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Sample records for reinforced soil retaining

  1. Calcium Stabilized And Geogrid Reinforced Soil Structures In Seismic Areas

    SciTech Connect

    Rimoldi, Pietro; Intra, Edoardo

    2008-07-08

    In many areas of Italy, and particularly in high seismic areas, there is no or very little availability of granular soils: hence embankments and retaining structures are often built using the locally available fine soil. For improving the geotechnical characteristics of such soils and/or for building steep faced structures, there are three possible techniques: calcium stabilization, geogrid reinforcement, and the combination of both ones, that is calcium stabilized and reinforced soil. The present paper aims to evaluate these three techniques in terms of performance, design and construction, by carrying out FEM modeling and stability analyses of the same reference embankments, made up of soil improved with each one of the three techniques, both in static and dynamic conditions. Finally two case histories are illustrated, showing the practical application of the above outlined techniques.

  2. Root reinforcement of soils under compression

    NASA Astrophysics Data System (ADS)

    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.

  3. Analytical and experimental investigation of soil reinforcing

    NASA Astrophysics Data System (ADS)

    Holtz, R. D.; Harr, M. E.

    1983-10-01

    Significant improvements in the capacity and service life of reinforced earth structures require an improved understanding of the fundamental behavior of these systems. Both experimental and analytical investigations were carried out to develop models for the interaction of geotextile-type reinforcement and granular soils. Reinforcement configurations and systems investigated were thought to be applicable to alternate launch and recovery surfaces (ALRS). Model ALRS systems using geotextiles and geogrids as reinforcement were tested in the laboratory in a variety of configurations. These were loaded to failure, quasi-statically, by both plane strain and axisymmetric rigid plates. Load-deformation characteristics as well as the shape of the deflected basin are reported. Significant increases in bearing capacity and modulus of subgrade reaction as a function of depth and number of layers of reinforcement were observed. However, there was a decrease in improvement as the depth to the first layer increased. Edge fixity conditions were found to be relatively unimportant, and the benefit of multiple-reinforcement layers was greater if the depth and spacing were small compared to the diameter of the loaded area. Surprisingly, little difference was observed in the response of the geogrids and geotextiles, probably because sand was used in the experiments. Geometric scaling of bearing capacity, based on the diameters of the loaded areas, was not possible.

  4. Analysis of Different Positions of Fiber-Reinforced Composite Retainers versus Multistrand Wire Retainers Using the Finite Element Method

    PubMed Central

    Jahanbin, Arezoo; Abtahi, Mostafa; Heravi, Farzin; Hoseini, Mohsen

    2014-01-01

    Background. The aim of this study was to evaluate root displacement of the lower incisors fixed with FRC in different positions versus FSW retainers using the finite element method. Materials and Methods. 3D finite element models were designed for a mandibular anterior segment: Model 1: flexible spiral wire bonded to the lingual teeth surfaces, Model 2: FRC bonded to the upper third of lingual teeth surfaces, and Model 3: FRC bonded to the middle third. FE analysis was performed for three models and then tooth displacements were evaluated. Results. In contrast to lateral incisors and canines, the FSW retainer caused the central teeth to move more than the teeth bonded with FRC in both loadings. Comparison between Models 2 and 3 (in vertical loading) showed that FRC retainers that bonded at the upper third of lingual teeth surfaces made central and canine teeth move less than FRC retainers bonded at the middle third; however, for lateral teeth it was the opposite. Conclusion. FRC retainers bonded at the upper third of lingual teeth surfaces make central and canine teeth move less than FRC retainers bonded at the middle third in vertical loading; however, for lateral teeth it was the opposite. PMID:25400664

  5. Two-year survival analysis of twisted wire fixed retainer versus spiral wire and fiber-reinforced composite retainers: a preliminary explorative single-blind randomized clinical trial

    PubMed Central

    Sobouti, Farhad; Rakhshan, Vahid; Saravi, Mahdi Gholamrezaei; Zamanian, Ali

    2016-01-01

    Objective Traditional retainers (both metal and fiber-reinforced composite [FRC]) have limitations, and a retainer made from more flexible ligature wires might be advantageous. We aimed to compare an experimental design with two traditional retainers. Methods In this prospective preliminary clinical trial, 150 post-treatment patients were enrolled and randomly divided into three groups of 50 patients each to receive mandibular canine-to-canine retainers made of FRC, flexible spiral wire (FSW), and twisted wire (TW). The patients were monitored monthly. The time at which the first signs of breakage/debonding were detected was recorded. The success rates of the retainers were compared using chi-squared, Kaplan-Meier, and Cox proportional-hazard regression analyses (α = 0.05). Results In total, 42 patients in the FRC group, 41 in the FSW group, and 45 in the TW group completed the study. The 2-year failure rates were 35.7% in the FRC group, 26.8% in the FSW group, and 17.8% in the TW group. These rates differed insignificantly (chi-squared p = 0.167). According to the Kaplan-Meier analysis, failure occurred at 19.95 months in the FRC group, 21.37 months in the FSW group, and 22.36 months in the TW group. The differences between the survival rates in the three groups were not significant (Cox regression p = 0.146). Conclusions Although the failure rate of the experimental retainer was two times lower than that of the FRC retainer, the difference was not statistically significant. The experimental TW retainer was successful, and larger studies are warranted to verify these results. PMID:27019825

  6. Evaluation of the cytotoxicity of fiber reinforced composite bonded retainers and flexible spiral wires retainers in simulated high and low cariogenic environments

    PubMed Central

    Jahanbin, Arezoo; Shahabi, Mostafa; Ahrari, Farzaneh; Bozorgnia, Yasaman; Shajiei, Arezoo; Shafaee, Hooman; Afshari, Jalil Tavakkol

    2015-01-01

    Objectives: The aim of this study was to evaluate the cytotoxic effects of fiber reinforced composite bonded retainers in comparison with flexible spiral wires (FSWs) under high and low cariogenic-simulated environments using human oral fibroblasts. Materials and Methods: Four types of bonded retainers were evaluated: (1) reinforced with glass fibers: Interlig (Angelus), (2) reinforced with polyethylene fibers: Connect (Kerr), (3) reinforced with quartz fibers: Quartz Splint UD (RTD), and (4) FSW. Twenty specimens of each sample group were prepared with the same surface area and halved. Next, half of them were placed in a high cariogenic environment 60 min in 10% lactic acid 3 times a day and remained in Fusayama Meyer artificial saliva for the rest of the day) and the other half were placed in a low cariogenic environment 20 min in 10% lactic acid 3 times a day and remained in Fusayama Meyer artificial saliva for the rest of the day) for 1, 7 and 30 days. Cell viability was assessed by MTT assay. Data were analyzed using SPSS software (α =0.05). Results: During the 1st month, cytotoxicity reduced gradually. In the low cariogenic-simulated environment, the cytotoxicity of all of the groups were reported to be mild at day 30 and the difference between them was significant (P = 0.016). In the same period in the high cariogenic-simulated environment, the cytotoxicity of Connect and Quartz Splint was mild, and they had lower cytotoxicity than the other groups. Meanwhile, Interlig had moderate (52%) and FSW had severe cytotoxicity (22%) and the difference between the groups was also significant (P = 0.000). Conclusions: FSW retainers are not recommended in those at high-risk for dental caries. However, in those at low-risk, there is no difference from the standpoint of cytotoxicity. PMID:25657987

  7. [Influence of retainer design on fixation strength of resin-bonded glass fiber reinforced composite fixed cantilever dentures].

    PubMed

    Petrikas, O A; Voroshilin, Iu G; Petrikas, I V

    2013-01-01

    Fiber-reinforced composite (FRC) fixed partial dentures (FPD) have become an accepted part of the restorative dentist's armamentarium. The aim of this study was to evaluate in vitro the influence of retainer design on the strength of two-unit cantilever resin-bonded glass FRC-FPDs. Four retainer designs were tested: a dual wing, a dual wing + horizontal groove, a dual wing + occlusal rest and a step-box. Of each design on 7 human mandibular molars, FRC-FPDs of a premolar size were produced. The FRC framework was made of resin Revolution (Kerr) impregnated glass fibers (GlasSpan, GlasSpan) and veneered with hybrid resin composite (Charisma, Kulzer). Revolution (Kerr) was used as resin luting cement. FRC-FPDs were loaded to failure in a universal testing machine. T (Student's)-test was used to evaluate the data. The four designs were analyzed with finite element analysis (FEA) to reveal the stress distribution within the tooth/restoration complex. Significantly lower fracture strengths were observed with inlay-retained FPDs (step-box: 172±11 N) compared to wing-retained FPDs (p<0.05) (a dual wing + horizontal groove 222±9 N). The highest fracture strengths were observed with dual wing + occlusal rest FPDs: 250±10 N compared to inlay-retained FPDs (p<0.001) and wing-retained FPDs (p<0.001). FEA showed more favorable stress distributions within the tooth/restoration complex for dual wing retainers+ occlusal rest FPDs. There was stress concentration around connectors and retainers near connectors. A dual-wing retainer with occlusal rest is the optimal design for replacement of a single premolar by means of a two-unit cantilever FRC-FPDs. PMID:23715455

  8. Underground barrier construction apparatus with soil-retaining shield

    DOEpatents

    Gardner, B.M.; Smith, A.M.; Hanson, R.W.; Hodges, R.T.

    1998-08-04

    An apparatus is described for building a horizontal underground barrier by cutting through soil and depositing a slurry, preferably one which cures into a hardened material. The apparatus includes a digging means for cutting and removing soil to create a void under the surface of the ground, a shield means for maintaining the void, and injection means for inserting barrier-forming material into the void. In one embodiment, the digging means is a continuous cutting chain. Mounted on the continuous cutting chain are cutter teeth for cutting through soil and discharge paddles for removing the loosened soil. This invention includes a barrier placement machine, a method for building an underground horizontal containment barrier using the barrier placement machine, and the underground containment system. Preferably the underground containment barrier goes underneath and around the site to be contained in a bathtub-type containment. 17 figs.

  9. Underground barrier construction apparatus with soil-retaining shield

    DOEpatents

    Gardner, Bradley M.; Smith, Ann Marie; Hanson, Richard W.; Hodges, Richard T.

    1998-01-01

    An apparatus for building a horizontal underground barrier by cutting through soil and depositing a slurry, preferably one which cures into a hardened material. The apparatus includes a digging means for cutting and removing soil to create a void under the surface of the ground, a shield means for maintaining the void, and injection means for inserting barrier-forming material into the void. In one embodiment, the digging means is a continuous cutting chain. Mounted on the continuous cutting chain are cutter teeth for cutting through soil and discharge paddles for removing the loosened soil. This invention includes a barrier placement machine, a method for building an underground horizontal containment barrier using the barrier placement machine, and the underground containment system. Preferably the underground containment barrier goes underneath and around the site to be contained in a bathtub-type containment.

  10. Fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro

    PubMed Central

    Foek, Dave Lie Sam; Özcan, Mutlu

    2013-01-01

    Objective To analyze the fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro. Methods Roots of human mandibular central incisors were covered with silicone, mimicking the periodontal ligament, and embedded in polymethylmethacrylate. The specimens (N = 50), with two teeth each, were randomly divided into five groups (n = 10/group) according to the retainer materials: (1) Interlig (E-glass), (2) everStick Ortho (E-glass), (3) DentaPreg Splint (S2-glass), (4) Ribbond (polyethylene), and (5) Quad Cat wire (stainless steel). After the recommended adhesive procedures, the retainers were bonded to the teeth by using flowable composite resin (Tetric Flow). The teeth were subjected to 10,00,000 cyclic loads (8 Hz, 3 - 100 N, 45° angle, under 37 ± 3℃ water) at their incisoproximal contact, and debonding forces were measured with a universal testing machine (1 mm/min crosshead speed). Failure sites were examined under a stereomicroscope (×40 magnification). Data were analyzed by one-way analysis of variance. Results All the specimens survived the cyclic loading. Their mean debonding forces were not significantly different (p > 0.05). The DentaPreg Splint group (80%) showed the highest incidence of complete adhesive debonding, followed by the Interlig group (60%). The everStick Ortho group (80%) presented predominantly partial adhesive debonding. The Quad Cat wire group (50%) presented overlying composite detachment. Conclusions Cyclic loading did not cause debonding. The retainers presented similar debonding forces but different failure types. Braided stainless steel wire retainers presented the most repairable failure type. PMID:24015388

  11. Efficacy of Esthetic Retainers: Clinical Comparison between Multistranded Wires and Direct-Bond Glass Fiber-Reinforced Composite Splints

    PubMed Central

    Scribante, Andrea; Sfondrini, Maria Francesca; Broggini, Simona; D'Allocco, Marina; Gandini, Paola

    2011-01-01

    The purpose of this longitudinal prospective randomized study was to evaluate the reliability of two different types of orthodontic retainers in clinical use: a multistrand stainless steel wire and a polyethylene ribbon-reinforced resin composite. Moreover the level of satisfaction of the patient about the esthetic result was also analyzed by means of a Visual Analogue Scale (VAS). 34 patients (9 boys and 25 girls, mean age 14.3), in the finishing phase of orthodontic treatment, were selected for the study. Since splints were applied the number, cause, and date of splint failures were recorded for each single tooth over 12 months. Statistical analysis was performed using a paired t-test, Kaplan Meier survival estimates, and the log-rank test. Kruskal Wallis test was performed to analyze VAS recordings. Differences between the bond failure rates were not statistically significant. Esthetic result of VAS was significantly higher for polyethylene ribbon-reinforced resin retainers than for stainless steel wires. PMID:22114597

  12. Clinical evaluation of bond failures and survival between mandibular canine-to-canine retainers made of flexible spiral wire and fiber-reinforced composite

    PubMed Central

    Sfondrini, Maria F.; Fraticelli, Danilo; Castellazzi, Linda; Gandini, Paola

    2014-01-01

    Objectives: The purpose of this longitudinal prospective randomized study was to evaluate the clinical reliability of two different types of postorthodontic treatment retainers: a silanised-treated glass fibers-reinforced resin composite (FRC) and a directly bonded multistranded stainless steel wire. The hypothesis of the study was to assess if significant differences are present between failure rates of the two retainers. Study Design: This prospective study was based on an assessment of 87 patients (35 men and 52 women),with an average age of 24 years who required a lower arch fixed retainer after orthodontic treatment. Patients were divided in two groups. Assignment was carried out with random tables. A follow-up examination was carried out once a month. The number, cause, and date of single bond adhesive failures were recorded for both retainers over 12 months. Teeth that were rebonded after failure were not included in the success analysis. Statistical analysis was performed by means of a Fisher’s exact test, Kaplan-Meier survival estimates, and log rank test. Results: Bond failure rate was significantly higher (P=0.0392) for multistranded metallic wire than for FRC. Conclusions: Glass fiber-reinforced resin composite retainers and multistranded metallic wires showed no significant difference in single bond failure rates over a one-year follow up. Key words:Fiber reinforced composite, fixed retention, multistranded wire, orthodontics, retainer, splint. PMID:24790714

  13. Potential use of lateritic and marine clay soils as landfill liners to retain heavy metals.

    PubMed

    Chalermyanont, Tanit; Arrykul, Surapon; Charoenthaisong, Nanthanit

    2009-01-01

    The potential of a lateritic soil and a marine clay, typical of those found in hot and humid climatic regions, was assessed for use as a landfill liner material. A series of tests were conducted - physical and chemical, batch adsorption, column, hydraulic conductivity, etc., - to evaluate the heavy metal sorption capacity, chemical compatibility of hydraulic conductivity, and transport parameters of the soils. Experimental results showed that the marine clay had better adsorption capacity than that of the lateritic soil and that its hydraulic conductivity was an order of magnitude lower. In addition, the hydraulic conductivities of both soils when permeated with low concentration heavy metal solutions were below 1x10(-7)cm/s. When permeated with Cr, Pb, Cd, Zn, and Ni solutions, the retardation factors of the lateritic soil and the marine clay ranged from 10 to 98 and 37 to 165, respectively, while the diffusion coefficients ranged from 1.0x10(-5) to 7.5x10(-6) and 3.0 to 9.14x10(-7)cm2/s, respectively. For both soils, Cr and Pb were retained relatively well, while Cd, Zn, and Ni were more mobile. The marine clay had higher retardation factors and lower diffusion coefficients, and its hydraulic conductivity was more compatible with Cr solution, than that of the lateritic soil. In general, the properties of the marine clay indicate that it has significant advantages over the lateritic soil as landfill liner material. PMID:18550353

  14. Plastic Fibre Reinforced Soil Blocks as a Sustainable Building Material

    NASA Astrophysics Data System (ADS)

    Prasad, C. K. Subramania; Nambiar, E. K. Kunhanandan; Abraham, Benny Mathews

    2012-10-01

    Solid waste management, especially the huge quantity of waste plastics, is one of the major environmental concerns nowadays. Their employability in block making in the form of fibres, as one of the methods of waste management, can be investigated through a fundamental research. This paper highlights the salient observations from a systematic investigation on the effect of embedded fibre from plastic waste on the performance of stabilised mud blocks. Stabilisation of the soil was done by adding cement, lime and their combination. Plastic fibre in chopped form from carry bags and mineral water bottles were added (0.1% & 0.2% by weight of soil) as reinforcement. The blocks were tested for density, and compressive strength, and observed failure patterns were analysed. Blocks with 0.1% of plastic fibres showed an increase in strength of about 3 to 10%. From the observations of failure pattern it can be concluded that benefits of fibre reinforcement includes both improved ductility in comparison with raw blocks and inhibition of crack propogation after its initial formation.

  15. Survival of post-treatment canine-to-canine lingual retainers with fiber-reinforced composite resin: a retrospective study

    PubMed Central

    Farronato, Davide; Briguglio, Roberto; Mangano, Francesco; Azzi, Lorenzo; Grossi, Giovanni Battista; Briguglio, Francesco

    2014-01-01

    Summary The aim of the study is to evaluate the long term results of ribbond retainer after orthodontic treatment. One hundred and thirty patients who were orthodontically treated satisfied the inclusion criteria of having received a semipermanent retention were treated with FRC lingual retainers (Ribbond ®). It was performed a follow up evaluation after 2 years average from the retainer application and any complication or failure was recorded. Data from 119 remaining patients that met the inclusion criteria were analyzed and no instances of loosening were observed. It may be concluded that orthodontic canine-to-canine FRC retainers provide aneffective means of retaining realigned anterior teeth for at least two years. PMID:25506411

  16. Biomechanical comparison of implant retained fixed partial dentures with fiber reinforced composite versus conventional metal frameworks: a 3D FEA study.

    PubMed

    Erkmen, Erkan; Meriç, Gökçe; Kurt, Ahmet; Tunç, Yahya; Eser, Atılım

    2011-01-01

    Fiber reinforced composite (FRC) materials have been successfully used in a variety of commercial applications. These materials have also been widely used in dentistry. The use of fiber composite technology in implant prostheses has been previously presented, since they may solve many problems associated with metal alloy frameworks such as corrosion, complexity of fabrication and high cost. The hypothesis of this study was that an FRC framework with lower flexural modulus provides more even stress distribution throughout the implant retained fixed partial dentures (FPDs) than a metal framework does. A 3-dimensional finite element analysis was conducted to evaluate the stress distribution in bone, implant-abutment complex and prosthetic structures. Hence, two distinctly different models of implant retained 3-unit fixed partial dentures, composed of Cr-Co and porcelain (M-FPD model) or FRC and particulate composite (FRC-FPD model) were utilized. In separate load cases, 300 N vertical, 150 N oblique and 60 N horizontal forces were simulated. When the FRC-FPD and M-FPD models were compared, it was found that all investigated stress values in the M-FPD model were higher than the values in the FRC-FPD model except for the stress values in the implant-abutment complex. It can be concluded that the implant supported FRC-FPD could eliminate the excessive stresses in the bone-implant interface and maintain normal physiological loading of the surrounding bone, therefore minimizing the risk of peri-implant bone loss due to stress-shielding. PMID:21094484

  17. Is Regional Root Reinforcement Controlled by Soil Moisture Variability?

    NASA Astrophysics Data System (ADS)

    Hales, T.; Ford, C. R.

    2011-12-01

    Climate change will alter the amount, type (i.e., snow vs. rain), and timing of precipitation that controls many hazardous Earth surface processes, including debris flows. Most GCMs agree that as climate warms the frequency of extreme precipitation will increase across the globe. Debris flow events triggered by heavy precipitation will likely also increase. Precipitation also affects the resistance to debris flow initiation by controlling belowground plant hydraulic architecture (e.g. root frequency, diameter distribution, tensile strength). Quantifying the links between precipitation, below ground properties, and the processes that initiate debris flows are therefore critical to understanding future hazard. To explore these links, we conducted a field experiment in the Coweeta Hydrologic Laboratory by excavating 12 soil pits (~1 m3), from two topographies (noses, hollows), and two tree species (Liriodendron tulipifera and Betula lenta). For each species and topography, we collected all biomass from five soil depths and measured soil moisture at 30, 60, and 90cm depth. For each depth we also measured root tensile strength, root cellulose content. Where we collected soil moisture data, we also measured root and soil hydraulic conductivity. Our data show a link between soil moisture content and root biomass distribution; root biomass is more evenly distributed through the soil column in hollows compared to noses. This relationship is consistent with the hypothesis that more consistent soil moisture in hollows allows plant roots to access resources from deeper within the soil column. This physiologic control has a significant effect on root cohesion, with trees on noses (or lower average soil moisture) providing greater root cohesion close to the surface, but considerably less cohesion at depth. Root tensile strength correlated with local daily soil moisture rather than the long term differences represented by noses and hollows. Daily soil moisture affected the amount

  18. Behaviour of Cohesionless Soil Reinforced with Three Dimensional Inclusions Under Plane Strain Conditions

    NASA Astrophysics Data System (ADS)

    Harikumar, M.; Sankar, N.; Chandrakaran, S.

    2015-09-01

    Since 1969, when the concept of earth reinforcing was brought about by Henry Vidal, a large variety of materials such as steel bars, tire shreds, polypropylene, polyester, glass fibres, coir and jute fibres etc. have been widely added to soil mass randomly or in a regular, oriented manner. The conventional reinforcements in use were two dimensional or planar, in the form of strips with negligible widths or in the form of sheets. In this investigation, a novel concept of multi oriented plastic reinforcement (hexa-pods) is discussed. Direct shear tests were conducted on unreinforced and reinforced dry fine, medium and coarse sands. Detailed parametric studies with respect to the effective grain size of soil (d10), normal stress (σ) and the volume ratio of hexa-pods (Vr) were performed. It was noticed that addition of hexa-pods resulted in increase in the shear strength parameters viz. peak deviatoric stresses and increased angle of internal friction. The hexa-pods also changed the brittle behaviour of unreinforced sand samples to ductile ones. Although the peak shear stress did not show a considerable improvement, the angle of internal friction improved noticeably. Addition of a single layer of reinforcement along the shear plane also reduced the post peak loss of strength and changed the soil behavior from brittle to a ductile one.

  19. Improving irrigation efficiency of sandy soils by subsurface water retaining membranes

    NASA Astrophysics Data System (ADS)

    Guber, Andrey; Smucker, Alvin; Berhanu, Samrawi

    2014-05-01

    Sustainable crop production in sandy soils is challenging due to low soil water holding capacity and high water permeability. The subsurface water retention technology (SWRT) is a relatively new long-term approach that offers precision control of water and nutrients in the root zone. However, multiple design of SWRT membrane configurations and spatial distributions require more modeling for best application in arid regions with relevant irrigation methods. The objective of this study was to define optimal geometric parameters of the SWRT membranes and the most accurate irrigation rates for corn production in sandy soils. HYDRUS-2D model, that describes two-dimensional water flow in unsaturated soil, was calibrated and validated on data in a large sand-filled lysimeter with SWRT membranes installed at different depths with different aspect ratios. The model adequately reproduced soil water content dynamics measured at 12 locations inside the sand profile. Then HYDRUS-2D simulations were repeated with different SWRT installation depths and aspect ratios. The installation depths in these simulations were 20 cm, 40 cm, and 60 cm, while the aspect ratios were 2:1, 3:1, 5:1 and 10:1. The results of simulations confirmed water holding capacity of the soil can be differentially controlled by aspect ratios of SWRT membranes. SWRT membranes with an aspect ratio of 2:1 substantially increased soil water content at 20-cm soil layer above the membrane, and this effect diminished with increasing aspect ratio of the membrane. Installation depth within the soil profile had no significant effect on water loss. The HYDRUS-2D simulations were repeated with SWRT installed at depth of 20 cm for sprinkle, surface drip and subsurface drip irrigation. Corn irrigation was triggered at pressure head of -30cm at a depth of 15 cm for all irrigation techniques. Simulated water losses by deep infiltration in sands without SWRT membranes approached 60% with approximately 15% losses when SWRT

  20. Mulch your tomatoes to fight weeds, retain soil moisture and save money

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An on-farm experiment was conducted to determine whether different types of mulches were a cost-effective means of weed management in organic tomato production. Three mulch treatment, bare soil, straw and grass, were applied to drip-irrigated tomatoes at a depth of 7.5 cm. Weed biomass was reduced s...

  1. Manure placement depth impacts on crop yields and N retained in soil.

    PubMed

    Reiman, M; Clay, D E; Carlson, C G; Clay, S A; Reicks, G; Clay, D W; Humburg, D E

    2009-01-01

    The objective of this study was to determine the impact of manure placement depth on crop yield and N retention in soil. Experimental treatments were deep manure injection (45 cm), shallow manure injection (15 cm), and conventional fertilizer-based management with at least three replications per site. Water infiltration, and changes in soil N and P amounts were measured for up to 30 months and crop yield monitored for three seasons following initial treatment. Deep and shallow manure injections differed in soil inorganic N distributions. For example, in the manure slot the spring following application, NO(3)-N in the surface 60 cm was higher (p < .01) when injected 15 cm (21.4 micro g/g) into the soil than 45 cm (11.7 micro g/g), whereas NH(4)-N had opposite results with shallow injection having less (p = 0.045) NH(4)-N (102 micro g/g) than deep (133 micro g/g) injection. In the fall one year after the manure was applied, NO(3)-N and NH(4)-N were lower (p = 0.001) in the shallow injection than the deep injection. The net impact of manure placement on total N was that deep injection had 31, 59, and 44 more kg N ha(- 1) than the shallow injection treatment 12, 18, and 30 months after application, respectively. Deep manure injection did not impact soybean (Glycine max L.) yield, however corn (Zea mays L.) yield increased if N was limiting. The higher corn yield in the deep injected treatment was attributed to increased N use efficiency. Higher inorganic N amounts in the deep injection treatment were attributed to reduced N losses through ammonia volatilization, leaching, or denitrification. Results suggest that deep manure placement in glacial till soil may be considered a technique to increase energy, N use efficiency, and maintain surface and ground water quality. However, this technique may not work in glacial outwash soils due to the inability to inject into a rocky subsurface. PMID:19089718

  2. Deformation Behaviors of Geosynthetic Reinforced Soil Walls on Shallow Weak Ground

    NASA Astrophysics Data System (ADS)

    Kim, You-Seong; Won, Myoung-Soo

    In this study, the fifteen-month behavior of two geosynthetic reinforced soil walls, which was constructed on the shallow weak ground, was measured and analyzed. The walls were backfilled with clayey soil obtained from the construction site nearby, and the safety factors obtained from general limit equilibrium analysis were less than 1.3 in both wall. To compare with the measured data from the real GRS walls and unreinforced soil mass, a series of finite element method (FEM) analyses on two field GRS walls and unreinforced soil mass were conducted. The FEM analysis results showed that failure plane of unreinforced soil mass was consistent with the Rankine active state, but failure plane did not occur in GRS walls. In addition, maximum horizontal displacements and shear strains in GRS walls were 50% smaller than those found in unreinforced soil mass. Modeling results such as the maximum horizontal displacements, horizontal pressure, and geosynthetic tensile strengths in GRS wall have a god agreement with the measured data. Based on this study, it could be concluded that geosynthetic reinforcement are effective to reduce the displacement of the wall face and/or the deformation of the backfill soil even if the mobilized tensile stress after construction is very small.

  3. Quantifying root-reinforcement of river bank soils by four Australian tree species

    NASA Astrophysics Data System (ADS)

    Docker, B. B.; Hubble, T. C. T.

    2008-08-01

    The increased shear resistance of soil due to root-reinforcement by four common Australian riparian trees, Casuarina glauca, Eucalyptus amplifolia, Eucalyptus elata and Acacia floribunda, was determined in-situ with a field shear-box. Root pull-out strengths and root tensile-strengths were also measured and used to evaluate the utility of the root-reinforcement estimation models that assume simultaneous failure of all roots at the shear plane. Field shear-box results indicate that tree roots fail progressively rather than simultaneously. Shear-strengths calculated for root-reinforced soil assuming simultaneous root failure, yielded values between 50% and 215% higher than directly measured shear-strengths. The magnitude of the overestimate varies among species and probably results from differences in both the geometry of the root-system and tensile strengths of the root material. Soil blocks under A. floribunda which presents many, well-spread, highly-branched fine roots with relatively higher tensile strength, conformed most closely with root model estimates; whereas E. amplifolia, which presents a few, large, unbranched vertical roots, concentrated directly beneath the tree stem and of relatively low tensile strength, deviated furthest from model-estimated shear-strengths. These results suggest that considerable caution be exercised when applying estimates of increased shear-strength due to root-reinforcement in riverbank stability modelling. Nevertheless, increased soil shear strength provided by tree roots can be calculated by knowledge of the Root Area Ratio ( RAR) at the shear plane. At equivalent RAR values, A. floribunda demonstrated the greatest earth reinforcement potential of the four species studied.

  4. The self-reinforcing feedback between low soil fertility and chronic poverty

    NASA Astrophysics Data System (ADS)

    Barrett, Christopher B.; Bevis, Leah E. M.

    2015-12-01

    Most of the world's extreme poor, surviving on US$1.25 or less per day, live in rural areas and farm for a living. Many suffer chronic poverty that lasts for years or generations, rather than the transitory poverty that dominates developed, urban economies. Such chronic, structural poverty arises when an individual's productive assets -- such as their ability to work or their soils -- and the technologies and markets that transform their assets into food and income are insufficient to attain satisfactory living standards. Research reveals strong links between economic status and soil quality, and these can be self-reinforcing. For example, poor soil constrains agricultural production and household capital, and low household capital constrains investments in improving soils. Price, availability and access to credit can limit farmers' applications of nutrients, which are often the primary constraint on agricultural productivity. Soil micronutrient deficiencies can lead to dietary mineral deficiencies and negative health outcomes that further constrain productivity and household asset accumulation. Soils may also be important for smallholder resilience to stressors and shocks. For example, high-quality soil can reduce vulnerability to drought, and insurance against risk may promote investment in soils. Interventions such as fertilizer subsidies, micronutrient-fortified fertilizer and improved access to information, insurance and credit may all help break the soil-poverty cycle.

  5. Covering of fiber-reinforced composite bars by adhesive materials, is it necessary to improve the bond strength of lingual retainers?

    PubMed Central

    Heravi, Farzin; Kerayechian, Navid; Moazzami, Saied Mostafa; Shafaee, Hooman; Heravi, Parya

    2015-01-01

    Objectives: The objectives were to evaluate the shear bond strength (SBS) of fiber-reinforced composite (FRC) retainers when bonding them to teeth with and without covering the FRC bars using two different adhesive systems. Materials and Methods: Hundred and twenty extracted human maxillary premolars were randomly divided into eight groups (n = 15). FRC bars (4 mm length, Everstick Ortho®, Stick Tech, Oy, Turku, Finland) were bonded to the proximal (distal) surfaces of the teeth using two different adhesives (Tetric Flow [TF, Ivoclar Vivadent, Switzerland] and resin-modified glass ionomer cement [RMGIC, ODP, Vista, CA, USA]) with and without covering with the same adhesive. Specimens were exposed to thermocycling (625 cycles per day [5–55°C, intervals: 30 s] for 8 days). The SBS test was then performed using the universal testing machine (Zwick, GMBH, Ulm, Germany). After debonding, the remaining adhesive on the teeth was recorded by the adhesive remnant index (0–3). Results: The lowest mean SBS (standard deviation) was found in the TF group without covering with adhesive (12.6 [2.11] MPa), and the highest bond strength was in the TF group with covering with adhesive (16.01 [1.09] MPa). Overall, the uncovered RMGIC (15.65 [3.57] MPa) provided a higher SBS compared to the uncovered TF. Covering of FRC with TF led to a significant increase in SBS (P = 0.001), but this was not true for RMGIC (P = 0.807). Thermal cycling did not significantly change the SBS values (P = 0.537). Overall, eight groups were statistically different (ANOVA test, F = 3.32, P = 0.034), but no significant differences in bond failure locations were found between the groups (Fisher's exact tests, P = 0.92). Conclusions: The present findings showed no significant differences between SBS of FRC bars with and without covering by RMGIC. However, when using TF, there was a significant difference in SBS measurements between covering and noncovering groups. Therefore, the use of RMGIC without

  6. Performance of improved ground and reinforced soil structures during earthquakes: Case studies and numerical analyses

    NASA Astrophysics Data System (ADS)

    Olgun, C. Guney

    The 1999 Kocaeli Earthquake (M=7.4) struck northwestern Turkey on August 17, 1999 and caused significant damage in urban areas located along Izmit Bay. The sites that suffered the greatest damages were located primarily in areas of poorest soil conditions, typically containing soft clays and silts and/or loose, liquefiable sands. Because the affected region is heavily developed with infrastructure and there is a preponderance of poor soils, a wide range of soil improvement measures had been used to mitigate anticipated earthquake damages throughout the region. Following the earthquake and significant aftershocks, Virginia Tech researchers traveled to Turkey to investigate the affected area to document geotechnical field performance. Primary focus of the Virginia tech team was given to investigating the performance of improved soil sites and reinforced soil structures. The sites were subjected to ground motions ranging from about 0.10g to 0.35g. The site locations ranged from 0 to 35 km from the zone of energy release. This dissertation presents in detail, the findings from the two most instructive sites. The investigation of these sites involved field reconnaissance, field and laboratory testing of soils, seismic analysis, numerical modeling, and other analytical work.

  7. Load-bearing capacity of indirect inlay-retained fixed dental prostheses made of particulate filler composite alone or reinforced with E-glass fibers impregnated with various monomers.

    PubMed

    Özcan, Mutlu; Koekoek, Winand; Pekkan, Gurel

    2012-08-01

    The load-bearing capacity and failure types of indirect inlay-retained fixed dental prostheses (FDP), made of particulate filler composite (PFC) (Estenia) alone or reinforced with E-glass fibers impregnated with various monomers were evaluated. Indirect inlay-retained FDPs were made between first premolars and first molars (N=30, 10/per group). The inlay parts of the specimens were silica coated and silanized and the specimens were cemented with dual-polymerized resin cement under ultrasonic vibrations. The experimental groups were as follows: Group 1: FRC1 (BR-100, UTMA) + PFC; Group 2: FRC2 (everStick C&B, Bis-GMA/PMMA) + PFC; Group 3: PFC only. The specimens were kept in distilled water at 37 °C for one month and then subjected to fracture strength test. No significant difference was found between the Group 1 and Group 2 FDPs (1357±301 N and 1213±316 N, respectively) (p>0.05) (ANOVA). Group 3 (856±299 N) showed significantly lower results than those of FRC reinforced groups (p<0.05). Failure analyses revealed no debonding of any of the FDPs from the inlay cavities. FDPs made of PFC only showed mainly catastrophic fracture of the pontic. In the FRC reinforced groups, predominantly delamination of the veneering was observed. The use of silica coating and silanization in combination with the dual-polymerized resin cement used; under ultrasonic cementation procedure provided sufficient adhesion to withstand static loading forces at the cementation interface, since the failures were predominantly delamination of the veneering in the FRC reinforced groups. PMID:22732482

  8. Bicruciate retaining

    PubMed Central

    2016-01-01

    Total knee replacement (TKR) is a procedure used to treat knee arthropathy. Patients’ dissatisfaction is still relevant (literature reports dissatisfaction rates as high as 40%). The anterior cruciate ligament is usually removed while performing a total knee arthroplasty, thus changing knee biomechanics. As patients’ mean age to surgery is decreasing, bicruciate retaining models, which preserve normal biomechanics, may be useful in increasing patients’ outcomes. Limited data concerning bicruciate retaining arthroplasty is available; although clinical results are encouraging, there are concerns regarding surgical exposure, anterior cruciate integrity evaluation, and implant fixation. PMID:27162778

  9. Composting of biochars improves their sorption properties, retains nutrients during composting and affects greenhouse gas emissions after soil application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar application to soils has been suggested to elevate nutrient sorption, improve soil fertility and reduce net greenhouse gas (GHG) emissions. We examined the impact of composting biochar together with a biologically active substrate (i.e., livestock manure-straw mixture). We hypothesized that ...

  10. Inlay-fixed partial dentures adhesively retained and reinforced by glass fibers: clinical and scanning electron microscopy analysis after five years.

    PubMed

    Göhring, Till N; Roos, Malgorzata

    2005-02-01

    Fifty-three posterior glass fibre-reinforced composite inlay-fixed partial dentures (IFPDs) in 36 patients were followed for 5 yr. For statistical analysis, one IFPD per patient was randomly selected. The survival rate and influence of discrete predictors (gender, location) and continuous variables (age, abutment surfaces) were determined. Clinical observations were recorded by using modified United States Public Health System (USPHS) criteria. Replicas of 17 randomly selected abutments were analysed by scanning electron microscopy (SEM) for marginal adaptation and the results were compared by using a repeated-measures analysis of variance (anova). The main reason for failure was veneering material delamination from the framework. The cumulative survival rate after 5 yr was 73% (95% confidence interval: 57-89%) for not delaminating and 96% (95% confidence interval: 88-100%) for not debonding. No significant influence of the tested predictors was found. Significant changes between baseline USPHS criteria and counterparts recorded at recall were fractures of the veneering material (chipping), wear, surface texture, and staining. Significant margin changes were only found between baseline and 1 yr. Thereafter, marginal adaptation remained stable. After 5 yr, 90% of the margins were termed as perfect. It was concluded that hard-tissue saving IFPDs with the current design maintained acceptable retention and marginal integrity. Future studies should aim at reducing delaminations by searching for improved framework designs and materials. PMID:15693831

  11. The role of non-linear deformation analyses in the design of a reinforced soil berm at Red River U-frame lock No. 1

    NASA Astrophysics Data System (ADS)

    Ebeling, Robert M.; Peters, John F.; Mosher, Reed L.

