45,176 research outputs found
Settling of finite-size particles in isotropically forced, homogeneous turbulence: interface-resolved simulations
No full textWe have simulated the gravity-induced settling of finite-size particles in a turbulent background flow which is forced in a statistically-stationary fashion. The simulations are accurately resolving the solid-fluid interface with the aid of an immersed boundary technique [1]. The parameters of the simulation are (apart from background turbulence) identical to those of reference [2], where particle clustering was observed at a Galileo number of 178 and a solid volume fraction of 0.005. In the present case, it is found that a relative turbulence intensity of 0.24 leads to the disappearance of the clusters; as a consequence, the increase in average particle settling velocity found in [2] also vanishes. [1] M. Uhlmann. An immersed boundary method with direct forcing for the simulation of particulate flows. J. Comput. Phys., 209(2):448–476, 2005. [2] M. Uhlmann and T. Doychev. Sedimentation of a dilute suspension of rigid spheres at intermediate Galileo numbers: the effect of clustering upon the particle motion. J. Fluid Mech., 752:310–348, 2014
Mesophilic-hydrothermal-thermophilic (M-H-T) digestion of green corn straw
No full textMesophilic-hydrothermal (80-160 degrees C, 30 min)-thermophilic (M-H-T) digestion and control tests of mesophilic (M), thermophilic (T), hydrothermal-mesophilic (H-M), and mesophilic-thermophilic digestion (M-T) of green corn straw were conducted for a 20-day fermentation period. The results indicate that M-H-T is an efficient method to improve methane production. A maximum methane yield of 371.74 mL/g volatile solid was obtained by the M (3 days)-H (140 degrees C)-T (17 days) process, which was 20.44%, 16.55%, 31.44%, and 14.31% higher than the yields of the M, T, 140-M, and M-T processes. The enhanced methane production was attributed to (1) the improved hemicellulose degradation and lignin disorganization; (2) prevention of the degradation of soluble sugar, easily hydrolyzed hemicellulose and cellulose into furfural and methylfurfural; and (3) lack of formation of Maillard reaction products during initial hydrothermal treatment. (C) 2015 Elsevier Ltd. All rights reserved
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
The maternal immune system during pregnancy and its influence on fetal development
No full textThe maternal immune system plays a critical role in the establishment, maintenance, and completion of a healthy pregnancy. However, the specific mechanisms utilized to achieve these goals are not well understood. Various cells and molecules of the immune system are key players in the development and function of the placenta and the fetus. Effector cells of the immune system act to promote and yet limit placental development. The T helper 1 (Th1)/T helper 2 (Th2) immune shift during pregnancy is well established. A fine balance between proinflammatory and anti-inflammatory influences is required. We herein review the evidence regarding maternal tolerance of fetal tissues and the underlying cell-mediated immune and humoral (hormones and cytokines) mechanisms. We also note the many unanswered questions in our understanding of these mechanisms. In addition, we summarize the clinical manifestations of an altered maternal immune system during pregnancy related to susceptibility to common viral, bacterial, and parasitic infections, as well as to autoimmune diseases.Peer reviewe
Erosie door open taludbekledingen. Samenvattend verslag + Bijlage A t/m D
No full textOpen taludbekledingen die bestaan uit in verband geplaatste betonblokken met gaten, bieden de mogelijkheid vegetatie te doen groeien, waardoor mogelijk een milieuvriendelijke oever kan worden verkregen. In het pioniersstadium van de vegetatie is het evenwel ongewenst dat de gatvulling uitspoelt. Teneinde de relatie tussen waterbeweging en erosie van de gatvulling vast te stellen, is door de Dienst Weg- en Waterbouwkunde van Rijkswaterstaat per brief d.d. 16 maart 1987 (kenmerk WB 570), opdracht verleend aan het Waterloopkundig Laboratorium tot het uitvoeren van onderzoek naar de erosie door open taludbekledingen. Het doel van het onderzoek is het ontwikkelen van ontwerprichtlijnen voor taludbekledingen met gaten die groter zijn dan de zand- of filterkorrels eronder. Hiertoe dient de kritieke waterbeweging bij een oever- of dijkbekleding te worden vastgesteld, waarbij nog toelaatbare erosie is te verwachten. De toelaatbare erosie mag daarbij maximaal gelijk zijn aan de hoeveelheid sediment in de gaten. Filter- of basismateriaal gelegen onder de elementen mag dus niet uitspoelen. Bij oeverbekledingen waar vegetatie een rol moet gaan spelen, is de toelaatbare erosie kleiner, dat wil zeggen in de gaten dient sediment achter te blijven.Steenzettingen - TAW/EN
Probable disseminated Mycobacterium abscessus subspecies bolletii infection in a patient with idiopathic CD4+ T lymphocytopenia: a case report.
No full textINTRODUCTION: Rapidly growing mycobacteria are opportunistic pathogens in patients with underlying riskfactors. Mycobacterium abscessus subsp. bolletii is a newly recognized member of rapidlygrowing mycobacteria, isolated from respiratory tract and cutaneous infections.
