15,657 research outputs found
Free-convection condensation on single horizontal pin-fin tubes
No full textPhDNew experimental data are reported for free-convection condensation of ethylene
glycol and R-113 on three-dimensional pin-fin tubes. Effects of pin geometry and tube
thermal conductivity (for copper, brass and bronze giving a mean range of 400, 120 and
80 W/m K over the range of temperature of interest) were investigated. All tests were
performed at near atmospheric pressure with downward flowing vapour at low velocity.
Heat-transfer enhancement was found to be approximately twice the corresponding
active surface area of the tubes, i.e. the surface area of the parts of the tube and pin
surface not covered by condensate retained by surface tension. For ethylene glycol, the
best performing pin-fin tube gave a heat-transfer enhancement of 5.8, about 24 %
higher than the ‘equivalent’ two-dimensional integral-fin tube (i.e. with the same finroot
diameter, longitudinal fin spacing and thickness and fin height). For R-113, the
best enhancement was 5.9, about 10 % higher than the equivalent integral-fin tube.
For both fluids tested, vapour-side, heat-transfer enhancement was found to increase
with decreasing circumferential pin spacing and increasing pin height. Circumferential
pin thickness had little effect on heat-transfer enhancement. Effects of tube thermal
conductivity were found to be more significant for ethylene glycol than R-113.
Retention angle measurements were made under static conditions (without
condensation) and were found to be larger than for equivalent integral-fin tubes. An
expression for condensate retention angle on pin-fin tubes was proposed and found to
agree with the measured retention angles to ±15%.
A semi-empirical model for condensation heat transfer on horizontal pin-fin tubes has
been developed which accounts for the combined effect of gravity and surface tension.
The model predicts the majority of available data to ±20 %
ZONG-WEI ZHU, XIN-GUI LE, LU-FEI LI, SHI-PIN CHEN & BIN CHEN (2023) Sedum yangjifengensis (Crassulaceae), a new species from Jiangxi, China. Phytotaxa 607 (1): 105-113
No full textZong-Wei Zhu, Xin-Gui Le, Lu-Fei Li, Shi-Pin Chen (2023): ZONG-WEI ZHU, XIN-GUI LE, LU-FEI LI, SHI-PIN CHEN & BIN CHEN (2023) Sedum yangjifengensis (Crassulaceae), a new species from Jiangxi, China. Phytotaxa 607 (1): 105-113. Phytotaxa 607 (4): 261-261, DOI: https://doi.org/10.11646/phytotaxa.607.4.5, URL: http://dx.doi.org/10.11646/phytotaxa.607.4.
Pin-Chun Chen Cello Recital Program Notes
No full textThis report discusses the works of four Russian composers spanning from the early to the late nineteenth century. The early nineteenth century pieces include Pyotr Tchaikovsky\ue2s Nocturne Op. 19, No. 4, and Pezzo Capriccioso Op. 62, as well as Sergey Rachmaninoff\ue2s Pr\uc3\ua9lude et Danse Orientale Op. 2. The end of the nineteenth century pieces are Dmitri Shostakovich\ue2s The Second Waltz from Suite for Variety Orchestra Op. 99, and Nikolai Myaskovsky\ue2s Sonata for Cello and Piano Op. 81.
Tchaikovsky and Rachmaninoff\ue2s pieces mentioned above are both originally written for piano and was later transcribed for well-known cellist Anatoly Brandukov (1859-1930). Myaskocsky\ue2s cello sonata and Shostakovich\ue2s \ue2Waltz No. 2\ue2 were composed under the pressure of the Russian government. Although these four works were completed under different circumstances and political factors, the Rusiian style remained evident. I will introduce the background of these works of their style, and their interpretation
[Ping Lao She zuo pin]. 3
No full text[陳大鵬].Title and author supplied by cataloguer.Live recording.Electronic reproduction from Rulan Chao Pian Audio Cassette Collection.Spoken in Chinese.[Chen Dapeng]
Design of a scrutable learning system
No full textPersonal Learning Environments (PLEs) refer to systems that allow individual learners to manage and control their own learning in their own space and at their own pace. In this work we explore the different ways in which a learning experience can be informal, and propose a 4D model of informal learning to characterise the informal aspects of a learning experience.The model includes dimensions for learning objectives, the learning environment, learning activities and learning tools, and reveals how much of the experience is really under the control of the learner. In an analysis of mobile tools presented in the mLearn 2008 conference we show that many emerging m-learning systems focused on informality in the environment dimension but not in the others.To solve this problem this report proposes a scrutable learning model approach that allows personal learners to take control of their learning objectives while still allowing the system to intelligently support them with appropriate learning activities and resources. In addition an experimental design is described based around a prototype of a scrutable learning system for mobile devices
Limitations of Push-out Test in Bond Strength Measurement
No full textIntroduction: The push-out test has been widely performed to measure the bond strength of intracanal materials in dentistry. However, it is difficult to compare equitably the bond strengths from different testing specimens. The aim of this study was to investigate how a specimen's geometric parameters and the elastic moduli of dentin and intracanal filling materials may affect the bond strength measurement. Methods: Finite element analysis was used to simulate a push-out test. A base model was established, and 3 parameters were modified: the diameter of the pin, the specimen's thickness, and the elastic modulus of the intracanal filler. The analytic stress results and the calculated bond strengths derived from the original formula for the push-out test were compared at the interfaces. Results: Specifically, the following observations were made: the interfacial stress distributions are mostly unaffected when the ratio of the pin diameter to the specimen's diameter is less than 0.85, and the ratio of the specimen's thickness to the specimen's diameter is greater than 0.6. Two correction factors were suggested for fillers with diverse elastic moduli with respect to the dentin modulus. Two modified formulas for the push-out bond strength test for the test specimens using different bonded composite materials were proposed. Conclusions: The results showed that geometric parameters and materials have certain effects on the push-out bond strength. A more rigorous standard for the push-out test can be established for future applications. (J Endod 2013;39:283 287
Zhili sheng shang pin chen lie suo di yi ci diao cha shi ye bao gao shu /
No full textImprint date from preface.Mode of access: Internet
Social cognitive and neural mechanisms of food choice under the influence of food-related information
No full textFood is the fuel of life. As such food stimuli are intensively processed by the human brain and the consequences of these processes, resulting in our food choice, have an essential impact on our life. Research suggested that food choice is largely guided by predominantly learned preference, and is likely to be influenced by information regarding the food (e.g., nutritional value) as well as by learned beliefs and associations (e.g., between a given food and its health value). This project aims at understanding at both behavioral and neural levels how these non-physiological factors might influence the food/drink choice and how they can be modified to improve our choice.
