminates the stimulus-reinforcer relation across time; and because of error in discriminating the response-reinforcer relation. In choice-based timing tasks, the two responses are usually highly discriminable, and so the larger contributor to differences between the effective and obtained reinforcer ratio is error in discriminating the stimulus-reinforcer relation. Such error may be modeled either by redistributing the numbers of reinforcers obtained at each time across surrounding times, or by redistributing the ratio of reinforcers obtained at each time in the same way. We assessed the extent to which these two approaches to modeling discrimination of the stimulus-reinforcer relation could account for choice in a range of temporal-discrimination procedures. The version of the model that redistributed numbers of reinforcers accounted for more variance in the data. Further, this version provides an explanation for shifts in the point of subjective equality that occur as a result of changes in the local reinforcer rate. The inclusion of a parameter reflecting error in discriminating the response-reinforcer relation enhanced the ability of each version of the model to describe data. The ability of this class of model to account for a

  16. On monolithic stability and reinforcement analysis of high arch dams

    Institute of Scientific and Technical Information of China (English)

    YANG; Qiang; CHEN; YingRu; LIU; YaoRu

    2007-01-01

    Monolithic stability safety and reinforcement based on monolithic stability are very important for arch dam design.In this paper,the issue is addressed based on deformation reinforcement theory.In this approach,plastic complementary energy norm can be taken as safety Index for monolithic stability.According to deformation reinforcement theory,the areas where unbalanced force exists require reinforcement,and the required reinforcement forces are just the unbalanced forces with opposite direction.Results show that areas with unbalanced force mainly concentrate in dam-toes,dam-heels and faults.

  17. Glass FRP reinforcement in rehabilitation of concrete marine infrastructure

    International Nuclear Information System (INIS)

    Fiber reinforced polymer (FRP) reinforcements for concrete structures are gaining wide acceptance as a suitable alternative to steel reinforcements. The primary advantage is that they do not suffer corrosion and hence they promise to be more durable in environments where steel reinforced concrete has a limited life span. Concrete wharves and jetties are examples of structures subjected to such harsh environments and represent the general class of marine infrastructure in which glass FRP (GFRP) reinforcement should be used for improved durability and service life. General design considerations which make glass FRP suitable for use in marine concrete rehabilitation projects are discussed. A case study of recent wharf rehabilitation project in Canada is used to reinforce these considerations. The structure consisted of a GFRP reinforced concrete deck panel and steel - GFRP hybrid reinforced concrete pile cap. A design methodology is developed for the hybrid reinforcement design and verified through testing. The results of a field monitoring program are used to establish the satisfactory field performance of the GFRP reinforcement. The design concepts presented in the paper are applicable to many concrete marine components and other structures where steel reinforcement corrosion is a problem. (author)

  18. Taste and food reinforcement in non-overweight youth.

    Science.gov (United States)

    Epstein, Leonard H; Carr, Katelyn A; Scheid, Jennifer L; Gebre, Eden; O'Brien, Alexis; Paluch, Rocco A; Temple, Jennifer L

    2015-08-01

    Food reinforcement is related to increased energy intake, cross-sectionally related to obesity and prospectively related to weight gain in children, adolescents and adults. There is very limited research on how different characteristics of food are related to food reinforcement, and none on how foods from different taste categories (sweet, savory, salty) are related to food reinforcement. We tested differences in food reinforcement for favorite foods in these categories and used a reinforcing value questionnaire to assess how food reinforcement was related to energy intake in 198 non-overweight 8- to 12-year-old children. Results showed stronger food reinforcement for sweet foods in comparison to savory or salty foods. In multiple regression models, controlling for child sex, minority status and age, average reinforcing value was related to total energy and fat intake, and reinforcing value of savory foods was related to total energy and fat intake. Factor analysis showed one factor, the motivation to eat, rather than separate factors based on different taste categories. Liking ratings were unrelated to total energy intake. These results suggest that while there are differences in the reinforcing value of food by taste groups, there are no strong differences in the relationship between reinforcing value of food by taste groups and energy or macronutrient intake. PMID:25891040

  19. Influences of Reinforcement on Differential Drying Shrinkage of Concrete

    Institute of Scientific and Technical Information of China (English)

    GAO Xiaojian; QU Guangbin; ZHANG Ailian

    2012-01-01

    Shrinkage strain of concrete specimen with different reinforcement configuration was measured at various depths from the exposed surface by using several pairs of displacement sensors.Only one surface of the concrete specimen was exposed to dry condition during the experiment.The results show that differential shrinkage strain occurs in both plain and steel reinforced concrete specimens according to depths from the exposed surface.A higher reinforcement ratio results in a greater restraint against shrinkage of concrete nearby reinforcement rebar and a worse differential shrinkage strain distribution in the concrete specimen.The restraint against shrinkage of concrete becomes lower with the increasing distance from reinforcement rebar.Under the same reinforcement arrangement,a higher free shrinkage of concrete leads to a stronger restraint against shrinkage and a higher shrinkage stress formation in local concrete.The relationship between shrinkage strain and reduction of relative humidity in reinforced concrete structure is far different from that in plain concrete.

  20. Penetration resistance of reinforced concrete containment structures

    International Nuclear Information System (INIS)

    Containment structures not only provide a leak tight barrier, but also play a role in ensuring that the structures can withstand the impact load from projectile impacts or internal plant accidents. In assessing the containment structures of nuclear power plants, predicting the characteristics of impact resistance in relation to design and safety considerations is relevant. This investigation proposes a simple but effective method of performing numerical analysis on perforation resistance of reinforced concrete containment structures. In this work, normal and oblique impacting is considered to examine the residual velocity and impact phenomena of an ogive-nose steel projectile with various impact velocities against a reinforced concrete slab. Additionally, a phase diagram is devised to describe the ballistic terminal phenomena of projectile and target. This model could assess the resistance to penetration to results in the optimum design of the containment structures in nuclear power plants

  1. The technologically-reinforced natural radioactivity

    International Nuclear Information System (INIS)

    Technologically-reinforced natural radioactivity comes from mining industries, geological resources and ores de-confinement, and from separation, purification, transformation and use of by-products or products. Partly based on a survey and questionnaires sent to industrial organisations, this report proposes a large and detailed overview of this kind of radioactivity for different sectors or specific activities: the French phosphate sector, the international rare Earth and heavy ores sector, the French monazite sector, the ilmenite sector, the French and international zirconium sector, the non-ferrous metal sector, the international and French drinkable, mineral and spring water sector, the international wastewater sector, the French drilling sector, the international and French geothermal sector, the international and French gas and oil sector, the international and French coal sector, the international and French biomass sector, the international and French paper-making industry, and the management of wastes with technologically-reinforced natural radioactivity in France

  2. Two layer structure for reinforcing pothole repair

    Science.gov (United States)

    Yuan, Wei; Yuan, Kuo-Yao; Zou, Linhua; Yang, Jenn-Ming; Ju, Jiann-Wen; Kao, Wei; Carlson, Larry

    2013-04-01

    We have applied dicyclopentadiene (DCPD) resin for reinforcing pothole patch materials due to its unique properties - low cost, low viscosity at beginning and ultra-toughness after curing, chemical compatibility with tar, tunable curing profile through catalyst design. In this paper, we have designed a two layer structure - well compacted base layer and DCPD reinforced 1-1.5" top layer - for pothole repair. By choosing two graded asphalt mixes, a porous top layer and fully compacted base layer was prepared after compaction and ready for DCPD resin infiltration. The DCPD curing and infiltration profile within this porous top layer was measured with thermocouples. The rutting resistance was tested with home-made wheel rutter. The cage effect due to the p-DCPD wrapping was characterized with wheel penetration test. The results showed that this two layer structure pothole repair has greatly improved properties and can be used for pothole repair to increase the service life.

  3. Online support vector regression for reinforcement learning

    Institute of Scientific and Technical Information of China (English)

    Yu Zhenhua; Cai Yuanli

    2007-01-01

    The goal in reinforcement learning is to learn the value of state-action pair in order to maximize the total reward. For continuous states and actions in the real world, the representation of value functions is critical. Furthermore, the samples in value functions are sequentially obtained. Therefore, an online support vector regression (OSVR) is set up, which is a function approximator to estimate value functions in reinforcement learning. OSVR updates the regression function by analyzing the possible variation of support vector sets after new samples are inserted to the training set. To evaluate the OSVR learning ability, it is applied to the mountain-car task. The simulation results indicate that the OSVR has a preferable convergence speed and can solve continuous problems that are infeasible using lookup table.

  4. Reinforcement Learning Based on Active Learning Method

    CERN Document Server

    Sagha, Hesam; Khasteh, Hosein; Kiaei, Ali Akbar

    2010-01-01

    In this paper, a new reinforcement learning approach is proposed which is based on a powerful concept named Active Learning Method (ALM) in modeling. ALM expresses any multi-input-single-output system as a fuzzy combination of some single-input-singleoutput systems. The proposed method is an actor-critic system similar to Generalized Approximate Reasoning based Intelligent Control (GARIC) structure to adapt the ALM by delayed reinforcement signals. Our system uses Temporal Difference (TD) learning to model the behavior of useful actions of a control system. The goodness of an action is modeled on Reward- Penalty-Plane. IDS planes will be updated according to this plane. It is shown that the system can learn with a predefined fuzzy system or without it (through random actions).

  5. Early Loaded Single Implant Reinforced Mandibular Overdenture.

    Science.gov (United States)

    Nischal, K; Chowdhary, R

    2016-01-01

    Rehabilitating atrophied mandible with two-implant supported denture is a common treatment modality for implant retained removable overdenture in mandible. This paper aims to design a treatment modality where single implant reinforced overdenture is fabricated for a severely atrophied mandibular ridge with early loading protocol. Results of studies have shown that a single implant mandibular overdenture significantly increases the satisfaction and quality of life of patients with edentulism. Midline fracture of the prosthesis is the most common complication related to single implant and two-implant retained mandibular overdentures. To manage such complication, a thin metal mesh is used to reinforce the overdenture and also to make the prostheses lighter and cost effective as compared to conventional cast metal framework. PMID:27403350

  6. Early Loaded Single Implant Reinforced Mandibular Overdenture

    Directory of Open Access Journals (Sweden)

    K. Nischal

    2016-01-01

    Full Text Available Rehabilitating atrophied mandible with two-implant supported denture is a common treatment modality for implant retained removable overdenture in mandible. This paper aims to design a treatment modality where single implant reinforced overdenture is fabricated for a severely atrophied mandibular ridge with early loading protocol. Results of studies have shown that a single implant mandibular overdenture significantly increases the satisfaction and quality of life of patients with edentulism. Midline fracture of the prosthesis is the most common complication related to single implant and two-implant retained mandibular overdentures. To manage such complication, a thin metal mesh is used to reinforce the overdenture and also to make the prostheses lighter and cost effective as compared to conventional cast metal framework.

  7. International Trade: a Reinforced Urn Network Model

    CERN Document Server

    Peluso, Stefano; Muliere, Pietro; Lomi, Alessandro

    2016-01-01

    We propose a unified modelling framework that theoretically justifies the main empirical regularities characterizing the international trade network. Each country is associated to a Polya urn whose composition controls the propensity of the country to trade with other countries. The urn composition is updated through the walk of the Reinforced Urn Process of Muliere et al. (2000). The model implies a local preferential attachment scheme and a power law right tail behaviour of bilateral trade flows. Different assumptions on the urns' reinforcement parameters account for local clustering, path-shortening and sparsity. Likelihood-based estimation approaches are facilitated by feasible likelihood analytical derivation in various network settings. A simulated example and the empirical results on the international trade network are discussed.

  8. CO2-Laser Cutting Fiber Reinforced Polymers

    Science.gov (United States)

    Mueller, R.; Nuss, Rudolf; Geiger, Manfred

    1989-10-01

    Guided by experimental investigations laser cutting of glass fiber reinforced reactive injection moulded (RRIM)-polyurethanes which are used e.g. in car industry for bumpers, spoilers, and further components is described. A Comparison with other cutting techniques as there are water jet cutting, milling, punching, sawing, cutting with conventional knife and with ultrasonic excited knife is given. Parameters which mainly influence cutting results e.g. laser power, cutting speed, gas nature and pressure will be discussed. The problematic nature in characterising micro and macro geometry of laser cut edges of fiber reinforced plastic (FRP) is explained. The topography of cut edges is described and several characteristic values are introduced to specify the obtained working quality. The surface roughness of laser cut edges is measured by both, an optical and a mechanical sensor and their reliabilities are compared.

  9. Transitivity reinforcement in the coevolving voter model

    CERN Document Server

    Malik, Nishant; Lee, Hsuan-Wei; Mucha, Peter J

    2016-01-01

    One of the fundamental structural properties of many networks is triangle closure. Whereas the influence of this transitivity on a variety of contagion dynamics has been previously explored, existing models of coevolving or adaptive network systems use rewiring rules that randomize away this important property. In contrast, we study here a modified coevolving voter model dynamics that explicitly reinforces and maintains such clustering. Employing extensive numerical simulations, we establish that the transitions and dynamical states observed in coevolving voter model networks without clustering are altered by reinforcing transitivity in the model. We then use a semi-analytical framework in terms of approximate master equations to predict the dynamical behaviors of the model for a variety of parameter settings.

  10. Accelerating Reinforcement Learning through Implicit Imitation

    CERN Document Server

    Boutilier, C; 10.1613/jair.898

    2011-01-01

    Imitation can be viewed as a means of enhancing learning in multiagent environments. It augments an agent's ability to learn useful behaviors by making intelligent use of the knowledge implicit in behaviors demonstrated by cooperative teachers or other more experienced agents. We propose and study a formal model of implicit imitation that can accelerate reinforcement learning dramatically in certain cases. Roughly, by observing a mentor, a reinforcement-learning agent can extract information about its own capabilities in, and the relative value of, unvisited parts of the state space. We study two specific instantiations of this model, one in which the learning agent and the mentor have identical abilities, and one designed to deal with agents and mentors with different action sets. We illustrate the benefits of implicit imitation by integrating it with prioritized sweeping, and demonstrating improved performance and convergence through observation of single and multiple mentors. Though we make some stringent ...

  11. Processes for fabricating composite reinforced material

    Energy Technology Data Exchange (ETDEWEB)

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2015-11-24

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  12. Autonomous reinforcement learning with experience replay.

    Science.gov (United States)

    Wawrzyński, Paweł; Tanwani, Ajay Kumar

    2013-05-01

    This paper considers the issues of efficiency and autonomy that are required to make reinforcement learning suitable for real-life control tasks. A real-time reinforcement learning algorithm is presented that repeatedly adjusts the control policy with the use of previously collected samples, and autonomously estimates the appropriate step-sizes for the learning updates. The algorithm is based on the actor-critic with experience replay whose step-sizes are determined on-line by an enhanced fixed point algorithm for on-line neural network training. An experimental study with simulated octopus arm and half-cheetah demonstrates the feasibility of the proposed algorithm to solve difficult learning control problems in an autonomous way within reasonably short time. PMID:23237972

  13. Seismic evaluation of reinforced masonry walls

    International Nuclear Information System (INIS)

    Masonry walls in operating nuclear plants are in many cases found to be overstressed in terms of allowable stresses when evaluated using current seismic design criteria. However, experimental evidence exists indicating that reinforced masonry walls have a considerable margin between the load levels at which allowable stresses are exceeded and the load levels at which structural distress and loss of function occurs. This paper presents a methodology which allows the actual capacity of reinforced masonry walls under seismic loading to be quantified. The methodology is based on the use of non-linear dynamic analyses and incorporates observed hysteretic behavior for both in-plane and out-of-plane response. Experimental data is used to develop response parameters and to validate the results predicted by the models. Criteria have been concurrently developed to evaluate the deformations and material performance in the walls to ensure adequate margins of safety for the required function. An example of the application of these procedures is provided

  14. Long-short fiber reinforced thermoplastics

    Energy Technology Data Exchange (ETDEWEB)

    Gore, C.R.; Cuff, G.; Cianelli, D.A.; Travis, J.E.

    1986-01-01

    This paper presents information on a new family of fiber-reinforced thermoplastic compounds developed by ICI PLC and now produced by LNP under the trade mark ''Verton.'' Production is by a pultrusion process, rather than by the usual compounding extruder, which enables a high level of impregnation to be achieved without damaging the fibers. The result in molded parts is a 0.24-0.40 inch (6-10 mm) typical fiber length versus 0.008-0.016 inches (0.2-0.4 mm) for conventional short fiber products. Consequently, this enables fabricators to achieve typically a 10 to 20-fold increase in average fiber length in the finished component. These long-short fiber reinforced compounds exhibit substantial property improvements over short fiber system. Processing conditions are similar to corresponding short fiber compounds.

  15. Modelling Tension Stiffening in Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Christiansen, Morten Bo; Nielsen, Mogens Peter

    1997-01-01

    Part I of the present thesis deals with crack formation in reinforced concrete and the phenomenon of tension stiffening in concrete tension rods reinforced with deformed bars.Two physical models are presented for uniaxial tension, and they are modified for application on beams subjected to pure...... crack widths predicted by the models are compared with experimental data from tests on tension rods as well as flexural beams.In the light of the simple assumptions made and the random nature of cracking, the accordance between the models and the test data is quite good.Part II of the present thesis...... the light of the simple assumptions, quite good accordance is found.Part III of the thesis deals with the deformations of a beam symmetrically loaded by two concentrated forces. In the shear-flexure beam model it is assumed that the load is carried by means of a stringer system and a diagonal stress...

  16. Experimental Investigation on Reinforced Ultra-High-Performance Fiber-Reinforced Concrete Composite Beams Subjected to Combined Bending and Shear

    OpenAIRE

    Noshiravani, Talayeh; Bruehwiler, Eugen

    2013-01-01

    An experimental study on a series of composite beams combining a 250 mm (9.84 in.) deep reinforced concrete (RC) element and a 50 mm (1.97 in.) thick reinforced ultra-high-performance fiber-reinforced concrete (R-UHPFRC) element is presented. The specimens are tested in a cantilever-beam setup with the R-UHPFRC element acting as an additional tensile reinforcement. The test parameters include the span length and the ratio and type of the steel reinforcing bars, including stirrups. Most of the...

  17. Inverse Reinforcement Learning in Relational Domains

    OpenAIRE

    Munzer, Thibaut; Piot, Bilal; Geist, Matthieu; Pietquin, Olivier; Lopes, Manuel

    2015-01-01

    In this work, we introduce the first approach to the Inverse Reinforcement Learning (IRL) problem in relational domains. IRL has been used to recover a more compact representation of the expert policy leading to better generalization performances among different contexts. On the other hand, rela-tional learning allows representing problems with a varying number of objects (potentially infinite), thus provides more generalizable representations of problems and skills. We show how these differe...

  18. Polypropylene matrix composites reinforced with coconut fibers

    OpenAIRE

    Maria Virginia Gelfuso; Pedro Vieira Gurgel da Silva; Daniel Thomazini

    2011-01-01

    Polypropylene matrix composites reinforced with treated coconut fibers were produced. Fibers chemically treated (alkalization-CCUV samples) or mechanically treated (ultrasonic shockwave-CMUV samples) were dried using UV radiation. The goal was to combine low cost and eco-friendly treatments to improve fiber-matrix adhesion. Composite samples containing up to 20 vol. (%) of untreated and treated coconut fibers were taken from boxes fabricated by injection molding. Water absorption and mechanic...

  19. Seismic vulnerability of precast reinforced concrete structures

    OpenAIRE

    Kramar, Miha

    2008-01-01

    In the Ph.D. thesis, the seismic vulnerability and seismic collapse risk of precast reinforced concrete structures, typical for the building practice in Slovenia and Europe, are discussed. Full-scale pseudo- dynamic and cyclic tests of some precast structures have confirmed the assumption of the large strength of connections, and have provided important information about the behaviour of very slender cantilever columns when subjected to large deformations, as the structure approaches collapse...