CASE PRESENTATION: We describe a case of chronic disseminated infection caused by M. abscessus subsp. bolletiiin a 38-year-old Sri Lankan man with idiopathic CD4+ T lymphocytopenia. Idiopathic CD4+T lymphocytopenia is a rare cause of immunodysfunction that, similar to humanimmunodeficiency virus infection. M. abscessus subsp. bolletii infection was diagnosed byculture isolation from two sputum samples.
CONCLUSIONS: To the best of our knowledge this is the first report of M. abscessus subsp. bolletiidisseminated infection in a patient affected by idiopathic CD4+ T lymphocytopenia. Incontrast to previous reports, the isolate of M. abscessus subsp. bolletii presented intermediateresistance to clarithromycin and was susceptible to cefoxitin and imipenem
Model Based Building Chilled Water Loop Delta-T Fault Diagnosis
No full textImproving chilled water delta-T, which is the temperature difference of chilled water supply and return temperature, in campus buildings that are connected to a central distribution loop will not only improve the power consumption of the building through reduced tertiary (building) pumping power but the impact on the central distribution system and chiller efficiencies will be even greater. A degraded delta-T is almost inevitable and it can be expected to fall to about one-half to two-thirds of design at low loads (Taylor, 2002) due to various causes, such as air entering and leaving temperatures, chilled water supply temperature, type and effectiveness of flow control valves, tertiary connection configuration types and operation, coil cooling loads, air economizers, etc. However, in most variable-flow chilled water with 2-way control valve systems, the root cause of low delta-T is at coil side (Zhang, 2012), for example the geometric configuration of coil. This paper firstly discusses chilled water coil heat exchanger model results to help define methods for detecting opportunities for improved delta-T when analyzing campus building systems for performance optimization measures. Meanwhile, the author developed an effectiveness-NTU cooling coil models for a case study building containing chilled water coils with a range of design configurations to study cooling coil delta-T characteristics under various conditions in order to diagnose the low delta-T imposed on the chilled water distribution loop by the building's chilled water system under various loading conditions. The results show model-based building chilled water Loop delta-T fault diagnosis is an effective way to evaluate existing building chilled water loop delta-T performance and identify avoidable or resoluble causes for improving chilled water loop delta-T
High Speed Non-Contact Ultrasonic Guided Wave Inspections of Rails
No full textThis paper describes a new system for high-speed and non-contact rail defect detection being developed at the University of California at San Diego (UCSD). A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection has been tested at the UCSD Rail Defect Farm. This solution presents an improvement over the previously considered laser/air-coupled hybrid system because it replaces the costly and hard-to-maintain laser with a much cheaper, faster, and easier-to-maintain air-coupled transmitter. In addition to a real-time statistical analysis algorithm, the prototype uses a specialized filtering approach to mitigate the inherently poor signal-to-noise ratio of the air-coupled ultrasonic measurements in rail steel. The laboratory results indicate that the prototype is able to detect internal rail defects with a high reliability. Various aspects of the prototype have been designed with the aid of numerical analyses. In particular, simulations of ultrasonic guided wave propagation in rails have been performed using a Local Interaction Simulation Approach (LISA) algorithm. Many of the system operating parameters were selected based on Receiver Operating Characteristic (ROC) curves, which provide a quantitative manner to evaluate different detection performances based on the trade-off between detection rate and false positive rate. Extensions of the system capability are planned to add rail surface characterization to the internal rail defect detection to optimize rail grinding operations
C3H7NO2S effect on concrete steel-rebar corrosion in 0.5 M H2SO4 simulating industrial/microbial environment
No full textThis paper investigates C3H7NO2S (Cysteine) effect on the inhibition of reinforcing steel corrosion in concrete immersed in 0.5 M H2SO4, for simulating industrial/microbial environment. Different C3H7NO2S concentrations were admixed, in duplicates, in steel-reinforced concrete samples that were partially immersed in the acidic sulphate environment. Electrochemical monitoring techniques of open circuit potential, as per ASTM C876-91 R99, and corrosion rate, by linear polarization resistance, were then employed for studying anticorrosion effect in steel-reinforced concrete samples by the organic hydrocarbon admixture. Analyses of electrochemical test-data followed ASTM G16-95 R04 prescriptions including probability distribution modeling with significant testing by Kolmogorov-Smirnov and student's t-tests statistics. Results established that all datasets of corrosion potential distributed like the Normal, the Gumbel and the Weibull distributions but that only the Weibull model described all the corrosion rate datasets in the study, as per the Kolmogorov-Smirnov test-statistics. Results of the student's t-test showed that differences of corrosion test-data between duplicated samples with the same C3H7NO2S concentrations were not statistically significant. These results indicated that 0.06878 M C3H7NO2S exhibited optimal inhibition efficiency η = 90.52±1.29% on reinforcing steel corrosion in the concrete samples immersed in 0.5 M H2SO4, simulating industrial/microbial service-environment
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
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