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Bow tie analysis

Esmaeil Zarei, Ali Azadeh, Nima Khakzad, Iraj Mohammadfam
Pipelines are one of the most popular and effective ways of transporting hazardous materials, especially natural gas. However, the rapid development of gas pipelines and stations in urban areas has introduced a serious threat to public safety and assets. Although different methods have been developed for risk analysis of gas transportation systems, a comprehensive methodology for risk analysis is still lacking, especially in natural gas stations. The present work is aimed at developing a dynamic and comprehensive quantitative risk analysis (DCQRA) approach for accident scenario and risk modeling of natural gas stations...
October 1, 2016: Journal of Hazardous Materials
Yong Hyun Kim, Hong Kwon, Jeongjun Kim, Kwang Yong Song
High-sensitivity distributed measurement of hydrostatic pressure is experimentally demonstrated by optical time-domain analysis of Brillouin dynamic grating (BDG) in polarization maintaining fibers (PMF's). The spectral shift of the BDG in four different types of PMF's are investigated under hydrostatic pressure variation from 14.5 psi (1 bar) to 884.7 psi (61 bar) with less than 2 m spatial resolution. The pressure sensitivity of BDG frequency is measured to be ‒1.69, + 0.65, + 0.78, and + 0.85 MHz/psi for a PM photonic crystal fiber (PM-PCF), two Bow-tie fibers, and a PANDA fiber, respectively, which is about 65 to 169 times larger than that of Brillouin frequency-based pressure sensing...
September 19, 2016: Optics Express
Fang Yan, Kaili Xu, Xiwen Yao, Yang Li
Biomass gasification technology has been rapidly developed recently. But fire and poisoning accidents caused by gas leakage restrict the development and promotion of biomass gasification. Therefore, probabilistic safety assessment (PSA) is necessary for biomass gasification system. Subsequently, Bayesian network-bow-tie (BN-bow-tie) analysis was proposed by mapping bow-tie analysis into Bayesian network (BN). Causes of gas leakage and the accidents triggered by gas leakage can be obtained by bow-tie analysis, and BN was used to confirm the critical nodes of accidents by introducing corresponding three importance measures...
2016: PloS One
Tomonobu Haba, Shuji Koyama, Yutaka Kinomura, Yoshihiro Ida, Masanao Kobayashi
The American Association of Physicists in Medicine (AAPM) task group 204 has recommended the use of size-dependent conversion factors to calculate size-specific dose estimate (SSDE) values from volume computed tomography dose index (CTDIvol) values. However, these conversion factors do not consider the effects of 320-detector-row volume computed tomography (CT) examinations or the new CT dosimetry metrics proposed by AAPM task group 111. This study aims to investigate the influence of these examinations and metrics on the conversion factors reported by AAPM task group 204, using Monte Carlo simulations...
September 2016: Australasian Physical & Engineering Sciences in Medicine
Ali Mirzajani, Sattar Aghataheri, Mohammad Ghoreishi, Ebrahim Jafarzadepour, Mohadese Mohammadinia
PURPOSE: This study reports the characteristics of corneal higher order aberrations (HOAs) in eyes with normal topographic pattern using the Pentacam scheimpflug system. METHODS: In this prospective, observational, comparative study, 165 eyes of 97 patients separated into five groups based on corneal topographic patterns were enrolled. All eyes received a comprehensive ophthalmologic examination including corneal tomographic analysis with the Pentacam system. Keratometry, corneal cylinder, and corneal aberrometric data were recorded and analyzed...
June 2016: Journal of Current Ophthalmology
Zhaleh Abdi, Hamid Ravaghi, Mohsen Abbasi, Bahram Delgoshaei, Somayeh Esfandiari
Purpose - The purpose of this paper is to apply Bow-tie methodology, a proactive risk assessment technique based on systemic approach, for prospective analysis of the risks threatening patient safety in intensive care unit (ICU). Design/methodology/approach - Bow-tie methodology was used to manage clinical risks threatening patient safety by a multidisciplinary team in the ICU. The Bow-tie analysis was conducted on incidents related to high-alert medications, ventilator associated pneumonia, catheter-related blood stream infection, urinary tract infection, and unwanted extubation...
