3,972 research outputs found

    Meteoroid detector

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    A meteoroid detector is described which uses, a cold cathode discharge tube with a gas-pressurized cell in space for recording a meteoroid puncture of the cell and for determining the size of the puncture

    Doing evolution in economic geography

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    Evolutionary approaches in economic geography face questions about the relationships between their concepts, theories, methods, politics, and policy implications. Amidst the growing but unsettled consensus that evolutionary approaches should employ plural methodologies, the aims here are, first, to identify some of the difficult issues confronting those working with different frameworks. The concerns comprise specifying and connecting research objects, subjects, and levels; handling agency and context; engaging and integrating the quantitative and the qualitative; comparing cases; and, considering politics, policy, and praxis. Second, the purpose is to articulate a distinctive geographical political economy approach, methods, and illustrative examples in addressing these issues. Bringing different views of evolution in economic geography into dialogue and disagreement renders methodological pluralism a means toward improved understanding and explanation rather than an end in itself. Confronting such thorny matters needs to be embedded in our research practices and supported by greater openness; more and better substantiation of our conceptual, theoretical, and empirical claims; enhanced critical reflection; and deeper engagement with politics, policy, and praxis

    A low cost cell calibration technique and its PC based control software

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    In this study, a technique will be presented to measure the absolute position of a robot and any other strategic positions within the workcell, and also its specially built control software. One of the most important factors affecting the absolute or world accuracy of robots is the variation in arm geometry from a perfect kinematics form. Since arm position is essentially controlled by means of joint angles, Cartesian co-ordinates of the tool centre point are derived from the forward kinematics transform equations assuming a perfect kinematics form. Any deviation from this perfect case will result in world positional errors and hence, for effective off-line programming it is important to calibrate the real robot hardware against the virtual model used by the robot simulation computer systems. This paper will report on work carried out in developing such low cost calibration technique, its PC Based control software and performance monitoring systems

    Automation of beam straightness measurement

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    This work deals with the development of an image processing methodology to be employed in an inspection machine for measurement of straightness of moving steel beams. The method consists of developing specific software to perform three main tasks: reading the position of the beam at several locations; correlating the data monitored by the cameras; and reporting the quality of the beam straightness. Computer vision technology as a non contact measuring system is used by the inspection machine. From the production process the beams roll onto a conveyor therefore several video cameras are needed to log information about the lateral position and also the height of the steel beams. The number of cameras and the distance between them can be defined by the user. The technique is developed in such a way that if one camera fails or is switched off the measuring system is not affected as long as the system has a minimum of three cameras viewing acceptable points. The system outputs is the deviations from a perfectly straight beam; compensating factors for lateral or angular movements in the horizontal measuring plane of the beam and the beam profile. The output is displayed on a computer screen, and is based on both linear and least squares curve fitting routines

    Cell calibration and robot tracking

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    When considering off-line programming of Industrial robots, it is important that the simulated model of the robot and its environment is calibrated against the real hardware. It is well known that industrial robots have relatively good position repeatability characteristics but suffer from a lack of precision in terms of absolute accuracy. When programmed on-line, this is not apparent since the programmer intuitively moves the robot to location points which are relative to the workpiece and other elements within the cell. However, when considering off-line programming using simulation software to represent the robot and its environment, the absolute accuracy of the system becomes a critical issue. The effectiveness of off-line programming is only apparent if there is a true correspondence between the “virtual” simulation system and the “real” hardware system. In order to provide cell calibration, it is important to be able to measure the absolute position of the robot and other strategic locations within the cell. This paper presents details of a measuring system for recording tool point absolute positions and path trajectories. It is intended that this data is then used to improve the correlation between the simulated and the real kinematics of the robot cell

    Spectral radiometry and tropospheric aerosols: Report of panel

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    The term aerosols, as used here, refers to the haze, smoke, and dust that appear in the troposphere. The term does not refer to the hydrometeors in cumulus and stratus clouds but does include the sulfuric acid-water droplets which are assumed to predominate in the stratospheric aerosol layer. The aerosol properties that were measured from satellites and those which can be made in the near term (up to 1992) will be reviewed. The capabilities that will exist in the years 1992 to 2000, with implementation of EOS, are then discussed. Finally, a few words will be said concerning the potential for aerosol measurements for the decade after 2000

    Practical case of rapid prototyping using gas metal arc welding

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    To prove the viability of ‘Rapid Prototyping using Fusion Welding’ the author presents an example of a component created using this process. At this stage of the work, the process is not yet completed thus some of the modules that are part of this process were generated artificially. This paper will present the following sections: 1) a basic idea of how the process works, 2) description of each step in the process, 3) software/hardware used, 4) how each module was performed on the creation of this example, 5) the resultant shape and values, 6) deviations from the planned shape and 7) some conclusions

    Where is the USA Corn Belt, and how is it changing?

