bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Life Prediction Method of Turbine Blade Using the Theory of Critical Distance
Authors: Nakahara Tetsuya , Ueda Yusuke , Nakamura Hiroshi
Published: December 2013

Gas turbine blades mounted dovetail root are subjected to high centrifugal loads and gas forces. This situation causes low cycle fatigue (LCF). Recently, rotating speed and temperature of turbine rotor become higher in order to improve engine performance. To achieve this, it is required to evaluate accurate turbine blade’s LCF life of the contact surface between the blade dovetail root and the disk. However, the estimated blade lives using the peak stress calculated by finite element analysis (FEA) are much shorter than actual life because the stress at contact surface is excessively high. As a result, the blades are designed conservative and the blade’s weight tends to be heavy. Therefore, a more accurate evaluation methodology needs to be established.

This study investigates the method to estimate the fatigue strength of dovetail using the theory of critical distance. The theory assumes that fatigue failures would occur due to the representative stress within a specific distance from stress concentration point. Fatigue tests and FEA for the turbine blade dovetail were conducted respectively in this research. The tests were carried out using single crystal nickel-based turbine blades at 600 °C and the fracture lives of dovetail were obtained. FEA was conducted to obtain the stress distributions at dovetail contact surface under testing condition. In this study, the critical distances of the single crystal nickel based alloy were obtained from the notched bar fatigue tests and FEA. Using these results and the theory of critical distance, fatigue lives of dovetail were obtained more accurately.
Thrust Control of Small Turbojet Engines Using Fuzzy Logic: Design and Experimental Validation
Authors: Amirante Riccardo , Catalano Luciano Andrea , Tamburrano Paolo
Published: December 2013

The aim of this paper is to propose an effective technique which employs a proportional-integral Fuzzy logic controller for the thrust regulation of small scale turbojet engines, capable of ensuring high performance in terms of response speed, precision and stability. Fuzzy rules have been chosen by logical deduction and some specific parameters of the closed loop control have been optimized using a numerical simulator, so as to achieve rapidity and stability of response, as well as absence of overshoots. The proposed Fuzzy logic controller has been tested on the Pegasus MK3 microturbine: the high response speed and precision of the proposed thrust control, revealed by the simulations, have been confirmed by several experimental tests with step response. Its stability has been demonstrated by means of the frequency response analysis of the system.

The proposed thrust control technique has general validity and can be applied to any small-scale turbojet engine, as well as to microturbines for electricity production, provided that thrust being substituted with the net mechanical power.
A Computational Investigation of Syngas Substitution Effects on the Combustion Characteristics for a Micro Gas Turbine
Authors: Liu Chi-Rong , Shih Hsin-Yi
Published: December 2013

The aim of this study is to investigate the effects of syngas substitution on combustion characteristics for a micro gas turbine. For syngas combustion, the ratio of hydrogen and carbon monoxide is varied depending on the process techniques and it could be critical for gas turbine combustion applications. The combustion characteristics of syngas are quite different from natural gas, for example, the flame speed of hydrogen is higher than that of natural gas, but the flame speed of carbon monoxide is lower. In order to understand the performance differences between syngas fuel and natural gas, the combustion and emission characteristics of a can type combustor were investigated with model simulations using the commercial code STAR-CD, where a three-dimensional compressible k-ε model for turbulent flows and presumed probability density function for chemical process between methane/syngas/air mixtures were constructed.

For the fuel injection velocity of 60 m/s and using hydrogen-rich (H2/CO = 80/20) syngas, the high temperature regions are separated and close to the sides of the combustor with some syngas fuel substituted for methane, but the high temperature zones move back to the core region of the combustor by substituting more syngas fuel. The CO2 and NOx emissions are decreased with 10% methane substituted by syngas, but increased with decreasing methane percentages. The detailed flame structures, distributions of flame temperature and flow velocity, and gas emissions of the combustor were presented and compared by using syngas composition and methane percentage of blended fuel mixture as the parameters. The exit temperature profiles and pattern factor were also discussed. Before syngas fuels are used as an alternative fuel for the micro gas turbine, further experimental testing are needed as the CFD modeling results provide a guidance for the improved designs of the combustor.
A New Model to Describe Yield Surface Distortion Based on the Baltov and Sawczuk’s Model
Authors: Nayebi A. , Rokhgireh H.
Published: December 2013

