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Recently, teacher candidate performance assessments have been implemented across the nation for multiple purposes, including supporting teacher candidate learning, assessing teacher quality, informing programmatic improvement, and addressing state accountability needs. However, state policies surrounding these assessments risk limiting their potential to support candidate learning. In this article, we describe the local policy context that supported the development of a statewide performance assessment, the New Hampshire Teacher Candidate Assessment of Performance (NH TCAP). We present a mixed methods study that analyzed teacher candidates'/graduates' perspectives on what the NH TCAP measures and its value as a tool for learning. Findings suggest that those who view the NH TCAP as a tool for learning also view it as a useful measure of their teaching practice but that other key characteristics of effective teachers and teaching are not assessed on the performance assessment. We raise questions about the possibilities and limits of teacher candidate performance assessments and offer implications for their use as tools for learning., Introduction Federal and state policies demand a growing list of accountability measures of educator preparation programs (Cochran-Smith, 2001). As part of these initiatives, policy makers, accrediting bodies, and teacher educators [...]

Abstract: Research has demonstrated that students do not intuitively 'pick up' on how to accomplish various speech tasks (e.g., requesting, offering, etc.) in a pragmatically appropriate way (Kasper & Rose, [...]

Background: Mediastinal mass resection and thymectomy are complex and related operations that are core aspects of competency for a general thoracic surgeon. This study aimed to design a combined competency-based [...]

Background: There is a notably steep learning curve to arthroscopy. In a time-constrained residency, simulation provides an additional medium to practice. However, as residents progress through a competency-based program, it [...]

Background: Virtual reality surgical simulators have facilitated surgical education by providing safe training environments. Electroencephalography (EEG) has been used to assess neural activity during surgical performance. Machine learning (ML) has [...]

'The Widget Effect,' a widely read 2009 report from The New Teacher Project, surveyed the teacher evaluation systems in 14 large American school districts and concluded that status quo systems [...]

A method of measurement selection is introduced that relies on parameter signatures to assess the identifiability of dynamic model parameters by different outputs. A parameter signature is a region in the time-scale plane wherein the sensitivity of the output with respect to one model parameter is much larger than the rest of the output sensitivities. Since a parameter signature can be extracted when the corresponding output sensitivity is independent of the others, the ability to extract parameter signatures is indicative of parameter identifiability by the output and used here for output/measurement selection. The purpose of this paper is to introduce a strategy for measurement selection by parameter signatures and to demonstrate its applicability to the transient decks of turbojet engines. The validity of the selected outputs in providing observability to all the engine model parameters is independently verified by successful estimation of parameters by nonlinear least-squares estimation. [DOI: 10.1115/1.4001808] Keywords: measurement selection, system identification, fault diagnosis, wavelet transforms

Williams, JD, Abt, G, and Kilding, AE. Ball-sport endurance and sprint test ([BEAST.sub.90]): validity and reliability of a 90-minute soccer performance test. J Strength Cond Res 24(12): 3209-3218, 2010--The aim of this study was to determine the validity and reliability of a 90-minute soccer performance test: Ballsport Endurance and Sprint Test ([BEAST.sub.90]). Fifteen healthy male amateur soccer players participated and attended 5 testing sessions over a 10-day period to perform physiologic and soccer-specific assessments. This included familiarization sessions and 2 full trials of the [BEAST.sub.90], separated by 7 days. The total 90-minute distance, mean percent peak heart rate ([HR.sub.peak]), and estimated percent peak oxygen uptake of the [BEAST.sub.90] were 8,097 [+ or -] 458 m, 85 [+ or -] 5% and 82 [+ or -] 14%, respectively. Measures obtained from trial 1 and trial 2 were not significantly different (p > 0.05). Reliability of measures over 90 minutes ranged from 0.9-25.5% (% typical error). The [BEAST.sub.90] protocol replicated soccer match play in terms of time, movement patterns, physical demands (volume and intensity), distances, and mean and [HR.sub.peak] values, as well as having an aerobic Ioad similar to that observed during a soccer match. Reproducibility of key physical measures during the [BEAST.sub.90] were mostly high, suggesting good reliability. The [BEAST.sub.90] could be used in studies that wish to determine the effects of training or nutritional interventions on prolonged intermittent physical performance. KEY WORDS football, soccer protocol, intermittent

Hydrazine monopropellant is often used with a spontaneous catalyst a high-performance aircraft emergency power unit (EPU) and in aerospace propulsion; however, it is toxic and requires special handling. A hydrogen peroxide ([H.sub.2][O.sub.2])-based gas generator, which is suitable for a new family of environmentally friendly monopropellants and is a substitute for toxic hydrazine in EPUs, is introduced in this study. A Mn[O.sub.2]/[Al.sub.2][O.sub.3] catalyst for [H.sub.2][O.sub.2] decomposition, superior to silver catalysts at normal starting and reactivity capabilities, was selected and developed. The performance tests of coupling the gas generator with a turbocharger showed acceptable results for an aircraft EPU with decomposition above 90%, 37 kW maximum turbine output power, and a maximum starting delay of 1.2 s during normal starting operation. The gas generator also demonstrated satisfactory performance during repeated pulse operation at a pulse duration of 3 s and 60 s under various output conditions. [DOI: 10.1115/1.4000896] Keywords: aircraft, catalyst, EPU, hydrogen peroxide, [H.sub.2][O.sub.2], gas generator, Mn[O.sub.2]/[Al.sub.2][O.sub.3], catalyst, turbocharger

A hyperspectral Shack--Hartmann test bed has been developed to characterize the performance of miniature optics across a wide spectral range, a necessary first step in developing broadband achromatized all-polymer endomicroscopes. The Shack--Hartmann test bed was used to measure the chromatic focal shift (CFS) of a glass singlet lens and a glass achromatic lens, i.e., lenses representing the extrema of CFS magnitude in polymer elements to be found in endomicroscope systems. The lenses were tested from 500 to 700 nm in 5 and 10 nm steps, respectively. In both cases, we found close agreement between test results obtained from a ZEMAX model of the test bed and test lens and those obtained by experiment (maximum error of 12 [micro]m for the singlet lens and 5 [micro]m for the achromatic triplet lens). Future applications of the hyperspectral Shack-Hartmann test include measurements of aberrations as a function of wavelength, characterization of manufactured plastic endomicroscope elements and systems, and reverse optimization. OCIS codes: 220.4840, 220.3620, 220.1000.