    1997-11-01

    This paper describes a design application of non-linear deformation analysis to a complex soil-structure-foundation interaction problem through use of a finite element analysis. The problem consists of a proposed renovation to an existing soil-founded U-frame lock structure consisting of construction of a densely reinforced soil berm adjacent to an existing lock wall. Major questions facing the designer involve reduction of the earth pressure on the lock wall, layout of the reinforcing in the soil berm, and collateral effects of berm construction on the U-frame lock structure. A non-linear deformation analysis played a central role in addressing all of these questions. Berm construction and four operational load cases were used to understand the performance of the reinforced berm and to discern interactions among the lock, the backfill, the foundation strata of the U-frame lock, the reinforced berm, and the foundation strata of the reinforced berm. Insight gained from the soil-structure-foundation interaction analyses led to an alteration to the proposed reinforcement layout to enhance the performance of the reinforced soil berm.

  12. Retainer for laboratory animals

    NASA Technical Reports Server (NTRS)

    Lee, R. W.

    1979-01-01

    Bio-retainer holds laboratory animals in fixed position for research and clinical experiments. Retainer allows full access to animals and can be rapidly opened and closed to admit and release specimens.

  13. The retained surgical sponge.

    PubMed Central

    Kaiser, C W; Friedman, S; Spurling, K P; Slowick, T; Kaiser, H A

    1996-01-01

    OBJECTIVE. A review was performed to investigate the frequency of occurrence and outcome of patients who have retained surgical sponges. METHODS. Closed case records from the files of the Medical Professional Mutual Insurance Company (ProMutual, Boston, MA) involving a claim of retained surgical sponges were reviewed for a 7-year period. RESULTS. Retained sponges occurred in 40 patients, comprising 48% of all closed claims for retained foreign bodies. A falsely correct sponge count after an abdominal procedure was documented in 76% of these claims. Ten percent of claims involved vaginal deliveries and minor non-body cavity procedures, for which no sponge count was performed. Total indemnity payments were $2,072,319, and defense costs were $572,079. In three cases, the surgeon was deemed responsible by the court despite the nursing staff's admitting liability and evidence presented that the surgeon complied completely with the standard of care. A wide range of indemnity payments was made despite a remarkable similarity of outcome in the patients studied. CONCLUSIONS. Despite the rarity of the reporting of a retained surgical sponge, this occurrence appears to be encountered more commonly than generally is appreciated. Operating teams should ensure that sponges be counted for all vaginal and any incisional procedures at risk for retaining a sponge. In addition, the surgeon should not unquestioningly accept correct count reports, but should develop the habit of performing a brief but thorough routine postprocedure wound/body cavity exploration before wound closure. The strikingly similar outcome for most patients would argue for a standardized indemnity payment being made without the need for adversarial legal procedures. PMID:8678622

  14. VIEW SHOWING THE ENTRY THROUGH THE RETAINING WALL (FOREGROUND) TO ...

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

    VIEW SHOWING THE ENTRY THROUGH THE RETAINING WALL (FOREGROUND) TO THE CONCRETE SLAB. NOTE THE 1¾" MOUNTING BOLTS FOR THE STEEL PLATE BASE OF THE 5" GUN, SET IN THE GUN BLOCK. STEEL REINFORCING RODS PROTRUDING FROM THE BROKEN TOPS OF THE RETAINING WALLS ARE ALSO VISIBLE. VIEW FACING EAST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, South Gun Emplacement, Ford Island, Pearl City, Honolulu County, HI

  15. Retained gas inventory comparison

    SciTech Connect

    BARTON, W.B.

    1999-05-18

    Gas volume data derived from four different analytical methods were collected and analyzed for comparison to volumes originally used in the technical basis for the Basis for Interim Operations (BIO). The original volumes came from Hodgson (1996) listed in the reference section of this document. Hodgson (1996) screened all 177 single and double-shell tanks for the presence of trapped gas in waste via two analytical methods: Surface Level Rise (SLR), and Barometric Pressure Effect (BPE). More recent gas volume projections have been calculated using different analytical techniques along with updates to the parameters used as input to the SLR and BPE models. Gas volumes derived from new analytical instruments include those as measured by the Void Fraction Instrument (VFI) and Retained Gas Sampler (RGS). The results of this comparison demonstrate that the original retained gas volumes of Hodgson (1996) used as a technical basis in developing the BIO were conservative, and were conservative from a safety analysis standpoint. These results represent only comparisons to the original reported volumes using the limited set of newly acquired data that is available.

  16. Bicruciate retaining arthroplasty.

    PubMed

    Mont, Michael A; John, Mario; Johnson, Aaron

    2012-12-01

    Total knee arthroplasty (TKA) is one of the most successful orthopaedic procedures with 10 to 20 year survivorships from multiple studies of greater than 95%. These success rates typically apply to patients over 70 years of age who may only want to return to activities of daily living. However, recently there is a demand by both senior citizens as well as young patients to have TKAs that return them to high activity levels and occasionally high performance sports. In this review, we will describe bicruciate retaining prostheses, including knowledge of their kinematics from fluoroscopic and gait studies, results of clinical studies, a summary of their potential advantages and disadvantages, anterior cruciate ligament viability at time of arthroplasty, considerations for implantation of these devices, and their role in the future of total knee arthroplasty. PMID:22915498

  17. Polyurethane retainers for ball bearings

    NASA Technical Reports Server (NTRS)

    Christy, R. I.

    1973-01-01

    Evaluation of a new ball bearing retainer material is reported. A special composite polyurethane foam ball retainer has been developed that has virtually zero wear, is chemically inert to hydrocarbon lubricants, and stores up to 60 times as much lubricant per unit volume as the most commonly used retainer material, cotton phenolic. This new retainer concept shows promise of years of ball bearing operation without reoiling, based on life testing in high vacuum.

  18. Retained Placenta Accreta Mimicking Choriocarcinoma

    PubMed Central

    Kohi, Maureen P.; Rizzuto, Gabrielle A.; Fidelman, Nicholas; Lucero, Jennifer; Thiet, Mari-Paule

    2015-01-01

    This case demonstrates a rare event of retained invasive placenta masquerading as choriocarcinoma. The patient presented with heavy vaginal bleeding following vaginal delivery complicated by retained products of conception. Ultrasound and computed tomography demonstrated a vascular endometrial mass, invading the uterine wall and raising suspicion for choriocarcinoma. Hysterectomy revealed retained invasive placenta. PMID:26495146

  19. Spin bearing retainer design optimization

    NASA Technical Reports Server (NTRS)

    Boesiger, Edward A.; Warner, Mark H.

    1991-01-01

    The dynamics behavior of spin bearings for momentum wheels (control-moment gyroscope, reaction wheel assembly) is critical to satellite stability and life. Repeated bearing retainer instabilities hasten lubricant deterioration and can lead to premature bearing failure and/or unacceptable vibration. These instabilities are typically distinguished by increases in torque, temperature, audible noise, and vibration induced by increases into the bearing cartridge. Ball retainer design can be optimized to minimize these occurrences. A retainer was designed using a previously successful smaller retainer as an example. Analytical methods were then employed to predict its behavior and optimize its configuration.

  20. Computation of the seismic stability of earth retaining structures

    SciTech Connect

    1998-07-30

    The purpose of this CRADA project was to evaluate the seismic stability of block retaining wall systems. Retaining wall systems are used extensively in private and commercial developments. This study was designed to develop and demonstrate a computer modeling technology to be used to predict the seismic stability of any block wall system design. The nonlinear finite element computer programs developed at LLNL and employed in the Computational Earthquake Initiative were utilized in this small business CRADA to analyze the seismic stability of the block retaining walls. The unique capability of the LLNL programs to rigorously model frictional contact in a dynamic analysis problem were used in a computer simulation of the dynamic interaction the block wall/soil systems under seismic excitation. Another important application, and the focus of the proposal, was the use of block retaining walls in highway transportation systems to provide a vertical wall to hold back a mass of soil near highway bridges, and at on-ramps and off-ramps. Block retaining walls offered the potential of highway retaining wall construction which was both more flexible and more economical than existing poured-in-place and tilt-up highway retaining wall construction. However, block retaining wall technology was not embraced and utilized in the State of California as a result of seismic stability concerns expressed by Caltrans. Caltrans had an interest in utilizing block wall systems as soil retaining systems for major highway structures in California, but they stated to the block wall manufacturers and the manufacturer's engineering consultants that block retaining walls could not be employed until Caltrans was convinced of the earthquake stability of such systems.

  1. [The 'van der Linden' retainer].

    PubMed

    van der Linden, F P

    2003-11-01

    Normally, only the anterior teeth have to be retained after an orthodontic treatment. For that purpose, a lingually bonded wire is preferred in the mandible and a removable plate in the maxilla. The design of the Van der Linden-retainer is based on theoretical considerations and secures rigid fixation of the six anterior teeth with solid anchorage in that region. A retention plate should not be used to move anterior teeth. However, with instant corrections small improvements can be realized. The fabrication and clinical use of the Van der Linden-retainer is explained and illustrated. PMID:14669487

  2. Quick locking/unlocking retainer

    NASA Technical Reports Server (NTRS)

    Okamoto, G.; Williams, B. B.

    1979-01-01

    Spring clip retainer may prove more convenient than clamps or wingnut and stud combination when holding two small parts together in test fixtures and other applications where parts must be frequently moved or changed.

  3. Retained folates in the rat.

    PubMed Central

    Barford, P A; Staff, R J; Blair, J A

    1977-01-01

    The retention of radioactivity after doses of 14C- and 3H-labelled folic acid is described. Radioactivity was retained in liver, kidney and gut of rats for some time after administration of the dose. The retained radioactivity could not be displaced by large doses of unlabelled folic acid or unlabelled 5-methyltetrahydrofolate. 14C- and 3H-labbelled folates showed similar chromatographic behaviour onion-exchange chromatography to 5-methyltetrahydrofolate, and on ion-exchange and gel-permeation chromatography to synthetic pteroylhepta-gamma-glutamate. PMID:883955

  4. Electrical transmission line diametrical retainer

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy; Pixton, David; Dahlgren, Scott; Sneddon, Cameron; Briscoe, Michael; Fox, Joe

    2004-12-14

    The invention is a mechanism for retaining an electrical transmission line. In one embodiment of the invention it is a system for retaining an electrical transmission line within down hole components. In accordance with one aspect of the invention, the system includes a plurality of downhole components, such as sections of pipe in a drill string. The system also includes a coaxial cable running between the first and second end of a drill pipe, the coaxial cable having a conductive tube and a conductive core within it. The invention allows the electrical transmission line to with stand the tension and compression of drill pipe during routine drilling cycles.

  5. Seismic behavior of geogrid reinforced slag wall

    SciTech Connect

    Edincliler, Ayse; Baykal, Gokhan; Saygili, Altug

    2008-07-08

    Flexible retaining structures are known with their high performance under earthquake loads. In geogrid reinforced walls the performance of the fill material and the interface of the fill and geogrid controls the performance. Geosynthetic reinforced walls in seismic regions must be safe against not only static forces but also seismic forces. The objective of this study is to determine the behavior of a geogrid reinforced slag wall during earthquake by using shaking table experiments. This study is composed of three stages. In the first stage the physical properties of the material to be used were determined. In the second part, a case history involving the use of slag from steel industry in the construction of geogrid reinforced wall is presented. In the third stage, the results of shaking table tests conducted using model geogrid wall with slag are given. From the results, it is seen that slag can be used as fill material for geogrid reinforced walls subjected to earthquake loads.

  6. Screw-Retaining Allen Wrench

    NASA Technical Reports Server (NTRS)

    Granett, D.

    1985-01-01

    Steadying screws with fingers unnecessary. Crimp in uncompressed spring wire slightly protrudes from one facet of Allen wrench. Compressed spring retains Allen screw. Tool used with Allen-head screws in cramped spaces with little or no room for fingers to hold fastener while turned by wrench.

  7. Recruiting and Retaining Summer Staff.

    ERIC Educational Resources Information Center

    Crossen, Brian; Yerkes, Rita

    1998-01-01

    Recruiting of camp staff is challenged by economic and workplace restructuring, including business downsizing, part-time and temporary employment patterns, and generational attitude changes. Strategies for hiring and retaining staff include knowing what college-age workers want, marketing benefits, adopting new business strategies, and empowering…

  8. Recruiting and Retaining Adult Students.

    ERIC Educational Resources Information Center

    Hadfield, Janice

    2003-01-01

    Adult learners, long the stepchildren of colleges and universities, have nearly become the norm, and they spend billions of dollars each year on education. This chapter takes a customer-oriented approach to recruiting and retaining adult students in higher education. (GCP)

  9. Recycling of Reinforced Plastics

    NASA Astrophysics Data System (ADS)

    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.

  10. Retained gas sampler interface volume

    SciTech Connect

    Cannon, N.S.

    1997-10-01

    The maximum Retained Gas Sampler (RGS) interface volume was determined; this volume can trap contamination gases during the sampling process. A new technique (helium backfill) for eliminating contamination gases from the RGS sampler interface volume is described, and verification testing reported. Also demonstrated was that RGS data obtained prior to the introduction of the new helium backfill technique can be compensated for air contamination using the measured oxygen concentration and normal air composition.

  11. Sapphire reinforced alumina matrix composites

    NASA Technical Reports Server (NTRS)

    Jaskowiak, Martha H.; Setlock, John A.

    1994-01-01

    Unidirectionally reinforced A1203 matrix composites have been fabricated by hot pressing. Approximately 30 volume % of either coated or uncoated sapphire fiber was used as reinforcement. Unstabilized ZrO2 was applied as the fiber coating. Composite mechanical behavior was analyzed both after fabrication and after additional heat treatment. The results of composite tensile tests were correlated with fiber-matrix interfacial shear strengths determined from fiber push-out tests. Substantially higher strength and greater fiber pull-out were observed for the coated fiber composites for all processing conditions studied. The coated fiber composites retained up to 95% and 87% of their as-fabricated strength when heat treated at 14000C for 8 or 24 hours, respectively. Electron microscopy analysis of the fracture surfaces revealed extensive fiber pull-out both before and after heat treatment.

  12. Reinforced Carbon Nanotubes.

    DOEpatents

    Ren, Zhifen; Wen, Jian Guo; Lao, Jing Y.; Li, Wenzhi

    2005-06-28

    The present invention relates generally to reinforced carbon nanotubes, and more particularly to reinforced carbon nanotubes having a plurality of microparticulate carbide or oxide materials formed substantially on the surface of such reinforced carbon nanotubes composite materials. In particular, the present invention provides reinforced carbon nanotubes (CNTs) having a plurality of boron carbide nanolumps formed substantially on a surface of the reinforced CNTs that provide a reinforcing effect on CNTs, enabling their use as effective reinforcing fillers for matrix materials to give high-strength composites. The present invention also provides methods for producing such carbide reinforced CNTs.

  13. Transverse Reinforcement in Reinforced Concrete Columns

    NASA Astrophysics Data System (ADS)

    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.

  14. 12 CFR 1805.504 - Retained earnings.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Retained earnings. 1805.504 Section 1805.504.... Retained earnings accumulated after the end of the Applicant's most recent fiscal year ending prior to the... over the Applicant's most recent fiscal year (e.g., retained earnings at the end of fiscal year...

  15. 30 CFR 57.20010 - Retaining dams.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Retaining dams. 57.20010 Section 57.20010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE....20010 Retaining dams. If failure of a water or silt retaining dam will create a hazard, it shall be...

  16. 30 CFR 56.20010 - Retaining dams.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Retaining dams. 56.20010 Section 56.20010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Retaining dams. If failure of a water or silt retaining dam will create a hazard, it shall be of...

  17. The Non-finished, Non-well Compacted Soil of the Crest of Zayzoun Dam, the Technical and Administrative Errors, and the Correct Ways of its Reinforcement and Renovation

    NASA Astrophysics Data System (ADS)

    Hamze, Youssef; Stanivska, Anna

    Zayzoun dam is one of the irrigation elements of the valley of (Alkhab) in northern Syria; its exploitation started in 1996 and breached on June 4th, 2002. There were many experts searching for the causes of its failure and the correct ways of its renovation. There were many reports written about the failure with different opinions, and we have been one of these experts with an objective opinion. The principal aim was to study all the technical and administrative components of the dam, and to analyze the existing and the new laboratory testing. The soil of the unfinished summit of the dam, in the end, was found to be the real cause that led to its failure. These causes will be analyzed in order to avoid them in the future and to find the suitable ways of its renovation and reinforcement.

  18. Triazine Soil Interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fate of triazine herbicides in soils is controlled by three basic processes: transformation, retention, and transport. Sorption of triazines on surfaces of soil particles is the primary means by which triazines are retained in soils. Soils are very complex mixtures of living organisms, various t...

  19. Early Loaded Single Implant Reinforced Mandibular Overdenture.

    PubMed

    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

  20. Early Loaded Single Implant Reinforced Mandibular Overdenture

    PubMed Central

    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

  1. Federal Aviation Administration retained savings program proposal

    SciTech Connect

    Hostick, D.J.; Larson, L.L.; Hostick, C.J.

    1998-03-01

    Federal legislation allows federal agencies to retain up to 50% of the savings associated with implementing energy efficiency and water conservation measures and practices. Given budget pressures to reduce expenditures, the use of retained savings to fund additional projects represents a source of funds outside of the traditional budget cycle. The Southwest Region Federal Aviation Administration (FAA) has tasked Pacific Northwest National Laboratory (PNNL) to develop a model retained savings program for Southwest Region FAA use and as a prototype for consideration by the FAA. PNNL recommends the following steps be taken in developing a Southwest Region FAA retained savings program: Establish a retained savings mechanism. Determine the level at which the retained savings should be consolidated into a fund. The preliminary recommendation is to establish a revolving efficiency loan fund at the regional level. Such a mechanism allows some consolidation of savings to fund larger projects, while maintaining a sense of facility ownership in that the funds will remain within the region.

  2. A new type of clear orthodontic retainer incorporating multi-layer hybrid materials

    PubMed Central

    Ahn, Hyo-Won; Kim, Kyung A

    2015-01-01

    Clear thermoplastic retainers have been widely used in daily orthodontics; however, they have inherent limitations associated with thermoplastic polymer materials such as dimensional instability, low strength, and poor wear resistance. To solve these problems, we developed a new type of clear orthodontic retainer that incorporates multi-layer hybrid materials. It consists of three layers; an outer polyethylenterephthalate glycol modified (PETG) hard-type polymer, a middle thermoplastic polyurethane (TPU) soft-type polymer, and an inner reinforced resin core. The resin core improves wear resistance and mechanical strength, which prevent unwanted distortion of the bucco-palatal wall of the retainer. The TPU layer absorbs impact and the PETG layer has good formability, optical qualities, fatigue resistance, and dimensional stability, which contributes to increased support from the mandibular dentition, and helps maintain the archform. This new type of vacuum-formed retainer showed improved mechanical strength and rate of water absorption. PMID:26445722

  3. Modeling of geosynthetic reinforced capping systems

    SciTech Connect

    Viswanadham, B.V.S.; Koenig, D.; Jessberger, H.L.

    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.

  4. Conservative Approach for Restoring Posterior Missing Tooth with Fiber Reinforcement Materials: Four Clinical Reports

    PubMed Central

    Karaarslan, Emine Sirin; Ertas, Ertan; Ozsevik, Semih; Usumez, Aslihan

    2011-01-01

    Adhesively luted, fiber-reinforced, composite-inlay, retained fixed-partial dentures can be a clinical alternative for the replacement of missing posterior teeth in selective situations. This type of restoration allows for satisfactory esthetics and reduced tooth preparation compared to a conventional, fixed-partial denture. This clinical report describes the use of a fiber-reinforced, composite-inlay, retained fixed-partial denture as a conservative alternative for the replacement of missing posterior teeth. PMID:21912503

  5. 12 CFR 1805.504 - Retained earnings.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... Retained earnings accumulated after the end of the Applicant's most recent fiscal year ending prior to the... over the Applicant's most recent fiscal year (e.g., retained earnings at the end of fiscal year 2003... that has occurred over the Applicant's three most recent fiscal years. (c)(1) In the case of...

  6. Inadvertent tooth movement with fixed lingual retainers.

    PubMed

    Shaughnessy, Timothy G; Proffit, William R; Samara, Said A

    2016-02-01

    Fixed retainers are effective in maintaining the alignment of the anterior teeth more than 90% of the time, but they can produce inadvertent tooth movement that in the most severe instances requires orthodontic retreatment managed with a periodontist. This is different from relapse into crowding when a fixed retainer is lost. These problems arise when the retainer breaks but remains bonded to some or all teeth, or when an intact retainer is distorted by function or was not passive when bonded. In both instances, torque of the affected teeth is the predominant outcome. A fixed retainer made with dead soft wire is the least likely to create torque problems but is the most likely to break. Highly flexible twist wires bonded to all the teeth appear to be the most likely to produce inadvertent tooth movement, but this also can occur with stiffer wires bonded only to the canines. Orthodontists, general dentists, and patients should be aware of possible problems with fixed retainers, especially those with all teeth bonded, because the patient might not notice partial debonding. Regular observations of patients wearing fixed retainers by orthodontists in the short term and family dentists in the long term are needed. PMID:26827985

  7. Retained garden fork following cranial stab injury

    PubMed Central

    Gonya, Sonwabile; Mbatha, Andile; Moyeni, Nondabula; Enicker, Basil

    2016-01-01

    Retained garden fork is a rare complication of penetrating cranial trauma. Retained knife blade is the most commonly reported presentation. We report an unusual case of a 30-year-old male patient treated at our institution, who presented with a retained garden fork following a stab to the head, with no associated neurological deficits. Computerized tomographic scan of the brain was performed preoperatively to assess the trajectory of the weapon and parenchymal injury. A craniectomy was performed to facilitate removal of the weapon in the operating theatre under general anaesthesia. Intravenous prophylactic antibiotics were administered pre- and postoperatively to prevent septic complications. The patient recovered well and was discharged home. PMID:26747398

  8. Effective reinforcement learning following cerebellar damage requires a balance between exploration and motor noise

    PubMed Central

    Therrien, Amanda S.; Wolpert, Daniel M.

    2016-01-01

    See Miall and Galea (doi: 10.1093/awv343) for a scientific commentary on this article. Reinforcement and error-based processes are essential for motor learning, with the cerebellum thought to be required only for the error-based mechanism. Here we examined learning and retention of a reaching skill under both processes. Control subjects learned similarly from reinforcement and error-based feedback, but showed much better retention under reinforcement. To apply reinforcement to cerebellar patients, we developed a closed-loop reinforcement schedule in which task difficulty was controlled based on recent performance. This schedule produced substantial learning in cerebellar patients and controls. Cerebellar patients varied in their learning under reinforcement but fully retained what was learned. In contrast, they showed complete lack of retention in error-based learning. We developed a mechanistic model of the reinforcement task and found that learning depended on a balance between exploration variability and motor noise. While the cerebellar and control groups had similar exploration variability, the patients had greater motor noise and hence learned less. Our results suggest that cerebellar damage indirectly impairs reinforcement learning by increasing motor noise, but does not interfere with the reinforcement mechanism itself. Therefore, reinforcement can be used to learn and retain novel skills, but optimal reinforcement learning requires a balance between exploration variability and motor noise. PMID:26626368

  9. Effective reinforcement learning following cerebellar damage requires a balance between exploration and motor noise.

    PubMed

    Therrien, Amanda S; Wolpert, Daniel M; Bastian, Amy J

    2016-01-01

    Reinforcement and error-based processes are essential for motor learning, with the cerebellum thought to be required only for the error-based mechanism. Here we examined learning and retention of a reaching skill under both processes. Control subjects learned similarly from reinforcement and error-based feedback, but showed much better retention under reinforcement. To apply reinforcement to cerebellar patients, we developed a closed-loop reinforcement schedule in which task difficulty was controlled based on recent performance. This schedule produced substantial learning in cerebellar patients and controls. Cerebellar patients varied in their learning under reinforcement but fully retained what was learned. In contrast, they showed complete lack of retention in error-based learning. We developed a mechanistic model of the reinforcement task and found that learning depended on a balance between exploration variability and motor noise. While the cerebellar and control groups had similar exploration variability, the patients had greater motor noise and hence learned less. Our results suggest that cerebellar damage indirectly impairs reinforcement learning by increasing motor noise, but does not interfere with the reinforcement mechanism itself. Therefore, reinforcement can be used to learn and retain novel skills, but optimal reinforcement learning requires a balance between exploration variability and motor noise. PMID:26626368

  10. VIEW OF EAST GUN EMPLACEMENT. NOTE THE STEEL REINFORCING RODS ...

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

    VIEW OF EAST GUN EMPLACEMENT. NOTE THE STEEL REINFORCING RODS PROTRUDING FROM THE BROKEN TOP OF THE RETAINING WALL. VIEW FACING NORTHEAST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, East Gun Emplacement, Ford Island, Pearl City, Honolulu County, HI

  11. Strain Gauges Mounted To Retain Calibration

    NASA Technical Reports Server (NTRS)

    Butler, Barry L.

    1993-01-01

    Silicon-based semiconductor strain gauges mounted in such way they retain original calibration for several years instead of few months. Improvement effected by bonding gauges to ceramic substrates with glasses instead of epoxies as adhesives.

  12. Attracting and retaining nurses in HIV care.

    PubMed

    Puplampu, Gideon L; Olson, Karin; Ogilvie, Linda; Mayan, Maria

    2014-01-01

    Attracting and retaining nurses in HIV care is essential to treatment success, preventing the spread of HIV, slowing its progression, and improving the quality of life of people living with HIV. Despite the wealth of studies examining HIV care, few have focused on the factors that influenced nurses' choices to specialize in HIV care. We examined the factors that attracted and retained eight nurses currently working in HIV care in two large Canadian cities. Participants were primarily women between the ages of 20 and 60 years. Interviews were conducted between November 2010 and September 2011 using interpretive description, a qualitative design. Factors that influenced participants to focus their careers in HIV care included both attracting factors and retaining factors. Although more research is needed, this exploration of attracting and retaining factors may motivate others to specialize in HIV nursing, and thus help to promote adequate support for individuals suffering from the disease. PMID:23499392

  13. Habituation of reinforcer effectiveness.

    PubMed

    Lloyd, David R; Medina, Douglas J; Hawk, Larry W; Fosco, Whitney D; Richards, Jerry B

    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 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 etal., 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. PMID:24409128

  14. Thermally Activated Retainers For Insertion In Gaps

    NASA Technical Reports Server (NTRS)

    Grimaldi, Margaret E.; Hartz, Leslie S.

    1992-01-01

    Mechanical retainers of new type for use with gap filler easy to install and to attach themselves securely. Concept based on shape-memory properties of metal alloy Nitinol, alloy of nickel and titanium. Retainers conceived for use with Space Shuttle insulating tiles but used on other assemblies of blocks or tiles configured similarly. Tabs bent outward made flush by cooling below memory transition temperature. After insertion in gap and reheating, tabs spring outward.

  15. Fiber reinforced hybrid phenolic foam

    NASA Astrophysics Data System (ADS)

    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. Guideline Implementation: Prevention of Retained Surgical Items.

    PubMed

    Fencl, Jennifer L

    2016-07-01

    A surgical item unintentionally retained in a patient after an operative or other invasive procedure is a serious, preventable medical error with the potential to cause the patient great harm. Perioperative RNs play a key role in preventing retained surgical items (RSIs). The updated AORN "Guideline for prevention of retained surgical items" provides guidance for implementing a consistent, multidisciplinary approach to RSI prevention; accounting for surgical items; preventing retention of device fragments; reconciling count discrepancies; and using adjunct technologies to supplement manual count procedures. This article focuses on key points of the guideline to help perioperative personnel provide optimal care during a procedure. Key points addressed include taking responsibility for RSI prevention as a team; minimizing distractions, noise, and interruptions during counts; using consistent counting methods; reconciling discrepancies; and participating in performance-improvement activities. Perioperative RNs should review the complete guideline for additional information and for guidance in writing and updating policies and procedures. PMID:27350354

  17. Acquisition and Retaining Granular Samples via a Rotating Coring Bit

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Badescu, Mircea; Sherrit, Stewart

    2013-01-01

    This device takes advantage of the centrifugal forces that are generated when a coring bit is rotated, and a granular sample is entered into the bit while it is spinning, making it adhere to the internal wall of the bit, where it compacts itself into the wall of the bit. The bit can be specially designed to increase the effectiveness of regolith capturing while turning and penetrating the subsurface. The bit teeth can be oriented such that they direct the regolith toward the bit axis during the rotation of the bit. The bit can be designed with an internal flute that directs the regolith upward inside the bit. The use of both the teeth and flute can be implemented in the same bit. The bit can also be designed with an internal spiral into which the various particles wedge. In another implementation, the bit can be designed to collect regolith primarily from a specific depth. For that implementation, the bit can be designed such that when turning one way, the teeth guide the regolith outward of the bit and when turning in the opposite direction, the teeth will guide the regolith inward into the bit internal section. This mechanism can be implemented with or without an internal flute. The device is based on the use of a spinning coring bit (hollow interior) as a means of retaining granular sample, and the acquisition is done by inserting the bit into the subsurface of a regolith, soil, or powder. To demonstrate the concept, a commercial drill and a coring bit were used. The bit was turned and inserted into the soil that was contained in a bucket. While spinning the bit (at speeds of 600 to 700 RPM), the drill was lifted and the soil was retained inside the bit. To prove this point, the drill was turned horizontally, and the acquired soil was still inside the bit. The basic theory behind the process of retaining unconsolidated mass that can be acquired by the centrifugal forces of the bit is determined by noting that in order to stay inside the interior of the bit, the

  18. Reinforced plastics durability

    SciTech Connect

    Pritchard, G.

    1999-01-01

    Written especially for first-time users of reinforced plastics. The book offers substantial introductory information with key concepts. Chapters examine the long-term threats to the integrity of reinforced plastics: outdoor weathering, solvent/water attack, high temperatures, and repetitive stress.

  19. Ammonia Results Review for Retained Gas Sampling

    SciTech Connect

    Mahoney, Lenna A.

    2000-09-20

    This report was prepared as part of a task supporting the deployment of the retained gas sampler (RGS) system in Flammable Gas Watch List Tanks. The emphasis of this report is on presenting supplemental information about the ammonia measurements resulting from retained gas sampling of Tanks 241-AW-101, A-101, AN-105, AN-104, AN-103, U-103, S-106, BY-101, BY-109, SX-106, AX-101, S-102, S-111, U-109, and SY-101. This information provides a better understanding of the accuracy of past RGS ammonia measurements, which will assist in determining flammable and toxicological hazards.

  20. Composite Intersection Reinforcement

    NASA Technical Reports Server (NTRS)

    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.

  1. Composite intersection reinforcement

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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.

  2. Retaining African Americans in Higher Education: Challenging Paradigms for Retaining Students, Faculty and Administrators.

    ERIC Educational Resources Information Center

    Jones, Lee, Ed.

    This collection discusses some of the issues surrounding the retention of African Americans in higher education, and it challenges traditional paradigms for retaining African American students, administrators, and faculty at predominantly White colleges. The chapters of part 1, "Retaining African-American Students," are: (1) "Creating an Affirming…

  3. Retaining Excellent Teachers through Effective Leadership

    ERIC Educational Resources Information Center

    Le, Connie

    2013-01-01

    School districts continue to face challenges in retaining talented teachers in their schools. There are many factors that contribute to teacher retention, including working conditions, a lack of leadership support, and poor leadership behavior. In a southeastern U.S. state, local school officials were seeking strategies to provide an excellent…

  4. Retained gas sampler system acceptance test report

    SciTech Connect

    Cannon, N.S., Westinghouse Hanford

    1996-07-18

    Acceptance test results for the Retained Gas Sampler System (RGSS) obtained in the 306E laboratory are reported. The RGSS will be utilized to retrieve and analyze samples from the Hanford flammable gas watch-list tanks to determine the quantity and chemistry of gases confined within the waste.

  5. Retained Gas Sampler Calibration and Simulant Tests

    SciTech Connect

    CRAWFORD, B.A.

    2000-01-05

    This test plan provides a method for calibration of the retained gas sampler (RGS) for ammonia gas analysis. Simulant solutions of ammonium hydroxide at known concentrations will be diluted with isotopically labeled 0.04 M ammonium hydroxide solution. Sea sand solids will also be mixed with ammonium hydroxide solution and diluent to determine the accuracy of the system for ammonia gas analysis.

  6. Stragegies for Attracting and Retaining Teachers

    ERIC Educational Resources Information Center

    Bland, Paul; Church, Edwin; Luo, Mingchu

    2014-01-01

    Attracting and retaining high quality teachers is a challenge for many school districts. This is especially true in a time of increased accountability and limited resources. This report details best practice in the training, hiring, improvement, and retention of high quality teaching staff. The authors explain how school leaders can attract…

  7. 45 CFR 1611.9 - Retainer agreements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... to the client or for legal services provided to the client by a private attorney pursuant to 45 CFR... 45 Public Welfare 4 2010-10-01 2010-10-01 false Retainer agreements. 1611.9 Section 1611.9 Public Welfare Regulations Relating to Public Welfare (Continued) LEGAL SERVICES CORPORATION...

  8. Selecting and Retaining Teacher Mentors. ERIC Digest.

    ERIC Educational Resources Information Center

    Mullinix, Bonnie B.

    This digest examines considerations and strategies for selecting and retaining teacher mentors, suggesting that the degree to which mentors are meaningfully engaged in the mentoring process may have a significant impact on a program's success. Strategies for recruiting mentors range from opportunistic appointment to promoting self-nomination to…

  9. Reteniendo los directores (Retaining Principals). ERIC Digest.

    ERIC Educational Resources Information Center

    Hertling, Elizabeth

    This digest in Spanish examines the reasons why--outside of retirement--school principals leave their jobs. It also lists strategies districts can employ to retain principals. Many principals exit their profession because of the long hours, the workload and complexity of the job, the unending supervision of evening activities, the minimal pay…

  10. Recruiting, Retaining, and Fairly Compensating Our Teachers

    ERIC Educational Resources Information Center

    Lynch, Matthew

    2012-01-01

    This article examines three interlinked problems facing public schools today: how to recruit, retain, and pay our teachers. The article begins with an overview of the current situation in the United States, paying particular attention to schools in areas where minorities are the majority. It goes on to examine some of the causes of teacher…

  11. Reinforced concrete offshore platform

    SciTech Connect

    Martyshenko, J.P.; Martyshenko, S.J.; Kotelnikov, J.S.; Kutukhtin, E.G.; Petrosian, M.S.; Ilyasova, N.I.; Volkov, J.S.; Vardanian, A.M.

    1987-10-20

    A reinforced concrete offshore platform is described comprising a honeycomb foundation (A), a supporting structure (B) and an above-surface section (C) carrying appropriate equipment. The honeycomb foundation (A) and the supporting structure (B) are made of prefabricated reinforced concrete elements which are polyhedral hollow prisms arranged with gaps between the external sides thereof and joined by a system of prestressed vertical diaphragm walls and horizontal diaphragm walls formed by pre-tensioning reinforcing bars placed in the gaps between the faces of the prisms and casting in-situ the gaps later on.

  12. Fire test method for graphite fiber reinforced plastics

    NASA Technical Reports Server (NTRS)

    Bowles, K. J.

    1980-01-01

    A potential problem in the use of graphite fiber reinforced resin matrix composites is the dispersal of graphite fibers during accidential fires. Airborne, electrically conductive fibers originating from the burning composites could enter and cause shorting in electrical equipment located in surrounding areas. A test method for assessing the burning characteristics of graphite fiber reinforced composites and the effectiveness of the composites in retaining the graphite fibers has been developed. The method utilizes a modified rate of heat release apparatus. The equipment and the testing procedure are described. The application of the test method to the assessment of composite materials is illustrated for two resin matrix/graphite composite systems.

  13. Fire test method for graphite fiber reinforced plastics

    NASA Technical Reports Server (NTRS)

    Bowles, K. J.

    1980-01-01

    A potential problem in the use of graphite fiber reinforced resin matrix composites is the dispersal of graphite fibers during accidental fires. Airborne, electrically conductive fibers originating from the burning composites could enter and cause shorting in electrical equipment located in surrounding areas. A test method for assessing the burning characteristics of graphite fiber reinforced composites and the effectiveness of the composites in retaining the graphite fibers has been developed. The method utilizes a modified Ohio State University Rate of Heat Release apparatus. The equipment and the testing procedure are described. The application of the test method to the assessment of composite materials is illustrated for two resin matrix/graphite composite systems.

  14. Fibre-reinforced materials.

    PubMed

    Brown, D

    2000-11-01

    This paper considers the role of fibres in the reinforcement of composite materials, and the significance of the form the fibre takes and the material from which it is made. The current dental applications of fibre reinforcement, including dental cements and splints, fibres made into structures for use in composites, denture bases and the contemporary use of fibres in fixed partial dentures, are reviewed. Their role in biomedical implants is surveyed and their future forecast. PMID:11218597

  15. Reinforcement learning in scheduling

    NASA Technical Reports Server (NTRS)

    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.

  16. 9 CFR 441.10 - Retained water.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... standard for Salmonella as set forth in the PR/HACCP regulations (9 CFR 310.25(b), 381.94(b)) and the time/temperature requirements set forth in 9 CFR 381.66. Additional purposes that could be included are determining... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Retained water. 441.10 Section...

  17. 9 CFR 441.10 - Retained water.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... standard for Salmonella as set forth in the PR/HACCP regulations (9 CFR 310.25(b), 381.94(b)) and the time/temperature requirements set forth in 9 CFR 381.66. Additional purposes that could be included are determining... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Retained water. 441.10 Section...

  18. 9 CFR 441.10 - Retained water.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... standard for Salmonella as set forth in the PR/HACCP regulations (9 CFR 310.25(b), 381.94(b)) and the time/temperature requirements set forth in 9 CFR 381.66. Additional purposes that could be included are determining... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Retained water. 441.10 Section...

  19. 9 CFR 441.10 - Retained water.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... standard for Salmonella as set forth in the PR/HACCP regulations (9 CFR 310.25(b), 381.94(b)) and the time/temperature requirements set forth in 9 CFR 381.66. Additional purposes that could be included are determining... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Retained water. 441.10 Section...

  20. 9 CFR 441.10 - Retained water.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... standard for Salmonella as set forth in the PR/HACCP regulations (9 CFR 310.25(b), 381.94(b)) and the time/temperature requirements set forth in 9 CFR 381.66. Additional purposes that could be included are determining... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Retained water. 441.10 Section...

  1. Retaining nursing faculty beyond retirement age.

    PubMed

    Williamson, Marvel L; Cook, Linda; Salmeron, Lois; Burton, Denise

    2010-01-01

    The number of nursing faculty planning to retire by 2020 is alarming. To develop strategies for retaining faculty, researchers asked: What factors influence the decision by nursing faculty to stay in the workforce past retirement age? What barriers could be removed that would encourage faculty to stay longer? Using Giorgi's analysis method, findings from 6 faculty teaching past retirement age revealed key meaning units and grand themes that match Maslow's Hierarchy of Inborn Needs. PMID:20548182

  2. The substitutability of reinforcers

    PubMed Central

    Green, Leonard; Freed, Debra E.

