bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Approach for Lattice Boltzmann Modeling of Energy Transport
Authors: Wang Dadong , Ma Yanbao
Published: October 2013

It is well known that Fourier law breaks down for the prediction of heat conduction in nano-scale, where the length scale is comparable to the mean free path of energy carriers. Over the past decade, Boltzmann transport equation (BTE) has been used to predict thermal transport in dielectrics and semiconductors at micro-scale and nano-scale. In this work, a new modified gray model is obtained from BTE. The implicit lattice Boltzmann method (LBM) is developed to simulate the thermal transport process. Based on the new model, we can derive Guyer-Krumhansl equation. Transient heat conduction through a thin nano-film and hotspot self-heating in sub-micron transistors are examined. The numerical results are compared with those provided by Fourier, Cattaneo, and Guyer-Krumhansl equation.
Mode-Wise Phonon Properties of Bismuth Telluride
Authors: Wang Yaguo , Xu Xianfan
Published: October 2013

Thermal transport properties and thermal transport control are important for many materials, for example, low thermal conductivity is desirable for thermoelectric materials. Knowledge of mode-wise phonon properties is crucial to identify dominant phonon modes for thermal transport and design effective phonon barriers for thermal transport control. In this paper, we adopt the normal mode analysis to investigate spectral phonon properties, and to calculate phonon dispersion relations and phonon relaxation times in bismuth telluride. Our results agree with previously reported data for long-wavelength longitudinal acoustic phonon and A1g optical phonon obtained from ultrafast time-resolved measurements. By combing the frequency dependent anharmonic phonon group velocities and lifetime, mode-wise thermal conductivities are predicted to reveal the contributions of heat carriers with different polarizations and wavelength.
Experimental Analysis of Nanofluid Slurry Through Rectangular Porous Channel
Authors: Ghaziani Navid O. , Hassanipour Fatemeh
Published: October 2013

One of the limitations in evolution of energy-efficient heat transfer fluids in industrial application is their low thermal conductivity. Among the emerging heat transfer technologies of today are fluid additives based on metallic nanoparticles. Previous studies show that Matalic nano particles increase the heat transfer rate by their thermal conductivity. This experimental study investigates the heat transfer behavior of nanofluid slurry through metal foam. Using suspending Aluminum Oxide nanoparticles (AL2O3) in fluid flowing through porous medium leads to have an even greater augmentation in heat transfer rate. Metal foams (porous media) enhance heat transfer rate not only by their high thermal conductivity and also by their mixing effect. When these two subjects come together even more interesting behaviors happen. This paper presents the result of heat transfer enhacment by slurry of metal nanoparticles in porous media in various of flow velocities, heat flux and porous media structures e.g. PPI and particle concentration of nanofluid.
On the Extraction of Pressure Fields From PIV Velocity Measurements in Turbines
Authors: Villegas Arturo , Diez F. Javier
Published: October 2013

In this study, the pressure field for a water turbine is derived from particle image velocimetry (PIV) measurements. Measurements are performed in a recirculating water channel facility. The PIV measurements include calculating the tangential and axial forces applied to the turbine by solving the integral momentum equation around the airfoil. The results are compared with the forces obtained from the Blade Element Momentum theory (BEMT). Forces are calculated by using three different methods. In the first method, the instantaneous and mean pressure fields are obtained from PIV velocity fields by solving the Poisson equation. The developed method can be applied to rectangular fields of view with any complex internal boundary such an airfoil. The boundary conditions are obtained from the Navier-Stokes momentum equations. A central finite difference approximation is applied to obtain velocities spatial gradients up to the second order. A forward difference approximation is applied to obtain the unsteady term (acceleration). In the second method, the pressure at the boundaries is determined by spatial integration of the pressure gradient using forward finite differences along the boundaries. The forces in the blade can be obtained using this method without the need to resolve the pressure field inside of the domain. In the third method, applicable only to incompressible, inviscid, irrotational, and steady flow, the pressure is calculated using the Bernoulli equation. This approximated pressure is known to be accurate far from the airfoil and outside of the wake for steady flows. This value is compared to the pressure obtained from the Poisson equation. Additionally, that pressure is used to solve for the force from the integral momentum equation on the blade. From the three methods proposed to solve for pressure and forces from PIV measurements, the first one, which is solved by using the Poisson equation, provides the best match to the BEM theory calculations. In the proposed methods, the pressure is calculated from a known PIV velocity field. On the other hand, in computational fluid dynamic (CFD) studies, the velocity is unknown. Thus, the proposed experimental calculations should be useful in those CFD studies.
Experimental Study of Critical Heat Flux and Heat Transfer Coefficient Enhancements in Pool Boiling Heat Transfer With Nanostructure Modified Active Nucleation Site and Contact Angle
Authors: Nolan Eric , Rioux Russell , Li Calvin Hong
Published: October 2013

