629 research outputs found

    An experimental and computational investigation of rotating flexible shaft system dynamics in rotary drilling assemblies for down hole drilling vibration mitigation

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    Rotary drilling system vibration has long been associated with damaging the bit, the bottom hole assembly (BHA) and drill string. Vibration has been traditionally measured in the bottom hole assembly, and been closely associated with the resonant behaviors. This research study proposes an improved physical laboratory model to explore the dynamic behaviors associated with vibration. This model includes contact with the borehole wall allowing a range of stabilization geometries while removing bit-formation interaction effects. The results of exercising the model help develop new insights into both vibration measurement diagnostics and mitigation strategy execution. Presented here is a review of other physical bottom hole assembly and drilling concepts, and a new novel model. Experimental investigation using the new model for a range of geometries is presented with recorded conditions, annotated video stills and analysis using regression and response surface methods. The analysis when compared to existing industry mitigation methods allows unique insight to the possible effectiveness of such methods. A numerical simulation of the system was also performed and its results compared to the laboratory tests. Results show that a shaft system alone can generate stick-slip and whirl behaviors. Such behaviors occur in distinct regions. Another conclusion of this work is that a popular method for inferring stick-slip from acceleration measures is not reliable for the system used in this study

    The change in the order of catalytic action of lithium chloride, sodium chloride, magnesium chloride, and calcium chloride in the ketonic splitting of ethyl acetoacetate

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    The catalytic action of neutral salts on many reactions has been investigated under various conditions, and a large number of explanations have been put forward. In this work the catalytic action of normal solutions of lithium chloride, sodium chloride, magnesium chloride, and calcium chloride in the presence of .1 N. hydrochloric acid on the ketonic splitting of ethyl acetoacetate has been investigated at several temperatures between 80⁰C. and 95⁰C. An attempt has been made to explain the results obtained --Introduction, page 1

    A microcomputer-based network optimization package

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    An important branch of mathematical programming in concerned with optimization in systems described by networks. This paper describes an integrated suite of advanced techniques for dealing with minimum cost network flow formulations. Written in Pascal and implemented on a microcomputer representative of current small computer technology (the Apple II), this package places unprecedented modeling versatility and solution capability on the analyst's desktop. Able to solve small to medium size problems (3000 arcs or less) at reasonable speeds, programs to handle capacitated linear, nonlinear (convex separable), mixed integer and elastic ranged linear models in addition to comprehensive control and data management routines are included. Problem size and solution speed benchmarks are given for a variety of models.http://archive.org/details/microcomputerbas00duffMajor, United States Marine CorpsApproved for public release; distribution is unlimited

    Adam Smith and the theory of punishment

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    A distinctive theory of punishment plays a central role in Smith's moral and legal theory. According to this theory, we regard the punishment of a crime as deserved only to the extent that an impartial spectator would go along with the actual or supposed resentment of the victim. The first part of this paper argues that Smith's theory deserves serious consideration and relates it to other theories such as utilitarianism and more orthodox forms of retributivism. The second part considers the objection that, because Smith's theory implies that punishment is justified only when there is some person or persons who is the victim of the crime, it cannot explain the many cases where punishment is imposed purely for the public good. It is argued that Smith's theory could be extended to cover such cases. The third part defends Smith's theory against the objection that, because it relies on our natural feelings, it cannot provide an adequate moral justification of punishment

    Senecavirus A in Pigs, United States, 2015

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    Citation: Hause, B. M., Myers, O., Duff, J., & Hesse, R. A. (2016). Senecavirus A in Pigs, United States, 2015. Emerging Infectious Diseases, 22(7), 1323-1325. doi:10.3201/eid2207.151951Senecavirus A (SVA) has been sporadically identified in pigs with idiopathic vesicular disease in the United States and Canada (1–3). Clinical symptoms observed include ruptured vesicles and erosions on the snout and lameness associated with broken vesicles along the coronary band. A recent report characterized SVA in pigs in Brazil with similar clinical symptoms in addition to a higher proportion of deaths than would be expected in pigs 1–4 days of age (4,5). Several outbreaks of this infection in pigs were reported in the summer of 2015 in the United States; the more severe clinical features resembled those seen in outbreaks in Brazil (6). Subsequent testing by PCR of 2,033 oral fluid samples from material submitted during 441 routine diagnostic testing procedures (from 25 states) identified 5 SVA-positive cases (1%) (7). Besides affecting animal health, SVA infection is notable because its clinical symptoms resemble those caused by foot-and-mouth disease and vesicular stomatitis viruses. When vesicular disease is observed in US swine, mandatory reporting and testing of animals for foreign animal diseases are required

    Spline analysis of Hydrographic data

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    AbstractThe basic problem involved in determining where the ship can not go is an attempt to reconstruct the sea bed. The interpolation of points necessary to reconstruct the sea bed was done using a bicubic spline. This method was chosen because of the similarities between the boundary conditions believed to be characteristic of the modeling problem and those of the natural spline. These include the continuity of the first and second derivatives, and the minimum curvature exhibited by the spline method which is characteristic of the sea bottom. The major problem faced in modeling the sea bed was selecting the extra data points needed in order to find a meaningful solution. This selection was done both by intuition and by constructing splines to model the possible behavior along a straight line. The results were two different models: a ridge model, characterized by a single shallow ridge in the center of the region; and a hill model, characterized by two smaller ridges. By varying one of these extra data points (called critical points), several models of both these extremes as well as intermediate models were generated. However, it was found that the number of given points did not permit a definitive model. Data was needed inside the region, especially at the critical points and at the exterior points in order to better define the boundary. The boundary could not be reliably determined since our spline model does not allow for accurate extrapolation. Thus, the model, although close to what is believed to be the correct model, is not good enough to allow for navigation because of the limited number of given data points

    Leptin in Teleost Fishes: An Argument for Comparative Study

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    All organisms face tradeoffs with regard to how limited energy resources should be invested. When is it most favorable to grow, to reproduce, how much lipid should be allocated to storage in preparation for a period of limited resources (e.g., winter), instead of being used for growth or maturation? These are a few of the high consequence fitness “decisions” that represent the balance between energy acquisition and allocation. Indeed, for animals to make favorable decisions about when to grow, eat, or reproduce, they must integrate signals among the systems responsible for energy acquisition, storage, and demand. We make the argument that leptin signaling is a likely candidate for an integrating system. Great progress has been made understanding the leptin system in mammals, however our understanding in fishes has been hampered by difficulty in cloning fish orthologs of mammalian proteins and (we assert), underutilization of the comparative approach

    Reflecting on researcher practice relationships in prison research : A contact hypothesis lens

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    Interactions between researchers and professionals need to be carefully managed in the criminal justice context. This chapter explores the utility of the theoretical lens of the contact hypothesis as a means to understand and improve these relations. The COLAB consortium is used as a case study of a typical partnership between professionals in practice and researchers in academia to illustrate this. We use the reflections of four of its members from both professional and researcher European institutions to explore how the conditions of contact proposed by the contact hypothesis may have impacted on the experiences of participants. Strategies through which these relations can be optimised in the interest of prison research, but also the care and management of people in contact with the criminal justice system, are proposed.publishedVersio
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