    1993-01-01

    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

  3. The substitutability of reinforcers.

    PubMed

    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

  4. Dynamic response of cantilever retaining walls

    SciTech Connect

    Veletsos, A.S.; Younan, A.H.; Bandyopadhyay, K.

    1996-10-01

    A critical evaluation is made of the response to horizontal ground shaking of flexible cantilever retaining walls that are elastically constrained against rotation at their base. The retained medium is idealized as a uniform, linear, viscoelastic stratum of constant thickness and semi-infinite extent in the horizontal direction. The parameters varied include the flexibilities of the wall and its base, the properties of the retained medium, and the characteristics of the ground motion. In addition to long-period, effectively static excitations, both harmonic base motions and an actual earthquake record are considered. The response quantities examined include the displacements of the wall relative to the moving base, the wall pressures, and the associated shears and bending moments. The method of analysis employed is described only briefly, emphasis being placed on the presentation and interpretation of the comprehensive numerical solutions. It is shown that, for realistic wall flexibilities, the maximum wall forces are significantly lower than those obtained for fixed-based rigid walls and potentially of the same order of magnitude as those computed by the Mononobe-Okabe method.

  5. Retaining latch for a water pit gate

    DOEpatents

    Beale, A.R.

    1997-11-18

    A retaining latch is described for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame. 4 figs.

  6. Root canal retained restorations: 1. General considerations and custom-made cast posts and cores.

    PubMed

    Edmunds, D H; Dummer, P M

    1990-06-01

    The first article in this series reviews general considerations relating to the use of root canal retained restorations. The authors discuss factors affecting retention, the arguments for cast versus wrought posts, reinforcement of the tooth, and treatment planning. Clinical procedures for constructing custom-made cast posts and cores, using direct and indirect techniques, are also described. The three subsequent articles will deal with threaded and unthreaded prefabricated post-and-core systems, and root-face attachments for the retention of complete and partial overdentures. PMID:2079151

  7. Every reinforcer counts: reinforcer magnitude and local preference.

    PubMed Central

    Davison, Michael; Baum, William M

    2003-01-01

    Six pigeons were trained on concurrent variable-interval schedules. Sessions consisted of seven components, each lasting 10 reinforcers, with the conditions of reinforcement differing between components. The component sequence was randomly selected without replacement. In Experiment 1, the concurrent-schedule reinforcer ratios in components were all equal to 1.0, but across components reinforcer-magnitude ratios varied from 1:7 through 7:1. Three different overall reinforcer rates were arranged across conditions. In Experiment 2, the reinforcer-rate ratios varied across components from 27:1 to 1:27, and the reinforcer-magnitude ratios for each alternative were changed across conditions from 1:7 to 7:1. The results of Experiment 1 replicated the results for changing reinforcer-rate ratios across components reported by Davison and Baum (2000, 2002): Sensitivity to reinforcer-magnitude ratios increased with increasing numbers of reinforcers in components. Sensitivity to magnitude ratio, however, fell short of sensitivity to reinforcer-rate ratio. The degree of carryover from component to component depended on the reinforcer rate. Larger reinforcers produced larger and longer postreinforcer preference pulses than did smaller reinforcers. Similar results were found in Experiment 2, except that sensitivity to reinforcer magnitude was considerably higher and was greater for magnitudes that differed more from one another. Visit durations following reinforcers measured either as number of responses emitted or time spent responding before a changeover were longer following larger than following smaller reinforcers, and were longer following sequences of same reinforcers than following other sequences. The results add to the growing body of research that informs model building at local levels. PMID:13677611

  8. BEHAVIOR OF METALS IN SOILS

    EPA Science Inventory

    Metals added to soil will normally be retained at the soil surface. ovement of metals into other environmental compartments, i.e. groundwater, surface water, or the atmosphere, should be minimal as long as the retention capacity of the soil is not exceeded. he extent of movement ...

  9. Fiber-reinforced glass

    SciTech Connect

    Beier, W.; Markman, S.

    1997-12-01

    Fiber-reinforced glass composites are glass or glass ceramic matrices reinforced with long fibers of carbon or silicon carbide. These composites are lighter than steel but just as strong as many steel grades, and can resist higher temperatures. They also have outstanding resistance to impact, thermal shock, and wear, and can be formulated to control thermal and electrical conductivity. With proper tooling, operations such as drilling, grinding, and turning can be completed in half the time required for non-reinforced glass. Currently, fiber-reinforced glass components are primarily used for handling hot glass or molten aluminum during manufacturing operations. But FRG is also under test as an engineering material in a variety of markets, including the aerospace, automotive, and semiconductor industries. Toward this end, research is being carried out to increase the size of components that can be delivered on a production basis, to develop economical methods of achieving complex near-net shapes, and to reduce the cycle time for production of specific shapes. This article focuses on the properties and applications of fiber-reinforced glass composites.

  10. Retaining Device For One-Piece Battery

    DOEpatents

    Gilabert, Claude; Leturque, Michel; Verhoog, Roclof

    2000-08-01

    The present invention consists of a device for retaining a one-piece battery with a prismatic casing having two longitudinal walls and two transverse walls. The device contains two plates applied to respective transverse walls and at least one cinching mechanism for the plates consisting of at least one flat strip closed on itself surrounding the longitudinal walls and the transverse walls are provided with the plates. The device is characterized in that at least one of the plates contains at least one recessed housing and the strip closely follows the shape of the housing.

  11. Self Retaining Anti-Rotation Key

    NASA Technical Reports Server (NTRS)

    Dixon, Alan Benjamin Christopher (Inventor)

    2015-01-01

    Anti-rotation keys are typically used in applications where an end of a threaded stud is received in a housing, and where the opposite end of the stud projects from the housing to allow attachment of another component to the housing. Once partially received in the housing, further rotation of the stud is prevented by an anti-rotation key. The disclosed anti-rotation key is self-retaining, in that it prevents itself from "backing out" of the channel due to vibration or thermal expansion of the housing, etc., while also being removable from the channel if desired.

  12. Evaluating The Influence of Postsession Reinforcement on Choice of Reinforcers

    PubMed Central

    Kodak, Tiffany; Lerman, Dorothea C; Call, Nathan

    2007-01-01

    Factors that influence reinforcer choice have been examined in a number of applied studies (e.g., Neef, Mace, Shea, & Shade, 1992; Shore, Iwata, DeLeon, Kahng, & Smith, 1997; Tustin, 1994). However, no applied studies have evaluated the effects of postsession reinforcement on choice between concurrently available reinforcers, even though basic findings indicate that this is an important factor to consider (Hursh, 1978; Zeiler, 1999). In this bridge investigation, we evaluated the influence of postsession reinforcement on choice of two food items when task responding was reinforced on progressive-ratio schedules. Participants were 3 children who had been diagnosed with developmental disabilities. Results indicated that response allocation shifted from one food item to the other food item under thinner schedules of reinforcement when no postsession reinforcement was provided. These findings suggest that the efficacy of instructional programs or treatments for problem behavior may be improved by restricting reinforcers outside treatment sessions. PMID:17970264

  13. History of reinforced plastics

    SciTech Connect

    Milewski, J.V.; Rosato, D.V.

    1981-01-01

    This history of reinforced plastics is told by combining the individual histories of each reinforcement and the way in which they added to and changed the direction and rate of growth of the industry. The early history is based on all resins, fillers, and fibers found in nature. Then came the Baekeland revolution with the first synthetic resin which lasted about 25 years, at which time synthetic fiber glass and polyester resin dramatically changed the industry. Now, for the 1980s, the high modulus fibers developed 10 to 20 years ago are reshaping the industry. 32 figures.

  14. Reinforcement of hydrogels using three-dimensionally printed microfibres.

    PubMed

    Visser, Jetze; Melchels, Ferry P W; Jeon, June E; van Bussel, Erik M; Kimpton, Laura S; Byrne, Helen M; Dhert, Wouter J A; Dalton, Paul D; Hutmacher, Dietmar W; Malda, Jos

    2015-01-01

    Despite intensive research, hydrogels currently available for tissue repair in the musculoskeletal system are unable to meet the mechanical, as well as the biological, requirements for successful outcomes. Here we reinforce soft hydrogels with highly organized, high-porosity microfibre networks that are 3D-printed with a technique termed as melt electrospinning writing. We show that the stiffness of the gel/scaffold composites increases synergistically (up to 54-fold), compared with hydrogels or microfibre scaffolds alone. Modelling affirms that reinforcement with defined microscale structures is applicable to numerous hydrogels. The stiffness and elasticity of the composites approach that of articular cartilage tissue. Human chondrocytes embedded in the composites are viable, retain their round morphology and are responsive to an in vitro physiological loading regime in terms of gene expression and matrix production. The current approach of reinforcing hydrogels with 3D-printed microfibres offers a fundament for producing tissue constructs with biological and mechanical compatibility. PMID:25917746

  15. Reinforcement of hydrogels using three-dimensionally printed microfibres

    NASA Astrophysics Data System (ADS)

    Visser, Jetze; Melchels, Ferry P. W.; Jeon, June E.; van Bussel, Erik M.; Kimpton, Laura S.; Byrne, Helen M.; Dhert, Wouter J. A.; Dalton, Paul D.; Hutmacher, Dietmar W.; Malda, Jos

    2015-04-01

    Despite intensive research, hydrogels currently available for tissue repair in the musculoskeletal system are unable to meet the mechanical, as well as the biological, requirements for successful outcomes. Here we reinforce soft hydrogels with highly organized, high-porosity microfibre networks that are 3D-printed with a technique termed as melt electrospinning writing. We show that the stiffness of the gel/scaffold composites increases synergistically (up to 54-fold), compared with hydrogels or microfibre scaffolds alone. Modelling affirms that reinforcement with defined microscale structures is applicable to numerous hydrogels. The stiffness and elasticity of the composites approach that of articular cartilage tissue. Human chondrocytes embedded in the composites are viable, retain their round morphology and are responsive to an in vitro physiological loading regime in terms of gene expression and matrix production. The current approach of reinforcing hydrogels with 3D-printed microfibres offers a fundament for producing tissue constructs with biological and mechanical compatibility.

  16. Cement-retained versus screw-retained implant restorations: a critical review.

    PubMed

    Michalakis, Konstantinos X; Hirayama, Hiroshi; Garefis, Pavlos D

    2003-01-01

    This article presents a comparison of screw-retained and cement-retained implant prostheses based on the literature. The advantages, disadvantages, and limitations of the 2 different types of restorations are discussed, because it is important to understand the influence of the attachment mechanism on many clinical aspects of implant dentistry. Several factors essential to the long-term success of any implant prosthesis were reviewed with regard to both methods of fixation. These factors include: (1) ease of fabrication and cost, (2) passivity of the framework, (3) retention, (4) occlusion, (5) esthetics, (6) delivery, and (7) retrievability. (More than 50 references). PMID:14579961

  17. Evaluating the Influence of Postsession Reinforcement on Choice of Reinforcers

    ERIC Educational Resources Information Center

    Kodak, Tiffany; Lerman, Dorothea C.; Call, Nathan

    2007-01-01

    Factors that influence reinforcer choice have been examined in a number of applied studies (e.g., Neef, Mace, Shea, & Shade, 1992; Shore, Iwata, DeLeon, Kahng, & Smith, 1997; Tustin, 1994). However, no applied studies have evaluated the effects of postsession reinforcement on choice between concurrently available reinforcers, even though basic…

  18. Reinforcement Magnitude: An Evaluation of Preference and Reinforcer Efficacy

    ERIC Educational Resources Information Center

    Trosclair-Lasserre, Nicole M.; Lerman, Dorothea C.; Call, Nathan A.; Addison, Laura R.; Kodak, Tiffany

    2008-01-01

    Consideration of reinforcer magnitude may be important for maximizing the efficacy of treatment for problem behavior. Nonetheless, relatively little is known about children's preferences for different magnitudes of social reinforcement or the extent to which preference is related to differences in reinforcer efficacy. The purpose of the current…

  19. Waterfowl density on agricultural fields managed to retain water in winter

    USGS Publications Warehouse

    Twedt, D.J.; Nelms, C.O.

    1999-01-01

    Managed water on private and public land provides habitat for wintering waterfowl in the Mississippi Valley, where flood control projects have reduced the area of natural flooding. We compared waterfowl densities on rice, soybean, and moist-soil fields under cooperative agreements to retain water from 1 November through 28 February in Arkansas and Mississippi and assessed temporal changes in waterfowl density during winter in 1991-1992 and 1992-1993. Fields flooded earlier in Arkansas, but retained water later in Mississippi. Over winter, waterfowl densities decreased in Arkansas and increased in Mississippi. Densities of waterfowl, including mallard (Anas platyrhynchos), the most abundant species observed, were greatest on moist-soil fields. However, soybean fields had the greatest densities of northern shoveler (Spatula clypeata).

  20. Oscillations following periodic reinforcement.

    PubMed

    Monteiro, Tiago; Machado, Armando

    2009-06-01

    Three experiments examined behavior in extinction following periodic reinforcement. During the first phase of Experiment 1, four groups of pigeons were exposed to fixed interval (FI 16s or FI 48s) or variable interval (VI 16s or VI 48s) reinforcement schedules. Next, during the second phase, each session started with reinforcement trials and ended with an extinction segment. Experiment 2 was similar except that the extinction segment was considerably longer. Experiment 3 replaced the FI schedules with a peak procedure, with FI trials interspersed with non-food peak interval (PI) trials that were four times longer. One group of pigeons was exposed to FI 20s PI 80s trials, and another to FI 40s PI 160s trials. Results showed that, during the extinction segment, most pigeons trained with FI schedules, but not with VI schedules, displayed pause-peck oscillations with a period close to, but slightly greater than the FI parameter. These oscillations did not start immediately after the onset of extinction. Comparing the oscillations from Experiments 1 and 2 suggested that the alternation of reconditioning and re-extinction increases the reliability and earlier onset of the oscillations. In Experiment 3 the pigeons exhibited well-defined pause-peck cycles since the onset of extinction. These cycles had periods close to twice the value of the FI and lasted for long intervals of time. We discuss some hypotheses concerning the processes underlying behavioral oscillations following periodic reinforcement. PMID:18992793

  1. Reinforcing Saccadic Amplitude Variability

    ERIC Educational Resources Information Center

    Paeye, Celine; Madelain, Laurent

    2011-01-01

    Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we…

  2. Chromosomally-retained RNA mediates homologous pairing.

    PubMed

    Ding, Da-Qiao; Haraguchi, Tokuko; Hiraoka, Yasushi

    2012-01-01

    Pairing and recombination of homologous chromosomes are essential for ensuring correct segregation of chromosomes in meiosis. In S. pombe, chromosomes are first bundled at the telomeres (forming a telomere bouquet) and then aligned by oscillatory movement of the elongated "horsetail" nucleus. Telomere clustering and subsequent chromosome alignment promote pairing of homologous chromosomes. However, this telomere-bundled alignment of chromosomes cannot be responsible for the specificity of chromosome pairing. Thus, there must be some mechanism to facilitate recognition of homologous partners after telomere clustering. Recent studies in S. pombe have shown that RNA transcripts retained on the chromosome, or RNA bodies, may play a role in recognition of homologous chromosomes for pairing. Acting as fiducial markers of homologous loci they would abrogate the need for direct DNA sequence homology searching. PMID:23117617

  3. Recruiting and retaining indigenous farmworker participants.

    PubMed

    Farquhar, Stephanie; de Jesus Gonzalez, Carmen; Hall, Jennifer; Samples, Julie; Ventura, Santiago; Sanchez, Valentin; Shadbeh, Nargess

    2014-10-01

    There is limited information on the specific practices used to successfully recruit and retain indigenous and Latino farmworkers in research studies. This article describes the strategies used in a community-based participatory research project with indigenous agricultural workers. Participants were recruited through consulting with indigenous relatives and friends, identifying and meeting with indigenous leaders from hometown associations in countries of origin, and asking current participants to recruit fellow farmworkers. Adjustments were initiated to the second year protocol to enhance recruitment and retention. The difference in attrition rates between years one and two was statistically significant, a difference partially attributed to modifications to recruitment and retention protocol. Findings confirmed that active recruitment techniques and word-of-mouth recruitment were more effective than passive methods. Trust among academic, organization, and community partners, and shared language and culture between those doing the recruitment and the participants, contributed to sustained farmworker participation. PMID:23733354

  4. Recruiting and retaining indigenous farmworker participants

    PubMed Central

    Farquhar, Stephanie; de Jesus Gonzalez, Carmen; Hall, Jennifer; Samples, Julie; Ventura, Santiago; Sanchez, Valentin; Shadbeh, Nargess

    2013-01-01

    There is limited information on the specific practices used to successfully recruit and retain indigenous and Latino farmworkers in research studies. This article describes the strategies used in a community-based participatory research project with indigenous agricultural workers. Participants were recruited through consulting with indigenous relatives and friends, identifying and meeting with indigenous leaders from hometown associations in countries of origin, and asking current participants to recruit fellow farmworkers. Adjustments were initiated to the second year protocol to enhance recruitment and retention. The difference in attrition rates between years one and two was statistically significant, a difference partially attributed to modifications to recruitment and retention protocol. Findings confirmed that active recruitment techniques and word-of-mouth recruitment were more effective than passive methods. Trust among academic, organization, and community partners, and shared language and culture between those doing the recruitment and the participants, contributed to sustained farmworker participation. PMID:23733354

  5. Quasicrystalline particulate reinforced aluminum composite

    SciTech Connect

    Anderson, I.E.; Biner, S.B.; Sordelet, D.J.; Unal, O.

    1997-07-01

    Particulate reinforced aluminum and aluminum alloy composites are rapidly emerging as new commercial materials for aerospace, automotive, electronic packaging and other high performance applications. However, their low processing ductility and difficulty in recyclability have been the key concern. In this study, two composite systems having the same aluminum alloy matrix, one reinforced with quasicrystals and the other reinforced with the conventional SiC reinforcements were produced with identical processing routes. Their processing characteristics and tensile mechanical properties were compared.

  6. Matching and Conditioned Reinforcement Rate

    ERIC Educational Resources Information Center

    Shahan, Timothy A.; Podlesnik, Christopher A.; Jimenez-Gomez, Corina

    2006-01-01

    Attempts to examine the effects of variations in relative conditioned reinforcement rate on choice have been confounded by changes in rates of primary reinforcement or changes in the value of the conditioned reinforcer. To avoid these problems, this experiment used concurrent observing responses to examine sensitivity of choice to relative…

  7. Al-based metal matrix composites reinforced with nanocrystalline Al-Ti-Ni particles

    NASA Astrophysics Data System (ADS)

    Scudino, S.; Ali, F.; Surreddi, K. B.; Prashanth, K. G.; Sakaliyska, M.; Eckert, J.

    2010-07-01

    Al-based metal matrix composites containing different volume fractions of nanocrystalline Al70Ti20Ni10 reinforcing particles have been produced by powder metallurgy and the effect of the volume fraction of reinforcement on the mechanical properties of the composites has been studied. Room temperature compression tests reveal a considerable improvement of the mechanical properties as compared to pure Aluminum. The compressive strength increases from 155 MPa for pure Al to about 200 and 240 MPa for the samples with 20 and 40 vol.% of reinforcement, respectively, while retaining appreciable plastic deformation with a fracture strain ranging between 43 and 28 %.

  8. Autoshaping Chicks with Heat Reinforcement: The Role of Stimulus-Reinforcer and Response-Reinforcer Relations

    ERIC Educational Resources Information Center

    Wasserman, Edward A.; And Others

    1975-01-01

    The present series of experiments attempted to analyze more fully the contributions of stimulus-reinforcer and response-reinforcer relations to autoshaping within a single conditioning situation. (Author)

  9. 30 CFR 47.55 - Retaining an MSDS.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Retaining an MSDS. 47.55 Section 47.55 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING HAZARD COMMUNICATION (HazCom) Material Safety Data Sheets (MSDS) § 47.55 Retaining an MSDS. The operator must— (a) Retain its MSDS for as long as...

  10. 13 CFR 120.1707 - Seller's retained Loan Interest.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Establishment of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1707 Seller's retained Loan Interest. The Seller must retain a 15% or greater Loan Interest in each of its loans...'s retained ownership in the Pool Loan. With SBA's written permission, the Seller may sell the...

  11. 30 CFR 47.55 - Retaining an MSDS.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Retaining an MSDS. 47.55 Section 47.55 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING HAZARD COMMUNICATION (HazCom) Material Safety Data Sheets (MSDS) § 47.55 Retaining an MSDS. The operator must— (a) Retain its MSDS for as long as...

  12. 30 CFR 47.55 - Retaining an MSDS.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Retaining an MSDS. 47.55 Section 47.55 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING HAZARD COMMUNICATION (HazCom) Material Safety Data Sheets (MSDS) § 47.55 Retaining an MSDS. The operator must— (a) Retain its MSDS for as long as...

  13. 30 CFR 47.55 - Retaining an MSDS.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Retaining an MSDS. 47.55 Section 47.55 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING HAZARD COMMUNICATION (HazCom) Material Safety Data Sheets (MSDS) § 47.55 Retaining an MSDS. The operator must— (a) Retain its MSDS for as long as...

  14. 30 CFR 47.55 - Retaining an MSDS.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Retaining an MSDS. 47.55 Section 47.55 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING HAZARD COMMUNICATION (HazCom) Material Safety Data Sheets (MSDS) § 47.55 Retaining an MSDS. The operator must— (a) Retain its MSDS for as long as...

  15. 5 CFR 531.241 - Retaining and losing GM status.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... retained rate under 5 CFR part 536. (A retained grade is not considered in determining whether a GM employee has been reduced in grade. See 5 CFR 536.205.) ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Retaining and losing GM status....

  16. A nanostructured carbon-reinforced polyisobutylene-based thermoplastic elastomer.

    PubMed

    Puskas, Judit E; Foreman-Orlowski, Elizabeth A; Lim, Goy Teck; Porosky, Sara E; Evancho-Chapman, Michelle M; Schmidt, Steven P; El Fray, Mirosława; Piatek, Marta; Prowans, Piotr; Lovejoy, Krystal

    2010-03-01

    This paper presents the synthesis and characterization of a polyisobutylene (PIB)-based nanostructured carbon-reinforced thermoplastic elastomer. This thermoplastic elastomer is based on a self-assembling block copolymer having a branched PIB core carrying -OH functional groups at each branch point, flanked by blocks of poly(isobutylene-co-para-methylstyrene). The block copolymer has thermolabile physical crosslinks and can be processed as a plastic, yet retains its rubbery properties at room temperature. The carbon-reinforced thermoplastic elastomer had more than twice the tensile strength of the neat polymer, exceeding the strength of medical grade silicone rubber, while remaining significantly softer. The carbon-reinforced thermoplastic elastomer displayed a high T(g) of 126 degrees C, rendering the material steam-sterilizable. The carbon also acted as a free radical trap, increasing the onset temperature of thermal decomposition in the neat polymer from 256.6 degrees C to 327.7 degrees C. The carbon-reinforced thermoplastic elastomer had the lowest water contact angle at 82 degrees and surface nano-topography. After 180 days of implantation into rabbit soft tissues, the carbon-reinforced thermoplastic elastomer had the thinnest tissue capsule around the microdumbbell specimens, with no eosinophiles present. The material also showed excellent integration into bones. PMID:20034664

  17. Grass plants bind, retain, uptake, and transport infectious prions.

    PubMed

    Pritzkow, Sandra; Morales, Rodrigo; Moda, Fabio; Khan, Uffaf; Telling, Glenn C; Hoover, Edward; Soto, Claudio

    2015-05-26

    Prions are the protein-based infectious agents responsible for prion diseases. Environmental prion contamination has been implicated in disease transmission. Here, we analyzed the binding and retention of infectious prion protein (PrP(Sc)) to plants. Small quantities of PrP(Sc) contained in diluted brain homogenate or in excretory materials (urine and feces) can bind to wheat grass roots and leaves. Wild-type hamsters were efficiently infected by ingestion of prion-contaminated plants. The prion-plant interaction occurs with prions from diverse origins, including chronic wasting disease. Furthermore, leaves contaminated by spraying with a prion-containing preparation retained PrP(Sc) for several weeks in the living plant. Finally, plants can uptake prions from contaminated soil and transport them to aerial parts of the plant (stem and leaves). These findings demonstrate that plants can efficiently bind infectious prions and act as carriers of infectivity, suggesting a possible role of environmental prion contamination in the horizontal transmission of the disease. PMID:25981035

  18. Grass plants bind, retain, uptake and transport infectious prions

    PubMed Central

    Pritzkow, Sandra; Morales, Rodrigo; Moda, Fabio; Khan, Uffaf; Telling, Glenn C.; Hoover, Edward; Soto, Claudio

    2015-01-01

    Prions are the protein-based infectious agents responsible for prion diseases. Environmental prion contamination has been implicated in disease transmission. Here we analyzed the binding and retention of infectious prion protein (PrPSc) to plants. Small quantities of PrPSc contained in diluted brain homogenate or in excretory materials (urine and feces) can bind to wheat grass roots and leaves. Wild type hamsters were efficiently infected by ingestion of prion-contaminated plants. The prion-plant interaction occurs with prions from diverse origins, including chronic wasting disease. Furthermore, leaves contaminated by spraying with a prion-containing preparation retained PrPSc for several weeks in the living plant. Finally, plants can uptake prions from contaminated soil and transport them to aerial parts of the plant (stem and leaves). These findings demonstrate that plants can efficiently bind infectious prions and act as carriers of infectivity, suggesting a possible role of environmental prion contamination in the horizontal transmission of the disease. PMID:25981035

  19. Nanostructured composite reinforced material

    DOEpatents

    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.

  20. Dynamic response of flexible retaining walls

    SciTech Connect

    Younan, A.H.; Veletsos, A.S.; Bandyopadhyay, K.

    1997-01-01

    Making use of an extension of a recently proposed, relatively simple, approximate method of analysis, a critical evaluation is made of the response to horizontal ground shaking of flexible walls retaining a uniform, linear, viscoelastic stratum of constant thickness and semiinfinite extent in the horizontal direction. Both cantilever and top-supported walls are examined. Following a detailed description of the method and of its rate of convergence, comprehensive numerical solutions are presented that elucidate the action of the system and the effects of the various parameters involved. The parameters varied include the flexibility of the wall, the condition of top support, and the characteristics of the ground motion. The effects of both harmonic base motions and an actual earthquake record are examined. Special attention is paid to the effects of long-period, effectively static excitations. A maximum dynamic response is then expressed as the product of the corresponding static response and an appropriate amplification or deamplification factor. The response quantities examined include the displacements of the wall relative to the moving base, the dynamic wall pressures, and the total wall force, base shear and base moment.

  1. Reinforcement Learning Trees

    PubMed Central

    Zhu, Ruoqing; Zeng, Donglin; Kosorok, Michael R.

    2015-01-01

    In this paper, we introduce a new type of tree-based method, reinforcement learning trees (RLT), which exhibits significantly improved performance over traditional methods such as random forests (Breiman, 2001) under high-dimensional settings. The innovations are three-fold. First, the new method implements reinforcement learning at each selection of a splitting variable during the tree construction processes. By splitting on the variable that brings the greatest future improvement in later splits, rather than choosing the one with largest marginal effect from the immediate split, the constructed tree utilizes the available samples in a more efficient way. Moreover, such an approach enables linear combination cuts at little extra computational cost. Second, we propose a variable muting procedure that progressively eliminates noise variables during the construction of each individual tree. The muting procedure also takes advantage of reinforcement learning and prevents noise variables from being considered in the search for splitting rules, so that towards terminal nodes, where the sample size is small, the splitting rules are still constructed from only strong variables. Last, we investigate asymptotic properties of the proposed method under basic assumptions and discuss rationale in general settings. PMID:26903687

  2. Fiber reinforced thermoplastic resin matrix composites

    NASA Technical Reports Server (NTRS)

    Jones, Robert J. (Inventor); Chang, Glenn E. C. (Inventor)

    1989-01-01

    Polyimide polymer composites having a combination of enhanced thermal and mechanical properties even when subjected to service temperatures as high as 700.degree. F. are described. They comprise (a) from 10 to 50 parts by weight of a thermoplastic polyimide resin prepared from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane and (b) from 90 to 50 parts by weight of continuous reinforcing fibers, the total of (a) and (b) being 100 parts by weight. Composites based on polyimide resin formed from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane and pyromellitic dianhydride and continuous carbon fibers retained at least about 50% of their room temperature shear strength after exposure to 700.degree. F. for a period of 16 hours in flowing air. Preferably, the thermoplastic polyimide resin is formed in situ in the composite material by thermal imidization of a corresponding amide-acid polymer prepared from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane. It is also preferred to initially size the continuous reinforcing fibers with up to about one percent by weight of an amide-acid polymer prepared from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane. In this way imidization at a suitable elevated temperature results in the in-situ formation of a substantially homogeneous thermoplastic matrix of the polyimide resin tightly and intimately bonded to the continuous fibers. The resultant composites tend to have optimum thermo-mechanical properties.

  3. Slender reinforced concrete columns strengthened with fibre reinforced polymers

    NASA Astrophysics Data System (ADS)

    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.

  4. How up- or downslope anchoring affects root reinforcement

    NASA Astrophysics Data System (ADS)

    Giadrossich, Filippo; Schwarz, Massimiliano; Cohen, Denis; Niedda, Marcello

    2016-04-01

    Root reinforcement is important for slope stability. In addition to the important contribution of roots to shear strength along the slip surface, root networks are also recognized to impart stabilization through lateral (parallel to slope) redistribution of forces under tension. The most common method to measure lateral root reinforcement is a pullout test where one root or a bundle of root is pulled out of the soil matrix. This condition represents the case where roots within the mass of a landslide slip out from the upper stable part of the slope. There is also, however, the situation where roots anchored in the upper stable part of the slope slip out from the sliding mass. In the latter it is difficult to quantify root reinforcement and no study has discussed this mechanism. We carried out a new series of laboratory and field experiments using Douglas fir (Pseudotsuga menziesii) roots to quantify how up- or downslope anchoring affects root reinforcement. In addition, we carried out new field pullout tests on coarse roots (larger that 2 mm in diameter, up to 47 mm). Then, considering the state-of-the-art of root reinforcement modeling (the Root Bundle Model), we integrated results from our measurements into the model to verify the magnitude of this effect on overall root reinforcement at the stand scale. Results indicate that the ratio between pullout force and force transferred to the root during soil slip ranges between 0.5 and 1. This indicates that measured pullout force always overestimate the contribution of lateral slipping out roots in situations where the soil slide from anchored roots. This is general the case for root with diameter up to 3-4 mm. Root-size distribution is also a key factor influencing root reinforcement at the forest-stand scale. As most coarse roots break along tension cracks while fine roots slip out, the effect discussed in this study on root reinforcement modeling is negligible when coarse-root diameter classes are represented. Our

  5. Analysis of stone-column reinforced foundations

    NASA Astrophysics Data System (ADS)

    Lee, J. S.; Pande, G. N.

    1998-12-01

    A numerical model is proposed to analyse elastic as well as elastoplastic behaviour of stone-column reinforced foundations. The stone-columns are assumed to be dispersed within the in situ soil and a homogenization technique is invoked to establish equivalent material properties for in situ soil and stone-column composite. The difficulties encountered in carrying out elastoplastic analyses of composite materials are overcome by adopting a separate yield function for each of the constituent materials and a sub-iteration procedure within an implicit backward Euler stress integration scheme. In the proposed procedure, equilibrium as well as kinematic conditions implied in the homogenization procedure are satisfied for both elastic as well as elastoplastic stress states.The proposed model is implemented in an axi-symmetric finite element code and numerical prediction is made for the behaviour of model circular footings resting on stone-column reinforced foundations. This prediction indicates good agreement with experimental observation. Finally, a new scheme in which the length of stone-column is variable is proposed and its behaviour is examined through a numerical example.

  6. Retaining clinician-scientists: nature versus nurture.

    PubMed

    Culican, Susan M; Rupp, Jason D; Margolis, Todd P

    2014-05-01

    career trajectory. To muffle the siren song of private practice and retain those best prepared for the clinician-scientist pathway requires additional investment as their careers mature through protected research time, mentorship, and advocacy. PMID:24867910

  7. Reinforcement in opinion dynamics

    NASA Astrophysics Data System (ADS)

    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.

  8. Fiber reinforced superalloys

    NASA Technical Reports Server (NTRS)

    Petrasek, Donald W.; Signorelli, Robert A.; Caulfield, Thomas; Tien, John K.

    1987-01-01

    Improved performance of heat engines is largely dependent upon maximum cycle temperatures. Tungsten fiber reinforced superalloys (TFRS) are the first of a family of high temperature composites that offer the potential for significantly raising hot component operating temperatures and thus leading to improved heat engine performance. This status review of TFRS research emphasizes the promising property data developed to date, the status of TFRS composite airfoil fabrication technology, and the areas requiring more attention to assure their applicability to hot section components of aircraft gas turbine engines.

  9. Temporal discrimination and delayed reinforcement.

    PubMed

    Buriticá, Jonathan; Vilchez, Zirahuén; Santos, Cristiano Valerio Dos

    2016-09-01

    We attempted to determine the effect of reinforcement delay on time discrimination in an interval bisection task. Three groups of rats were exposed to immediate, delayed reinforcement and longer signals with immediate reinforcement in acquisition and test. Results show differences in the amount of training necessary to reach the acquisition criteria, the Weber fraction and the range or overall stimulus control. The results suggest an increased difficulty to discriminate the difference among durations rather than an increase in estimated time as main effect of delayed reinforcement. PMID:27431922

  10. Hydraulic Properties of Unsaturated Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many agrophysical applications require knowledge of the hydraulic properties of unsaturated soils. These properties reflect the ability of a soil to retain or transmit water and its dissolved constituents. The objective of this work was to develop an entry for the Encyclopedia of Agrophysics that w...

  11. The impact of tropical forest logging and oil palm agriculture on the soil microbiome.

    PubMed

    Tripathi, Binu M; Edwards, David P; Mendes, Lucas William; Kim, Mincheol; Dong, Ke; Kim, Hyoki; Adams, Jonathan M

    2016-05-01

    Selective logging and forest conversion to oil palm agriculture are rapidly altering tropical forests. However, functional responses of the soil microbiome to these land-use changes are poorly understood. Using 16S rRNA gene and shotgun metagenomic sequencing, we compared composition and functional attributes of soil biota between unlogged, once-logged and twice-logged rainforest, and areas converted to oil palm plantations in Sabah, Borneo. Although there was no significant effect of logging history, we found a significant difference between the taxonomic and functional composition of both primary and logged forests and oil palm. Oil palm had greater abundances of genes associated with DNA, RNA, protein metabolism and other core metabolic functions, but conversely, lower abundance of genes associated with secondary metabolism and cell-cell interactions, indicating less importance of antagonism or mutualism in the more oligotrophic oil palm environment. Overall, these results show a striking difference in taxonomic composition and functional gene diversity of soil microorganisms between oil palm and forest, but no significant difference between primary forest and forest areas with differing logging history. This reinforces the view that logged forest retains most features and functions of the original soil community. However, networks based on strong correlations between taxonomy and functions showed that network complexity is unexpectedly increased due to both logging and oil palm agriculture, which suggests a pervasive effect of both land-use changes on the interaction of soil microbes. PMID:26994316

  12. Soil in the Anthropocene

    NASA Astrophysics Data System (ADS)

    Richter, Daniel deB; Bacon, Allan R.; Brecheisen, Zachary; Mobley, Megan L.

    2015-07-01

    With scholars deliberating a new name for our geologic epoch, i.e., the Anthropocene, soil scientists whether biologists, chemists, or physicists are documenting significant changes accruing in a majority of Earth's soils. Such global soil changes interact with the atmosphere, biosphere, hydrosphere, and lithosphere (i.e., Earth's Critical Zone), and these developments are significantly impacting the Earth's stratigraphic record as well. In effect, soil scientists study such global soil changes in a science of anthropedology, which leads directly to the need to transform pedostratigraphyinto an anthro-pedostratigraphy, a science that explores how global soil change alters Earth's litho-, bio-, and chemostratigraphy. These developments reinforce perspectives that the planet is indeed crossing into the Anthropocene.

  13. BEHAVIORAL MECHANISMS UNDERLYING NICOTINE REINFORCEMENT

    PubMed Central

    Rupprecht, Laura E.; Smith, Tracy T.; Schassburger, Rachel L.; Buffalari, Deanne M.; Sved, Alan F.; Donny, Eric C.

    2015-01-01

    Cigarette smoking is the leading cause of preventable deaths worldwide and nicotine, the primary psychoactive constituent in tobacco, drives sustained use. The behavioral actions of nicotine are complex and extend well beyond the actions of the drug as a primary reinforcer. Stimuli that are consistently paired with nicotine can, through associative learning, take on reinforcing properties as conditioned stimuli. These conditioned stimuli can then impact the rate and probability of behavior and even function as conditioning reinforcers that maintain behavior in the absence of nicotine. Nicotine can also act as a conditioned stimulus, predicting the delivery of other reinforcers, which may allow nicotine to acquire value as a conditioned reinforcer. These associative effects, establishing non-nicotine stimuli as conditioned stimuli with discriminative stimulus and conditioned reinforcing properties as well as establishing nicotine as a conditioned stimulus, are predicted by basic conditioning principles. However, nicotine can also act non-associatively. Nicotine directly enhances the reinforcing efficacy of other reinforcing stimuli in the environment, an effect that does not require a temporal or predictive relationship between nicotine and either the stimulus or the behavior. Hence, the reinforcing actions of nicotine stem both from the primary reinforcing actions of the drug (and the subsequent associative learning effects) as well as the reinforcement enhancement action of nicotine which is non-associative in nature. Gaining a better understanding of how nicotine impacts behavior will allow for maximally effective tobacco control efforts aimed at reducing the harm associated with tobacco use by reducing and/or treating its addictiveness. PMID:25638333

  14. Assessment of possibilities and conditions of irrigation in Hungary by digital soil map products

    NASA Astrophysics Data System (ADS)

    Laborczi, Annamária; Bakacsi, Zsófia; Takács, Katalin; Szatmári, Gábor; Szabó, József; Pásztor, László

    2016-04-01

    Sustaining proper soil moisture is essentially important in agricultural management. However, irrigation can be really worth only, if we lay sufficient emphasis on soil conservation. Nationwide planning of irrigation can be taken place, if we have spatially exhaustive maps and recommendations for the different areas. Soil moisture in the pores originate from 'above' (precipitation), or from 'beneath' (from groundwater by capillary lift). The level of groundwater depends on topography, climatic conditions and water regime of the nearby river. The thickness of capillary zone is basicly related to the physical and water management properties of the soil. Accordingly the capillary rise of sandy soils - with very high infiltration rate and very poor water retaining capacity - are far smaller than in the case of clay soils - with very poor infiltration rate and high water retaining capacity. Applying irrigation water can be considered as a reinforcement from 'above', and it affects the salinity and sodicity as well as the soil structure, nutrient supply and soil formation. We defined the possibilities of irrigation according to the average salt content of the soil profile. The nationwide mapping of soil salinity was based on legacy soil profile data, and it was carried out by regression kriging. This method allows that environmental factors with exhaustive spatial extension, such as climatic-, vegetation-, topographic-, soil- and geologic layers can be taken into consideration to the spatial extension of the reference data. According to soil salinity content categories, the areas were delineated as 1. to be irrigated, 2. to be irrigated conditionally, 3. not to be irrigated. The conditions of irrigation was determined by the comparison of the 'actual' and the 'critical' depth of the water table. Since, if the water rises above the critical level, undesirable processes, such as salinization and alkalinization can be developed. The critical depth of the water table was

  15. Reinforcing property of music in Java sparrows (Padda oryzivora).

    PubMed

    Watanabe, S; Nemoto, M

    1998-05-01

    The reinforcing property of music for Java sparrows was examined in a chamber with three perches. One of the end perches produced music by Bach while the other perch produced music by Schoenberg. Two of four birds significantly stayed longer on the perch associated with Bach music and retained their preference of Bach to Schoenberg when other pieces of music by Bach and Schoenberg were used. These two birds also preferred Vivaldi to Carter, suggesting preference for classical music over modern music. One of the two birds that did not show a preference between Bach and Schoenberg preferred Bach to a white noise, but the remaining one did not show any musical preference to noise. These results suggest that Java sparrows have musical preference and that the reinforcing properties depend on individuals. PMID:24896007

  16. Classroom Application of Structured Reinforcement.

    ERIC Educational Resources Information Center

    Bemis, Katherine A.; Schroeder, Glenn B.