An experimental study of nanostructure modified nucleation site density and contact angle that significantly enhances the Heat Transfer Coefficient (HTC) and the Critical Heat Flux (CHF) in pool boiling heat transfer of water on copper surfaces has been conducted. The nanostructures on copper surfaces have been created by an electrodeposition technique. It has been found that the nanostructured copper surfaces show an increase in CHF of up to 142% and an increase in HTC of 33% over that of a mirror-finished plain copper surface. Calculations for nucleation site density and active nucleation site diameter reveal a direct correlation between these factors and the HTC, as well as the CHF. More interestingly, a contact angle study on the tested surfaces shows that there is a connection between the contact angle reduction and CHF enhancement, which confirms the contact angle mechanism of CHF with experimental evidence.
Minichannels Cooling Using MWNT Fin Structures and Al2O3 Nanofluid
Authors: Tullius Jami Frances , Bayazitoglu Yildiz
Published: October 2013

Future innovations of electronics are bounded by the availability of effective cooling methods to remove heat that is generated. Micro- and minichannels, acting as heat exchangers, are effective in removing heat from small surfaces because of their large surface area to volume ratio [1]. Both micro pin finned structures [2,3] and nanofluids [4–6] have proven to provide significant enhancement in thermal performance in minichannels.
Modeling Strategies to Compute Natural Circulation Using CFD in a VHTR After a LOFA
Authors: Tung Yu-Hsin , Johnson Richard W. , Chieng Ching-Chang , Ferng Yuh-Ming
Published: October 2013

A prismatic gas-cooled very high temperature reactor (VHTR) is being developed under the next generation nuclear plant program (NGNP) of the U.S. Department of Energy, Office of Nuclear Energy. In the design of the prismatic VHTR, hexagonal shaped graphite blocks are drilled to allow insertion of fuel pins, made of compacted tristructural-isotropic (TRISO) fuel particles, and coolant channels for the helium coolant. One of the concerns for the reactor design is the effects of a loss of flow accident (LOFA) where the coolant circulators are lost for some reason, causing a loss of forced coolant flow through the core. In such an event, it is desired to know what happens to the (reduced) heat still being generated in the core and if it represents a problem for the fuel compacts, the graphite core or the reactor vessel (RV) walls. One of the mechanisms for the transport of heat out of the core is by the natural circulation of the coolant, which is still present. It is desired to know how much heat may be transported by natural circulation through the core and upwards to the top of the upper plenum.

It is beyond current capability for a computational fluid dynamics (CFD) analysis to perform a calculation on the whole RV with a sufficiently refined mesh to examine the full potential of natural circulation in the vessel. The present paper reports the investigation of several strategies to model the flow and heat transfer in the RV. It is found that it is necessary to employ representative geometries of the core to estimate the heat transfer. However, by taking advantage of global and local symmetries, a detailed estimate of the strength of the resulting natural circulation and the level of heat transfer to the top of the upper plenum is obtained.
A System Modeling Approach for Active Solar Heating and Cooling System With Phase Change Material (PCM) for Small Buildings
Authors: Ratnanandan Rajeevan , González Jorge E.
Published: October 2013

The paper presents a study of the performance of an active solar thermal heating and cooling system for small buildings. The work is motivated by the need for finding sustainable alternatives for building applications that are climate adaptable. The energy demand for heating and cooling needs in residential and light commercial buildings in mid-latitudes represent more than 50% of the energy consumed annually by these buildings. Solar thermal energy represents an untapped opportunity to address this challenge with sustainable solutions. Direct heating could be a source for space heating and hot water, and for heat operated cooling systems to provide space cooling. However, a key limitation in mainstreaming solar thermal for heating and cooling has been the size of thermal storage to implement related technologies. We address this issue by coupling a Phase Change Material (PCM) with an adsorption chiller and a radiant flooring system for year round solar thermal energy utilization in Northern climates. The adsorption chiller allows for chill water production driven by low temperature solar thermal energy for summer cooling, and low temperature radiant heating provides for space heating in winter conditions, while hot water demand is supplied year round. These active systems are operated by high performance solar thermal collectors. The PCM has been selected to match temperatures requirements of the adsorption chiller, and the tank was designed to provide three levels of temperatures for all applications; cooling, heating, and hot water. The material selection is paraffin sandwiched with a graphite matrix to increase the conductivity.

The specific objective of the preset work is to provide a system optimization of this active system. The system is represented by a series of mathematical models for each component; PCM tank with heat exchangers, the adsorption machine, the radiant floor, and the solar thermal collectors (Evacuated tubular collectors). The PCM modeling allows for sensible heating, phase change process, and superheating. Parametric simulations are conducted for a defined small building in different locations in US with the objective of defining design parameters for; optimal solar collector array, sizing of the PCM tank, and performance of the adsorption machine and radiant heating system. The monthly and annual solar fractions of the system are also reported.
A New Control Strategy to Improve the Ground Source Heat Pump’s Efficiency With a Recycled Product
Authors: Rezaei-Bazkiaei Amir , Dehghan-Niri Ehsan , Kolahdouz Ebrahim M. , Dargush Gary F. , Weber A. Scott
Published: October 2013