  20. Error reducing sampling in reinforcement learning

    OpenAIRE

    Scherrer, Bruno; Mannor, Shie

    2004-01-01

    In reinforcement learning, an agent collects information interacting with an environment and uses it to derive a behavior. This paper focuses on efficient sampling; that is, the problem of choosing the interaction samples so that the corresponding behavior tends quickly to the optimal behavior. Our main result is a sensitivity analysis relating the choice of sampling any state-action pair to the decrease of an error bound on the optimal solution. We derive two new model-based algorithms. Simu...

  1. Dual Control for Approximate Bayesian Reinforcement Learning

    OpenAIRE

    Klenske, Edgar D.; Hennig, Philipp

    2015-01-01

    Control of non-episodic, finite-horizon dynamical systems with uncertain dynamics poses a tough and elementary case of the exploration-exploitation trade-off. Bayesian reinforcement learning, reasoning about the effect of actions and future observations, offers a principled solution, but is intractable. We review, then extend an old approximate approach from control theory---where the problem is known as dual control---in the context of modern regression methods, specifically generalized line...

  2. Early Loaded Single Implant Reinforced Mandibular Overdenture

    OpenAIRE

    Nischal, K; Chowdhary, R.

    2016-01-01

    Rehabilitating atrophied mandible with two-implant supported denture is a common treatment modality for implant retained removable overdenture in mandible. This paper aims to design a treatment modality where single implant reinforced overdenture is fabricated for a severely atrophied mandibular ridge with early loading protocol. Results of studies have shown that a single implant mandibular overdenture significantly increases the satisfaction and quality of life of patients with edentulism. ...

  3. Analysis of composite car bumper reinforcement

    OpenAIRE

    Kleisner V.; Zemčík R.

    2009-01-01

    The presented work summarizes the present state of car passive safety testing according to European methodologies. The main objective is to analysis a bumper reinforcement made of composite materials. The bumper is tested according to RCAR (Research Council for Automobile Repairs) methodology using numerical simulation. Individual proposed variants are compared with the existing steel construction which does not comply with manufacturers specifications. The PAM-Crash software is used for the ...

  4. Continuous Wire Reinforcement for Jammed Granular Architecture

    OpenAIRE

    Fauconneau, Matthias; Wittel, Falk K.; Herrmann, Hans J.

    2015-01-01

    The mechanical behavior of continuous fiber reinforced granular columns is simulated by means of a Discrete Element Model. Spherical particles are randomly deposited simultaneously with a wire, that is deployed following different patterns inside of a flexible cylinder for triaxial compression testing. We quantify the effect of three different fiber deployment patterns on the failure envelope, represented by Mohr-Coulomb cones, and derive suggestions for improved deployment strategies.

  5. Reinforcement Learning for a New Piano Mover

    OpenAIRE

    Yuko Ishiwaka; Tomohiro Yoshida; Yukinori Kakazu

    2005-01-01

    We attempt to achieve corporative behavior of autonomous decentralized agents constructed via Q-Learning, which is a type of reinforcement learning. As such, in the present paper, we examine the piano mover's problem. We propose a multi-agent architecture that has a training agent, learning agents and intermediate agent. Learning agents are heterogeneous and can communicate with each other. The movement of an object with three kinds of agent depends on the composition of the actions of the le...

  6. Reinforced concrete behavior due to missile impact

    International Nuclear Information System (INIS)

    The assessment of the safety of nuclear reactors has necessitated the study of the effect of missiles on reinforced concrete containment structures. Two simple theoretical calculational methods have been developed to provide basic information. The first is based on a crude energy balance approach in which that part of the kinetic energy of the missile which is transferred into the containment structure, is absorbed only as bending strain energy. To determine the energy transferred into the structure it is assumed that during the loading the target does not respond. The energy input to the structure is thus equal to the kinetic energy it will possess immediately the impulse has been removed. The boundary of the responding zone is defined by the distance travelled by the shear stress wave during the time in which the impact force increases to the load at which the shear capacity reaches the ultimate shear resistance. The second method is based on the equation of motion for an equivalent one-degree-of-freedom system assuming that only the peak value of deflection is important and that damping can be ignored. The spring stiffness of the equivalent system has been based upon the stiffness of the actual disc configuration responding in the flexural mode only. The boundaries of the disc have been defined by using the elastic plate formulae and equating those positive and negative moments which will produce a specified yield line pattern which may be inferred from plastic plate formulae. The equation of motion is solved to indicate how the quantity of reinforcement included in the structure may modify the peak deflection. By limiting the ductility ratio of the reinforcement to some prescribed level it is possible to indicate the quantity of reinforcement w

  7. Vicarious reinforcement: Expected and unexpected effects

    OpenAIRE

    Ollendick, Thomas H.; Dailey, Donna; Shapiro, Edward S.

    1983-01-01

    The primary purpose of this study was to examine the effects on one child of observing another child receive direct social reinforcement. In the first part of the study, pairs of same-sex children worked on puzzles for three sessions spaced 2 to 3 days apart. One child was praised on a continuous schedule for performance, whereas the other received no praise. Although children who observed other children being praised increased their performance initially (as predicted by vicarious reinforcem...

  8. Deep Reinforcement Learning in Parameterized Action Space

    OpenAIRE

    Hausknecht, Matthew; Stone, Peter

    2015-01-01

    Recent work has shown that deep neural networks are capable of approximating both value functions and policies in reinforcement learning domains featuring continuous state and action spaces. However, to the best of our knowledge no previous work has succeeded at using deep neural networks in structured (parameterized) continuous action spaces. To fill this gap, this paper focuses on learning within the domain of simulated RoboCup soccer, which features a small set of discrete action types, ea...

  9. Optimal Reinforcement Learning for Gaussian Systems

    OpenAIRE

    Hennig, Philipp

    2011-01-01

    The exploration-exploitation trade-off is among the central challenges of reinforcement learning. The optimal Bayesian solution is intractable in general. This paper studies to what extent analytic statements about optimal learning are possible if all beliefs are Gaussian processes. A first order approximation of learning of both loss and dynamics, for nonlinear, time-varying systems in continuous time and space, subject to a relatively weak restriction on the dynamics, is described by an inf...

  10. Efficient Reinforcement Learning using Gaussian Processes

    OpenAIRE

    Deisenroth, Marc Peter

    2010-01-01

    This book examines Gaussian processes in both model-based reinforcement learning (RL) and inference in nonlinear dynamic systems. First, we introduce PILCO, a fully Bayesian approach for efficient RL in continuous-valued state and action spaces when no expert knowledge is available. PILCO takes model uncertainties consistently into account during long-term planning to reduce model bias. Second, we propose principled algorithms for robust filtering and smoothing in GP dynamic systems.

  11. Benchmarking Deep Reinforcement Learning for Continuous Control

    OpenAIRE

    Duan, Yan; Chen, Xi; Houthooft, Rein; Schulman, John; Abbeel, Pieter

    2016-01-01

    Recently, researchers have made significant progress combining the advances in deep learning for learning feature representations with reinforcement learning. Some notable examples include training agents to play Atari games based on raw pixel data and to acquire advanced manipulation skills using raw sensory inputs. However, it has been difficult to quantify progress in the domain of continuous control due to the lack of a commonly adopted benchmark. In this work, we present a benchmark suit...

  12. Reinforcement Learning in Continuous Action Spaces

    OpenAIRE

    Hasselt, H. van; Wiering, M.A.

    2007-01-01

    Quite some research has been done on Reinforcement Learning in continuous environments, but the research on problems where the actions can also be chosen from a continuous space is much more limited. We present a new class of algorithms named Continuous Actor Critic Learning Automaton (CACLA) that can handle continuous states and actions. The resulting algorithm is straightforward to implement. An experimental comparison is made between this algorithm and other algorithms that can handle cont...

  13. Smart Textile Reinforced Concrete Sensory Structures

    OpenAIRE

    Goldfeld, Yiska; Rabinovitch, Oded; Quadflieg, Till; Fishbain, Barak; Gries, Thomas

    2014-01-01

    International audience This study examines and demonstrates the feasibility of a new class of smart textile reinforced concrete (TRC) structural elements with inherent sensing capabilities that are based on embedding metallic yarns in the textile mesh. The new approach combines the advantages of thin walled glass fiber based TRC with the electro-mechanical properties of the stainless steel fibers embedded in the textile matrix. To examine this concept and to demonstrate its potential feasi...

  14. Action Selection methods using Reinforcement Learning

    OpenAIRE

    Humphrys, Mark

    1996-01-01

    Action Selection schemes, when translated into precise algorithms, typically involve considerable design effort and tuning of parameters. Little work has been done on solving the problem using learning. This paper compares eight different methods of solving the action selection problem using Reinforcement Learning (learning from rewards). The methods range from centralised and cooperative to decentralised and selfish. They are tested in an artificial world and their performance, memory requir...

  15. Novel apparatus and method for drug reinforcement.

    Science.gov (United States)

    Feduccia, Allison A; Duvauchelle, Christine L

    2010-01-01

    Animal models of reinforcement have proven to be useful for understanding the neurobiological mechanisms underlying drug addiction. Operant drug self-administration and conditioned place preference (CPP) procedures are expansively used in animal research to model various components of drug reinforcement, consumption, and addiction in humans. For this study, we used a novel approach to studying drug reinforcement in rats by combining traditional CPP and self-administration methodologies. We assembled an apparatus using two Med Associate operant chambers, sensory stimuli, and a Plexiglas-constructed neutral zone. These modifications allowed our experiments to encompass motivational aspects of drug intake through self-administration and drug-free assessment of drug/cue conditioning strength with the CPP test. In our experiments, rats self-administered cocaine (0.75 mg/kg/inj, i.v.) during either four (e.g., the "short-term") or eight (e.g., the "long-term") alternating-day sessions in an operant environment containing distinctive sensory cues (e.g., olfactory and visual). On the alternate days, in the other (differently-cued) operant environment, saline was available for self-infusion (0.1 ml, i.v.). Twenty-four hours after the last self-administration/cue-pairing session, a CPP test was conducted. Consistent with typical CPP findings, there was a significant preference for the chamber associated with cocaine self-administration. In addition, in animals undergoing the long-term experiment, a significant positive correlation between CPP magnitude and the number of cocaine-reinforced lever responses. In conclusion, this apparatus and approach is time and cost effective, can be used to examine a wide array of topics pertaining to drug abuse, and provides more flexibility in experimental design than CPP or self-administration methods alone. PMID:20811325

  16. Developing innovative systems for reinforced masonry walls

    OpenAIRE

    Mosele, F.; Porto, F. da; Modena, C.; Fusco, A. di; Cesare, G. di; Vasconcelos, Graça; Haach, V.; Lourenço, Paulo B.; Beer, I; Schmidt, U.; Brameshuber, W.; Scheufler, W.; Schermer, D. C.; Zilch, K.

    2006-01-01

    The Commission of the European Communities has recently funded a CRAFT research project aimed at developing innovative systems for load and non-load-bearing reinforced masonry walls. The project involves twelve partners coming from four different European countries, among which there are universities and research centres, small and medium enterprises for the production of clay and concrete units and mortars, a company for advanced metal products and industrial associations of brick and block ...

  17. Adaptive Educational Software by Applying Reinforcement Learning

    OpenAIRE

    Abdellah BENNANE

    2013-01-01

    The introduction of the intelligence in teaching software is the object of this paper. In software elaboration process, one uses some learning techniques in order to adapt the teaching software to characteristics of student. Generally, one uses the artificial intelligence techniques like reinforcement learning, Bayesian network in order to adapt the system to the environment internal and external conditions, and allow this system to interact efficiently with its potentials user. The intention...

  18. Commingling Yarns for Reinforcement of Concrete

    OpenAIRE

    Kravaev, Plamen; Janetzko, Steffen; Gries, Thomas; Kang, Bong-Gu; Brameshuber, Wolfgang; Zell, Maike; Hegger, Josef

    2009-01-01

    Textile reinforced concrete (TRC) is an innovative composite material, which is being intensely and practice-oriented investigated on national and international level. In the last few years this material has gained increasing importance in the field of civil engineering. In the context of the collaborative research project SFB 532 at the RWTH Aachen University, research was carried out to understand and to predict the behaviour of different yarn structures in fine grained concrete. Based on t...

  19. Hierarchical reinforcement learning for communicating agents

    OpenAIRE

    Rovatsos, Michael; Fischer, Felix; Weiss, Gerhard

    2004-01-01

    This paper proposes hierarchical reinforcement learning (RL) methods for communication in multiagent coordination problems modelled as Markov Decision Processes (MDPs). To bridge the gap between the MDP view and the methods used to specify communication protocols in multiagent systems (using logical conditions and propositional message structure), we utilise interaction frames as powerful policy abstractions that can be combined with case-based reasoning techniques. Also, we exploit the fact ...

  20. Thermal cracking in reinforced concrete containment structures

    International Nuclear Information System (INIS)

    The distribution and width of cracks in the reinforced concrete wall of a cylindrical container are examined, to evaluate the potential air leakage under a given pressure gradient. The containers are internally uniformally heated. The structures considered are: cylinders free from internal structures; cylinders with internal slab perpendicular to the axis; cylinders with radial beam-wall, and same structures where the ovalization of the wall is opposed by a circular slab. The first two cases have been analyzed experimentally, by means of a series of models of 1.5m diameter, 5cm thickness, with increasing horizontal reinforcing, and numerically by a finite element technique in axisymmetry. An incremental nonlinear analysis is utilized with a commercially available computer code. The other two cases have been analyzed only numerically in a linear range. Up to now some rheological aspects are not clearly understood. Nevertheless some practical results seem to deserve attention. They are the following: the crack distribution in the first type model are in good agreement with the flexural cracks theory; on extension of such a theory is proposed for the second type model; when the crack width recommended by ACI Committee 207 for massive structures is accounted for, the required circumferential reinforcement is nearly 0.35%. This is an agreement with the recommandations of the ACI Committee 334 'Concrete Shells'; a state of tension all along the thickness of the wall results in models of the fourth type and a single crack may develop in such a case if the circumferential reinforcing is of the order as above

  1. Conditioned reinforcement: Experimental and theoretical issues

    OpenAIRE

    Williams, Ben A.

    1994-01-01

    The concept of conditioned reinforcement has received decreased attention in learning textbooks over the past decade, in part because of criticisms of its validity by major behavior theorists and in part because its explanatory function in a variety of different conditioning procedures has become uncertain. Critical data from the major procedures that have been used to investigate the concept (second-order schedules, chain schedules, concurrent chains, observing responses, delay-of-reinforcem...

  2. Reinforcement, repeated games, and local interaction

    OpenAIRE

    Kirchkamp, Oliver; Nagel, Rosemarie

    2002-01-01

    We investigate and compare different approaches to derive strategies from laboratory data in prisoners' dilemmas experiments. While theory suggests more cooperation in spatial structures than in spaceless ones, we find in our experiments either the opposite or no difference. In this paper we investigate to which degree learning and reinforcement explains this dependence on structure and information. Starting from a very simple model we gradually develop a setup where players use repeated game...

  3. Attainability of Boundary Points under Reinforcement Learning

    OpenAIRE

    Ed Hopkins; Martin Posch

    2003-01-01

    This paper investigates the properties of the most common form of reinforcement learning (the "basic model" of Erev and Roth, American Economic Review, 88, 848-881, 1998). Stochastic approximation theory has been used to analyse the local stability of fixed points under this learning process. However, as we show, when such points are on the boundary of the state space, for example, pure strategy equilibria, standard results from the theory of stochastic approximation do not apply. We offer wh...

  4. Design and analysis of reinforced fiber composites

    CERN Document Server

    Yamagata, Nobuki

    2016-01-01

    The papers in this volume present a broad range of applications for reinforced fiber composites - from thin shell structures to tires. Linear and nonlinear structural behavior (from linear buckling to nonlinear yelding and fracture) are discussed as well as different materials are presented. Latest developments in computational methods for constructíons are presented which will help to save money and time. This is an edited collection of papers presented at a symposium at the WCCM, Barcelona, 2014.

  5. Mix design of steel fiber reinforced concrete

    OpenAIRE

    Moreno, E.; Fernández Cánovas, M.

    1997-01-01

    Mix design of steel fiber reinforced concrete (SFRC) is concerned with achieving a workability, homogeneity, durability and strength suitable for its use. Variables defining any mix design of SFRC are commented below, as well as their influence on some properties of fresh and hardened SFRC. A special attention is paid to concrete, since it's the main use of steel fibers in Spain now, followed by paving construction.

    El objetivo de una correcta dosificación de horm...

  6. Advanced thermoplastic carbon fibre reinforced pultruded composites

    OpenAIRE

    Novo, P. J.; Silva, J F; Nunes, J. P.; MARQUES, A. T.

    2014-01-01

    The aim of this work is to optimize the production of new continuous carbon fibers reinforced thermoplastic matrix pre-impregnated materials (towpregs) continuously processed by dry deposition of polymer powders in a new equipment developed by the Institute for Polymers and Composites (IPC). The processing of the produced towpregs by pultrusion, in a developed prototype equipment existing in the Engineering School of the Polytechnic Institute of Porto (ISEP), was also optimized. Two differ...

  7. Exhaust System Reinforced by Jet Flow

    OpenAIRE

    Pedersen, Lars Germann; Nielsen, Peter V

    1991-01-01

    Since 1985 the University of Aalborg and Nordfab A/S have been working on an exhaust principle which is quite different from traditional exhaust systems. The REEXS principle (Reinforced Exhaust System), which originally was designed for the agricultural sector, is particularly well-suited for industrial ventilation purposes. With the REEXS principle it is possible to create a flow pattern in front of the exhaust opening which will have a considerable influence on the general flow in a given r...

  8. Stainless steel for reinforcing bar concrete

    International Nuclear Information System (INIS)

    Where corrosion resisting reinforcing bar is required, stainless steel has been employed for many applications. The longest recorded use so far is over 75 years for a restoration project in the United Kingdom. Other areas are highway bridge decks, retaining walls, tunnels, pier and overpass structures all of which use stainless steel to prevent corrosion and extend structure life. Carbon steel rebar leads to premature failure via concrete spalling that results in excessive repair, high cost, traffic delay and commerce disruption. Selection of stainless steel is based on its corrosion resistance, strength and long life. Installed cost using stainless steel reinforcing barranges from one to fifteen percent depending on structure complexity. Life Cycle Cost calculations reveal when stainless steel reinforcing bar is factored into the design, with a life expectancy up to 125 years, the alloy is cost effective. Data will be exhibited relative to mechanical and physical properties of stainless steel compared to carbon steel rebar. Some stainless rebar applications around the World will be discussed in addition to laboratory and field test results with U-bent stainless steel specimens embedded in concrete. Comments will also be made relative to the environment, lengthened journeys, delivery delay, fuel burned as vehicles sit at idle, drilling, blasting, crushing and transport of aggregate, cement and the attendant power units to manufacture these items for reconstruction. (author)

  9. Glass Fiber Reinforced Concrete & Its Properties

    Directory of Open Access Journals (Sweden)

    Shrikant Harle

    2014-01-01

    Full Text Available Glass fiber reinforced concrete (GFRC is a recent introduction in the field of civil engineering. So, it has been extensively used in many countries since its introduction two decades ago. This product has advantage of being light weight and thereby reducing the overall cost of construction, ultimately bringing economy in construction. Steel reinforcement corrosion and structural deterioration in reinforced concrete structures are common and prompted many researchers to seek alternative materials and rehabilitation techniques. So, researchers all over the world are attempting to develop high performance concrete using glass fibers and other admixtures in the concrete up to certain extent. In the view of global sustainable scenario, it is imperative that fibers like glass, carbon, aramid and poly-propylene provide very wide improvements in tensile strength, fatigue characteristics, durability, shrinkage characteristics, impact, cavitations, erosion resistance and serviceability of concrete. The present work is only an accumulation of information about GFRC and the research work which is already carried out by other researchers.

