Spelling suggestions: "subject:"1experimental analysis"" "subject:"15experimental analysis""
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Evaluative interpersonal responses and attributions of attitude: A test of learning theory variablesMone, Robert D. 01 January 1982 (has links)
No description available.
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Multitrait-multimethod matrix assessment of selected neuropsychological instrumentsSweeney, Valerie Kim 01 January 1982 (has links)
No description available.
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The Effects of Reward and Risk Level Associated with Speeded Actions: Evidence from Behavior and ElectroencephalographyChen, Xingjie 25 October 2018 (has links)
Choosing a course of action in our daily lives requires an accurate assessment of the associated risks as well as the potential rewards. The present two studies investigated the mechanism of how reward and risk level influence the motor decisions of speeded actions (Chapter 2) and its neural dynamics (Chapter 3) by focusing on the beta band (15-30 Hz) oscillation patterns reflected in the EEG signals. Participants performed a modified version of the Go-NoGo task, in which they earned reward points based on the speed and accuracy of response. On each trial, the reward points at stake (120 vs. 6) and the probability that a Go signal would follow (Go-probability) were presented prior to a Go/NoGo signal (Trial Information Period). The behavioral results (from both Chapters 2 and 3) showed that larger amount of rewards can motivate people to respond faster, and this effect was modulated by the assessed risk, suggesting that decisions for actions are based on a systematic trade-off between rewards and risks. The EEG data showed that motor beta oscillations from the two studied brain regions reflected different levels of motivation towards a motor response across different reward and risk levels. Specifically, the lower beta power associated with higher reward and lower risk level. Collectively, the results provide a mechanistic understanding of how motivational cues are translated into action outcomes via modulating patterns of brain oscillations.
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Experimental Investigation of the Air Release in Hydraulic ReservoirsLonghitano, Marco, Protase, Alessandro, Murrenhoff, Hubertus January 2016 (has links)
Air contamination strongly decreases the efficiency of fluid power systems and when the allowable limits are exceeded, the performance of the system deteriorates. The hydraulic reservoir performs the function of releasing the entrained air of the hydraulic system to the surroundings. In recent years, the reservoir design has become an important task in the design of the hydraulic system due to space restrictions forcing the use of small sized reservoirs. Despite this fact, experimental results on an air release are not available. In this paper, an experimental investigation of the air release in hydraulic reservoirs is presented. A test apparatus using an optical method as well as the post-processing of the results is described. These are given in terms of an air release rate for different reservoir designs over a wide range of oil flow rates and air loads. The current study is a significant step forward in the design of fluid power systems, as it provides an experimental procedure to measure the air release in the hydraulic reservoir as well as its quantitative analysis.
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Helically coiled cavity receiver for a micro-scale direct generation steam Rankine cycle using a novel solar dish designSwanepoel, Jonathan Kyle January 2019 (has links)
Sub-Saharan Africa has an underutilised solar resource that is available to provide distributed-scale power to rural communities that are not reached by the current grid systems that are in place. Renewable power generation systems are typically infeasible for this purpose due to their high manufacturing and maintenance costs. This research proposes to address this by experimentally investigating the performance of a micro-scale, solar thermal Rankine cycle with direct steam generation using an affordable solar collector design. The intended power generation range is between 0.1 and 1 kW, which can be used for the direct mechanical pumping of rural irrigation systems or municipal water supplies. The study focuses on the performance of the solar collector (the solar reflector and the solar receiver) under realistic solar thermal conditions in sub-Saharan Africa, as it is considered to be one of the most important components in the solar thermal Rankine cycle. The performance of the solar collector was first characterised in an optical analysis of the new faceted dish reflector design, which comprised six Mylar membranes stretched over the elliptical rims of television satellite dishes. The optical analysis was conducted with the main goal of determining how much concentrated solar radiation would intercept the experimental receiver aperture during solar testing. This was determined by measuring the reflectivity of the reflector facets through ultraviolet and visible light (UV-VIS) spectroscopy and producing an intercept factor trend as a function of receiver aperture size through photographic lunar flux mapping. Based