Despite numerous efforts to impose control measures on the heat pump side of Ground Source Heat Pump (GSHP) systems, there has been little thought into the potential of control on the ground characteristics. This is perhaps because of a predisposition to believe that ground related works usually are associated with extra capital investment that makes any modification less favorable than making changes to the heat pump unit. An effective control strategy with a non-homogeneous soil profile for the ground side of horizontal GSHPs was investigated in this research. The model incorporates the effects of a variety of surface energy fluxes to provide an accurate estimate of the ground thermal regime. The developed model was utilized successfully in conjunction with the MATLAB Genetic Algorithm (GA) toolbox to obtain the optimized operational parameters for a GSHP in a cold climate condition (Buffalo, NY). A properly sized and engineered non-homogeneous soil profile demonstrated the potential to boost the capacity of GSHP systems to a significant level. The potential benefits of a recycled product of tire industry, Tire Derived Aggregate (TDA), as an insulation blanket was assessed via the optimization algorithm. TDA was demonstrated to be effective in heating mode in a cold climate environment by increasing the energy extraction rates from the ground by about 15% annual. The annual percentage increase in energy dissipation rate to the ground, in cooling season, with TDA blanket was 7.6%. The results are suggestive of the beneficial application of a layered system to increase the performance of GSHPs. A shift in design perspective toward consideration of more control strategies for the ground pipe side of GSHPs is suggested based on the model results.
Dynamics of Air and Wall Temperatures in Multiroom Buildings
Authors: Sen Mihir , Amegashie Ishmael , Cecconi Emilio , Antsaklis Panos
Published: October 2013

Temperatures have been recorded every five minutes in a number of rooms in a student dormitory. The experimental data are presented as an example of room temperature dynamics in a large multi-room building. Statistical analyses of the data have been carried out to provide auto-correlations of individual room temperatures, its power spectral density, histogram, and the cross-correlations between the temperatures in neighboring rooms. A fairly complicated behavior is observed. A parallel, simplified mathematical model is set up for air and wall temperatures in multiple rooms to explain the temperature dynamics. Each room has an independent heater that switches on and off at certain lower and upper limits, respectively. The governing equations are based on energy balances with heat exchanges occurring between the air in a room and the walls surrounding it, and with the exterior. The instants at which heaters switch on or off are determined by the temperatures, leading thus to a non-linear set of equations. The governing equations are non-dimensionalized to provide the significant non-dimensional groups of the system: there are two which characterize the problem. Limiting solutions for large and small values of these groups provide physical explanation for the effect of the walls. Numerical solutions of this set of first-order ordinary differential equations are easily obtained, and examples of this are shown. The results show that there are still other physical effects to be considered before theory and experiments can be reasonably compared.
Incremental Digital Volume Correlation for Large Deformation Measurement of PMI Foam in Compression
Authors: Hu Zhenxing , Luo Huiyang , Young William , Lu Hongbing
Published: October 2013

We implemented an incremental digital volume correlation (DVC) technique for large nonlinear deformation measurements, and apply the technique for cell deformations in a closed-cell polymethacrylimide (PMI). The DVC technique previously reported in literature has used the natural state as the reference image to calculate all stages of deformation. It does not converge when large nonlinear deformations are involved, as in the case of PMI foam in compression. In this paper, we implemented an incremental DVC technique by updating the reference volume image at the last former stage, in order to achieve the correlation. The incremental DVC technique is verified using simulated rotation test. An unconfined uniaxial compression experiment on a PMI foam was conducted and in-situ microtomography was acquired. The microstructural evolution of the PMI foam was captured during compression; the displacement fields are obtained using the incremental DVC method. The incremental DVC technique can be used to evaluate the microstructural evolution of materials under large nonlinear deformations on images obtained from different 3D imaging techniques, including those from x-ray, laser, ultrasound, magnetic resonance, and neutron sources.
Large Eddy Simulation of the Flow Over a Flat Plate at Small Incidence Angle With an Advective Sub-Grid Model
Authors: Sampaio L. E. B. , Rezende A. L. T. , Nieckele A. O.
Published: October 2013

Understanding the flow around thin flat plate at shallow incidence can help in the design of airfoils and sails, as well as flexible wing-based micro air vehicles. Although the geometry is simple, the flow is very complex.

In the present work, the flow field is determined with a LES advective subgrid-scale model (f-LES) which directly adds a force to the original equation, instead of a divergent of a subgrid tensor. This force is built to have an advective nature and to damp only the very smallest modes supported by the spatial discretization. The f-LES model was implemented in the open source code OpenFOAM®. The model prediction was evaluated by examining the decaying of homogeneous isotropic turbulence, and comparing with the traditional Smagorinsky and Dynamic Smagorinsky models.

The flow over a plate with Reynolds number equal to 2.13 × 105 and angle of attack of 1° was analyzed. Average velocity and pressure, as well as, second order statistics were compared with available experimental data, presenting reasonable agreement. Coherent structures are visualized, as well as the evolution vortex tubes.
Correcting radiation survey data to account for increased leakage during intensity modulated radiotherapy treatments
Authors: Kairn T. , Crowe S. B. , Trapp J. V.
Published: October 2013

Purpose:

Intensity modulated radiotherapy (IMRT) treatments require more beam‐on time and produce more linac head leakage to deliver similar doses to conventional, unmodulated, radiotherapy treatments. It is necessary to take this increased leakage into account when evaluating the results of radiation surveys around bunkers that are, or will be, used for IMRT. The recommended procedure of applying a monitor‐unit based workload correction factor to secondary barrier survey measurements, to account for this increased leakage when evaluating radiation survey measurements around IMRT bunkers, can lead to potentially costly overestimation of the required barrier thickness. This study aims to provide initial guidance on the validity of reducing the value of the correction factor when applied to different radiation barriers (primary barriers, doors, maze walls, and other walls) by evaluating three different bunker designs.