  10. Vibrations of carbon nanotube-reinforced composites

    Science.gov (United States)

    Formica, Giovanni; Lacarbonara, Walter; Alessi, Roberto

    2010-05-01

    This work deals with a study of the vibrational properties of carbon nanotube-reinforced composites by employing an equivalent continuum model based on the Eshelby-Mori-Tanaka approach. The theory allows the calculation of the effective constitutive law of the elastic isotropic medium (matrix) with dispersed elastic inhomogeneities (carbon nanotubes). The devised computational approach is shown to yield predictions in good agreement with the experimentally obtained elastic moduli of composites reinforced with uniformly aligned single-walled carbon nanotubes (CNTs). The primary contribution of the present work deals with the global elastic modal properties of nano-structured composite plates. The investigated composite plates are made of a purely isotropic elastic hosting matrix of three different types (epoxy, rubber, and concrete) with embedded single-walled CNTs. The computations are carried out via a finite element (FE) discretization of the composite plates. The effects of the CNT alignment and volume fraction are studied in depth to assess how the modal properties are influenced both globally and locally. As a major outcome, the lowest natural frequencies of CNT-reinforced rubber composites are shown to increase up to 500 percent.

  11. Fiber reinforced polymer composites for bridge structures

    Directory of Open Access Journals (Sweden)

    Alexandra CANTORIU

    2013-12-01

    Full Text Available Rapid advances in construction materials technology have led to the emergence of new materials with special properties, aiming at safety, economy and functionality of bridges structures. A class of structural materials which was originally developed many years ago, but recently caught the attention of engineers involved in the construction of bridges is fiber reinforced polymer composites. This paper provides an overview of fiber reinforced polymer composites used in bridge structures including types, properties, applications and future trends. The results of this study have revealed that this class of materials presents outstanding properties such as high specific strength, high fatigue and environmental resistance, lightweight, stiffness, magnetic transparency, highly cost-effective, and quick assembly, but in the same time high initial costs, lack of data on long-term field performance, low fire resistance. Fiber reinforced polymer composites were widely used in construction of different bridge structures such as: deck and tower, I-beams, tendons, cable stands and proved to be materials for future in this field.

  12. Natural fiber-reinforced polymer composites

    International Nuclear Information System (INIS)

    Natural fibers have been used to reinforce materials for over 3,000 years. More recently they have been employed in combination with plastics. Many types of natural fi fibers have been investigated for use in plastics including Flax, hemp, jute, straw, wood fiber, rice husks, wheat, barley, oats, rye, cane (sugar and bamboo), grass reeds, kenaf, ramie, oil palm empty fruit bunch, sisal, coir, water hyacinth, pennywort, kapok, paper-mulberry, raphia, banana fiber, pineapple leaf fiber and papyrus. Natural fibers have the advantage that they are renewable resources and have marketing appeal. The Asian markets have been using natural fibers for many years e.g., jute is a common reinforcement in India. Natural fibers are increasingly used in automotive and packaging materials. Pakistan is an agricultural country and it is the main stay of Pakistan's economy. Thousands of tons of different crops are produced but most of their wastes do not have any useful utilization. Agricultural wastes include wheat husk, rice husk, and their straw, hemp fiber and shells of various dry fruits. These agricultural wastes can be used to prepare fiber reinforced polymer composites for commercial use. This report examines the different types of fibers available and the current status of research. Many references to the latest work on properties, processing and application have been cited in this review. (author)

  13. Contrafreeloading, reinforcement rate, and behavioral momentum.

    Science.gov (United States)

    Podlesnik, Christopher A; Jimenez-Gomez, Corina

    2016-07-01

    Contrafreeloading involves organisms working for food when an identical source of food is freely available. The present study assessed whether training reinforcement rates influenced contrafreeloading by arranging a within-subject and within-session design using pigeons. Across different alternating discriminative stimuli, variable-interval schedules arranged leaner (30 per hour) and richer (120 per hour) rates of food reinforcement. Responding decreased but persisted in the presence of free food during the session (i.e., contrafreeloading). Further, responding tended to be similar between components initially but greater persistence emerged in the richer component with additional exposure. With pre-session feeding, responding did not change systematically across test sessions and tended to be more persistent in the richer component. Greater persistence with greater training reinforcement rates is generally consistent with an influential theory of response persistence, behavioral momentum theory. However, the different patterns of responding across test sessions between pre- and within-session feeding reveals multiple behavioral processes involved in contrafreeloading that have yet to be fully understood. Behavioral momentum theory could provide a useful theoretical framework for understanding and quantifying the behavioral processes underlying contrafreeloading. PMID:27045696

  14. Reinforcement of osteosynthesis screws with brushite cement.

    Science.gov (United States)

    Van Landuyt, P; Peter, B; Beluze, L; Lemaître, J

    1999-08-01

    The fixation of osteosynthesis screws remains a severe problem for fracture repair among osteoporotic patients. Polymethyl-methacrylate (PMMA) is routinely used to improve screw fixation, but this material has well-known drawbacks such as monomer toxicity, exothermic polymerization, and nonresorbability. Calcium phosphate cements have been developed for several years. Among these new bone substitution materials, brushite cements have the advantage of being injectable and resorbable. The aim of this study is to assess the reinforcement of osteosynthesis screws with brushite cement. Polyurethane foams, whose density is close to that of cancellous bone, were used as bone model. A hole was tapped in a foam sample, then brushite cement was injected. Trabecular osteosynthesis screws were inserted. After 24 h of aging in water, the stripping force was measured by a pull-out test. Screws (4.0 and 6.5 mm diameter) and two foam densities (0.14 and 0.28 g/cm3) were compared. Cements with varying solid/liquid ratios and xanthan contents were used in order to obtain the best screw reinforcement. During the pull-out test, the stripping force first increases to a maximum, then drops to a steady-state value until complete screw extraction. Both maximum force and plateau value increase drastically in the presence of cement. The highest stripping force is observed for 6.5-mm screws reinforced with cement in low-density foams. In this case, the stripping force is multiplied by 3.3 in the presence of cement. In a second experiment, cements with solid/liquid ratio ranging from 2.0 to 3.5 g/mL were used with 6.5-mm diameter screws. In some compositions, xanthan was added to improve injectability. The best results were obtained with 2.5 g/mL cement containing xanthan and with 3.0 g/mL cements without xanthan. A 0.9-kN maximal stripping force was observed with nonreinforced screws, while 1.9 kN was reached with reinforced screws. These first results are very promising regarding screw

  15. Edge-reinforced random walk, Vertex-Reinforced Jump Process and the supersymmetric hyperbolic sigma model

    CERN Document Server

    Sabot, Christophe

    2011-01-01

    Edge-reinforced random walk (ERRW), introduced by Coppersmith and Diaconis in 1986, is a random process that takes values in the vertex set of a graph G, which is more likely to cross edges it has visited before. We show that it can be interpreted as an annealed version of the Vertex-reinforced jump process (VRJP), conceived by Werner and first studied by Davis and Volkov (2002,2004), a continuous-time process favouring sites with more local time. We calculate, for any finite graph G, the limiting measure of the centred occupation time measure of VRJP, and interpret it as a supersymmetric hyperbolic sigma model in quantum field theory. This enables us to deduce that VRJP is recurrent in any dimension for large reinforcement, using a localisation result of Disertori and Spencer (2010).

  16. Flexural strengthening of Reinforced Concrete (RC Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP Laminates

    Directory of Open Access Journals (Sweden)

    Aravind N.

    2015-01-01

    Full Text Available Strengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP sheets for strengthening Reinforced Concrete (RC beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

  17. Flexural retrofitting of reinforced concrete structures using Green Natural Fiber Reinforced Polymer plates

    Science.gov (United States)

    Cervantes, Ignacio

    An experimental study will be carried out to determine the suitability of Green Natural Fiber Reinforced Polymer plates (GNFRP) manufactured with hemp fibers, with the purpose of using them as structural materials for the flexural strengthening of reinforced concrete (RC) beams. Four identical RC beams, 96 inches long, are tested for the investigation, three control beams and one test beam. The first three beams are used as references; one unreinforced, one with one layer of Carbon Fiber Reinforced Polymer (CFRP), one with two layers of CFRP, and one with n layers of the proposed, environmental-friendly, GNFRP plates. The goal is to determine the number of GNFRP layers needed to match the strength reached with one layer of CFRP and once matched, assess if the system is less expensive than CFRP strengthening, if this is the case, this strengthening system could be an alternative to the currently used, expensive CFRP systems.

  18. Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

    Science.gov (United States)

    Aravind, N.; Samanta, Amiya K.; Roy, Dilip Kr. Singha; Thanikal, Joseph V.

    2015-01-01

    Strengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

  19. Long term behavior of self-compacting reinforced concrete beams

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-jie; YU Zhi-wu; JIANG Li-zhong

    2008-01-01

    Tests were carded out on 8 self-compacting reinforced concrete(SCC) beams and 4 normal reinforced concrete beams. The effects of mode of consolidation, load level, reinforcing ratio and structural type on long term behavior of SCC were investigated. Under the same environmental conditions, the shrinkage-time curve of self-compacting concrete beam is very similar to that of normal concrete beam. For both self-compacting reinforced concrete beams and normal reinforced concrete beams, the rate of shrinkage at early stages is higher, the shrinkage strain at 2 months is about 60% of the maximum value at one year. The shrinkage strain of self-compacting reinforced concrete beam after one year is about 450×10-6. Creep deflection of self-compacting reinforced concrete beam decreases as the tensile reinforcing ratio increases. The deflection creep coefficient of self-compacting reinforced concrete beam after one and a half year is about 1.6, which is very close to that of normal reinforced concrete beams cast with vibration. Extra cautions considering shrinkage and creep behavior are not needed for the use of SCC in engineering practices.

  20. The effects of fixed versus escalating reinforcement schedules on smoking abstinence.

    Science.gov (United States)

    Romanowich, Paul; Lamb, R J

    2015-01-01

    Studies indicate that when abstinence is initiated, escalating reinforcement schedules maintain continuous abstinence longer than fixed reinforcement schedules. However, these studies were conducted for shorter durations than most clinical trials and also resulted in larger reinforcer value for escalating participants during the 1st week of the experiment. We tested whether escalating reinforcement schedules maintained abstinence longer than fixed reinforcement schedules in a 12-week clinical trial. Smokers (146) were randomized to an escalating reinforcement schedule, a fixed reinforcement schedule, or a control condition. Escalating reinforcement participants received $5.00 for their first breath carbon monoxide (CO) sample reinforcement participants received $19.75 for each breath CO sample reinforcement participants met the breath CO criterion at least once. Escalating reinforcement participants maintained criterion breath CO levels longer than fixed reinforcement and control participants. Similar to previous short-term studies, escalating reinforcement schedules maintained longer durations of abstinence than fixed reinforcement schedules during a clinical trial. PMID:25640764

  1. Experimental study on fire protection methods of reinforced concrete beams strengthened with carbon fiber reinforced polymer

    Institute of Scientific and Technical Information of China (English)

    HU Kexu; HE Guisheng; LU Fan

    2007-01-01

    In this paper,two reinforced concrete (RC) beams strengthened with carbon fiber reinforced polymer (CFRP)and attached with thick-painted fire resistant coating were tested for fire resistance following the standard fire testing procedures.The experimental results show that the specimen pasted with the insulated layer of 50 mm in thickness could resist fire for 2.5 h.It is also demonstrated that the steel wire mesh embedded in the insulated layer can effectively prevent it from cracking and eroding under firing.

  2. Effects Of Reinforcement History On Response Rate And Response Pattern In Periodic Reinforcement

    OpenAIRE

    López, Florente; Menez, Marina

    2005-01-01

    Several researchers have suggested that conditioning history may have long-term effects on fixed-interval performances of rats. To test this idea and to identify possible factors involved in temporal control development, groups of rats initially were exposed to different reinforcement schedules: continuous, fixed-time, and random-interval. Afterwards, half of the rats in each group were studied on a fixed-interval 30-s schedule of reinforcement and the other half on a fixed-interval 90-s sche...

  3. The effect of MDMA on sensitivity to reinforcement rate.

    Science.gov (United States)

    Lie, Celia; Macaskill, Anne C; Harper, David N

    2016-04-01

    Administration of (±)3,4-methylenedioxymethamphetamine (MDMA) causes memory errors by increasing proactive interference. This might occur because MDMA alters sensitivity to reinforcement. The current 2 experiments investigated this directly by assessing the acute (Experiment 1) and chronic (Experiment 2) effects of MDMA on sensitivity to reinforcement. We presented 5 pairs of concurrent variable interval schedules within each session and calculated sensitivity to reinforcement for 3 acute doses of MDMA. In contrast to the related drug, d-amphetamine, and in spite of producing reductions in response rate, MDMA did not reduce sensitivity to reinforcement rate. Chronic administration of a fixed dose of MDMA following each session reduced response rate but did not affect sensitivity to reinforcement rate. In combination with previous research, these results indicate that related drugs may have different effects on sensitivity to reinforcement and that these effects should be considered when interpreting disruptions to operant task performance caused by drug administration. (PsycINFO Database Record PMID:26820588

  4. THEORETICAL ESTIMATION OF FIBER DISTRIBUTION IN FIBER REINFORCED CONCRETES

    Directory of Open Access Journals (Sweden)

    A. N. Tkachenko

    2011-07-01

    Full Text Available Problem statement. Theory of fiber reinforcement of concrete materials calls for the construction of appropriate mathematical models. The article describes the mathematical basis for calculating the density of intersections of reinforcing fibers in cross section of fiber concrete element as well as average cross sectional area of fibers.Results and conclusions. The problems of geometric probability are taken as the basis for con-struction of the model of reinforcing fiber distribution in concrete. The function of density of rein-forcing fiber distribution and formula for determining reinforcing fiber concentration in concrete are obtained. The functions and formulas obtained are valid for different geometrical characteris-tics of reinforcing fibers.The results obtained are presented in such form for the first time. At present, work on mathemati-cal planning of the experiment which will enable us to check the correctness of obtained theoreti-cal conclusions is underway.

  5. Reinforcement learning for microgrid energy management

    International Nuclear Information System (INIS)

    We consider a microgrid for energy distribution, with a local consumer, a renewable generator (wind turbine) and a storage facility (battery), connected to the external grid via a transformer. We propose a 2 steps-ahead reinforcement learning algorithm to plan the battery scheduling, which plays a key role in the achievement of the consumer goals. The underlying framework is one of multi-criteria decision-making by an individual consumer who has the goals of increasing the utilization rate of the battery during high electricity demand (so as to decrease the electricity purchase from the external grid) and increasing the utilization rate of the wind turbine for local use (so as to increase the consumer independence from the external grid). Predictions of available wind power feed the reinforcement learning algorithm for selecting the optimal battery scheduling actions. The embedded learning mechanism allows to enhance the consumer knowledge about the optimal actions for battery scheduling under different time-dependent environmental conditions. The developed framework gives the capability to intelligent consumers to learn the stochastic environment and make use of the experience to select optimal energy management actions. - Highlights: • A consumer exploits a 2 steps-ahead reinforcement learning for battery scheduling. • The Q-learning based mechanism is fed by the predictions of available wind power. • Wind speed state evolutions are modeled with a Markov chain model. • Optimal scheduling actions are learned through the occurrence of similar scenarios. • The consumer manifests a continuous enhance of his knowledge about optimal actions

  6. On site monitoring of concrete reinforcement corrosion

    International Nuclear Information System (INIS)

    Reinforcement corrosion is the result of the penetration through the concrete cover of the carbon dioxide (carbonation) and of chlorides. It is not a usual event in nuclear plants due to the relatively short service life required. However, in waste storage facilities with much longer target service life.. it may be one of the most relevant deterioration processes. Therefore. its detection and measurement should be one of the aspects to be taken into account in the overall management of these kind of installations. In present paper, the most usual electrochemical techniques to measure reinforcement corrosion are described. The aims of the application of these techniques is. 1) to control the performance of new constructions (embedded sensors). 2) to detect corroding areas in existing structures (by on-site measurements or by installing external sensors) and implement these values in models to recalculate the structural performance and 3) to control the efficiency of repair techniques. In the paper is as well presented the evolution from 1995 of corrosion parameters (corrosion rate, corrosion potential, electrical resistivity, concrete strains, oxygen availability) obtained in a pilot container buried in real conditions in the repository of El-Carbril-Spain. The results indicate that the temperature is the most relevant variable influencing the measurements. In conclusion: Corrosion of reinforcement can be approximately model and accurately measured on-site. The periodical corrosion rate measurements on its monitoring seems very necessary to assess present conditions of concrete structures and is a very useful tool in the case of cooling towers of power plants. Techniques based in the measurement of Polarization Resistance have been implemented in portable corrosion rate meters to obtain corrosion rate values, and corrosion-data-loggers are now operative in different structures to monitor corrosion related parameters. (authors)

  7. Hybrid fiber and nanopowder reinforced composites for wind turbine blades

    OpenAIRE

    Nikoloz M. Chikhradze; Marquis, Fernand D.S.; Guram S. Abashidze

    2015-01-01

    The results of an investigation into the production of wind turbine blades manufactured using polymer composites reinforced by hybrid (carbon, basalt, glass) fibers and strengthened by various nanopowders (oxides, carbides, borides) are presented. The hybrid fiber-reinforced composites (HFRC) were manufactured with prepreg technology by molding pre-saturated epoxy-strengthened matrix-reinforced fabric. Performance of the manufactured composites was estimated with values of the coefficient of ...

  8. Elevated temperature material properties of stainless steel reinforcing

    OpenAIRE

    Gardner, L.; Bu, Y; Francis, P; Baddoo, NR; Cashell, K; McCann, F

    2016-01-01

    Corrosion of carbon steel reinforcing bar can lead to deterioration of concrete structures, especially in regions where road salt is heavily used or in areas close to sea water. Although stainless steel reinforcing bar costs more than carbon steel, its selective use for high risk elements is cost-effective when the whole life costs of the structure are taken into account. Considerations for specifying stainless steel reinforcing bars and a review of applications are presented herein. Atten...

  9. Behavioral and neural properties of social reinforcement learning

    OpenAIRE

    Jones, Rebecca M.; Somerville, Leah H.; Li, Jian; Ruberry, Erika J.; Libby, Victoria; Glover, Gary; Henning U. Voss; Ballon, Douglas J.; Casey, BJ

    2011-01-01

    Social learning is critical for engaging in complex interactions with other individuals. Learning from positive social exchanges, such as acceptance from peers, may be similar to basic reinforcement learning. We formally test this hypothesis by developing a novel paradigm that is based upon work in non-human primates and human imaging studies of reinforcement learning. The probability of receiving positive social reinforcement from three distinct peers was parametrically manipulated while bra...

  10. Multi-Agent Reinforcement Learning Algorithm Based on Action Prediction

    Institute of Scientific and Technical Information of China (English)

    TONG Liang; LU Ji-lian

    2006-01-01

    Multi-agent reinforcement learning algorithms are studied. A prediction-based multi-agent reinforcement learning algorithm is presented for multi-robot cooperation task. The multi-robot cooperation experiment based on multi-agent inverted pendulum is made to test the efficency of the new algorithm, and the experiment results show that the new algorithm can achieve the cooperation strategy much faster than the primitive multiagent reinforcement learning algorithm.

  11. Monitoring Corrosion of Steel Bars in Reinforced Concrete Structures

    OpenAIRE

    2014-01-01

    Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for eva...

  12. Durability of GFRP reinforcing bars and their bond in concrete

    OpenAIRE

    ROLLAND, Arnaud; Chataigner, Sylvain; QUIERTANT, Marc; Benzarti, Karim; Argoul, Pierre

    2015-01-01

    The use of composite reinforcing bars (rebars) for the reinforcement of concrete appears as an attractive solution to prevent corrosion, which is the main pathology encountered on concrete structures. Although such rebars are being used for more than ten years, there is a clear lack of knowledge regarding their durability, especially under alkaline environment. This paper aims at investigating the evolutions of tensile properties and bond in concrete of GFRP (Glass Fiber Reinforced Polymer...