Core melt solidification phenomena in the lower plenum of pressurized reactor vessel during external reactor vessel cooling is investigated in late in-vessel phase experiment tests under different external cooling conditions and melt pouring positions. The melt solidification behavior, which has not yet been given sufficient attention, is an important issue since it influences not only the transient but also the steady state of melt pool thermal hydraulics. A noneutectic melt (80 mol % KN[O.sub.3]-20 mol % NAN[O.sub.3]) was used to simulate the core melt. It has been found out that when the vessel is cooled with water during the whole test period (water cooling), the cooling is more effective than the case that the vessel lower head is first cooled with air and flooded by water (air/water cooling). Water cooling at the beginning leads to faster buildup of crust layer on the vessel inner wall and lower crust thermal conductivity compared with air/water cooling. In comparison with the air/water cooling, the water cooling also achieves shorter time period of crust growth. During the solidification period in all tests, the constitutional supercooling condition is fulfilled. Pouring position near the vessel wall results in considerable asymmetry, in the heat flux distribution through the vessel wall. [DOI: 10.1115/1.400108l] Keywords: core melt, in-vessel, crust, solidification, lower head, heat flux, IVR, PWR, PRV

Prototype fast breeder reactor is U-Pu[O.sub.2] fueled sodium cooled pool type fast reactor and it is currently under construction at Kalpakkam, India. Prototype fast breeder reactor is equipped with two independent fast acting and diverse shutdown systems. A shutdown system comprises of sensors, logic circuits, drive mechanisms, and neutron absorbing rods. The two shutdown systems of prototype fast breeder reactor are capable of bringing down the reactor to cold shutdown state independent of the other. The absorber rods of the second shutdown system of prototype fast breeder reactor are called as diverse safety rods (DSRs) and their drive mechanisms are called as diverse safety rod drive mechanisms (DSRDMs). DSRs are normally parked above active core by DSRDMs. On receiving scram signal, the electromagnet of DSRDM is de-energized and it facilitates fast shutdown of the reactor by dropping the DSR into the active core. For the development of prototypes of DSR and DSRDM, three phases of testing, namely, individual component testing, integrated functional testing in room temperature, and endurance testing at high temperature sodium, were done. The electromagnet of DSRDM has been separately tested at room temperature, in furnace, and in sodium. Specimens simulating the contact conditions between electromagnet and armature of DSR have been tested to rule out self-welding possibility. The prototype of DSR has been tested in flowing water to determine the pressure drop and drop time. The functional testing of the integrated prototype DSRDM and DSR in aligned and misaligned conditions in air/water has been completed. The performance testing of the integrated system in sodium has been done in three campaigns. During the third campaign of sodium testing, the performance of the system has been verified with 30 mm misalignment at various temperatures. The third campaign has qualified the system for 10 years of operation in reactor. This paper presents design, development, testing, and qualification of the prototype DSR and DSRDM. Salient design specifications for both DSRDM and DSR are listed initially. The conceptual and detailed design features are explained with the help of figures. Details on material of construction are given at appropriate places. Test plans and criteria for endurance testing in sodium for qualification of DSRDM and DSR for operation in reactor are briefed. Brief explanation of test setups and typical test results are also given. [DOI: 10.1115/1.4001059] Keywords: absorber rod, drive mechanism, fast breeder reactor, scram

The very long absence of floods with a return period of more than about 100 years in the Vltava fiver basin dulled the vigilance of the state administration and self-government bodies. Flood safety measures were mostly related to once-in-a-hundred- years floods. When planning the engineering works before major repairs to the medieval Stone Bridge in Pisek in the 1990s, an unpleasant but justified question was raised--what would happen to the Stone Bridge if an extremely powerful 500-year return period flood were to occur? The following case study deals with this question and provides a definitive answer to it. Works were carried out on the Stone Bridge, which was just a few years later exposed to the catastrophic flood that occurred in Bohemia in 2002. DOI: 10.1061/(ASCE)CF.1943-5509.0000084 CE Database subject headings: Bridges; Floods; Rehabilitation; Historic sites; Europe. Author keywords: Bridge; Flood; Retrofitting.

We outline the development of a computational procedure for finite-element analysis of suction-caisson behavior, highlighting its unique features and capabilities. The procedure is based on a description of clayey soil as a two-phase medium: a water-filled porous solid. Nonlinear behavior of the solid phase is represented by means of a bounding-surface plasticity model. An algorithm is developed for frictional contact in terms of effective normal stress. Furthermore, a special remeshing scheme is introduced facilitating the simulation of the installation process, tracking the caisson penetration path and avoiding numerical complications in the vicinity of the caisson-soil interfaces. To illustrate the use of the proposed computational procedure and examine its validity, complete simulations of available laboratory tests on model suction caissons are conducted. Results are presented and discussed for test-bed preparation (consolidation) followed by caisson installation by self-weight and suction, setup (reconsolidation), and axial pullout. The overall agreement between computations and measurements is good. Possible improvements are identified and recommendations are made regarding future studies. DOI: 10.1061/(ASCE)GT.1943-5606.0000321 CE Database subject headings: Caissons; Porous media; Friction; Pullout; Finite element method; Numerical models. Author keywords: Caisson; Suction; Anchor; Offshore; Penetration; Porous medium; Porous media; Friction; Consolidation; Setup; Pullout; Axial capacity; Finite element.