Methods:

Radiation survey measurements of primary, scattered, and leakage radiation were obtained at each of five survey points around each of three different radiotherapy bunkers and the contribution of leakage to the total measured radiation dose at each point was evaluated. Measurements at each survey point were made with the linac gantry set to 12 equidistant positions from 0° to 330°, to assess the effects of radiation beam direction on the results.

Results:

For all three bunker designs, less than 0.5% of dose measured at and alongside the primary barriers, less than 25% of the dose measured outside the bunker doors and up to 100% of the dose measured outside other secondary barriers was found to be caused by linac head leakage.

Conclusions:

Results of this study suggest that IMRT workload corrections are unnecessary, for survey measurements made at and alongside primary barriers. Use of reduced IMRT workload correction factors is recommended when evaluating survey measurements around a bunker door, provided that a subset of the measurements used in this study are repeated for the bunker in question. Reduction of the correction factor for other secondary barrier survey measurements is not recommended unless the contribution from leakage is separately evaluated.
Vacuum Energy and Inflation: 3. Newtonian Cosmology & GR
Authors: Huggins Elisha
Published: October 2013

This is paper #3 in a series of four papers on vacuum energy and inflation. In paper #1 we discussed an example of what we have been calling vacuum energy.1 It is an energy with negative pressure whose energy density remains constant in an expanding space. We showed that an energy density with these properties exists between the plates of a parallel plate capacitor. In paper #2 we discussed a model universe consisting of vacuum energy with a few galaxies added in as markers, so that we could observe the expansion of space.2 We discovered that such a galaxy involved a huge release of gravitational potential energy, and we could easily calculate the rate of the Hubble expansion. Throughout, we used standard notation found in introductory physics, so that students could develop an intuition for the new concepts involved in an expanding space. In this, paper #3, we will use the notation of a scale factor a(t) to obtain equations similar to those derived from general relativity.
Archimedes in Action
Authors: Vo Phong T.
Published: October 2013

Hands-on learning is very effective in teaching physical concepts to students. Applying the principles they learn to a real-life situation, students are more likely to retain this knowledge, especially when it is presented in a stimulating format. With this in mind, we present here a high school physics project in which students apply basic hydrostatics to construct corrugated cardboard boats capable of supporting two individuals across the length of a high school pool.
Efficacy of Adefovir-Based Combination Therapy for Patients with Lamivudine- and Entecavir-Resistant Chronic Hepatitis B Virus Infection
Authors: Lee Yun Bin , Lee Jeong-Hoon , Choi Won-mook , Cho Young Youn , Yoo Jeong-ju , Lee Minjong , Lee Dong Hyeon , Cho Yuri , Yu Su Jong , Kim Yoon Jun , Yoon Jung-Hwan , Kim Chung Yong , Lee Hyo-Suk
Published: October 2013

Treatment strategies for entecavir (ETV)-resistant chronic hepatitis B (CHB) patients are not yet well established. The aim of this study was to evaluate overall antiviral efficacy and to compare the efficacy of combination therapy with adefovir (ADV) plus nucleoside analogues (lamivudine [LAM], telbivudine [LdT], or ETV) in patients infected with LAM- and ETV-resistant hepatitis B virus (HBV) variants. Virologic, biochemical, and serologic responses during combination therapy with ADV plus nucleoside analogues were assessed. Propensity score analysis was used to select a matched group of patients for the comparison of rescue therapy regimens. A total of 67 consecutive patients were analyzed. Complete virologic suppression was achieved in 27 patients. The overall cumulative incidence of complete virologic suppression at month 24 was 47.4%: 44.3% in the LAM or LdT plus ADV group and 51.4% in the group given ETV and ADV. There was no significant difference between these two groups (P= 0.234). The cumulative incidences of complete virologic suppression were still comparable between the two groups selected and matched using the propensity score model (P= 0.419). Virologic breakthrough was observed in 9 patients, and rtA181V substitution was newly detected in one patient. Hepatitis B e antigen (HBeAg) negativity and lower baseline HBV DNA level were associated with complete virologic suppression in univariate analysis. In multivariate analysis, lower baseline HBV DNA level remained an independent predictor. In conclusion, combination therapy with ADV plus nucleoside analogues fails to show sufficient antiviral efficacy in CHB patients with resistance to both LAM and ETV. Further study is warranted to evaluate the efficacy of a more potent tenofovir-based regimen in such patients.
The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials
Authors: Lauersen Jeppe Bo , Bertelsen Ditte Marie , Andersen Lars Bo
Published: October 2013

Background

Physical activity is important in both prevention and treatment of many common diseases, but sports injuries can pose serious problems.

Objective

To determine whether physical activity exercises can reduce sports injuries and perform stratified analyses of strength training, stretching, proprioception and combinations of these, and provide separate acute and overuse injury estimates.