  13. Concrete cover cracking due to uniform reinforcement corrosion

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe; Michel, Alexander; Geiker, Mette Rica;

    2013-01-01

    and reinforcement de-passivation is a frequently used limit state. The present paper investigates an alternative limit state: corrosion-induced cover cracking. Results from numerical simulations of concrete cover cracking due to reinforcement corrosion are presented. The potential additional service...... from the numerical simulations reveal that, depending on the serviceability limit state applied, the service life of a reinforced concrete structure can be increased significantly by allowing minor damage of the cover....

  14. Relationship between food habituation and reinforcing efficacy of food

    OpenAIRE

    Carr, Katelyn A.; Epstein, Leonard H.

    2011-01-01

    Reinforcing value and habituation are two processes that have been used to study eating behaviors, but no research has examined their relationship, how they relate to energy intake, and whether they respond in a similar manner to food deprivation. Twenty-two female subjects were randomized to food deprived or non-deprived conditions, and assessed for food reinforcement, habituation to food and ad libitum eating. Results showed food reinforcement and habituation are correlated (r = 0.62, p = 0...

  15. The Behavior of Foundation Soil with and without Geosyntethic Reinforcement

    Directory of Open Access Journals (Sweden)

    Felicia NICULESCU-ENACHE

    2013-07-01

    Full Text Available This paper presents the computed diagrams showing the soil behavior in two alternative calculation hypotheses (with/without geogrid reinforcement will be compared, so that the positive effect of two geogrid layers used for reinforcement is revealed. The diagrams show that the use of reinforcement layers contributes to a more uniform distribution of loads and to the decrease of the pressure, thus increasing the bearing capacity of the soil.

  16. Hybrid fiber and nanopowder reinforced composites for wind turbine blades

    Directory of Open Access Journals (Sweden)

    Nikoloz M. Chikhradze

    2015-01-01

    Full Text Available The results of an investigation into the production of wind turbine blades manufactured using polymer composites reinforced by hybrid (carbon, basalt, glass fibers and strengthened by various nanopowders (oxides, carbides, borides are presented. The hybrid fiber-reinforced composites (HFRC were manufactured with prepreg technology by molding pre-saturated epoxy-strengthened matrix-reinforced fabric. Performance of the manufactured composites was estimated with values of the coefficient of operating condition (COC at a moderate and elevated temperature.

  17. RILEM TC : reinforcement of timber elements in existing structures

    OpenAIRE

    Tannert, Thomas; Branco, Jorge M.; Riggio, Mariapaola

    2013-01-01

    The paper reports on the activities of the RILEM technical committee “Reinforcement of Timber Elements in Existing Structures”. The main objective of the committee is to coordinate the efforts to improve the reinforcement practice of timber structural elements. Recent developments related to structural reinforcements can be grouped into three categories: (i) addition of new structural systems to support the existing structure; (ii) configuration of a composite system; and (iii)...

  18. Experimental verification of construction joints by reinforcement loops

    OpenAIRE

    Contreras, Catalina P.; Aparicio Bengoechea, Ángel Carlos; Casas Rius, Joan Ramon

    2011-01-01

    The present work delivers one experimental study of a new type of joint reinforcement for boxgirder bridges constructed evolutionarily, seeking to reduce execution time, improve formwork placement inside the box section, and minimize work risks. For this reason, failure tests are carried out in reinforced concrete slabs, comparing the experimental results of proposed joint with continuous reinforcement and a loop union according to DIN 1045. The results are delivered in terms of resistance...

  19. Modelling of the fracture toughness anisotropy in fiber reinforced concrete

    OpenAIRE

    Tarasovs, S.; J. Krūmiņš; V. Tamužs

    2016-01-01

    Steel fiber reinforced concrete is potentially very promising material with unique properties, which currently is widely used in some applications, such as floors and concrete pavements. However, lack of robust and reliable models of fiber reinforced concrete fracture limits its application as structural material. In this work a numerical model is proposed for predicting the crack growth in fiber reinforced concrete. The mixing of the steel fibers with the concrete usually creates...

  20. Substitutability between conditioned and primary reinforcers in discrimination acquisition.

    OpenAIRE

    Williams, B A; Dunn, R

    1991-01-01

    Rats and pigeons were trained on a series of reversals of a conditional simultaneous discrimination. The percentage of reinforcement for correct trials was varied across reversals. When nonreinforced correct trials produced the same feedback as incorrect trials, the number of errors to reach an acquisition criterion was greater for smaller percentages of reinforcement, but the number of reinforcers required was either approximately constant or smaller for the smaller percentages. When a stimu...

  1. Mechanical Properties of Glass Fiber Composites Reinforced by Textile Fabric

    OpenAIRE

    Macanovskis, Arturs; Krasnikovs, Andrejs; Kononova, Olga; Harjkova, Galina; Yevstignejevs, Vladislav

    2015-01-01

    Interest to structural application of textile reinforced polymer matrix composite materials (CM) is growing during last years. In different branches of machine building, aerospace, automotive and others industries we can find structural elements preferably be produced using such reinforcement. At the same time, such materials are exhibiting elastic and strength properties scatter. In the framework of the present investigation, we observe yarn penetrated by a resin in a composite as a reinforc...

  2. Punching tests of slabs with low reinforcement ratios

    OpenAIRE

    Guandalini, Stefano; Burdet, Olivier; Muttoni, Aurelio

    2009-01-01

    The results of a test series on the punching behavior of slabs with varying flexural reinforcement ratios and without transverse reinforcement are presented. The aim of the tests was to investigate the behavior of slabs failing in punching shear with low reinforcement ratios. The size of the specimens and of the aggregate was also varied to investigate its effect on punching shear. Measurements at the concrete surface as well as through the thickness of the specimens allowed the observation o...

  3. Mechanism of Reinforcement on Inwall of Coal Mine Shaft Wall

    OpenAIRE

    Jinlong Liu; Luwang Chen; Jili Wang

    2013-01-01

    Based on the theory of elasticity, the analytic solution of temperature stress on shaft wall of coal mine with reinforcement on inwall is deduced. It is shown that with the increment of reinforcement stress Pa, the radial compressive stress &sigmar become larger, the vertical compressive stress &sigmaz become less, while the circumferential stress &sigma &theta changed from compressive stress to tensile stress. The stability of shaft wall enhanced with vertical stress reduced by reinforcement...

  4. Use of Woven Fabrics for Strengthening of Reinforced Concrete Beams

    OpenAIRE

    Parthraj R. Puranik; Deval A. Vasavada

    2014-01-01

    Worldwide, a great deal of research is currently being conducted concerning the use of fiber reinforced plastic wraps, laminates and sheets in the repair and strengthening of reinforced concrete (RC) members. Fibre-reinforced polymer (FRP) application is a very effective way to repair and strengthen structures that have become structurally weak over their life span. But the use of woven fabrics for strengthening RC members has not been much investigated. Woven fabrics though cannot provide co...

  5. Mechanical properties of rice husk flour reinforced epoxy biocomposite

    OpenAIRE

    Neeraj Bisht; Prakash Chandra Gope

    2015-01-01

    A bio-composite reinforced with rice husk flour in epoxy resin has been developed. The effect of fibre treatment and weight percentage of rice husk on the mechanical properties was studied and compared with wood dust reinforced epoxy composite. It was observed that addition of rice husk as filler is detrimental to almost all the mechanical properties. About 51% and 26.8% decrease in ultimate strength and Young’s Modulus for 40 wt% untreated rice husk reinforcement was observed. Th...

  6. Technological and organizational aspect of steel fiber reinforced concrete construction

    OpenAIRE

    Brodnik, Aleš

    2010-01-01

    The present work is divided in an introduction, five substantive chapters and conclusions. The first substantive chapter represents development of the usage of separate sorts of fibers, suitable to reinforce the concrete structure. The rest of the chapter concentrates on the detailed presentation of steel fiber reinforced concrete. So in the second substantive chapter steel fibers that are used for reinforcing the concrete structure are defined, together with the production procedures, their ...

  7. Influence of Additives on Reinforced Concrete Durability

    Directory of Open Access Journals (Sweden)

    Neverkovica Darja

    2014-12-01

    Full Text Available The article presents the results of the research on carbonation and chloride induced corrosion mechanisms in reinforced concrete structures, based on three commercially available concrete admixtures: Xypex Admix C-1000, Penetron Admix and Elkem Microsilica. Carbonation takes place due to carbon dioxide diffusion, which in the required amount is present in the air. Chlorides penetrate concrete in case of the use of deicing salt or structure exploitation in marine atmosphere. Based on the implemented research, Elkem Microsilica is the recommended additive for the use in aggressive environmental conditions. Use of Xypex Admix C-1000 and Penetron Admix have only average resistance to the aggressive environmental impact.

  8. Reinforcement Data for Fire Safety Design

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    2004-01-01

    Idealized materials data are derived from a number of test series reported in the literature and made by the author. The data cover a variety of reinforcing steels from mild steel, deformed bars and cold worked bars to cold drawn prestressing steels. Processes are described, which are responsible...... calculations instead of the more troublesome application of curves or tables. This new idealized representation is compared with test data and with other idealized curves for the materials presented, and recommended design values are given. Warnings are given for misleading curves and expressions from the...

  9. Reinforced concrete columns of variable cross section

    OpenAIRE

    Brant, N.F.A.

    1984-01-01

    The results of a series of 19 full scale tests carried out on pin-ended reinforced concrete columns are reported. The columns tested had either tapered rectangular sections along the length or octagonal cross sections. All columns, except the last 6, were subjected to uniaxial eccentricities at one of the ends (the stronger end), and a nominally concentric load at the other end. For the case of the last six columns the loading applied at the stronger end was biaxially eccentric. For each of t...

  10. Thermographic inspection of fiber reinforced plastics

    International Nuclear Information System (INIS)

    Thermographic inspection methods were studied to detect the flaws in Fiber Reinforced Plastics (FRP) laminates. Effects of size and location of flaws in FRP laminates and thermal properties of FRP on the detectability were numerically analyzed using finite difference method. Flat bottom holes in GFRP laminate and artificial delaminations made of teflon sheets in GFRP and CFRP laminates were tested using scanning heat source and liquid crystal films. The location of flaws could be determined from the change of liquid crystal colors which represents the distribution of surface temperature of FRP laminates.

  11. Reinforcement Learning in BitTorrent Systems

    OpenAIRE

    Izhak-Ratzin, Rafit; Park, Hyunggon; van der Schaar, Mihaela

    2010-01-01

    Recent research efforts have shown that the popular BitTorrent protocol does not provide fair resource reciprocation and may allow free-riding. In this paper, we propose a BitTorrent-like protocol that replaces the peer selection mechanisms in the regular BitTorrent protocol with a novel reinforcement learning (RL) based mechanism. Due to the inherent opration of P2P systems, which involves repeated interactions among peers over a long period of time, the peers can efficiently identify free-r...

  12. Fatigue of continuous fiber reinforced metallic materials

    Science.gov (United States)

    Johnson, W. S.; Mirdamadi, M.; Bakuckas, J. G., Jr.

    1993-01-01

    The complex damage mechanisms that occur in fiber reinforced advanced metallic materials are discussed. As examples, results for several layups of SCS-6/Ti-15-3 composites are presented. Fatigue tests were conducted and analyzed for both notched and unnotched specimens at room and elevated temperatures. Test conditions included isothermal, non-isothermal, and simulated mission profile thermomechanical fatigue. Test results indicated that the stress in the 0 degree fibers is the controlling factor for fatigue life for a given test condition. An effective strain approach is presented for predicting crack initiation at notches. Fiber bridging models were applied to crack growth behavior.

  13. Reinforcement learning: Solving two case studies

    Science.gov (United States)

    Duarte, Ana Filipa; Silva, Pedro; dos Santos, Cristina Peixoto

    2012-09-01

    Reinforcement Learning algorithms offer interesting features for the control of autonomous systems, such as the ability to learn from direct interaction with the environment, and the use of a simple reward signalas opposed to the input-outputs pairsused in classic supervised learning. The reward signal indicates the success of failure of the actions executed by the agent in the environment. In this work, are described RL algorithmsapplied to two case studies: the Crawler robot and the widely known inverted pendulum. We explore RL capabilities to autonomously learn a basic locomotion pattern in the Crawler, andapproach the balancing problem of biped locomotion using the inverted pendulum.

  14. Nanotube reinforced thermoplastic polymer matrix composites

    Science.gov (United States)

    Shofner, Meisha Lei

    The inherent high strength, thermal conductivity, and electrical conductivity make nanotubes attractive reinforcements for polymer matrix composites. However, the structure that makes them desirable also causes highly anisotropic properties and limited reactivity with other materials. This thesis isolates these problems in two separate studies aimed at improving mechanical properties with single wall nanotube (SWNT) reinforced thermoplastic polymer composites. The two studies demonstrate the effect of solid freeform fabrication (SFF) and chemical functionalization on anisotropy and limited reactivity, respectively. Both studies showed mechanical property improvements. The alignment study demonstrates a maximum increase of 93% in tensile modulus with single wall nanotubes (SWNTs). The chemical functionalization study shows a larger increase in storage modulus for functionalized SWNTs as compared to purified SVWNTs with respective increases of 9% and 44% in storage modulus. Improved interfacial properties are also observed as a decrease in mechanical damping. Maximum property increases in composites are obtained when nanotubes are aligned, requiring additional processing consideration to the anisotropic structure. Melt spinning and extrusion processing effectively align nanotubes, but the end product of these techniques, composite fibers, requires further processing to be incorporated into finished parts. Extrusion-based SFF is a novel technique for processing nanotube reinforced composites because it allows for the direct fabrication of finished parts containing aligned nanotubes. SFF processing produces parts containing preferentially oriented nanotubes with improved mechanical properties when compared to isotropic composites. Functionalization of the nanotube surface disrupts the rope structure to obtain smaller ropes and promote further interfacial bonding. The chemically inert nature of nanotubes resulting from a structure containing few defects and the

  15. Fracture Toughness Prediction for MWCNT Reinforced Ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H.; Nguyen, Ba Nghiep

    2013-09-01

    This report describes the development of a micromechanics model to predict fracture toughness of multiwall carbon nanotube (MWCNT) reinforced ceramic composites to guide future experimental work for this project. The modeling work described in this report includes (i) prediction of elastic properties, (ii) development of a mechanistic damage model accounting for matrix cracking to predict the composite nonlinear stress/strain response to tensile loading to failure, and (iii) application of this damage model in a modified boundary layer (MBL) analysis using ABAQUS to predict fracture toughness and crack resistance behavior (R-curves) for ceramic materials containing MWCNTs at various volume fractions.

  16. Strength of Cracked Reinforced Concrete Disks

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1999-01-01

    The paper deals with models, based on the theory of plasticity, to be used in strength assessments of reinforced concrete disks suffering from different kinds of cracking. Based on the assumption that the sliding strength of concrete is reduced in sections where cracks are located, solutions for...... the shear strength of disks with initial cracks and disks suffering from isotropic cracking are presented. Furthermore, in the case of isotropicly cracked disks subjected to arbitrary in-plane loading, a general yield condition is derived....

  17. Mechanical Properties of Cellulose Microfiber Reinforced Polyolefin

    Science.gov (United States)

    Kobayashi, Satoshi; Yamada, Hiroyuki

    Cellulose microfiber (CeF) has been expected as a reinforcement of polymer because of its high modulus and strength and lower cost. In the present study, mechanical properties of CeF/polyolefin were investigated. Tensile modulus increased with increasing CeF content. On the other hand, tensile strength decreased. Fatigue properties were also investigated with acoustic emission measurement. Stiffness of the composites gradually decreased with loading. Drastic decrease in stiffness was observed just before the final fracture. Based on the Mori-Tanaka's theory, the method to calculate modulus of CeF were proposed to evaluate dispersion of CeF.

  18. Reinforcement Data for Fire Safety Design

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    2004-01-01

    for the deterioration of the materials when they are heated and cooled down. A simple expression is established for the description of deterioration curves for fire-exposed materials such as concrete and reinforcement by means of 5 parameters, which may be used as input data for structural fire safety...... structural codes. The paper serves as a basis for a number of papers presenting calculation methods developed by the author for the load bearing capacity of constructions of any concrete at any time of any fire exposure. Some of these methods and materials data are adopted in the CEN code1 and national codes...

  19. Design of Reinforced Concrete Elements Under Fire

    Directory of Open Access Journals (Sweden)

    P. Mihai

    2008-01-01

    Full Text Available Fire safety regulations can have a major impact on many aspects of the overall design of a building, including layout, aesthetics, function, and cost. Rapid developments in modern building technology in the last decades often have resulted in unconventional structures and design solutions. Because the world is developed continuously, the physical size of buildings increases continually; there is a tendency to build large underground car parks, warehouses, and shopping complexes. As a result, we have a worldwide movement to replace prescriptive building codes with ones based on performance. The paper presents the basic principles for the designing process of reinforced concrete elements under fire.

  20. Stochastic Modeling of Reinforced Concrete Structures Exposed to Chloride Attack

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Frier, Christian

    2003-01-01

    For many reinforced concrete structures corrosion of reinforcement is an important problem since it can result in expensive maintenance and repair actions. Further, a significant reduction of the load-bearing capacity can occur. One mode of corrosion initiation is that the chloride content around...... the reinforcement exceeds a critical threshold value. In the present paper a stochastic model is described by which the chloride content in a reinforced concrete structure can be estimated. The chloride ingress is modeled by a 2-dimensional diffusion process and the diffusion coefficient, surface...

  1. Stochastic modeling of reinforced concrete structures exposed to chloride attack

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Frier, Christian

    2004-01-01

    For many reinforced concrete structures corrosion of reinforcement is an important problem since it can result in expensive maintenance and repair actions. Further, a significant reduction of the load-bearing capacity can occur. One mode of corrosion initiation is that the chloride content around...... the reinforcement exceeds a critical threshold value. In the present paper a stochastic model is described by which the chloride content in a reinforced concrete structure can be estimated. The chloride ingress is modeled by a 2-dimensional diffusion process and the diffusion coefficient, surface...

  2. Finite element analysis of the stiffness of fabric reinforced composites

    Science.gov (United States)

    Foye, R. L.

    1992-01-01

    The objective of this work is the prediction of all three dimensional elastic moduli of textile fabric reinforced composites. The analysis is general enough for use with complex reinforcing geometries and capable of subsequent improvements. It places no restrictions on fabric microgeometry except that the unit cell be determinate and rectangular. The unit cell is divided into rectangular subcells in which the reinforcing geometries are easier to define and analyze. The analysis, based on inhomogeneous finite elements, is applied to a variety of weave, braid, and knit reinforced composites. Some of these predictions are correlated to test data.

  3. Research progress of microbial corrosion of reinforced concrete structure

    Science.gov (United States)

    Li, Shengli; Li, Dawang; Jiang, Nan; Wang, Dongwei

    2011-04-01

    Microbial corrosion of reinforce concrete structure is a new branch of learning. This branch deals with civil engineering , environment engineering, biology, chemistry, materials science and so on and is a interdisciplinary area. Research progress of the causes, research methods and contents of microbial corrosion of reinforced concrete structure is described. The research in the field is just beginning and concerted effort is needed to go further into the mechanism of reinforce concrete structure and assess the security and natural life of reinforce concrete structure under the special condition and put forward the protective methods.