    Results of pilot and field tests suggest that teachers should be encouraged to use the classroom management technique of structured reinforcement. In the 1967-68 pilot test 18 teachers (eight experimental and 10 control) systematically varied several parameters of reinforcement in classroom situations to determine their effects on the attainment…

  17. Stochastic Reinforcement Benefits Skill Acquisition

    ERIC Educational Resources Information Center

    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…

  18. Conditioned Reinforcement and Response Strength

    ERIC Educational Resources Information Center

    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…

  19. Delayed Reinforcement of Operant Behavior

    ERIC Educational Resources Information Center

    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…

  20. 40 CFR 98.257 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... In addition to the records required by § 98.3(g), you must retain the records of all parameters... under this subpart the records required for the Tier 3 and/or Tier 4 Calculation Methodologies in § 98... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained....

  1. 40 CFR 98.247 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... retained. In addition to the recordkeeping requirements in § 98.3(g), you must retain the records specified... Tier 4 Calculation Methodology in § 98.37, records of the procedures used to develop estimates of the... required under § 98.3(g)(5), record the estimated accuracy of measurement devices and the technical...

  2. 40 CFR 98.257 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Records that must be retained. 98.257 Section 98.257 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Petroleum Refineries § 98.257 Records that must be retained. In addition to the records required by...

  3. 40 CFR 98.257 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... In addition to the records required by § 98.3(g), you must retain the records of all parameters... under this subpart the records required for the Tier 3 and/or Tier 4 Calculation Methodologies in § 98... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained....

  4. 40 CFR 98.37 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Records that must be retained. 98.37 Section 98.37 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING General Stationary Fuel Combustion Sources § 98.37 Records that must be retained. In addition to...

  5. 40 CFR 98.257 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... In addition to the records required by § 98.3(g), you must retain the records of all parameters... under this subpart the records required for the Tier 3 and/or Tier 4 Calculation Methodologies in § 98... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained....

  6. 40 CFR 98.247 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Records that must be retained. 98.247 Section 98.247 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Petrochemical Production § 98.247 Records that must be retained. In addition to the...

  7. 40 CFR 98.247 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... retained. In addition to the recordkeeping requirements in § 98.3(g), you must retain the records specified... Tier 4 Calculation Methodology in § 98.37, records of the procedures used to develop estimates of the... required under § 98.3(g)(5), record the estimated accuracy of measurement devices and the technical...

  8. 49 CFR 240.215 - Retaining information supporting determinations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... permits reasonable access and retrieval of the information in usable format when requested to furnish data... 49 Transportation 4 2014-10-01 2014-10-01 false Retaining information supporting determinations... LOCOMOTIVE ENGINEERS Implementation of the Certification Process § 240.215 Retaining information...

  9. 49 CFR 242.203 - Retaining information supporting determinations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... storage permits reasonable access and retrieval of the information in usable format when requested to... 49 Transportation 4 2012-10-01 2012-10-01 false Retaining information supporting determinations... CONDUCTORS Administration of the Certification Program § 242.203 Retaining information...

  10. 49 CFR 240.215 - Retaining information supporting determinations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... permits reasonable access and retrieval of the information in usable format when requested to furnish data... 49 Transportation 4 2013-10-01 2013-10-01 false Retaining information supporting determinations... LOCOMOTIVE ENGINEERS Implementation of the Certification Process § 240.215 Retaining information...

  11. 49 CFR 240.215 - Retaining information supporting determinations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... permits reasonable access and retrieval of the information in usable format when requested to furnish data... 49 Transportation 4 2012-10-01 2012-10-01 false Retaining information supporting determinations... LOCOMOTIVE ENGINEERS Implementation of the Certification Process § 240.215 Retaining information...

  12. 40 CFR 98.427 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.427 Section 98.427 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.427 Records that must be retained. In addition to the records...

  13. 13 CFR 120.1707 - Seller's retained Loan Interest.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Seller's retained Loan Interest. 120.1707 Section 120.1707 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Establishment of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1707 Seller's retained Loan Interest. The...

  14. 49 CFR 240.215 - Retaining information supporting determinations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... permits reasonable access and retrieval of the information in usable format when requested to furnish data... 49 Transportation 4 2011-10-01 2011-10-01 false Retaining information supporting determinations... LOCOMOTIVE ENGINEERS Implementation of the Certification Process § 240.215 Retaining information...

  15. Oblique view of Bonita Ridge Access Road Retaining Wall, showing ...

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

    Oblique view of Bonita Ridge Access Road Retaining Wall, showing southernmost portion of intact wall and portion of concrete drainage ditch from Signal Corps Radar 296 Station 5 Transmitter Building foundation above, camera facing west-north - Fort Barry, Bonita Ridge Access Road, Retaining Wall, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

  16. Tools for Success in Recruiting and Retaining Hispanic Students

    ERIC Educational Resources Information Center

    Gilroy, Marilyn

    2010-01-01

    In this article, the author talks about strategies for success in recruiting and retaining Hispanic students. One strategy suggested by Raul Lorenzo, account director for Bauza & Associates, a Hispanic marketing agency that helps colleges and universities recruit and retain Hispanic students, is that institutions need to speak to the heart as well…

  17. 14 CFR 330.35 - What records must carriers retain?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., 2001, forecast was the most recent forecast available to that date. (3) You must also retain documentation outlining the assumptions made for all forecasts and the source of the data and other inputs used in making the forecasts. (4) You must agree to have your independent public accountant retain...

  18. 40 CFR 98.387 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.387 Records that... to the appropriate coal-to-liquid product supplier (e.g., retaining copies of all reports submitted... petroleum products that are required to be retained in § 98.397 are also required for...

  19. 40 CFR 98.387 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.387 Records that... to the appropriate coal-to-liquid product supplier (e.g., retaining copies of all reports submitted... petroleum products that are required to be retained in § 98.397 are also required for...

  20. 40 CFR 98.387 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.387 Records that... to the appropriate coal-to-liquid product supplier (e.g., retaining copies of all reports submitted... petroleum products that are required to be retained in § 98.397 are also required for...

  1. 40 CFR 98.387 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.387 Records that... to the appropriate coal-to-liquid product supplier (e.g., retaining copies of all reports submitted... petroleum products that are required to be retained in § 98.397 are also required for...

  2. 40 CFR 98.387 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.387 Records that... to the appropriate coal-to-liquid product supplier (e.g., retaining copies of all reports submitted... petroleum products that are required to be retained in § 98.397 are also required for...

  3. 40 CFR 98.437 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Contained in Pre-Charged Equipment or Closed-Cell Foams § 98.437 Records that must be retained. (a) In... closed-cell foams must retain the following records substantiating each of the imports that they report... entry form. (4) Ports of entry through which the pre-charged equipment or closed-cell foams passed....

  4. 40 CFR 98.437 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Contained in Pre-Charged Equipment or Closed-Cell Foams § 98.437 Records that must be retained. (a) In... closed-cell foams must retain the following records substantiating each of the imports that they report... entry form. (4) Ports of entry through which the pre-charged equipment or closed-cell foams passed....

  5. 5 CFR 536.306 - Limitation on retained rates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... other law or regulation to the rate of basic pay the employee would have received but for this... AND PAY RETENTION Pay Retention § 536.306 Limitation on retained rates. (a) A retained rate may not at any time exceed the rate payable for level IV of the Executive Schedule. (b) When an...

  6. Detail of basaltic rock retaining walls just below top switchback. ...

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

    Detail of basaltic rock retaining walls just below top switchback. 500 ft long retaining wall at left, scale figure in distance, view south. - La Bajada Historic Trails and Roads, Approximately 1 mile East/Northeast of intersection of State Highway 16 and Indian Service Road 841, La Bajada, Santa Fe County, NM

  7. Teacher Preferences for Various Positive Reinforcements.

    ERIC Educational Resources Information Center

    Derevensky, Jeffrey L.; Rose, Malcolm I.

    1978-01-01

    Investigated the relationship between applied behavioral training and reinforcement preferences of classroom teachers. Data obtained from the Positive Reinforcement Observation Schedule, a paired comparison task, indicated minimal differential reinforcement preferences for classroom teachers with no training, limited training, or extensive…

  8. Negative effects of positive reinforcement

    PubMed Central

    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 the distinction is untenable). When the distinction is made purely in operational terms, experiments reveal that positive reinforcement has aversive functions. On a practical level, positive reinforcement can lead to deleterious effects, and it is implicated in a range of personal and societal problems. These issues challenge us to identify other criteria for judging behavioral procedures. ImagesFigure 1Figure 2 PMID:22478391

  9. Thermally activated retainer means utilizing shape memory alloy

    NASA Technical Reports Server (NTRS)

    Grimaldi, Margaret E. (Inventor); Hartz, Leslie S. (Inventor)

    1993-01-01

    A retainer member suitable for retaining a gap filler placed in gaps between adjacent tile members is presented. One edge of the retainer member may be attached to the gap filler and another edge may be provided with a plurality of tab members which in an intermediate position do not interfere with placement or removal of the gap filler between tile members. The retainer member may be fabricated from a shape memory alloy which when heated to a specified memory temperature will thermally activate the tab members to predetermined memory positions engaging the tile members to retain the gap filler in the gap. This invention has particular application to the thermal tiles on space vehicles such as the Space Shuttle Orbiter.

  10. Structural Evolution of Silicon Oxynitride Fiber Reinforced Boron Nitride Matrix Composite at High Temperatures

    NASA Astrophysics Data System (ADS)

    Zou, Chunrong; Li, Bin; Zhang, Changrui; Wang, Siqing; Xie, Zhengfang; Shao, Changwei

    2016-02-01

    The structural evolution of a silicon oxynitride fiber reinforced boron nitride matrix (Si-N-Of/BN) wave-transparent composite at high temperatures was investigated. When heat treated at 1600 °C, the composite retained a favorable bending strength of 55.3 MPa while partially crystallizing to Si2N2O and h-BN from the as-received amorphous structure. The Si-N-O fibers still performed as effective reinforcements despite the presence of small pores due to fiber decomposition. Upon heat treatment at 1800 °C, the Si-N-O fibers already lost their reinforcing function and rough hollow microstructure formed within the fibers because of the accelerated decomposition. Further heating to 2000 °C led to the complete decomposition of the reinforcing fibers and only h-BN particles survived. The crystallization and decomposition behaviors of the composite at high temperatures are discussed.

  11. Whisker reinforced glass ceramic

    SciTech Connect

    Hirschfeld, D.A.; Brown, J.J. Jr.

    1996-06-03

    The process for making an in-situ whisker reinforced glass-ceramic that is up to 1.5 times as strong as conventional glass-ceramics was developed at Virginia Tech and patented in 1993. This technology has been identified as having commercial potential for use in high temperature heat exchanger applications for the electric power generation field by the National Center for Appropriate Technology (NCAT). This technology was licensed by MATVA, Inc., a small Virginia business, for further development. In particular, the goal of this project was to develop a property database and conduct initial testing of heat exchanger prototypes to demonstrate its potential application. This final report describes how the glass precursor was formed, physical properties of the glass-ceramic, techniques for making heat exchanger prototypes.

  12. Managing pine straw harvests to minimize soil and water losses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pine straw is a valuable landscape mulch because it conserves soil moisture, moderates soil temperature, inhibits weed growth, and protects the soil surface against erosion, while retaining a loose structure that allows water, air, and fertilizer to easily reach the soil surface. As a result, marke...

  13. Retained Urethral Catheter Secondary to Placement in Proximal Ureter

    PubMed Central

    Sharda, Rajan

    2016-01-01

    We present an unusual complication secondary to indwelling urethral catheter placement. Routine catheter placement by the obstetrics team in a postpartum female leads to retention of the catheter and inability of its removal by both the obstetrics and urology teams. Although a retained urinary catheter is relatively common, inability to remove a catheter secondary to placement inadvertently into a ureter is extremely rare. In this paper we will discuss the options in removing a retained catheter and present our case of a retained catheter secondary to placement within the right proximal ureter. PMID:27144050

  14. Micromechanics for particulate reinforced composites

    NASA Technical Reports Server (NTRS)

    Murthy, Pappu L. N.; Goldberg, Robert K.; Mital, Subodh K.

    1996-01-01

    A set of micromechanics equations for the analysis of particulate reinforced composites is developed using the mechanics of materials approach. Simplified equations are used to compute homogenized or equivalent thermal and mechanical properties of particulate reinforced composites in terms of the properties of the constituent materials. The microstress equations are also presented here to decompose the applied stresses on the overall composite to the microstresses in the constituent materials. The properties of a 'generic' particulate composite as well as those of a particle reinforced metal matrix composite are predicted and compared with other theories as well as some experimental data. The micromechanics predictions are in excellent agreement with the measured values.

  15. Fiber-reinforced syntactic foams

    NASA Astrophysics Data System (ADS)

    Huang, Yi-Jen

    Long fibers are generally preferred for reinforcing foams for performance reasons. However, uniform dispersion is difficult to achieve because they must be mixed with liquid resin prior to foam expansion. New approaches aiming to overcome such problem have been developed at USC's Composites Center. Fiber-reinforced syntactic foams with long fibers (over 6 mm in length) manufactured at USC's Composites Center have achieved promising mechanical properties and demonstrated lower density relative to conventional composite foams. Fiber-reinforced syntactic foams were synthesized from thermosetting polymeric microspheres (amino and phenolic microspheres), as well as thermoplastic PVC heat expandable microspheres (HEMs). Carbon and/or aramid fibers were used to reinforce the syntactic foams. Basic mechanical properties, including shear, tensile, and compression, were measured in syntactic foams and fiber-reinforced syntactic foams. Microstructure and crack propagation behavior were investigated by scanning electron microscope and light microscopy. Failure mechanisms and reinforcing mechanisms of fiber-reinforced syntactic foams were also analyzed. As expected, additions of fiber reinforcements to foams enhanced both tensile and shear properties. However, only limited enhancement in compression properties was observed, and fiber reinforcement was of limited benefit in this regard. Therefore, a hybrid foam design was explored and evaluated in an attempt to enhance compression properties. HEMs were blended with glass microspheres to produce hybrid foams, and hybrid foams were subsequently reinforced with continuous aramid fibers to produce fiber-reinforced hybrid foams. Mechanical properties of these foams were evaluated. Findings indicated that the production of hybrid foams was an effective way to enhance the compressive properties of syntactic foams, while the addition of fiber reinforcements enhanced the shear and tensile performance of syntactic foams. Another approach

  16. Sand reinforced with shredded waste tires

    SciTech Connect

    Foose, G.J.; Benson, C.H.; Bosscher, P.J.

    1996-09-01

    The objective of this study was to investigate the feasibility of using shredded waste tires to reinforce sand. Direct shear tests were conducted on mixtures of dry sand and shredded waste tires. The following factors were studied to evaluate their influence on shear strength: normal stress, sand matrix unit weight, shred content, shred length, and shred orientation. From results of the tests, three significant factors affecting shear strength were identified: normal stress, shred content, and sand matrix unit weight. A model for estimating the strength of reinforced soils was also evaluated to determine its applicability to mixtures of sand and tire shreds. When the model is calibrated using results from one shred content, it may be useful for estimating the friction angle for other shred contents. In all cases, adding shredded tires increased the shear strength of sand, with an apparent friction angle ({phi}{prime}) as large as 67{degree} being obtained. Shred content and sand matrix unit weight were the most significant characteristics of the mixes influencing shear strength. Increasing either of these variables resulted in an increase in {phi}{prime}. Tests were also conducted on specimens consisting of only shredded tires (no sand), and the friction angle obtained was 30{degree}.

  17. Function transformation without reinforcement.

    PubMed

    Tonneau, Franćois; Arreola, Fara; Martínez, Alma Gabriela

    2006-05-01

    In studies of function transformation, participants initially are taught to match stimuli in the presence of a contextual cue, X; the stimuli to be matched bear some formal relation to each other, for example, a relation of opposition or difference. In a second phase, the participants are taught to match arbitrary stimuli (say, A and B) in the presence of X. In a final test, A often displays behavioral functions that differ from those of B, and can be predicted from the nature of the relation associated with X in the initial training phase. Here we report function-transformation effects in the absence of selection responses and of their reinforcers. In three experiments with college students, exposure to relations of difference or identity modified the responses given to later stimuli. In Experiment 1, responses to a test stimulus A varied depending on preexposure to pairs of colors that were distinct from A but exemplified relations of difference or identity. In Experiment 2, a stimulus A acquired distinct functions, depending on its previous pairing with a contextual cue X that had itself been paired with identity or difference among colors. Experiment 3 confirmed the results of Experiment 2 with a modified design. Our data are consistent with the notion that relations of identity or difference can serve as stimuli for Pavlovian processes, and, in compound with other cues, produce apparent function-transformation effects. PMID:16776058

  18. Function Transformation without Reinforcement

    PubMed Central

    Tonneau, François; Arreola, Fara; Martínez, Alma Gabriela

    2006-01-01

    In studies of function transformation, participants initially are taught to match stimuli in the presence of a contextual cue, X; the stimuli to be matched bear some formal relation to each other, for example, a relation of opposition or difference. In a second phase, the participants are taught to match arbitrary stimuli (say, A and B) in the presence of X. In a final test, A often displays behavioral functions that differ from those of B, and can be predicted from the nature of the relation associated with X in the initial training phase. Here we report function-transformation effects in the absence of selection responses and of their reinforcers. In three experiments with college students, exposure to relations of difference or identity modified the responses given to later stimuli. In Experiment 1, responses to a test stimulus A varied depending on preexposure to pairs of colors that were distinct from A but exemplified relations of difference or identity. In Experiment 2, a stimulus A acquired distinct functions, depending on its previous pairing with a contextual cue X that had itself been paired with identity or difference among colors. Experiment 3 confirmed the results of Experiment 2 with a modified design. Our data are consistent with the notion that relations of identity or difference can serve as stimuli for Pavlovian processes, and, in compound with other cues, produce apparent function-transformation effects. PMID:16776058

  19. Ceramic fiber reinforced filter

    DOEpatents

    Stinton, David P.; McLaughlin, Jerry C.; Lowden, Richard A.

    1991-01-01

    A filter for removing particulate matter from high temperature flowing fluids, and in particular gases, that is reinforced with ceramic fibers. The filter has a ceramic base fiber material in the form of a fabric, felt, paper of the like, with the refractory fibers thereof coated with a thin layer of a protective and bonding refractory applied by chemical vapor deposition techniques. This coating causes each fiber to be physically joined to adjoining fibers so as to prevent movement of the fibers during use and to increase the strength and toughness of the composite filter. Further, the coating can be selected to minimize any reactions between the constituents of the fluids and the fibers. A description is given of the formation of a composite filter using a felt preform of commercial silicon carbide fibers together with the coating of these fibers with pure silicon carbide. Filter efficiency approaching 100% has been demonstrated with these filters. The fiber base material is alternately made from aluminosilicate fibers, zirconia fibers and alumina fibers. Coating with Al.sub.2 O.sub.3 is also described. Advanced configurations for the composite filter are suggested.

  20. 40 CFR 98.427 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of a facility containing production process units must retain quarterly records of captured or transferred CO2 streams and composition. (b) The owner or operator of a CO2 production well facility...

  1. 40 CFR 98.427 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... of a facility containing production process units must retain quarterly records of captured or transferred CO2 streams and composition. (b) The owner or operator of a CO2 production well facility...

  2. 40 CFR 98.427 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... of a facility containing production process units must retain quarterly records of captured or transferred CO2 streams and composition. (b) The owner or operator of a CO2 production well facility...

  3. 14. DETAIL OF TRANSITION FROM WING WALL TO CONCRETE RETAINING ...

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

    14. DETAIL OF TRANSITION FROM WING WALL TO CONCRETE RETAINING WALL AT SOUTHERN END OF DAM - Upper Doughty Dam, 200 feet west of Garden State Parkway, 1.7 miles west of Absecon, Egg Harbor City, Atlantic County, NJ

  4. 11. EAST VIEW OF RETAINING WALL C ON NORTH SIDE ...

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

    11. EAST VIEW OF RETAINING WALL C ON NORTH SIDE OF EASTBOUND TRAFFIC LANES, EAST OF HAMILTON AVENUE BRIDGE - Davison Freeway from M-10 to Oakland Avenue, Davison Freeway, M-10 to Highland Park, Highland Park, MI

  5. Virtual techniques for designing and fabricating a retainer.

    PubMed

    Nasef, Ahmed A; El-Beialy, Amr R; Mostafa, Yehya A

    2014-09-01

    The purpose of this article was to report a procedure for using 3-dimensional cone-beam computed tomography imaging, computer-aided design, computer-aided manufacturing, and rapid prototyping to design and produce a retainer. PMID:25172262

  6. 4. CONSTRUCTION DETAIL, SW CORNER, SHOWING RETAINING WALL, BRIDGE WALL ...

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

    4. CONSTRUCTION DETAIL, SW CORNER, SHOWING RETAINING WALL, BRIDGE WALL AND EROSION ON ROAD SURFACE. - Bridalveil Fall Bridge No. 3, Spanning Bridalveil Creek on carriage road, Yosemite Village, Mariposa County, CA

  7. Concrete and timber retaining wall and telegraph pole, milepost 145 ...

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

    Concrete and timber retaining wall and telegraph pole, milepost 145 vicinity, looking northeast. - Western Maryland Railway, Cumberland Extension, Pearre to North Branch, from WM milepost 125 to 160, Pearre, Washington County, MD

  8. Stone retaining wall with telegraph pole along canal, milepost 146 ...

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

    Stone retaining wall with telegraph pole along canal, milepost 146 vicinity, looking northeast. - Western Maryland Railway, Cumberland Extension, Pearre to North Branch, from WM milepost 125 to 160, Pearre, Washington County, MD

  9. 40 CFR 98.67 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.67 Records that must be retained. In... aluminum production in metric tons. (b) Type of smelter technology used. (c) The following...

  10. 40 CFR 98.67 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.67 Records that must be retained. In... aluminum production in metric tons. (b) Type of smelter technology used. (c) The following...

  11. 40 CFR 98.67 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.67 Records that must be retained. In... aluminum production in metric tons. (b) Type of smelter technology used. (c) The following...

  12. 40 CFR 98.67 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.67 Records that must be retained. In... aluminum production in metric tons. (b) Type of smelter technology used. (c) The following...

  13. 40 CFR 98.67 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.67 Records that must be retained. In... aluminum production in metric tons. (b) Type of smelter technology used. (c) The following...

  14. STONE RETAINING WALL IN CEMETERY CENTER, WITH BIVOUAC OF THE ...

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

    STONE RETAINING WALL IN CEMETERY CENTER, WITH BIVOUAC OF THE DEAD PLAQUE IN CENTER FOREGROUND. VIEW TO SOUTHEAST. - Fort Mackinac Post Cemetery, Mackinac State Park, Mackinac Island, Mackinac County, MI

  15. 40 CFR 98.167 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.167 Records that must be retained. In...) through (b) of this section for each hydrogen production facility. (a) If a CEMS is used to measure...

  16. 40 CFR 98.167 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.167 Records that must be retained. In...) through (b) of this section for each hydrogen production facility. (a) If a CEMS is used to measure...

  17. 40 CFR 98.167 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.167 Records that must be retained. In...) through (b) of this section for each hydrogen production facility. (a) If a CEMS is used to measure...

  18. 40 CFR 98.167 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.167 Records that must be retained. In...) through (b) of this section for each hydrogen production facility. (a) If a CEMS is used to measure...

  19. RIVER AND ROAD VIEW SHOWING METAL CRIB RETAINING WALLS AT ...

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

    RIVER AND ROAD VIEW SHOWING METAL CRIB RETAINING WALLS AT RIGHT, FACING SOUTHWEST. PHOTO IS TAKEN FROM SAME POSITION AS PHOTO NO. 84, BUT WITH LONG LENS - Generals Highway, Three Rivers, Tulare County, CA

  20. Mandibular Overdenture Retained by Magnetic Assembly: A Clinical tip.

    PubMed

    Anupam, Purwar; Anandakrishna, G N; Vibha, Shetty; Suma, Janya; Shally, Khanna

    2014-12-01

    The preservation of remaining root structure and alveolar bone covering them with denture has been used since many years. Tooth-retained overdentures transfer occlusal forces to the alveolar bone through the periodontal ligament of the retained tooth roots and thereby prevent bone resorption. Applications of magnets in overdenture technique has been widely used in dentistry in the field of prosthodontics, as they can be manufactured in small dimensions as retentive devices for complete denture, removable partial dentures, obturators and maxillofacial prosthesis. This article presents a simple and efficient method of fabrication of mandibular over denture retained by magnets in a patient whose mandibular residual ridge is severely resorbed with few remaining teeth and maxillary conventional removable partial denture. Mandibular over denture retained by magnets assembly consist of magnet and coping with keeper on remaining tooth structure to rehabilitate the patient since magnetic attachments can provide support, stability and retention. PMID:26199541

  1. 49 CFR 240.215 - Retaining information supporting determinations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... LOCOMOTIVE ENGINEERS Implementation of the Certification Process § 240.215 Retaining information supporting...) If a railroad relies on the use of a locomotive operations simulator to conduct the...

  2. 40 CFR 98.77 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.77 Records that must be retained... paragraphs (a) and (b) of this section for each ammonia manufacturing unit. (a) If a CEMS is used to...

  3. 40 CFR 98.77 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.77 Records that must be retained... paragraphs (a) and (b) of this section for each ammonia manufacturing unit. (a) If a CEMS is used to...

  4. 40 CFR 98.77 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.77 Records that must be retained... paragraphs (a) and (b) of this section for each ammonia manufacturing unit. (a) If a CEMS is used to...

  5. 40 CFR 98.77 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.77 Records that must be retained... paragraphs (a) and (b) of this section for each ammonia manufacturing unit. (a) If a CEMS is used to...

  6. 40 CFR 98.77 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.77 Records that must be retained... paragraphs (a) and (b) of this section for each ammonia manufacturing unit. (a) If a CEMS is used to...

  7. VIEW OF RETAINING WALL BEHIND FACILITY 532. VIEW FACING EAST ...

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

    VIEW OF RETAINING WALL BEHIND FACILITY 532. VIEW FACING EAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  8. 15. VIEW LOOKING EAST, SHOWING RETAINING WALL ON EAST SIDE ...

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

    15. VIEW LOOKING EAST, SHOWING RETAINING WALL ON EAST SIDE OF PARK, SOUTH OF ENGINE HOUSE (4' X 5' negative) - Fairmount Waterworks, East bank of Schuylkill River, Aquarium Drive, Philadelphia, Philadelphia County, PA

  9. 1. VIEW TO SOUTH (RETAINING WALL OF ORE RECEIVING PLATFORM ...

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

    1. VIEW TO SOUTH (RETAINING WALL OF ORE RECEIVING PLATFORM TO LEFT). - Vanadium Corporation of America (VCA) Naturita Mill, Sampling Building & Ore Receiving Platform, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

  10. 40 CFR 98.327 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Underground Coal Mines § 98.327 Records that must be retained... for calibration. (b) Records of gas sales. (c) Logbooks of parameter measurements. (d)...

  11. 40 CFR 98.327 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Underground Coal Mines § 98.327 Records that must be retained... for calibration. (b) Records of gas sales. (c) Logbooks of parameter measurements. (d)...

  12. 40 CFR 98.327 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Underground Coal Mines § 98.327 Records that must be retained... for calibration. (b) Records of gas sales. (c) Logbooks of parameter measurements. (d)...

  13. 40 CFR 98.327 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Underground Coal Mines § 98.327 Records that must be retained... for calibration. (b) Records of gas sales. (c) Logbooks of parameter measurements. (d)...

  14. 40 CFR 98.167 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.167 Records that must be retained. In...) through (b) of this section for each hydrogen production facility. (a) If a CEMS is used to measure...

  15. 24. VIEW TO NORTHEAST; OBLIQUE VIEW OF SOUTH RETAINING WALL ...

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

    24. VIEW TO NORTHEAST; OBLIQUE VIEW OF SOUTH RETAINING WALL AND PARKING STRUCTURE BELOW REA LOADING DOCK (Asano) - Los Angeles Union Passenger Terminal, Mail, Baggage, & Express Building, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  16. 6. TERRACED, STONE RETAINING WALLS BEHIND HOUSE No. 16. VIEW ...

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

    6. TERRACED, STONE RETAINING WALLS BEHIND HOUSE No. 16. VIEW TO WEST. - Rainbow Hydroelectric Facility, On north bank of Missouri River 2 miles Northeast of Great Falls, & end of Rainbow Dam Road, Great Falls, Cascade County, MT

  17. EDTA retention and emissions from remediated soil.

    PubMed

    Jez, Erika; Lestan, Domen

    2016-05-01

    EDTA-based remediation is reaching maturity but little information is available on the state of chelant in remediated soil. EDTA soil retention was examined after extracting 20 soil samples from Pb contaminated areas in Slovenia, Austria, Czech Republic and USA with 120 mM kg(-1) Na2H2EDTA, CaNa2EDTA and H4EDTA for 2 and 24 h. On average, 73% of Pb was removed from acidic and 71% from calcareous soils (24 h extractions). On average, 15% and up to 64% of applied EDTA was after remediation retained in acidic soils. Much less; in average 1% and up to the 22% of EDTA was retained in calcareous soils. The secondary emissions of EDTA retained in selected remediated soil increased with the acidity of the media: the TCLP (Toxicity Characteristic Leaching Procedure) solution (average pH end point 3.6) released up to 36% of EDTA applied in the soil (28.1 mmol kg(-1)). Extraction with deionised water (pH > 6.0) did not produce measurable EDTA emissions. Exposing soil to model abiotic (thawing/freezing cycles) and biotic (ingestion by earthworms Lumbricus rubellus) ageing factors did not induce additional secondary emissions of EDTA retained in remediated soil. PMID:26943741

  18. Response deprivation, reinforcement, and economics

    PubMed Central

    Allison, James

    1993-01-01

    Reinforcement of an instrumental response results not from a special kind of response consequence known as a reinforcer, but from a special kind of schedule known as a response-deprivation schedule. Under the requirements of a response-deprivation schedule, the baseline rate of the instrumental response permits less than the baseline rate of the contingent response. Because reinforcement occurs only if the schedule deprives the organism of the contingent response, reinforcement cannot result from any intrinsic property of the contingent response or any property relative to the instrumental response. Two typical effects of response-deprivation schedules—facilitation of the instrumental response and suppression of the contingent response—are discussed in terms of economic concepts and models of instrumental performance. It is suggested that response deprivation makes the contingent response function as an economic good, the instrumental response as currency. PMID:16812695

  19. Reinforcing Behavior of "Naive" Trainers

    ERIC Educational Resources Information Center

    Lanzetta, John T.; Hannah, T. E.

    1969-01-01

    Presents an experiment showing that naive trainers tend to allow factors such as task difficulty and competence of the trainee to affect the kind of reinforcement administered. Bibliography, tables, and graphs. (JB)

  20. Clinical pearl: LingLock--the flossable fixed retainer.

    PubMed

    Amundsen, O C; Wisth, P J

    2005-12-01

    The present article describes a new product for long-term retention of the lower dental arch. The LingLock is a fixed bonded retainer from canine to canine in the lower front made up of separate, but co-working retention elements in the ceramic material aluminium oxide (Al2O3). The LingLock retainer enables the patient to floss the teeth in a regular manner in the actual retention area. PMID:16333044

  1. 21 CFR 178.3850 - Reinforced wax.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Reinforced wax. 178.3850 Section 178.3850 Food and... Reinforced wax. Reinforced wax may be safely used as an article or component of articles intended for use in... this section. (a) Reinforced wax consists of petroleum wax to which have been added certain...

  2. 21 CFR 178.3850 - Reinforced wax.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Reinforced wax. 178.3850 Section 178.3850 Food and... and Production Aids § 178.3850 Reinforced wax. Reinforced wax may be safely used as an article or... holding food subject to the provisions of this section. (a) Reinforced wax consists of petroleum wax...

  3. 21 CFR 178.3850 - Reinforced wax.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Reinforced wax. 178.3850 Section 178.3850 Food and... and Production Aids § 178.3850 Reinforced wax. Reinforced wax may be safely used as an article or... holding food subject to the provisions of this section. (a) Reinforced wax consists of petroleum wax...

  4. 21 CFR 178.3850 - Reinforced wax.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Reinforced wax. 178.3850 Section 178.3850 Food and... and Production Aids § 178.3850 Reinforced wax. Reinforced wax may be safely used as an article or... holding food subject to the provisions of this section. (a) Reinforced wax consists of petroleum wax...

  5. 21 CFR 178.3850 - Reinforced wax.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Reinforced wax. 178.3850 Section 178.3850 Food and... and Production Aids § 178.3850 Reinforced wax. Reinforced wax may be safely used as an article or... holding food subject to the provisions of this section. (a) Reinforced wax consists of petroleum wax...

  6. Matching and Conditioned Reinforcement Rate

    PubMed Central

    Shahan, Timothy A; Podlesnik, Christopher A; Jimenez-Gomez, Corina

    2006-01-01

    Attempts to examine the effects of variations in relative conditioned reinforcement rate on choice have been confounded by changes in rates of primary reinforcement or changes in the value of the conditioned reinforcer. To avoid these problems, this experiment used concurrent observing responses to examine sensitivity of choice to relative conditioned reinforcement rate. In the absence of observing responses, unsignaled periods of food delivery on a variable-interval 90-s schedule alternated with extinction on a center key (i.e., a mixed schedule was in effect). Two concurrently available observing responses produced 15-s access to a stimulus differentially associated with the schedule of food delivery (S+). The relative rate of S+ deliveries arranged by independent variable-interval schedules for the two observing responses varied across conditions. The relation between the ratio of observing responses and the ratio of S+ deliveries was well described by the generalized matching law, despite the absence of changes in the rate of food delivery. In addition, the value of the S+ deliveries likely remained constant across conditions because the ratio of S+ to mixed schedule food deliveries remained constant. Assuming that S+ deliveries serve as conditioned reinforcers, these findings are consistent with the functional similarity between primary and conditioned reinforcers suggested by general choice theories based on the concatenated matching law (e.g., contextual choice and hyperbolic value-added models). These findings are inconsistent with delay reduction theory, which has no terms for the effects of rate of conditioned reinforcement in the absence of changes in rate of primary reinforcement. PMID:16673824

  7. Reinforced ceramics employing discontinuous phases

    SciTech Connect

    Becher, P.F.

    1990-01-01

    The fracture toughness of ceramics can be improved by the incorporation of a variety of discontinuous reinforcing phases and microstructures. Observations of crack paths in these systems indicate that these reinforcing phases bridge the crack tip wake region. Recent developments in micromechanics toughening models applicable to such systems are discussed and compared with experimental observations. Because material parameters and microstructural characteristics are considered, the crack bridging models provide a means to optimize the toughening effects. 18 refs., 2 figs.

  8. Carbon Nanotubes Reinforced Composites for Biomedical Applications

    PubMed Central

    Wang, Wei; Zhu, Yuhe; Liao, Susan; Li, Jiajia

    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 matrix composites, and CNTs reinforced ceramic matrix composites), their mechanical properties, cell experiments in vitro, and biocompatibility tests in vivo. PMID:24707488

  9. Methods for producing reinforced carbon nanotubes

    DOEpatents

    Ren, Zhifen; Wen, Jian Guo; Lao, Jing Y.; Li, Wenzhi

    2008-10-28

    Methods for producing reinforced carbon nanotubes having a plurality of microparticulate carbide or oxide materials formed substantially on the surface of such reinforced carbon nanotubes composite materials are disclosed. In particular, the present invention provides reinforced carbon nanotubes (CNTs) having a plurality of boron carbide nanolumps formed substantially on a surface of the reinforced CNTs that provide a reinforcing effect on CNTs, enabling their use as effective reinforcing fillers for matrix materials to give high-strength composites. The present invention also provides methods for producing such carbide reinforced CNTs.

  10. Evaluation of residual strength in the basalt fiber reinforced composites under impact damage

    NASA Astrophysics Data System (ADS)

    Kim, Yun-Hae; Lee, Jin-Woo; Moon, Kyung-Man; Yoon, Sung-Won; Baek, Tae-Sil; Hwang, Kwang-Il

    2015-03-01

    Composites are vulnerable to the impact damage by the collision as to the thickness direction, because composites are being manufactured by laminating the fiber. The understanding about the retained strength after the impact damage of the material is essential in order to secure the reliability of the structure design using the composites. In this paper, we have tried to evaluate the motion of the material according to the kinetic energy and potential energy and the retained strength after impact damage by testing the free fall test of the basalt fiber reinforced composite in the limelight as the environment friendly characteristic.