In the present study Baltov and Sawczuk’s yield surface model is modified to represent compatible results with experimental observations. The proposed yield surface is determined during tension-torsion loading by considering kinematic hardening model and monotonic loading paths. The experimental results represent the nosed and flattened region in the loading and reverse loading direction respectively. The nosed region is dominant in tension than in torsion. The cross-effect is negligible in the small plastic strain amount. The Baltov and Sawczuk’s yield surface has nosed and flattened regions in both loading and reversed loading directions for negative and positive added material parameter respectively. Thus the elliptic Baltov and Sawczuk’s yield surface is modified by changing the sign of this parameter continuously from loading to reverse loading direction and the needed relations of the new model are obtained. The new model was able to predict properly the shape of yield surface. The experimental results compare well with the new model yield surface distortion predictions.
Transient Resonance Passage With Respect to Friction
Authors: Bonhage Marius , Panning-von Scheidt Lars , Wallaschek Jörg , Richter Christoph
Published: December 2013

Gas and steam turbine applications are exposed to high vibration amplitudes. Friction damping elements are commonly used to prevent blades from fatigue failure. Most of the work done so far in this field is dealing with steady state vibration occurring due to harmonic excitation. Regarding the growing importance of renewable energy, the number of run-ups and rundowns in power plants is increasing continuously. Furthermore, also the speed of jet engines is changed regularly during operation. To give an analytical approach on how to calculate and create most effective friction damping during instationary excitation, this paper discusses the computation of transient nonlinear vibration. Following the description of a single-degree-of-freedom system comprising a friction contact, it is shown how to assemble the equation of motion using piecewise linear equations. An analytical ansatz is illustrated to solve the ODEs of the system. In the next step, two simple multi-body-systems are created that are coupled by a friction contact. To validate the analytical computation of the vibration response of the system, a numeric time integration of the system is done. The calculations are compared, and it is shown that the analytical ansatz is valid to compute the vibration of the system. Using the solution of the equation of motion of the multi-body-system, it is shown how the optimal friction damping of the system can be determined while varying important parameters like e.g. the normal force of the friction contact and the tangential stiffness of the contact model.
Review of Probabilistic Damage Tolerance Methodology for Hard Alpha Anomalies
Authors: Corran R. S. J. , Gorelik M. , Chawla D. , Mosset S. , Joinson M. B. , Harmon D. , Nissley D. , Murphy A. J. , Stillinger J. , Jacques K. W.
Published: December 2013

Following the Sioux City event in 1989, the aero gas turbine industry has collaborated with the FAA to develop a probabilistic damage tolerance approach to Hard Alpha melt anomalies in Titanium alloys used for life limited parts, mainly discs. The FAA has published a methodology in AC 33.14-1 by which Engine Manufacturers can determine if the combination of controls in the supply and inspection of the disc and the duty in the engine that the disc must sustain remain consistent with a committed reduction to the expected rate of Hard Alpha related events for all future engines. This methodology was based on the best understanding of the behavior of Hard Alpha anomalies current around 1996. Since that date, the knowledge surrounding melt anomalies in titanium has increased significantly, primarily due to research programs funded by the FAA but also by the collection of field and supply data on production parts in the intervening years. This report reviews the method of assessment described in the FAA AC33.14-1 in the light of later knowledge and over a decade of further supply and field experience. The main conclusions and recommendations from this study are discussed.
A Model to Predict the Stress Corrosion Cracking Growth Rate of the Metallic Materials
Authors: Jiao Guang Chen , Chen Gang , Wang Wei Zhe
Published: December 2013

A best-estimate assessment model was established to predict the entire life time of the material due to crack development and propagation in aggressive environment. Stress corrosion cracking (SCC) growth rate was modeled to investigate the influence of corrosion environment on SCC. Uncertainties with respect to material parameters, aggressive medium and mechanical loadings were taken into account. In addition, mean value estimation method (MVM) and monte carlo simulation method (MCS) were used to solve the established theoretical model. The studies demonstrated that the results obtained by using MVM reached agreement to those by using MCS. And the life time of the material due to the crack development and propagation in the aggressive environment was accurately predicted.
Unsteady Performance Prediction of a Single Entry Mixed Flow Turbine Using 1-D Gas Dynamic Code Extended With Meanline Model
Authors: Chiong Meng Soon , Rajoo Srithar , Romagnoli Alessandro , Martinez-Botas Ricardo
Published: December 2013

