Vapor phase clustering model for water

Although nucleation phenomena are among the most widespread of all naturally occurring phenomena, even the simplest of nucleation processes, homogeneous nucleation, is poorly understood, particularly the homogeneous nucleation of liquid droplets from water vapor. Homogeneous nucleation involves only molecules of a single substance and does not include the complicating effects due to a substrate or piece of foreign matter. The semiphenomenological liquid drop theories developed nearly three decades ago differ in relatively minor details, with the crucial element of the theory being the derivation of the free energy of formation of the clusters. The clusters are viewed as well-defined incompressible spherical droplets which possess bulk properties. Such considerations do not take into account the details of the transition region at the interface between the two phases. Recent quantum statistical corrections to the theory are merely attempts to formulate a hybrid theory containing both bulk thermodynamic and quantum statistical considerations...In this dissertation, a statistical mechanical technique is developed from which the equilibrium concentrations of clusters of various sizes may be calculated if the bonding structure of the clusters can be predicted and the energy associated with the various structures are known --Abstract, page ii-iii

An Assessment of Economic Analysis Methods for Cogeneration Systems

Cogeneration feasibility studies were conducted for eleven state agencies of Texas. A net present value (NPV) analysis was used to evaluate candidate cogeneration systems and select the optimum system. CELCAP, an hour-by-hour cogeneration analysis computer program was used to determine the costs used in the NPV analysis. The results of the studies showed that the state could save over $6,000,000 per year in reduced utility bills. Different methods of analyzing the economic performance of a cogeneration system are presented for comparison. Other implications of the study are also discussed

CDIO Projects in DTU’s B.Eng. in IT Study Program

Since the fall 2008 all B.Eng. study programs at the Technical University of Denmark have been based on the CDIO concept. The adoption of the CDIO standards and principles resulted in new or significantly revised study programs. As part of this effort design-build projects have been introduced on each of the first 4 semesters, and each semester-project spans several courses. The aim of this paper is to describe the four CDIO semester projects in the B.Eng. in IT study, and – along with similar papers describing the other six B.Eng. programs – to provide documentation to accompany an exposition with stands providing additional information and with students demonstrating their projects. The paper is narrowly focused on the IT-study program. At the time of writing this paper the students enrolled in 2008 have completed all four semesters in the new CDIO-based study plan, and the students enrolled in 2009 are currently in the process of finishing the 4 th semester. Consequently, the paper is reporting on curriculum development which has been implemented, and for which experiences have gained

Effect of head impacts on diffusivity measures in a cohort of collegiate contact sport athletes

Objective: To determine whether exposure to repetitive head impacts over a single season affects white matter diffusion measures in collegiate contact sport athletes. Methods: A prospective cohort study at a Division I NCAA athletic program of 80 nonconcussed varsity football and ice hockey players who wore instrumented helmets that recorded the acceleration time history of the head following impact, and 79 non–contact sport athletes. Assessment occurred preseason and shortly after the season with diffusion tensor imaging and neurocognitive measures. Results: There was a significant (p 5 0.011) athlete-group difference for mean diffusivity (MD) in the corpus callosum. Postseason fractional anisotropy (FA) differed (p 5 0.001) in the amygdala (0.238 vs 0.233). Measures of head impact exposure correlated with white matter diffusivity measures in several brain regions, including the corpus callosum, amygdala, cerebellar white matter, hippocampus, and thalamus. The magnitude of change in corpus callosum MD postseason was associated with poorer performance on a measure of verbal learning and memory. Conclusion: This study suggests a relationship between head impact exposure, white matter diffusion measures, and cognition over the course of a single season, even in the absence of diagnosed concussion, in a cohort of college athletes. Further work is needed to assess whether such effects are short term or persisten

Accelerated tibial fracture union in the third trimester of pregnancy: a case report

<p>Abstract</p> <p>Introduction</p> <p>We present a case of accelerated tibial fracture union in the third trimester of pregnancy. This is of particular relevance to orthopaedic surgeons, who must be made aware of the potentially accelerated healing response in pregnancy and the requirement for prompt treatment.</p> <p>Case presentation</p> <p>A 40 year old woman at 34 weeks gestational age sustained a displaced fracture of the tibial shaft. This was initially treated conservatively in plaster with view to intra-medullary nailing postpartum. Following an emergency caesarean section, the patient was able to fully weight bear without pain 4 weeks post injury, indicating clinical union. Radiographs demonstrated radiological union with good alignment and abundant callus formation. Fracture union occurred within 4 weeks, less than half the time expected for a conservatively treated tibial shaft fracture.</p> <p>Conclusion</p> <p>Long bone fractures in pregnancy require clear and precise management plans as fracture healing is potentially accelerated. Non-operative treatment is advisable provided satisfactory alignment of the fracture is achieved.</p

Logic, Probability and Action: A Situation Calculus Perspective

The unification of logic and probability is a long-standing concern in AI, and more generally, in the philosophy of science. In essence, logic provides an easy way to specify properties that must hold in every possible world, and probability allows us to further quantify the weight and ratio of the worlds that must satisfy a property. To that end, numerous developments have been undertaken, culminating in proposals such as probabilistic relational models. While this progress has been notable, a general-purpose first-order knowledge representation language to reason about probabilities and dynamics, including in continuous settings, is still to emerge. In this paper, we survey recent results pertaining to the integration of logic, probability and actions in the situation calculus, which is arguably one of the oldest and most well-known formalisms. We then explore reduction theorems and programming interfaces for the language. These results are motivated in the context of cognitive robotics (as envisioned by Reiter and his colleagues) for the sake of concreteness. Overall, the advantage of proving results for such a general language is that it becomes possible to adapt them to any special-purpose fragment, including but not limited to popular probabilistic relational models