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Model Tests (model + test)
Selected AbstractsModel test of the relationship between self-help-promoting nursing interventions and self-care and health status outcomesRESEARCH IN NURSING & HEALTH, Issue 2 2004Grace J. Kreulen Abstract In this study of a nursing intervention outcomes model was tested. Path analysis techniques were used to examine predicted relationships between self-help-promoting interventions and patient outcomes of self-care practice and client morbidity at three times. A sample of 307 women receiving medical treatment for breast cancer provided data for the study. The average participant was White, middle-aged, married, educated, and in stage I or stage II disease. Findings support the hypothesized model linking these nursing interventions directly to self-care outcomes and self-care to client morbidity outcomes. Client factors of age, social network size, disease stage, receipt of chemotherapy, resourcefulness, and uncertainty significantly influenced predicted relationships. Examination of specific patterns of relationships for the sample revealed delayed behavioral responses to the interventions, variability in predictors of each outcome at the three measurement times and a more strongly predictive model when patient outcomes were considered within the context of client factors. © 2004 Wiley Periodicals, Inc. Res Nurs Health 27:97,109, 2004 [source] Parameterizing redistribution and sublimation of blowing snow for hydrological models: tests in a mountainous subarctic catchmentHYDROLOGICAL PROCESSES, Issue 18 2009Matthew K. MacDonald Abstract Model tests of blowing snow redistribution and sublimation by wind were performed for three winters over a small mountainous sub-Arctic catchment located in the Yukon Territory, Canada, using a physically based blowing snow model. Snow transport fluxes were distributed over multiple hydrological response units (HRUs) using inter-HRU snow redistribution allocation factors (SR). Three SR schemes of varying complexity were evaluated. Model results show that end-of-winter snow accumulation can be most accurately simulated using a physically based blowing snow model when SR values are established when taking into account wind direction and speed and HRU aerodynamic characteristics, along with the spatial arrangement of the HRUs in the catchment. With the knowledge that snow transport scales approximately with the fourth power of wind speed (u4), SR values can be (1) established according to the predominant u4 direction and magnitude over a simulation period or (2) can change at each time step according to a measured wind direction. Unfortunately, wind direction data were available only for one of the three winters, so the latter scheme was tested only once. Although the aforementioned SR schemes produced different results, model efficiency was of similar merit. The independent effects of topography and vegetation were examined to assess their importance on snow redistribution modelling over mountainous terrain. Snow accumulation was best simulated when including explicit representations of both landscape vegetation (i.e. vegetation height and density) and topography (i.e. wind exposure). There may be inter-basin differences in the relative importance of model representations of topography and vegetation. Copyright © 2009 John Wiley & Sons, Ltd. [source] Experimental study of dynamic damage of an arch damEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 3 2007Haibo Wang Abstract Seismic responses of a 292-m high arch dam were studied by experiment on a shaking table. The model system included the arch dam with contraction joints, a part of a reservoir, and a partial foundation with a topographic feature near the dam. Potential rock wedges on the abutments and the mechanical properties including uplift on the kinematic planes were carefully simulated. A damping boundary consisting of a viscous liquid was introduced to simulate the effect of dynamic energy emission to far field, which made the dynamic interaction between the dam and the foundation be adequately represented in the model test of an arch dam system. Dynamic responses of the arch dam system under a sequence of seismic loadings in increasing strength were examined. Eleven cracks or overstresses on the model dam due to the earthquake excitations were observed, and consequently, its natural frequency dropped by about 14%, but the model dam was stable under the hydrostatic load of the impounded water after the test. Copyright © 2006 John Wiley & Sons, Ltd. [source] Consistency of dynamic site response at Port IslandEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2001Laurie G. Baise Abstract System identification (SI) methods are