  11. Reproductive outcomes of retransferring retained embryos in blastocyst transfer cycles

    PubMed Central

    Yi, Hyun Jeong; Koo, Hwa Seon; Cha, Sun Hwa; Kim, Hye Ok; Park, Chan Woo

    2016-01-01

    Objective To determine the incidence of embryo retention (ER) in the transfer catheter following embryo transfer (ET) in blastocyst transfer and investigate whether retransferring retained embryos has an impact on reproductive outcomes in patients undergoing in vitro fertilization-ET. Methods We retrospectively analyzed the records of 1,131 blastocyst transfers, which comprised 223 single blastocyst transfer (SBT) and 908 double blastocyst transfer (DBT) cycles. Each SBT and DBT group was classified depending on whether ET was performed without retained embryos in the catheter during the first attempt (without-ER group) or whether any retained embryos were found following ET (ER group) for the purpose of comparing reproductive outcomes in a homogenous population. Results The overall incidence of finding retained embryos was 2.8% (32/1,131). There were no retained embryos in SBT cycles. In DBT cycles, implantation rates (30.0% vs. 26.6%), positive β-hCG rates (57.2% vs. 56.2%), clinical pregnancy rates (45.3% vs. 46.9%), and live birth rates (38.9% vs. 43.8%) were not significantly different between the without-ER and ER groups. There were no significant differences in the mean birth weight (g) 2,928.4±631.8 vs. 2,948.7±497.8 and the mean gestational age at birth (269.3±17.2 days vs. 264.2±25.7 days). A total of nine cases of congenital birth defects were found in this study population. Eight were observed in the without-ER group and one in the ER group. Conclusion Our results suggest that retransfer of retained embryos does not have any adverse impact on reproductive outcomes in blastocyst transfer cycles. Furthermore, our results support finding that SBT might be advantageous for decreasing the incidence of retained embryos in catheters. PMID:27358833

  12. Effect of Reinforcement Architecture on Fracture of Selectively Reinforced Metallic Compact Tension Specimens

    NASA Technical Reports Server (NTRS)

    Abada, Christopher H.; Farley, Gary L.; Hyer, Michael W.

    2006-01-01

    A computer-based parametric study of the effect of reinforcement architectures on fracture response of aluminum compact-tension (CT) specimens is performed. Eleven different reinforcement architectures consisting of rectangular and triangular cross-section reinforcements were evaluated. Reinforced specimens produced between 13 and 28 percent higher fracture load than achieved with the non-reinforced case. Reinforcements with blunt leading edges (rectangular reinforcements) exhibited superior performance relative to the triangular reinforcements with sharp leading edges. Relative to the rectangular reinforcements, the most important architectural feature was reinforcement thickness. At failure, the reinforcements carried between 58 and 85 percent of the load applied to the specimen, suggesting that there is considerable load transfer between the base material and the reinforcement.

  13. The Serum Lead level in Patients With Retained Lead Pellets

    PubMed Central

    Moazeni, Mohammad; Mohammad Alibeigi, Faramarz; Sayadi, Masoud; Poorya Mofrad, Ebrahim; Kheiri, Soleiman; Darvishi, Malihe

    2014-01-01

    Background: Patients, who survived from shotgun injuries, often have some retained lead pellets in their bodies. Several cases of lead toxicity have been reported regarding these patients. Objectives: This study seeks to compare the serum lead level in patients who have retained lead pellets in their bodies with the control group. Patients and Methods: In this case-control study, we gathered the serum lead levels of 25 patients with some retained lead pellets in their bodies due to shotgun and 25 volunteers without similar lead exposure and compared them in view of the age, gender, and living place. Results: While the mean serum lead level in both groups was lower than the standard level (i.e. 40 µg/dL) , the mean ± SD of serum lead level were 29 ± 12.8 µg/dL and 25.3 ± 6.4 µg/dL in the case and control groups, respectively without any significant difference (P = 0. 30) . However, a positive relationship was seen between serum lead level, and the number of retained lead pellets (r = 0.447, P = 0. 025) . Conclusions: Although extensive surgery to remove the lead pellets is not recommended in patients injured with shotguns, those with many retained lead pellets in their bodies should be considered at risk for lead poisoning and monitored carefully. PMID:25147780

  14. Seismic analysis for translational failure of landfills with retaining walls.

    PubMed

    Feng, Shi-Jin; Gao, Li-Ya

    2010-11-01

    In the seismic impact zone, seismic force can be a major triggering mechanism for translational failures of landfills. The scope of this paper is to develop a three-part wedge method for seismic analysis of translational failures of landfills with retaining walls. The approximate solution of the factor of safety can be calculated. Unlike previous conventional limit equilibrium methods, the new method is capable of revealing the effects of both the solid waste shear strength and the retaining wall on the translational failures of landfills during earthquake. Parameter studies of the developed method show that the factor of safety decreases with the increase of the seismic coefficient, while it increases quickly with the increase of the minimum friction angle beneath waste mass for various horizontal seismic coefficients. Increasing the minimum friction angle beneath the waste mass appears to be more effective than any other parameters for increasing the factor of safety under the considered condition. Thus, selecting liner materials with higher friction angle will considerably reduce the potential for translational failures of landfills during earthquake. The factor of safety gradually increases with the increase of the height of retaining wall for various horizontal seismic coefficients. A higher retaining wall is beneficial to the seismic stability of the landfill. Simply ignoring the retaining wall will lead to serious underestimation of the factor of safety. Besides, the approximate solution of the yield acceleration coefficient of the landfill is also presented based on the calculated method. PMID:20541389

  15. Implant-retained auricular prostheses: a clinical challenge.

    PubMed

    Arora, V; Sahoo, N K; Gopi, A; Saini, D K

    2016-05-01

    Microtia, malformation, deformity, and partial or complete loss of the pinna may be due to various congenital or acquired factors. In adult patients, surgical reconstruction of the missing pinna is difficult and the results are often far from satisfactory. An implant-retained auricular prosthesis is a suitable alternative. A retrospective study of eight patients treated with implant-retained auricular prostheses was performed. For each missing pinna, three titanium implants were placed in the temporal bone. After 6 months of osseointegration, the implants were loaded. Four cases were rehabilitated with a magnet-retained prosthesis and the remaining four with a bar and clip retained prosthesis. There were six male and two female patients with an average age of 30.62 years. Seven patients had unilateral absence of the pinna and one had bilateral absence. The loss was due to trauma in four patients and to burn in one patient, and three had congenital absence. A total 27 implants were placed, 12 on the right side and 15 on the left. The average post-rehabilitation follow-up was 21 months. Peri-implant tissue reactions were observed at two sites. The implant-retained auricular prosthesis is an alternative treatment approach with good retention and patient satisfaction. Long-term follow-up is required to assess delayed complications. PMID:26792146

  16. Replacement of a tooth with a fiber-reinforced direct bonded restoration.

    PubMed

    Shuman, I E

    2000-01-01

    Today's methods and materials for tooth replacement are multiple and varied. Modern materials now allow for highly conservative abutment preparations that can retain bonded single tooth replacement fixed prostheses. A case report is presented in which fiber reinforced with composite resin was used for placement of a three-unit fixed long-term provisional restoration, providing fracture resistance while achieving an esthetically pleasing, durable restoration. PMID:11199598

  17. Late corneal edema due to retained foldable lens fragment.

    PubMed

    Gokhale, Nikhil S

    2009-01-01

    Late onset of corneal edema after cataract surgery is an unusual complication. We report a case of corneal edema presenting one month after cataract surgery. During implantation of the foldable lens, one haptic of the intraocular lens fractured at the optic haptic junction. This caused lens decentration, necessitating an intraocular lens exchange ten days later. The patient was recovering well but presented again two weeks later with a drop in vision due to corneal edema. A retained haptic of the intraocular lens was seen in the inferior anterior chamber angle. After surgical removal of the retained haptic the corneal edema fully resolved. Retained intraocular lens fragments can cause corneal endothelial damage, which may be reversible with an early diagnosis and intervention. PMID:19384021

  18. Follicular Dendritic Cells Retain Infectious HIV in Cycling Endosomes

    PubMed Central

    Heesters, Balthasar A.; Lindqvist, Madelene; Vagefi, Parsia A.; Scully, Eileen P.; Schildberg, Frank A.; Altfeld, Marcus; Walker, Bruce D.; Kaufmann, Daniel E.; Carroll, Michael C.

    2015-01-01

    Despite the success of antiretroviral therapy (ART), it does not cure Human Immunodeficiency Virus (HIV) and discontinuation results in viral rebound. Follicular dendritic cells (FDC) are in direct contact with CD4+ T cells and they retain intact antigen for prolonged periods. We found that human FDC isolated from patients on ART retain infectious HIV within a non-degradative cycling compartment and transmit infectious virus to uninfected CD4 T cells in vitro. Importantly, treatment of the HIV+ FDC with a soluble complement receptor 2 purges the FDC of HIV virions and prevents viral transmission in vitro. Our results provide an explanation for how FDC can retain infectious HIV for extended periods and suggest a therapeutic strategy to achieve cure in HIV-infected humans. PMID:26623655

  19. Lead poisoning from retained bullets. Pathogenesis, diagnosis, and management.

    PubMed Central

    Linden, M A; Manton, W I; Stewart, R M; Thal, E R; Feit, H

    1982-01-01

    Lead intoxication (plumbism) from retained bullets has rarely been reported but may be fatal if unrecognized. Bullets lodged within joint spaces or pseudocysts are more likely to develop this complication, although patients with retained missiles in other locations may also be at risk. Subtle findings such as the occurrence of unexplained anemia, abdominal colic, nephropathy, or neurologic deterioration in patients with retained missiles may suggest consideration of plumbism. An intercurrent metabolic stress such as infection, endocrinopathy, or alcoholism may be a precipitating factor. Among the various diagnostic studies available, mass spectrometric stable isotope dilution analysis may be the most reliable. It is important to employ chelation therapy prior to any operative intervention. This will reduce the mobilization of lead from bone during or following the surgical procedure. Images Fig. 1. Fig. 3. Fig. 5. PMID:6800314

  20. Hybrid Approach to Reinforcement Learning

    NASA Astrophysics Data System (ADS)

    Boulebtateche, Brahim; Fezari, Mourad; Boughazi, Mohamed

    2008-06-01

    Reinforcement Learning (RL) is a general framework in which an autonomous agent tries to learn an optimal policy of actions from direct interaction with the surrounding environment (RL). However, one difficulty for the application of RL control is its slow convergence, especially in environments with continuous state space. In this paper, a modified structure of RL is proposed to speed up reinforcement learning control. In this approach, supervision technique is combined with the standard Q-learning, a model-free algorithm of reinforcement learning. The a priori information is provided to the RL by an optimal LQ-controller, used to indicate preferred actions at intermittent times. It is shown that the convergence speed of the supervised RL agent is greatly improved compared to the conventional Q-Learning algorithm. Simulation work and results on the cart-pole balancing problem are given to illustrate the efficiency of the proposed method.

  1. Bioinspired air-retaining nanofur for drag reduction.

    PubMed

    Kavalenka, Maryna N; Vüllers, Felix; Lischker, Simone; Zeiger, Claudia; Hopf, Andreas; Röhrig, Michael; Rapp, Bastian E; Worgull, Matthias; Hölscher, Hendrik

    2015-05-27

    Bioinspired nanofur, covered by a dense layer of randomly distributed high aspect ratio nano- and microhairs, possesses superhydrophobic and air-retaining properties. Nanofur is fabricated using a highly scalable hot pulling method in which softened polymer is elongated with a heated sandblasted plate. Here we investigate the stability of the underwater air layer retained by the irregular nanofur topography by applying hydraulic pressure to the nanofur kept underwater, and evaluate the gradual changes in the air-covered area. Furthermore, the drag reduction resulting from the nanofur air retention is characterized by measuring the pressure drop across channels with and without nanofur. PMID:25945543

  2. Reversible Corneal Toxicity of Retained Intracameral Perfluoro-n-octane

    PubMed Central

    Alharbi, Saad S.; Asiri, Mohammed S.

    2016-01-01

    A 58-year-old female presented with intracameral retained perfluoro-n-octane (PFO) following previous retinal reattachment surgery. After 4 years of follow-up without related sequelae, the patient complained of a gradual decrease in vision secondary to corneal edema with whitish corneal precipitate inferiorly corresponding to the area of retained PFO. Three weeks after anterior chamber washout, corneal edema resolved and the patient obtained 20/40 visual acuity. Even though PFO considered to have a relatively good safety profile, early anterior chamber washout may prevent corneal toxicity and avoid later persistent corneal decompensation. PMID:27555718

  3. Root canal retained restorations: 3. Root-face attachments.

    PubMed

    Dummer, P M; Edmunds, D H; Gidden, J R

    1990-10-01

    It has been common practice for many years to use retained roots to provide support and stability for partial or full dentures. The retention of such overdentures is greatly enhanced if the remaining roots are modified and restored with posts and root-face attachments. The final article in this series on root canal retained restorations classifies and describes some of the root-face attachments currently available, and also describes a number of prefabricated post systems with integral overdenture attachments. Guidelines for clinical and laboratory procedures are given. PMID:2097234

  4. Policy for prevention of a retained sponge after vaginal delivery.

    PubMed

    Garry, David J; Asanjarani, Sandra; Geiss, Donna M

    2012-01-01

    Background. Policies for sponge count are not routine practice in most labor and delivery rooms. Ignored or hidden retained vaginal foreign bodies has potentially significant health care morbidity. Case. This was a case of a retained vaginal sponge following an uncomplicated spontaneous vaginal delivery. Delivery room policy resulted in the discovery of the sponge on X-ray when an incorrect sponge count occurred and physical exam did not find the sponge. Conclusion. This emphasizes the use of protocols to enhance patient safety and prevent medical error. PMID:22312370

  5. Policy for Prevention of a Retained Sponge after Vaginal Delivery

    PubMed Central

    Garry, David J.; Asanjarani, Sandra; Geiss, Donna M.

    2012-01-01

    Background. Policies for sponge count are not routine practice in most labor and delivery rooms. Ignored or hidden retained vaginal foreign bodies has potentially significant health care morbidity. Case. This was a case of a retained vaginal sponge following an uncomplicated spontaneous vaginal delivery. Delivery room policy resulted in the discovery of the sponge on X-ray when an incorrect sponge count occurred and physical exam did not find the sponge. Conclusion. This emphasizes the use of protocols to enhance patient safety and prevent medical error. PMID:22312370

  6. Reversible Corneal Toxicity of Retained Intracameral Perfluoro-n-octane.

    PubMed

    Alharbi, Saad S; Asiri, Mohammed S

    2016-01-01

    A 58-year-old female presented with intracameral retained perfluoro-n-octane (PFO) following previous retinal reattachment surgery. After 4 years of follow-up without related sequelae, the patient complained of a gradual decrease in vision secondary to corneal edema with whitish corneal precipitate inferiorly corresponding to the area of retained PFO. Three weeks after anterior chamber washout, corneal edema resolved and the patient obtained 20/40 visual acuity. Even though PFO considered to have a relatively good safety profile, early anterior chamber washout may prevent corneal toxicity and avoid later persistent corneal decompensation. PMID:27555718

  7. Microwave NDE for Reinforced Concrete

    NASA Astrophysics Data System (ADS)

    Arunachalam, Kavitha; Melapudi, Vikram R.; Rothwell, Edward J.; Udpa, Lalita; Udpa, Satish S.

    2006-03-01

    Nondestructive assessment of the integrity of civil structures is of paramount importance for ensuring safety. In concrete imaging, radiography, ground penetrating radar and infrared thermography are some of the widely used techniques for health monitoring. Other emerging technologies that are gaining impetus for detecting and locating flaws in steel reinforcement bar include radioactive computed tomography, microwave holography, microwave and acoustic tomography. Of all the emerging techniques, microwave NDT is a promising imaging modality largely due to their ability to penetrate thick concrete structures, contrast between steel rebar and concrete and their non-radioactive nature. This paper investigates the feasibility of a far field microwave NDE technique for reinforced concrete structures.

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

    ERIC Educational Resources Information Center

    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…

  9. 40 CFR 98.37 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Records that must be retained. 98.37 Section 98.37 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING General Stationary Fuel Combustion Sources § 98.37...

  10. 40 CFR 98.37 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained. 98.37 Section 98.37 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING General Stationary Fuel Combustion Sources § 98.37...

  11. 40 CFR 98.187 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... in § 98.37 and the information specified in paragraphs (a)(1) through (a)(3) of this section. (1... addition to the records required by § 98.3(g), each annual report must contain the information specified in... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Records that must be retained....

  12. 40 CFR 98.37 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.37 Section 98.37 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING General Stationary Fuel Combustion Sources § 98.37...

  13. 40 CFR 98.187 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... in § 98.37 and the information specified in paragraphs (a)(1) through (a)(3) of this section. (1... addition to the records required by § 98.3(g), each annual report must contain the information specified in... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained....

  14. 40 CFR 98.187 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... in § 98.37 and the information specified in paragraphs (a)(1) through (a)(3) of this section. (1... addition to the records required by § 98.3(g), each annual report must contain the information specified in... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained....

  15. 40 CFR 98.37 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.37 Section 98.37 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING General Stationary Fuel Combustion Sources § 98.37...

  16. Colleges Try New Tactics to Retain Fund Raisers

    ERIC Educational Resources Information Center

    Strout, Erin

    2007-01-01

    A survey last year by the consulting firm Eduventures Inc. asked development officers at 72 public and private research institutions what their primary challenge was: 86 percent said recruiting, training, and retaining staff members. According to the Council for Advancement and Support of Education (CASE), 32 percent of fund raisers stay in their…

  17. Rural Education: Attracting and Retaining Teachers in Small Schools

    ERIC Educational Resources Information Center

    Lowe, Jerry M.

    2006-01-01

    For many small rural school districts across America, the effort to attract and retain quality teachers continues to be a major concern. Schools located in what are considered to be "hard to staff" areas experience the most difficult. While not all communities face the problems of inadequate teacher supply, many small and rural school districts…

  18. 40 CFR 98.147 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Glass Production § 98.147 Records that must be retained. In... paragraphs (a)(1) and (a)(2) of this section: (1) Monthly glass production rate for each continuous glass... glass melting furnace (tons). (b) If process CO2 emissions are calculated according to the...

  19. 40 CFR 98.147 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Glass Production § 98.147 Records that must be retained. In... paragraphs (a)(1) and (a)(2) of this section: (1) Monthly glass production rate for each continuous glass... glass melting furnace (tons). (b) If process CO2 emissions are calculated according to the...

  20. 40 CFR 98.147 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Glass Production § 98.147 Records that must be retained. In... paragraphs (a)(1) and (a)(2) of this section: (1) Monthly glass production rate for each continuous glass... glass melting furnace (tons). (b) If process CO2 emissions are calculated according to the...

  1. View looking SW at brick retaining wall running parallel to ...

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

    View looking SW at brick retaining wall running parallel to Jones Street showing bricked up storage vaults - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Brick Storage Vaults under Jones Street, Bounded by West Broad, Jones, West Boundary & Hull Streets, Savannah, Chatham County, GA

  2. Good Laboratory Practice. Part 2. Recording and Retaining Raw Data

    ERIC Educational Resources Information Center

    Wedlich, Richard C.; Libera, Agata E.; Pires, Amanda; Tellarini, Cassandra

    2013-01-01

    A clear understanding of how "raw data" is defined, recorded, and retained in the laboratory record is essential to the chemist employed in the laboratory compliant with the Good Laboratory Practices regulations. This article is intended to provide an understanding by drawing upon examples taken from the modern pharmaceutical analysis…

  3. Retaining Urban Middle School Teachers: An Investigation of Influencing Factors

    ERIC Educational Resources Information Center

    Richardson, JacQueline Elaine

    2012-01-01

    President William Jefferson Clinton is often credited with beginning a new era of improving teacher quality. Since the late 1990's, the federal government has presented a number of reforms that have encouraged states to develop methods to address the revolving door of teachers entering and exiting schools yearly. Retaining teachers has been…

  4. 40 CFR 98.227 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Records that must be retained. 98.227 Section 98.227 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... technology destruction efficiency (if applicable). (c) Performance test reports. (d) Number of...

  5. 40 CFR 98.417 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained. 98.417 Section 98.417 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.417 Records...

  6. 40 CFR 98.57 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Records that must be retained. 98.57 Section 98.57 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.57 Records that must be...

  7. 40 CFR 98.57 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.57 Section 98.57 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.57 Records that must be...

  8. 40 CFR 98.437 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained. 98.437 Section 98.437 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Importers and Exporters of Fluorinated Greenhouse...

  9. 40 CFR 98.437 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.437 Section 98.437 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Importers and Exporters of Fluorinated Greenhouse...

  10. 40 CFR 98.417 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Records that must be retained. 98.417 Section 98.417 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.417 Records...

  11. 40 CFR 98.417 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Records that must be retained. 98.417 Section 98.417 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.417 Records...

  12. 40 CFR 98.417 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.417 Section 98.417 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.417 Records...

  13. 40 CFR 98.117 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Records that must be retained. 98.117 Section 98.117 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ferroalloy Production § 98.117 Records that must be...

  14. 40 CFR 98.57 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.57 Section 98.57 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.57 Records that must be...

  15. 40 CFR 98.417 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.417 Section 98.417 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.417 Records...

  16. An Integrated Approach to Recruiting and Retaining Appalachian Engineering Students

    ERIC Educational Resources Information Center

    Winn, Gary; Hensel, Robin; Curtis, Reagan; Taylor, Lydotta M.; Cilento, Gene

    2012-01-01

    Recruiting and retaining Appalachian engineering students is difficult for a variety of ecological and cultural reasons. At West Virginia University an NSF STEP grant has allowed the development of specific interventions to evolve from an ecological model we describe here. The interventions include web-based, realistic engineering design exercises…

  17. 40 CFR 98.47 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Records that must be retained. 98.47 Section 98.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.47 Records that must be...

  18. 40 CFR 98.47 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.47 Section 98.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.47 Records that must be...

  19. Detail of staircase (stepped ramp) and retaining wall at West ...

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

    Detail of staircase (stepped ramp) and retaining wall at West 102nd Street, soccer field at right, looking south, with London Plane trees surrounding field. - Henry Hudson Parkway, Extending 11.2 miles from West 72nd Street to Bronx-Westchester border, New York County, NY

  20. 50 CFR Table 11 to Part 679 - BSAI Retainable Percentages

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false BSAI Retainable Percentages 11 Table 11 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE...

  1. Attracting and Retaining Teachers: A Question of Motivation

    ERIC Educational Resources Information Center

    Muller, Karin; Alliata, Roberta; Benninghoff, Fabienne

    2009-01-01

    Attracting and retaining competent teachers is a key concern when it comes to managing the supply and demand for teachers. This article examines the motivation that prompts people to enter or leave the teaching profession with the aim of identifying a decision framework for defining teacher policies. The results are based on the teacher workforce…

  2. Retaining Reluctant Learners in ABE through the Student Intake Period.

    ERIC Educational Resources Information Center

    Pennsylvania State Univ., University Park. Inst. for the Study of Adult Literacy.

    A project sought to determine if reluctant learners, about 30 percent of the adult basic education (ABE) population, can be retained in ABE classes through accommodations in the program structure and more effective teacher/counselor intervention. The project was based on earlier research findings that most ABE learners who drop out do so in the…

  3. Portable conduit retention apparatus for releasably retaining a conduit therein

    DOEpatents

    Metzger, R.H.

    1998-07-07

    Portable conduit retention apparatus is described for releasably retaining a conduit therein. The apparatus releasably retains the conduit out of the way of nearby personnel and equipment. The apparatus includes a portable support frame defining a slot therein having an open mouth portion in communication with the slot for receiving the conduit through the open mouth portion and into the slot. A retention bar is pivotally connected to the support frame adjacent the mouth portion for releasably retaining the conduit in the slot. The retention bar freely pivots to a first position, so that the mouth portion is unblocked in order that the conduit is received through the mouth portion and into the slot. In addition, the retention bar freely pivots to a second position, so that the mouth portion is blocked in order that the conduit is retained in the slot. The conduit is released from the slot by pivoting the retention bar to the first position to unblock the mouth portion and thereafter manipulating the conduit from the slot and through the mouth portion. The apparatus may further include a mounting member attached to the support frame for mounting the apparatus on a vertical support surface. Another embodiment of the apparatus includes a shoe assembly of predetermined weight removably connected to the support frame for resting the apparatus on a floor in such a manner that the apparatus is substantially stationary on the floor. 6 figs.

  4. Portable conduit retention apparatus for releasably retaining a conduit therein

    DOEpatents

    Metzger, Richard H.

    1998-01-01

    Portable conduit retention apparatus for releasably retaining a conduit therein. The apparatus releasably retains the conduit out of the way of nearby personnel and equipment. The apparatus includes a portable support frame defining a slot therein having an open mouth portion in communication with the slot for receiving the conduit through the open mouth portion and into the slot. A retention bar is pivotally connected to the support frame adjacent the mouth portion for releasably retaining the conduit in the slot. The retention bar freely pivots to a first position, so that the mouth portion is unblocked in order that the conduit is received through the mouth portion and into the slot. In addition, the retention bar freely pivots to a second position, so that the mouth portion is blocked in order that the conduit is retained in the slot. The conduit is released from the slot by pivoting the retention bar to the first position to unblock the mouth portion and thereafter manipulating the conduit from the slot and through the mouth portion. The apparatus may further include a mounting member attached to the support frame for mounting the apparatus on a vertical support surface. Another embodiment of the apparatus includes a shoe assembly of predetermined weight removably connected to the support frame for resting the apparatus on a floor in such a manner that the apparatus is substantially stationary on the floor.

  5. Rheology and retained gas measurements in Hanford tank 101-SY

    SciTech Connect

    Shepard, C.L.; Alzheimer, J.M.; Terrones, G.

    1995-12-31

    Several high-level radioactive waste tanks at the Hanford site are known to produce flammable gases. The best known of these tanks is tank 241-SY-101, and to mitigate the safety concerns associated with flammable gas release from this tank, a mixer pump was installed in mid-1993 to mix the waste contents and thereby eliminate or reduce the capability of the waste to retain gas. The mixer pump has proven very effective and only needs to be operated for 30 min about every other day. Large periodic gas release events no longer occur in this tank. However, specific information about the Theological character of the mixed waste and the amount of retained gas has been lacking. In order to determine the amount of gas still retained in the waste and the rheology of the mixed fluid, which is important in establishing the capability of the waste for retaining gas, two instruments were developed to probe the waste in situ. These instruments were the ball rheometer and the void fraction instrument (VFI).

  6. 40 CFR 98.47 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.47 Section 98.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.47 Records that must be...

  7. 40 CFR 98.47 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained. 98.47 Section 98.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.47 Records that must be...

  8. 40 CFR 98.47 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Records that must be retained. 98.47 Section 98.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.47 Records that must be...

  9. From Freshman to Graduate: Recruiting and Retaining Minority Students

    ERIC Educational Resources Information Center

    Hobson-Horton, Lisa D.; Owens, Lula

    2004-01-01

    The purpose of this research project was to identify methods to retain minority teacher education candidates and identify curricular and environmental factors that affect recruitment and retention of minority teacher education candidates and student teachers. Because of the low enrollment of minority students in the department in comparison to the…

  10. 40 CFR 98.447 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained. 98.447 Section 98.447 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Geologic Sequestration of Carbon Dioxide § 98.447 Records...

  11. 40 CFR 98.447 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Records that must be retained. 98.447 Section 98.447 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Geologic Sequestration of Carbon Dioxide § 98.447 Records...

  12. 40 CFR 98.447 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.447 Section 98.447 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Geologic Sequestration of Carbon Dioxide § 98.447 Records...

  13. 40 CFR 98.347 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.347 Section 98.347 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills § 98.347 Records that must...

  14. 40 CFR 98.347 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Records that must be retained. 98.347 Section 98.347 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills § 98.347 Records that must...

  15. 40 CFR 98.347 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Records that must be retained. 98.347 Section 98.347 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills § 98.347 Records that must...

  16. 40 CFR 98.347 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained. 98.347 Section 98.347 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills § 98.347 Records that must...

  17. 40 CFR 98.347 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.347 Section 98.347 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills § 98.347 Records that must...

  18. 40 CFR 98.467 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.467 Section 98.467 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Waste Landfills § 98.467 Records that must...

  19. Structural analysis of a thermal insulation retainer assembly

    NASA Technical Reports Server (NTRS)

    Greene, William H.; Gray, Carl E., Jr.

    1989-01-01

    In January 1989 an accident occurred in the National Transonic Facility wind tunnel at NASA Langley Research Center that was believed to be caused by the failure of a thermal insulation retainer. A structural analysis of this retainer assembly was performed in order to understand the possible failure mechanisms. Two loading conditions are important and were considered in the analysis. The first is the centrifugal force due to the fact that this retainer is located on the fan drive shaft. The second loading is a differential temperature between the retainer assembly and the underlying shaft. Geometrically nonlinear analysis is required to predict the stiffness of this component and to account for varying contact regions between various components in the assembly. High, local stresses develop in the band part of the assembly near discontinuities under both the centrifugal and thermal loadings. The presence of an aluminum ring during a portion of the part's operating life was found to increase the stresses in other regions of the band. Under the centrifugal load, high bending stresses develop near the intersection of the band with joints in the assembly. These high bending stresses are believed to be the most likely cause for failure of the assembly.

  20. 13. View of the swimming pool retaining wall, the steps, ...

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

    13. View of the swimming pool retaining wall, the steps, ascending to the rock garden, and the Belvedere (less distant view). The view includes the bronze sculpture "Bather at the Seine" by Maillol (Ca. 1921), and a honey locust (Gleditsia triacanthos). - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

  1. 12. View of the swimming pool retaining wall, the steps, ...

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

    12. View of the swimming pool retaining wall, the steps, ascending to the rock garden, and the Belvedere (more distant view). The view includes the bronze sculpture "Bather at the Seine" by Maillol (Ca. 1921), and a honey locust (Gleditsia triacanthos). - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

  2. 40 CFR 98.357 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Records that must be retained. 98.357 Section 98.357 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.357 Records that must...

  3. 40 CFR 98.357 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained. 98.357 Section 98.357 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.357 Records that must...

  4. 40 CFR 98.357 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.357 Section 98.357 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.357 Records that must...

  5. 40 CFR 98.357 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.357 Section 98.357 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.357 Records that must...

  6. Attracting and Retaining High-Quality Professionals in Science Education.

    ERIC Educational Resources Information Center

    Weld, Jeffrey

    1998-01-01

    To attract and retain high-quality teachers, the education system must address science teachers' sense of professional isolation, administrators' lack of receptivity to thoughtful teachers' ideas, egalitarian salary compensation schemes, and lack of professional recognition. An outstanding chemistry teacher-turned-pharmaceutical saleswoman is…

  7. Keeping the Best: A Practical Guide to Retaining Key Employees.

    ERIC Educational Resources Information Center

    Bevan, Stephen; Barber, Linda; Robinson, Dilys

    This book, which is intended to assist human resource professionals and line managers in the United Kingdom, is a practical guide to retaining key employees. Discussed in the introduction are the relationship between downsizing and retention, problems that retention difficulties pose for human resource management, and the effects of retention…

  8. DETAIL VIEW OF SIDEWALK, CLINKER BRICK RETAINING WALL, AND ENTRANCE ...

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

    DETAIL VIEW OF SIDEWALK, CLINKER BRICK RETAINING WALL, AND ENTRANCE WAY TO WILLIAM R. THORSEN HOUSE BY CHARLES & HENRY GREENE, 1909. EAST SIDE OF PIEDMONT AVENUE LOOKING SE. Photograph by Fredrica Drotos and Michael Kelly, July 9, 2006 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  9. 10. Photocopy copy of historic photograph showing retaining wall and ...

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

    10. Photocopy copy of historic photograph showing retaining wall and gabeon of lower dam. Date and photographer unknown. (original in possession of United States Department of Agriculture-Forest Service-Allegheny National Forest) VIEW NORTHEAST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

  10. 40 CFR 98.247 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Tier 4 Calculation Methodology in § 98.37, records of the procedures used to develop estimates of the....246(b), and records of any annual average HHV calculations. (b) If you comply with the mass balance... you must retain under this subpart the records required for the applicable Tier...

  11. 40 CFR 98.87 - Records that must be retained.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) If a CEMS is used to measure CO2 emissions, then you must retain under this subpart the records...-specific clinker CO2 emission factor. (2) Documentation of quarterly calculated kiln-specific CKD CO2... CEMS is not used to measure CO2 emissions, then in addition to the records required by § 98.3(g),...

  12. 40 CFR 98.97 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.97 Section 98.97 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing § 98.97 Records that must...

  13. 40 CFR 98.97 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.97 Section 98.97 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing § 98.97 Records that must...

  14. 40 CFR 98.97 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained. 98.97 Section 98.97 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing § 98.97 Records that must...

  15. Hiring & Retaining More Women: The Advantages to Law Enforcement Agencies.

    ERIC Educational Resources Information Center

    Lonsway, Kimberly A.

    Hiring and retaining more women provides numerous important advantages to law enforcement agencies. Research conducted in the United States and internationally has clearly documented that following facts: (1) female officers are as competent as their male counterparts and even excel in certain areas of police performance; (2) female officers are…

  16. 31 CFR 203.16 - Retainer and investor depositaries.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... account balance. On the business day that the TSC receives an AOC from a retainer or investor depositary, the TSC will credit the depositary's TIP main account balance for the amount reported on the AOC... debited to the reserve account and credited to the TGA. (b) Late delivery of AOC. If an AOC does...

  17. 9. PHOTO LOOKING SOUTH FROM THE RETAINING WALL ON THE ...

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

    9. PHOTO LOOKING SOUTH FROM THE RETAINING WALL ON THE NORTH ABUTMENT REVEALS THE SOUTHEAST ABUTMENT. DETAILS OF THE CONCRETE WORK ON THE BALUSTRADE ARE ALSO VISIBLE - Delphi Bridge on U.S. Route 421, Spanning Deer Creek at U.S. Route 421, Delphi, Carroll County, IN

  18. 40 CFR 98.237 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.237 Section 98.237 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Petroleum and Natural Gas Systems § 98.237 Records that...

  19. A Market-Driven Approach to Retaining Talent.

    ERIC Educational Resources Information Center

    Cappelli, Peter

    2000-01-01

    Employee retention must be rethought in a free-agent market. Compensation can shape who leaves and stays. Job design and customization can tailor jobs to employee needs. Encouraging social ties among colleagues and selecting appealing locations for workplaces are other ways to retain talented workers. (SK)

  20. Retained faecolith: an avoidable complication of laparoscopic appendicectomy

    PubMed Central

    Knight, Olivia; Brar, Ranjeet; Clark, Jeremy

    2013-01-01

    A 26-year-old woman presented to the accident and emergency department 9 days post laparoscopic appendicectomy for a non-perforated, but gangrenous appendicitis. She was found to have a retained faecolith with a pelvic abscess. This case demonstrates one of the common pitfalls of the laparoscopic appendicectomy and we discuss some technical points to avoid such complications. PMID:24042211

  1. 40 CFR 98.207 - Records that must be retained.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Records that must be retained. 98.207 Section 98.207 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Magnesium Production § 98.207 Records that must be...

  2. 40 CFR 98.207 - Records that must be retained.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Records that must be retained. 98.207 Section 98.207 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Magnesium Production § 98.207 Records that must be...

  3. 40 CFR 98.207 - Records that must be retained.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Records that must be retained. 98.207 Section 98.207 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Magnesium Production § 98.207 Records that must be...

  4. 40 CFR 98.207 - Records that must be retained.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Records that must be retained. 98.207 Section 98.207 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Magnesium Production § 98.207 Records that must be...

  5. 53. Humbug Creek looking downstream from Humbug Diversion Dam. Retaining ...

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

    53. Humbug Creek looking downstream from Humbug Diversion Dam. Retaining wall for canal is visible beginning at left center. Photographer James Eastwood, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  6. Recruiting and Retaining Rural School Administrators. ERIC Digest.

    ERIC Educational Resources Information Center

    Howley, Aimee; Pendarvis, Edwina

    School districts nationwide, but especially rural districts, are finding it hard to recruit and retain administrators. In the past 25 years, administrators have had to address increasing demands for special programs, collaborative decision making, and accountability. In addition, potential for conflict with school boards and various constituencies…

  7. Recruiting and Retaining Physicians in Very Rural Areas

    ERIC Educational Resources Information Center

    Pepper, Carolyn M.; Sandefer, Ryan H.; Gray, Matt J.

    2010-01-01

    Context: Recruiting and retaining physicians is a challenge in rural areas. Growing up in a rural area and completing medical training in a rural area have been shown to predict decisions to practice in rural areas. Little is known, though, about factors that contribute to physicians' decisions to locate in very sparsely populated areas. Purpose:…

  8. Attracting and Retaining Women in Science and Engineering

    ERIC Educational Resources Information Center

    Rosser, Sue V.

    2003-01-01

    Fiscal year 2001 marked an important milestone in policies to attract and retain women in science and engineering. That year, the National Science Foundation (NSF) initiated an awards program called ADVANCE at a funding level of $19 million. The program supports efforts by institutions and individuals to empower women to participate fully in…

  9. 50 CFR Table 11 to Part 679 - BSAI Retainable Percentages

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false BSAI Retainable Percentages 11 Table 11 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Table 11 Table 11 to Part...

  10. Reinforcement learning in supply chains.

    PubMed

    Valluri, Annapurna; North, Michael J; Macal, Charles M

    2009-10-01

    Effective management of supply chains creates value and can strategically position companies. In practice, human beings have been found to be both surprisingly successful and disappointingly inept at managing supply chains. The related fields of cognitive psychology and artificial intelligence have postulated a variety of potential mechanisms to explain this behavior. One of the leading candidates is reinforcement learning. This paper applies agent-based modeling to investigate the comparative behavioral consequences of three simple reinforcement learning algorithms in a multi-stage supply chain. For the first time, our findings show that the specific algorithm that is employed can have dramatic effects on the results obtained. Reinforcement learning is found to be valuable in multi-stage supply chains with several learning agents, as independent agents can learn to coordinate their behavior. However, learning in multi-stage supply chains using these postulated approaches from cognitive psychology and artificial intelligence take extremely long time periods to achieve stability which raises questions about their ability to explain behavior in real supply chains. The fact that it takes thousands of periods for agents to learn in this simple multi-agent setting provides new evidence that real world decision makers are unlikely to be using strict reinforcement learning in practice. PMID:19885962

  11. Fiber-Reinforced Composite Foam

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A two-phase method for making fiber-reinforced compositions was developed to achieve uniform fiber dispersion in a composite matrix. The first phase involved mixing together water, fibers, and a portion of a fiber dispersant to form a viscous composition. The high viscosity imparted by the dispersa...

  12. Fiber reinforced PMR polyimide composites

    NASA Technical Reports Server (NTRS)

    Cavano, P. J.; Winters, W. E.