  4. Geosynthetic Reinforcement of Sand-Mat Layer above Soft Ground

    Directory of Open Access Journals (Sweden)

    Jong-Beom Park

    2013-11-01

    Full Text Available In order to improve the bearing capacity of soft ground for the purpose of getting trafficability of construction vehicles, the reinforcement of geosynthetics for sand-mat layers on soft ground has often been used. As the strength of the geosynthetics increases, and the sand-mat system becomes stronger, the bearing capacity of sand-mat systems will be increased. The depths of geosynthetics, reinforced in sand-mat layers, were varied with respect to the width of footing. The tensile strengths of geosynthetics were also varied to evaluate the effect of reinforcement on the bearing capacity of soft ground. The dispersion angles, with varying sand-mat thicknesses, were also determined in consideration of the tensile strength of geosynthetics and the depths of reinforcement installations. The bearing capacity ratios, with the variation of footing width and reinforced embedment depth, were determined for the geosynthetics-only, reinforced soft ground, 1-layer sand-mat system and 2-layer sand-mat system against the non-reinforced soft ground. From the test results of various models, a principle that better explains the concept of geosynthetic reinforcement has been found. On the basis of this principle, a new bearing capacity equation for practical use in the design of geosynthetically reinforced soft ground has been proposed by modifying Yamanouchi’s equation.

  5. Custom fabrication of reinforced lithium disilicate ceramic ingot

    Science.gov (United States)

    Chander, Gopi Naveen; Sasikala, C.; Mutukumar, B.; Dhanasekar, N.

    2016-01-01

    A method of formulating a reinforcement lithium disilicate ceramic ingot was proposed. The ceramic ingot was broken manually with a mallet to finer particles. The sectioned ingot is ball milled along with 10% of nano zirconia by weight to obtain the desired powder. The reinforced powder is condensed in a 5 ml disposable syringe by powder slurry technique. The compacted ceramic were sintered at 900°C to obtain ceramic ingots. The reinforced ceramic ingots were used in pressable ceramic machines to obtain the desired advantages of zirconia reinforcement and pressable ceramic system.

  6. Toughened microstructures for ductile phase reinforced molybdenum disilicide

    International Nuclear Information System (INIS)

    Various morphologies of ductile Nb refractory metal reinforcement are incorporated into a MoSi2 matrix using powder metallurgy, including single-ply laminates, continuous metal ribbons and sections of 2-dimensional wire mesh. Hot forging techniques are used to redistribute the reinforcement and change the dimensions and the aspect ratio of the reinforcing metal ligaments. Work-of-rupture measurements are conducted on bend test specimens and precracked tensile specimens of the composite so that the toughness contribution from the various ductile metal morphologies can be assessed according to its effectiveness. Accompanying microstructural examination of crack bridging interaction with the reinforcement is conducted

  7. Theoretical study for Bond between Reinforcement steel and Concrete

    Directory of Open Access Journals (Sweden)

    usama mostafa mahran

    2013-04-01

    Full Text Available The behavior and load carrying behavior of reinforced concrete structures is influence by the interaction between the concrete and reinforcement. The stress transfer between reinforcement and concrete in the longitudinal direction of the bars is called bond. An essential feature of reinforced concrete is the bond between steel and concrete. Anchorage of reinforcement depends on the bond between steel and concrete, crack width and crack spacing are mainly governed by it. So, stiffness, deformation and dynamic behavior are influenced by it, and in reverse loading damping and energy dissipation is a function of bond. This is one of the reasons why bond has been, and still is, a topic of fundamental and applied research. Bond stress is the equivalent unit shear stress acting in parallel to the reinforcing bar on the interface between reinforcing steel bar and concrete. Due to the transfer of forces through bond stress, between the reinforcing rebar and concrete, the force in the reinforcing bar changes along its length. Because bond stress is thought of as stress per unit area of bar surface, it is related to the rate of change of steel stress. Consequently, to have bond stress it is necessary to have a changing steel stress. In cases of high stress at the contact interface, near cracks or end anchorages, the bond stresses are related to relative displacements between concrete and steel. These relative displacements, which are caused by different average strains in the concrete and the steel, are usually called bond-slip (t-d.

  8. Application and development of stainless steel reinforced concrete structure

    Directory of Open Access Journals (Sweden)

    Meng Xian Hong

    2016-01-01

    Full Text Available Now reinforced concrete structure in our country develops very fast, and reinforced concrete structure has been widely applied by various buildings. But with the deepening of the research experts and scholars, they found in some areas where high corrosion of reinforced concrete structure with the increase of service time, the concrete cracks, and led to the internal steel bar corrosion conditions. In the face of these problems, the experts used stainless steel applied to the study of concrete. In this paper, the stainless stell reinforced concrete structure of the application and development status of made briefly.

  9. Superelastic SMA–FRP composite reinforcement for concrete structures

    International Nuclear Information System (INIS)

    For many years there has been interest in using fiber-reinforced polymers (FRPs) as reinforcement in concrete structures. Unfortunately, due to their linear elastic behavior, FRP reinforcing bars are never considered for structural damping or dynamic applications. With the aim of improving the ductility and damping capability of concrete structures reinforced with FRP reinforcement, this paper studies the application of SMA–FRP, a relatively novel type of composite reinforced with superelastic shape memory alloy (SMA) wires. The cyclic tensile behavior of SMA–FRP composites are studied experimentally and analytically. Tests of SMA–FRP composite coupons are conducted to determine their constitutive behavior. The experimental results are used to develop and calibrate a uniaxial SMA–FRP analytical model. Parametric and case studies are performed to determine the efficacy of the SMA–FRP reinforcement in concrete structures and the key factors governing its behavior. The results show significant potential for SMA–FRP reinforcement to improve the ductility and damping of concrete structures while still maintaining its elastic characteristic, typical of FRP reinforcement

  10. Strengthening of reinforced concrete circular columns using glass fibre reinforced polymers

    Directory of Open Access Journals (Sweden)

    Manish kumar Tiwari

    2014-04-01

    Full Text Available Seismic retrofitting of reinforced concrete members vulnerable to strong earthquakes is a great problem. It has long been recognized that confinement to concrete compression members not only increase the strength but improve ductility significantly. The present study focuses on the behavior of reinforced concrete specimens strengthened using glass fiber reinforced polymer (GFRP subjected to axial compressive loading. In this study specimen of circular cross section having length to diameter ratio of 2.0 and 0.96% longitudinal reinforcement were prepared and tested for 28 days compressive strength. The specimens were wrapped with 0,2,4,6 and 8 layers of GFRP outside the surface of the specimens as confinement. The test results showed that there is a significant increase in the strength of specimen with the increase of confinement layers on the specimen. The 28 days compressive strength of specimen wrapped with 8 layers of GRRP was increased by 47% as compared to the strength of specimen without any confinement.

  11. Strength Modeling of Reinforced Concrete Beam with Externally Bonded FRP Reinforcement

    Directory of Open Access Journals (Sweden)

    N. Pannirselvam

    2008-01-01

    Full Text Available This research study presents the evaluation of the structural behaviour of reinforced concrete beams with externally bonded Fibre Reinforced Polymer (FRP reinforcements. Three different steel ratios with two different Glass Fibre Reinforced Polymer (GFRP types and two different thicknesses in each type of GFRP were used. Totally fifteen rectangular beams of 3 m length were cast. Three rectangular beams were used as reference beam (Control Beams and the remaining were fixed with GFRP laminates on the soffit of the rectangular beam. The variables considered for the study includes longitudinal steel ratio, type of GFRP laminates, thickness of GFRP laminates and composite ratios. Flexural test, using simple beam with third-point loading was adopted to study the performance of FRP plated beams interms flexural strength, deflection, ductility and was compared with the unplated beams. The test results show that the beams strengthened with GFRP laminates exhibit better performance. The flexural strength and ductility increase with increase in thickness of GFRP plate. The increase in first crack loads was up to 88.89% for 3 mm thick WRGFRP plates and 100.00% for 5 mm WRGFRP plated beams and increase in ductility interms of energy and deflection was found to be 56.01 and 64.69% respectively with 5 mm thick GFRP plated beam. Strength models were developed for predicting the flexural strength (ultimate load, service load and ductility of FRP beams. The strength model developed give prediction matching the measurements.

  12. Design and behavior of reinforced concrete beams strengthened with fiber-reinforced plastics (FRP)

    Science.gov (United States)

    El-Mihilmy, Mahmoud Tharwat

    A comprehensive investigation of the design and behavior of reinforced concrete beams strengthened with externally bonded FRP laminates has been conducted. The study has confirmed the applicability of the strain compatibility method for calculating the increased ultimate moment capacity of the repaired beams. An upper limit to the amount of FRP that can be added to a specific structure was recommended to ensure ductile behavior. Design charts to facilitate calculations of the ultimate moment capacity for reinforced concrete beams strengthened with FRP laminates were developed. The results of a subsequent parametric investigation indicate that strengthening reinforced concrete beams with FRP laminates can enhance their ultimate capacity by as much as three times the original strength, especially for beams with a low steel ratio. It was also determined that, increasing the concrete compressive strength and the FRP modulus of elasticity increases the beam ultimate flexural capacity significantly; however, the repaired beams are less ductile than the pre-repaired concrete beams. During the course of the study, it had been noticed that the current ACI recommended method for calculating deflections for ordinary reinforced concrete beams does not render an accurate estimate for reinforced concrete beams strengthened with FRP laminates. A simplified equation for predicting the deflection of reinforced concrete beams repaired with FRP was developed and verified with comparisons to experimental results. The effectiveness of strengthening an existing bridge with externally bonded FRP laminates was investigated through comprehensive static and dynamic finite element analyses. The results of these analyses correlate well with field load test results. The repaired girders exhibited an average reduction in reinforcing steel stresses of 11 percent and an average reduction in midspan girder deflections of 9 percent. The results of the study also indicated that existing methods for

  13. Effects of reinforcer magnitude on responding under differential-reinforcement-of-low-rate schedules of rats and pigeons.

    Science.gov (United States)

    Doughty, Adam H; Richards, Jerry B

    2002-07-01

    Experiment I investigated the effects of reinforcer magnitude on differential-reinforcement-of-low-rate (DRL) schedule performance in three phases. In Phase 1, two groups of rats (n = 6 and 5) responded under a DRI. 72-s schedule with reinforcer magnitudes of either 30 or 300 microl of water. After acquisition, the water amounts were reversed for each rat. In Phase 2, the effects of the same reinforcer magnitudes on DRL 18-s schedule performance were examined across conditions. In Phase 3, each rat responded unider a DR1. 18-s schedule in which the water amotnts alternated between 30 and 300 microl daily. Throughout each phase of Experiment 1, the larger reinforcer magnitude resulted in higher response rates and lower reinforcement rates. The peak of the interresponse-time distributions was at a lower value tinder the larger reinforcer magnitude. In Experiment 2, 3 pigeons responded under a DRL 20-s schedule in which reinforcer magnitude (1-s or 6-s access to grain) varied iron session to session. Higher response rates and lower reinforcement rates occurred tinder the longer hopper duration. These results demonstrate that larger reinforcer magnitudes engender less efficient DRL schedule performance in both rats and pigeons, and when reinforcer magnitude was held constant between sessions or was varied daily. The present results are consistent with previous research demonstrating a decrease in efficiency as a function of increased reinforcer magnituide tinder procedures that require a period of time without a specified response. These findings also support the claim that DRI. schedule performance is not governed solely by a timing process. PMID:12144310

  14. Effects of reinforcer rate and reinforcer quality on time allocation: Extensions of matching theory to educational settings

    OpenAIRE

    Neef, Nancy A.; Mace, F. Charles; Shea, Michael C.; Shade, Doran

    1992-01-01

    We examined how 3 special education students allocated their responding across two concurrently available tasks associated with unequal rates and equal versus unequal qualities of reinforcement. The students completed math problems from two alternative sets on concurrent variable-interval (VI) 30-s VI 120-s schedules of reinforcement. During the equal-quality reinforcer condition, high-quality (nickels) and low-quality items (“program money” in the school's token economy) were alternated acro...

  15. Field Test of a Bridge Deck with Glass Fiber Reinforced Polymer Bars as the Top Mat of Reinforcement

    OpenAIRE

    Harlan, Matthew

    2004-01-01

    The primary objective of this research project was to perform live load tests on a bridge deck with GFRP reinforcement in the field under service conditions. The strains and deflections in the span reinforced with GFRP in the top mat were recorded under a series of truck crossings, and these were compared to the span reinforced with all steel bars under identical loading conditions, as well as design values and other test results. Transverse strains in the GFRP bars, girder distribution fac...

  16. Performance of a Bridge Deck with Glass Fiber Reinforced Polymer Bars as the Top Mat of Reinforcement

    OpenAIRE

    Kimberly A. Phillips; Matthew Harlan; Roberts-Wollmann, Carin L.; Cousins, Thomas E.

    2005-01-01

    The purpose of this research was to investigate the performance of glass fiber reinforced polymer (GFRP) bars as reinforcement for concrete decks. Today's rapid bridge deck deterioration is calling for a replacement for steel reinforcement. The advantages of GFRP such as its high tensile strength, light weight, and resistance to corrosion make it an attractive alternative to steel. The deck of one end-span of the Gills Creek Bridge was constructed with GFRP bars as the top mat and epoxy-coate...

  17. Performance of a Bridge Deck with Glass Fiber Reinforced Polymer (GFRP) Bars as the Top Mat of Reinforcement

    OpenAIRE

    Phillips, Kimberly Ann

    2004-01-01

    The purpose of this research was to investigate the effectiveness and durability of GFRP bars as reinforcement for concrete decks. Today's rapid bridge deck deterioration is calling for a replacement for steel reinforcement. The advantages of GFRP such as its high tensile strength, light weight, and resistance to corrosion make it an attractive alternative to steel. The first objective of this research was to perform live load testing on a bridge deck reinforced with GFRP in one span and...

  18. Textile-reinforced mortar (TRM) versus fiber-reinforced polymers (FRP) in shear strengthening of concrete beams

    OpenAIRE

    Tetta, Z.C.; Koutas, L.N.; Bournas, D.A.

    2015-01-01

    This paper presents an experimental study on shear strengthening of rectangular reinforced concrete (RC) beams with advanced composite materials. Key parameters of this study include: (a) the strengthening system, namely textile-reinforced mortar (TRM) jacketing and fiber-reinforced polymer (FRP) jacketing, (b) the strengthening configuration, namely side-bonding, U-wrapping and full-wrapping, and (c) the number of the strengthening layers. In total, 14 RC beams were constructed and tested un...

  19. Effects of noncontingent reinforcement on problem behavior and stimulus engagement: the role of satiation, extinction, and alternative reinforcement.

    OpenAIRE

    Hagopian, L P; Crockett, J L; Stone, M.; DeLeon, I G; Bowman, L G

    2000-01-01

    This study examined the effects of noncontingent reinforcement (NCR) with and without extinction on problem behavior and stimulus engagement (consumption of reinforcement) of 4 participants. Reductions in problem behavior using NCR have frequently been attributed to both satiation of the reinforcer and extinction. In the current study, aspects of the NCR treatment effects were difficult to explain based solely on either a satiation or an extinction account. Specifically, it was found that sti...

  20. Improving Student Understanding of Operations Management Techniques through a Rolling Reinforcement Strategy.

    Science.gov (United States)

    Mukherjee, Arup

    2002-01-01

    Operations management problems were taught to 41 students with same-day reinforcement and to 67 with rolling reinforcement (a day after teaching). Rolling reinforcement resulted in 71.4% mean score compared to 55.4%. Use of two reinforcements had a positive but not significant impact. More reinforcement helped significantly more students achieve…

  1. Generating Variable and Random Schedules of Reinforcement Using Microsoft Excel Macros

    Science.gov (United States)

    Bancroft, Stacie L.; Bourret, Jason C.

    2008-01-01

    Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time.…

  2. Polypropylene matrix composites reinforced with coconut fibers

    Directory of Open Access Journals (Sweden)

    Maria Virginia Gelfuso

    2011-09-01

    Full Text Available Polypropylene matrix composites reinforced with treated coconut fibers were produced. Fibers chemically treated (alkalization-CCUV samples or mechanically treated (ultrasonic shockwave-CMUV samples were dried using UV radiation. The goal was to combine low cost and eco-friendly treatments to improve fiber-matrix adhesion. Composite samples containing up to 20 vol. (% of untreated and treated coconut fibers were taken from boxes fabricated by injection molding. Water absorption and mechanical properties were investigated according to ASTM D570-98 and ASTM D638-03, respectively. Electrical characterizations were carried out to identify applications of these composites in the electrical sector. NBR 10296-Electrical Tracking Standard (specific to industry applications and conductivity measurements were obtained applying 5 kV DC to the samples. CMUV samples containing 5 vol. (% fiber presented superior tensile strength values (σ~28 MPa compared to the untreated fibers composite (σ~22 MPa or alkali treatment (σ~24 MPa. However, CMUV composites containing 10 vol. (% fiber presented best results for the electrical tracking test and electrical resistivity (3 × 10(7 Ω.m. The results suggest that composites reinforced with mechanically treated coconut fibers are suitable for electrical applications.

  3. UV-Curing of Nanoparticle Reinforced Acrylates

    International Nuclear Information System (INIS)

    Polymer reinforcement by silica and alumina nanoparticles evidently yields improved surface hardness. Single mixing of nanoparticles into an acrylate formulations, however, leads to highly viscous solutions inappropriate for coating procedures. The incompatibility of inorganic fillers and organic polymers can be avoided by surface modification providing an interface between the two dissimilar materials. For example, vinyltrimethoxysilane (VTMO) can react via hydrolysis/condensation reactions with hydroxyl groups present on the inorganic surface and should bond via the polymerisation-active vinyl group to an acrylate resin through crosslinking reactions. Grafting reactions of surface OH groups and different trialkoxysilanes were studied by thermogravimetry, infrared, and multinuclear NMR spectroscopy. The copolymeri-zation of modified nanoparticles with the acrylate matrix has been investigated by 13C NMR spectroscopy. UV curing under nitrogen inertization revealed a lower reactivity of vinyl groups of VTMO-modified silica compared to grafted methacryloxypropyl-trimethoxysilane (MEMO) which showed complete conversion of olefinic carbons (signals at 120 - 140 ppm). Under conditions of oxygen inhibition, the effect of the kind and the concentration of photoinitiator on the photopoly-merization reaction was studied. Compared to neat polyacrylate coatings the nanocomposite materials exhibit markedly improved properties, e.g., heat, scratch, and abrasion resistance. However, a much better abrasion resistance was obtained for coatings containing both silica nano-particles and corundum microparticles. In particular cases, radiation curing with 172 nm photons generated by Xe excimer was performed to obtain structured polymer surfaces, i.e., matting of the reinforced acrylate coatings

  4. Nano-Aramid Fiber Reinforced Polyurethane Foam

    Science.gov (United States)

    Semmes, Edmund B.; Frances, Arnold

    2008-01-01

    Closed cell polyurethane and, particularly, polyisocyanurate foams are a large family of flexible and rigid products the result of a reactive two part process wherein a urethane based polyol is combined with a foaming or "blowing" agent to create a cellular solid at room temperature. The ratio of reactive components, the constituency of the base materials, temperature, humidity, molding, pouring, spraying and many other processing techniques vary greatly. However, there is no known process for incorporating reinforcing fibers small enough to be integrally dispersed within the cell walls resulting in superior final products. The key differentiating aspect from the current state of art resides in the many processing technologies to be fully developed from the novel concept of milled nano pulp aramid fibers and their enabling entanglement capability fully enclosed within the cell walls of these closed cell urethane foams. The authors present the results of research and development of reinforced foam processing, equipment development, strength characteristics and the evolution of its many applications.

  5. Reinforcement Learning by Comparing Immediate Reward

    CERN Document Server

    Pandey, Punit; Kumar, Shishir

    2010-01-01

    This paper introduces an approach to Reinforcement Learning Algorithm by comparing their immediate rewards using a variation of Q-Learning algorithm. Unlike the conventional Q-Learning, the proposed algorithm compares current reward with immediate reward of past move and work accordingly. Relative reward based Q-learning is an approach towards interactive learning. Q-Learning is a model free reinforcement learning method that used to learn the agents. It is observed that under normal circumstances algorithm take more episodes to reach optimal Q-value due to its normal reward or sometime negative reward. In this new form of algorithm agents select only those actions which have a higher immediate reward signal in comparison to previous one. The contribution of this article is the presentation of new Q-Learning Algorithm in order to maximize the performance of algorithm and reduce the number of episode required to reach optimal Q-value. Effectiveness of proposed algorithm is simulated in a 20 x20 Grid world dete...