This paper presents the results of a numerical investigation into the performance of geosynthetic-encased stone columns (GESCs) installed in soft ground for embankment construction. A three-dimensional finite-element model was employed to carry out a parametric study on a number of governing factors such as the consistency of soft ground, the geosynthetic encasement length and stiffness, the embankment fill height, and the area replacement ratio. The results indicate among other things that additional confinement provided by the geosynthetic encasement increases the stiffness of the stone column and reduces the degree of embankment load transferred to the soft ground, thereby decreasing the overall settlement. It is also shown that the geosynthetic encasement has a greater impact for cases with larger stone column spacing and/or weaker soil. Also revealed is that unlike isolated column loading conditions, full encasement may be necessary to ensure maximum settlement reduction when implementing GESCs under an embankment loading condition. Practical implications of the findings are discussed in detail. DOI: 10.1061/(ASCE)GT.1943-5606.0000316 CE Database subject headings: Geosynthetics; Stones; Columns; Soil consolidation; Soil stabilization; Finite element method; Embankments. Author keywords: Geosynthetic; Stone column; Consolidation; Ground improvement; Finite-element method.

This technical note presents the results of a study focused on the evaluation of laser beam divergence and its effect on the spot size of terrestrial laser scanners. For this purpose, experiments were accomplished using the Leica HDS3000 and HDS6000 laser scanners. Two methods for the evaluation of the spot size are compared: a direct method, based on the analysis of the capacity of the laser beam to go through small slots, and an analytical method that estimates the spot diameter based on the edge effect. Based on the performed experiments, the development of a conceptual model of the edge effect at sharp edges is described for each method and validated. The experiments proved that the methods are suitable to analyze the variation of the diameter of the spot as a function of the distance. The estimate of the spot size using slots of varying sizes is a direct and easy to use method, but the computation of the spot size using the sharp edge model is more stable in relation to the point density, and can be used to estimate the divergence of the laser beam and the expectable spot size before a survey is performed. DOI: 10.1061/(ASCE)SU.1943-5428.0000021 CE Database subject headings: Surveys; Digital techniques; Lasers. Author keywords: Terrestrial laser scanner; Surveying.

The water balances and the long-term performance of different landfill cover systems have been measured in situ in large-scale lysimeters on the landfill Hamburg-Georgswerder, Germany since 1988. The cover systems including different barrier components for water transport were constructed with state-of-the-art technology and have been excavated at several occasions especially to inspect the structure of the barriers. For the first time, the irreversible impact of crack formation in cohesive soil barriers and geosynthetic clay barriers due to desiccation, shrinkage, ion exchange, and plant root penetration has been observed and quantified in this study. After four years of good performance, these covers began to leak between 90 and 200 ram/year (average precipitation of 860 ram/year). The hydraulic conductivity of the cohesive soil barriers increased from 2 x [10.sup.-1] to 9 x [10.sup.-8] m/s, the daily peaks of the leakage through the geosynthetic clay barriers from initial values around 2 x [10.sup.-11] to 2 x [10.sup.-7] [m.sup.3]/([m.sup.2] s). The composite barriers with geomembranes above cohesive soil barriers performed very well, showing no leakage and only very little thermally induced water transport. A capillary barrier also performed well (average annual leakage of 18 mm/year). The data of the past 10 years prove that evapotranspiration can be increased significantly by planting bushes, which also limits the potential leakage through barrier layers. DOI: 10.1061/(ASCE)EE.1943-7870.0000200 CE Database subject headings: Barriers; Clay liners; Geomembranes; Landfills; Lysimeters; Reclamation; Remediation; Water balance; Germany. Author keywords: Barriers; Clay liners; Geomembranes; Landfills; Lysimeters; Reclamation; Remedial action; Water balance.

Understanding the complex mechanisms of stress transfer and strain accumulation in layers of track substructure under repeated wheel loading is essential to predict the desirable track maintenance cycle as well as the design of the new track. Various finite element and analytical techniques have been developed in the past to understand the behavior of composite track layers subjected to repeated wheel loads. The mechanical behavior of ballast is influenced by several factors, including the track confining pressure, type of aggregates, and the number of loading cycles. A field trial was conducted on an instrumented track at Bulli, New South Wales, Australia, with the specific aims of studying the benefits of a geocomposite installed at the ballast-capping interface, and to evaluate the performance of moderately graded recycled ballast in comparison to traditionally very uniform fresh ballast. It was found that recycled ballast can be effectively reused if reinforced with a geocomposite. It was also found that geocomposite can effectively reduce vertical and lateral strains of the ballast with obvious implications for improved track stability and reduced maintenance costs. DOI: 10.1061/(ASCE)GT.1943-5606.0000312 CE Database subject headings: Railroad tracks; Ballast; Cyclic loads; Deformation; Geosynthetics. Author keywords: Railroad tracks; Ballast; Cyclic loads; Deformation.

This paper presents a simplified direct displacement design (DDD) procedure which was used to design the shear walls for a six-story woodframe structure. The building was tested in the final phase of a Network for Earthquake Engineering Simulation (NEES) project. Specifically, NEESWood Capstone Building was designed to meet four performance expectations: damage limitation, life safety, far-field collapse prevention (CP), and near-fault CE The performance expectations are defined in terms of combinations of interstory drift limits and prescribed seismic hazard levels associated with predefined nonexceedance probabilities. To verify that design requirements were met, a series of nonlinear time-history analyses (NLTHAs) was performed using suits of both far-field and near-fault ground motion records. The distributions of interstory drifts obtained from the NLTHA confirm that the Capstone Building designed using DDD meets all four target performance expectations, thereby validating the DDD procedure. Additionally, collapse analysis in accordance with the recently proposed Applied Technology Council project 63 (ATC-63) methodology was performed. The results of incremental dynamic analyses confirmed that the Capstone Building designed using the DDD procedure has adequate capacity margin against collapse, as dictated by the ATC-63 methodology. DOI: 10.1061/(ASCE)ST.1943-541X.0000181 CE Database subject headings: Displacement; Wood structures; Structural design; Shear walls; Earthquake engineering; Seismic effects. Author keywords: Displacement-based design; Wood structures; Shear walls; Earthquake engineering; Seismic hazard; Structural engineering; Performance-based design.