Material and methods

PubMed, EMBASE, Web of Science and SPORTDiscus were searched and yielded 3462 results. Two independent authors selected relevant randomised, controlled trials and quality assessments were conducted by all authors of this paper using the Cochrane collaboration domain-based quality assessment tool. Twelve studies that neglected to account for clustering effects were adjusted. Quantitative analyses were performed in STATA V.12 and sensitivity analysed by intention-to-treat. Heterogeneity (I2) and publication bias (Harbord's small-study effects) were formally tested.

Results

25 trials, including 26 610 participants with 3464 injuries, were analysed. The overall effect estimate on injury prevention was heterogeneous. Stratified exposure analyses proved no beneficial effect for stretching (RR 0.963 (0.846–1.095)), whereas studies with multiple exposures (RR 0.655 (0.520–0.826)), proprioception training (RR 0.550 (0.347–0.869)), and strength training (RR 0.315 (0.207–0.480)) showed a tendency towards increasing effect. Both acute injuries (RR 0.647 (0.502–0.836)) and overuse injuries (RR 0.527 (0.373–0.746)) could be reduced by physical activity programmes. Intention-to-treat sensitivity analyses consistently revealed even more robust effect estimates.

Conclusions

Despite a few outlying studies, consistently favourable estimates were obtained for all injury prevention measures except for stretching. Strength training reduced sports injuries to less than 1/3 and overuse injuries could be almost halved.
Age-related variation in sexual behaviours among heterosexual men residing in Brazil, Mexico and the USA
Authors: August Euna M , Daley Ellen , Kromrey Jeffrey , Baldwin Julie , Romero-Daza Nancy , Salmeron Jorge , Lazcano-Ponce Eduardo , Villa Luisa L , Bryant Carol A , Giuliano Anna R
Published: October 2013

Objective

To compare the prevalence of demographic characteristics and sexual behaviours across age groups and to estimate their significance in predicting sexual risk factors by age cohort.

Methods

This cohort study examined sexually transmitted infection (STI) prevalence among heterosexual men in Brazil, Mexico and the USA (N=3047). Participants completed a sexual risk factor questionnaire and were tested for chlamydia, gonorrhoea, syphilis and genital herpes. We examined sexual risk in the study population through a composite measure of STI positivity by age cohort (young: 18–30 years; middle-aged: 31–44 years; older: 45–70 years). Multivariable logistic regression models were used to generate adjusted odds ratios (AORs) and 95% confidence intervals (CIs).

Results

We found that STI positivity varied significantly by age group among heterosexual men by a number of covariates. In younger men, having more advanced education had a protective effect (16 years: AOR=0.37, 95% CI 0.15– 0.92), whereas higher numbers of sexual partners elevated the risk for STIs (20–49 partners: AOR=2.06, 95% CI 1.04–4.06; ≥50 partners: AOR=4.33, 95% CI 1.74–10.76). Middle-aged men who were black (AOR=1.64, 95% CI 1.10–2.42) and divorced/separated/widowed (AOR=1.91, 95% CI 1.21–3.02) had an increased risk for a positive STI test. Among older men, a younger age at first vaginal sexual encounter (AOR=3.75, 95% CI 1.45–9.74) and a history of exchanging sex for money or drugs heightened STI risk (AOR=2.30, 95% CI 1.0–5.04).

Conclusions

These findings demonstrate that age-related life experiences among heterosexual men influence sexual risk and STI transmission. This topic warrants further investigation to support the development and implementation of targeted interventions that may potentially reduce adverse sexual health outcomes.
Prospects for coitally-dependent hormonal contraception: perspectives from women in urban Kenya and Nigeria
Authors: Chin-Quee Dawn , L'Engle Kelly , Otterness Conrad
Published: October 2013

Introduction

Emergency contraceptive pills (ECPs) were developed and marketed with the emergency aspect firmly in mind, but research and anecdotal evidence indicate that some women use them as a form of regular contraception, spurring efforts in the reproductive health community to explore the development of a coitally-dependent oral contraceptive pill.

Methods

We asked women of reproductive age in Nairobi, Kenya and Lagos, Nigeria how likely they would be to use a hypothetical pericoital pill and why.

Results

Bivariate logistic regressions indicated that women aged 18–35 years, with secondary education or higher, and who had ever used condoms or short-acting methods, were more likely to say that they would use this hypothetical pill. Women who had ever used a family planning method or ECPs were also more likely to say they would use this pill. The likely adopters reported that they would use the pericoital method if it prevented pregnancy with little or no health problems and was convenient and easy to use.