Chapter 1 includes the literature review on 1) how semantic information influences implicit/explicit associations toward food/drink, 2) the predictive validity implicit/explicit associations on food/drink choice, 3) the behavioral and neural evidence of changing associations, choices, and impulsivity control toward food/drink by implementing a conditioning paradigm (e.g. evaluative conditioning). The motivation and the objectives of my Ph.D. project are also presented here.
Chapter 2 contains Study 1 (Experiment 1 and 2). The first aim of the thesis is to understand how the association between a certain food and different concepts may guide our choices. This is addressed in Experiment 1 where I investigated how our choices can be predicted by preference and/or implicit associations between different constructs of interest (e.g., social status) and coffee and/or tea. People’s self-report preference, implicit and explicit associations between different social constructs and tea/coffee were measured. Results based on 22 Italian healthy adults indicate that they possess strong implicit associations between tea and low social status, and this association significantly predicted choice of tea. The second aim of the thesis is to investigate whether the associations between food/drink and certain constructs can be changed through a classical learning paradigm, evaluative conditioning (EC), in which the associations between target drinks/food and food-related information was manipulated. This approach allowed us to investigate a possible strategy of intervention that could improve drink/food choices. This is addressed in Experiment 2 whereby a within-subject design is employed with participants going through both EC-condition and control condition. Results based on 68 healthy adults show that the implicit associations between tea and high-social-status, as well as the preference towards tea, significantly increase after EC. Most importantly, the difference in implicit associations across conditions significantly predict the difference in choices of tea between conditions, indicating that changes in implicit associations determine changes in choice.
Chapter 3 is dedicated to the third aim which is to identify the neural mechanisms underlying the changes in association after EC between foods and the concepts of healthiness and sustainability. To this end changes in neural markers were related to changes in food choice as well as personal eating habits and individual difference in restraint eating and impulsive behavior. In Study 2, I experimentally strengthened the association between the concept of unhealthiness/unsustainability and heavily-processed food, and between healthiness/sustainability and minimally-processed food. A semantic congruency task combined with the Electroencephalography (EEG) technique was used to investigate changes in neural activity of the N400 in incongruent trials. Results on 18 healthy adults derived by comparing neural signatures of incongruent trials between conditions demonstrated that the magnitude of the N400 in left dorsal lateral prefrontal cortex (DLPFC) for minimally-processed high-calorie food significantly increased after EC. Thus, EC can be considered as an effective method to strengthen the semantic association between foods and a given concept, indexed by the change of neural signature tracking the semantic conflict. This increased magnitude also positively correlated with the Barratt Impulsiveness Scale score, indicating that the more impulsive a person is, the greater the change in magnitude of the N400.
Chapter 4 is devoted to address the fourth aim of the thesis that is to understand whether control of impulsivity over unhealthy food choice can be improved through the evaluative priming (EP) that is a variation of EC used in Study 2. Thus in Study 3, 15 healthy adults went through a pre-EP and a post-EP test including a Go/NoGo task combined with EEG. During EP, an increased subjective liking was found for Minimally-Processed Low-Calorie food images in evaluative block. For GNG tasks, at neural level, the averaged amplitude at left DLPFC for food images with evaluative priming was more negative in post-EP than in pre-EP GNG task. More negative N200 amplitudes were consistently found at left DLPFC in post-EP GNG task for Heavily-Processed Low-Calorie food as well as for Minimally-Processed Low-Calorie food. The behavioral and neural evidence showed the improvement of self-control towards food stimuli through evaluative priming. The possible role of left dorsal lateral prefrontal region in online value modulation and in integrating the stimulus feature with related information was identified, suggesting the self-control process based on deliberated thinking with symbolic representations and information operations.
In Chapter 5 I summarized and discussed the main findings of my thesis. In short, my project provides the basic roadmap for understanding how food/drink related information affects cognitive and neural underpinnings of food/drink choices. Indeed, choices can be improved through modifying associations between food/drink and related information and thus healthy diets are encouraged. These results provide a potentially interesting research avenue well as possible interventions to modify and improve food/drink choices that could possibly be applied to individuals with eating disorders
The effect of orientation and shape distribution of gravel on slope angles in central Taiwan
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