297 research outputs found

    A Case Study of Assessing Button Bits Failure through Wavelet Transform Using Rock Drilling Induced Noise Signals

    Get PDF
    Finding the precise moment of button breakage of bits during drilling, with the experience of drill rig operators is a serious concern for modern vibrant mining industry. This research proposed a new methodology to find the failure of button using the sound generated by rock-bit interactions. The experiment is conducted by the video and sound data recorded during a drilling process in an underground mine, that uses a Sandvik AXERA7 twin boom jumbo drill rig and Polycrystalline diamond (PCD) tapered button bits. Signal analysis techniques such as Fourier transform and Wavelet transform are utilised to analyse the hectic noise signal recorded. The analysed results are shown that Wavelet Transform is much more effective in finding singularity points such as chipping or breakage of a button in compared to the Fourier Transform. The outcome of this analysis, which is the peak intensity at the breakage point, was correlated to the average intensity of the sound wave using moving average method. The results suggest that the noise generated during the drilling process can be used to detect the condition of the drill bit

    Simulating Electron Transport and Synchrotron Emission in Radio Galaxies: Shock Acceleration and Synchrotron Aging in Axis-Symmetric Flows

    Get PDF
    We introduce a simple and economical but effective method for including relativistic electron transport in multi-dimensional simulations of radio galaxies. The method is designed to follow explicitly diffusive acceleration at shocks, and, in smooth flows 2nd order Fermi acceleration plus adiabatic and synchrotron cooling. We are able to follow both the spatial and energy distributions of the electrons, so that direct synchrotron emission properties can be modeled in time-dependent flows for the first time. Here we present first results in the form of some axis-symmetric MHD simulations of Mach 20 light jet flows. These show clearly the importance of nonsteady terminal shocks that develop in such flows even when the jet inflow is steady. As a result of this and other consequences of the fundamentally driven character of jets, we find complex patterns of emissivities and synchrotron spectra, including steep spectral gradients in hot spots, islands of distinct spectra electrons within the lobes and spectral gradients coming from the dynamical histories of a given flow element rather than from synchrotron aging of the embedded electrons. In addition, spectral aging in the lobes tends to proceed more slowly than one would estimate from regions of high emissivity.Comment: 30 pages of Latex generated text plus 7 figures in gif format. Accepted for publication in the Astrophysical Journal. High resolution postscript figures available through anonymous ftp at ftp://ftp.msi.umn.edu/pub/users/twj/RGje

    An Earth-sized Planet around an M5 Dwarf Star at 22 pc

    Get PDF
    We report on the discovery of an Earth-sized transiting planet (R p = 1.015 ± 0.051 R ⊕) in a P = 4.02 day orbit around K2-415 (EPIC 211414619), an M5V star at 22 pc. The planet candidate was first identified by analyzing the light-curve data obtained by the K2 mission, and it is here shown to exist in the most recent data from TESS. Combining the light curves with the data secured by our follow-up observations, including high-resolution imaging and near-infrared spectroscopy with IRD, we rule out false-positive scenarios, finding a low false-positive probability of 2 × 10−4. Based on IRD’s radial velocities of K2-415, which were sparsely taken over three years, we obtain a planet mass of 3.0 ± 2.7 M ⊕ (M p < 7.5 M ⊕ at 95% confidence) for K2-415b. Being one of the lowest-mass stars (≈0.16 M ⊙) known to host an Earth-sized transiting planet, K2-415 will be an interesting target for further follow-up observations, including additional radial velocity monitoring and transit spectroscopy

    Bcl-2 protein family: Implications in vascular apoptosis and atherosclerosis

    Get PDF
    Apoptosis has been recognized as a central component in the pathogenesis of atherosclerosis, in addition to the other human pathologies such as cancer and diabetes. The pathophysiology of atherosclerosis is complex, involving both apoptosis and proliferation at different phases of its progression. Oxidative modification of lipids and inflammation differentially regulate the apoptotic and proliferative responses of vascular cells during progression of the atherosclerotic lesion. Bcl-2 proteins act as the major regulators of extrinsic and intrinsic apoptosis signalling pathways and more recently it has become evident that they mediate the apoptotic response of vascular cells in response to oxidation and inflammation either in a provocative or an inhibitory mode of action. Here we address Bcl-2 proteins as major therapeutic targets for the treatment of atherosclerosis and underscore the need for the novel preventive and therapeutic interventions against atherosclerosis, which should be designed in the light of molecular mechanisms regulating apoptosis of vascular cells in atherosclerotic lesions