The out-of-plane seismic performance of residential brick veneer walls built over wood-frame backup was evaluated as a function of construction detailing. Shake table tests were conducted on a full-scale brick veneer wall panel, with a window opening, representing the gable-end wall of a typical home structure; the structural performance of corrugated sheet metal veneer-to-wood tie connections was also characterized by separate laboratory testing. The wall panel test specimen was prepared following typical construction practice for brick veneer wall systems, in general conformance with current specified prescriptive design and construction requirements. The shake table tests captured the performance of the brick veneer wall system, including interaction and load-sharing between the brick veneer, corrugated sheet metal ties, and wood-frame backup. Detailed three-dimensional finite-element (FE) models were also developed representing the full-scale brick veneer wall panel specimen, including nonlinear inelastic properties for the tie connections. After calibration based on test results, the FE wall panel model effectively captured static and dynamic experimental brick veneer wall behavior at different response levels, up to and including tie damage and even instability/collapse of the wall panel. Parametric studies were then carried out using FE wall panel models to evaluate the effects of certain types and layouts of tie connections, as well as geometric variations in brick veneer wall construction. Overall seismic performance of brick veneer walls was closely related to the individual tie connection deformation limits, especially for damage in tension. The grid spacing of tie connections, as well as tie installation along the edges and in upper regions of the walls, controlled the ultimate behavior of the brick veneer wall panels. Design guides, codes, and current construction practices have been evaluated in light of the overall findings from these experimental and analytical studies. DOI: 10.1061/(ASCE)ST.1943-541X.0000169 CE Database subject headings: Bricks; Masonry; Veneers; Frames; Connections; Dynamic tests; Dynamic analysis; Seismic effects. Author keywords: Brick masonry veneer; Wood framing; Metal tie connections; Dynamic tests; Nonlinear dynamic analysis.

The seismic resistance of full-scale superassemblage of precast hollow core wall units is investigated. The superassemblage consists of six prestressed concrete 1.2 m wide hollow core units. Two load-bearing of the units are tied to the foundation via unbonded vertical tendons while the other four units primarily act as 'nonstructural' cladding. The longitudinal unbonded prestressing tendons consist of regular thread-bars with an in-series portion of those bars possessing a reduced diameter to act as 'fuses.' The multipanel wall system is tested under several different conditions: in-plane quasi-static reverse cyclic loading with different sizes of fuse bars and with and without rubber block spacers and sealant between units. No structural damage occurs up to the experimental [+ or -] 4% drift limit and only minor nonstructural distress is observed at 3% drift. The overall good performance of the multipanel wall system well satisfies the requirements of an emerging seismic damage avoidance design philosophy. DOI: 10.1061/(ASCE)ST.1943-541X.0000183 CE Database subject headings: Damage; Structural design; Prestressing; Tendons; Cladding; Precasting; Walls; Seismic effects. Author keywords: Fuse bars; Damage avoidance design; Unbonded prestressing tendons; Nonstructural cladding; Multipanel precast hollow core wall.

Ensuring sufficient water availability in hydrating concrete is a key to achieving quality curing that protects the fresh concrete in the short term and develops the potential properties of the mixture for long-term performance of concrete pavement. Excessive early-age evaporation from the concrete pavement surface can potentially result in plastic shrinkage cracking, high porosity, and low strength at the concrete surface leading to a variety of surface distresses. Application of liquid curing compounds on newly placed concrete pavement surfaces has been widely used to minimize evaporation. However, the availability of a test method to assess the efficacy of a curing compound relative to the actual environmental conditions encountered in the field is still lacking. Therefore, advancements are needed to further facilitate the evaluation of curing effectiveness (CE). This paper presents a laboratory-based procedure, which bridges laboratory measured parameters to performance in the field, as part of a process to qualifying the effectiveness of a curing compound membrane. The curing monitor system, a device capable of accurately recording relative humidity and temperature at three critical locations along with wind speed and solar radiation, is used as part of a test procedure to assess the efficacy of a curing compound. A compound curing evaluation index (EI) is defined in terms of the effective curing thickness concept and moisture loss at 24 h after placement. The EI is useful to rank the curing compound relative to laboratory test conditions. From the limited field application studies, it has been observed that the proposed test procedure has good potential to be an effective tool to assess CE and quality under field conditions. DOI: 10.1061/(ASCE)MT.1943-5533.0000068 CE Database subject headings: Curing; Evaporation; Hydration; Humidity; Concrete; Cracking; Shrinkage. Author keywords: Curing compound; Curing quality; Effective curing thickness; Evaluation index; Potential evaporation; Curing effective index.

We present a new technique for fabricating compliant mechanisms from stamped metal sheets. The concept works by providing thinned segments to allow rotation of flexural beams 90 deg about their long axis, effectively providing a flexure as wide as the sheet's thickness. The method is demonstrated with the design and fabrication of a metal bistable mechanism for use as a threshold accelerometer. A new model based on elliptic integral solutions is presented for bistable mechanisms incorporating long, thin flexures. The resulting metal bistable mechanisms are tested for acceleration threshold sensing using a drop test and a vibration test. The mechanisms demonstrate very little variation due to stress relaxation or temperature effects. The force-displacement behavior of a mechanism is also measured. The mechanisms' switching force is less than the designed value because of out-of-plane motion and dynamic effects. [DOI: 10.1115/1.4001876]

