1,345 research outputs found

    Design of the Target Dump Injection Segmented (TDIS) in the framework of the High Luminosity Large Hadron Collider (HL-LHC) project

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    The High Luminosity Large Hadron Collider (HL-LHC) Project at CERN calls for increasing beam brightness and intensity. In this scenario, most equipment has to be redesigned and rebuilt. In particular, beam intercepting devices (such as dumps, collimators, absorbers and scrapers) have to withstand impact or scraping of the new intense HL-LHC beams without failure. Furthermore, minimizing the electromagnetic beam-device interactions is also a key design driver since they can lead to beam instabilities and excessive thermo-mechanical loading of devices. In this context, the present study assesses the conceptual design quality of the new LHC injection protection absorber, the Target Dump Injection Segmented (TDIS), from an electromagnetic and thermo-mechanical perspective. This contribution analyzes the thermo-mechanical response of the device considering two cases: an accidental beam impact scenario and another accidental scenario with complete failure of the RFcontacts. In addition, this paper presents the preliminary results from the simulation of the energy deposited by the two counter-rotating beams circulating in the device

    Evaluating The Use of Fairmount Dam Fish Passage Facility By Anadromous Fishes In The Schuylkill River, Philadelphia, Pennsylvania

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    The Schuylkill River in Southeaster Pennsylvania once supported massive spring runs of anadromous fishes until the construction of dams in the early 1800\u27s. American shad (Alosa sapidissima), striped bass (Morone saxatilis), and river herring (alewife Alosa pseudoharengus and blueback herring A. aestivalis) ascended the Schuylkill River as far upstream as Pottsville (160 rkm), but have not done so since 1820, when Fairmount Dam (13.6 rkm) was built. The dam served as a physical barrier to migratory fishes, completely blocking upstream movement and access to critical spawning grounds. In 1979, a vertical slot fish passage facility was constructed on the west side of Fairmount Dam, however, very few anadromous species were utilizing the passage and the fishway was abandoned in 1984. No fish counts were conducted from 1984 to 2004, until Philadelphia Water Department biologists took responsibility for maintenance and operation of the fishway and developed a digital video monitoring system to record fish passage. An underwater viewing room and window allows direct observation of fishes swimming through the fishway and is a primary means for evaluating fish passage. In 2004, there were 6,438 fish of 23 species that ascended Fairmount fishway, including 91 American shad, 161 striped bass, and 2 river herring. A total of 8,017 fishes representing 25 species were counted passing through the fishway in 2005, including 41 American shad, 127 striped bass, and 5 river herring. In 2006, a total of 16,850 fishes representing 26 species were counted passing through the fishway including 345 American shad, 9 hickory shad, 61 striped bass, and 7 river herring, marking an astonishing 279% increase in American shad passage from 2004 to 2006. The interannual trend in relative abundance of American Shad below Fairmount Dam increased, as did overall shad passage trends in the fishway. Continued monitoring of fish passage will be a critical component in assessing anadromous fish restoration efforts on the Schuylkill River

    LSD1: more than demethylation of histone lysine residues

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    Lysine-specific histone demethylase 1 (LSD1) represents the first example of an identified nuclear protein with histone demethylase activity. In particular, it plays a special role in the epigenetic regulation of gene expression, as it removes methyl groups from mono- and dimethylated lysine 4 and/or lysine 9 on histone H3 (H3K4me1/2 and H3K9me1/2), behaving as a repressor or activator of gene expression, respectively. Moreover, it has been recently found to demethylate monomethylated and dimethylated lysine 20 in histone H4 and to contribute to the balance of several other methylated lysine residues in histone H3 (i.e., H3K27, H3K36, and H3K79). Furthermore, in recent years, a plethora of nonhistone proteins have been detected as targets of LSD1 activity, suggesting that this demethylase is a fundamental player in the regulation of multiple pathways triggered in several cellular processes, including cancer progression. In this review, we analyze the molecular mechanism by which LSD1 displays its dual effect on gene expression (related to the specific lysine target), placing final emphasis on the use of pharmacological inhibitors of its activity in future clinical studies to fight cancer

    Risk Analysis of Organic Cropping Systems in Minnesota

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    When all strategies received conventional market prices, 4-year cropping sequences had greater net returns than 2-year sequences, and the organic input, 4-year strategy had the highest net return. Adding 50% of the estimated organic premium, the 4-year, organic strategy dominated all low- and high-purchased input strategies.Crop Production/Industries, Risk and Uncertainty,

    Intruding implements: a pictorial review of retained surgical foreign objects in neuroradiology