    1978-01-01

    Commercially obtained PMR-15 polyimide prepregs with S-glass and graphite fiber reinforcements were evaluated along with in-house prepared glass and graphite cloth PMR 2 materials. A novel autoclave approach was conceived and used to demonstrate that both the PMR systems respond to 1.4 MPa (200 psi) autoclave pressures to produce void free composites equivalent to die molded laminates. Isothermal gravimetric analysis and subsequent mechanical property tests indicated that the PMR 2 system was significantly superior in thermo-oxidative stability, and that S-glass reinforcements may contribute to the accelerated degradation of composites at 316 C (600 F) when compared to graphite fiber reinforced composites. Fully reversed bending fatigue experiments were conducted with a type of fixture unused for organic matrix composites. These studies indicated that the graphite fiber composites were clearly superior in fatigue resistance to the glass fiber reinforced material and that PMR matrix composite systems yield performance of the same order as composite materials employing other families of matrices.

  13. Brucite nanoplate reinforced starch bionanocomposites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  14. Method for reinforcing tubing joints

    NASA Technical Reports Server (NTRS)

    Kinzler, J.; Lee, W. S.

    1968-01-01

    Joint repair technique uses a longitudinally split aluminum shield over the joint ferrule and immediately adjacent tubing to reseal or reinforce leaking or weak joints in small tubing. Epoxy resin coating on inside surfaces of the two shield halves provides a tightly sealed bond between shield and tubing.

  15. Stimuli, Reinforcers, and Private Events

    ERIC Educational Resources Information Center

    Nevin, John A.

    2008-01-01

    Radical behaviorism considers private events to be a part of ongoing observable behavior and to share the properties of public events. Although private events cannot be measured directly, their roles in overt action can be inferred from mathematical models that relate private responses to external stimuli and reinforcers according to the same…

  16. Negative Side Effects of Noncontingent Reinforcement.

    ERIC Educational Resources Information Center

    Vollmer, Timothy R.; And Others

    1997-01-01

    Concerns about noncontingent reinforcement (NCR) are illustrated in a case study of a 13-year-old girl with severe mental retardation who was demonstrating severe aggression. Her NCR treatment produced an extinction burst and incidental reinforcement. A brief omission contingency was added to the reinforcement schedule, which resulted in decreased…

  17. Applied Implications of Reinforcement History Effects

    ERIC Educational Resources Information Center

    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…

  18. Conditioned Reinforcement Value and Resistance to Change

    ERIC Educational Resources Information Center

    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…

  19. Choice, Conditioned Reinforcement, and the Prius Effect

    ERIC Educational Resources Information Center

    Fantino, Edmund

    2008-01-01

    Psychologists have long been intrigued with the rationales that underlie our decisions. Similarly, the concept of conditioned reinforcement has a venerable history, particularly in accounting for behavior not obviously maintained by primary reinforcers. The studies of choice and of conditioned reinforcement have often developed in lockstep. Many…

  20. Rational and Mechanistic Perspectives on Reinforcement Learning

    ERIC Educational Resources Information Center

    Chater, Nick

    2009-01-01

    This special issue describes important recent developments in applying reinforcement learning models to capture neural and cognitive function. But reinforcement learning, as a theoretical framework, can apply at two very different levels of description: "mechanistic" and "rational." Reinforcement learning is often viewed in mechanistic terms--as…

  1. Summary report on the design of the retained gas sampler system (retained gas sampler, extruder and extractor)

    SciTech Connect

    Wootan, D.W.; Bolden, R.C.; Bridges, A.E.; Cannon, N.S.; Chastain, S.A.; Hey, B.E.; Knight, R.C.; Linschooten, C.G.; Pitner, A.L.; Webb, B.J.

    1994-09-29

    This document summarizes work performs in Fiscal Year 1994 to develop the three main components of Retained Gas Sampler System (RGSS). These primary components are the Retained Gas Sampler (RGS), the Retained Gas Extruder (RGE), and the Retained Gas Extractor (RGEx). The RGS is based on the Westinghouse Hanford Company (WHC) Universal Sampler design, and includes modifications to reduce gas leakage. The primary data priorities for the RGSS are to measure the void fraction and the flammable gas concentration in the waste sample. Significant progress has been made in developing the RGSS. The RGSS is being developed by WHC to extract a representative waste sample from a Flammable Gas Watch List Tanks and to measure both the amount and composition of free and {open_quotes}bound{close_quotes} gases. Sudden releases of flammable gas mixtures are a safety concern for normal waste storage operations and eventual waste retrieval. Flow visualization testing was used to identify important fluid dynamic issues related to the sampling process. The primary data priorities for the RGSS are to measure the void fraction and the flammable gas concentration in the waste sample. The safety analysis for the RGSS is being performed by Los Alamos National Laboratory and is more than sixty percent (60%) complete.

  2. Buckling of Fiber Reinforced Composite Plates with Nanofiber Reinforced Matrices

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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: 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. The buckling results showed that the NFRM plates buckled at about twice those with conventional matrix.

  3. Automatic tuning of the reinforcement function

    SciTech Connect

    Touzet, C.; Santos, J.M.

    1997-12-31

    The aim of this work is to present a method that helps tuning the reinforcement function parameters in a reinforcement learning approach. Since the proposal of neural based implementations for the reinforcement learning paradigm (which reduced learning time and memory requirements to realistic values) reinforcement functions have become the critical components. Using a general definition for reinforcement functions, the authors solve, in a particular case, the so called exploration versus exploitation dilemma through the careful computation of the RF parameter values. They propose an algorithm to compute, during the exploration part of the learning phase, an estimate for the parameter values. Experiments with the mobile robot Nomad 200 validate their proposals.

  4. A practical strategy for ongoing reinforcer assessment.

    PubMed Central

    Mason, S A; McGee, G G; Farmer-Dougan, V; Risley, T R

    1989-01-01

    There is a need for practical methods of reinforcer assessment that systematically track ongoing changes in clients' preferences. In this study, the effects of a time-efficient reinforcer assessment package were evaluated in a multiple baseline across 3 preschoolers with autism, comparing individualized item selections by experienced teachers with children's presession preferences for items of various sensory qualities. Systematic assessment of children's reinforcers for correct responding virtually eliminated nontargeted maladaptive behaviors, as well as yielding expected improvements in accuracy. The powerful side-effects of potent reinforcers underline the importance of increased attention to reinforcer assessment in research and practice. PMID:2745238

  5. Drill bit assembly for releasably retaining a drill bit cutter

    SciTech Connect

    Glowka, David A.; Raymond, David W.

    2002-01-01

    A drill bit assembly is provided for releasably retaining a polycrystalline diamond compact drill bit cutter. Two adjacent cavities formed in a drill bit body house, respectively, the disc-shaped drill bit cutter and a wedge-shaped cutter lock element with a removable fastener. The cutter lock element engages one flat surface of the cutter to retain the cutter in its cavity. The drill bit assembly thus enables the cutter to be locked against axial and/or rotational movement while still providing for easy removal of a worn or damaged cutter. The ability to adjust and replace cutters in the field reduces the effect of wear, helps maintains performance and improves drilling efficiency.

  6. Complete endoscopic management of a retained bullet in the bladder.

    PubMed

    Friedman, Ariella A; Trinh, Quoc-Dien; Kaul, Sanjeev; Bhandari, Akshay

    2013-01-01

    A 25-year-old male gunshot victim presented at our institution with gross hematuria following Foley catheter insertion. Computed tomography and cystogram did not show a bladder perforation, but were notable for a left ischial fracture and the presence of a bullet within the bladder. After failed attempts at retrieving the bullet with a resectoscope and loop, as well as a cystoscope and stone crusher, a 26 French nephroscope was inserted transurethrally, and the bullet was successfully engaged and removed using a Perc NCircle (Cook Medical, Bloomington, IN) grasper. The extra-peritoneal injury was managed conservatively with catheter drainage. To our knowledge, this represents the first case of successful transurethral management of a retained intravesical bullet. Such an approach may benefit patients with retained intravesical bullets or other challenging intravesical foreign bodies and may be helpful in select circumstances to spare patients from more extensive surgeries. PMID:23671506

  7. Complete endoscopic management of a retained bullet in the bladder

    PubMed Central

    Friedman, Ariella A.; Trinh, Quoc-Dien; Kaul, Sanjeev; Bhandari, Akshay

    2013-01-01

    A 25-year-old male gunshot victim presented at our institution with gross hematuria following Foley catheter insertion. Computed tomography and cystogram did not show a bladder perforation, but were notable for a left ischial fracture and the presence of a bullet within the bladder. After failed attempts at retrieving the bullet with a resectoscope and loop, as well as a cystoscope and stone crusher, a 26 French nephroscope was inserted transurethrally, and the bullet was successfully engaged and removed using a Perc NCircle (Cook Medical, Bloomington, IN) grasper. The extra-peritoneal injury was managed conservatively with catheter drainage. To our knowledge, this represents the first case of successful transurethral management of a retained intravesical bullet. Such an approach may benefit patients with retained intravesical bullets or other challenging intravesical foreign bodies and may be helpful in select circumstances to spare patients from more extensive surgeries. PMID:23671506

  8. Removal of Retained Descemets Membrane Using Femtosecond Laser

    PubMed Central

    May, William; Alrashidi, Sultan; Daoud, Yassine J.

    2016-01-01

    We present a unique method of retrocorneal membrane removal with a femtosecond laser (FSL). A 22-year-old male who had undergone penetrating keratoplasty had a retained retrocorneal membrane and a double anterior chamber postoperatively. The membrane was dissected completely with the FSL and the free-floating membrane was removed. Histopathological evaluation confirmed the diagnosis of retained Descemets membrane (DM). There was improvement in uncorrected visual acuity from 20/300 to 20/50. Central corneal endothelial cell count was 810 cells/mm2 preoperatively and 778 cells/mm2 postoperatively. Inadvertent retention of DM may be safely treated with the FSL. Clarity and viability of the existing graft can be maintained. PMID:27555712

  9. Retained placenta: will medical treatment ever be possible?

    PubMed

    Akol, Achier D; Weeks, Andrew D

    2016-05-01

    The standard treatment for retained placenta is manual removal whatever its subtype (adherens, trapped or partial accreta). Although medical treatment should reduce the risk of anesthetic and surgical complications, they have not been found to be effective. This may be due to the contrasting uterotonic needs of the different underlying pathologies. In placenta adherens, oxytocics have been used to contract the retro-placental myometrium. However, if injected locally through the umbilical vein, they bypass the myometrium and perfuse directly into the venous system. Intravenous injection is an alternative but exacerbates a trapped placenta. Conversely, for trapped placentas, a relaxant could help by resolving cervical constriction, but would worsen the situation for placenta adherens. This confusion over medical treatment will continue unless we can find a way to diagnose the underlying pathology. This will allow us to stop treating the retained placenta as a single entity and to deliver targeted treatments. PMID:26765548

  10. Implant-retained craniofacial prostheses for facial defects

    PubMed Central

    Federspil, Philipp A.

    2012-01-01

    Craniofacial prostheses, also known as epistheses, are artificial substitutes for facial defects. The breakthrough for rehabilitation of facial defects with implant-retained prostheses came with the development of the modern silicones and bone anchorage. Following the discovery of the osseointegration of titanium in the 1950s, dental implants have been made of titanium in the 1960s. In 1977, the first extraoral titanium implant was inserted in a patient. Later, various solitary extraoral implant systems were developed. Grouped implant systems have also been developed which may be placed more reliably in areas with low bone presentation, as in the nasal and orbital region, or the ideally pneumatised mastoid process. Today, even large facial prostheses may be securely retained. The classical atraumatic surgical technique has remained an unchanged prerequisite for successful implantation of any system. This review outlines the basic principles of osseointegration as well as the main features of extraoral implantology. PMID:22073096

  11. Retained Sponge: A Rare Complication in Acetabular Osteosinthesis

    PubMed Central

    Chana-Rodríguez, Francisco; Mañanes, Rubén Pérez; Rojo-Manaute, José; Moran-Blanco, Luz María; Vaquero-Martín, Javier

    2015-01-01

    Retained sponges after a surgical treatment of polytrauma may cause a broad spectrum of clinical symptoms and present a difficult diagnostic problem. We report a case of retained surgical sponge in a 35-year-old man transferred from another hospital, that sustained a open acetabular fracture. The fracture was reduced through a limited ilio-inguinal approach. After 4 days, he presented massive wound dehiscence of the surgical approach. An abdominal CT scan showed, lying adjacent to the outer aspect of the left iliac crest, a mass of 10 cm, identified as probable foreign body. The possibility of this rare complication should be in the differential diagnosis of any postoperative patient who presents with pain, infection, or palpable mass. PMID:26312116

  12. Removal of Retained Descemets Membrane Using Femtosecond Laser.

    PubMed

    May, William; Alrashidi, Sultan; Daoud, Yassine J

    2016-01-01

    We present a unique method of retrocorneal membrane removal with a femtosecond laser (FSL). A 22-year-old male who had undergone penetrating keratoplasty had a retained retrocorneal membrane and a double anterior chamber postoperatively. The membrane was dissected completely with the FSL and the free-floating membrane was removed. Histopathological evaluation confirmed the diagnosis of retained Descemets membrane (DM). There was improvement in uncorrected visual acuity from 20/300 to 20/50. Central corneal endothelial cell count was 810 cells/mm(2) preoperatively and 778 cells/mm(2) postoperatively. Inadvertent retention of DM may be safely treated with the FSL. Clarity and viability of the existing graft can be maintained. PMID:27555712

  13. Water-retaining barrier and method of construction

    DOEpatents

    Adams, Melvin R.; Field, Jim G.

    1996-01-01

    An agricultural barrier providing a medium for supporting plant life in an arid or semi-arid land region having a ground surface, the barrier being disposed on native soil of the region, the barrier including: a first layer composed of pieces of basalt, the first layer being porous and being in contact with the native soil; a porous second layer of at least one material selected from at least one of sand and gravel, the second layer being less porous than, and overlying, the first layer; and a porous third layer containing soil which favors plant growth, the third layer being less porous than, and overlying, the second layer and having an exposed upper surface, wherein the porosities of the second and third layers differ from one another by an amount which impedes transport of soil from the first layer into the second layer. Soil for the third layer may be provided by washing salinated or contaminated soil with water and using the washed soil for the third layer.

  14. Water-retaining barrier and method of construction

    DOEpatents

    Adams, M.R.; Field, J.G.

    1996-02-20

    An agricultural barrier is disclosed which provides a medium for supporting plant life in an arid or semi-arid land region having a ground surface. The barrier is disposed on native soil of the region. The barrier includes a first porous layer composed of pieces of basalt, and is in contact with the native soil. There is a less porous second layer of at least one material selected from at least one of sand and gravel. The second layer overlies the first layer. A third layer, less porous than the second layer, contains soil which favors plant growth. The third layer overlies the second layer and has an exposed upper surface. The porosities of the second and third layers differ from one another by an amount which impedes transport of soil from the first layer into the second layer. Soil for the third layer may be provided by washing salinated or contaminated soil with water and using the washed soil for the third layer. 2 figs.

  15. 12. A VIEW LOOKING EAST, FROM ATOP THE RETAINING WALL ...

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

    12. A VIEW LOOKING EAST, FROM ATOP THE RETAINING WALL ON THE NORTHEAST ABUTMENT PROVIDES A COMPANION VIEW TO THE PREVIOUS PHOTOGRAPH. THE CLUB HOUSE, PORTIONS OF THE BOARDWALK, A PICNIC SHELTER AND THE SWIMMING STEPS ARE VISIBLE, ALONG WITH A PORTION OF THE NINETEENTH CENTURY BUILDING ON THE NORTH BANK WHICH IS NOW HOME TO COMMERCIAL ENDEAVORS - Delphi Bridge on U.S. Route 421, Spanning Deer Creek at U.S. Route 421, Delphi, Carroll County, IN

  16. Sodium-retaining effect of insulin in diabetes

    PubMed Central

    Manhiani, M. Marlina

    2012-01-01

    Insulin has long been hypothesized to cause sodium retention, potentially of enough magnitude to contribute to hypertension in obesity, metabolic syndrome, and Type II diabetes. There is an abundance of supportive evidence from correlational analyses in humans, acute insulin infusion studies in humans and animals, and chronic insulin infusion studies in rats. However, the absence of hypertension in human insulinoma patients, and negative results for sodium-retaining or blood pressure effects of chronic insulin infusion in a whole series of dog studies, strongly refute the insulin hypothesis. We recently questioned whether the euglycemic, hyperinsulinemia model used for most insulin infusion studies, including the previous chronic dog studies, was the most appropriate model to test the renal actions of insulin in obesity, metabolic syndrome, and Type II diabetes. In those circumstances, hyperinsulinemia coexists with hyperglycemia. Therefore, we tested the sodium-retaining effect of insulin in chronically instrumented, alloxan-treated diabetic dogs. We used 24 h/day intravenous insulin infusion to regulate plasma insulin concentration. Induction of diabetes (∼400 mg/dl) caused sustained natriuresis and diuresis. However, if we clamped insulin at baseline, control levels, i.e., prevented it from decreasing, then the sustained natriuresis and diuresis were completely reversed, despite the same level of hyperglycemia. We also found that 24 h/day intrarenal insulin infusion had the same effect in diabetic dogs but had no sodium-retaining action in normal dogs. This new evidence that insulin has a sodium-retaining effect during hyperglycemia may have implications for maintaining sodium balance in uncontrolled Type II diabetes. PMID:23034715

  17. Method for residual stress relief and retained austenite destabilization

    DOEpatents

    Ludtka, Gerard M.

    2004-08-10

    A method using of a magnetic field to affect residual stress relief or phase transformations in a metallic material is disclosed. In a first aspect of the method, residual stress relief of a material is achieved at ambient temperatures by placing the material in a magnetic field. In a second aspect of the method, retained austenite stabilization is reversed in a ferrous alloy by applying a magnetic field to the alloy at ambient temperatures.

  18. Thermal shock behavior of fiber-reinforced ceramic composites

    SciTech Connect

    Singh, R.N.; Wang, H.

    1995-10-01

    The influence of fiber type and method of composite fabrication on the thermal shock behavior of 2-D fiber-reinforced ceramic composites is studied. Thermal shock tests are performed using a water quench technique, and thermal shock damage is characterized by both destructive and nondestructive techniques. It is shown that the composites possessed superior resistance to thermal shock damage than the monolithic ceramics. Catastrophic failure due to severe thermal stresses is prevented in composites and a significant portion of their original strength is retained at a quench temperature difference up to 1,000 C. These results along with an analysis of the thermal shock damage mechanism based on the destructive and nondestructive tests is described.

  19. Engaging and Retaining Abused Women in Perinatal Home Visitation Programs

    PubMed Central

    Alhusen, Jeanne L.; Bullock, Linda; Bhandari, Shreya; Ghazarian, Sharon; Udo, Ifeyinwa E.; Campbell, Jacquelyn

    2013-01-01

    OBJECTIVES: Intimate partner violence (IPV) during pregnancy affects 0.9% to 17% of women and affects maternal health significantly. The impact of IPV extends to the health of children, including an increased risk of complications during pregnancy and the neonatal period, mental health problems, and cognitive delays. Despite substantial sequelae, there is limited research substantiating best practices for engaging and retaining high-risk families in perinatal home visiting (HV) programs, which have been shown to improve infant development and reduce maltreatment. METHODS: The Domestic Violence Enhanced Home Visitation Program (DOVE) is a multistate longitudinal study testing the effectiveness of a structured IPV intervention integrated into health department perinatal HV programs. The DOVE intervention, based on an empowerment model, combined 2 evidence-based interventions: a 10-minute brochure-based IPV intervention and nurse home visitation. RESULTS: Across all sites, 689 referrals were received from participating health departments. A total of 339 abused pregnant women were eligible for randomization; 42 women refused, and 239 women were randomly assigned (124 DOVE; 115 usual care), resulting in a 71% recruitment rate. Retention rates from baseline included 93% at delivery, 80% at 3 months, 76% at 6 months, and 72% at 12 months. CONCLUSIONS: Challenges for HV programs include identifying and retaining abused pregnant women in their programs. DOVE strategies for engaging and retaining abused pregnant women should be integrated into HV programs’ federal government mandates for the appropriate identification and intervention of women and children exposed to IPV. PMID:24187115

  20. Relationships between soil physicochemical, microbiological properties, and nutrient release in buffer soils compared to field soils.

    PubMed

    Stutter, Marc I; Richards, Samia

    2012-01-01

    The retention of nutrients in narrow, vegetated riparian buffer strips (VBS) is uncertain and underlying processes are poorly understood. Evidence suggests that buffer soils are poor at retaining dissolved nutrients, especially phosphorus (P), necessitating management actions if P retention is not to be compromised. We sampled 19 buffer strips and adjacent arable field soils. Differences in nutrient retention between buffer and field soils were determined using a combined assay for release of dissolved P, N, and C forms and particulate P. We then explored these differences in relation to changes in soil bulk density (BD), moisture, organic matter by loss on ignition (OM), and altered microbial diversity using molecular fingerprinting (terminal restriction fragment length polymorphism [TRFLP]). Buffer soils had significantly greater soil OM (89% of sites), moisture content (95%), and water-soluble nutrient concentrations for dissolved organic C (80%), dissolved organic N (80%), dissolved organic P (55%), and soluble reactive P (70%). Buffer soils had consistently smaller bulk densities than field soils. Soil fine particle release was generally greater for field than buffer soils. Significantly smaller soil bulk density in buffer soils than in adjacent fields indicated increased porosity and infiltration in buffers. Bacterial, archaeal, and fungal communities showed altered diversity between the buffer and field soils, with significant relationships with soil BD, moisture, OM, and increased solubility of buffer nutrients. Current soil conditions in VBS appear to be leading to potentially enhanced nutrient leaching via increasing solubility of C, N, and P. Manipulating soil microbial conditions (by management of soil moisture, vegetation type, and cover) may provide options for increasing the buffer storage for key nutrients such as P without increasing leaching to adjacent streams. PMID:22370402

  1. Investigation of Selectively-Reinforced Metallic Lugs

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.; Abada, Christopher H.

    2007-01-01

    An investigation of the effects of material and geometric variables on the response of U-shaped band-reinforced metallic lugs was performed. Variables studied were reinforcement, adhesive and metallic lug mechanical properties, hole diameter, reinforcement and adhesive thickness, and the distance from the hole s center to the end of the lug. Generally, U-shaped band reinforced lugs exhibited superior performance than non-reinforced lugs, that is higher load at the conventional lug design criteria of four percent hole elongation. Depending upon the reinforcement configuration the increase in load may be negligible to 15 or 20 percent. U-shaped band reinforcement increases lug load carrying capability primarily through two mechanisms; increasing the slope of the response curve after the initial knee and restraining overall deformation of the metallic portion of the lug facilitating increased yielding of metallic material between the hole and the edge of the metallic portion of the lug.

  2. Incisional Reinforcement in High-Risk Patients

    PubMed Central

    Feldmann, Timothy F.; Young, Monica T.; Pigazzi, Alessio

    2014-01-01

    Hernia formation after surgical procedures continues to be an important cause of surgical morbidity. Incisional reinforcement at the time of the initial operation has been used in some patient populations to reduce the risk of subsequent hernia formation. In this article, reinforcement techniques in different surgical wounds are examined to identify situations in which hernia formation may be prevented. Mesh use for midline closure, pelvic floor reconstruction, and stoma site reinforcement is discussed. Additionally, the use of retention sutures, closure of the open abdomen, and reinforcement after component separation are examined using current literature. Although existing studies do not support the routine use of mesh reinforcement for all surgical incisions, certain patient populations appear to benefit from reinforcement with lower rates of subsequent hernia formation. The identification and characterization of these groups will guide the future use of mesh reinforcement in surgical incisions. PMID:25435823

  3. Restriction of Phase Transformation in Carbon Nanotube-Reinforced Yttria-Stabilized Zirconia

    NASA Astrophysics Data System (ADS)

    Mohapatra, Pratyasha; Rawat, Siddharth; Mahato, Neelima; Balani, Kantesh

    2015-07-01

    The present research aims to investigate the effect of multi-walled carbon nanotube (MWNT) reinforcement on the mechanism of transformation toughening in zirconia matrix, and consequently, its fracture toughness. Monoclinic zirconia (un-doped ZrO2), partially stabilized zirconia (3 mol pct yttria-stabilized zirconia (3 mol pct YSZ)), and fully stabilized cubic zirconia (8 mol pct YSZ) with and without 6 vol pct MWNT-reinforced nanocomposites were processed via multi-stage spark plasma sintering. Phase analysis of powders, and sintered and crushed pellets performed using X-ray diffraction reveals the absence of any phase transformation in monoclinic ZrO2, 8 mol pct YSZ and their MWNT-reinforced nanocomposites upon application of stress by means of crushing. However, a significant decrease in the stress-induced phase transformation (81.1 pct metastable tetragonal phase retained with 6 vol pct MWNT reinforcement when compared to that of 68.4 pct tetragonal phase in 3 mol pct YSZ) is observed in the crushed pellet samples of partially stabilized zirconia upon 6 vol pct MWNT reinforcement. Transmission electron microscopy has been utilized for complementary phase analysis. Evaluation of mechanical properties indicates enhancement in fracture toughness (~23.6 to 26.4 pct) with the incorporation of 6 vol pct MWNT. Isolation of the net toughening contribution suggests that MWNT toughening mechanisms are ~3.8 times more effective than transformation toughening in enhancing the fracture toughness of YSZ/MWNT nanocomposites.

  4. Using the NRCS National Soils Information System (NASIS) to provide soil hydraulic properties for engineering applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern agricultural, biological, and environmental engineers have a multitude of uses for soil hydraulic parameters that quantify the ability of soils and sediments to retain and transmit water. These parameters are difficult and costly to obtain, especially if large areas of land need to be charac...

  5. Alumina-Reinforced Zirconia Composites

    NASA Technical Reports Server (NTRS)

    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.

  6. 18 CFR 367.4360 - Account 436, Appropriations of retained earnings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., Appropriations of retained earnings. 367.4360 Section 367.4360 Conservation of Power and Water Resources FEDERAL... NATURAL GAS ACT Retained Earnings Accounts § 367.4360 Account 436, Appropriations of retained earnings. This account must include appropriations of retained earnings as follows: (a) Appropriations...

  7. Conditioned Reinforcement Value and Resistance to Change

    PubMed Central

    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 extinction. Observing responses in both components intermittently produced 15 s of a stimulus associated with the VI schedule (i.e., S+). In the first experiment, a lower-valued conditioned reinforcer and a higher rate of primary reinforcement were arranged in one component by adding response-independent food deliveries uncorrelated with S+. In the second experiment, one component arranged a lower valued conditioned reinforcer but a higher rate of primary reinforcement by increasing the probability of VI schedule periods relative to extinction periods. In the third experiment, the two observing-response components provided similar rates of primary reinforcement but arranged different valued conditioned reinforcers. Across the three experiments, observing-response rates were typically higher in the component associated with the higher valued conditioned reinforcer. Resistance to change was not affected by conditioned reinforcement value, but was an orderly function of the rate of primary reinforcement obtained in the two components. One interpretation of these results is that S+ value does not affect response strength and that S+ deliveries increase response rates through a mechanism other than reinforcement. Alternatively, because resistance to change depends on the discriminative stimulus–reinforcer relation, the failure of S+ value to impact resistance to change could have resulted from a lack of transfer of S+ value to the broader discriminative context. PMID:18540215

  8. Wax Reinforces Honeycomb During Machining

    NASA Technical Reports Server (NTRS)

    Towell, Timothy W.; Fahringer, David T.; Vasquez, Peter; Scheidegger, Alan P.

    1995-01-01

    Method of machining on conventional metal lathe devised for precise cutting of axisymmetric contours on honeycomb cores made of composite (matrix/fiber) materials. Wax filling reinforces honeycomb walls against bending and tearing while honeycomb being contoured on lathe. Innovative method of machining on lathe involves preparation in which honeycomb is placed in appropriate fixture and the fixture is then filled with molten water-soluble wax. Number of different commercial waxes have been tried.

  9. FEM evaluation of cemented-retained versus screw-retained dental implant single-tooth crown prosthesis

    PubMed Central

    Cicciu, Marco; Bramanti, Ennio; Matacena, Giada; Guglielmino, Eugenio; Risitano, Giacomo

    2014-01-01

    Prosthetic rehabilitation of partial or total edentulous patients is today a challenge for clinicians and dental practitioners. The application of dental implants in order to recover areas of missing teeth is going to be a predictable technique, however some important points about the implant angulation, the stress distribution over the bone tissue and prosthetic components should be well investigated for having final long term clinical results. Two different system of the prosthesis fixation are commonly used. The screw retained crown and the cemented retained one. All of the two restoration techniques give to the clinicians several advantages and some disadvantages. Aim of this work is to evaluate all the mechanical features of each system, through engineering systems of investigations like FEM and Von Mises analyses. The FEM is today a useful tool for the prediction of stress effect upon material and biomaterial under load or strengths. Specifically three different area has been evaluated through this study: the dental crown with the bone interface; the passant screw connection area; the occlusal surface of the two different type of crown. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed an adequate response for both type of prostheses, although cemented retained one showed better results over the occlusal area. PMID:24955150

  10. FEM evaluation of cemented-retained versus screw-retained dental implant single-tooth crown prosthesis.

    PubMed

    Cicciu, Marco; Bramanti, Ennio; Matacena, Giada; Guglielmino, Eugenio; Risitano, Giacomo

    2014-01-01

    Prosthetic rehabilitation of partial or total edentulous patients is today a challenge for clinicians and dental practitioners. The application of dental implants in order to recover areas of missing teeth is going to be a predictable technique, however some important points about the implant angulation, the stress distribution over the bone tissue and prosthetic components should be well investigated for having final long term clinical results. Two different system of the prosthesis fixation are commonly used. The screw retained crown and the cemented retained one. All of the two restoration techniques give to the clinicians several advantages and some disadvantages. Aim of this work is to evaluate all the mechanical features of each system, through engineering systems of investigations like FEM and Von Mises analyses. The FEM is today a useful tool for the prediction of stress effect upon material and biomaterial under load or strengths. Specifically three different area has been evaluated through this study: the dental crown with the bone interface; the passant screw connection area; the occlusal surface of the two different type of crown. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed an adequate response for both type of prostheses, although cemented retained one showed better results over the occlusal area. PMID:24955150

  11. Retained intravitreal lens fragments after phacoemulsification: a clinicopathological correlation

    PubMed Central

    Yeo, L; Charteris, D; Bunce, C; Luthert, P; Gregor, Z

    1999-01-01

    AIMS—To explore the relation between clinical course and timing of vitrectomy with the nature and intensity of intraocular inflammatory response in eyes with retained intravitreal lens fragments following complicated phacoemulsification.
METHODS—Prospective evaluation of 22 eyes with retained lens fragments with emphasis on corneal clarity, uveitis, intraocular pressure (IOP), timing of vitrectomy, and visual outcome. Numbers of different types of inflammatory cells in vitreous washings were counted, masked to clinical details, in three non-overlapping adjacent high power fields. Relations between clinical and pathological findings were assessed.
RESULTS—The IOP was raised in 19 eyes before vitrectomy and remained high in nine postoperatively. The latter had higher median total cell count (104 cells/mm2) than those with normal postoperative IOP (37 cells/mm2) but this difference was not statistically significantly different (p=0.17). Nine of 22 eyes underwent vitrectomy within 1 week of cataract surgery. Median total cell count in these eyes was 20 cells/mm2 compared with 140 cells/mm2 in eyes vitrectomised later—this difference was statistically significant (p <0.001). Final visual acuity was 6/12 or better in 13 eyes, these had fewer intravitreal inflammatory cells than the remaining six with poor visual outcome and no pre-existing cause for this (three patients excluded) (p=0.02). Macrophages were the predominant inflammatory cell type.
CONCLUSION—There was significantly less inflammatory cell activity in eyes which had retained lens fragments removed early (within 1 week). Later removal was associated with persistently elevated IOP and poorer visual outcome.

 PMID:10502573

  12. A Partial Palatal Coverage Overdenture Retained by Zygomatic Implants.

    PubMed

    Schweitzer, Daniel M; Bloom, Mitchell J; Mancia, Gregorio O

    2015-12-01

    Prosthodontic rehabilitation of an atrophic edentulous maxilla can be challenging and is further complicated when multiple risk factors are present. Fixed prostheses require multiple implants for support/retention organized in biomechanically favorable positions in order to afford a good prognosis. Such suitable implant arrangements in an atrophic edentulous ridge can often be difficult to achieve. Removable prostheses require fewer implants for a favorable prognosis and can furthermore take advantage of the additional anatomical structures for support/retention. This clinical treatment will describe the fabrication of a partial palatal coverage overdenture retained by zygomatic implants. PMID:26215793

  13. 6. "TEST STAND NO. 13, RETAINING WALLS & APRON, SECTIONS ...

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

    6. "TEST STAND NO. 1-3, RETAINING WALLS & APRON, SECTIONS & ELEVATIONS." Specifications No. OC11-50-10; Drawing No. 60-09-06; no sheet number within title block. D.O. SERIES 1109/20, Rev. B. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04-353 Eng. 177, Rev. B; Date: 26 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-3, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  14. Combination lower lip prosthesis retained by an intraoral component.

    PubMed

    Zeno, Helios A; Sternberger, Sidney S; Tuminelli, Frank J; Billotte, Michael; Kurtz, Kenneth S

    2013-07-01

    Patients who have had a partial or full surgical resection of the maxillary or mandibular lip experience difficulties with articulation of speech, swallowing, and salivary control. This is further complicated by significant alterations in facial esthetics and lowered self-esteem. This clinical treatment will describe the fabrication of a two-piece tooth-retained maxillofacial prosthesis. An intraoral retentive portion and an extraoral section restoring lip anatomy were attached by retentive elements. This prosthesis restored the patient's esthetics, oral function, and self-esteem. PMID:23387560

  15. Autofrettage: Stress distribution under load and retained stresses after depressurization

    NASA Astrophysics Data System (ADS)

    Avitzur, Boaz

    1992-07-01

    There is a long-standing interest in developing a capability to predict the distribution of retained stresses in thick-walled tubes after the removal of an internal pressure-post autofrettage. In this report, four different methods of calculating such stresses are presented and compared. The methods presented are based on the following assumed yield criteria and deformation conditions: (1) Tresca's yield criterion; (2) Tresca's yield criterion 2/3; (3) Mises' yield criterion in plane-stress; and (4) Mises' yield criterion in plane-strain.

  16. Retained Intra- Thoracic Surgical Pack Mimicking as Recurrent Aspergilloma

    PubMed Central

    Mir, Ruquaya; Singh, Vikram P.

    2012-01-01

    An intrathoracic gossypiboma is a rare condition. We are reporting a case of intrathoracicgossypiboma which was misdiagnosed as a recurrent aspergilloma. In our patient, the gossypiboma manifested as a pleural- based extra pulmonary mass which had a large contact area with the pleura and it displayed an extra pulmonary location. A retained surgical swab (gossypiboma) is a rare but an important complication of an intra- thoracic surgery. The diagnosis is usually overlooked, as in our case, resulting in delay of treatment, complications and a prolonged hospitalization. PMID:23373051

  17. Porous electrolyte retainer for molten carbonate fuel cell

    DOEpatents

    Singh, Raj N.; Dusek, Joseph T.

    1983-06-21

    A porous tile for retaining molten electrolyte within a fuel cell is prepared by sintering particles of lithium aluminate into a stable structure. The tile is assembled between two porous metal plates which serve as electrodes with fuels gases such as H.sub.2 and CO opposite to oxidant gases such as O.sub.2 and CO.sub.2. The tile is prepared with a porosity of 55-65% and a pore size distribution selected to permit release of sufficient molten electrolyte to wet but not to flood the adjacent electrodes.

  18. Porous electrolyte retainer for molten carbonate fuel cell. [lithium aluminate

    DOEpatents

    Singh, R.N.; Dusek, J.T.

    1979-12-27

    A porous tile for retaining molten electrolyte within a fuel cell is prepared by sintering particles of lithium aluminate into a stable structure. The tile is assembled between two porous metal plates which serve as electrodes with fuels gases such as H/sub 2/ and CO opposite to oxidant gases such as O/sub 2/ and CO/sub 2/. The tile is prepared with a porosity of 55 to 65% and a pore size distribution selected to permit release of sufficient molten electrolyte to wet but not to flood the adjacent electrodes.

  19. Sensitivity to relative reinforcer rate in concurrent schedules: independence from relative and absolute reinforcer duration.

    PubMed Central

    McLean, A P; Blampied, N M

    2001-01-01

    Twelve pigeons responded on two keys under concurrent variable-interval (VI) schedules. Over several series of conditions, relative and absolute magnitudes of reinforcement were varied. Within each series, relative rate of reinforcement was varied and sensitivity of behavior ratios to reinforcer-rate ratios was assessed. When responding at both alternatives was maintained by equal-sized small reinforcers, sensitivity to variation in reinforcer-rate ratios was the same as when large reinforcers were used. This result was observed when the overall rate of reinforcement was constant over conditions, and also in another series of concurrent schedules in which one schedule was kept constant at VI ached 120 s. Similarly, reinforcer magnitude did not affect the rate at which response allocation approached asymptote within a condition. When reinforcer magnitudes differred between the two responses and reinforcer-rate ratios were varied, sensitivity of behavior allocation was unaffected although response bias favored the schedule that arranged the larger reinforcers. Analysis of absolute response rates ratio sensitivity to reinforcement occurrred on the two keys showed that this invariance of response despite changes in reinforcement interaction that were observed in absolute response rates on the constant VI 120-s schedule. Response rate on the constant VI 120-s schedule was inversely related to reinforcer rate on the varied key and the strength of this relation depended on the relative magnitude of reinforcers arranged on varied key. Independence of sensitivity to reinforcer-rate ratios from relative and absolute reinforcer magnitude is consistent with the relativity and independence assumtions of the matching law. PMID:11256865

  20. Analyses and design of underground reinforced plastic mortar pipelines

    SciTech Connect

    Abdel-Magid, B.M.

    1986-01-01

    A simplified design procedure for underground Reinforced Plastic Mortar (RPM) pipe is proposed. This procedure is based on finite-element analyses of the pipe-soil system and composite laminate analysis of the pipe. With the proposed method, the designer is able to select the best trench geometry and backfill conditions, to determine the construction effects, and to devise the constituent pipe materials according to the given installation conditions for a reliable and cost-effective design. Existing design methods of underground flexible pipes were evaluated. A thorough investigation of the problems encountered with the RPM pipe is made to study the possible modes and causes of failure. The new design method is based on a composite beam element model to account for the failure modes pertinent to fiberglass-reinforced plastic pipes. The design procedure and the required soil and pipe materials data are described. It is shown that simpler performance limits are needed and that the proposed design procedure can be fully implemented once these data are provided.