Conclusion

The findings suggest that should a safe and effective pericoital hormonal pill become available then a significant number of women would adopt this method.
EFFECTS OF TANGENT OPERATORS ON PREDICTION ACCURACY OF MESO-MECHANICAL CONSTITUTIVE MODEL OF ELASTO-PLASTIC COMPOSITES
Authors: GUO S. J. , KANG G. Z. , ZHANG J. , KAN Q. H.
Published: October 2013

With a newly developed homogenization cyclic constitutive model of particle reinforced metal matrix composites [Guo et al. (2011)], the effects of tangent operators, i.e., continuum and algorithmic tangent operators [defined by Doghri and Ouaar (2003)] on the accuracy of the developed meso-mechanical constitutive model to predict the monotonic tensile and uniaxial ratchetting deformations of SiC P /6061 Al composites were investigated in this work. The predictions were obtained by the developed model with the choices of different tangent operators and various magnitudes of load increments. Comparison of prediction accuracy and necessary error analysis on the results obtained by different tangent operators were conducted. It is shown that: the stress or strain difference in each load increment and produced by using different tangent operators will accumulate step by step; accurate prediction should be obtained by employing a load increment small enough, especially when the algorithmic tangent operator is used in predicting the uniaxial ratchetting of the composites.
A NOVEL METHOD BASED ON THE TIKHONOV FUNCTIONAL FOR NON-NEGATIVE SOLUTION OF A SYSTEM OF LINEAR EQUATIONS WITH NON-NEGATIVE COEFFICIENTS
Authors: ILYA FIKS
Published: October 2013

We propose a novel method for a solution of a system of linear equations with the non-negativity condition. The method is based on the Tikhonov functional and has better accuracy and stability than other well-known algorithms.
SPECTRAL NORMS OF CIRCULANT-TYPE MATRICES WITH BINOMIAL COEFFICIENTS AND HARMONIC NUMBERS
Authors: ZHOU JIANWEI , JIANG ZHAOLIN
Published: October 2013

In this paper, we investigate spectral norms for circulant-type matrices, including circulant, skew-circulant, and g-circulant matrices. The entries are product of Binomial coefficients with Harmonic numbers. We obtain explicit identities for these spectral norms. Employing these approaches, we list some numerical tests to verify our results.
Web media semantic concept retrieval via tag removal and model fusion
Authors: Chen Chao , Zhu Qiusha , Lin Lin , Shyu Mei-Ling
Published: October 2013

Multimedia data on social websites contain rich semantics and are often accompanied with user-defined tags. To enhance Web media semantic concept retrieval, the fusion of tag-based and content-based models can be used, though it is very challenging. In this article, a novel semantic concept retrieval framework that incorporates tag removal and model fusion is proposed to tackle such a challenge. Tags with useful information can facilitate media search, but they are often imprecise, which makes it important to apply noisy tag removal (by deleting uncorrelated tags) to improve the performance of semantic concept retrieval. Therefore, a multiple correspondence analysis (MCA)-based tag removal algorithm is proposed, which utilizes MCA's ability to capture the relationships among nominal features and identify representative and discriminative tags holding strong correlations with the target semantic concepts. To further improve the retrieval performance, a novel model fusion method is also proposed to combine ranking scores from both tag-based and content-based models, where the adjustment of ranking scores, the reliability of models, and the correlations between the intervals divided on the ranking scores and the semantic concepts are all considered. Comparative results with extensive experiments on the NUS-WIDE-LITE as well as the NUS-WIDE-270K benchmark datasets with 81 semantic concepts show that the proposed framework outperforms baseline results and the other comparison methods with each component being evaluated separately.
Dealing with uncertainty
Authors: Wolf Hannes , Herrmann Klaus , Rothermel Kurt
Published: October 2013

Processes in the healthcare domain are characterized by coarsely predefined recurring procedures that are flexibly adapted by the personnel to suite-specific situations. In this setting, a workflow management system that gives guidance and documents the personnel's actions can lead to a higher quality of care, fewer mistakes, and higher efficiency. However, most existing workflow management systems enforce rigid inflexible workflows and rely on direct manual input. Both are inadequate for healthcare processes. In particular, direct manual input is not possible in most cases since (1) it would distract the personnel even in critical situations and (2) it would violate fundamental hygiene principles by requiring disinfected doctors and nurses to touch input devices. The solution could be activity recognition systems that use sensor data (e.g., audio and acceleration data) to infer the current activities by the personnel and provide input to a workflow (e.g., informing it that a certain activity is finished now). However, state-of-the-art activity recognition technologies have difficulties in providing reliable information.

We describe a comprehensive framework tailored for flexible human-centric healthcare processes that improves the reliability of activity recognition data. We present a set of mechanisms that exploit the application knowledge encoded in workflows in order to reduce the uncertainty of this data, thus enabling unobtrusive robust healthcare workflows. We evaluate our work based on a real-world case study and show that the robustness of unobtrusive healthcare workflows can be increased to an absolute value of up to 91% (compared to only 12% with a classical workflow system). This is a major breakthrough that paves the way towards future IT-enabled healthcare systems.
Spermatogonial Stem Cell Self-Renewal and Development
Authors: Kanatsu-Shinohara Mito , Shinohara Takashi
Published: October 2013

Spermatogenesis originates from spermatogonial stem cells (SSCs). Development of the spermatogonial transplantation technique in 1994 provided the first functional assay to characterize SSCs. In 2000, glial cell line–derived neurotrophic factor was identified as a SSC self-renewal factor. This discovery not only provided a clue to understand SSC self-renewing mechanisms but also made it possible to derive germline stem (GS) cell cultures in 2003. In vitro culture of GS cells demonstrated their potential pluripotency and their utility in germline modification. However, in vivo SSC analyses have challenged the traditional concept of SSC self-renewal and have revealed their relationship with the microenvironment. An improved understanding of SSC self-renewal through functional assays promises to uncover fundamental principles of stem cell biology and will enable us to use these cells for applications in animal transgenesis and medicine.
Developing Mobile‐ and BIM‐Based Integrated Visual Facility Maintenance Management System
Authors: Lin Yu-Cheng , Su Yu-Chih
Published: October 2013

