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stokes flow before plane boundary with mixed stick-slip boundary conditions

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Applied Mathematics and Mechanics(English Edition) 2011年第6期32卷 795-804页

作者： N.AKHTAR G.A.H.CHOWDHURY s.K.sEN Department of Mathematics Shahjalal University of Science and Technology Research Centre for Mathematical and Physical sciences University of Chittagong

A general theorem for the stokes flow over a plane boundary with mixed stick-slip boundary conditions is established. This is done by using a representation for the velocity and pressure fields in the three-dimensional stokes flow in terms of a biharmonic function and a harmonic function. The earlier theorem for the stokes flow due to fundamental singularities before a no-slip plane boundary is shown to be a special case of the present theorem. Furthermore, in terms of the stokes stream function, a corollary of the theorem is also derived, providing a solution to the problem of the axisymmetric stokes flow along a rigid plane with stick-slip boundary conditions. The formulae for the drag and torque exerted by the fluid on the boundary are established. An illustrative example is given.

关键词： stokes flow stokes stream function stick-slip boundary conditions,harmonic function biharmonic function

A Combined Probabilistic and Optimization Approach for Improved Chemical Mixing systems Design

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Engineering（科研） 2011年第6期3卷 643-652页

作者： Matthew j. Opgenorth William E. McDermott Peter Laz Corinne s. Lengsfeld University of Denver Department of Mechanical and Materials Engineering 2390 S. York St. Suite 200 Denver CO

A design analysis of a mixing nozzle was performed using a combination of probabilistic and optimization techniques. A novel approach was utilized where probabilistic analysis was used to reduce the number of geometric constraints based on sensitivity factors. An optimization algorithm used only the most significant parameters to maximize mixing. A second probabilistic analysis was performed after optimization was com-plete in order to quantitatively predict the effects of manufacturing tolerances on mixing performance. This process for automated design is attractive over full parameter optimization techniques due to the computa-tional efficiency resulting from an intelligent reduction in evaluated variables.

关键词： Probabilistic Design Optimization Design Tolerance Design Computer-Aided Design

Invading from the garden？ A comparison of leaf herbivory for exotic and native plants in natural and ornamental settings

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Insect science 2012年第6期19卷 677-682页

作者： stephen F. Matter jessica R.Brzyski Christopher j. Harrison sara Hyams Clement Loo jessica Loomis Hannah R. Lubbers leeann seastrum Trevor I. stamper Adam M. stein Richard stokes Brandy s. Wilkerson Department of Biological sciences University of Cincinnati Cincinnati USA

The enemies release hypothesis proposes that exotic species can become in- vasive by escaping from predators and parasites in their novel environment. Agrawal et al. （Enemy release？ An experiment with congeneric plant pairs and diverse above- and below-ground enemies. Ecology, 86, 2979-2989） proposed that areas or times in which damage to introduced species is low provide opportunities for the invasion of native habitat. We tested whether ornamental settings may provide areas with low levels of herbivory for trees and shrubs, potentially facilitating invasion success. First, we compared levels of leaf herbivory among native and exotic species in ornamental and natural settings in Cincinnati, Ohio, United states. In the second study, we compared levels of herbivory for invasive and noninvasive exotic species between natural and ornamental settings. We found lower levels of leaf damage for exotic species than for native species; however, we found no differences in the amount of leaf damage suffered in ornamental or natural settings. Our results do not provide any evidence that ornamental settings afford additional release from herbivory for exotic plant species.

关键词： enemies release hypothesis forest herbivory host plant suburban urban

New Optimization Method, the Algorithms of Changes, for Heat Exchanger Design

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Chinese journal of Mechanical Engineering 2012年第1期25卷 55-62页

作者： TAM Houkuan TAM Lapmou TAM sikchung CHIO Chouhei GHAjAR Afshin j Department of Electromechanical Engineering Faculty of Science and TechnologyUniversity of Macao Department of Mathematics Faculty of Science and TechnologyUniversity of Macao school of Mechanical and Aerospace Engineering Oklahoma State University

Heat exchangers are widely used in the process engineering such as the chemical industries, the petroleum industries, and the HVAC applications etc. An optimally designed heat exchanger cannot only help the optimization of the equipment size but also the reduction of the power consumption. In this paper, a new optimization approach called algorithms of changes (AOC) is proposed for design and optimization of the shell-tube heat exchanger. This new optimization technique is developed based on the concept of the book of changes (I Ching) which is one of the oldest Chinese classic texts. In AOC, the hexagram operations in I Ching are generalized to binary string case and an iterative process, which imitates the I Ching inference, is defined. Before applying the AOC to the heat exchanger design problem, the new optimization method is examined by the benchmark optimization problems such as the global optimization test functions and the travelling salesman problem (TsP). Based on the TsP results, the AOC is shown to be superior to the genetic algorithms (GA). The AOC is then used in the optimal design of heat exchanger. The shell inside diameter, tube outside diameter, and baffles spacing are treated as the design (or optimized) variables. The cost of the heat exchanger is arranged as the objective function. For the heat exchanger design problem, the results show that the AOC is comparable to the GA method. Both methods can find the optimal solution in a short period of time.