  1. Failure to produce response variability with reinforcement

    PubMed Central

    Schwartz, Barry

    1982-01-01

    Two experiments attempted to train pigeons to produce variable response sequences. In the first, naive pigeons were exposed to a procedure requiring four pecks on each of two keys in any order, with a reinforcer delivered only if a given sequence was different from the preceding one. In the second experiment, the same pigeons were exposed to this procedure after having been trained successfully to alternate between two specific response sequences. In neither case did any pigeon produce more than a few different sequences or obtain more than 50% of the possible reinforcers. Stereotyped sequences developed even though stereotypy was not reinforced. It is suggested that reinforcers have both hedonic and informative properties and that the hedonic properties are responsible for sterotyped repetition of reinforced responses, even when stereotypy is negatively related to reinforcer delivery. PMID:16812263

  2. Graphite fiber reinforced thermoplastic resins

    NASA Technical Reports Server (NTRS)

    Novak, R. C.

    1975-01-01

    Mechanical properties of neat resin samples and graphite fiber reinforced samples of thermoplastic resins were characterized with particular emphasis directed to the effects of environmental exposure (humidity, temperature and ultraviolet radiation). Tensile, flexural, interlaminar shear, creep and impact strengths were measured for polysulfone, polyarylsulfone and a state-of-the-art epoxy resin samples. In general, the thermoplastic resins exhibited environmental degradation resistance equal to or superior to the reference epoxy resin. Demonstration of the utility and quality of a graphite/thermoplastic resin system was accomplished by successfully thermoforming a simulated compressor blade and a fan exit guide vane.

  3. Chronic fibrous sheath mistaken for retained pacemaker product.

    PubMed

    Nazir, Sheraz A; Hudsmith, Lucy; Newton, James D; Betts, Tim R

    2009-03-01

    A 71-year-old man underwent implantation of a single-chamber system in 1988 for sinoatrial disease, which was then upgraded to dual-chamber 7 years later following recurrent syncope. He presented with pacemaker erosion but without clinical or laboratory evidence of infective endocarditis. The pacemaker system was uneventfully extracted 5 days later via a transfemoral approach using a needle-eye snare. A post-procedure trans-thoracic echocardiogram was performed, which demonstrated an echogenic structure in the right atrium-this was initially felt to be a retained fragment of pacing lead. A short-axis view of the tricuspid valve with a bright linear echo crossing is shown in Figure 1. However, a post-procedural chest X-ray confirmed the absence of any retained intra-cardiac lead. The reverberant cast-like structure noted is a heavily calcified fibrous sheath as the pacing leads were confirmed to be intact at the time of removal. PMID:19147697

  4. Identification and behavior of label-retaining cells in epithelia

    SciTech Connect

    Bickenbach, J.R.

    1982-01-01

    A subpopulation of stem cells has been demonstrated in several renewing tissues. Such cells have a slow cell cycle and provide differentiating cells during normal turnover and during regeneration of the tissue following damage. The presence of slowly-cycling cells in epithelia from regions of skin and oral mucosa was examined by labeling 10-day-old mice and 5-day-old hamsters with tritiated thymidine (/sup 3/H-TdR) and observing the rate at which label was diluted from the basal cells. Label was rapidly diluted by cell division in most cells but a small percentage of basal cells (label-retaining cells, LRCS) was found to retain label for up to ninety days. Electron microscopic autoradiography and ..beta..-glucuronidase histochemistry with autoradiography were used to distinguish slowly-cycling keratinocytes from Langerhans cells. Such findings of slowly-cycling keratinocytes in epithelia with the ability to proliferate in culture and with a direct relationship to patterns of tissue architecture suggest that LRCs in epithelia correspond to stem cells described in other continuously renewing tissues.

  5. Are forensic experts biased by the side that retained them?

    PubMed

    Murrie, Daniel C; Boccaccini, Marcus T; Guarnera, Lucy A; Rufino, Katrina A

    2013-10-01

    How objective are forensic experts when they are retained by one of the opposing sides in an adversarial legal proceeding? Despite long-standing concerns from within the legal system, little is known about whether experts can provide opinions unbiased by the side that retained them. In this experiment, we paid 108 forensic psychologists and psychiatrists to review the same offender case files, but deceived some to believe that they were consulting for the defense and some to believe that they were consulting for the prosecution. Participants scored each offender on two commonly used, well-researched risk-assessment instruments. Those who believed they were working for the prosecution tended to assign higher risk scores to offenders, whereas those who believed they were working for the defense tended to assign lower risk scores to the same offenders; the effect sizes (d) ranged up to 0.85. The results provide strong evidence of an allegiance effect among some forensic experts in adversarial legal proceedings. PMID:23969777

  6. Retained austenite thermal stability in a nanostructured bainitic steel

    SciTech Connect

    Avishan, Behzad; Garcia-Mateo, Carlos; Yazdani, Sasan; Caballero, Francisca G.

    2013-07-15

    The unique microstructure of nanostructured bainite consists of very slender bainitic ferrite plates and high carbon retained austenite films. As a consequence, the reported properties are opening a wide range of different commercial uses. However, bainitic transformation follows the T{sub 0} criteria, i.e. the incomplete reaction phenomena, which means that the microstructure is not thermodynamically stable because the bainitic transformation stops well before austenite reaches an equilibrium carbon level. This article aims to study the different microstructural changes taking place when nanostructured bainite is destabilized by austempering for times well in excess of that strictly necessary to end the transformation. Results indicate that while bainitic ferrite seems unaware of the extended heat treatment, retained austenite exhibits a more receptive behavior to it. - Highlights: • Nanostructured bainitic steel is not thermodynamically stable. • Extensive austempering in these microstructures has not been reported before. • Precipitation of cementite particles is unavoidable at longer austempering times. • TEM, FEG-SEM and XRD analysis were used for microstructural characterization.

  7. Understanding plant root system influences on soil strength and stability

    NASA Astrophysics Data System (ADS)

    Bengough, A. Glyn; Brown, Jennifer L.; Loades, Kenneth W.; Knappett, Jonathan A.; Meijer, Gertjan; Nicoll, Bruce

    2016-04-01

    Keywords: root growth, soil reinforcement, tensile strength Plant roots modify and reinforce the soil matrix, stabilising it against erosion and shallow landslides. Roots mechanically bind the soil particles together and modify the soil hydrology via water uptake, creation of biopores, and modification of the soil water-release characteristic. Key to understanding the mechanical reinforcement of soil by roots is the relation between root strength and root diameter measured for roots in any given soil horizon. Thin roots have frequently been measured to have a greater tensile strength than thick roots, but their strength is also often much more variable. We consider the factors influencing this strength-diameter relationship, considering relations between root tensile strength and root dry density, root water content, root age, and root turnover in several woody and non-woody species. The role of possible experimental artefacts and measurement techniques will be considered. Tensile strength increased generally with root age and decreased with thermal time after excision as a result of root decomposition. Single factors alone do not appear to explain the strength-diameter relationship, and both strength/stiffness and dry density may vary between different layers of tissue within a single root. Results will be discussed to consider how we can achieve a more comprehensive understanding of the variation in root biomechanical properties, and its consequences for soil reinforcement. Acknowledgements: The James Hutton Institute receives funding from the Scottish Government. AGB and JAK acknowledge part funding from EPSRC (EP/M020355/1).

  8. Is the Source of Reinforcement for Naming Multiple Conditioned Reinforcers for Observing Responses?

    ERIC Educational Resources Information Center

    Longano, Jennifer M.; Greer, R. Douglas

    2015-01-01

    Naming refers to the incidental acquisition of word-object relations as listener and speaker without explicit reinforcement. To investigate possible sources of reinforcement for naming, we examined the effects of a procedure for conditioning reinforcement for observing responses on the emergence of naming in children who previously lacked it. The…

  9. Aggression as Positive Reinforcement in Mice under Various Ratio- and Time-Based Reinforcement Schedules

    ERIC Educational Resources Information Center

    May, Michael E.; Kennedy, Craig H.

    2009-01-01

    There is evidence suggesting aggression may be a positive reinforcer in many species. However, only a few studies have examined the characteristics of aggression as a positive reinforcer in mice. Four types of reinforcement schedules were examined in the current experiment using male Swiss CFW albino mice in a resident-intruder model of aggression…

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  12. Quench Crucibles Reinforced with Metal

    NASA Technical Reports Server (NTRS)

    Holmes, Richard R.; Carrasquillo, Edgar; O'Dell, J. Scott; McKehnie, N.

    2008-01-01

    Improved crucibles consisting mainly of metal-reinforced ceramic ampules have been developed for use in experiments in which material specimens are heated in the crucibles to various high temperatures, then quenched by, for example, plunging the crucibles into water at room temperature. In a traditional quench crucible, the gap between the ampule and the metal cartridge impedes the transfer of heat to such a degree that the quench rate (the rate of cooling of the specimen) can be too low to produce the desired effect in the specimen. One can increase the quench rate by eliminating the metal cartridge to enable direct quenching of the ampule, but then the thermal shock of direct quenching causes cracking of the ampule. In a quench crucible of the present improved type, there is no gap and no metal cartridge in the traditional sense. Instead, there is an overlay of metal in direct contact with the ampule, as shown on the right side of the figure. Because there is no gap between the metal overlay and the ampule, the heat-transfer rate can be much greater than it is in a traditional quench crucible. The metal overlay also reinforces the ampule against cracking.

  13. Reinforcement learning or active inference?

    PubMed

    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

  14. Reinforcement Learning or Active Inference?

    PubMed Central

    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

  15. Dynamic earth pressure on rigid retaining walls induced by a neighboring machine foundation, by the meshless local Petrov-Galerkin method

    NASA Astrophysics Data System (ADS)

    Veiskarami, Mehdi; Bahar, Arash; Zandi Lak, Erfan

    2015-12-01

    Dynamic earth pressure induced by machine foundations on a neighboring retaining wall is analyzed with emphasis on factors which control the intensity and location of the design forces. The meshless local Petrov-Galerkin (MLPG) method is used to analyze the problem for a variety of retaining wall and machine foundation geometries. The soil medium is assumed to be homogeneous and visco-elastic. The machine foundation is idealized as a harmonic sinusoidal dynamic force often encountered in practice. A number of analyses have been made to reveal the effect of the loading frequency, the location and size of the foundation and the soil shear wave velocity on the distribution and magnitude of the dynamic earth pressure. Results indicate that there is a critical frequency and a critical location for which the passive pressure takes the maxima in the entire duration of the dynamic load.

  16. Antimony release from contaminated mine soils and its migration in four typical soils using lysimeter experiments.

    PubMed

    Shangguan, Yu-Xian; Zhao, Long; Qin, Yusheng; Hou, Hong; Zhang, Naiming

    2016-11-01

    Antimony (Sb) can pose great risks to the environment in mining and smelting areas. The migration of Sb in contaminated mine soil was studied using lysimeter experiments. The exchangeable concentration of soil Sb decreased with artificial leaching. The concentrations of Sb retained in the subsoil layers (5-25cm deep) were the highest for Isohumosol and Ferrosol and the lowest for Sandy soil. The Sb concentrations in soil solutions decreased with soil depth, and were adequately simulated using a logarithmic function. The Sb migration pattern in Sandy soil was markedly different from the patterns in the other soils which suggested that Sb may be transported in soil colloids. Environmental factors such as water content, soil temperature, and oxidation-reduction potential of the soil had different effects on Sb migration in Sandy soil and Primosol. The high Fe and Mn contents in Ferrosol and Isohumosol significantly decreased the mobility of Sb in these soils. The Na and Sb concentrations in soils used in the experiments positively correlated with each other (P<0.01). The Sb concentrations in soil solutions, the Sb chemical fraction patterns, and the Sb/Na ratios decreased in the order Sandy soil>Primosol>Isohumosol>Ferrosol, and we concluded that the Sb mobility in the soils also decreased in that order. PMID:27395817

  17. The aging nursing workforce: How to retain experienced nurses.

    PubMed

    Cohen, Jeremye D

    2006-01-01

    In the face of an anticipated nursing shortage, healthcare organizations must evaluate their culture, operations, and compensation system to ensure that these elements align with organizational efforts to retain nurses who are approaching retirement age. Management should focus on enhancing elements of job satisfaction and job embeddedness that will motivate nurses to remain both in the workforce and with their employer. Although much of this responsibility falls on the nurse manager, nurse managers are often not provided the necessary support by top management and are neither recognized nor held accountable for nurse turnover. Other retention initiatives can include altering working conditions to reduce both physical and mental stress and addressing issues of employee health and safety. As for compensation, organizations may be well-served by offering senior nursing staff flexible working hours, salary structures that reward experience, and benefit programs that hold value for an aging workforce. PMID:16916117

  18. Retaining local image information in gamut mapping algorithms.

    PubMed

    Zolliker, Peter; Simon, Klaus

    2007-03-01

    Our topic is the potential of combining global gamut mapping with spatial methods to retain the percepted local image information in gamut mapping algorithms. The main goal is to recover the original local contrast between neighboring pixels in addition to the usual optimization of preserving lightness, saturation, and global contrast. Special emphasis is placed on avoiding artifacts introduced by the gamut mapping algorithm itself. We present an unsharp masking technique based on an edge-preserving smoothing algorithm allowing to avoid halo artifacts. The good performance of the presented approach is verified by a psycho-visual experiment using newspaper printing as a representative of a small destination gamut application. Furthermore, the improved mapping properties are documented with local mapping histograms. PMID:17357727

  19. Management of retained products of conception with marked vascularity

    PubMed Central

    Aseeja, Veena

    2012-01-01

    To discuss the management options of retained products of conception (RPOC) with increased vascularity where simple dilatation and curettage may lead to life threatening haemorrhage and endanger the life of the patient. We present a series of three cases that had RPOC with hyper vascularity and were managed with different approaches. A brief review of management options is discussed. Out of three cases of RPOC with hyper vascularity, two cases underwent hysterectomy and one case was managed with methotrexate. From our study and review of literature, we conclude that evaluation of vascularity in all cases of RPOC is mandatory prior to Dilatation&Curettage in order to avoid the dreaded complication of massive haemorrhage. PMID:24592041

  20. Percutaneous Removal of Retained Calculi from the Abdomen

    SciTech Connect

    O'Shea, S.J.; Martin, D.F.

    2003-02-15

    With rising pressure placed on health service resources minimally invasive techniques requiring only short hospital admissions are increasing in importance. We describe the techniques used to remove calculi from the peritoneal cavity which had been retained after surgery and continued to cause clinical problems. In both cases described the calculi lay within abscess cavities associated with fistulous tracks to the skin. The fistulae were dilated to allow passage of therapeutic radiologic and endoscopic equipment enabling manipulation and subsequent extraction of the stones. In both cases removal of the calculi allowed complete resolution of the fistulae and the patients made a full clinical recovery. Removal of gallstones which have escaped into the peritoneum at laparoscopic cholecystectomy leading to sepsis has been described; we describe the novel management of a patient in whom extraction had already been attempted, at another hospital, without success. Removal of an appendicolith, described herein another patient, does not appear to have been reported previously.

  1. Video endoscopy: removal of retained sewing needles from the duodenum.

    PubMed

    Gajbhiye, Ashok S; Gajbhiye, Raj N; Tirupude, Bhupesh H; Bajaj, Prasang P; Gupta, Tarush H

    2013-06-01

    We report an interesting case of a 21-year-old unmarried girl who swallowed six sewing needles. Her complaints were pain in the epigastrium, associated with nausea and vomiting. On examination, there was mild tenderness in the epigastrium. X-ray of the abdomen and endoscopy confirmed the presence of six needles in the duodenum, with tips lodged in the duodenal wall. Psychiatric opinion was sought which was normal. Under video endoscope (Pentax 2.8, EG 27708) guidance with Captura biopsy forceps without spikes (Cook DBF-2.4-160-S), six sewing needles were removed successfully from the duodenum through the endoscope channel without any complications. However, a video endoscopic removal of the retained six needles from duodenum is probably being reported for the first time. PMID:24426531

  2. Apparatus and Process for Controlled Nanomanufacturing Using Catalyst Retaining Structures

    NASA Technical Reports Server (NTRS)

    Nguyen, Cattien (Inventor)

    2013-01-01

    An apparatus and method for the controlled fabrication of nanostructures using catalyst retaining structures is disclosed. The apparatus includes one or more modified force microscopes having a nanotube attached to the tip portion of the microscopes. An electric current is passed from the nanotube to a catalyst layer of a substrate, thereby causing a localized chemical reaction to occur in a resist layer adjacent the catalyst layer. The region of the resist layer where the chemical reaction occurred is etched, thereby exposing a catalyst particle or particles in the catalyst layer surrounded by a wall of unetched resist material. Subsequent chemical vapor deposition causes growth of a nanostructure to occur upward through the wall of unetched resist material having controlled characteristics of height and diameter and, for parallel systems, number density.

  3. Hader bar and clip attachment retained mandibular complete denture

    PubMed Central

    Singh, Kunwarjeet; Gupta, Nidhi; Kapoor, Vikram; Gupta, Ridhimaa

    2013-01-01

    Bar and clip attachments significantly improve the level of satisfaction of denture-wearing patients by enhancing the retention and stability of the prosthesis. These attachments have been most commonly used for connecting the prosthesis to implants, but they can be effectively used to retain tooth-supported prosthesis as well. The primary functions of bar attachments are splinting the abutments together, even distribution of forces to the abutments and supporting areas, guiding the prosthesis into place, improving the retention, stability, support and comfort of the patient. The primary requirement for the use of bar attachments is the availability of sufficient vertical and buccolingual space for the proper placement of the bar, sleeves, teeth arrangement and sufficient thickness of acrylic denture base to minimise incidence of denture fracture in the area of bar assembly. PMID:24145505

  4. Best Practices for Recruiting and Retaining Women in Physics.

    NASA Astrophysics Data System (ADS)

    Murnane, Margaret

    2007-04-01

    Universities make a tremendous investment in faculty, often recruiting and hiring them at great expense. These faculty have highly specialized talents that are needlessly wasted when faculty spend time struggling in a bad environment, or leaving the university. Therefore, there is a great incentive to improve the working environment for female faculty. This talk will highlight specific strategies that departments can use to recruit and retain the best faculty, including female faculty. These strategies have been developed over several years of site visits by the APS Committee on the Status of Women in Physics to physics departments around the US. The mark of a successful departmental climate for women is one in which the enthusiasm and ambition of the women undergraduates is transformed smoothly into successful and ambitious women graduate students, with dynamic, forging-ahead female postdocs, energetic junior women faculty, and productive, happy, senior women faculty who all serve as positive role models.

  5. Attachment systems for implant retained overdentures: a literature review.

    PubMed

    Trakas, Theodoros; Michalakis, Konstantinos; Kang, Kiho; Hirayama, Hiroshi

    2006-03-01

    This article presents a comparison between different attachment systems used to retain and support maxillary and mandibular overdentures in completely edentulous patients. A literature review based on a MEDLINE search limited to English-language articles published from 1988 to the present was performed, and a large number of attachments available in the dental market were reviewed with regard to several factors, including: (1) implant survival rate, (2) marginal bone loss, (3) soft tissue complications, (4) retention, (5) stress distribution, (6) space requirements, (7) maintenance complications, and (8) patient satisfaction. These factors are considered essential for the successful outcome and good long-term prognosis of the prostheses. Selection criteria previously published in the literature are discussed as well. Product names and manufacturers are mentioned only if related to attachment systems, as they are cited in the original articles. PMID:16569958

  6. Intermediate outcome of a cruciate-retaining tibia.

    PubMed

    Mesko, J Wesley; Heath, Sara; Shen, Jianhua

    2013-07-01

    The use of an all-polyethylene tibia in total knee arthroplasty is being revisited as a means to decrease backside polyethylene wear and lessen cost. The Depuy Sigma all-polyethylene tibia (Depuy Orthopedics, Warsaw, Indiana) has been reported with good outcomes at a greater than 10-year interval, whereas the Biomet AGC I beam design (Biomet, Warsaw, Indiana) has had a high failure rate at an early interval. This is a retrospective review of another design. One hundred seventy patients (190 cruciate-retaining total knee replacements) with a Scorpio (Stryker, Mahwah, New Jersey) all-polyethylene implant and tibia were identified in the authors' registry. This implant was chosen for all octogenarians deemed fit for a cruciate-retaining knee and a few septuagenarians who were deemed likely to remain inactive postoperatively for reasons other than knee arthritis. Mean follow-up was 38 months (range, 24-83 months). Mean patient age was 83.1 years (range, 72.7-93.8 years). Twenty-seven patients (29 knees) were lost to follow-up. Nineteen patients (24 knees) died before 24-month follow-up; all implants were in place, and no deaths were associated with the index procedure. Fifty-one patients (55 knees) were followed by telephone interview only and 75 patients (81 knees) by an office visit with radiograph analysis. One tibia revision was performed 2 months postoperatively for an implant placed in extension and varus. No infections, component wear, radiolucent lines, or impending revisions of the remaining cohort occurred. Lower Extremity Activity Scale scores ranged from 2 to 10 (mean score, 6.8), which demonstrated success even in patients with an active lifestyle. This previously unreported design is a promising all-polyethylene tibia alternative for total knee arthroplasty in older patients. PMID:23823045

  7. Reaching (and retaining) Broader Audiences in Citizen Science.

    NASA Astrophysics Data System (ADS)

    Cavalier, D.

    2015-12-01

    Individuals come to citizen science from different perspectives and preferences, and engage in a wide range of projects from data collection to public policy (Irwin 1995, Bonney et al. 2009a). Many participate exclusively online in crowdsourcing projects such as Galaxy Zoo, Fold-It, and Eyewire. Hundreds of thousands gather data on-the-ground for academic andcommunity research projects led by scientists at universities, government agencies/NGOs, and nonprofits. Untold others initiate their own projects in response to local environmental and health issues. All types of citizen science endeavors face challenges around data access and management, around relationships with scientists and project managers, and around making their scientific accomplishments visible as they accumulate over time. Among the most universal and ongoing challenges for all types of citizen science, however, "is attracting and retaining enough participants to make achievement of project goals possible." (Crowston and Prestopnik One known reason for this issue is the reality that individual projects and project types exist in "silos" - as self-segregated groups with particular shared interests (Dickinson et al. 2010). What efforts can be made in digital infrastructures and community building efforts to enable the unprecedented ability to support and retain diverse types of citizen science participation and data exchange between communities? How do we support participation in, and management of, multiple projects; continuity in, and sharing of, a broad and accessible citizen science community; and related social components? This presentation will provide a brief overview of the known barriers to this "utopia" and a snapshot of efforts underway to address many of these barriers.

  8. Quantification of brain perfusion with tracers retained by the brain

    SciTech Connect

    Pupi, A.; Bacciottini, L.; De Cristofaro, M.T.R.; Formiconi, A.R.; Castagnoli, A.

    1991-12-31

    Almost a decade ago, tracers, labelled with {sup 123}I and {sup 99m}Tc, that are retained by the brain, started to be used for studies of regional brain perfusion (regional cerebral blood flow, rCBF). To date, these tracers have been used for brain perfusion imaging with SPECT in brain disorders as well as for physiological activation protocols. Only seldom, however, have they been used in protocols that quantitatively measure rCBF. Nevertheless, comparative studies with perfusion reference tracers have repeatedly demonstrated that the brain uptake of these brain-retained tracers is correlated to perfusion, the major determinant of the distribution of these tracers in the brain. The brain kinetics of {sup 99m}Tc HMPAO, which is the tracer most commonly used, was described with a two-compartment tissue model. The theoretical approach, which is, in itself, sufficient for modeling quantitative measurements with {sup 99m}Tc HMPAO, initially suggested the possibility of empirically narrowing the distance between the brain`s regional uptake of the tracer and rCBF with a linearization algorithm which uses the cerebellum as the reference region. The value of this empirical method is hampered by the fact that the cerebellum can be involved in cerebrovascular disease (i.e. cerebellar diaschisis) as well as in several other brain disorders (e.g. anxiety, and dementia of the Alzheimer type). It also was proposed that different reference regions (occipital, whole slice, or whole brain) should be selected in relation to the brain disorder under study. However, this approach does not solve the main problem because it does not equip us with a reliable tool to evaluate rCBF with a high predictive value, and, at the same time, to reduce intersubject variability. The solution would be to measure a quantitative parameter which directly reflects rCBF, such as the unidirectional influx constant of the freely diffusible flow-limited tracers. 45 refs., 3 figs., 1 tab.

  9. A compliant, high failure strain, fibre-reinforced glass-matrix composite

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.

    1982-01-01

    A glass-matrix composite reinforced by discontinuous graphite fibers was produced by hot pressing glass-powder-impregnated two-dimensional arrays of in-plane randomly oriented graphite fibers held together by approximately 5-10% by weight of organic binder (generally polyester). The composite tensile behavior is characterized by a highly nonlinear stress-strain curve which differs markedly from that of either unreinforced glass or a similarly reinforced epoxy-matrix composite. By virtue of this nonlinearity, the composite is able to redistribute applied stresses to achieve a high load-carrying capacity. The fibrous microstructure and the low fiber-matrix bond provide a mechanism for achieving high fracture toughness and unusually high compliance. For a 96%-silica-matrix composite, the strength is retained to over 1000 C.

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

    NASA Astrophysics Data System (ADS)

    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. Operant Variability and the Power of Reinforcement

    ERIC Educational Resources Information Center

    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,…

  12. An Analysis of "Reinforcement" History Effects

    ERIC Educational Resources Information Center

    Okouchi, Hiroto; Lattal, Kennon A.

    2006-01-01

    Four pigeons were exposed to two tandem variable-interval differential-reinforcement-of-low-rate schedules under different stimulus conditions. The values of the tandem schedules were adjusted so that reinforcement rates in one stimulus condition were higher than those in the other, even though response rates in the two conditions were nearly…

  13. Choice, changing over, and reinforcement delays.

    PubMed Central

    Shahan, T A; Lattal, K A

    2000-01-01

    In three experiments, pigeons were used to examine the independent effects of two normally confounded delays to reinforcement associated with changing between concurrently available variable-interval schedules of reinforcement. In Experiments 1 and 2, combinations of changeover-delay durations and fixed-interval travel requirements were arranged in a changeover-key procedure. The delay from a changeover-produced stimulus change to a reinforcer was varied while the delay between the last response on one alternative and a reinforcer on the other (the total obtained delay) was held constant. Changeover rates decreased as a negative power function of the total obtained delay. The delay between a changeover-produced stimulus change had a small and inconsistent effect on changeover rates. In Experiment 3, changeover delays and fixed-interval travel requirements were arranged independently. Changeover rates decreased as a negative power function of the total obtained delay despite variations in the delay from a change in stimulus conditions to a reinforcer. Periods of high-rate responding following a changeover, however, were higher near the end of the delay from a change in stimulus conditions to a reinforcer. The results of these experiments suggest that the effects of changeover delays and travel requirements primarily result from changes in the delay between a response at one alternative and a reinforcer at the other, but the pattern of responding immediately after a changeover depends on the delay from a changeover-produced change in stimulus conditions to a reinforcer. PMID:11218228

  14. A molar theory of reinforcement schedules

    PubMed Central

    Rachlin, Howard

    1978-01-01

    Behavior of subjects exposed to concurrent and individual interval and ratio schedules of reinforcement may be described in terms of a set of expressions relating the value of responses to their durations, a feedback equation relating reinforcement to response duration, and the assumption that subjects allocate their time among various responses so as to maximize value. PMID:16812114

  15. Conditioned reinforcement and information theory reconsidered.

    PubMed

    Shahan, Timothy A; Cunningham, Paul

    2015-03-01

    The idea that stimuli might function as conditioned reinforcers because of the information they convey about primary reinforcers has a long history in the study of learning. However, formal application of information theory to conditioned reinforcement has been largely abandoned in modern theorizing because of its failures with respect to observing behavior. In this paper we show how recent advances in the application of information theory to Pavlovian conditioning offer a novel approach to conditioned reinforcement. The critical feature of this approach is that calculations of information are based on reductions of uncertainty about expected time to primary reinforcement signaled by a conditioned reinforcer. Using this approach, we show that previous failures of information theory with observing behavior can be remedied, and that the resulting framework produces predictions similar to Delay Reduction Theory in both observing-response and concurrent-chains procedures. We suggest that the similarity of these predictions might offer an analytically grounded reason for why Delay Reduction Theory has been a successful theory of conditioned reinforcement. Finally, we suggest that the approach provides a formal basis for the assertion that conditioned reinforcement results from Pavlovian conditioning and may provide an integrative approach encompassing both domains. PMID:25766452

  16. Reinforcing aluminum alloys with high strength fibers

    NASA Technical Reports Server (NTRS)

    Kolpashnikov, A. I.; Manuylov, V. F.; Chukhin, B. D.; Shiryayev, Y. V.; Shurygin, A. S.

    1982-01-01

    A study is made of the possibility of reinforcing aluminum and aluminum based alloys with fibers made of high strength steel wire. The method of introducing the fibers is described in detail. Additional strengthening by reinforcement of the high alloy system Al - An - Mg was investigated.

  17. Token Reinforcement: A Review and Analysis

    ERIC Educational Resources Information Center

    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…

  18. Teaching Positive Reinforcement on the Internet

    ERIC Educational Resources Information Center

    Grant, Lyle K.

    2004-01-01

    This study is an examination of an Internet-based tutorial that teaches the concept of positive reinforcement. An experimental group of 50 students studied an online tutorial about positive reinforcement, and a control group of 50 students studied an online tutorial in biological psychology. Students in both groups took an 8-item pretest and…

  19. Reinforced rubber composition containing ground coal

    SciTech Connect

    Sperley, R.J.

    1984-10-16

    A reinforced rubber composition is provided comprising a mixture of (a) a sulfur vulcanizable rubber and (b) ground coal having an average mesh size of 25 or more and which produces an aqueous slurry with a pH of less than 7.0, and wherein a metallic reinforcing member is embedded in the rubber mixture of (a) and (b).

  20. Carbon black retention in saturated natural soils: Effects of flow conditions, soil surface roughness and soil organic matter.

    PubMed

    Lohwacharin, J; Takizawa, S; Punyapalakul, P

    2015-10-01

    We evaluated factors affecting the transport, retention, and re-entrainment of carbon black nanoparticles (nCBs) in two saturated natural soils under different flow conditions and input concentrations using the two-site transport model and Kelvin probe force microscopy (KPFM). Soil organic matter (SOM) was found to create unfavorable conditions for the retention. Despite an increased flow velocity, the relative stability of the estimated maximum retention capacity in soils may suggest that flow-induced shear stress forces were insufficient to detach nCB. The KPFM observation revealed that nCBs were retained at the grain boundary and on surface roughness, which brought about substantial discrepancy between theoretically-derived attachment efficiency factors and the ones obtained by the experiments using the two-site transport model. Thus, decreasing ionic strength and increasing solution pH caused re-entrainment of only a small fraction of retained nCB in the soil columns. PMID:26057475

  1. Online learning control by association and reinforcement.

    PubMed

    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

  2. Microstructural characterization of fiber-reinforced composites

    SciTech Connect

    Summerscales, J.

    1998-12-31

    In the past 50 years, great progress has been made in developing artificial fiber-reinforced composite materials, generally using filaments with microscopic diameters. An array of reinforcement forms can be used in commercial applications--with the microstructure being a critical factor in realizing the required properties in a material. This book comprehensively examines the application of advanced microstructural characterization techniques to fiber-reinforced composites. Its contents include: (1) flexible textile composite microstructure; (2) 3-D confocal microscopy of glass fiber-reinforced composites; (3) geometric modeling of yarn and fiber assemblies; (4) characterization of yarn shape in woven fabric composites; (5) quantitative microstructural analysis for continuous fiber composites; (6) electron microscopy of polymer composites; (7) micromechanics of reinforcement using laser raman spectroscopy; and (8) acoustic microscopy of ceramic fiber composites.

  3. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS.

    SciTech Connect

    Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P.; Chang, T.Y.

    2001-03-22

    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.

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

    PubMed Central

    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 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. Reinforcement Sensitivity Underlying Treatment-Seeking Smokers’ Affect, Smoking Reinforcement Motives, and Affective Responses

    PubMed Central

    Cui, Yong; Robinson, Jason D.; Engelmann, Jeffrey M.; Lam, Cho Y.; Minnix, Jennifer A.; Karam-Hage, Maher; Wetter, David W.; Dani, John A.; Kosten, Thomas R.; Cinciripini, Paul M.

    2014-01-01

    Nicotine dependence has been suggested to be related to reinforcement sensitivity, which encompasses behavioral predispositions either to avoid aversive (behavioral inhibition) or to approach appetitive (behavioral activation) stimuli. Reinforcement sensitivity may shape motives for nicotine use and offer potential targets for personalized smoking cessation therapy. However, little is known regarding how reinforcement sensitivity is related to motivational processes implicated in the maintenance of smoking. Additionally, women and men differ in reinforcement sensitivity, and such difference may cause distinct relationships between reinforcement sensitivity and motivational processes for female and male smokers. In this study, we characterized reinforcement sensitivity in relation to affect, smoking-related reinforcement motives, and affective responses, using self-report and psychophysiological measures, in over 200 smokers before treating them. The Behavioral Inhibition/Activation Scales (BIS/BAS; Carver & White, 1994) was used to measure reinforcement sensitivity. In female and male smokers, BIS was similarly associated with negative affect and negative reinforcement of smoking. But positive affect was positively associated with BAS Drive scores in male smokers, and this association was reversed in female smokers. BIS was positively associated with corrugator electromyographic reactivity towards negative stimuli and left frontal electroencephalogram alpha asymmetry. Female and male smokers showed similar relationships for these physiological measures. These findings suggest that reinforcement sensitivity underpins important motivational processes (e.g., affect), and gender is a moderating factor for these relationships. Future personalized smoking intervention, particularly among more dependent treatment-seeking smokers, may experiment to target individual differences in reinforcement sensitivity. PMID:25621416

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

    PubMed

    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

  7. Using Combustion Synthesis to Reinforce Berms and Other Regolith Structures

    NASA Technical Reports Server (NTRS)

    Rodriquez, Gary

    2013-01-01

    , developing a very irregular surface which, like sandpaper, can provide an anchor for loose soil. CS fabrics employ a coarse fiberglass weave that persists as reinforcement for the fired material. The fiberglass softens at a temperature that exceeds the combustion temperature by factors of two to three, and withstands the installation process. This type of structure should be more resistant to rocket blast effects from Lunar landers.

  8. Reinforcer satiation and resistance to change of responding maintained by qualitatively different reinforcers.

    PubMed

    Podlesnik, Christopher A; Shahan, Timothy A

    2009-05-01

    In previous research on resistance to change, differential disruption of operant behavior by satiation has been used to assess the relative strength of responding maintained by different rates or magnitudes of the same reinforcer in different stimulus contexts. The present experiment examined resistance to disruption by satiation of one reinforcer type when qualitatively different reinforcers were arranged in different contexts. Rats earned either food pellets or a 15% sucrose solution on variable-interval 60-s schedules of reinforcement in the two components of a multiple schedule. Resistance to satiation was assessed by providing free access either to food pellets or the sucrose solution prior to or during sessions. Responding systematically decreased more relative to baseline in the component associated with the satiated reinforcer. These findings suggest that when qualitatively different reinforcers maintain responding, relative resistance to change depends upon the relations between reinforcers and disrupter types. PMID:19111914

  9. Reinforcer Satiation and Resistance to Change of Responding Maintained by Qualitatively Different Reinforcers

    PubMed Central

    Podlesnik, Christopher A.; Shahan, Timothy A.

    2008-01-01

    In previous research on resistance to change, differential disruption of operant behavior by satiation has been used to assess the relative strength of responding maintained by different rates or magnitudes of the same reinforcer in different stimulus contexts. The present experiment examined resistance to disruption by satiation of one reinforcer type when qualitatively different reinforcers were arranged in different contexts. Rats earned either food pellets or a 15% sucrose solution on variable-interval 60-s schedules of reinforcement in the two components of a multiple schedule. Resistance to satiation was assessed by providing free access either to food pellets or the sucrose solution prior to or during sessions. Responding systematically decreased more relative to baseline in the component associated with the satiated reinforcer. These findings suggest that when qualitatively different reinforcers maintain responding, relative resistance to change depends upon the relations between reinforcers and disrupter types. PMID:19111914

  10. 26 CFR 20.2036-1 - Transfers with retained life estate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 14 2012-04-01 2012-04-01 false Transfers with retained life estate. 20.2036-1... Transfers with retained life estate. (a) In general. A decedent's gross estate includes under section 2036... money or money's worth (see § 20.2043-1), if the decedent retained or reserved— (1) For his life;...

  11. 26 CFR 20.2036-1 - Transfers with retained life estate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 14 2011-04-01 2010-04-01 true Transfers with retained life estate. 20.2036-1... Transfers with retained life estate. (a) In general. A decedent's gross estate includes under section 2036... money or money's worth (see § 20.2043-1), if the decedent retained or reserved— (1) For his life;...

  12. 26 CFR 20.2036-1 - Transfers with retained life estate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Transfers with retained life estate. 20.2036-1... Transfers with retained life estate. (a) In general. A decedent's gross estate includes under section 2036... money or money's worth (see § 20.2043-1), if the decedent retained or reserved— (1) For his life;...

  13. 26 CFR 20.2036-1 - Transfers with retained life estate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 14 2013-04-01 2013-04-01 false Transfers with retained life estate. 20.2036-1... Transfers with retained life estate. (a) In general. A decedent's gross estate includes under section 2036... money or money's worth (see § 20.2043-1), if the decedent retained or reserved— (1) For his life;...

  14. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  15. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  16. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  17. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  18. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  19. 41 CFR 102-37.270 - May a SASP retain surplus property for its own use?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false May a SASP retain surplus property for its own use? 102-37.270 Section 102-37.270 Public Contracts and Property Management... Property § 102-37.270 May a SASP retain surplus property for its own use? Yes, you can retain...

  20. 41 CFR 102-37.270 - May a SASP retain surplus property for its own use?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false May a SASP retain surplus property for its own use? 102-37.270 Section 102-37.270 Public Contracts and Property Management... Property § 102-37.270 May a SASP retain surplus property for its own use? Yes, you can retain...

  1. 26 CFR 1.636-2 - Production payments retained in leasing transactions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 7 2010-04-01 2010-04-01 true Production payments retained in leasing... payments retained in leasing transactions. (a) Treatment by lessee. In the case of a production payment (as defined in paragraph (a) of § 1.636-3) which is retained by the lessor in a leasing transaction...

  2. 41 CFR 102-37.270 - May a SASP retain surplus property for its own use?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false May a SASP retain surplus property for its own use? 102-37.270 Section 102-37.270 Public Contracts and Property Management... Property § 102-37.270 May a SASP retain surplus property for its own use? Yes, you can retain...

  3. 41 CFR 102-37.270 - May a SASP retain surplus property for its own use?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false May a SASP retain surplus property for its own use? 102-37.270 Section 102-37.270 Public Contracts and Property Management... Property § 102-37.270 May a SASP retain surplus property for its own use? Yes, you can retain...