Actual hypoid gear tooth surfaces do deviate from the theoretical ones either globally due to manufacturing errors or locally due to reasons such as tooth surface wear. A practical methodology based on ease-off topography is proposed here for loaded tooth contact analysis of hypoid gears having both local and global deviations. This methodology defines the theoretical pinion and gear tooth surfaces from the machine settings and cutter parameters, and constructs the surfaces of the theoretical ease-off and roll angle to compute for the unloaded contact analysis. This theoretical ease-off topography is modified based on tooth surface deviations and is used to perform a loaded tooth contact analysis according to a semi-analytical method proposed earlier. At the end, two examples, a face-milled hypoid gear set having local deviations and a face-hobbed one having global deviations, are analyzed to demonstrate the effectiveness of the proposed methodology in quantifying the effect of such deviations on the load distribution and the loaded motion transmission error. [DOI: 10.1115/1.4001722] Keywords: hypoid gears, ease-off topography, loaded tooth contact, surface deviations

Production split and merge operations are widely used in many manufacturing systems to increase production capacity and variety, improve product quality, and carry out scheduling and control activities. This article presents analytical methods to analyze split and merge production systems with exponential machine reliability models, operating under circulate, strictly circulate, priority, and percentage split/merge policies. In addition to developing the recursive procedures for performance analysis, the structural properties of the systems and the impacts of routing policies on system performance are investigated. Keywords: Split, merge, throughput, percentage, priority, circulate, strictly circulate, 1. Introduction In modern manufacturing systems, split and merge structures are often used to increase production capacity and variety, improve product quality, and carry out scheduling and control activities. The [...]

In this paper, seven reinforced concrete-block shear walls with aspect ratios of 1.5 and 2.2 (two- and three-storey high) were tested under displacement-controlled cyclic loading. The response of rectangular, flanged, and end-confined walls, designed to have the same lateral resistance when subjected to the same axial load, is discussed. In general, high levels of ductility accompanied by relatively small strength degradation were observed in all walls with a significant increase in ductility and displacement capabilities for the flanged and end-confined walls compared to the rectangular ones. For both aspect ratios evaluated, the drift levels at 20% strength degradation were 1.0, 1.5, and 2.2% corresponding to the rectangular, the flanged, and the end-confined walls, respectively. The ductility values of the proposed flanged and end-confined walls were, respectively, 1.5 and 2 times those of their rectangular wall counterparts (with the same overall length and aspect ratio). In addition to the enhanced ductility, a saving of more than 40% in the amount of vertical reinforcement was achieved using the proposed alternative strategies while maintaining the same lateral wall resistance. Existing design clauses were used to predict the wall capacities using the American and the Canadian masonry codes and showed excellent agreement. This will facilitate adoption of the new construction categories with minimal modifications to existing code clauses. The test results indicate that higher ductility than the currently endorsed values by North American codes should be used for rectangular walls. Moreover, higher values should be expected when the proposed strategies are adopted which would significantly reduce the seismic demand on reinforced concrete-block shear wall construction. DOI: 10.1061/(ASCE)ST.1943-541X.0000164 CE Database subject headings: Concrete; Masonry; Cyclic loads; Ductility; Experimentation; Flanges; Seismic tests; Shear walls. Author keywords: Concrete masonry; Cyclic loads; Ductility; Experimental tests; Flanges; Seismic tests; Shear walls.

A study investigating the modal properties and dynamic response of several laboratory-constructed and in situ floors supported with cold-formed steel C-shaped joists for floors was conducted. The tested floors were typical of residential midrise applications, with oriented-strand board, FORTACRETE, and cold-formed steel deck subfloors, both with and without lightweight concrete topping. Details including span, large lip-reinforced web openings, subfloor, topping, strongback, and framing condition were varied to observe their influence on the fundamental frequency, damping ratio, and deflection. Suggestions for the design and remediation of floors where vibration serviceability is a concern are given. Laboratory tested floor systems were generally found to be the worst-case scenario for the natural frequency and damping ratio. Furniture and finishes were found to not appreciably change the performance of a floor system. The responses of the floor systems tested in this study were evaluated against the ISO 2631 limit for maximum acceleration and Onysko's static deflection limit, as presented in ATC Design Guide 1: Minimizing Floor Vibration. The in situ floors examined were found to have performed within the acceptable range, as defined by the two criteria. DOI: 10.1061/(ASCE)ST.1943-541X.0000168 CE Database subject headings: Floors; Vibration; Cold-formed steel; Joists; Natural frequency; Damping. Author keywords: Floor vibration; Floor vibration performance; Lightweight floor; Cold-formed steel C-shaped joist; Natural frequency; Damping ratio.

This paper presents the physical properties of recycled asphalt pavement (RAP) and its influence on the mechanical performance of a binder course asphalt pavement mix. A series of binder course mixes were designed containing varying percentages of RAP. A mix made from only virgin material was selected as the control mix for the investigation. The effect of introducing RAP into the binder course mix was evaluated through a series of laboratory tests including the Marshall test, the indirect tensile stiffness modulus test, the indirect tensile fatigue test and the water sensitivity test. A circular wheel track (CWT) was developed in order to study the dynamic effects of a rolling wheel traveling over an asphalt pavement. The CWT was commissioned within a temperature controlled room along with a customized data acquisition system. The system involves the testing of rectangular slabs and allows for the investigation of dynamic tensile strain. The laboratory tests have shown that the introduction of RAP to the binder course mix resulted in an improvement in all mechanical properties. In particular, it was found that the mix containing up to 30% RAP, displayed improved fatigue resistance relative to the control mix manufactured from virgin materials. DOI: 10.1061/(ASCE)MT.1943-5533.0000093 CE Database subject headings: Recycling; Asphalt pavements; Performance characteristics; Base course; Fatigue. Author keywords: Recycling; Asphalt pavements; Performance characteristics.