    Positive Regulation by GABABR1 Subunit of Leptin Expression through Gene Transactivation in Adipocytes

    Get PDF
    Background: The view that c-aminobutyric acid (GABA) plays a functional role in non-neuronal tissues, in addition to an inhibitory neurotransmitter role in the mammalian central nervous system, is prevailing, while little attention has been paid to GABAergic signaling machineries expressed by adipocytes to date. In this study, we attempted to demonstrate the possible functional expression of GABAergic signaling machineries by adipocytes. Methodology/Principal Findings: GABAB receptor 1 (GABABR1) subunit was constitutively expressed by mouse embryonic fibroblasts differentiated into adipocytes and adipocytic 3T3-L1 cells in culture, as well as mouse white adipose tissue, with no responsiveness to GABA BR ligands. However, no prominent expression was seen with mRNA for GABA BR2 subunit required for heteromeric orchestration of the functional GABABR by any adipocytic cells and tissues. Leptin mRNA expression was significantly and selectively decreased in adipose tissue and embryonic fibroblasts, along with drastically reduced plasma leptin levels, in GABA BR1-null mice than in wild-type mice. Knockdown by siRNA of GABA BR1 subunit led to significant decreases in leptin promoter activity and leptin mRNA levels in 3T3-L1 cells. Conclusions/Significance: Our results indicate that GABABR1 subunit is constitutively expressed by adipocytes to primarily regulate leptin expression at the transcriptional level through a mechanism not relevant to the function as a partner o

    A Potassium Metal-Organic Framework based on Perylene- 3,4,9,10-tetracarboxylate as Sensing Layer for Humidity Actuators

    Get PDF
    We have synthesized a novel three-dimensional metal-organic-framework (MOF) based on the perylene-3,4,9,10-tetracarboxylate linker and potassium as metallic centre. We report the formation of this K-based MOF using conventional routes with water as solvent. This material displays intense green photoluminescence at room temperature, and displays an aggregation dependent quenching. Correlation of the optical properties with the crystalline packing was confirmed by DFT calculations. We also demonstrate its potential to build humidity actuators with a reversible and reproducible response, with a change of 5 orders of magnitudes in its impedance at about 40% relative humidity (RH). This 3D-MOF is based on an interesting perylene derivative octadentate ligand, a moiety with interesting fluorescent properties and known component in organic semiconductors. To the best of our knowledge, this is the first time to build such a printed and flexible actuator towards humidity with a reversible response, enabling precise humidity threshold monitoring.This work was supported by the Junta de Andalucía (FQM-1484, and FQM-195). Red Guipuzcoana de Ciencia, Tecnología e Innovación (OF188/2017) and University of the Basque Country (GIU14/01, EHUA16/32). BB acknowledges funding by RyC-2012–10381 contract and computational resources provided by the RES and Alhambra supercomputing facilities. This work was also supported by the German Research Foundation (DFG) and the Technical University of Munich within the Open Access Publishing Funding Programme

    Technology Transfer in the Non-Traded Sector as a Means to Combat Global Warming

    Full text link
    The paper considers a situation where two countries - the North and the South - use a non-traded polluting input to produce the goods for final consumption. The North is more efficient in both, production and abatement processes. The study compares the effects of the transfer of abatement technology by the North to the South under autarky with the free trade situation, assuming that the North pre-commits to an international protocol to keep the global pollution under a fixed level. The conditions under which either full or partial technology is transferred in autarky are determined. It is shown that under free trade no such transfer is possible. With trade even though the North wants a complete transfer of technology, the South refuses it
    corecore