Turbochargers are widely regarded as one of the most promising enabling technology for engine downsizing, in the aim to achieve better specific fuel consumption, thermal efficiency and most importantly carbon reduction. The increasing demand for higher quality engine-turbocharger matching, leads to the development of computational models capable of predicting the unsteady behaviour of a turbocharger turbine when subjected to pulsating inlet flow. Due to the wide range of engine loads and speed variations, an automotive turbocharger turbine model must be able to render all the frequency range of a typical exhaust pulse flow. A purely one-dimensional (1-D) turbine model is capable of good unsteady swallowing capacity prediction, provided it is accurately validated. However, the unsteady turbine power evaluation still heavily relies on the quasi-steady assumption. On the other hand, meanline model is capable of resolving the turbine work output but it is limited to steady state flow due to its zero dimensional nature.

This paper explores an alternative methodology to realize turbine unsteady power prediction in 1-D by integrating these two independent modelling methods. A single entry mixed-flow turbine is first modelled using 1-D gas dynamic method to solve the unsteady flow propagation in turbine volute while the instantaneous turbine power is subsequently evaluated using a mean-line model. The key in the effectiveness of this methodology relies on the synchronization of the flow information with different time-scales. In addition to the turbine performance parameters, the common level of unsteadiness was also compared based on the Strouhal number evaluations. Comparison of the quasi-steady assumption using the experiment results was made in order to further understand the strength and weaknesses of corresponding method in unsteady turbine performance prediction. The outcomes of the simulation showed a good agreement in the shape and trend profile for the instantaneous turbine power. Meanwhile the predicted cycle-averaged value indicates a positive potential of the current turbine model to be expanded to a whole engine simulation after few minor improvements.
The Effects of Bearing Stiffness on Nonlinear Dynamic Behaviors of Multi-Mesh Gear Train
Authors: Shiau T. N. , Young T. H. , Chang J. R. , Huang K. H. , Wang C. R.
Published: December 2013

In this study, the nonlinear dynamic analysis of the multi-mesh gear train with elastic bearing effect is investigated. The gear system includes the three rigid shafts, two gear pairs and elastic bearings. The stiffness and damper coefficient of elastic bearing are considered. The equations of motion of nonlinear time-varying system are derived using Lagrangian approach. The Runge-Kutta Method is employed to determine the system dynamic behaviors including the bifurcation and chaotic motion. The results show that the periodic motion, quasi-periodical motion and chaos can be excited with the elastic bearing effect. Especially, the results also indicate the dynamic response will go from periodic to quasi-periodical before the chaotic motion when the bearing stiffness is increased.
Analysis of High Temperature Creep on the Nut Connection Components of a 600MW Supercritical Steam Turbine
Authors: Jiang P. N. , Wang W. Z. , Jiao G. C.
Published: December 2013

A model of the nut connection components of a 600MW supercritical steam turbine was established by finite element analysis to investigate the influence of creep on the nut connection components. Due to the complex structure and the multi-axial loadings, Cocks-Ashby coefficients were used to depict the multi-axial creep behavior. Multi-axial creep deformation criteria (MCDC) and multi-axial creep rupture criteria (MCRC) were used to assess the structure reliability. In addition, sealing performance of the nut connection components in the creep time of 2×105 hours was numerically investigated in terms of the contact pressure and the radial contact length. The results demonstrated that the creep strength of the nut connection components after 2×105 hours could maintain the safety operation of the nut connection components. The contact pressure distribution and the radial contact length in circumferential could prevent the leakage steam flow from the high pressure zone to the low pressure zone.
Experimental and Numerical Validation of Conical Strainer Fluid/Structural Performance Model
Authors: Carlomagno M. , Rossin S. , Delvecchio M. , Anichini A.
Published: December 2013