on the spectroscopy analysis, the spectral reflectivity of the clean Mylar facets was determined to be 97% for the visible light spectrum. The intercept factor was determined to be 87% for the designed receiver aperture diameter of 135 mm. The thermal testing took place on a clear, sunny day with low wind velocities. The solar collector followed the arc of the sun throughout the day with a 1° tracking error. During the testing, municipal water was passed through the receiver at 0.284 g/s and the temperature and pressure within the receiver were recorded. A 91-minute testing period occurred, where the inlet and outlet process flows obtained relatively constant operating temperatures with the inlet temperature at 54 °C and the outlet temperature at 343 °C. The total solar irradiance dropped from 801 to 705 W/m2 during this testing period. Using a reflector with a total incident area of 2.73 m2, the total radiation intercepted at the aperture dropped from 1 845 to 1 625 W during this period. The total power capture by the working fluid averaged at approximately 861 W and the total rate of heat loss was determined to be between 1 000 and 750 W. An average collector efficiency of 42% and an average receiver efficiency of 49% were determined for the testing period. An analysis of the heat loss showed that approximately 84% of the heat was lost through the aperture, of which, 31% was from reflected radiation. The second-law analysis showed that most of the irreversibility in the solar collector was caused by absorption of the concentrated radiation at the coil surface. This was because of the large temperature difference between the sun and the receiver coils. The experimental thermal analysis highlighted the design challenges of the micro-scale thermal Rankine cycle. However, the analysis showed that a solar collector can be constructed using locally sourced, affordable materials and can be used to produce power at a micro-scale. With appropriate attention given to optimising the collector design and determining the optimum operating conditions of the solar receiver, the power cycle would be able to compete with current technologies to provide decentralised power to communities in need. / Dissertation (MEng)--University of Pretoria, 2019. / Technology Innovation Agency (TIA); National Research Foundation (NRF); Department of Science and Innovation (DSI) / Mechanical and Aeronautical Engineering / MEng (Mechanical) / Unrestricted
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AN AMMONIA-BASED CHEMISORPTION HEAT PUMP FOR COLD CLIMATE: EXPERIMENTS AND MODELING FOR PERFORMANCE ANALYSIS AND DESIGN OPTIMIZATIONZhiyao Yang (9187337) 03 August 2020 (has links)
<p>Space and water heating contribute over 50% of all the residential
building energy consumption and are especially major energy consumers in the
cold climates. Meanwhile, conventional furnaces and boilers with energy
efficiency limited to below 100% dominate the residential heating in the cold
climate, and the electric vapor-compression heat pump capacity and efficiency
decline drastically at low ambient temperatures. Thermally driven ammonia-based
chemical adsorption (chemisorption) heat pump (CSHP) systems utilize the
reversible chemical reaction between the ammonia vapor and solid sorbent to
generate heat pumping effect, which can provide heating with much higher energy
efficiency than existing cold-climate heating technologies. Despite the
significant potential of energy efficiency improvement from existing
technologies, most studies in the literature on chemisorption heat pump systems
focus on adopting the technology for refrigeration and energy storage
applications, with very limited investigations available for using the
technology for producing heating in cold climates. </p>
This thesis study is thus conducted to characterize
the operation behavior and performance of a CSHP system under cold ambient
conditions and further identify optimal design and control for such systems to
achieve high performance. In this study, both experimental and modelling
approaches are pursued to investigate a CSHP heating system from the perspective
of the sorption material using the multiple-stage LiCl-ammonia reactions, to
the novel adsorber component with hybrid heat pipe heat exchanger, and finally
to the performance of the complete heat pump system. The experimental studies
are based on a prototype CSHP system tested to identify the chemical kinetics
of the sorption material, as well as the transient performance of the adsorber
and the system. The calibrated chemical kinetics are then used in the
development of a transient adsorber model to analyze the operation and improve
design of the adsorber. The heating COP of the prototype system was measured to
be 0.75-1.16 under ambient temperatures of 8-20
C. Finally, a dynamic
system model is developed based on the dynamic models of the adsorber and other
components in the system. The system model is validated against the
experimental data and used to analyze the detailed energy flow and operation
dynamic. Based on the inefficiencies revealed by the simulation of the current
prototype system, an improved system design with reduced thermal mass and heat
loss is introduced. Simulation of the improved system results in heating COP of
1.17 to 1.23 under -13.9
C to 8.3
C ambient, respectively.