used to determine empirical Green's functions (EGF) for soil intervals at the Port Island Site in Kobe, Japan and in shake table model tests performed by the Port and Harbor Research Institute (PHRI) to emulate the site during the 17 January 1995 Hyogo-ken Nanbu earthquake. The model form for the EGFs is a parametric auto-regressive moving average (ARMA) model mapping the ground motions recorded at the base of a soil interval to the top of that interval, hence capturing the effect of the soil on the through-passing wave. The consistency of site response at Port Island before, during, and after the mainshock is examined by application of small motion foreshock EGFs to incoming ground motions over these time intervals. The prediction errors (or misfits) for the foreshocks, the mainshock, and the aftershocks, are assessed to determine the extent of altered soil response as a result of liquefaction of the ground during the mainshock. In addition, the consistency of soil response between field and model test is verified by application of EGFs calculated from the shake table test to the 17 January input data. The prediction error is then used to assess the consistency of behaviour between the two cases. By using EGFs developed for small-amplitude foreshock ground motions, ground motions were predicted for all intervals of the vertical array except those that liquefied with small error. Analysis of the post-liquefied ground conditions implies that the site response gradually returns to a pre-earthquake state. Site behaviour is found to be consistent between foreshocks and the mainshock for the native ground (below 16 m in the field) with a normalized mean square error (NMSE) of 0.080 and a peak ground acceleration (PGA) of 0.5g. When the soil actually liquefies (change of state), recursive models are needed to track the variable soil behaviour for the remainder of the shaking. The recursive models are shown to demonstrate consistency between the shake table tests and the field with a NMSE of 0.102 for the 16 m to surface interval that liquefied. The aftershock ground response was not modelled well with the foreshock EGF immediately after the mainshock (NMSE ranging from 0.37 to 0.92). One month after the mainshock, the prediction error from the foreshock modeled was back to the foreshock error level. Copyright © 2001 John Wiley Sons, Ltd. [source] Mating signal partitioning in multi-species assemblages: a null model test using frogsECOLOGY LETTERS, Issue 3 2003Andrew A. Chek Abstract Competitive partitioning of ,community' signal space has long been suggested to underlie diversification of mating signals. Selection or competitive exclusion is expected to reduce overlap of signals, minimizing destructive interference or reducing mismating. We used null models backed by simulation of type I and II error rates to test for evidence of structuring within 11 frog advertisement call assemblages. Within three assemblages, we found significant over-dispersion and regularity-of-spacing in dominant frequency and in pulse rate, consistent with a signal interference hypothesis and signal confusion hypothesis, respectively. Observed partitioning could represent signal evolution or could result from selection on assemblage composition. Most assemblages showed no acoustic partitioning possibly because: (i) partitioning is more readily apparent in female preference, calling times or sites, rather than call attributes; (ii) assemblages have not yet accommodated recently arrived species, or are compositionally unstable so that acoustic accommodation cannot occur; and (iii) evidence of partitioning is only likely where the acoustic space is densely packed. [source] Standsicherheitsuntersuchung für ein räumliches Böschungssystem , Berechnung mit einem zusammengesetzten dreidimensionalen Bruchmechanismus und Modellversuch im Gelände , Teil 2: Durchführung der Berechnung und ErgebnisseBAUTECHNIK, Issue 1 2004Michael Goldscheider Dr.-Ing. Für die Berechnung der Sicherheit gegen einen räumlichen Grabenbruch an einer hohen Randböschung eines Braunkohletagebaus wird ein räumlicher zusammengesetzter Starrkörperbruchmechanismus entwickelt und berechnet. Die Grundlagen und Grundgleichungen wurden in Teil 1 behandelt. Der Teil 2 beschreibt die Durchführung der Berechnung, die Optimierung des Bruchmechanismus und typische Berechnungsergebnisse. Stability analysis for a three-dimensional slope system , calculation with a composed rigid body failure mechanism and model test in an open site. Part2: Execution of the calculation and results. To determine the safety factor against a three-dimensional graben rupture on a high rim slope of an open-cast lignite mine a three-dimensional composed rigid body failure mechanism is outlined and calculated. The