Temporary conical strainers are widely employed in the Oil & Gas industry as filtering devices in the Centrifugal Compressors suction line. They protect compressor stages from the ingestion of foreign objects whether coming from dirty process gas or left in the pipeline after its construction. Very few literature and research papers are available on the fluid dynamic and structural performance of conical strainers. The purpose of this work is to plug this gap by the definition of a theoretical-experimental model for the characterization of the pressure drop and mechanical resistance of these devices. Starting from the definition of the main fluid dynamics and geometric variables which influence the performances, an experimental campaign has been performed in order to derive the relationship governing the pressure drop behavior. The model efficacy has been confirmed by a CFD analysis, which also allowed a qualitative insight review into the dynamics of velocity and turbulence intensity fields. Further tests have been performed in order to validate the model at off-design points. As far as the structural analysis is concerned, several FEM models and DOE techniques have been implemented in order to define relationships for bust pressure computation and feasible design improvements with respect to the current state of the art. Besides fluid dynamic and structural correlations, the notable achievements of this work are the definition of best pressure static probes positioning and the maximum clogging level that a strainer can withstand before collapse. Furthermore, some guidelines are given in order to prevent pipeline resonance and acoustic fatigue caused by the interaction between strainer turbulence and compressor inlet flow.
Transfer matrix method applied to the parallel assembly of sound absorbing materials
Authors: Verdière Kévin , Panneton Raymond , Elkoun Saïd , Dupont Thomas , Leclaire Philippe
Published: December 2013

The transfer matrix method (TMM) is used conventionally to predict the acoustic properties of laterally infinite homogeneous layers assembled in series to form a multilayer. In this work, a parallel assembly process of transfer matrices is used to model heterogeneous materials such as patchworks, acoustic mosaics, or a collection of acoustic elements in parallel. In this method, it is assumed that each parallel element can be modeled by a 2 × 2 transfer matrix, and no diffusion exists between elements. The resulting transfer matrix of the parallel assembly is also a 2 × 2 matrix that can be assembled in series with the classical TMM. The method is validated by comparison with finite element (FE) simulations and acoustical tube measurements on different parallel/series configurations at normal and oblique incidence. The comparisons are in terms of sound absorption coefficient and transmission loss on experimental and simulated data and published data, notably published data on a parallel array of resonators. From these comparisons, the limitations of the method are discussed. Finally, applications to three-dimensional geometries are studied, where the geometries are discretized as in a FE concept. Compared to FE simulations, the extended TMM yields similar results with a trivial computation time.
Articulatory limit and extreme segmental reduction in Taiwan Mandarin
Authors: Cheng Chierh , Xu Yi
Published: December 2013

The present study investigated whether extreme phonetic reduction could result from acute time pressure, i.e., when a segment is given less articulation time than its minimum duration, as defined by Klatt [(1973). J. Acoust. Soc. Am. 54, 1102–1104]. Taiwan Mandarin was examined for its known high frequency of extreme reduction. Native speakers produced sentences containing nonsense disyllabic words with varying phonetic structures at different speech rates. High frequency words from spontaneous speech corpora were also examined for severe reduction. Results show that extreme reduction occurs frequently in nonsense words whenever local speech rate is roughly doubled from normal speech rate. The mean duration at which extreme reduction begins occurring is consistent with previously reported minimum segmental duration, maximum repetition rate and the rate of fast speech at which intelligibility is significantly reduced. Further examination of formant peak velocities as a function of formant displacement from both laboratory and corpus data shows that articulatory strength is not decreased during reduction. It is concluded that extreme reduction is not a feature unique only to high frequency words or casual speech, but a severe form of undershoot that occurs whenever time pressure is too great to allow the minimum execution of the required articulatory movement.
Clinical and Bacteriological Efficacy of Rifampin-Streptomycin Combination for Two Weeks followed by Rifampin and Clarithromycin for Six Weeks for Treatment of Mycobacterium ulcerans Disease
Authors: Phillips Richard O. , Sarfo Fred S. , Abass Mohammed K. , Abotsi Justice , Wilson Tuah , Forson Mark , Amoako Yaw A. , Thompson William , Asiedu Kingsley , Wansbrough-Jones Mark
Published: December 2013

Buruli ulcer, an ulcerating skin disease caused by
Mycobacterium ulcerans
infection, is common in tropical areas of western Africa. We determined the clinical and microbiological responses to administration of rifampin and streptomycin for 2 weeks followed by administration of rifampin and clarithromycin for 6 weeks in 43 patients with small laboratory-confirmed Buruli lesions and monitored for recurrence-free healing. Bacterial load in tissue samples before and after treatment for 6 and 12 weeks was monitored by semiquantitative culture. The success rate was 93%, and there was no recurrence after a 12-month follow-up. Eight percent had a positive culture 4 weeks after antibiotic treatment, but their lesions went on to heal. The findings indicate that rifampin and clarithromycin can replace rifampin and streptomycin for the continuation phase after rifampin and streptomycin administration for 2 weeks without any apparent loss of efficacy.
Traumatic orbital CSF leak
Authors: Borumandi Farzad
Published: December 2013