关键词： optimization genetic algorithms (GA) travelling salesman problem (TsP) heat exchanger design algorithms of changes (AOC)

Peak-to-average power ratio reduction using selective mapping with unequal power distribution

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journal of Central south University 2012年第7期19卷 1902-1908页

作者： E.s.Hassan XU Zhu s.E.E1-Khamy M.I.Dessouky s.A.EI-Dolill F.E.Abd EI-samie Department of Electronics and Electrical Communications Faculty of Electronic EngineeringMenoufia UniversityMenouf 32952Egypt Department of Electrical Engineering and Electronics The University of LiverpoolLiverpool L693G JUK Department of Electrical Engineering Faculty of EngineeringAlexandria UniversityAlexandria 21544Egypt

A new approach for peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems was *** approach is based on assigning powers to the different subcarriers of OFDM using an unequal power distribution *** addition,a reduced complexity selective mapping (RC-sLM) scheme was *** proposed scheme is based on partitioning the frequency domain symbol sequence into several sub-blocks,and then each sub-block is multiplied by different phase sequences whose length is shorter than that used in the conventional sLM ***,a kind of low complexity conversions is used to replace the IFFT *** performance of the proposed RC-sLM scheme along with the new approach was studied with computer *** obtained results show that the proposed RC-sLM scheme is able to achieve the lowest computational complexity when compared with other low complexity schemes proposed in the literature while at the same time improves the PAPR reduction performance by about 0.3 dB.

关键词： orthogonal frequency division multiplexing (OFDM) peak-to-average power ratio (PAPR) computational complexity selective mapping scheme

Identification and Antimicrobial susceptibility of <i>Yersinia enterocolitica</i>Found in Chitterlings, Raw Milk and swine Fecal samples

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Advances in Microbiology 2018年第10期8卷 804-820页

作者： F. N. Drake s. Davis j. Khatiwada L. Williams North Carolina A & T state University North Carolina Research Campus Kannapolis NC USA

Foodborne illness is an escalating concern upon public health. The prevalence of Yersinia enterocolitica was assessed in chitterlings, raw milk and swine fecal from North Carolina. Uncleaned thirty chitterling samples procured from a local grocery store, forty-five swine fecal samples, and forty unpasteurized cow milk samples supplied by the University farm were evaluated for the presence of Y. enterocolitica. Isolates identified as presumptive positive were characterized as colonies with a pink or deep-red center on MacConkey and CIN agar, and verified further through polymerase chain reaction (PCR) for the presence of 16s rRNA gene for the Yersinia genera. Results showed that 4.4% swine fecal samples, 7.5% milk samples and 11.3% chitterling samples were presumptive positive for Y. enterocolitica by the direct plating method on selective agars. Of the thirty-chitterling samples examined by PCR for the 16s rRNA gene, 26% samples contained the identification gene for the bacteria of interest. After conducting virulence tests, the fecal samples were revealed as non-pathogenic. Only one of the milk samples were considered pathogenic and consisted of the following virulent genes: Yersinia heat-stable toxin (yst), invasion (inv), attachment invasion locus (ail), virulence regulon transcriptional activator (virF), Yersinia adehesin A (yadA), and the O:3 antigen gene (rfbC). seven out of the eight (87.5%) chitterling samples were shown to be pathogenic. Disc diffusion was conducted to determine the antimicrobial susceptibility of the isolates. Over half (55.5%) of the antimicrobial agents were found effective, with isolates being completely susceptible to ciprofloxacin, kanamycin, trimethoprim, cefotaxime, and gentamycin. Ampicillin was determined to be least effective, where 84.6% of the samples presented resistance to the drug. Random amplified polymorphic DNA (RAPD) analysis and ERIC-PCR techniques were used to evaluate genetic similarity among the Yersinia isolates. Th

关键词： Yersinia enterocolitica Polymerase Chain Reaction Antimicrobial

The predictive value of childhood blood pressure values for adult elevated blood pressure

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Open journal of Pediatrics 2013年第2期3卷 116-126页

作者： Robert j. Carrico shumei s. sun Adam P. sima Bernard Rosner Department of Medicine Harvard Medical School Boston USA school of Medicine Virginia Commonwealth University Richmond USA

Because of the paucity of serial blood pressure data on the same individuals, little is known about the accuracy of elevated blood pressure (BP) in childhood for predicting hypertension (HBP) later in life. The availability of long-term serial BP data from the Fels Longitudinal study (FLs) presents the opportunity to link HBP in adulthood directly to BP measured decades earlier in the same individuals as children. We analyzed serial data from 965 men and 1114 women in the FLs. We used an autoregressive-moving average (1, 1) [ARMA (1, 1)] longitudinal model to predict adult HBP from childhood values. For 15-year-old boys with sBP 15 mmHg and 30 mmHg above the average sBP of 90 mmHg, the probabilities of having HBP at age 35 are 0.18 and 0.33, respectively. The corresponding probabilities for 15-year-old girls are only 0.04 and 0.08. This striking sex difference in risk of HBP at age 35 between 15-year-old boys and girls indicates that the risk of developing HBP in women is low regardless of their childhood blood pressure at any age from 2 to 17 years. Men are about 4.25 times more likely to have HBP at age 35 than women over a range of sBP of 90 - 140 mmHg at age 15. The ARMA (1, 1) model allows the identification of boys at risk for HBP as adult men.

