Hydrodynamic instabilities in gaseous detonations: comparison of Euler, Navier–Stokes, and large-eddy simulation

A large-eddy simulation is conducted to investigate the transient structure of an unstable detonation wave in two dimensions and the evolution of intrinsic hydrodynamic instabilities. The dependency of the detonation structure on the grid resolution is investigated, and the structures obtained by large-eddy simulation are compared with the predictions from solving the Euler and Navier–Stokes equations directly. The results indicate that to predict irregular detonation structures in agreement with experimental observations the vorticity generation and dissipation in small scale structures should be taken into account. Thus, large-eddy simulation with high grid resolution is required. In a low grid resolution scenario, in which numerical diffusion dominates, the structures obtained by solving the Euler or Navier–Stokes equations and large-eddy simulation are qualitatively similar. When high grid resolution is employed, the detonation structures obtained by solving the Euler or Navier–Stokes equations directly are roughly similar yet equally in disagreement with the experimental results. For high grid resolution, only the large-eddy simulation predicts detonation substructures correctly, a fact that is attributed to the increased dissipation provided by the subgrid scale model. Specific to the investigated configuration, major differences are observed in the occurrence of unreacted gas pockets in the high-resolution Euler and Navier–Stokes computations, which appear to be fully combusted when large-eddy simulation is employed

A Case Report of Tuberculosis with Extrapulmonary Manifestations

BACKGROUND AND OBJECTIVE: Mycobacterium tuberculosis affects millions of people in the world and Iran is one of the endemic areas. This disease has a wide range of manifestations, which is pulmonary in 80 – 85% of cases and extrapulmonary in 15 – 20% of cases. The most notable extrapulmonary infection sites are lymph nodes, pleura, genitourinary system and digestive system. Considering the prevalence of tuberculosis in Iran, familiarity with the uncommon manifestations of this infection seems to be essential for timely diagnosis and treatment. Therefore, a rare extrapulmonary manifestation of tuberculosis is reported here. CASE REPORT: The patient was a 64 – year – old woman who was hospitalized due to fever, icterus, decreased consciousness and progressive asymmetrical weakness of the limbs. Symptoms of focal neurologic deficits and heart murmurs were found in examinations. During the tests, including brain and spinal imaging, cerebrospinal fluid analysis, computed tomography of the abdomen and pelvis, and echocardiography, extrapulmonary tuberculosis (cerebral abscess, spondylitis, liver and spleen abscess, psoas muscle abscess, and possible endocarditis) was confirmed. Four-drug regimen including isoniazid, rifampin, ethambutol, and pyrazinamide with vitamin B6 was started for two months, and two-drug regimen continued for 10 months. At the end of the course of treatment, the patient was able to walk with the cane in good general condition. CONCLUSION: Considering the reported case, paying attention to some of the more uncommon manifestations of the disease can prevent mortality and disability

Long-Term Changes of Source Apportioned Particle Number Concentrations in a metropolitan Area of the Northeastern United States

The northeastern United States has experienced significant emissions reductions in the last two decades leading to a decrease in PM2.5, major gaseous pollutants (SO2, CO, NOx) and ultrafine particles (UFPs) concentrations. Emissions controls were implemented for coal-fired power plants, and new heavy-duty diesel trucks were equipped with particle traps and NOx control systems, and ultralow sulfur content is mandatory for both road and non-road diesel as well as residual oil for space heating. At the same time, economic changes also influenced the trends in air pollutants. Investigating the influence of these changes on ultrafine particle sources is fundamental to determine the success of the mitigation strategies and to plan future actions. Particle size distributions have been measured in Rochester, NY since January 2002. The particle sources were investigated with positive matrix factorization (PMF) of the size distributions (11–470 nm) and measured criteria pollutants during five periods (2002–2003, 2004–2007, 2008–2010, 2011–2013, and 2014–2016) and three seasons (winter, summer, and transition). Monthly, weekly, and hourly source contributions patterns were evaluated

Loss of vision after transurethral resection of prostate: A case report

The overall complication rate of Transurethral resection of prostate (TURP) is about 11.1. Amongst all complications, ocular complications are one of the rarest. In this paper, we present a case of vision loss due to paradoxical embolism as a rare complication following TURP. Ocular complications are very rare in urological surgeries but can happen due to paradoxical embolism following patent foramen ovale. Therefore, we recommend the early diagnosis and treatment of PFO prior to this type of surgery. © 202

Evolution of Surface Acoustic Waves in an Optical Microfiber

This paper reports stimulated Brillouin scattering characterization in a tapered optical fiber using full-vectorial finite element-based numerical methods. Numerical simulations of both optical and acoustic waves’ propagation through a tapered microfiber have been carried out. Acoustic modes over a range of wavenumber for different fiber core radii are obtained and nature of their both dominant and non-dominant displacement vector profiles are studied and discussed. Acoustic mode profiles show confinement of the acoustic wave predominantly at the core cladding interface. In addition, the acoustooptical overlap factors at different fiber radii are also presented

Conscious sedation and analgesia in colonoscopy: Ketamine/propofol combination has superior patient satisfaction versus fentanyl/propofol

Background: Colonoscopy is performed without preparing sedation in many countries. However, according to the current literature patients are more satisfied when appropriate sedation is prepared for them. Objectives: We hypothesize that propofol-ketamine may prepare more patient satisfaction compared to propofol-fentanyl combination. Patients and Methods: Sixty adult patients older than 18 with ASA physical status of I, II or III were enrolled in the present study after providing the informed consent. They were prospectively randomized into two equal groups: 1- Group PF: was scheduled to receive IV bolus dose of fentanyl 1μg/kg and propofol 0.5mg/kg. 2- Group PK: was scheduled to receive IV bolus dose of ketamine 0.5mg/kg and propofol 0.5mg/kg. As a primary goal, patient's satisfaction was assessed by the use a Likert five-item scoring system in the recovery. Comparisons of hemodynamic parameters (mean heart rate, mean systolic blood pressure, mean diastolic blood pressure), mean Spo2 values during the procedure and side effects such as nausea, vomiting, and psychological reactions during the recovery period were our secondary goals. Level of sedation during the colonoscopy was assessed with the Observer's Assessment of Alertness/Sedation score (OAA/S). Results: Mean satisfaction scores in the group PK were significantly higher than the group PF (P = 0.005) while the level of sedation during the procedure was similar (P = 0.17). Hemodynamic parameters and SpO2 values were not significantly different (P > 0.05). Incidence of nausea and vomiting was the same in both groups. Conclusions: IV bolus injection of propofol-ketamine can lead to more patients' satisfaction than the other protocols during colonoscopy. © 2013 Iranian Society of Regional Anesthesia and Pain Medicine

Cosmology of a Scalar Field Coupled to Matter and an Isotropy-Violating Maxwell Field

Motivated by the couplings of the dilaton in four-dimensional effective actions, we investigate the cosmological consequences of a scalar field coupled both to matter and a Maxwell-type vector field. The vector field has a background isotropy-violating component. New anisotropic scaling solutions which can be responsible for the matter and dark energy dominated epochs are identified and explored. For a large parameter region the universe expands almost isotropically. Using that the CMB quadrupole is extremely sensitive to shear, we constrain the ratio of the matter coupling to the vector coupling to be less than 10^(-5). Moreover, we identify a large parameter region, corresponding to a strong vector coupling regime, yielding exciting and viable cosmologies close to the LCDM limit.Comment: Refs. added, some clarifications. Published in JHEP10(2012)06