This paper focuses on the design and performance of a very tall mechanically stabilized earth (MSE) wall. Expansion of Seattle-Tacoma International Airport called for the construction of a third runway west of the two existing runways. A significant volume of compacted earth fill was required to raise the grade as much as 50 m to meet the level of the existing airfield. Nominal 2H: 1V fill slopes were used where possible, but MSE retaining walls were used where fill slopes would have encroached into existing wetlands. Consequently a four-tier 46-m-tall MSE wall was constructed along a portion of the western edge of the embankment. Performance monitoring included strain gauge-instrumented reinforcing strips, inclinometer installations with sondex settlement rings, optical survey of the wall facing for vertical and lateral movements, and piezometers. This paper describes wall design issues, aspects associated with the instrumentation of the wall, and the observed performance. Monitoring indicates satisfactory performance of the MSE wall and compares reasonably well with predicted performance. DOI: 10.1061/(ASCE)GT.1943-5606.0000294 CE Database subject headings: Soil stabilization: Retaining walls; Performance characteristics; Instrumentation; Design; Displacement; Washington; Airport and airfield runways. Author keywords: Soil stabilization; Retaining walls; Performance; Instrumentation; Design; Displacement.

Effective (design) thermal resistivity values for use of rigid, cellular polystyrene foam insulation in below-ground frost-protection applications play an important role in the success of the ASCE 32-01 standard. The ASCE 32-01 standard is currently recognized in U.S. model building codes as a cost-effective means of protecting building foundations against frost heave in regions with seasonal ground freezing and no permafrost. The long-term thermal performance of foundation insulation used for this purpose is, therefore, a critical building performance concern. This same concern also has relevance to sustained performance of below-ground insulation used for energy conservation purposes. This paper provides a critical review and analysis of data reported in the literature on below-ground thermal performance of rigid, cellular polystyrene foam insulations. These products can be molded expanded polystyrene or extruded polystyrene as defined by ASTM C578 in ASTM 2008 Standard. The findings serve to document and confirm effective thermal resistivity values originally incorporated into the ASCE 32-01 standard for frost protection of building foundations. DOI: 10.1061/(ASCE)CR.1943-5495.0000012 CE Database subject headings: Polystyrene; Insulation; Moisture; Thermal factors; Frost; Shallow foundations. Author keywords: Polystyrene; Insulation; Moisture; Below-ground performance; Effective thermal resistivity; Frost protection; EPS; XPS.

A method has been developed for high-accuracy analysis of forced response levels for mistuned bladed disks vibrating in gas flow. Aerodynamic damping, the interaction of vibrating blades through gas flow, and the effects of structural and aerodynamic mistuning are included in the bladed disk model. The method is applicable to cases of high mechanical coupling of blade vibration through a flexible disk and, possibly shrouds, to cases with stiff disks and low mechanical coupling. The interaction of different families of bladed disk modes is included in the analysis providing the capability of analyzing bladed disks with pronounced frequency veering effects. The method allows the use of industrial-size sector models of bladed disks for analysis of forced response of a mistuned structure. The frequency response function matrix of a structurally mistuned bladed disk is derived with aerodynamic forces included. A new phenomenon of reducing bladed disk forced response by mistuning to levels that are several times lower than those of their tuned counterparts is revealed and explained. [DOI: 10.1115/1.4000117]

An analytical model is generated that allows the evaluation of the compression system. It is also used to derive general rules for optimizing a system. Several strategies for the compression system (single compressors, multiple compressors with a single driver in series and parallel configuration, and multiple compressors with individual drivers) are evaluated based on the said model. [DOI: 10.1115/1.4000147]

In this article, the performance of a two degree-of-freedom dynamic vibration absorber (DVA) with very large or very small moment of inertia is studied. Although it has been shown previously that an optimally tuned DVA with a negligibly small moment of inertia marginally outperforms the optimally tuned DVA with a very large moment of inertia, the physical reasons for this have not been made clear. Using a simplified model of the stiffness elements of the DVA, it is shown that the two sets of parallel combinations of stiffness and damping elements of the DVA with negligibly small moments of inertia effectively act in series, rather than in parallel as in the other case. Furthermore, it is shown that the stiffness and damping elements can be represented as a single stiffness and a single damping element whose properties are frequency dependent. This frequency dependency means that there is additional freedom in choosing the optimum stiffness and damping of the DVA, which results in better performance. [DOI: 10.1115/1.4000780]

In Part I of this work, a theoretical analysis showed that the surrounding air in the closed confinement between rotor and casing has a significant effect on the dynamic behavior of high speed minirotors. In order to validate the developed theoretical model an experimental setup is designed and the dynamic behavior of the rotor with medium gap confinement is studied. The experimental setup has flexible supports, which consist of beams with adjustable length. The support stiffness is changed by altering the beam length. Modal analysis of the rotor is done in free-free conditions in order to test the capability of the rotordynamic model without the supports and multiphysical effects. The experimental and simulation results agree well with a difference of 1%. Then modal analysis of the whole structure is done at standstill and during operation in the absence of the casing. In this way, multiphysical effects are eliminated and only support effects on the dynamics of the structure are observed. The supports appear to have significant effect on the natural frequencies of the flexural modes of the system. Different support modeling techniques are studied and adequate equivalent models are obtained. These models are then implemented into the structural model of the rotor. Finally, multiphysical effects are tested at different speeds with different support stiffnesses. Experiments are performed with and without the casing for determining the change in the natural frequencies and onset of instability. The surrounding fluid has a significant effect on the stability of the system while the natural frequencies do not change significantly. The experimental and theoretical results are in fair agreement for predicting the natural frequencies and the onset of instability. [DOI: 10.1115/1.4000788]

Experimental investigations of synchronization of linearly diffusive coupled van der Pol electronic oscillators are reported. In addition to in-and antiphase stable oscillations, shifted symmetric and asymmetric trajectories have been observed experimentally. However, the experiments have failed to produce stable chaotic behavior in these systems. Extended numeric simulations are then performed to show that the previously believed chaotic region is a transient numeric effect, thereby validating experimental results. [DOI: 10.1115/1.4000808]