May 9, 2016: International Journal of Health Care Quality Assurance
Assim Boukhayma, Antoine Dupret, Jean-Pierre Rostaing, Christian Enz
This paper presents the first low noise complementary metal oxide semiconductor (CMOS) deletedCMOS terahertz (THz) imager based on source modulation and in-pixel high-Q filtering. The 31 × 31 focal plane array has been fully integrated in a 0 . 13 μ m standard CMOS process. The sensitivity has been improved significantly by modulating the active THz source that lights the scene and performing on-chip high-Q filtering. Each pixel encompass a broadband bow tie antenna coupled to an N-type metal-oxide-semiconductor (NMOS) detector that shifts the THz radiation, a low noise adjustable gain amplifier and a high-Q filter centered at the modulation frequency...
2016: Sensors
Khalique Newaz, K Sriram, Debajyoti Bera
Prion diseases are transmissible neurodegenerative diseases that arise due to conformational change of normal, cellular prion protein (PrPC) to protease-resistant isofrom (rPrPSc). Deposition of misfolded PrpSc proteins leads to an alteration of many signaling pathways that includes immunological and apoptotic pathways. As a result, this culminates in the dysfunction and death of neuronal cells. Earlier works on transcriptomic studies have revealed some affected pathways, but it is not clear which is (are) the prime network pathway(s) that change during the disease progression and how these pathways are involved in crosstalks with each other from the time of incubation to clinical death...
2015: PloS One
Nima Abedpour, Markus Kollmann
BACKGROUND: A universal feature of metabolic networks is their hourglass or bow-tie structure on cellular level. This architecture reflects the conversion of multiple input nutrients into multiple biomass components via a small set of precursor metabolites. However, it is yet unclear to what extent this structural feature is the result of natural selection. RESULTS: We extend flux balance analysis to account for limited cellular resources. Using this model, optimal structure of metabolic networks can be calculated for different environmental conditions...
2015: BMC Systems Biology
Bruce R Whiting, Joshua D Evans, Andreea C Dohatcu, Jeffrey F Williamson, David G Politte
PURPOSE: Several areas of computed tomography (CT) research require knowledge about the intensity profile of the x-ray fan beam that is introduced by a bow tie filter. This information is considered proprietary by CT manufacturers, so noninvasive measurement methods are required. One method using real-time dosimeters has been proposed in the literature. A commercially available dosimeter was used to apply that method, and analysis techniques were developed to extract fan beam profiles from measurements...
October 2014: Medical Physics
Zhi Yuan, Nima Khakzad, Faisal Khan, Paul Amyotte
In this study, a methodology has been proposed for risk analysis of dust explosion scenarios based on Bayesian network. Our methodology also benefits from a bow-tie diagram to better represent the logical relationships existing among contributing factors and consequences of dust explosions. In this study, the risks of dust explosion scenarios are evaluated, taking into account common cause failures and dependencies among root events and possible consequences. Using a diagnostic analysis, dust particle properties, oxygen concentration, and safety training of staff are identified as the most critical root events leading to dust explosions...
February 2015: Risk Analysis: An Official Publication of the Society for Risk Analysis
D W Ding, Y R Ding, L N Li, Y J Cai, W B Xu
The purpose of this work was to study the giant strong component (GSC) of B. thuringiensis metabolic network by structural and functional analysis. Based on so-called "bow tie" structure, we extracted and studied GSC with its functional significance. Global structural properties such as degree distribution and average path length were computed and indicated that the GSC is also a small-world and scale-free network. Furthermore, the GSC was decomposed and functional significant for metabolism of these divisions were investigated by comparing to KEGG metabolic pathways...
April 2009: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
Monika C Kerckhoffs, Alexander F van der Sluijs, Jan M Binnekade, Dave A Dongelmans
OBJECTIVES: To improve patient safety, potential critical events should be analyzed for the existence of preventive barriers. The aim of this study was to prospectively identify existing and missing barriers using the Bow-Tie model. We expected that the analysis of these barriers would lead to feasible recommendations to improve safety in daily patient care. METHODS: Multidisciplinary teams of doctors and nurses on a 28 bed ICU conducted the study. The Bow-Tie analysis was performed on intrahospital transportation, unplanned extubation, and communication, which led to 9 critical events...