Compared to the cerebrospinalfluid (CSF) leak through the nose and ear, the orbital CSF leak is a rare and underreported condition following head trauma. We present the case of a 49-year-old woman with oedematous eyelid swelling and ecchymosis after a seemingly trivial fall onto the right orbit. Apart from the above, she was clinically unremarkable. The CT scan revealed a minimally displaced fracture of the orbital roof with no emphysema or intracranial bleeding. The fractured orbital roof in combination with the oedematous eyelid swelling raised the suspicion for orbital CSF leak. The MRI of the neurocranium demonstrated a small-sized CSF fistula extending from the anterior cranial fossa to the right orbit. The patient was treated conservatively and the lid swelling resolved completely after 5 days. Although rare, orbital CSF leak needs to be included in the differential diagnosis of periorbital swelling following orbital trauma.
Black spruce growth response to varying levels of biomass harvest intensity across a range of soil types: 15-year results
Authors: Morris Dave M. , Kwiaton Martin M. , Duckert Dan R.
Published: December 2013

With a growing interest in the diversification (e.g., bioenergy, biochemicals) of the forest industry beyond the traditional product streams, concerns that higher harvest utilization levels may compromise site productivity have been heightened. This study reports on 15-year tree growth responses to varying levels of biomass removals conducted on four soil types: loamy tills, outwash sands, wet mineral, and peatlands. Experimental harvest treatments included stem-only, full-tree, full-tree chipping (a full-tree harvest with the roadside material chipped and returned to the site), and full-tree + bladed (a full-tree harvest followed by forest floor removal). Results indicated no significant effect on height growth on the loamy tills, a significant decline for the blading treatment on the sandy soils, and an increase when the blading treatment was applied to the peatland sites. At the stand level, better planted seedling survival and higher recruitment of naturals on the more extreme removal treatment (forest floor removal on sandy sites) tended to nullify any negative impacts identified in the individual-tree growth measurements. The more than doubling of the slash loading on the stem-only treatment plots compared with the full-tree plots did not result in differences in tree productivity levels between these two operational treatments. The stands, however, were just approaching crown closure by year 15, suggesting that ongoing monitoring will be required to confirm that the growth trajectories for the various harvest treatment – soil type combinations can be maintained.
Speciation Studies of Diorganotin(IV) Complexes with 3,3‐Bis(1‐methylimidazol‐2‐yl)propionate—Displacement Reaction by DNA Constituents
Authors: Shoukry Mohamed M. , Hassan Safaa S.
Published: December 2013

The interaction of 3,3‐bis(1‐methylimidazol‐2‐yl)propionate (BIMP) with dimethyltin(IV) dichloride (DMT), dibutyltin(IV) dichloride (DBT), and diphenyltin(IV) dichloride (DPT) is investigated at 25°C and 0.1 M ionic strength in water for dimethyltin(IV), and in a 50% dioxane‐water mixture for dibutyltin(IV) and diphenyltin(IV). The stepwise formation constants of the 1 : 1 and 1 : 2 complexes formed in solution are calculated from potentiometric measurements using the nonlinear least‐square program MINIQUAD‐75. The concentration distribution of the various complex species is evaluated as a function of pH. Displacement reactions of the coordinated 3,3‐bis(1‐methylimidazol‐2‐yl)propionate by inosine and inosine‐5′‐monophosphate are investigated from calculations based upon equilibrium properties.
Pressure Losses across Multiple Fittings in Ventilation Ducts
Authors: Ai Z. T. , Mak C. M.
Published: December 2013