With the combination of the gold nanoparticle (AuNP)-based visual test with hollow fiber supported liquid membrane (HFSLM) extraction, a highly sensitive and selective method was developed for field detection of mercuric ion ([Hg.sup.2+]) in environmental waters. [Hg.sup.2+] in water samples was extracted through HFSLM and trapped in the aqueous acceptor and then visually detected based on the red-to-blue color change of 3-mercaptopropionic acid-functionalized AuNP (MPA-AuNP) probe. The highest extraction efficiency of [Hg.sup.2+] was obtained by using a 600 mL sample (pH 8.0, 2.0% (w/v) NaCl), ~35 [micro]L of acceptor (10 mM of 2,6-pyridinedicarboxylic acid, pH 4.0) filled in the lumen of a polypropylene hollow fiber tubing (55 cm in length, 50 [micro]m wall thickness, 280 [micro]m inner diameter), a liquid membrane of 2.0% (w/v) trioctycphosphine oxide in undecane, and a shaking rate of 250 rpm. The chromegenic reaction was conducted by incubating the mixture of MPA-AuNP stock solution (12 [micro]L, 15 nM), Tris-borate buffer solution (18 [micro]L, 0.2 M, pH 9.5), and acceptor (30 [micro]L) at 30[degrees]C for 1 h. The detection limit can be adjusted to 0.8 [micro]g/L [Hg.sup.2+] (corresponding to an enrichment factor of ~1000 in the HFSLM) and 2.0 [micro]g/L [Hg.sup.2+] (the U.S. Environmental Protection Agency limit of [[Hg.sup.2+]] for drinkable water) by using extraction times of 3 and 1 h, respectively. The proposed method is extremely specific for [Hg.sup.2+] with tolerance to at least 1000-fold of other environmentally relevant heavy and transition metal ions and was successfully applied to detect [Hg.sup.2+] in a certified reference water sample, as well as real river, lake, and tap water samples. 10.1021/ac100541s

In switched-control methodology, which integrates several controllers handling different environmental conditions for dynamic positioning (DP) systems in marine vessels, the supervisor uses the estimated wave peak frequency (WPF) to classify the existing environmental condition so as to switch to the appropriate controller. The WPF is assumed to be the same as the peak frequency of the vessel's response spectrum at wave frequency estimated by fast Fourier transform (FFT) of the measured position and heading. Using a short window width leads to error in the WPF estimation whereas a longer width causes a significant time lag in control activation. This paper addresses the effect of uncertainty in the estimation of WPF by FFT on the reliability of the switched-controller based DP vessel. The probability of the supervisor switching to a wrong controller due to WPF estimation error is first evaluated for four different environmental conditions. The failure probabilities of the system with and without WPF uncertainty are then evaluated and compared. Numerical simulation based on a supply vessel shows that the increase in failure probability of the switched-controller DP system due to the uncertainty in the estimated WPF by FFT is not significant compared with the failure probability of a perfect switched-controller DP system. [DOI: 10.1115/1.4000392]

A procedure for the experimental convergence evaluation of a hydraulic-network solver is proposed, based on using genetic algorithms to search for network parameter values that maximize the number of iterations of the hydraulic-network solver under test. The efficiency of the method is demonstrated by the example of convergence evaluation for the EPANET hydraulic simulator. Examples of a pipe network and of combinations of parameter values for which the static solver of the simulator fails to converge in a reasonable number of iterations are given. The features of the EPANET 2.00.12 solver responsible for loss of convergence are discussed. New criteria for the automatic start of solution damping aimed at improving the convergence of the solver are proposed. The better convergence of the EPANET solver modified in accordance with these criteria is confirmed by the random and the proposed search-based testing method. DOI: 10.1061/(ASCE)HY.1943-7900.0000179 CE Database subject headings: Hydraulic networks; Simulation models; Convergence; Algorithms; Experimentation. Author keywords: Water distribution; Simulation models; Convergence analysis; Genetic algorithm.

Cold in-place recycling (CIR) is one of the most effective methods to rehabilitate asphalt pavements. In fact, most CIR roads have performed well at low cost in Iowa since the first CIR road was constructed in 1986. However, some CIR roads have reached failures earlier than their expected design lives because there is no design standard for designing CIR roads with a limited amount of past performance information. Some of the most prominent problems seemed to have come from selecting CIR in areas where there are poor subgrades. Therefore, it is critical to collect CIR performance data along with falling weight deflectometer (FWD) data in order to develop performance models. The main purpose of this paper is to document that effort. The performance models were developed on the basis of historical data collected from CIR roads in Iowa. First, an inventory of CIR roads was created which includes construction information, subgrade and base characteristics, and traffic levels. In consideration of pavement age, level of traffic, and subgrade condition, 26 test sections were selected from the inventory of CIR roads and pavement surface distress surveys were conducted on these roads using an automated image collection system. Distress data were then compiled to compute pavement condition index (PCI) for each test section. FWD data were collected from each test section to determine its relative soil support condition. Finally, to determine their long-term performance, the PCI values were plotted against the pavement age for each group of pavements categorized by their soil support conditions and traffic levels. Overall, it can be concluded that the CIR roads in Iowa, all under traffic level of annual average daily traffic of 2,000, have performed very well and predicted to last up to 25 years before reaching the poor condition (PCI = 40) when the pavements are to be rehabilitated. The CIR roads with a good subgrade support, however, are predicted to last up to 35 years. DOI: 10.1061/(ASCE)CF.1943-5509.0000093 CE Database subject headings: Asphalt pavements; Recycling; Service life; Stress; Measurement; Iowa. Author keywords: Asphalt pavements; Recycling; Service life; Distress; Measurement.

This paper presents a study to determine the optimal rolling patterns for chip seals based on aggregate retention performance. Chip seal sections composed of single seals of granite 78M and CRS-2 emulsion are constructed using five different rolling patterns with two or three rollers. Both pneumatic tire and combination rollers are used in developing these patterns. Chip seal samples are obtained from the sections for laboratory testing. The aggregate retention performance is evaluated using the flip-over test, Vialit test, and the third-scale model mobile loading simulator. It is found that the time delay between aggregate spreading and rolling is an important parameter for the aggregate retention performance. The laboratory aggregate retention test results are used along with typical roller speeds and the maximum allowable time delay between aggregate spreading and rolling to develop optimal rolling patterns for two and three rollers. DOI: 10.1061/(ASCE)CF.1943-5509.0000096 CE Database subject headings: Aggregates; Pavements; Construction materials; Failures. Author keywords: Chip seal; Rolling pattern; MMLS3; Aggregate retention; Delayed rolling time.