  6. Applications of magnetically active fibre reinforced composites

    Science.gov (United States)

    Etches, Julie; Bond, Ian; Mellor, Philip

    2005-05-01

    As the application of fibre reinforced polymer composites (FRP) becomes more widespread there is a desire to add functionality beyond that of simple mechanical properties in order to facilitate the development of 'smart' materials. For example, the functionality being discussed in this paper is the imparting of significant magnetic properties to a FRP. This can take the form of soft magnetic performance for use in electrical machines or hard magnetic performance for novel forms of sensing or power generation. It has been demonstrated that by using hollow glass fibres as a reinforcement, magnetic material can be introduced into these fibres without significant effects on the structural behaviour of the FRP. The current studies have included the assessment of such a magnetic FRP in a variety of applications. The addition of hard magnetic materials, e.g. magnetite and barium ferrite, has been achieved through the use of nanopowders and the resulting FRP has been assessed for morphing structures applications. The magnitude of magnetic performance that can be currently achieved is controlled by the availability of suitable magnetic materials in fine powder form and the volume of magnetic material which can be incorporated within the fibres.

  7. Reinforcing of Cement Composites by Estabragh Fibres

    Science.gov (United States)

    Merati, A. A.

    2014-04-01

    The influence of Estabragh fibres has been studied to improve the performance characteristics of the reinforced cement composites. The concrete shrinkage was evaluated by counting the number of cracks and measuring the width of cracks on the surface of concrete specimens. Although, the Estabragh fibres lose their strength in an alkali environment of cement composites, but, the ability of Estabragh fibres to bridge on the micro cracks in the concrete matrix causes to decrease the width of the cracks on the surface of the concrete samples in comparison with the plain concrete. However, considering the mechanical properties of specimens such as bending strength and impact resistance, the specimens with 0.25 % of Estabragh fibre performed better in all respects compared to the physical and mechanical properties of reinforced cement composite of concrete. Consequently, by adding 0.25 % of Estabragh fibres to the cement composite of concrete, a remarkable improvement in physical and mechanical properties of fibre-containing cement composite is achieved.

  8. Reinforcement and recovery of timber structures

    Directory of Open Access Journals (Sweden)

    Antonio Alves Dias

    2006-02-01

    Full Text Available Preservation of timber structures is a reason for constant concern because their deterioration often involves compromising the historical patrimony, besides endangering the safety of the structure, and consequently, of their users. Many are the examples of churches, residences or other constructions where this manifestation is a fact. The technique of reinforcing structurally endangered pieces with the addition of natural or synthetic fibers, is an alternative that has been researched. In the group of synthetic fibers, fiberglass, carbon and aramid ones are included. On the other hand, it has been frequent in the restoration of old buildings, especially in Europe, the employment of materials that were not available in the past, aiming to achieve structural, acoustic and aesthetic benefits. On an existing timber structure floor, a concrete slab has been carried out, with an appropriate connection system among the parts, constituting the composite timber-concrete structures. This alternative has been considered as extraordinarily viable, because it gathers a series of convenience related with the durability and it presents better mechanic performance than conventional timber structures. In this work, the state-of-the-art of the use of fibers as structural reinforcement and of the timber-concrete composite structures, is presented.

  9. Effects of reinforcer magnitude on responding under differential-reinforcement-of-low-rate schedules of rats and pigeons.

    OpenAIRE

    Doughty, Adam H; Richards, Jerry B.

    2002-01-01

    Experiment I investigated the effects of reinforcer magnitude on differential-reinforcement-of-low-rate (DRL) schedule performance in three phases. In Phase 1, two groups of rats (n = 6 and 5) responded under a DRI. 72-s schedule with reinforcer magnitudes of either 30 or 300 microl of water. After acquisition, the water amounts were reversed for each rat. In Phase 2, the effects of the same reinforcer magnitudes on DRL 18-s schedule performance were examined across conditions. In Phase 3, ea...

  10. Structural performance evaluation on aging underground reinforced concrete structures. Part 1. Modeling of material degradation due to reinforcing steel corrosion

    International Nuclear Information System (INIS)

    This paper discusses effects of reinforcing steel corrosion on material properties of reinforced concrete and modeling of material degradation due to reinforcing steel corrosion used in a finite element method for structural analysis. First, we conducted a series of double-action tension tests on reinforced concrete specimens that were artificially corroded by stay current corrosion. We showed that the degradation ratio of yield strength of reinforcing steel agreeded well with maximum steel corrosion ratio and that tension softening of concrete became larger with the increase of corrosion degree. Second, based on these observations, reinforcement section area loss and initial tension strain due to reinforcement corrosion, a decrease in bond stress between reinforcement and concrete were employed for constructing the material model. To validate the devised modeling, the above -mentioned test results were numerically correlated. As a result, the analyzed load-strain relationships agreeded well with the experimental results under the condition of corrosion ratio 0-20%. Finally, as an application of experimental an analytical findings, we developed relationships between the parameters of modeling of material degradation and chloride induced deterioration progress as it widely accepted in maintenance practice for civil engineering reinforced concrete structures. (author)

  11. Confinement of Reinforced-Concrete Columns with Non-Code Compliant Confining Reinforcement plus Supplemental Pen-Binder

    Directory of Open Access Journals (Sweden)

    Anang Kristianto

    2012-11-01

    Full Text Available One of the important requirements for earthquake resistant building related to confinement is the use of seismic hooks in the hoop or confining reinforcement of reinforced-concrete column elements. However, installation of a confining reinforcement with a 135-degree hook is not easy. Therefore, in practice, many construction workers apply a confining reinforcement with a 90-degreehook (non-code compliant. Based on research and records of recent earthquakes in Indonesia, the use of a non-code compliant confining reinforcement for concrete columns produces structures with poor seismic performance. This paper presents a study that introduces an additional element that is expected to improve the effectiveness of concrete columns confined with a non-code compliant confining reinforcement. The additional element, named a pen-binder, is used to keep the non-code compliant confining reinforcement in place. The effectiveness of this element under pure axial concentric loading was investigatedcomprehensively.The specimens tested in this study were 18 concrete columns,with a cross-section of 170 mm x 170 mm and a height of 480 mm. The main test variables were the material type of the pen-binder, the angle of the hook, and the confining reinforcement configuration.The test results indicate that adding pen-binders can effectively improve the strength and ductility of the column specimens confined with a non-code compliant confining reinforcement

  12. Teaching Self-Control with Qualitatively Different Reinforcers

    Science.gov (United States)

    Passage, Michael; Tincani, Matt; Hantula, Donald A.

    2012-01-01

    This study examined the effectiveness of using qualitatively different reinforcers to teach self-control to an adolescent boy who had been diagnosed with an intellectual disability. First, he was instructed to engage in an activity without programmed reinforcement. Next, he was instructed to engage in the activity under a two-choice fixed-duration…

  13. Reinforcement learning in continuous state and action spaces

    NARCIS (Netherlands)

    Hasselt, H. van; Wiering, M.A.; Otterlo, M. van

    2012-01-01

    Many traditional reinforcement-learning algorithms have been designed for problems with small finite state and action spaces. Learning in such discrete problems can been difficult, due to noise and delayed reinforcements. However, many real-world problems have continuous state or action spaces, whic

  14. The QV Family Compared to Other Reinforcement Learning Algorithms

    NARCIS (Netherlands)

    Wiering, Marco A.; van Hasselt, Hado

    2009-01-01

    This paper describes several new online model-free reinforcement learning (RL) algorithms. We designed three new reinforcement algorithms, namely: QV2, QVMAX, and QV-MAX2, that are all based on the QV-learning algorithm, but in contrary to QV-learning, QVMAX and QVMAX2 are off-policy RL algorithms a

  15. Midbroken Reinforced Concrete Shear Frames Due to Earthquakes

    DEFF Research Database (Denmark)

    Köylüoglu, H. U.; Cakmak, A. S.; Nielsen, Søren R. K.

    A non-linear hysteretic model for the response and local damage analyses of reinforced concrete shear frames subject to earthquake excitation is proposed, and, the model is applied to analyse midbroken reinforced concrete (RC) structures due to earthquake loads. Each storey of the shear frame is...

  16. Self Versus Teacher Selected Reinforcers in a Token Economy

    Science.gov (United States)

    Karraker, R. J.

    1977-01-01

    The rate of achievement and enjoyment of 12 learning disabled pupils (ages 8-12 years) in a token economy was demonstrated to be higher when they were permitted to select their own reinforcers than when the teacher selected the reinforcers. (MH)

  17. Disperse reinforced concrete used in obtaining prefabricated elements for roads

    Directory of Open Access Journals (Sweden)

    Bogdan MEZEI

    2014-07-01

    Full Text Available Concrete is the most used material in construction. By improving the performance of materials and of technologies, concretes with outstanding performances were also developed, in the past two decades. Concrete with dispersed reinforcement represents a new generation of reinforced concrete that combines a good behavior of concrete compressive strength with an increased tensile strength of steel fibers. Using this material, monolithic and prefabricated concrete elements with high mechanical strengths and high durability can be obtained. Technological processes for preparation of concrete with dispersed reinforcement are similar to the conventional methods and do not involve using additional equipment for dosing the dispersed reinforcement. The study aimed the development of road plates made with optimized disperse- reinforced concrete. The first tests were done on plates from the gutter roadway, having a classic reinforcement, using different percentages of fibre reinforcement in the concrete composition, leading to the development of a new optimized economical solution. The results prove the enhanced characteristics of the disperse-reinforced concrete versus conventional concrete, and hence of the developed concrete plates.

  18. Calibration of Partial Factors for Basal Reinforced Piled Embankments

    NARCIS (Netherlands)

    Van Duijnen, P.G.; Schweckendiek, T.; Calle, E.O.F.; Van Eekelen, S.J.M.

    2015-01-01

    In the Netherlands, the design guideline for basal reinforced piled embankments has been revised (CUR226:2015) adopting a new analytical design model (The Concentric Arches (CA) model, Van Eekelen et al., 2013; 2015). The CA model provides geosynthetic reinforcement (GR) strains which were compared

  19. Engineered cementitious composites for strengthening masonry infilled reinforced concrete frames

    DEFF Research Database (Denmark)

    Dehghani, Ayoub; Nateghi-Alahi, Fariborz; Fischer, Gregor

    2015-01-01

    The results of the second part of a comprehensive experimental program, aimed at investigating the behavior of masonry infilled reinforced concrete (RC) frames strengthened with fiber reinforced engineered cementitious composites (ECC) used as an overlay on the masonry wall, are presented in this...

  20. Reinforcement Practices of Black and White Teachers in Integrated Classrooms

    Science.gov (United States)

    Byalick, Robert; Bersoff, Donald N.

    1974-01-01

    The Positive Reinforcement Observation Schedule was used to obtain data concerning expressed preference for and observed use of positive reinforcement in integrated classrooms taught by 30 black and 30 white female elementary school teachers. The results are related to previous research and implications are drawn. (Author/SE)

  1. Covert Operant Reinforcement of Remedial Reading Learning Tasks.

    Science.gov (United States)

    Schmickley, Verne G.

    The effects of covert operant reinforcement upon remedial reading learning tasks were investigated. Forty junior high school students were taught to imagine either neutral scenes (control) or positive scenes (treatment) upon cue while reading. It was hypothesized that positive covert reinforcement would enhance performance on several measures of…

  2. Reinforcement effect of soy protein and carbohydrates in polymer composites

    Science.gov (United States)

    The modulus of soft polymer material can be increased by filler reinforcement. A review of using soy protein and carbohydrates as alternative renewable reinforcement material is presented here. Dry soy protein and carbohydrates are rigid and can form strong filler networks through hydrogen-bonding...

  3. Fiber-reinforced dental composites in beam testing.

    NARCIS (Netherlands)

    Heumen, C.C.M. van; Kreulen, C.M.; Bronkhorst, E.M.; Lesaffre, E.; Creugers, N.H.J.

    2008-01-01

    OBJECTIVES: The purpose of this study was to systematically review current literature on in vitro tests of fiber-reinforced composite (FRC) beams, with regard to studies that followed criteria described in an International Standard. The reported reinforcing effects of various fibers on the flexural

  4. Chemical properties of reinforcing fiberglass in aggressive media

    Directory of Open Access Journals (Sweden)

    Avdeeva Arina

    2016-01-01

    Full Text Available In this article describe reinforced fiberglass. Fiberglass – fiber or complex yarn, formed from glass. The main application area of fiberglass and fiberglass textile materials is their use as reinforcing elements of fiberglass plastics and composites. For its consideration, conducted laboratory tests were conducted. As a result of the research was chosen the best of the characteristics of fiberglass.

  5. Novelty as a Reinforcer for Position Learning in Children

    Science.gov (United States)

    Wilson, Marian Monyok

    1974-01-01

    The stimulus-familiarization-effect (SFE) paradigm, a reaction-time (RT) task based on a response to novelty procedure, was modified to assess response for novelty, ie., a response-reinforcement sequence. The potential implications of attention for reinforcement theory and learning in general are discussed. (Author/CS)

  6. The Effect of Conditioned Reinforcement Rate on Choice: A Review

    Science.gov (United States)

    Fantino, Edmund; Romanowich, Paul

    2007-01-01

    We review the nature of conditioned reinforcement, including evidence that conditioned reinforcers maintain choice behavior in concurrent schedules and that they elevate responding in the terminal links of concurrent-chains schedules. A question has resurfaced recently: Do theories of choice in concurrent-chains schedules need to include a term…

  7. On the Possibility of a Reinforcement Theory of Cognitive Learning.

    Science.gov (United States)

    Smith, Kendon

    This paper discusses cognitive learning in terms of reinforcement theory and presents arguments suggesting that a viable theory of cognition based on reinforcement principles is not out of the question. This position is supported by a discussion of the weaknesses of theories based entirely on contiguity and of considerations that are more positive…

  8. Behavioral Momentum: Implications and Development from Reinforcement Theories.

    Science.gov (United States)

    Plaud, Joseph J.; Gaither, George A.

    1996-01-01

    Analyzes historical and contemporary theories of reinforcement and clinical application of reinforcement principles to behavior and modification therapy. Presents a behavioral momentum model that studies the allocation of behavior under changed environmental constraints and discusses the implications of this model on behavior modification and…

  9. Anchorage of Main Reinforcement in Lightweight Aggregate Concrete Beams

    DEFF Research Database (Denmark)

    Larsen, Henning

    1999-01-01

    The paper deals with the anchorage of reinforcement bars at end supports in beam component made of lightweight aggregate concrete with open structure.......The paper deals with the anchorage of reinforcement bars at end supports in beam component made of lightweight aggregate concrete with open structure....

  10. Reinforced Variability in Animals and People: Implications for Adaptive Action.

    Science.gov (United States)

    Neuringer, Allen

    2004-01-01

    Although reinforcement often leads to repetitive, even stereotyped responding, that is not a necessary outcome. When it depends on variations, reinforcement results in responding that is diverse, novel, indeed unpredictable, with distributions sometimes approaching those of a random process. This article reviews evidence for the powerful and…

  11. Aggression as Positive Reinforcement in People with Intellectual Disabilities

    Science.gov (United States)

    May, Michael E.

    2011-01-01

    From an applied behavior-analytic perspective, aggression in people with intellectual disabilities is mostly maintained by social reinforcement consequences. However, nonsocial consequences have also been identified in functional assessments on aggression. Behaviors producing their own reinforcement have been labeled "automatic" or "nonsocial" in…

  12. Punishment Insensitivity and Impaired Reinforcement Learning in Preschoolers

    Science.gov (United States)

    Briggs-Gowan, Margaret J.; Nichols, Sara R.; Voss, Joel; Zobel, Elvira; Carter, Alice S.; McCarthy, Kimberly J.; Pine, Daniel S.; Blair, James; Wakschlag, Lauren S.

    2014-01-01

    Background: Youth and adults with psychopathic traits display disrupted reinforcement learning. Advances in measurement now enable examination of this association in preschoolers. The current study examines relations between reinforcement learning in preschoolers and parent ratings of reduced responsiveness to socialization, conceptualized as a…

  13. An Investigation of Differential Reinforcement of Alternative Behavior without Extinction

    Science.gov (United States)

    Athens, Elizabeth S.; Vollmer, Timothy R.

    2010-01-01

    We manipulated relative reinforcement for problem behavior and appropriate behavior using differential reinforcement of alternative behavior (DRA) without an extinction component. Seven children with developmental disabilities participated. We manipulated duration (Experiment 1), quality (Experiment 2), delay (Experiment 3), or a combination of…

  14. 14 CFR 25.875 - Reinforcement near propellers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reinforcement near propellers. 25.875 Section 25.875 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION....875 Reinforcement near propellers. (a) Each part of the airplane near the propeller tips must...

  15. Topology Optimization for Conceptual Design of Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Amir, Oded; Bogomolny, Michael

    2011-01-01

    Design of reinforced concrete structures is governed by the nonlinear behavior of concrete and by its dierent strengths in tension and compression. The purpose of this article is to present a computational procedure for optimal conceptual design of reinforced concrete structures, based on topolog...

  16. Online reinforcement learning for dynamic multimedia systems.

    Science.gov (United States)

    Mastronarde, Nicholas; van der Schaar, Mihaela

    2010-02-01

    In our previous work, we proposed a systematic cross-layer framework for dynamic multimedia systems, which allows each layer to make autonomous and foresighted decisions that maximize the system's long-term performance, while meeting the application's real-time delay constraints. The proposed solution solved the cross-layer optimization offline, under the assumption that the multimedia system's probabilistic dynamics were known a priori, by modeling the system as a layered Markov decision process. In practice, however, these dynamics are unknown a priori and, therefore, must be learned online. In this paper, we address this problem by allowing the multimedia system layers to learn, through repeated interactions with each other, to autonomously optimize the system's long-term performance at run-time. The two key challenges in this layered learning setting are: (i) each layer's learning performance is directly impacted by not only its own dynamics, but also by the learning processes of the other layers with which it interacts; and (ii) selecting a learning model that appropriately balances time-complexity (i.e., learning speed) with the multimedia system's limited memory and the multimedia application's real-time delay constraints. We propose two reinforcement learning algorithms for optimizing the system under different design constraints: the first algorithm solves the cross-layer optimization in a centralized manner and the second solves it in a decentralized manner. We analyze both algorithms in terms of their required computation, memory, and interlayer communication overheads. After noting that the proposed reinforcement learning algorithms learn too slowly, we introduce a complementary accelerated learning algorithm that exploits partial knowledge about the system's dynamics in order to dramatically improve the system's performance. In our experiments, we demonstrate that decentralized learning can perform equally as well as centralized learning, while

  17. Finite element analysis of Polymer reinforced CRC columns under close-in detonation

    DEFF Research Database (Denmark)

    Riisgaard, Benjamin

    2007-01-01

    Polymer reinforced Compact Reinforced Composite, PCRC, is a Fiber reinforced Densified Small Particle system, FDSP, combined with a high strength longitudinal flexural rebar arrangement laced together with polymer lacing to avoid shock initiated disintegration of the structural element under blast...

