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Actual Test (actual + test)
Selected AbstractsIdentification of some optimal parameters to achieve higher laminate quality through tape placement processADVANCES IN POLYMER TECHNOLOGY, Issue 2 2010Muhammad Amir Khan Abstract Investigations of the tape placement process are still underway to achieve the laminate quality comparable with other highly developed composite manufacturing methods, such as autoclave-based processes. The evaluation of the products and the mechanical properties of the material has revealed regions where some upgrading could bring significant enhancement in performance. This study is concerned with issues related to the characterization of material properties, interlaminar bond development, and ways of optimizing process parameters. These include heating, layup velocity, tool temperature, and consolidation force, which were studied to determine their effects on the mechanical strength of the composites produced. The bonding degree of the laminates was simulated taking into account a combination of process parameters, comparing the predictions with the actual test results. The thermal stability of the polyether ether ketone matrix, in relation to the processing conditions used in the manufacture, and their effects on the interlaminar bonding stability were also investigated and explained. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:98,111, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20177 [source] Prospect theory analysis of guessing in multiple choice testsJOURNAL OF BEHAVIORAL DECISION MAKING, Issue 4 2002Yoella Bereby-Meyer Abstract The guessing of answers in multiple choice tests adds random error to the variance of the test scores, lowering their reliability. Formula scoring rules that penalize for wrong guesses are frequently used to solve this problem. This paper uses prospect theory to analyze scoring rules from a decision-making perspective and focuses on the effects of framing on the tendency to guess. In three experiments participants were presented with hypothetical test situations and were asked to indicate the degree of certainty that they thought was required for them to answer a question. In accordance with the framing hypothesis, participants tended to guess more when they anticipated a low grade and therefore considered themselves to be in the loss domain, or when the scoring rule caused the situation to be framed as entailing potential losses. The last experiment replicated these results with a task that resembles an actual test. Copyright © 2002 John Wiley & Sons, Ltd. [source] Cultural variations in pre-emptive effort downplayingASIAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 1 2009Reinier P. Pualengco Pre-emptive effort downplaying (PED) occurs when people publicly downplay their effort expenditure on test preparation prior to taking a test for the sake of managing the social evaluation of the self in the face of a challenging performance task. Thirty Asian Americans and 29 European Americans had two opportunities to publicly report their effort expenditure on a practice exercise. They also completed measures of self-evaluations and concern for performance before working on the practice exercise, and the self-evaluation measure again at the completion of the actual test. Only European Americans showed PED. Additionally, concern for performance was positively associated with and mediated cultural variations in PED. The implications of these results are discussed. [source] Equivalent force control method for generalized real-time substructure testing with implicit integrationEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 9 2007Bin Wu Abstract This paper presents a new method, called the equivalent force control method, for solving the nonlinear equations of motion in a real-time substructure test using an implicit time integration algorithm. The method replaces the numerical iteration in implicit integration with a force-feedback control loop, while displacement control is retained to control the motion of an actuator. The method is formulated in such a way that it represents a unified approach that also encompasses the effective force test method. The accuracy and effectiveness of the method have been demonstrated with numerical simulations of real-time substructure tests with physical substructures represented by spring and damper elements, respectively. The method has also been validated with actual tests in which a Magnetorheological damper was used as the physical substructure. Copyright © 2007 John Wiley & Sons, Ltd. [source] Thermodynamic analysis of two-step solar water splitting with mixed iron oxidesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2009Martin Roeb Abstract A two-step thermochemical cycle for solar production of hydrogen from water has been developed and investigated. It is based on metal oxide redox pair systems, which can split water molecules by abstracting oxygen atoms and reversibly incorporating them into their lattice. After successful experimental demonstration of several cycles of alternating hydrogen and oxygen production, the present work describes a thermodynamic study aiming at the improvement of process conditions and at the evaluation of the theoretical potential of the process. In order to evaluate the maximum hydrogen production potential of a coating material, theoretical considerations based on thermodynamic laws and properties are useful and faster than actual tests. Through thermodynamic calculations it is possible to predict the theoretical maximum output of H2 from a specific redox-material under certain conditions. Calculations were focussed on the two mixed iron oxides nickel,iron-oxide and zinc,iron-oxide. In the simulation the amount of oxygen in the redox-material is calculated before and after the water-splitting step on the basis of laws of thermodynamics and available material properties for the chosen mixed iron oxides. For the simulation the commercial Software FactSage and available databases for the required material properties were used. The analysis showed that a maximum hydrogen yield is achieved if the reduction temperature is raised to the limits of the operation range, if the temperature for the water splitting is lowered below 800°C and if the partial pressure of oxygen during reduction is decreased to the lower limits of the operational range. The predicted effects of reduction temperature and partial pressure of oxygen could be confirmed in experimental studies. The increased hydrogen yield at lower splitting temperatures of about 800°C could not be confirmed in experimental results, where a higher splitting temperature led to a higher hydrogen yield. As a consequence it can be stated that kinetics must play an important role especially in the splitting step. Copyright © 2009 John Wiley & Sons, Ltd. [source] |