Performance of an axial flow fan unit is closely related to its tip leakage mass flow rate and level of tip/casing interactions. The present experimental study uses a stereoscopic particle image velocimeter to quantify the three dimensional mean flow observed near the blade tip, just downstream of a ducted fan unit. After a comprehensive description of the exit flow from the baseline fan, a number of novel tip treatments based on custom designed pressure side extensions are introduced. Various tip leakage mitigation schemes are introduced by varying the chordwise location and the width of the extension in the circumferential direction. The current study shows a proper selection of the pressure side bump location and width are the two critical parameters influencing the success of each tip leakage mitigation approach. Significant gains in the axial mean velocity component are observed when a proper pressure side tip extension is used. It is also observed that a proper tip leakage mitigation scheme significantly reduces the tangential velocity component near the tip of the axial fan blade. Reduced tip clearance related flow interactions are essential in improving the energy efficiency of ducted fan systems. A reduction or elimination of the momentum deficit in tip vortices is also essential to reduce the adverse performance effects originating from the unsteady and highly turbulent tip leakage flows rotating against a stationary casing. [DOI: 10.1115/1.4001540]

A windowed internally circulating fluidized bed reactor was tested using m-Zr[O.sub.2]-supported Ni[Fe.sub.2][O.sub.4] (Ni[Fe.sub.2][O.sub.4]/ m-Zr[O.sub.2]) particles as redox material for thermochemical two-step water splitting to produce hydrogen from water. The internally circulating fluidized bed of Ni[Fe.sub.2][O.sub.4]/m-Zr[O.sub.2] particles is directly heated by solar-simulated Xe light irradiation through a transparent quartz window mounted on top of the reactor. A sun simulator with three Xe lamps at laboratory scale has been newly installed in our laboratory for testing the fluidized bed reactor. The input power of incident Xe light can be scaled up to 2.6 [kW.sub.th]. Temperature distributions within the fluidized bed are measured under concentrated Xe light irradiation with an input power of 2.6 [kW.sub.th]. Hydrogen productivity and reactivity for the fluidized bed of Ni[Fe.sub.2][O.sub.4]/m-Zr[O.sub.2] particles are examined using two different reactors under the [N.sub.2] flow rate and flow ratio, which yield a higher bed temperature. The feasibility of successive two-step water splitting using the fluidized bed reactor is examined by switching from [N.sub.2] gas flow in the thermal reduction step to a steam/[N.sub.2] gas mixture in the water decomposition step. It is confirmed that hydrogen production takes place in the single fluidized bed reactor by successive two-step water splitting. [DOI: 10.1115/1.4001154]

The influence of a dye adsorption solvent of an infrared organic dye (NK-6037) on solar cell performance was investigated in a mesoporous Ti[O.sub.2] dye-sensitized solar cell (DSC). Various types of alcohols and a mixture of ethanol and tertiary-butanol (t-butanol) were applied as dye adsorption solvents. It was confirmed that the species of dye adsorption solvent significantly influences the performance of a DSC. Decreasing the specific dielectric constant of the dye adsorption solvent caused the amount of dye adsorbed on the Ti[O.sub.2] photoelectrode to increase dramatically. It is suggested that the specific dielectric constant of the dye adsorption solvent influences the solvation state of the NK-6037 dye in the solvent, thus determining, for instance, whether the dye is in the monomer state or the aggregate state. Interestingly, solar cell performance was not linearly proportional to the adsorbed amount of dye but a precise optimum amount of adsorbed dye was required for the best performance of the DSC. The optimum amount of adsorbed dye was approximately 5.0 x [10.sup.-8] mol/[cm.sup.2] and it was obtained by using solvents having a dielectric constant of approximately 18. This condition was realized by 1-butanol, 2-propanol, and a mixture of ethanol and t-butanol with a volume ratio of 7:3. The best efficiency obtained for the DSC was 1.7%, using the optimum amount of the adsorbed infrared dye NK-6037. It is speculated that an excess of dye on the Ti[O.sub.2] photoelectrode accelerates the formation of H-type dye aggregates, resulting in a decrease in short circuit photocurrent ([J.sub.sc]) by unfavorable side reactions of electron loss. It is demonstrated that dye adsorption solvent selection is the critical factor in obtaining high performance in a DSC [DOI: 10.1115/1.4001171] Keywords: dye-sensitized solar cell, infrared organic dye, dye adsorption solvent

A prototype direct absorption central receiver, called the solid particle receiver (SPR), was built and evaluated on-sun at power levels up to 2.5 [MW.sub.th] at Sandia National Laboratories in Albuquerque, NM. The SPR consists of a 6 m tall cavity through which spherical sintered bauxite particles are dropped and directly heated with concentrated solar energy. In principle, the particles can be efficiently heated to a temperature in excess of 900 [degrees]C, well beyond the stability limit of existing nitrate salt formulations. The heated particles may then be stored in a way analogous to nitrate salt systems, enabling a dispatchable thermal input to power or fuel production cycles. The focus of this current effort was to provide an experimental basis for the validation of computational models that have been created to support improved designs and further development of the solid particle receiver. In this paper, we present information on the design and construction of the solid particle receiver and discuss the development of a computational fluid dynamics model of the prototype. We also present experimental data and model comparisons for on-sun testing of the receiver over a range of input power levels front 1.58-2.51 [MW.sub.th]. Model validation is performed using a number of metrics including particle velocity; exit temperature, and receiver efficiency. In most cases, the difference between the model predictions and data is less than 10%. [DOI: 10.1115/1.4001146]