关键词： Blood Pressure Body Mass Index systolic Blood Pressure Diastolic Blood Pressure Adult Children

Initial evaluations of a Gulf of Mexico/Caribbean ocean forecast system in the context of the Deepwater Horizon disaster

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Frontiers of Earth science 2015年第4期9卷 605-636页

作者： Edward D. ZARON Patrick j. FITZPATRICK scott L. CROss john M. HARDING Frank L. BUB jerry D. WIGGERT Dong s. KO Yee LAU Katharine WOODARD Christopher N. K. MOOERs Department of Civil and Environmental Engineering Portland State University Portland OR 97207 USA Geosystems Research Institute Mississippi State University MSU Science & Technology Center Stennis Space Center MS 39529 USA NOAA National Coastal Data Development Center Stennis Space Center MS 29412 USA Northern Gulf Institute Mississippi State University MSU Science & Technology Center Stennis Space Center MS 39529 USA unaffiliated retired from the Naval Oceanographic Office Stennis Space Center MS 39522 USA Department of Marine science University of Southern Mississippi Stennis Space Center MS 39529 USA Oceanography Division Naval Research Laboratory Stennis Space Center MS 39529 USA

In response to the Deepwater Horizon （DwH） oil spill event in 2010, the Naval Oceanographic Office deployed a nowcast-forecast system covering the Gulf of Mexico and adjacent Caribbean sea that was designated Americas seas, or AMsEAs, which is documented in this manuscript. The DwH disaster provided a challenge to the application of available ocean-forecast capabilities, and also generated a historically large observational dataset. AMsEAs was evaluated by four complementary efforts, each with somewhat different aims and approaches： a university research consortium within an Integrated Ocean Observing system （IOOs） testbed; a petroleum industry consortium, the Gulf of Mexico 3-D Operational Ocean Forecast system Pilot Prediction Project （GOMEX-PPP）; a British Petroleum （BP） funded project at the Northern Gulf Institute in response to the oil spill; and the Navy itself. Validation metrics are presented in these different projects for water temperature and salinity profiles, sea surface wind, sea surface temperature, sea surface height, and volume transport, for different forecast time scales. The validation found certain geographic and time biases/errors, and small but systematic improvements relative to earlier regional and global modeling efforts. On the basis of these positive AMsEAs validation studies, an oil spill transport simulation was conducted using archived AMsEAs nowcasts to examine transport into the estuaries east of the Mississippi River. This effort captured the influences of Hurricane Alex and a non-tropical cyclone off the Louisiana coast, both of which pushed oil into the western Mississippi sound, illustrating the importance of the atmospheric influence on oil spills such as DwH.

关键词： Gulf of Mexico Deepwater Horizon ocean forecasting skill assessment

Concurrent multi-peak Bragg coherent x-ray diffraction imaging of 3D nanocrystal lattice displacement via global optimization

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npj Computational Materials 2023年第1期9卷 1579-1590页

作者： siddharth Maddali Travis D.Frazer Nazar Delegan Katherine j.Harmon sean E.sullivan Marc Allain Wonsuk Cha Alan Dibos Ishwor Poudyal saugat Kandel Youssef s.G.Nashed F.joseph Heremans Hoydoo You Yue Cao stephan O.Hruszkewycz Materials science Division Argonne National LaboratoryLemontIL 60439USA Center for Molecular Engineering Argonne National LaboratoryLemontIL 60439USA Aix-Marseille Univ CNRSCentrale MarseilleInstitut FresnelMarseilleFrance X-ray science Division Argonne National LaboratoryLemontIL 60439USA Center for Nanoscale Materials Argonne National LaboratoryLemontIL 60439USA Mathematics&Computer science Division Argonne National LaboratoryLemontIL 60439USA Pritzker school of Molecular Engineering University of Chicago5640 South Ellis AvenueChicagoIL 60637USA sLAC National Accelerator Laboratory Menlo ParkCAUSA

In this paper we demonstrated a method to reconstruct vector-valued lattice distortion fields within nanoscale crystals by optimization of a forward model of multi-reflection Bragg coherent diffraction imaging(MR-BCDI)*** method flexibly accounts for geometric factors that arise when making BCDI measurements,is amenable to efficient inversion with modern optimization toolkits,and allows for globally constraining a single image reconstruction to multiple Bragg peak *** is enabled by a forward model that emulates the multiple Bragg peaks of a MR-BCDI experiment from a single estimate of the 3D crystal *** present this forward model,we implement it within the stochastic gradient descent optimization framework,and we demonstrate it with simulated and experimental data of nanocrystals with inhomogeneous internal lattice *** find that utilizing a global optimization approach to MR-BCDI affords a reliable path to convergence of data which is otherwise challenging to reconstruct.

关键词： optimization coherent lattice