The accurate prediction of pressure losses across in‐duct fittings is of significance in relation to the accurate sizing and good energy efficiency of air‐delivery systems. Current design guides provide design methods and data for the prediction of pressure losses only for a single and isolated fitting. This study presents an investigation of pressure losses across multiple interactive in‐duct fittings in a ventilation duct. A laboratory measurement of pressure losses across one fitting and multiple fittings in a ventilation duct is carried out. The pressure loss across multiple interactive fittings is lower than that across multiple similar individual fittings, while the percentage decrease is dependent on the configuration and combination of the fittings. This implies that the pressure loss across multiple closely mounted fittings calculated by summing the pressure losses across individual fittings, as provided in the ASHRAE handbook and the CIBSE guide, is overpredicted. The numerical prediction of the pressure losses across multiple fittings using the large‐eddy simulation (LES) model shows good agreement with the measured data, suggesting that this model is a useful tool in ductwork design and can help to save experimental resources and improve experimental accuracy and reliability.
Cemented versus Uncemented Oxford Unicompartmental Knee Arthroplasty: Is There a Difference?
Authors: Akan Burak , Karaguven Dogac , Guclu Berk , Yildirim Tugrul , Kaya Alper , Armangil Mehmet , Cetin Ilker
Published: December 2013

Purpose. The use of uncemented unicompartmental knee prostheses has recently increased. However, few studies on the outcomes of uncemented unicompartmental knee prostheses have been performed. The purpose of this study was to compare the outcomes of cemented and uncemented Oxford unicompartmental knee arthroplasty.Materials and Methods. This retrospective observational study evaluated the clinical and radiological outcomes of 263 medial Oxford unicompartmental prostheses (141 cemented, 122 uncemented) implanted in 235 patients. The mean follow-up was 42 months in the cemented group and 30 months in the uncemented group.Results. At the last follow-up, there were no significant differences in the clinical results or survival rates between the two groups. However, the operation time in the uncemented unicompartmental knee arthroplasty group was shorter than that in the cemented unicompartmental knee arthroplasty group. In addition, the cost of uncemented arthroplasty was greater.Conclusion. Despite the successful midterm results in the uncemented unicompartmental knee arthroplasty group, a longer follow-up period is required to determine the best fixation mode.
Fetal Limb Ischaemia in Twin-to-Twin Transfusion Syndrome
Authors: Kilby Mark , Pounds Rachel , Mannix Paul
Published: December 2013

Objective. To describe the rare association between prenatal vascular limb occlusion and twin-to-twin transfusion syndrome.The Case. A woman with severe twin-to-twin transfusion syndrome was treated with fetoscopic laser ablation at 19-week gestation. At 27 weeks, the twins were delivered by an emergency caesarean section. The right arm of twin 1, the recipient twin, was noted to be “ischaemic” and was later amputated.Conclusion. This case is unusual in that it affected the upper limb and there was no evidence of polycythaemia, which is a suggested pathological mechanism. It was initially thought that the limb damage was due to the laser ablation, but after discussion with the fetal medicine team vascular limb occlusion in association with twin-to-twin transfusion syndrome was considered. Limb ischaemia is a serious complication of twin-to-twin transfusion syndrome and is unrelated to any form of fetal therapy.Implications. Neonatologists and paediatricians need to be aware of this association as it has medicolegal implications and parents should be counselled as to the possible, albeit rare, occurrence, especially when twin-to-twin transfusion syndrome is of advanced stage at presentation.
APOA2 Polymorphism in Relation to Obesity and Lipid Metabolism
Authors: Zaki Moushira Erfan , Amr Khalda Sayed , Abdel-Hamid Mohamed
Published: December 2013

Objectives. This study aims to analysis the relationship between c.-492T>C polymorphism in APOA2 gene and the risk for obesity in a sample of Egyptian adolescents and investigates its effect on body fat distribution and lipid metabolism. Material and Methods. A descriptive, cross-sectional study was conducted on 303 adolescents. They were 196 obese and 107 nonobese, aged 16–19 years old. Variables examined included body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR), systolic and diastolic blood pressure (BP), body fat percentage (BF%), abdominal visceral fat layer, and dietary intake. Abdominal visceral fat thickness was determined by ultrasonography. The polymorphism in the APOA2 c.-492T>C was analyzed by PCR amplification. Results. Genotype frequencies were in Hardy-Weinberg equilibrium. The frequency of the mutant C allele was significantly higher in obese cases compared to nonobese. After multivariate adjustment, waist, BF% and visceral adipose layer, food consumption, and HDL-C were significantly higher in homozygous allele CC carriers than TT+TC carriers. Conclusions. Homozygous individuals for the C allele had higher obesity risk than carriers of the T allele and had elevated levels of visceral adipose tissue and serum HDL-C. Moreover, the study shows association between the APOA2 c.-492T>C polymorphism and food consumption.
Numerical Solution of Some Types of Fractional Optimal Control Problems
Authors: Sweilam Nasser Hassan , Al-Ajami Tamer Mostafa , Hoppe Ronald H. W.
Published: December 2013