September 2013: Journal of Patient Safety
Shalini Singh, Areejit Samal, Varun Giri, Sandeep Krishna, Nandula Raghuram, Sanjay Jain
Unraveling the structure of complex biological networks and relating it to their functional role is an important task in systems biology. Here we attempt to characterize the functional organization of the large-scale metabolic networks of three microorganisms. We apply flux balance analysis to study the optimal growth states of these organisms in different environments. By investigating the differential usage of reactions across flux patterns for different environments, we observe a striking bimodal distribution in the activity of reactions...
May 2013: Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
L Romeo, D Coquillat, M Pea, D Ercolani, F Beltram, L Sorba, W Knap, A Tredicucci, M S Vitiello
The development of self-assembled nanostructure technologies has recently opened the way towards a wide class of semiconductor integrated devices, with progressively optimized performances and the potential for a widespread range of electronic and photonic applications. Here we report on the development of field effect transistors (FETs) based on semiconductor nanowires (NWs) as highly-sensitive room-temperature plasma-wave broadband terahertz (THz) detectors. The electromagnetic radiation at 0.3 THz is funneled onto a broadband bow-tie antenna, whose lobes are connected to the source and gate FET electrodes...
May 31, 2013: Nanotechnology
A C Pearson, S Jamieson, M R Linford, B M Lunt, R C Davis
We have fabricated nanoscale fuses from CVD graphene sheets with a 'bow tie' geometry for write-once-read-many data storage applications. The fuses are programmed using thermal oxidation driven by Joule heating. Fuses that were 250 nm wide with 2.5 μm between contact pads were programmed with average voltages and powers of 4.9 V and 2.1 mW, respectively. The required voltages and powers decrease with decreasing fuse sizes. Graphene shows extreme chemical and electronic stability; fuses require temperatures of about 400 °C for oxidation, indicating that they are excellent candidates for permanent data storage...
April 5, 2013: Nanotechnology
Koji Toriyama, Tomoyuki Inoue, Takashi Suzuki, Ritsuko Higashiura, Naoyuki Maeda, Yuichi Ohashi
PURPOSE: To report a case of spontaneous bleb formation in a presumed pellucid marginal corneal degeneration with acute hydrops. METHODS: A 51-year-old man reported sudden ocular pain with a lower conjunctival mass in his left eye. A clinical examination was performed to investigate this lesion. RESULTS: The intraocular pressure in the left eye was markedly lower compared with that in the opposite eye. Slit-lamp examination of the left eye showed a conjunctival mass inferior to the corneoscleral limbus adjacent to corneal epithelial and stromal edema without perforation...
June 2013: Cornea
Zhihai Wang, Takashi Nakajima, Shinpei Matsuda, Susumu Komiyama
Charge sensitive infrared photo transistors (CSIPs) made in GaAs/AlGaAs bilayer two-dimensional electron systems (2DESs) serve as sensitive photodetectors in the mid- and long-wavelength infrared regions. A new design of CSIP is proposed to expand the wavelength range to longer wavelengths (λ > 36 μm). Remarkably improved detector performance is demonstrated for λ ≈ 39 μm. In CSIPs electrons are photo-excited in a floating gate (FG) served by an isolated region of upper layer 2DESs. In the new design (i) a bow-tie antenna couples incident radiation to an FG far smaller in size (2-3 μm) than the wavelength and (ii) excited electrons 'laterally' escape from the FG via tunneling through a barrier formed by biased metal cross gates...
January 18, 2013: Nanotechnology
S-W Son, C Christensen, G Bizhani, D V Foster, P Grassberger, M Paczuski
For many real-world networks only a small "sampled" version of the original network may be investigated; those results are then used to draw conclusions about the actual system. Variants of breadth-first search (BFS) sampling, which are based on epidemic processes, are widely used. Although it is well established that BFS sampling fails, in most cases, to capture the IN component(s) of directed networks, a description of the effects of BFS sampling on other topological properties is all but absent from the literature...
October 2012: Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
M F Ciappina, Srdjan S Aćimović, T Shaaran, J Biegert, R Quidant, M Lewenstein
We study high-order harmonic generation (HHG) resulting from the illumination of plasmonic nanostructures with a short laser pulse of long wavelength. We demonstrate that both the confinement of the electron motion and the inhomogeneous character of the laser electric field play an important role in the HHG process and lead to a significant increase of the harmonic cutoff. In particular, in bow-tie nanostructures with small gaps, electron trajectories with large excursion amplitudes experience significant confinement and their contribution is essentially suppressed...
November 19, 2012: Optics Express
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