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    Intra-cranial and spinal foreign body reactions represent potential complications of medical procedures. Their diagnosis may be challenging as they frequently show an insidious clinical presentation and can mimic other life-threatening conditions. Their pathophysiological mechanism is represented by a local inflammatory response due to retained or migrated surgical elements. Cranial interventions may be responsible for the presence of retained foreign objects represented by surgical materials (such as sponges, bone wax, and Teflon). Spinal diagnostic and therapeutic procedures, including myelography, chordotomy, vertebroplasty, and device implantation, are another potential source of foreign bodies. These reactions can also follow material migration or embolization, for example in the case of Lipiodol, Teflon, and cement vertebroplasty. Imaging exams, especially CT and MRI, have a central role in the differential diagnosis of these conditions together with patient history. Neuroradiological findings are dependent on the type of material that has been left in or migrated from the surgical area. Knowledge of these entities is relevant for clinical practice as the correct identification of foreign bodies and related inflammatory reactions, material embolisms, or migrations can be difficult. This pictorial review reports neuroradiological semeiotics and differential diagnosis of foreign body-related imaging abnormalities in the brain and spine

    Modelling of the carburizing and nitriding processes

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    The thermo-chemical diffusion process of carburizing and nitriding was modeled in the present study. The analyses led to the prediction of surface hardened layers dimensions and hardness in commercial steels. A diffusion model based on Fick’s laws was applied to such steels in order to describe the growth kinetics of layers, then the analytical model was employed to perform finite element calculations. In such a way it was possible to calculate the carbon and nitrogen concentration in the cross sections of cylindrical samples and the consequent hardness profiles coupled with those of the residual stresses. The results from analytical model and FE calculations were compared with experimental data

    Lesions associated with mineral deposition in the lymph nodes and lungs of cattle: a case-control study of environmental health hazard.

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    This report focuses on the state of health of the cattle raised in the district of Taranto - city of Italy rated as environmentally at risk. Representative samples of lungs, bronchial and mediastinal lymph nodes of cattle from district of Taranto's slaughterhouses were collected. After a macroscopic examination, samples with marked lesions were processed for light microscopy. Samples were also observed with polarized light microscopy, scanning electron microscopy and with microanalysis. The macroscopic examination revealed that 60 out of 183 samples showed marked lesions. Lung alterations were characterized by thickening of the alveolar septa and by the latter's modifying action on the alveolar spaces, foci of fibrosis and bronchopulmonary inflammation. For 51 out of the 60 samples observed, the histological examination confirmed the presence of pneumoconiosis and lymph nodal anthracosis. Energy-dispersive X-ray microanalysis of lung samples identified a wide range of elements including silicon, aluminium, titanium, iron, carbon and small amount of the other metals. In the lymph-nodes the same kind of metals with a different levels of distribution was observed. Our survey on cattle farmed in areas at high risk of pollution may be helpful to the estimation of the exposure risk for man to environmental contaminants and to the evaluation of the occurrence of the pathological manifestations as well

    Impedance measurements and simulations on the TCT and TDI LHC collimators

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    The LHC collimation system is a critical element for the safe operation of the LHC machine and it is subject to continuous performance monitoring, hardware upgrade and optimization. In this work we will address the impact on impedance of the upgrades performed on the injection protection target dump (TDI), where the absorber material has been changed to mitigate the device heating observed in machine operation, and on selected secondary (TCS) and tertiary (TCT) collimators, where beam position monitors (BPM) have been embedded for faster jaw alignment. Con- cerning the TDI, we will present the RF measurements per- formed before and after the upgrade, comparing the result to heating and tune shift beam measurements. For the TCTs, we will study how the higher order modes (HOM) intro- duced by the BPM addition have been cured by means of ferrite placement in the device. The impedance mitigation campaign has been supported by RF measurements whose results are in good agreement with GdfidL and CST simula- tions. The presence of undamped low frequency modes is proved not to be detrimental to the safe LHC operation

    Efficiency, products and mechanisms of ethyl acetate oxidative degradation in air non-thermal plasma

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    Ethyl acetate (EA) is a popular solvent and diluent in many products and one of the most ubiquitous organic pollutants of indoor air. Although EA's ascertained toxicity is classified as low, exposure to its vapors at concentrations 400 ppm causes serious problems in humans. EA is thus a frequent target in testing novel technologies for air purification. We report here an investigation of EA oxidative degradation in air at room temperature and atmospheric pressure induced by corona discharges. Three corona regimes, dc-, dc+ and pulsed +, were tested in the same reactor under various experimental conditions with regard to EA initial concentration (C 0) and the presence of humidity in the system. The EA degradation process was monitored by gas chromatography (GC)-flame ionization detection, GC-mass spectrometry and Fourier transform infrared spectroscopy analysis of the treated gas. These analyses yielded the concentration of residual EA (C) and those of its major products of oxidation (CO2, CO) and revealed a few organic reaction intermediates formed along the oxidation chain. The process energy efficiency was determined as energy constant, k E (kJ-1 l) and as energy yield, EY (g kW-1 h-1). The efficiency depends on the type of corona (pulsed + >dc- >dc+), on the presence of humidity in the air (improvement in the case of dc-, little or no effect for dc+) and on C 0 (k E increases linearly with 1/C 0). CO2 and CO were the major carbon containing products, confirming the strong oxidizing power of air non-thermal plasma. Acetic acid and acetaldehyde were detected in very small amounts as reaction intermediates. The experimental results obtained in this work support the conclusion that different reactive species are involved in the initial step of EA oxidation in the case of dc- and dc+ corona air non-thermal plasma
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