We present two different approaches for the numerical solution of fractional optimal control problems (FOCPs) based on a spectral method using Chebyshev polynomials. The fractional derivative is described in the Caputo sense. The first approach follows the paradigm “optimize first, then discretize” and relies on the approximation of the necessary optimality conditions in terms of the associated Hamiltonian. In the second approach, the state equation is discretized first using the Clenshaw and Curtis scheme for the numerical integration of nonsingular functions followed by the Rayleigh‐Ritz method to evaluate both the state and control variables. Two illustrative examples are included to demonstrate the validity and applicability of the suggested approaches.
Random Access Control for M2M in LTE System
Authors: Chen Zhide , Zeng Yali
Published: December 2013

With the implementation of 4G mobile networks, the number of M2M users will be much large in a cell. When massive M2M users try to randomly access simultaneously, this will impose a great influence on H2H communication. Without effective control, these M2M users will lead to a system breakdown. In this paper, we put forward a model, which allows low delay tolerance of users to have a higher priority for random access, when contending with high delay tolerance of users for limited random access resources. In this model, by controlling access rates of different delay tolerance of users, the random access success probability will be improved efficiently. In the meantime, it will achieve the highest success probability and optimize the system performance by setting optimal access rates for different delay tolerance of users. This will be a practical guide to M2M communication in LTE system.
Achieving Motor Development Milestones at the Age of Three Months May Determine, but Does Not Guarantee, Proper Further Development
Authors: Gajewska Ewa , Sobieska Magdalena , Kaczmarek Elżbieta , Suwalska Aleksandra , Steinborn Barbara
Published: December 2013

Proper motor performance at 3rd month is necessary for further motor development. The paper aims to demonstrate the reliability, sensitivity, and predictive value of an original motor performance assessment tool in comparison with the neurological assessment at 3, 6, and 9 months. Children (n = 123), born at term without pre‐ or perinatal complications, born at term with pre‐ or perinatal complications, or born preterm, were assessed at the age of 3, 6, and 9 months, by a neurologist and a physiotherapist. The physiotherapist evaluated 15 qualitative features typical for the age of 3 months in the prone and supine positions. The final neurological assessment determined the degree of developmental disorder. Neurological and global physiotherapeutic assessments showed a statistically significant correlation. Qualitative assessment results were very good in healthy children and decreased with worsening neurological diagnoses. Children diagnosed with cerebral palsy did not show proper qualitative features of 3 months when analyzed at 3, 6, and 9 months. Children with delayed motor development revealed minor qualitative performance impairments as early as 3 months but improved with age. Qualitative assessment at 3 months not only facilitates diagnosis of major developmental disorders but is also a good predictor of delayed motor development in children.
A Novel Artificial Bee Colony Approach of Live Virtual Machine Migration Policy Using Bayes Theorem
Authors: Xu Gaochao , Ding Yan , Zhao Jia , Hu Liang , Fu Xiaodong
Published: December 2013

Green cloud data center has become a research hotspot of virtualized cloud computing architecture. Since live virtual machine (VM) migration technology is widely used and studied in cloud computing, we have focused on the VM placement selection of live migration for power saving. We present a novel heuristic approach which is called PS‐ABC. Its algorithm includes two parts. One is that it combines the artificial bee colony (ABC) idea with the uniform random initialization idea, the binary search idea, and Boltzmann selection policy to achieve an improved ABC‐based approach with better global exploration’s ability and local exploitation’s ability. The other one is that it uses the Bayes theorem to further optimize the improved ABC‐based process to faster get the final optimal solution. As a result, the whole approach achieves a longer‐term efficient optimization for power saving. The experimental results demonstrate that PS‐ABC evidently reduces the total incremental power consumption and better protects the performance of VM running and migrating compared with the existing research. It makes the result of live VM migration more high‐effective and meaningful.
Improved Performance of an Epoxy Matrix as a Result of Combining Graphene Oxide and Reduced Graphene
Authors: Ramos-Galicia L. , Mendez L. N. , Martínez-Hernández Ana Laura , Espindola-Gonzalez A. , Galindo-Esquivel I. R. , Fuentes-Ramirez R. , Velasco-Santos C.
Published: December 2013