  4. 41 CFR 102-37.270 - May a SASP retain surplus property for its own use?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false May a SASP retain surplus property for its own use? 102-37.270 Section 102-37.270 Public Contracts and Property Management... Property § 102-37.270 May a SASP retain surplus property for its own use? Yes, you can retain...

  5. 7 CFR 97.17 - Papers of completed application to be retained.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Papers of completed application to be retained. 97.17... LABORATORY TESTING PROGRAMS PLANT VARIETY AND PROTECTION The Application § 97.17 Papers of completed application to be retained. The papers submitted with a completed application shall be retained by the...

  6. 7 CFR 97.17 - Papers of completed application to be retained.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Papers of completed application to be retained. 97.17... LABORATORY TESTING PROGRAMS PLANT VARIETY AND PROTECTION The Application § 97.17 Papers of completed application to be retained. The papers submitted with a completed application shall be retained by the...

  7. Correction of bilateral impacted mandibular canines with a lip bumper for anchorage reinforcement.

    PubMed

    Agarwal, Sachin; Yadav, Sumit; Shah, Neelesh V; Valiathan, Ashima; Uribe, Flavio; Nanda, Ravindra

    2013-03-01

    Multiple treatment options are available to patients with impacted manibular canines in addition to a retained deciduous canine. This article describes the treatment of a prepubertal girl, aged 10 years 6 months, with a skeletal Class I, dental Class II Division 1 malocclusion, retrognathic mandible, deep overbite, proclined maxillary incisors, midline diastema, and bilateral mandibular canine impaction. The orthodontic treatment plan included extraction of the deciduous canine and forced eruption of the impacted canines. A modified lip bumper appliance was used both for forced eruption and to reinforce anchorage. Through the collaborative efforts of an orthodontist and an oral surgeon, an excellent esthetic and functional outcome was achieved. PMID:23452974

  8. Hierarchical Bayesian inverse reinforcement learning.

    PubMed

    Choi, Jaedeug; Kim, Kee-Eung

    2015-04-01

    Inverse reinforcement learning (IRL) is the problem of inferring the underlying reward function from the expert's behavior data. The difficulty in IRL mainly arises in choosing the best reward function since there are typically an infinite number of reward functions that yield the given behavior data as optimal. Another difficulty comes from the noisy behavior data due to sub-optimal experts. We propose a hierarchical Bayesian framework, which subsumes most of the previous IRL algorithms as well as models the sub-optimality of the expert's behavior. Using a number of experiments on a synthetic problem, we demonstrate the effectiveness of our approach including the robustness of our hierarchical Bayesian framework to the sub-optimal expert behavior data. Using a real dataset from taxi GPS traces, we additionally show that our approach predicts the driving behavior with a high accuracy. PMID:25291805

  9. Collaborating Fuzzy Reinforcement Learning Agents

    NASA Technical Reports Server (NTRS)

    Berenji, Hamid R.

    1997-01-01

    Earlier, we introduced GARIC-Q, a new method for doing incremental Dynamic Programming using a society of intelligent agents which are controlled at the top level by Fuzzy Relearning and at the local level, each agent learns and operates based on ANTARCTIC, a technique for fuzzy reinforcement learning. In this paper, we show that it is possible for these agents to compete in order to affect the selected control policy but at the same time, they can collaborate while investigating the state space. In this model, the evaluator or the critic learns by observing all the agents behaviors but the control policy changes only based on the behavior of the winning agent also known as the super agent.

  10. Assessing the value of token reinforcement for individuals with autism.

    PubMed

    Fiske, Kate E; Isenhower, Robert W; Bamond, Meredith J; Delmolino, Lara; Sloman, Kimberly N; LaRue, Robert H

    2015-01-01

    The use of token systems has been supported across a variety of populations, but little research has evaluated the reinforcing value of token systems for individuals with autism. We used progressive-ratio schedules to compare the reinforcing value of an established token system, primary reinforcement, and tokens unpaired with reinforcement. Token systems were variably reinforcing for 2 students with autism and more so than primary reinforcement for 1 student. Results support formal assessment of the effectiveness of token systems. PMID:25930718

  11. Toughness of fiber reinforced shotcrete

    SciTech Connect

    Morgan, D.R.; Chen, L.; Beaupre, D.

    1995-12-31

    Fibers are added to shotcrete to improve energy absorption and impact resistance, to provide crack resistance and crack control, and to provide apparent ductility, i.e., an ability to continue to carry load after the shotcrete matrix has cracked. In order to be able to quantify the benefits of fiber addition, a variety of different toughness measuring systems have been developed in different countries. Most commonly used are flexural toughness systems which determine load vs. deflection responses and relate the area under the curve to some absolute or dimensionless index energy parameter. In North America the ASTM C1018 test method is most commonly used. In Japan the JSCE-SF4 test procedure is used. A variety of procedures have been used in Europe, but the template approach of the Norwegian Guidelines NBP No. 7, seems to be finding favor. This paper briefly assesses the relative advantages and disadvantages of the various methods of characterizing toughness. It then provides recommendations for a new procedure which uses the ASTM C1018 test method for generating the flexural load vs. deflection curve, but analyzes the data using a modified version of the Norwegian template approach. The load vs. deflection curve is directly compared against four residual strength curves and the fiber reinforced shotcrete assigned one of four toughness performance levels. It is believed that this new procedure should provide suitable within and between laboratory reproducibility and be more suitable for purposes of differentiating between different fiber types and addition rates and specifying toughness for fiber reinforced shotcrete products than any of the existing methods.

  12. Comparative Evaluation of Microleakage of Lingual Retainer Wires Bonded with Three Different Lingual Retainer Composites: An In Vitro Study

    PubMed Central

    Vaz, Anna; Patil, Pravinkumar G.

    2014-01-01

    Objective: To evaluate microleakage when two types of retainer wires were bonded with two light cured and a self cured lingual retainer composites. Materials and Methods: Total 120 freshly extracted human mandibular incisor teeth were collected and separated into six subgroups of 20 teeth each. Two different wires, a 0.036 inch hard round stainless steel (HRSS) wire sandblasted at the ends and 0.0175 inch multistranded wire bonded onto the lingual surfaces of the incisors with three different types of composite resins of 3M company; Concise Orthodontic (self-cure), Transbond XT (light-cure) and Transbond LR (light-cure). Specimens were further sealed with a nail varnish, stained with 0.5% basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-composite and wire-composite interfaces. Statistical analysis was performed by Kruskal-Wallis and Mann-Whitney U-tests. Results: For HRSS wire, at the enamel-composite interface, the microleakage was least with Transbond LR followed by Concise Orthodontic and greatest for Transbond XT (p<0.05). At the wire composite interface too, the microleakage was in order of Transbond LR

  13. Non-traditional shape GFRP rebars for concrete reinforcement

    NASA Astrophysics Data System (ADS)

    Claure, Guillermo G.

    existing provisions and standards allowing for a consistent universal norm for all GFRP rebars were reached. This dissertation also presents an evaluation of the structural behavior of reinforced concrete (RC) beams and slabs using the new type of GFRP rebar consisting of a non-traditional hollow-core shape compared to "traditional" solid round rebars with equivalent cross-sectional areas within the framework of two studies, respectively. To validate the design assumptions following ACI 440.1R design guidelines, two conditions were investigated: under-reinforced (failure controlled by rupture of GFRP rebar); and, over-reinforced (failure controlled by crushing of concrete). For comparison, a cyclic three-point bending load test matrix was developed: for beams, 3 under-reinforced and 3 over-reinforced with hollow-core and solid GFRP rebars, respectively, making a total of 12 RC specimens; for slabs, 3 under-reinforced and 3 over-reinforced with hollow-core and 2 types of solid GFRP rebars, respectively, making a total of 18 RC slabs. The studies on GFRP RC beams and slabs concluded that the hollow-core GFRP rebars were as effective as their solid counterpart and ACI 440.1R design guidelines were applicable to predict their performance. It was shown that final design may be controlled by the permissible deflections as governing parameter for elements under service conditions. Also, a final study with a test matrix containing six extra specimens was generated for post-fire residual strength evaluation of fire-exposed GFRP RC slabs along with temperature gradient in the slabs and dynamic mechanical analysis (DMA) investigation on GFRP samples extracted from the fire-exposed slabs. In this study, the ability of GFRP RC slabs to retain structural integrity during a standards fire exposure as well as determining the residual structural capacity were investigated. The residual strength evaluation of the fire-exposed slabs showed a range of results varying between +/- 10%, of the

  14. Sustainable Management in Crop Monocultures: The Impact of Retaining Forest on Oil Palm Yield

    PubMed Central

    Edwards, Felicity A.; Edwards, David P.; Sloan, Sean; Hamer, Keith C.

    2014-01-01

    Tropical agriculture is expanding rapidly at the expense of forest, driving a global extinction crisis. How to create agricultural landscapes that minimise the clearance of forest and maximise sustainability is thus a key issue. One possibility is protecting natural forest within or adjacent to crop monocultures to harness important ecosystem services provided by biodiversity spill-over that may facilitate production. Yet this contrasts with the conflicting potential that the retention of forest exports dis-services, such as agricultural pests. We focus on oil palm and obtained yields from 499 plantation parcels spanning a total of ≈23,000 ha of oil palm plantation in Sabah, Malaysian Borneo. We investigate the relationship between the extent and proximity of both contiguous and fragmented dipterocarp forest cover and oil palm yield, controlling for variation in oil palm age and for environmental heterogeneity by incorporating proximity to non-native forestry plantations, other oil palm plantations, and large rivers, elevation and soil type in our models. The extent of forest cover and proximity to dipterocarp forest were not significant predictors of oil palm yield. Similarly, proximity to large rivers and other oil palm plantations, as well as soil type had no significant effect. Instead, lower elevation and closer proximity to forestry plantations had significant positive impacts on oil palm yield. These findings suggest that if dipterocarp forests are exporting ecosystem service benefits or ecosystem dis-services, that the net effect on yield is neutral. There is thus no evidence to support arguments that forest should be retained within or adjacent to oil palm monocultures for the provision of ecosystem services that benefit yield. We urge for more nuanced assessments of the impacts of forest and biodiversity on yields in crop monocultures to better understand their role in sustainable agriculture. PMID:24638038

  15. Sustainable management in crop monocultures: the impact of retaining forest on oil palm yield.

    PubMed

    Edwards, Felicity A; Edwards, David P; Sloan, Sean; Hamer, Keith C

    2014-01-01

    Tropical agriculture is expanding rapidly at the expense of forest, driving a global extinction crisis. How to create agricultural landscapes that minimise the clearance of forest and maximise sustainability is thus a key issue. One possibility is protecting natural forest within or adjacent to crop monocultures to harness important ecosystem services provided by biodiversity spill-over that may facilitate production. Yet this contrasts with the conflicting potential that the retention of forest exports dis-services, such as agricultural pests. We focus on oil palm and obtained yields from 499 plantation parcels spanning a total of ≈23,000 ha of oil palm plantation in Sabah, Malaysian Borneo. We investigate the relationship between the extent and proximity of both contiguous and fragmented dipterocarp forest cover and oil palm yield, controlling for variation in oil palm age and for environmental heterogeneity by incorporating proximity to non-native forestry plantations, other oil palm plantations, and large rivers, elevation and soil type in our models. The extent of forest cover and proximity to dipterocarp forest were not significant predictors of oil palm yield. Similarly, proximity to large rivers and other oil palm plantations, as well as soil type had no significant effect. Instead, lower elevation and closer proximity to forestry plantations had significant positive impacts on oil palm yield. These findings suggest that if dipterocarp forests are exporting ecosystem service benefits or ecosystem dis-services, that the net effect on yield is neutral. There is thus no evidence to support arguments that forest should be retained within or adjacent to oil palm monocultures for the provision of ecosystem services that benefit yield. We urge for more nuanced assessments of the impacts of forest and biodiversity on yields in crop monocultures to better understand their role in sustainable agriculture. PMID:24638038

  16. Origins of food reinforcement in infants12345

    PubMed Central

    Kong, Kai Ling; Feda, Denise M; Eiden, Rina D; Epstein, Leonard H

    2015-01-01

    Background: Rapid weight gain in infancy is associated with a higher risk of obesity in children and adults. A high relative reinforcing value of food is cross-sectionally related to obesity; lean children find nonfood alternatives more reinforcing than do overweight/obese children. However, to our knowledge, there is no research on how and when food reinforcement develops. Objective: This study was designed to assess whether the reinforcing value of food and nonfood alternatives could be tested in 9- to 18-mo-old infants and whether the reinforcing value of food and nonfood alternatives is differentially related to infant weight status. Design: Reinforcing values were assessed by using absolute progressive ratio schedules of reinforcement, with presentation of food and nonfood alternatives counterbalanced in 2 separate studies. Two nonfood reinforcers [Baby Einstein–Baby MacDonald shows (study 1, n = 27) or bubbles (study 2, n = 30)] were tested against the baby’s favorite food. Food reinforcing ratio (FRR) was quantified by measuring the reinforcing value of food (Food Pmax) in proportion to the total reinforcing value of food and a nonfood alternative (DVD Pmax or BUB Pmax). Results: Greater weight-for-length z score was associated with a greater FRR of a favorite food in study 1 (FRR-DVD) (r = 0.60, P < 0.001) and FRR of a favorite food in study 2 (FRR-BUB) (r = 0.49, P = 0.006), primarily because of the strong association between greater weight-for-length z score and lower DVD Pmax (r = −0.71, P < 0.0001) and BUB Pmax (r = −0.53, P = 0.003). Infant monthly weight gain was positively associated with FRR-DVD (r = 0.57, P = 0.009) and FRR-BUB (r = 0.37, P = 0.047). Conclusions: Our newly developed paradigm, which tested 2 different nonfood alternatives, demonstrated that lean infants find nonfood alternatives more reinforcing than do overweight/obese infants. This observation suggests that strengthening the alternative reinforcers may have a protective

  17. Structural and seismic analyses of waste facility reinforced concrete storage vaults

    SciTech Connect

    Wang, C.Y.

    1995-07-01

    Facility 317 of Argonne National Laboratory consists of several reinforced concrete waste storage vaults designed and constructed in the late 1940`s through the early 1960`s. In this paper, structural analyses of these concrete vaults subjected to various natural hazards are described, emphasizing the northwest shallow vault. The natural phenomenon hazards considered include both earthquakes and tornados. Because these vaults are deeply embedded in the soil, the SASSI (System Analysis of Soil-Structure Interaction) code was utilized for the seismic calculations. The ultimate strength method was used to analyze the reinforced concrete structures. In all studies, moment and shear strengths at critical locations of the storage vaults were evaluated. Results of the structural analyses show that almost all the waste storage vaults meet the code requirements according to ACI 349--85. These vaults also satisfy the performance goal such that confinement of hazardous materials is maintained and functioning of the facility is not interrupted.

  18. Hydrologic and Hydraulic effects of Riparian Root Networks on Streambank Stability: Is Mechanical Root-Reinforcement the Whole Story?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian vegetation has a number of effects on the mechanisms by which streambanks fail, some positive and some negative. Previous research has shown that the effect of mechanical root-reinforcement on soil stability can be considerable, and can be successfully quantified and included in streambank ...

  19. Soil Evaporation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil evaporation can significantly influence energy flux partitioning of partially vegetated surfaces, ultimately affecting plant transpiration. While important, quantification of soil evaporation, separately from canopy transpiration, is challenging. Techniques for measuring soil evaporation exis...

  20. Editorial "The Interdisciplinary Nature of SOIL"

    NASA Astrophysics Data System (ADS)

    Brevik, E. C.; Cerdá, A.; Mataix-Solera, J.; Pereg, L.; Quinton, J. N.; Six, J.; Van Oost, K.

    2014-09-01

    The holistic study of soils requires an interdisciplinary approach involving biologists, chemists, geologists, and physicists amongst others, something that has been true from the earliest days of the field. This approach has been strengthened and reinforced as current research continues to use experts trained in both soil science and related fields and by the wide array of issues impacting the world's biosphere that require an in-depth understanding of soils. Of fundamental importance amongst these issues are biodiversity, biofuels/energy security, climate change, ecosystem services, food security, human health, land degradation, and water security, each representing a critical challenge for research. In order to establish a benchmark for the type of research we seek to highlight in each issue of SOIL, here in this editorial, we outline the interdisciplinary nature of soil science research that we are seeking for in SOIL, with a focus on the myriad ways soil science can be used to expand investigation into a more holistic and therefore richer approach to soil research. In addition, we provide a selection of invited review papers in the first issue of SOIL that address the study of soils and the ways in which soil investigations are essential to other related fields. We hope that both this editorial and the first issue will serve as examples of the kinds of topics we would like to see published in SOIL and will stimulate excitement among our readers and authors to participate in this new venture.

  1. Systematic reinforcement: academic performance of underachieving students.

    PubMed

    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

  2. Food Reinforcement and Eating: A Multilevel Analysis

    PubMed Central

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

    2008-01-01

    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 provide a framework for examining factors that may influence eating and are outside of those that may regulate energy homeostasis. Methods to measure food reinforcement are reviewed, along with factors that influence the reinforcing value of eating. Contributions of neuroscience and genetics to the study of food reinforcement are illustrated by using the example of dopamine. Implications of food reinforcement for obesity and positive energy balance are explored, with suggestions for novel approaches to obesity treatment based on the synthesis of behavioral and pharmacological approaches to food reinforcement. PMID:17723034

  3. [Discussion on twirling reinforcing-reducing method].

    PubMed

    Shen, Te-Li

    2014-01-01

    The essence of twirling reinforcing-reducing method is discussed to provide theoretical guidance for clinical application of reinforcing-reducing method. Through retrospection on historical literature of twirling reinforcing-reducing method, records and explanatory notes are thoroughly explored. Several existing opinions are analyzed and explained for instance twirling method has connection with circulation direction of channels; twirling method is subdivided into right and left, male and female, hand and foot; twriling method is related to quantity of stimulus and operation time; twriling method belongs to spiral motion and so on. As a result, it is found that the key of twirling reinforcing-reducing method is the posture of needle-holding hand that defines three-dimensional motion. If twirling method is subdivided into right and left, male and female, hand and foot and so on, steric effects of lifting-thrusting movement that come along with twirling method could be ignored at the same time. It is that the essence of twirling reinforcing-reducing method is close to the principle of lifting-thrusting reinforcing-reducing method, enriching effect with slow insertion and fast withdrawal of needle while reducing effect with fast insertion and slow withdrawal, which is recorded in Miraculous Pivot: Nine needle and Twelve Yuan. With this principle as guide, manipulation could be avoided to become a mere formality and illusory metaphysics during clinical application of twirling reinforcing-reducing method. PMID:24673057

  4. Stress and strength analysis of fiber reinforced plastic pipe tees with reinforcement

    SciTech Connect

    Wei, Z.; Widera, G.E.O.; Xue, M.

    1996-12-01

    In this paper, a stress and strength analysis of fiber reinforced plastic (FRP) pipe tees with reinforcement by use of 3-D finite element method is presented. Wilson`s incompatible elements and the 16-node 3-D element with relative degrees of freedom have been employed to carry out the analysis. The reliability of the program is also investigated. Two reinforcing methods, pad and compact reinforcement, are investigated. The fact that the properties and principal directions of the materials of the two intersecting pipes and the reinforcement are different has been taken into account in the analysis. The continuity of stress and strain fields at the intersecting surface of two different materials is considered in the post processing of the FEM results. The results show that the stress concentration in a FRP pipe intersection without reinforcement (r/R = 0.4--0.7) is significant. A reasonable design can be obtained by considering both stress fields and the orthotropic strength parameters of the materials. The in-plane shear stress may be the controlling factor because of the relatively low shear strength of most composites. Use of either reinforcing method does not change the location of the maximum tensile stress and the maximum shear stress, and both alleviate the stress concentration at the intersection. It is shown that the compact reinforcing method is more effective than the pad one. The larger the reinforcing area of the compact reinforcing method, the smaller the stress concentration factor, but the lower the rate of reduction.

  5. Magnet retained lip prosthesis in a geriatric patient

    PubMed Central

    Rao, Srinivasa B; Gurram, Sunil Kumar; Mishra, Sunil Kumar; Chowdhary, Ramesh

    2015-01-01

    Surgical resection of lips is a relatively rare procedure. A defective lip may cause the patient to feel socially vulnerable as well as functionally handicapped and the defect will influence the patient's self-esteem and body image. Patients with labial defects also experience speech problems along with drying and crusting of the tissues in the area of defect. The lip and cheek provide a valve mechanism for speech. Rehabilitation of patients with this type of surgery creates numerous challenges for both the surgical and the maxillofacial prosthetic teams. The goals of prosthetic treatment include regaining favorable speech and restoration of esthetics. This case report presents a 65-year-old woman who was referred for restoration of her lost lip. This case paper describes a quick and simple method of positioning magnets with lip prosthesis attached to maxillary denture and thus esthetics and speech of the patient is restored. Use of retention magnets simplify the clinical and laboratory phase retains the denture and makes it stable and comfortable for the patient. The advent of magnets has enhanced the dental practitioner's capabilities with a remarkably improved potential for increasing prosthesis stability and preserving tissue. PMID:26929510

  6. Cruciate retaining and cruciate substituting ultra-congruent insert

    PubMed Central

    Deledda, Davide; Rosso, Federica; Ratto, Nicola; Bruzzone, Matteo; Bonasia, Davide Edoardo; Rossi, Roberto

    2016-01-01

    The posterior cruciate ligament (PCL) conservation and the polyethylene insert constraint in total knee arthroplasty (TKA) are still debated. The PCL is one of the primary stabilizers of the joint, but cruciate retaining (CR) implants have the disadvantage of a difficult balancing of the PCL. Postero-stabilized (PS) implants were introduced to reduce this problem. However, also the PS implants have some disadvantages, due to the cam-mechanism, such as high risk of cam-mechanism polyethylene wear. To minimize the polyethylene wear of the cam-mechanism and the bone sacrifice due to the intercondylar box, different types of inserts were developed, trying to increase the implant conformity and to reduce stresses on the bone-implant interface. In this scenario ultra-congruent (UC) inserts were developed. Those inserts are characterized by a high anterior wall and a deep-dished plate. This conformation should guarantee a good stability without the posterior cam. Few studies on both kinematic and clinical outcomes of UC inserts are available. Clinical and radiological outcomes, as well as kinematic data are similar between UC mobile bearing (MB) and standard PS MB inserts at short to mid-term follow-up. In this manuscript biomechanics and clinical outcomes of UC inserts will be described, and they will be compared to standard PS or CR inserts. PMID:26855938

  7. Retained energy-based coding for EEG signals.

    PubMed

    Bazán-Prieto, Carlos; Blanco-Velasco, Manuel; Cárdenas-Barrera, Julián; Cruz-Roldán, Fernando

    2012-09-01

    The recent use of long-term records in electroencephalography is becoming more frequent due to its diagnostic potential and the growth of novel signal processing methods that deal with these types of recordings. In these cases, the considerable volume of data to be managed makes compression necessary to reduce the bit rate for transmission and storage applications. In this paper, a new compression algorithm specifically designed to encode electroencephalographic (EEG) signals is proposed. Cosine modulated filter banks are used to decompose the EEG signal into a set of subbands well adapted to the frequency bands characteristic of the EEG. Given that no regular pattern may be easily extracted from the signal in time domain, a thresholding-based method is applied for quantizing samples. The method of retained energy is designed for efficiently computing the threshold in the decomposition domain which, at the same time, allows the quality of the reconstructed EEG to be controlled. The experiments are conducted over a large set of signals taken from two public databases available at Physionet and the results show that the compression scheme yields better compression than other reported methods. PMID:22056794

  8. Intravitreal Phacoemulsification Using Torsional Handpiece for Retained Lens Fragments

    PubMed Central

    Kumar, Vinod; Takkar, Brijesh

    2016-01-01

    Purpose: To evaluate the results of intravitreal phacoemulsification with torsional hand piece in eyes with posteriorly dislocated lens fragments. Methods: In this prospective, interventional case series, 15 eyes with retained lens fragments following phacoemulsification were included. All patients underwent standard three-port pars plana vitrectomy and intravitreal phacoemulsification using sleeveless, torsional hand piece (OZiL™, Alcon's Infiniti Vision System). Patients were followed up for a minimum of six months to evaluate the visual outcomes and complications. Results: The preoperative best-corrected visual acuity (BCVA) ranged from light perception to 0.3. No complications such as thermal burns of the scleral wound, retinal damage due to flying lens fragments, or difficult lens aspiration occurred during intravitreal phacoemulsification. Mean post-operative BCVA at the final follow-up was 0.5. Two eyes developed cystoid macular edema, which was managed medically. No retinal detachment was noted. Conclusion: Intravitreal phacoemulsification using torsional hand piece is a safe and effective alternative to conventional longitudinal phacofragmentation.

  9. The Role of Organizational Culture in Retaining Nursing Workforce

    PubMed Central

    Banaszak-Holl, Jane; Castle, Nicholas G.; Lin, Michael K.; Shrivastwa, Nijika; Spreitzer, Gretchen

    2015-01-01

    Purpose of the Study: We examined how organizational culture in nursing homes affects staff turnover, because culture is a first step to creating satisfactory work environments. Design and Methods: Nursing home administrators were asked in 2009 to report on facility culture and staff turnover. We received responses from 419 of 1,056 administrators contacted. Respondents reported the strength of cultural values using scales from a Competing Values Framework and percent of staff leaving annually for Registered Nurse (RN), Licensed Practice Nurse (LPN), and nursing aide (NA) staff. We estimated negative binomial models predicting turnover.  Results: Turnover rates are lower than found in past but remain significantly higher among NAs than among RNs or LPNs. Facilities with stronger market values had increased turnover among RNs and LPNs, and among NAs when turnover was adjusted for facilities with few staff. Facilities emphasizing hierarchical internal processes had lower RN turnover. Group and developmental values focusing on staff and innovation only lowered LPN turnover. Finally, effects on NA turnover become insignificant when turnover was adjusted if voluntary turnover was reported. Implications: Organizational culture had differential effects on the turnover of RN, LPN, and NA staff that should be addressed in developing culture-change strategies. More flexible organizational culture values were important for LPN staff only, whereas unexpectedly, greater emphasis on rigid internal rules helped facilities retain RNs. Facilities with a stronger focus on customer needs had higher turnover among all staff. PMID:24218146

  10. Recruiting and Retaining Arab Muslim Mothers and Children for Research

    PubMed Central

    Aroian, Karen J.; Katz, Anne; Kulwicki, Anahid

    2006-01-01

    Purpose To describe successful and not-so-successful strategies for recruiting and retaining Arab Muslim immigrant women and their adolescent children for research. Design and Methods A longitudinal study of mother-child adjustment of Arab immigrants to the US is used for illustration. A panel of experts was assembled and provided culturally specific advice about gatekeepers, advertising, data collectors, data collection, and how to track and encourage participation at subsequent time points in the study. Findings Most of the strategies recommended by the panel were overwhelmingly positive, including advice about data collectors, how to collect data, financial incentives, avoiding offending families, and personal contacts. Hiring data collectors who were able to establish personal and culturally appropriate relationships with study participants was the single most successful recruitment and retention strategy. Advice from cultural experts about which gatekeepers to engage and how to advertise for study participants was not productive. Conclusions Researchers should not only assemble a panel of cultural experts to provide advice about group specific strategies to build trust and maintain cultural sensitivity, but also to budget generously for time for data collectors to build and maintain rapport with study populations who, like Arab immigrant women, highly value personal relationships. PMID:17044343

  11. Automated identification of retained surgical items in radiological images

    NASA Astrophysics Data System (ADS)

    Agam, Gady; Gan, Lin; Moric, Mario; Gluncic, Vicko

    2015-03-01

    Retained surgical items (RSIs) in patients is a major operating room (OR) patient safety concern. An RSI is any surgical tool, sponge, needle or other item inadvertently left in a patients body during the course of surgery. If left undetected, RSIs may lead to serious negative health consequences such as sepsis, internal bleeding, and even death. To help physicians efficiently and effectively detect RSIs, we are developing computer-aided detection (CADe) software for X-ray (XR) image analysis, utilizing large amounts of currently available image data to produce a clinically effective RSI detection system. Physician analysis of XRs for the purpose of RSI detection is a relatively lengthy process that may take up to 45 minutes to complete. It is also error prone due to the relatively low acuity of the human eye for RSIs in XR images. The system we are developing is based on computer vision and machine learning algorithms. We address the problem of low incidence by proposing synthesis algorithms. The CADe software we are developing may be integrated into a picture archiving and communication system (PACS), be implemented as a stand-alone software application, or be integrated into portable XR machine software through application programming interfaces. Preliminary experimental results on actual XR images demonstrate the effectiveness of the proposed approach.

  12. Leading a multigenerational workforce: strategies for attracting and retaining millennials.

    PubMed

    Cahill, Terrence F; Sedrak, Mona

    2012-01-01

    Over the past several years, leaders in healthcare have noticed an increase in generational tension among employees, most often focused on the attitudes and behaviors of the arriving millennials (generation Y). While these employee relations issues were a nuisance, they rarely rose to the level of a priority demanding leadership intervention. Some leaders, in fact, hoped that the issues would resolve themselves as these young employees settled in and learned that they had to demonstrate new behaviors to be successful in the workplace. Most organizations adopted this wait-and-see attitude. Not so today. As the boomer generation has begun its exodus from the workplace, organizations are increasingly looking at the millennials as not a problem but a solution to the workplace manpower transition that is under way. Our problem is that we don't yet know how best to lead such a diverse, multigenerational workforce. This article examines the generational topic and provides advice concerning a variety of changes that leaders may implement to advance their organization's ability to attract and to retain the millennials. PMID:23050333

  13. Bacterial RNA polymerase can retain σ70 throughout transcription.

    PubMed

    Harden, Timothy T; Wells, Christopher D; Friedman, Larry J; Landick, Robert; Hochschild, Ann; Kondev, Jane; Gelles, Jeff

    2016-01-19

    Production of a messenger RNA proceeds through sequential stages of transcription initiation and transcript elongation and termination. During each of these stages, RNA polymerase (RNAP) function is regulated by RNAP-associated protein factors. In bacteria, RNAP-associated σ factors are strictly required for promoter recognition and have historically been regarded as dedicated initiation factors. However, the primary σ factor in Escherichia coli, σ(70), can remain associated with RNAP during the transition from initiation to elongation, influencing events that occur after initiation. Quantitative studies on the extent of σ(70) retention have been limited to complexes halted during early elongation. Here, we used multiwavelength single-molecule fluorescence-colocalization microscopy to observe the σ(70)-RNAP complex during initiation from the λ PR' promoter and throughout the elongation of a long (>2,000-nt) transcript. Our results provide direct measurements of the fraction of actively transcribing complexes with bound σ(70) and the kinetics of σ(70) release from actively transcribing complexes. σ(70) release from mature elongation complexes was slow (0.0038 s(-1)); a substantial subpopulation of elongation complexes retained σ(70) throughout transcript elongation, and this fraction depended on the sequence of the initially transcribed region. We also show that elongation complexes containing σ(70) manifest enhanced recognition of a promoter-like pause element positioned hundreds of nucleotides downstream of the promoter. Together, the results provide a quantitative framework for understanding the postinitiation roles of σ(70) during transcription. PMID:26733675

  14. Who is Retained in First Grade? A Psychosocial Perspective

    PubMed Central

    Willson, Victor L.; Hughes, Jan N.

    2008-01-01

    A sample of 784 children with below-median literacy performance in kindergarten or at the beginning of grade 1 was assessed in 5 areas of psychological and social variables: academic competence, sociodemographic characteristics, social/emotional/behavioral characteristics, school context, and home environment. We examined the contribution of academic competence to retention first, and then evaluated contributions of each of the other areas beyond academic competence. The 165 students retained in first grade were found to differ from promoted students on reading and mathematics achievement test scores, teacher-rated engagement and achievement, and intelligence as individual predictors of academic competence, but with direct effects only for reading and teacher-rated achievement when entered as a set of predictors. None additional variables had zero-order significant correlations with retention status. Using hierarchical logistic regression, beyond the effects of academic competence variables we found that only being underage for grade and the home environmental variables of positive parental perceptions of their child’s school, sense of shared responsibility for education with the school, and parent communication with the school contributed significantly to retention. Implications for educational policy and intervention are discussed. PMID:19756171

  15. Improving wheat to remove coeliac epitopes but retain functionality

    PubMed Central

    Shewry, Peter R.; Tatham, Arthur S.

    2016-01-01

    Coeliac disease is an intolerance triggered by the ingestion of wheat gluten proteins. It is of increasing concern to consumers and health professionals as its incidence appears to be increasing. The amino acid sequences in gluten proteins that are responsible for triggering responses in sensitive individuals have been identified showing that they vary in distribution among and between different groups of gluten proteins. Conventional breeding may therefore be used to select for gluten protein fractions with lower contents of coeliac epitopes. Molecular breeding approaches can also be used to specifically down-regulate coeliac-toxic proteins or mutate coeliac epitopes within individual proteins. A combination of these approaches may therefore be used to develop a “coeliac-safe” wheat. However, this remains a formidable challenge due to the complex multigenic control of gluten protein composition. Furthermore, any modified wheats must retain acceptable properties for making bread and other processed foods. Not surprisingly, such coeliac-safe wheats have not yet been developed despite over a decade of research. PMID:26937068

  16. DISTRIBUTED AND ACCUMULATED REINFORCEMENT ARRANGEMENTS: EVALUATIONS OF EFFICACY AND PREFERENCE

    PubMed Central

    DELEON, ISER G.; CHASE, JULIE A.; FRANK-CRAWFORD, MICHELLE A.; CARREAU-WEBSTER, ABBEY B.; TRIGGS, MANDY M.; BULLOCK, CHRISTOPHER E.; JENNETT, HEATHER K.

    2015-01-01

    We assessed the efficacy of, and preference for, accumulated access to reinforcers, which allows uninterrupted engagement with the reinforcers but imposes an inherent delay required to first complete the task. Experiment 1 compared rates of task completion in 4 individuals who had been diagnosed with intellectual disabilities when reinforcement was distributed (i.e., 30-s access to the reinforcer delivered immediately after each response) and accumulated (i.e., 5-min access to the reinforcer after completion of multiple consecutive responses). Accumulated reinforcement produced response rates that equaled or exceeded rates during distributed reinforcement for 3 participants. Experiment 2 used a concurrent-chains schedule to examine preferences for each arrangement. All participants preferred delayed, accumulated access when the reinforcer was an activity. Three participants also preferred accumulated access to edible reinforcers. The collective results suggest that, despite the inherent delay, accumulated reinforcement is just as effective and is often preferred by learners over distributed reinforcement. PMID:24782203

  17. Distributed and accumulated reinforcement arrangements: evaluations of efficacy and preference.

    PubMed

    DeLeon, Iser G; Chase, Julie A; Frank-Crawford, Michelle A; Carreau-Webster, Abbey B; Triggs, Mandy M; Bullock, Christopher E; Jennett, Heather K

    2014-01-01

    We assessed the efficacy of, and preference for, accumulated access to reinforcers, which allows uninterrupted engagement with the reinforcers but imposes an inherent delay required to first complete the task. Experiment 1 compared rates of task completion in 4 individuals who had been diagnosed with intellectual disabilities when reinforcement was distributed (i.e., 30-s access to the reinforcer delivered immediately after each response) and accumulated (i.e., 5-min access to the reinforcer after completion of multiple consecutive responses). Accumulated reinforcement produced response rates that equaled or exceeded rates during distributed reinforcement for 3 participants. Experiment 2 used a concurrent-chains schedule to examine preferences for each arrangement. All participants preferred delayed, accumulated access when the reinforcer was an activity. Three participants also preferred accumulated access to edible reinforcers. The collective results suggest that, despite the inherent delay, accumulated reinforcement is just as effective and is often preferred by learners over distributed reinforcement. PMID:24782203

  18. The interdisciplinary nature of SOIL

    NASA Astrophysics Data System (ADS)

    Brevik, E. C.; Cerdà, A.; Mataix-Solera, J.; Pereg, L.; Quinton, J. N.; Six, J.; Van Oost, K.

    2015-01-01

    The holistic study of soils requires an interdisciplinary approach involving biologists, chemists, geologists, and physicists, amongst others, something that has been true from the earliest days of the field. In more recent years this list has grown to include anthropologists, economists, engineers, medical professionals, military professionals, sociologists, and even artists. This approach has been strengthened and reinforced as current research continues to use experts trained in both soil science and related fields and by the wide array of issues impacting the world that require an in-depth understanding of soils. Of fundamental importance amongst these issues are biodiversity, biofuels/energy security, climate change, ecosystem services, food security, human health, land degradation, and water security, each representing a critical challenge for research. In order to establish a benchmark for the type of research that we seek to publish in each issue of SOIL, we have outlined the interdisciplinary nature of soil science research we are looking for. This includes a focus on the myriad ways soil science can be used to expand investigation into a more holistic and therefore richer approach to soil research. In addition, a selection of invited review papers are published in this first issue of SOIL that address the study of soils and the ways in which soil investigations are essential to other related fields. We hope that both this editorial and the papers in the first issue will serve as examples of the kinds of topics we would like to see published in SOIL and will stimulate excitement among our readers and authors to participate in this new venture.

  19. Fiber reinforced composite resin systems.

    PubMed

    Giordano, R

    2000-01-01

    The Targis/Vectris and Sculpture/FibreKor systems were devised to create a translucent maximally reinforced resin framework for fabrication of crowns, bridges, inlays, and onlays. These materials are esthetic, have translucency similar to castable glass-ceramics such as OPC and Empress, and have fits that are reported to be acceptable in clinical and laboratory trials. These restorations rely on proper bonding to the remaining tooth structure; therefore, careful attention to detail must be paid to this part of the procedure. Cementation procedures should involve silane treatment of the cleaned abraded internal restoration surface, application of bonding agent to the restoration as well as the etched/primed tooth, and finally use of a composite resin. Each manufacturer has a recommended system which has been tested for success with its resin system. These fiber reinforced resins are somewhat different than classical composites, so not all cementation systems will necessarily work with them. Polishing of the restoration can be accomplished using diamond or alumina impregnated rubber wheels followed by diamond paste. The glass fibers can pose a health risk. They are small enough to be inhaled and deposited in the lungs, resulting in a silicosis-type problem. Therefore, if fibers are exposed and ground on, it is extremely important to wear a mask. Also, the fibers can be a skin irritant, so gloves also should be worn. If the fibers become exposed intraorally, they can cause gingival inflammation and may attract plaque. The fibers should be covered with additional composite resin. If this cannot be accomplished, the restoration should be replaced. The bulk of these restorations are formed using a particulate filled resin, similar in structure to conventional composite resins. Therefore, concerns as to wear resistance, color stability, excessive expansion/contraction, and sensitivity remain until these materials are proven in long-term clinical trials. They do hold the

  20. Ensemble algorithms in reinforcement learning.

    PubMed

    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