Facility maintenance management (FMM) has become an important topic for research on the operation phase of the construction life cycle. Managing FMM effectively is extremely difficult owing to various factors and environments. One of the difficulties is the performance of 2D graphics when depicting maintenance service. Building information modeling (BIM) uses precise geometry and relevant data to support the maintenance service of facilities depicted in 3D object‐oriented CAD. This paper proposes a new and practical methodology with application to FMM using BIM technology. Using BIM technology, this study proposes a BIM‐based facility maintenance management (BIMFMM) system for maintenance staff in the operation and maintenance phase. The BIMFMM system is then applied in selected case study of a commercial building project in Taiwan to verify the proposed methodology and demonstrate its effectiveness in FMM practice. Using the BIMFMM system, maintenance staff can access and review 3D BIM models for updating related maintenance records in a digital format. Moreover, this study presents a generic system architecture and its implementation. The combined results demonstrate that a BIMFMM‐like system can be an effective visual FMM tool.
A Massive Posterior Neck Mass: Lipoma or Something More Sinister?
Authors: Ryan Matthew F. , Allen Brandon
Published: October 2013

Lipomas are slow-growing benign soft-tissue tumors which are typically asymptomatic and occur in approximately 1% of the population. A lipoma is considered to be of excessive size when it is greater than 10 cm in length (in any dimension) or weighs over 1000 g (Kransdorf (1995)). We describe a case of a man presenting with a giant posterior neck mass which greatly reduced the sagittal range of cervical spine. A discussion of the pathophysiology of lipomas and a literature review regarding giant lipomas versus malignancy follows.
Treatment of Palatal Myoclonus with Botulinum Toxin Injection
Authors: Anis Mursalin M. , Pollak Natasha
Published: October 2013

Palatal myoclonus is a rare cause of pulsatile tinnitus in patients presenting to the otolaryngology office. Rhythmic involuntary contractions of the palatal muscles produce the pulsatile tinnitus in these patients. Treatment of this benign but distressing condition with anxiolytics, anticonvulsants, and surgery has been largely unsuccessful. A few investigators have obtained promising results with botulinum toxin injection into the palatal muscles. We present a patient with palatal myoclonus who failed conservative treatment with anxiolytics. Unilateral injection of botulinum toxin into her tensor veli palatini muscle under electromyographic guidance resolved pulsatile tinnitus in her ipsilateral ear and unmasked pulsatile tinnitus in the contralateral ear. A novel method of following transient postinjection symptoms using a diary is presented in this study. Botulinum toxin dose must be titrated to achieve optimal results in each individual patient, analogous to titrations done for spasmodic dysphonia. Knowledge of the temporal onset of postinjection side effects and symptomatic relief may aid physicians in dose titration and surveillance. We present suggestions on titrating the botulinum toxin dose to optimal levels. A review of the literature on the use of botulinum toxin for palatal myoclonus and some common complications are discussed.
Ethanol Extract ofUlmus pumilaRoot Bark Inhibits Clinically Isolated Antibiotic-Resistant Bacteria
Authors: You Yong-Ouk , Choi Na-Young , Kim Kang-Ju
Published: October 2013

In this study, root bark ofUlmus pumila(U. pumila) was extracted with ethanol, and then the antimicrobial effects were tested on clinically isolated 12 MRSA strains and 1 standard MRSA strain.U. pumilashowed antibacterial activities against all MRSA strains. Minimum inhibitory concentration (MIC) ofU. pumilaroot bark against all MRSA strains revealed a range from 125 to 250 μg/mL. These results may provide the scientific basis on whichU. pumilaroot bark has traditionally been used against infectious diseases in Korea. In real-time PCR analysis, the sub-MIC (64–125 μg/mL) concentrations ofU. pumilaroot bark extract showed the inhibition of the genetic expressions of virulence factors such asmecA,sea,agrA, andsarAin standard MRSA. Phytochemical analyses ofU. pumilaroot bark showed relatively strong presence of phenolics, steroids, and terpenoids. These results suggest that the ethanol extract ofU. pumilaroot bark may have antibacterial activity against MRSA, which may be related to the phytochemicals such as phenolics, steroids, and terpenoids. Further studies are needed to determine the active constituents ofU. pumilaroot bark responsible for such biomolecular activities.
Hankel Determinant for -Valent Alpha-Convex Functions
Authors: Singh Gagandeep , Mehrok B. S.
Published: October 2013

The objective of the present paper is to obtain the sharp upper bound of for p-valent α-convex functions of the form in the unit disc .
Abstract Semilinear Evolution Equations with Convex-Power Condensing Operators
Authors: Zhu Lanping , Huang Qianglian , Li Gang
Published: October 2013