  18. Mechanical properties of rice husk flour reinforced epoxy biocomposite

    Directory of Open Access Journals (Sweden)

    Neeraj Bisht

    2015-06-01

    Full Text Available A bio-composite reinforced with rice husk flour in epoxy resin has been developed. The effect of fibre treatment and weight percentage of rice husk on the mechanical properties was studied and compared with wood dust reinforced epoxy composite. It was observed that addition of rice husk as filler is detrimental to almost all the mechanical properties. About 51% and 26.8% decrease in ultimate strength and Young’s Modulus for 40 wt% untreated rice husk reinforcement was observed. The corresponding decrease in flexural strength and flexural modulus was 51%. Similar trend was also observed in hardness and impact strength. However the mechanical properties of rice husk reinforced biocomposites are found to be superior than wood dust reinforced epoxy composite. SEM microscopy was also done to corroborate the results.

  19. Shear capacity of reinforced concrete columns strengthened with CFRP sheet

    Institute of Scientific and Technical Information of China (English)

    XIE Jian; LIU Xue-mei; ZHAO Tong

    2005-01-01

    This paper discusses the results of tests on the shear capacity of reinforced concrete columns strengthened with carbon fiber reinforced plastic (CFRP) sheet. The shear transfer mechanism of the specimens reinforced with CFRP sheet was studied. The factors affecting the shear capacity of reinforced concrete columns strengthened with CFRP sheet were analyzed. Several suggestions such as the number of layers, width and tensile strength of the CFRP sheet are proposed for this new strengthening technique. Finally, a simple and practical design method is presented in the paper. The calculated results of the suggested method are shown to be in good agreement with the test results. The suggested design method can be used in evaluating the shear capacity of reinforced concrete columns strengthened with CFRP sheet.

  20. Multilayered Glass Fibre-reinforced Composites In Rotational Moulding

    Science.gov (United States)

    Chang, W. C.; Harkin-Jones, E.; Kearns, M.; McCourt, M.

    2011-05-01

    The potential of multiple layer fibre-reinforced mouldings is of growing interest to the rotational moulding industry because of their cost/performance ratio. The particular problem that arises when using reinforcements in this process relate to the fact that the process is low shear and good mixing of resin and reinforcement is not optimum under those conditions. There is also a problem of the larger/heavier reinforcing agents segregating out of the powder to lay up on the inner part surface. In this study, short glass fibres were incorporated and distributed into a polymer matrix to produce fibre-reinforced polymer composites using the rotational moulding process and characterised in terms of morphology and mechanical properties.

  1. Behavior of reinforcement SCC beams under elevated temperatures

    Science.gov (United States)

    Fathi, Hamoon; Farhang, Kianoosh

    2015-09-01

    This experimental study focuses on the behavior of heated reinforced concrete beams. Four types of concrete mixtures were used for the tested self-compacting concrete beams. A total of 72 reinforced concrete beams and 72 standard cylindrical specimens were tested. The compressive strength under uniaxial loading at 23 °C ranged from 30 to 45 MPa. The specimens were exposed to different temperatures. The test parameters of interest were the compressive strength and the temperature of the specimens. The effect of changes in the parameters was examined so as to control the behavior of the tested concrete and that of the reinforced concrete beam. The results indicated that flexibility and compressive strength of the reinforced concrete beams decreased at higher temperatures. Furthermore, heating beyond 400 °C produced greater variations in the structural behavior of the materials in both the cylindrical samples and the reinforced concrete beams.

  2. Mechanism of Reinforcement on Inwall of Coal Mine Shaft Wall

    Directory of Open Access Journals (Sweden)

    Jinlong Liu

    2013-05-01

    Full Text Available Based on the theory of elasticity, the analytic solution of temperature stress on shaft wall of coal mine with reinforcement on inwall is deduced. It is shown that with the increment of reinforcement stress Pa, the radial compressive stress &sigmar become larger, the vertical compressive stress &sigmaz become less, while the circumferential stress &sigma &theta changed from compressive stress to tensile stress. The stability of shaft wall enhanced with vertical stress reduced by reinforcement on inwall of shaft wall. Compressive steel plate could be used to reinforce the inwall, characterized with low-cost, short time and construction easy. While the intelligent equipment should be developed further to provide everlasting and greater reinforcement on in wall of coal mine shaft wall.

  3. Aluminum matrix composites reinforced with alumina nanoparticles

    CERN Document Server

    Casati, Riccardo

    2016-01-01

    This book describes the latest efforts to develop aluminum nanocomposites with enhanced damping and mechanical properties and good workability. The nanocomposites exhibited high strength, improved damping behavior and good ductility, making them suitable for use as wires. Since the production of metal matrix nanocomposites by conventional melting processes is considered extremely problematic (because of the poor wettability of the nanoparticles), different powder metallurgy routes were investigated, including high-energy ball milling and unconventional compaction methods. Special attention was paid to the structural characterization at the micro- and nanoscale, as uniform nanoparticle dispersion in metal matrix is of prime importance. The aluminum nanocomposites displayed an ultrafine microstructure reinforced with alumina nanoparticles produced in situ or added ex situ. The physical, mechanical and functional characteristics of the materials produced were evaluated using different mechanical tests and micros...

  4. Reinforcement Learning for a New Piano Mover

    Directory of Open Access Journals (Sweden)

    Yuko Ishiwaka

    2005-08-01

    Full Text Available We attempt to achieve corporative behavior of autonomous decentralized agents constructed via Q-Learning, which is a type of reinforcement learning. As such, in the present paper, we examine the piano mover's problem. We propose a multi-agent architecture that has a training agent, learning agents and intermediate agent. Learning agents are heterogeneous and can communicate with each other. The movement of an object with three kinds of agent depends on the composition of the actions of the learning agents. By learning its own shape through the learning agents, avoidance of obstacles by the object is expected. We simulate the proposed method in a two-dimensional continuous world. Results obtained in the present investigation reveal the effectiveness of the proposed method.

  5. Challenging or Reinforcing the Gender Divide?

    DEFF Research Database (Denmark)

    Nielsen, Poul Erik; Gustafsson, Jessica

    2016-01-01

    This chapter aims to deepen the understanding of how the appropriations of new communication technologies in dramatic changing communication ecologies interrelate with social and cultural changes in contemporary rural and urban Kenya, focusing on gender and space. The study, which is set in Uasin...... Gishu County, Kenya, is based on a 799 households survey concerning gendered access and usage of media and ICT and 80 life-world interviews with men and women on their appropriations of new media. The chapter concludes that the interrelation between new media and gender is complex. To a large extent the...... media usage reflects the patriarchal structure in Kenya and reinforces gendered spaces but new media also offer new spaces that challenge prevailing norms. Suggesting that new technologies can simultaneously function as vehicles of transformation and reproduce power relations and cultural patterns....

  6. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish the......Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition of...

  7. Real-Time Scheduling via Reinforcement Learning

    CERN Document Server

    Glaubius, Robert; Gill, Christopher; Smart, William D

    2012-01-01

    Cyber-physical systems, such as mobile robots, must respond adaptively to dynamic operating conditions. Effective operation of these systems requires that sensing and actu- ation tasks are performed in a timely manner. Additionally, execution of mission specific tasks such as imaging a room must be bal- anced against the need to perform more gen- eral tasks such as obstacle avoidance. This problem has been addressed by maintaining relative utilization of shared resources among tasks near a user-specified target level. Pro- ducing optimal scheduling strategies requires complete prior knowledge of task behavior, which is unlikely to be available in practice. Instead, suitable scheduling strategies must be learned online through interaction with the system. We consider the sample com- plexity of reinforcement learning in this do- main, and demonstrate that while the prob- lem state space is countably infinite, we may leverage the problem's structure to guarantee efficient learning.

  8. Tendons Arrangement Effects on Reinforced Concrete Frames

    Directory of Open Access Journals (Sweden)

    Ayad B. Bahnam

    2013-05-01

    Full Text Available  The tendons arrangement effects on the response of reinforced concrete frame experiencing blast loads is investigated in this paper. The structure is modeled using nonlinear finite elements employing a bilinear hysteretic model. So that elements are used so that yielding of the structures could be accurately modeled and captured. The frame is analyzed using a non-linear, elastic-plastic finite element program written in code MATLAB. Six tendon architectures were investigated. A single tendon was placed between different floors and its effects investigated. From the obtained results, the ideal case which causes a reduction in the maximum displacement and the amount of permanent deflection without increase in the maximum structural shear forces greatly is obtained.

  9. Micromechanical failure in fiber-reinforced composites

    DEFF Research Database (Denmark)

    Ashouri Vajari, Danial

    Micromechanical failure mechanisms occurring in unidirectional fiber-reinforced composites are studied by means of the finite element method as well as experimental testing. This study highlights the effect of micro-scale features such as fiber/matrix interfacial debonding, matrix cracking and...... microvoids on the microscopic and macroscopic mechanical response of composite materials. To this end, first a numerical study is carried out to explore ways to stabilize interfacial crack growth under dominant Mode-I fracture using the cohesive zone model. Consequently, this study suggests a method to...... composites. In the first approach, the J2 plasticity model is implemented to model the elasto-plastic behavior of the matrix while in the second strategy the modified Drucker-Prager plasticity model is utilized to account for brittle-like and pressure dependent behavior of an epoxy matrix. In addition, the...

  10. Analysis of composite car bumper reinforcement

    Directory of Open Access Journals (Sweden)

    Kleisner V.

    2009-12-01

    Full Text Available The presented work summarizes the present state of car passive safety testing according to European methodologies. The main objective is to analysis a bumper reinforcement made of composite materials. The bumper is tested according to RCAR (Research Council for Automobile Repairs methodology using numerical simulation. Individual proposed variants are compared with the existing steel construction which does not comply with manufacturers specifications. The PAM-Crash software is used for the simulation. The numerical model is using shell elements and the Ladevèze model for the description of behaviour of composite materials. The methodology for the set-up of the numerical model in PAM-crash is firstly validated by comparison of experiment and analytical results.

  11. Continuous fiber-reinforced titanium aluminide composites

    Science.gov (United States)

    Mackay, R. A.; Brindley, P. K.; Froes, F. H.

    1991-01-01

    An account is given of the fabrication techniques, microstructural characteristics, and mechanical behavior of a lightweight, high service temperature SiC-reinforced alpha-2 Ti-14Al-21Nb intermetallic-matrix composite. Fabrication techniques under investigation to improve the low-temperature ductility and environmental resistance of this material system, while reducing manufacturing costs to competitive levels, encompass powder-cloth processing, foil-fiber-foil processing, and thermal-spray processing. Attention is given to composite microstructure problems associated with fiber distribution and fiber-matrix interfaces, as well as with mismatches of thermal-expansion coefficient; major improvements are noted to be required in tensile properties, thermal cycling effects, mechanical damage, creep, and environmental effects.

  12. Reinforced aluminium conductor for cryogenic applications

    International Nuclear Information System (INIS)

    Extreme purity aluminum has very attractive electrical properties at temperatures below 25 K which makes it competitive with conventional superconductors for cryogenic applications. Besides its inherently low density, its resistivity decreases by several orders of magnitude over its room temperature value thus making it suitable for use in lightweight high current density devices. This paper describes the fabrication of a 99.999% aluminum conductor reinforced by a powder metallurgy (P/M) processed Al-Fe-Ce alloy. Long continuous lengths of composite conductors consisting of 1, 4 and 19 Al filaments have been produced by streamline die hot extrusion and cold working by conventional wire drawing or cold hydrostatic extrusion. Microstructural observations and some limited electrical resistivity and mechanical property data are presented along with an analysis of the contamination of high purity Al conductors by diffusion during annealing

  13. Contributions to reinforced concrete structures numerical simulations

    International Nuclear Information System (INIS)

    In order to be able to carry out simulations of reinforced concrete structures, it is necessary to know two aspects: the behaviour laws have to reflect the complex behaviour of concrete and a numerical environment has to be developed in order to avoid to the user difficulties due to the softening nature of the behaviour. This work deals with these two subjects. After an accurate estimation of two behaviour models (micro-plan and mesoscopic models), two damage models (the first one using a scalar variable, the other one a tensorial damage of the 2 order) are proposed. These two models belong to the framework of generalized standard materials, which renders their numerical integration easy and efficient. A method of load control is developed in order to make easier the convergence of the calculations. At last, simulations of industrial structures illustrate the efficiency of the method. (O.M.)

  14. Optimal Reinforcement Learning for Gaussian Systems

    CERN Document Server

    Hennig, Philipp

    2011-01-01

    The exploration-exploitation tradeoff is among the central challenges of reinforcement learning. A hypothetical exact Bayesian learner would provide the optimal solution, but is intractable in general. I show that, however, in the specific case of Gaussian process inference, it is possible to make analytic statements about optimal learning of both rewards and transition dynamics, for nonlinear, time-varying systems in continuous time and space, subject to a relatively weak restriction on the dynamics. The solution is described by an infinite-dimensional differential equation. For a first impression of how this result may be useful, I also provide an approximate reduction to a finite-dimensional problem, with a numeric solution.

  15. Democratic reinforcement: A principle for brain function

    International Nuclear Information System (INIS)

    We introduce a simple ''toy'' brain model. The model consists of a set of randomly connected, or layered integrate-and-fire neurons. Inputs to and outputs from the environment are connected randomly to subsets of neurons. The connections between firing neurons are strengthened or weakened according to whether the action was successful or not. Unlike previous reinforcement learning algorithms, the feedback from the environment is democratic: it affects all neurons in the same way, irrespective of their position in the network and independent of the output signal. Thus no unrealistic back propagation or other external computation is needed. This is accomplished by a global threshold regulation which allows the system to self-organize into a highly susceptible, possibly ''critical'' state with low activity and sparse connections between firing neurons. The low activity permits memory in quiescent areas to be conserved since only firing neurons are modified when new information is being taught

  16. Ductility of high strength reinforced concrete columns

    International Nuclear Information System (INIS)

    Based on the experimental research of 48 reinforced concrete columns using high strength and normal strength concrete under monotonic and cyclic loading, the factors which affect the ductility, such as the concrete strength, axial load ratio, stirrup volume ratio, etc., are analyzed. It can be concluded that the axial load ratio is the most important factor that affects the ductility. The axial load ratio limits and relative stirrup volume ratio limits were proposed under the condition of limited ductility (μΔ≥3). The experiments also show that the relationship between the stirrup ratio and axial load ratio is not linear if the axial load ratio is high, which is different from the finding of previous research. In the design, a simplified bilinear relationship can be adopted which agrees well with the experimental results. (orig.)

  17. Durable fiber reinforced self-compacting concrete

    International Nuclear Information System (INIS)

    In order to produce thin precast elements, a self-compacting concrete was prepared. When manufacturing these elements, homogenously dispersed steel fibers instead of ordinary steel-reinforcing mesh were added to the concrete mixture at a dosage of 10% by mass of cement. An adequate concrete strength class was achieved with a water to cement ratio of 0.40. Compression and flexure tests were carried out to assess the safety of these thin concrete elements. Moreover, serviceability aspects were taken into consideration. Firstly, drying shrinkage tests were carried out in order to evaluate the contribution of steel fibers in counteracting the high concrete strains due to a low aggregate-cement ratio. Secondly, the resistance to freezing and thawing cycles was investigated on concrete specimens in some cases superficially treated with a hydrophobic agent. Lastly, both carbonation and chloride penetration tests were carried out to assess durability behavior of this concrete mixture

  18. Reinforced plastics and aerogels by nanocrystalline cellulose

    International Nuclear Information System (INIS)

    Nanocrystalline cellulose (NCC), a rigid rod-like nanoscale material, can be produced from cellulosic biomass in powder, liquid, or gel forms by acid and chemical hydrolysis. Owing to its unique and exceptional physicochemical properties, the incorporation of a small amount of NCC into plastic enhances the mechanical strength of the latter by several orders of magnitudes. Carbohydrate-based NCC poses no serious environmental concerns, providing further impetus for the development and applications of this green and renewable biomaterial to fabricate lightweight and biodegradable composites and aerogels. Surface functionalization of NCC remains the main focus of NCC research to tailor its properties for dispersion in hydrophilic or hydrophobic media. It is of uttermost importance to develop tools and protocols for imaging of NCC in a complex matrix and quantify its reinforcement effect.

  19. Composites reinforcement by rods: a SAS study

    International Nuclear Information System (INIS)

    The mechanical properties of composites are governed by size, shape and dispersion degree of so-called reinforcing particles. Polymeric fillers based on thermodynamically driven microphase separation of block copolymers offer the opportunity to study a model system of controlled rod-like filler particles. We chose a triblock copolymer (PBPSPB) and carried out SAS measurements with both X-rays and neutrons, in order to characterize separately the hard phase and the cross-linked PB matrix. The properties of the material depend strongly on the way that stress is carried and transferred between the soft matrix and the hard fibers. The failure of the strain-amplification concept and the change of topological contributions to the free energy and scattering factor have to be addressed. In this respect the composite shows a similarity to a two-network system, i.e. interpenetrating rubber and rod-like filler networks. (orig.)

  20. Buckling and Vibration of Fiber Reinforced Composite Plates With Nanofiber Reinforced Matrices

    Science.gov (United States)

    Chamis, Christos C.; Murthy, Pappu L. N.

    2011-01-01

    Anisotropic composite plates were evaluated with nanofiber reinforced matrices (NFRM). The nanofiber reinforcement volumes ratio in the matrix was 0.01. The plate dimensions were 20 by 10 by 1.0 in. (508 by 254 by 25.4 mm). Seven different loading condition cases were evaluated for buckling: three for uniaxial loading, three for pairs of combined loading, and one with three combined loadings. The anisotropy arose from the unidirectional plates having been at 30 from the structural axis. The anisotropy had a full 6 by 6 rigidities matrix which were satisfied and solved by a Galerkin buckling algorithm. For vibration the same conditions were used with the applied cods about a small fraction of the buckling loads. The buckling and vibration results showed that the NFRM plates buckled at about twice those with conventional matrix.

  1. The Experimental Study of Concrete Beams Reinforced with Different Types of Bars Carrying Capacity

    OpenAIRE

    Benin Andrey; Semenov Sergey; Ekaterina Bogdanova

    2016-01-01

    The results of experimental study on concrete beams reinforced with glass fiber reinforced plastic (GFRP) bars are presented and compared with steel reinforced concrete beams and beams reinforced with steel and GFRP bars together. Three series of reinforced beams were tested in the flexure. The experimental data are showed that possible area in which GFRP bar possesses potential to employ is secondary reinforcement in concrete structures.

  2. Choices between positive and negative reinforcement during treatment for escape-maintained behavior.

    OpenAIRE

    DeLeon, I G; Neidert, P L; Anders, B M; Rodriguez-Catter, V

    2001-01-01

    Positive reinforcement was more effective than negative reinforcement in promoting compliance and reducing escape-maintained problem behavior for a child with autism. Escape extinction was then added while the child was given a choice between positive or negative reinforcement for compliance and the reinforcement schedule was thinned. When the reinforcement requirement reached 10 consecutive tasks, the treatment effects became inconsistent and reinforcer selection shifted from a strong prefer...

  3. Generating Variable and Random Schedules of Reinforcement Using Microsoft Excel Macros

    OpenAIRE

    Bancroft, Stacie L; Bourret, Jason C

    2008-01-01

    Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time. Generating schedule values for variable and random reinforcement schedules can be difficult. The present article describes the steps necessary to writ...