basic relations and equations are presented in part 1 of this paper. In the part 2 the execution of calculation, the optimization of the failure mechanism and typical results are described. [source] Consistency of dynamic site response at Port IslandEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2001Laurie G. Baise Abstract System identification (SI) methods are used to determine empirical Green's functions (EGF) for soil intervals at the Port Island Site in Kobe, Japan and in shake table model tests performed by the Port and Harbor Research Institute (PHRI) to emulate the site during the 17 January 1995 Hyogo-ken Nanbu earthquake. The model form for the EGFs is a parametric auto-regressive moving average (ARMA) model mapping the ground motions recorded at the base of a soil interval to the top of that interval, hence capturing the effect of the soil on the through-passing wave. The consistency of site response at Port Island before, during, and after the mainshock is examined by application of small motion foreshock EGFs to incoming ground motions over these time intervals. The prediction errors (or misfits) for the foreshocks, the mainshock, and the aftershocks, are assessed to determine the extent of altered soil response as a result of liquefaction of the ground during the mainshock. In addition, the consistency of soil response between field and model test is verified by application of EGFs calculated from the shake table test to the 17 January input data. The prediction error is then used to assess the consistency of behaviour between the two cases. By using EGFs developed for small-amplitude foreshock ground motions, ground motions were predicted for all intervals of the vertical array except those that liquefied with small error. Analysis of the post-liquefied ground conditions implies that the site response gradually returns to a pre-earthquake state. Site behaviour is found to be consistent between foreshocks and the mainshock for the native ground (below 16 m in the field) with a normalized mean square error (NMSE) of 0.080 and a peak ground acceleration (PGA) of 0.5g. When the soil actually liquefies (change of state), recursive models are needed to track the variable soil behaviour for the remainder of the shaking. The recursive models are shown to demonstrate consistency between the shake table tests and the field with a NMSE of 0.102 for the 16 m to surface interval that liquefied. The aftershock ground response was not modelled well with the foreshock EGF immediately after the mainshock (NMSE ranging from 0.37 to 0.92). One month after the mainshock, the prediction error from the foreshock modeled was back to the foreshock error level. Copyright © 2001 John Wiley Sons, Ltd. [source] The contributions of topoclimate and land cover to species distributions and abundance: fine-resolution tests for a mountain butterfly faunaGLOBAL ECOLOGY, Issue 2 2010Javier Gutiérrez Illán ABSTRACT Aim, Models relating species distributions to climate or habitat are widely used to predict the effects of global change on biodiversity. Most such approaches assume that climate governs coarse-scale species ranges, whereas habitat limits fine-scale distributions. We tested the influence of topoclimate and land cover on butterfly distributions and abundance in a mountain range, where climate may vary as markedly at a fine scale as land cover. Location, Sierra de Guadarrama (Spain, southern Europe) Methods, We sampled the butterfly fauna of 180 locations (89 in 2004, 91 in 2005) in a 10,800 km2 region, and derived generalized linear models (GLMs) for species occurrence and abundance based on topoclimatic (elevation and insolation) or habitat (land cover, geology and hydrology) variables sampled at 100-m resolution using GIS. Models for each year were tested against independent data from the alternate year, using the area under the receiver operating characteristic curve (AUC) (distribution) or Spearman's rank correlation coefficient (rs) (abundance). Results, In independent model tests, 74% of occurrence models achieved AUCs of > 0.7, and 85% of abundance models were significantly related to observed abundance. Topoclimatic models outperformed models based purely on land cover in 72% of occurrence models and 66% of abundance models. Including both types of variables often explained most variation in model calibration, but did not significantly improve model cross-validation relative to topoclimatic models. Hierarchical partitioning analysis confirmed the overriding effect of topoclimatic factors on species distributions, with the exception of several species for which the importance of land cover was confirmed. Main conclusions, Topoclimatic factors may dominate fine-resolution species distributions in