By using the techniques of convex-power condensing operators and fixed point theorems, we investigate the existence of mild solutions to nonlocal impulsive semilinear differential equations. Two examples are also given to illustrate our main results.
Initial Systematic Investigations of the Landscape of Low-Layer NAHE Variation Extensions
Authors: Renner Timothy , Greenwald Jared , Moore Douglas , Cleaver Gerald
Published: October 2013

The discovery that the number of physically consistent string vacua is on the order of 10500 has prompted several statistical studies of string phenomenology. Focusing on the Weakly Coupled Free Fermionic String formalism, we present systematic extensions of a variation on the NAHE (Nanopoulos, Antoniadis, Hagelin, Ellis) set of basis vectors. This variation is more conducive to the production of “mirrored” models, in which the observable and hidden sector gauge groups (and possibly matter content) are identical. This study is parallel to the extensions of the NAHE set itself and presents statistics related to similar model properties. Statistical coupling between specific gauge groups and spacetime supersymmetry is also examined. Finally, a model with completely mirrored gauge groups is discussed. It is found that the region of the landscape explored generates no physically realistic models due to a lack of three net chiral generations.
Fatal Huge Left Free Wall Ventricular Rupture after Acute Posterior Myocardial Infarction
Authors: Formica Francesco , Mariani Silvia , Ferro Orazio , Paolini Giovanni
Published: October 2013

A 77-year-old man, with a recent history of an acute inferior myocardial infarction, was referred to our hospital with echocardiographic and clinical signs of left ventricular free wall rupture (LVFWR). The intraoperative finding demonstrated a huge double LVFWR. The inferoposterior wall was dramatically destroyed without any possibility to repair.
UPLC-TOF-MS Characterization and Identification of Bioactive Iridoids inCornus masFruit
Authors: Deng Shixin , West Brett J. , Jensen C. Jarakae
Published: October 2013

Cornus masL. is indigenous to Europe and parts of Asia. AlthoughCornusis widely considered to be an iridoid rich genera, only two iridoids have been previously found in this plant. The lack of information on taxonomically and biologically active iridoids prompted us to develop and optimize an analytical method for characterization of additional phytochemicals inC. masfruit. An ultra performance liquid chromatography (UPLC) coupled with photodiode array spectrophotometry (PDA) and electrospray time-of-flight mass spectrometry (ESI-TOF-MS) was employed and mass parameters were optimized. Identification was made by elucidating the mass spectral data and further confirmed by comparing retention times and UV spectra of target peaks with those of reference compounds. Primary DNA damage and antigenotoxicity tests inE. coliPQ37 were used to screen the iridoids for biological activity. As a result, ten phytochemicals were identified, including iridoids loganic acid, loganin, sweroside, and cornuside. Nine of these were reported for the first time fromC. masfruit. The iridoids did not induce SOS repair of DNA, indicating a lack of genotoxic activity inE. coliPQ37. However, loganin, sweroside, and cornuside did reduce the amount of DNA damage caused by 4-nitroquinoline 1-oxide, suggesting potential antigenotoxic activity.
Bidirectional Power Performance of a Tidal Unit with Unilateral and Double Guide Vanes
Authors: Yang Chunxia , Zheng Yuan , Zhou Daqing , Ge Xinfeng , Li Lingyu
Published: October 2013

To improve the bidirectional power performance of a tidal unit, two designs were investigated. The use of unilateral or double guide vanes in a tubular tidal unit influences the performance of the hydraulic unit. Based on the N-S equations and the RNG k-ε turbulence model, the SIMPLEC algorithm was used for 3D steady-state numerical simulation of the entire turbine flow passage with unilateral and double guide vanes. The internal flow condition under positive and reverse power generation conditions was also analyzed. At the same time, the turbine, with a runner 1.6 m in diameter, was scaled down to 0.35 m diameter for model tests. The model tests were based on a multifunction hydromechanical test bench at Hohai University. The water head, discharge, and torque of the tubular turbine were, respectively, tested using a pressure difference sensor, electromagnetic flow meter, and torque meter under different guide-vane openings. The results show that turbine efficiency in the model test is slightly lower than that predicted by numerical simulation under the same conditions. However, the difference is not large. With double side guide vanes, although the efficiency of positive power generation decreased, the efficiency of reverse power generation is greatly improved.
Out of Asia: An Allopatric Model for the Evolution of the Domestic Dog
Authors: Braude Stan , Gladman Justin
Published: October 2013

The domestication of the dog has been a ripe area of evolutionary speculation for more than 150 years. A wolf ancestry and probable East Asian origin of domestication are now widely accepted. We offer a new allopatric hypothesis for the domestication of dogs that recognizes the importance of isolation in the speciation of the dog from the wolf. Although sympatric isolation during domestication of many other species would not have been problematic, it has always been difficult to keep dogs from breeding with wild canids. Furthermore, wild canids readily hybridize with one another. This would have made it very difficult for an early domestic dog lineage to diverge from the wolf and to evolve into the morphologically, developmentally, and behaviorally distinct species that we recognize today. Our allopatric model is consistent with two subhypotheses: isolation when tamer scavenger wolves followed humans south and away from hunting populations of wolves or isolation when climate forced humans and tamer scavenger wolves into isolated refugia.