  4. Multiagent reinforcement learning with unshared value functions.

    Science.gov (United States)

    Hu, Yujing; Gao, Yang; An, Bo

    2015-04-01

    One important approach of multiagent reinforcement learning (MARL) is equilibrium-based MARL, which is a combination of reinforcement learning and game theory. Most existing algorithms involve computationally expensive calculation of mixed strategy equilibria and require agents to replicate the other agents' value functions for equilibrium computing in each state. This is unrealistic since agents may not be willing to share such information due to privacy or safety concerns. This paper aims to develop novel and efficient MARL algorithms without the need for agents to share value functions. First, we adopt pure strategy equilibrium solution concepts instead of mixed strategy equilibria given that a mixed strategy equilibrium is often computationally expensive. In this paper, three types of pure strategy profiles are utilized as equilibrium solution concepts: pure strategy Nash equilibrium, equilibrium-dominating strategy profile, and nonstrict equilibrium-dominating strategy profile. The latter two solution concepts are strategy profiles from which agents can gain higher payoffs than one or more pure strategy Nash equilibria. Theoretical analysis shows that these strategy profiles are symmetric meta equilibria. Second, we propose a multistep negotiation process for finding pure strategy equilibria since value functions are not shared among agents. By putting these together, we propose a novel MARL algorithm called negotiation-based Q-learning (NegoQ). Experiments are first conducted in grid-world games, which are widely used to evaluate MARL algorithms. In these games, NegoQ learns equilibrium policies and runs significantly faster than existing MARL algorithms (correlated Q-learning and Nash Q-learning). Surprisingly, we find that NegoQ also performs well in team Markov games such as pursuit games, as compared with team-task-oriented MARL algorithms (such as friend Q-learning and distributed Q-learning). PMID:25014990

  5. A Comparison of Differential Reinforcement and Noncontingent Reinforcement to Treat Food Selectivity in a Child with Autism

    Science.gov (United States)

    Allison, Janelle; Wilder, David A.; Chong, Ivy; Lugo, Ashley; Pike, Jessica; Rudy, Nikki

    2012-01-01

    We compared differential reinforcement plus escape extinction to noncontingent reinforcement plus escape extinction to treat food selectivity exhibited by a young child with autism. The interventions were equally effective for increasing bite acceptance and decreasing problem behaviors. However, a social validity measure suggested that…

  6. Behaviour of fibre reinforced polymer confined reinforced concrete columns under fire condition

    Science.gov (United States)

    Chowdhury, Ershad Ullah

    In recent years, fibre reinforced polymer (FRP) materials have demonstrated enormous potential as materials for repairing and retrofitting concrete bridges that have deteriorated from factors such as electro-chemical corrosion and increased load requirements. However, concerns associated with fire remain an obstacle to applications of FRP materials in buildings and parking garages due to FRP's sensitivity to high temperatures as compared with other structural materials and to limited knowledge on their thermal and mechanical behaviour in fire. This thesis presents results from an ongoing study on the fire performance of FRP materials, fire insulation materials and systems, and FRP wrapped reinforced concrete columns. The overall goal of the study is to understand the fire behaviour of FRP materials and FRP strengthened concrete columns and ultimately, provide rational fire safety design recommendations and guidelines for FRP strengthened concrete columns. A combined experimental and numerical investigation was conducted to achieve the goals of this research study. The experimental work consisted of both small-scale FRP material testing at elevated temperatures and full-scale fire tests on FRP strengthened columns. A numerical model was developed to simulate the behaviour of unwrapped reinforced concrete and FRP strengthened reinforced concrete square or rectangular columns in fire. After validating the numerical model against test data available in literature, it was determined that the numerical model can be used to analyze the behaviour of concrete axial compressive members in fire. Results from this study also demonstrated that although FRP materials experience considerable loss of their mechanical and bond properties at temperatures somewhat below the glass transition temperature of the resin matrix, externally-bonded FRP can be used in strengthening concrete structural members in buildings, if appropriate supplemental fire protection system is provided over

  7. Strengthening of two-way reinforced concrete slabs with Textile Reinforced Mortars (TRM)

    OpenAIRE

    Papanicolaou, Catherine; Triantafillou, Thanasis; Papantoniou, Ioannis; Balioukos, Christos

    2009-01-01

    An innovative strengthening technique is applied for the first time in this study to provide flexural strengthening in two-way reinforced concrete (RC) slabs supported on edge beams. The technique comprises external bonding of textiles on the tension face of RC slabs through the use of polymer-modified cement- based mortars. The textiles used in the experimental campaign comprised fabric meshes made of long stitch-bonded fibre rovings in two orthogonal directions. The specimens measured 2 x 2...

  8. Shear strengthening of pre-damaged reinforced concrete beams with carbon fiber reinforced polymer sheet strips

    Institute of Scientific and Technical Information of China (English)

    Feras ALZOUBI; ZHANG Qi; LI Zheng-liang

    2007-01-01

    This paper presents the results of an experimental investigation on the response of pre-damaged reinforced concrete (RC) beam strengthened in shear using applied-epoxy unidirectional carbon fiber reinforced polymer (CFRP) sheet. The reasearch included four test rectangular simply supported RC beams in shear capacity. One is the control beam, two RC beams are damaged to a predetermined degree from ultimate shear capacity of the control beam, and the last beam is left without pre-damaged and then strengthened with using externally bonded carbon fiber reinforced polymer to upgrade their shear capacity. We focused on the damage degree to beams during strengthening, therefore, only the beams with side-bonded CFRPs strips and horizontal anchored strips were used. The results show the feasibility of using CFRPs to restore or increase the load-carrying capacity in the shear of damaged RC beams. The failure mode of all the CFRP-strengthened beams is debonding of CFRP vertical strips. Two prediction available models in ACI-440 and fib European code were compared with the experimental results.

  9. Strengthening of Corrosion-Damaged Reinforced Concrete Beams with Glass Fiber Reinforced Polymer Laminates

    Directory of Open Access Journals (Sweden)

    A. L. Rose

    2009-01-01

    Full Text Available Problem statement: This study showed the results of an experimental investigation on the strengthening of corrosion damaged reinforced concrete beams with unidirectional cloth glass fiber reinforced polymer (UDCGFRP laminates. Approach: All the beam specimens 150×250×3000 mm were cast and tested for the present investigation. One beam specimen was neither corroded nor strengthened to serve as a reference. Two beams were corroded to serve as a corroded control. A reinforcement mass loss of approximately 10 and 25% were used to define medium and severe degrees of corrosion. The remaining two beams corroded and strengthened with GFRP. Results: The test parameters included first crack load, first crack deflection, yield load, yield deflection, service load, service deflection, ultimate load and ultimate deflection. Based on the results it was found that GFRP Laminates had beneficial effects even at the corrosion-damaged stage. Conclusion/Recommendations: The UDCGFRP laminated beams showed distinct enhancement in ultimate strength and ductility by 72.37 and 49.49% respectively.

  10. Olfactory preference conditioning changes the reward value of reinforced and non-reinforced odors

    Directory of Open Access Journals (Sweden)

    Nicolas eTorquet

    2014-07-01

    Full Text Available Olfaction is a determinant for the organization of rodent behavior. In a feeding context, rodents must quickly discriminate whether a nutrient can be ingested or whether it represents a potential danger to them. To understand the learning processes that support food choice, aversive olfactory learning and flavor appetitive learning have been extensively studied. In contrast, little is currently known about olfactory appetitive learning and its mechanisms. We designed a new paradigm to study conditioned olfactory preference in rats. After 8 days of exposure to a pair of odors (one paired with sucrose and the other with water, rats developed a strong and stable preference for the odor associated with the sucrose solution. A series of experiments were conducted to further analyze changes in reward value induced by this paradigm for both stimuli. As expected, the reward value of the reinforced odor changed positively. Interestingly, the reward value of the alternative odor decreased. This devaluation had an impact on further odor comparisons that the animal had to make. This result suggests that appetitive conditioning involving a comparison between two odors not only leads to a change in the reward value of the reinforced odor, but also induces a stable devaluation of the non-reinforced stimulus.

  11. Olfactory preference conditioning changes the reward value of reinforced and non-reinforced odors

    Science.gov (United States)

    Torquet, Nicolas; Aimé, Pascaline; Messaoudi, Belkacem; Garcia, Samuel; Ey, Elodie; Gervais, Rémi; Julliard, A. Karyn; Ravel, Nadine

    2014-01-01

    Olfaction is determinant for the organization of rodent behavior. In a feeding context, rodents must quickly discriminate whether a nutrient can be ingested or whether it represents a potential danger to them. To understand the learning processes that support food choice, aversive olfactory learning and flavor appetitive learning have been extensively studied. In contrast, little is currently known about olfactory appetitive learning and its mechanisms. We designed a new paradigm to study conditioned olfactory preference in rats. After 8 days of exposure to a pair of odors (one paired with sucrose and the other with water), rats developed a strong and stable preference for the odor associated with the sucrose solution. A series of experiments were conducted to further analyze changes in reward value induced by this paradigm for both stimuli. As expected, the reward value of the reinforced odor changed positively. Interestingly, the reward value of the alternative odor decreased. This devaluation had an impact on further odor comparisons that the animal had to make. This result suggests that appetitive conditioning involving a comparison between two odors not only leads to a change in the reward value of the reinforced odor, but also induces a stable devaluation of the non-reinforced stimulus. PMID:25071486

  12. Reinforced concrete beams strengthened with carbon fiber reinforced polymer by friction hybrid bond technique: Experimental investigation

    International Nuclear Information System (INIS)

    Highlights: • Friction Hybrid Bonded FRP Technique is conducted to strengthen RC beams. • Six specimens with different reinforced methods were tested. • The strengthened effects of different strengthening methods were discussed. • The results obtained from the FEA and experiments are agreed very well. - Abstract: Carbon fiber reinforced polymer (CFRP) can be used to strengthen the reinforced concrete (RC) beams. But premature debonding is the main failure model in ordinary bond technique, and the strengthening effect is limited. In order to improve bonding and restricting sliding displacement, Friction Hybrid Bonded FRP Technique (FHB-FRP) is developed. Six simple-span RC specimen beams with different strengthened methods were tested in four-point bending. The experiment results indicate that FRP debonding can be effectively prevented by the FHB-FRP strengthened beam. The ultimate load-carrying capacity of the specimen strengthened by FHB-FRP technique is able to increase by a factor of 2.13 times compared with the beam strengthened with ordinary bond technique (U-jacketing technique). In addition, the cracking and yielding loads are improved more significantly by FHB-FRP technique than U-jacketing technique. Specimens strengthened with FHB-FRP technique have cracks with a more limited distribution and width. Finally, the finite element method (FEM) is conducted to simulate the behavior of the test specimens. The results obtained from the finite element method are compared with experiment. Excellent agreements have been achieved in the comparison of results

  13. Experimental and analytical investigation of reinforced high strength concrete continuous beams strengthened with fiber reinforced polymer

    International Nuclear Information System (INIS)

    Carbon and glass fiber reinforced polymer (CFRP and GFRP) are two materials suitable for strengthening the reinforced concrete (RC) beams. Although many in situ RC beams are of continuous constructions, there has been very limited research on the behavior of such beams with externally applied FRP laminate. In addition, most design guidelines were developed for simply supported beams with external FRP laminates. This paper presents an experimental program conducted to study the flexural behavior and redistribution in moment of reinforced high strength concrete (RHSC) continuous beams strengthened with CFRP and GFRP sheets. Test results showed that with increasing the number of CFRP sheet layers, the ultimate strength increases, while the ductility, moment redistribution, and ultimate strain of CFRP sheet decrease. Also, by using the GFRP sheet in strengthening the continuous beam reduced loss in ductility and moment redistribution but it did not significantly increase ultimate strength of beam. The moment enhancement ratio of the strengthened continuous beams was significantly higher than the ultimate load enhancement ratio in the same beam. An analytical model for moment-curvature and load capacity are developed and used for the tested continuous beams in current and other similar studies. The stress-strain curves of concrete, steel and FRP were considered as integrity model. Stress-strain model of concrete is extended from Oztekin et al.'s model by modifying the ultimate strain. Also, new parameters of equivalent stress block are obtained for flexural calculation of RHSC beams. Good agreement between experiment and prediction values is achieved.

  14. Electrospun magnetic nanofibre mats – A new bondable biomaterial using remotely activated magnetic heating

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yi [Department of Materials Engineering, University of British Columbia, Vancouver (Canada); Key Laboratory of Science & Technology of Eco-Textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai (China); Leung, Victor; Yuqin Wan, Lynn [Department of Materials Engineering, University of British Columbia, Vancouver (Canada); Dutz, Silvio [Institut für Biomedizinische Technik und Informatik, Technische Universität Ilmenau (Germany); Department of Nano Biophotonics, Leibniz Institute of Photonic Technology, Jena (Germany); Ko, Frank K., E-mail: frank.ko@ubc.ca [Department of Materials Engineering, University of British Columbia, Vancouver (Canada); Häfeli, Urs O., E-mail: urs.hafeli@ubc.ca [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver (Canada)

    2015-04-15

    A solvothermal process was adopted to produce hydrophilic magnetite (Fe{sub 3}O{sub 4}) nanoparticles which were subsequently emulsified with a chloroform/methanol (70/30 v/v) solution of poly(caprolactone) (PCL) and then electrospun into a 0.2 mm thick PCL mat. The magnetic heating of the mats at a field amplitude of 25 kA/m and frequency of 400 kHz exhibited promising efficiency for magnetic hyperthermia, with a specific absorption rate of about 40 W/g for the magnetic mat. The produced heat was used to melt the magnetic mat onto the surrounding non-magnetic polymer mat from within, without destroying the nanostructure of the non-magnetic polymer more than 0.5 mm away. Magnetic nanofibre mats might thus be useful for internal heat sealing applications, and potentially also for thermotherapy.

  15. Electrospun magnetic nanofibre mats - A new bondable biomaterial using remotely activated magnetic heating

    Science.gov (United States)

    Zhong, Yi; Leung, Victor; Yuqin Wan, Lynn; Dutz, Silvio; Ko, Frank K.; Häfeli, Urs O.

    2015-04-01

    A solvothermal process was adopted to produce hydrophilic magnetite (Fe3O4) nanoparticles which were subsequently emulsified with a chloroform/methanol (70/30 v/v) solution of poly(caprolactone) (PCL) and then electrospun into a 0.2 mm thick PCL mat. The magnetic heating of the mats at a field amplitude of 25 kA/m and frequency of 400 kHz exhibited promising efficiency for magnetic hyperthermia, with a specific absorption rate of about 40 W/g for the magnetic mat. The produced heat was used to melt the magnetic mat onto the surrounding non-magnetic polymer mat from within, without destroying the nanostructure of the non-magnetic polymer more than 0.5 mm away. Magnetic nanofibre mats might thus be useful for internal heat sealing applications, and potentially also for thermotherapy.

  16. Electrospun magnetic nanofibre mats – A new bondable biomaterial using remotely activated magnetic heating

    International Nuclear Information System (INIS)

    A solvothermal process was adopted to produce hydrophilic magnetite (Fe3O4) nanoparticles which were subsequently emulsified with a chloroform/methanol (70/30 v/v) solution of poly(caprolactone) (PCL) and then electrospun into a 0.2 mm thick PCL mat. The magnetic heating of the mats at a field amplitude of 25 kA/m and frequency of 400 kHz exhibited promising efficiency for magnetic hyperthermia, with a specific absorption rate of about 40 W/g for the magnetic mat. The produced heat was used to melt the magnetic mat onto the surrounding non-magnetic polymer mat from within, without destroying the nanostructure of the non-magnetic polymer more than 0.5 mm away. Magnetic nanofibre mats might thus be useful for internal heat sealing applications, and potentially also for thermotherapy

  17. Development and Properties of Glass Fiber Reinforced Plastics Geogrid

    Institute of Scientific and Technical Information of China (English)

    WANG Qingbiao; ZHANG Cong; WEN Xiaokang; L Rongshan; LIANG Xunmei; LU Shide

    2015-01-01

    Glassfi ber reinforced plastics geogrid has a wide application in thefi eld of soil reinforcement because of its high strength, good toughness, and resistance to environmental stress, creep resistance and strong stability. In order to get high-powered glassfi ber reinforced plastics geogrid and its mechanical characteristics, the properties and physical mechanical index of geogrid have been got through the study of its raw material, production process and important quality index. The analysis and study have been made to the geogrid’s mechanical properties with loading speed, three-axial compression, temperature tensile test and FLAC3D numerical simulation, thus obtain the mechanical parameters of its displacement time curve, breaking strength and elongation at break. Some conclusions can be drawn as follows: (a) Using glassfi ber materials, knurling and coated projection process, the fracture strength and corrosion resistance of geogrid are greatly improved and the interlocking bite capability of soil is enhanced. (b) The fracture strength of geogrid is related to temperature and loading rate. When the surrounding rock pressure is fixed, the strength and anti-deformation ability of reinforced soil are significantly enhanced with increasing reinforced layers. (c) The pullout test shows the positive correlation between geogrid displacement and action time. (d) As a new reinforced material, the glass fi ber reinforced plastics geogrid is not mature enough in theoretical research and practical experience, so it has become an urgent problem both in theoretical study and practical innovation.

  18. Thermomechanical analyses of phenolic foam reinforced with glass fiber mat

    International Nuclear Information System (INIS)

    Highlights: • Over 10% glass fiber was used to reinforce phenolic foam in the shape of glass fiber mat. • Nucleating agents were used together with glass fiber mat and improved tensile strength of phenolic foam by 215.6%. • Nucleating agents lead to a smaller bubble size of phenolic foam. • The glass transition temperature of phenolic foam remained unchanged during the reinforcement. - Abstract: In this paper, thermomechanical analysis (TMA) and dynamic mechanical analysis were employed to study the properties of phenolic foam reinforced with glass fiber mat. Unreinforced phenolic foam was taken as the control sample. Mechanical tests and scanning electron microscopy were performed to confirm the results of TMA. The results show that glass fiber mat reinforcement improves the mechanical performance of phenolic foam, and nucleating agents improve it further. Phenolic foam reinforced with glass fiber mat has a smaller thermal expansion coefficient compared with unreinforced foam. The storage modulus of the reinforced phenolic foam is also higher than that in unreinforced foam, whereas the loss modulus of the former is lower than that of the latter. The glass transition temperature of the phenolic foam matrix remains unchanged during the reinforcement

  19. Large-scale direct shear testing of geocell reinforced soil

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The tests on the shear property of geocell reinforced soils were carried out by using large-scale direct shear equipment with shear-box-dimensions of 500 mm×500 mm×400 mm (length×width×height).Three types of specimens,silty gravel soil,geoceli reinforced silty gravel soil and geoceli reinforood cement stabilizing silty gravel soil were used to investigate the shear stress-displacement behavior,the shear strength and the strengthening mechanism of geocell reinforced soils.The comparisons of large-scale shear test with triaxial compression test for the same type of soil were conducted to evaluate the influences of testing method on the shear strength as well.The test results show that the unreinforced soil and geocell reinforced soil give similar nonlinear features on the behavior of shear stress and displacement.The geocell reinforced cement stabilizing soil has a quasi-elastic characteristic in the case of normal stress coming up to 1.0 GPa.The tests with the reinforcement of geocell result in an increase of 244% in cohesion,and the tests with the geocell and the cement stabilization result in an increase of 10 times in cohesion compared with the unreinforced soil.The friction angle does not change markedly.The geocell reinforcement develops a large amount of cohesion on the shear strength of soils.

  20. Mechanical Properties of Welded Deformed Reinforcing Steel Bars

    Directory of Open Access Journals (Sweden)

    Ghafur H. Ahmed

    2015-05-01

    Full Text Available Reinforcement strength, ductility and bendability properties are important components in design of reinforced concrete members, as the strength of any member comes mainly from reinforcement. Strain compatibility and plastic behaviors are mainly depending on reinforcement ductility. In construction practice, often welding of the bars is required. Welding of reinforcement is an instant solution in many cases, whereas welding is not a routine connection process. Welding will cause deficiencies in reinforcement bars, metallurgical changes and re-crystallization of microstructure of particles. Weld metal toughness is extremely sensitive to the welding heat input that decreases both of its strength and ductility. For determining the effects of welding in reinforcement properties, 48 specimens were tested with 5 different bar diameters, divided into six groups. Investigated parameters were: properties of un-welded bars; strength, ductility and density of weld metal; strength and ductility reduction due to heat input for bundled bars and transverse bars; welding effect on bars’ bending properties; behavior of different joint types; properties of three weld groove shapes also the locations and types of failures sections. Results show that, strength and elongation of the welded bars decreased by (10-40% and (30-60% respectively. Cold bending of welded bars and groove welds shall be prevented.