Transient thermomechanical interactions of shaft-bushing pair in bearings - a finite element study

This thesis presents a finite element parametric study of the transient thermomechanical interactions of shaft-bushing pairs in bearings to gain insight into the nature of two categories of failures encountered in practice. The first type of failure deals with occurrence of the so-called thermally induced seizure (TIS) during the start-up period followed by an investigation of TIS due to a transient flow-disturbance. The second part deals with the thermomechanical interactions of pin-bushing assembly under heavy oscillating loads where the failure is by TIS and/or thermal galling. An extensive set of parametric simulations covering a wide range of loads, speeds, operating clearance, bearing dimensions, friction coefficients and thermal expansion coefficients are performed to gain insight into the phenomenon of TIS and thermal galling. A statistical procedure is applied to the simulated results and an appropriate empirical relationship is derived that predicts the time to failure for each category. Good agreement between the empirical and published results attests to the capability of the model and its potential for predicting bearing failure

Cross-language tweet classification using Bing translator

Master of ScienceDepartment of Computing and Information SciencesDoina CarageaSocial media affects our daily lives. It is one of the first sources for finding breaking news. In particular, Twitter is one of the popular social media platforms, with around 330 million monthly users. From local events such as Fake Patty's Day to across the world happenings - Twitter gets there first. During a disaster, tweets can be used to post warnings, status of available medical and food supply, emergency personnel, and updates. Users were practically tweeting about the Hurricane Sandy, despite lack of network during the storm. Analysis of these tweets can help monitor the disaster, plan and manage the crisis, and aid in research. In this research, we use the publicly available tweets posted during several disasters and identify the relevant tweets. As the languages in the datasets are different, Bing translation API has been used to detect and translate the tweets. The translations are then, used as training datasets for supervised machine learning algorithms. Supervised learning is the process of learning from a labeled training dataset. This learned classifier can then be used to predict the correct output for any valid input. When trained to more observations, the algorithm improves its predictive performance

Graph splicing systems

AbstractIn this paper, extended graph splicing systems are defined. It is shown that when strings are represented as linear graphs, any recursively enumerable set can be generated by an extended graph splicing system. It is also shown that the computational completeness of extended graph splicing systems can be proved under some constraints too

Specification of Synchronizing Processes

The formalism of temporal logic has been suggested to be an appropriate tool for expressing the semantics of concurrent programs. This paper is concerned with the application of temporal logic to the specification of factors affecting the synchronization of concurrent processes. Towards this end, we first introduce a model for synchronization and axiomatize its behavior. SYSL, a very high-level language for specifying synchronization properties, is then described. It is designed using the primitives of temporal logic and features constructs to express properties that affect synchronization in a fairly natural and modular fashion. Since the statements in the language have intuitive interpretations, specifications are humanly readable. In addition, since they possess appropriate formal semantics, unambiguous specifications result

Specifying and Proving Properties of Sentinels

This paper presents a technique for specifying and verifying properties of sentinels, a high-level language construct for synchronizing access to shared resources. Statements in the specification language possess formal temporal semantics. As a prelude to proving the correctness of sentinels, the semantics of constructs used in sentinels is given. The proof technique involves showing that the temporal behavior of a sentinel conforms to that defined by the specification. The methodology is illustrated by applying it to a typical synchronization problem