Online Bearing Remaining Useful Life Prediction Based on a Novel Degradation Indicator and Convolutional Neural Networks

In industrial applications, nearly half the failures of motors are caused by the degradation of rolling element bearings (REBs). Therefore, accurately estimating the remaining useful life (RUL) for REBs are of crucial importance to ensure the reliability and safety of mechanical systems. To tackle this challenge, model-based approaches are often limited by the complexity of mathematical modeling. Conventional data-driven approaches, on the other hand, require massive efforts to extract the degradation features and construct health index. In this paper, a novel online data-driven framework is proposed to exploit the adoption of deep convolutional neural networks (CNN) in predicting the RUL of bearings. More concretely, the raw vibrations of training bearings are first processed using the Hilbert-Huang transform (HHT) and a novel nonlinear degradation indicator is constructed as the label for learning. The CNN is then employed to identify the hidden pattern between the extracted degradation indicator and the vibration of training bearings, which makes it possible to estimate the degradation of the test bearings automatically. Finally, testing bearings' RULs are predicted by using a $\epsilon$-support vector regression model. The superior performance of the proposed RUL estimation framework, compared with the state-of-the-art approaches, is demonstrated through the experimental results. The generality of the proposed CNN model is also validated by transferring to bearings undergoing different operating conditions

Magnetic perturbations due to current structural variations

Study of the magnetic perturbations caused by auroral currents has been conducted by rocket-borne magnetometer measurements for years. Since the horizontal auroral currents were usually found to be confined near the visible auroral arcs, as determined by Heppner [1954], Davis [1961], and Davis and Kimball [1962], a number of current models have been established in order to explain observed data by rockets or satellite measurements. In those models, the requirement that the current be continuous across the highly conducting arc results in either polarization electric fields to reduce the current in the highly conducting region or Birkeland currents to provide return current to the outer part of the magnetosphere. Bostrom found two basic solutions, one in which a horizontal electrojet connects two filamentary Birkeland currents, and the other in which broad Birkeland sheet currents (Fig. 2) flow to the edges of the arc, with a transverse closing current and a Hall electrojet. In this thesis, we adopted a model similar to the second solution and assumed that the arc was bombarded by energetic precipitating electrons. In this thesis, the effect of a spatial fold on the magnetic vector field in the vicinity of the arc is examined. Fig. 1 shows the current model used in the initial calculations. It has a displacement of thickness of 3 km from its center and is composed of two current parts. One part is the two oppositely directed Birkeland sheet currents having an equal current density of .5 amp/m and an equal thickness of 3 km for each sheet, in which the downward current sheet is on the south side of the arc and the upward on the north. And the 3 other part is an electrojet having a magnitude of 5 x 1 amp flowing eastward at an altitude of 1 km. Model computations were performed with the Rice IBM 37/155 computer. The variations of the vector components as well as the directions of the magnetic fields due to the following three cases, such as the electrojet, the sheet currents and the combination of the two along a path of rocket flight were individually included in details. For the electrojet current which was a kinked line current at the center, we get more details from a comparison with a straight line current in Chapter 2

Removal Of Volatile Organic Compound (Voc) From Air Using Zeolite Based Adsorption-Catalytic Combustion System [TD885.5.R46 W872 2007 f rb].

Pembangunan kaedah termaju dalam proses penyingkiran sebatian organic meruap (VOC) yang terdiri daripada unit penjerapan diikuti oleh unit pembakaran bermangkin telah dicadangkan dalam kajian ini. The development of an advanced VOC destruction process consists of an adsorption unit followed by a catalytic combustion system has been proposed in the current study

Market Movement, Earning Capacity and Asset Fluctuation in Taiwanese Stock Exchange

This study examines a simple theory in which investors with market movement behaviours to show the influence of market movement on the relation between earning capacities, returns, and return volatility, and then we examine the empirical evidences from our theory. It first illustrates how asset fluctuation may fluctuate more than the fundamental valu

The Eisenhower administration and U.S. foreign and economic policy towards Latin America from 1953 to 1961

The thesis aims to examine Eisenhower’s foreign policy towards Latin America from 1953 to 1961. In order to win the Cold War, the leading bureaucrats were split over different approaches needed to achieve policy objectives in Latin America within the hierarchically regularized machinery- but it was not necessarily welcomed by every Latin American nation. There were three problems with Eisenhower’s staff structuring arrangement towards Latin America: (a) politicization of U.S.-Latin American relations from 1953 to 1961 by senior U.S. bureaucrats with an anti-communism agenda for Latin American development; (b) neglect of Latin American requests for public funds before 1959; (c) bureaucratic conflicts over different methods to achieve foreign policy objectives, often resulting in tensions between policy and operations. The bureaucratic approach limited U.S. understanding of Latin America, meaning (a) the National Security Council (NSC) advisory system could not meet stated ideals; (b) the American approach had limited applicability to Latin American societies; (c) tensions existed between U.S. ideals and political, economic and social realities in Latin American countries. By examining the Foreign Relations of the United States volumes and Latin American literature, this thesis moves beyond the existing scholarship of U.S.-Latin American relations and provides a new appraisal of Eisenhower’s approach towards Latin America in the Cold War context

Texture of light in environmental theatre : Elvis Machine

This thesis explores the varied ways in which texture from light is created through the use of sculpted materials and objects for use in environmental theatre. Shadow, silhouette and reflection are created through the use of both light and object from light but through objects. The objects, made from varied materials, determine not only the quality of light but also the quality of the textures projected. For the performing arts, lighting designers create light to speak a magical language. This language moves to tell the same story as that of the performers and of all other invested collaborators. However, light would not be seen without objects that reflect it. Performers, scenery, and costumes are objects that can tell and support the story and also serve as surfaces and objects ready to accept and reflect lighting texture. It is the materiality of an object that determines the quality of texture. In this case, materials of the medium are going to be storytellers in costume using crafted objects on a stage located in an open-air parking lot under the natural sky. Unlike the methods of lighting for the traditional theatre, I am going to experiment with materials and create the texture of light by using non-theatrical instruments for the collaborative performance of Elvis Machine created by The Duplicates Theatre Company. These non-theatrical instruments, also known as practical lighting, will serve as the primary sources for light and for texture. The purpose of creating the texture with practical lighting for this performance is to explore the way in which we use the texture in environmental theatre. It is common practice for theatrical lighting designers to create texture for the stage through the use of pre-manufactured lighting templates. The basic constructs of environmental theatre, in the case of Elvis Machine located in an open-air lot, makes it difficult if not nearly impossible to employ the use of theatrical instrumentation as the primary source of light and texture. My solution for the production of Elvis Machine is to design and to create all of the necessary lighting fixtures required for the production.Theatre and Danc