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    The “Corn Belt” is a commonly used term, but often referenced as a vaguely defined region in the Midwest USA. A few key studies have delineated synoptic maps of the Corn Belt boundaries going back to the early 20th century, but a modern flexible and accessible framework for mapping the Corn Belt in space and time is needed. New tools provide reference maps for the Corn Belt in the 21st century and the ability to quantify space-time changes in corn cropping patterns. The Land use and Agricultural Management Practices web-Service (LAMPS) was used to estimate the average corn (maize, Zea mays L.) area in each county of the contiguous 48 USA states for the years 2010–2016. LAMPS provides a modified areal Fraction of corn (Fc) used to map the Corn Belt at three intensity levels, for example. The resulting patterns illustrate a mostly contiguous Midwest Corn Belt surrounded by more scattered regions, including southern and eastern regions. We also mapped irrigated areas and temporal changes in Fc. Mapped patterns have the potential to help researchers study issues related to food, feed, biofuel, and water security

    Real-time analysis of gene regulation by glucocorticoid hormones

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    There is increasing evidence that temporal factors are important in allowing cells to gain additional information from external factors, such as hormones and cytokines. We sought to discover how cell responses to glucocorticoids develop over time, and how the response kinetics vary according to ligand structure and concentration, and hence have developed a continuous gene transcription measurement system, based on an interleukin-6 (IL-6) luciferase reporter gene. We measured the time to maximal response, maximal response and integrated response, and have compared these results with a conventional, end point glucocorticoid bioassay. We studied natural glucocorticoids (corticosterone and cortisol), synthetic glucocorticoids (dexamethasone) and glucocorticoid precursors with weak, or absent bioactivity. We found a close correlation between half maximal effective concentration (EC50) for maximal response, and for integrated response, but with consistently higher EC50 for the latter. There was no relation between the concentration of ligand and the time to maximal response. A comparison between conventional end point assays and real-time measurement showed similar effects for dexamethasone and hydrocortisone, with a less effective inhibition of IL-6 seen with corticosterone. We profiled the activity of precursor steroids, and found pregnenolone, progesterone, 21-hydroxyprogesterone and 17-hydroxyprogesterone all to be ineffective in the real-time assay, but in contrast, progesterone and 21-hydroxyprogesterone showed an IL-6 inhibitory activity in the end point assay. Taken together, our data show how ligand concentration can alter the amplitude of glucocorticoid response, and also that a comparison between real-time and end point assays reveals an unexpected diversity of the function of glucocorticoid precursor steroids, with implications for human disorders associated with their overproduction

    Near-Infrared Polarimetric Adaptive Optics Observations of NGC 1068: A torus created by a hydromagnetic outflow wind

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    We present J' and K' imaging linear polarimetric adaptive optics observations of NGC 1068 using MMT-Pol on the 6.5-m MMT. These observations allow us to study the torus from a magnetohydrodynamical (MHD) framework. In a 0.5" (30 pc) aperture at K', we find that polarisation arising from the passage of radiation from the inner edge of the torus through magnetically aligned dust grains in the clumps is the dominant polarisation mechanism, with an intrinsic polarisation of 7.0%±\pm2.2%. This result yields a torus magnetic field strength in the range of 4-82 mG through paramagnetic alignment, and 13920+11^{+11}_{-20} mG through the Chandrasekhar-Fermi method. The measured position angle (P.A.) of polarisation at K' is found to be similar to the P.A. of the obscuring dusty component at few parsec scales using infrared interferometric techniques. We show that the constant component of the magnetic field is responsible for the alignment of the dust grains, and aligned with the torus axis onto the plane of the sky. Adopting this magnetic field configuration and the physical conditions of the clumps in the MHD outflow wind model, we estimate a mass outflow rate \le0.17 M_{\odot} yr1^{-1} at 0.4 pc from the central engine for those clumps showing near-infrared dichroism. The models used were able to create the torus in a timescale of \geq105^{5} yr with a rotational velocity of \leq1228 km s1^{-1} at 0.4 pc. We conclude that the evolution, morphology and kinematics of the torus in NGC 1068 can be explained within a MHD framework.Comment: 14 pages, 4 figures, Accepted by MNRA
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