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Identity-Specific Positive Psychology Intervention for Sexual Minorities: A Randomized Control TrialJob, Sarah 01 May 2021 (has links)
Sexual minorities experience mental and physical health disparities in comparison to heterosexual individuals due to minority stress (Branstrom et al., 2016; Kerridge et al., 2017; Meyer, 2003). Positive psychology interventions have improved mental and physical health (Antoine et al., 2018; Lambert D'raven et al., 2015), and therefore these interventions have potential to address health disparities. The current study tested an identity-specific intervention (n = 30) to a general positive psychology intervention (n = 30) and a control group (n = 30) among sexual minorities. This built on a recent pilot study which tested the efficacy of an identity-specific intervention designed for sexual minorities and showed significant improvements in depressive and anxiety symptoms. Thus, I hypothesized that individuals in intervention conditions would have better mental health, physical health, and substance use outcomes than the control group. Additionally, outcomes of the identity-specific condition were compared to those of the general positive psychology intervention. Participants included 91 sexual minority adults that completed three surveys (baseline, one week after the intervention, one month follow-up) including outcomes measures (depressive symptoms, anxiety symptoms, problematic drinking, problems associated with drug use, well-being, and self-rated health), potential covariates (anticipated stigma, internalized stigma, concealment) and manipulation checks (self-compassion, forgiveness, optimism, coping using humor, social support seeking). Fifty-three participants completed interventions featuring five intervention tasks eliciting self-compassion, optimism, forgiveness, humor, and social support seeking. Analyses included descriptive statistics, bivariate correlations, and multilevel modeling. Compared to the control condition, results showed significantly greater improvements in well-being (b = .40, p = .013), self-rated health (b = -.42, p = .006), and problems associated with drug use (b = -.97, p = .004) among participants in the intervention conditions. No significant differences emerged for depressive symptoms, anxiety symptoms, or problematic drinking. Limitations include lack of power for analyses examining extended follow-up and comparing intervention types, as well as a number of history effects. Despite these limitations, the current study has potential to improve health outcomes and aid clinical practices. More research on positive psychology interventions with sexual minorities is needed.
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A Comparison of Underachievers and Normal Achievers at the Upper-Elementary and Seventh-Grade LevelManning, M. Nephi 01 May 1962 (has links)
That each is born with differing capacities and potentials is self-evident. Both students and teachers should accept as their right and duty the task of bringing to full fruition these latent potentialities.
It is a cause of concern in the nation, among parents and teachers, and in later years among students themselves, that many of our youth fail to achieve that of which they are capable. This is a loss to society and a disappointment to the individual.
The purpose of this study is to add to the growing fund of knowledge concerning factors related to this important area of education and the relationship of these factors to life's fulfillment
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The development and effects of an educational audiovisual presentation on female masturbation upon the attitudes and masturbatory behavior of college femalesHogan, Catherine Ann 01 January 1981 (has links)
The current study was designed: (1) to develop an educational tool on female masturbation capable of reaching a wide audience of women with accurate and complete information on female masturbation; (2) to provide initial validation for the further educational usefulness of this tool and (3) to assess its potential ability for improving overall sexual functioning in women by possibly altering negative attitudes toward masturbation and/or by dis-inhibiting masturbatory behavior.
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Sour Grapes While You're Down and Out: Self-Serving Bias and Applicant Attributions for Test PerformanceMack, Kyle Garret 01 January 2010 (has links)
Recent research has shown that outcome favorability (Ryan & Ployhart, 2000) and perceived performance (Chan, Schmitt, Jennings, Clause, & Delbridge, 1998a) are key determinates of justice judgments, suggesting that self-serving bias is a critical mechanism in the formation of applicant reactions. However, organizational justice theory continues to be the dominant paradigm for understanding applicant reactions. Chan and Schmitt (2004) have suggested a far ranging agenda for research into reactions, which includes considering reactions in a longitudinal framework and considering the natural effect of time on reactions. The current study incorporates these theoretical approaches and addresses these gaps in the research by examining applicant reactions at four time points during and after a selection procedure. This study also uses a multi-dimensional measure of test taking motivation (TTM) based on expectancy theory which enables me to explicate the effect of test performance, expectations, and outcome feedback on each motivational component.
Using a sample of 227 student participants, this study provides evidence that an applicant's expectations regarding the selection outcome and the selection outcome itself have strong effects on fairness perceptions and TTM. Some key findings are the following: I) negative selection decisions and negative expectations tend to reduce fairness perceptions and TTM in applicants, while for the most part, positive expectations and positive selection decisions do little to increase these reactions and 2) valence, or the desire for the job, seems to be the motivational component most affected by the selection procedure. These findings have important implications for future research into applicant reactions.
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