mountain ranges where climate conditions vary markedly over short distances and large areas of natural habitat remain. Climate change is likely to be a key driver of species distributions in such systems and could have important effects on biodiversity. However, continued habitat protection may be vital to facilitate range shifts in response to climate change. [source] Bearing capacity of shallow foundations in transversely isotropic granular mediaINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 8 2010A. Azami Abstract The main focus in this work is on the assessment of bearing capacity of a shallow foundation in an inherently anisotropic particulate medium. Both the experimental and numerical investigations are carried out using a crushed limestone with elongated angular-shaped aggregates. The experimental study involves small-scale model tests aimed at examining the variation of bearing capacity as a function of the angle of deposition of the material. In addition, the results of a series of triaxial and direct shear tests are presented and later employed to identify the material functions/parameters. The numerical part of this work is associated with the development and implementation of a constitutive framework that describes the mechanical response of transversely isotropic frictional materials. The framework is based on the elastoplasticity and accounts for the effects of strain localization and inherent anisotropy of both the deformation and strength characteristics. The results of numerical simulations are compared withthe experimental data. A parametric study is also carried out aimed at examining the influence of various simplifications in the mathematical framework on its predictive abilities. Copyright © 2009 John Wiley & Sons, Ltd. [source] An application of dynamic positioning control using wave feed forwardINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 13 2001A. B. Aalbers Abstract The paper presents the results of model tests for a large tanker in which wave drift force feed forward was applied in the dynamic positioning control system. The estimation method of the nonlinear (second order) wave drift forces from the measurement of relative water motions at the side of a ship hull is presented. The estimated wave drift forces are used in the DP control system, to enhance the filter process of the extended Kalman filter, and in the required thruster set-points. The EKF uses the nonlinear equations of low-frequency ship motions on the horizontal plane, which are also presented. The results of the model tests show that the use of wave drift force feed forward significantly improves the positioning accuracy in sea states with 3.5 m significant wave height or higher. Copyright © 2001 John Wiley & Sons, Ltd. [source] Werkzeugbeschichtungen für die Trockenbearbeitung,MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 10 2006E. Abele PVD coating; tribology; dry machining; tool wear Abstract Bei der Trockenbearbeitung wirkt an der Werkzeugschneide ein Belastungskollektiv aus mechanischen, thermischen und chemischen Einflussgrößen. Im Vergleich zur konventionellen Bearbeitung unter Verwendung von Vollstrahl-Emulsionskühlung erhöht die Trockenbearbeitung die auf den Schneidkeil wirkenden Belastungen. Eine sehr gute Möglichkeit die Schneide vor thermischen, abrasiven und tribo-oxidativem Verschleißangriff zu schützen stellt die Verwendung von PVD Beschichtungen dar. Neu entwickelte PVD Beschichtungen aus CrxAlyYzN, CrxAlyBzN und CrxAlySizN- wurden sowohl im tribologischen Modelltest als auch im realen Zerspanungstest auf ihre Eignung zur Trockenbearbeitung untersucht. In diesem Paper wird neben der verwendeten Beschichtungstechnologie detailliert auf die Schichteigenschaften eingegangen. Im Zusammenhang mit dem im Zerspanungstest gemessenen Verschleißverhalten und der Prozesskräfte werden anschließend Rückschlüsse auf das weitere Optimierungspotential dieser Schichtsysteme gezogen. Tool coatings for dry machining During dry machining a strain collective consisting of mechanical, thermal, and chemical loads is imposed upon the cutting edge. Compared to conventional machining using cooling lubrication fluids, the loads are increased in dry cutting. A feasible solution to protect the cutting edge from thermal wear, abrasion, and tribo-oxidation is the application of hard coatings. Newly developed CrxAlyYzN, CrxAlyBzN and CrxAlySizN PVD coatings were both evaluated in tribological model tests and machining tests concerning their suitability for dry cutting applications. Herein, the used coating technology and the coating properties are described in detail. The measured tool wear and the process forces give further hints for the optimization of the coating system. [source] | |||||||||||||