We present an easy and effective way to improve the mechanical properties of an epoxy matrix by reinforcing it with a combination of graphene oxide (GO) and reduced graphene oxide (RGO). These nanocomposites were prepared with different load of nanofillers: 0.1, 0.4, 0.7, 1.0 wt% and a neat epoxy. Ratios of graphene oxide and reduced graphene (GO : RGO) employed were: 0 : 1, 0.25 : 0.75, 0.5 : 0.5, 0.75 : 0.25, and 1 : 0. Results show that with only 0.4 wt% and a ratio 0.2 : 0.75 of GO : RGO, tensile strength and tensile toughness are 52% and 152% higher than neat epoxy while modulus of elasticity was improved~20%. The obtained results suggest that it is possible achieve advantageous properties by combining graphene in oxidized and reduced conditions as it shows a synergic effect by the presence of both nanofillers.
Harmonic Balance Method for Chaotic Dynamics in Fractional-Order Rössler Toroidal System
Authors: Zhu Huijian
Published: December 2013

This paper deals with the problem of determining the conditions under which fractional order Rössler toroidal system can give rise to chaotic behavior. Based on the harmonic balance method, four detailed steps are presented for predicting the existence and the location of chaotic motions. Numerical simulations are performed to verify the theoretical analysis by straightforward computations.
On the Largest Disc Mapped by Sum of Convex and Starlike Functions
Authors: Ali Rosihan M. , Jain Naveen Kumar , Ravichandran V.
Published: December 2013

For a normalized analytic functionfdefined on the unit disc𝔻, letϕ(f,f′,f′′;z)be a function of positive real part in𝔻,ψ(f,f′,f′′;z)need not have that property in𝔻, andχ=ϕ+ψ. For certain choices ofϕandψ, a sharp radius constantρis determined,0<ρ<1, so thatχ(ρz)/ρmaps𝔻onto a specified region in the right half-plane.
Preparation and Performance of cis‐Polybutadiene Rubber Composite Materials Reinforced by Organic Modified Palygorskite Nanomaterials
Authors: Wang Fei , Feng Lei , Tang Qingguo , Liu Haifeng , Liu Huimin
Published: December 2013

The hydrophilic character of palygorskite has been modified by grafting organic group and controlling surface energy for improving compatibility of palygorskite in rubber matrix using palygorskite as cis‐polybutadiene rubber fillers. The effects of coupling modification on the performance of cis‐polybutadiene rubber materials filled with palygorskite were investigated, and the influence of coupling agent dosage on their mechanical properties was also studied. The results indicated that the mechanical performance of cis‐polybutadiene rubber materials reinforced by modified palygorskite could be improved significantly, and the tensile strength and tearing strength increased by 122.5% and 107.6% at the optimal dosage (15%) of coupling agent 3‐mercaptopropyl trimethoxysilane. Moreover, the reinforcement mechanism of rubber composite materials as prepared was also analyzed.
A Unique Case of Late Complication of Rectum Mesh Erosion after Laparoscopic Sacrocolpopexy
Authors: Balzarro M. , Rubilotta E. , Sarti A. , Curti P. , Artibani W.
Published: December 2013

Sacrocolpopexy, a surgical technique with a low morbidity rate, is a valid procedure for repairing vaginal vault prolapse. To our knowledge, only 1 case of rectum erosion after open sacrocolpopexy has been reported in the literature, and there is no record of any such incident after laparoscopic sacrocolpopexy. We report the first case of mesh erosion involving the rectum instead of the vagina assessed 8 years after laparoscopic sacrocolpopexy.
Detection of Herpes Viruses by Multiplex and Real-Time Polymerase Chain Reaction in Bronchoalveolar Lavage Fluid of Patients with Acute Lung Injury or Acute Respiratory Distress Syndrome
Authors: Tachikawa Ryo , Tomii Keisuke , Seo Ryutaro , Nagata Kazuma , Otsuka Kyoko , Nakagawa Atsushi , Otsuka Kojiro , Hashimoto Hisako , Watanabe Ken , Shimizu Norio
Published: December 2013

Background: Human herpes viruses (HHVs) are important pathogens in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Rapid and efficient diagnostic tools are needed to detect HHVs in the lung in ALI/ARDS patients. Objectives: This study aimed to evaluate the usefulness of multiplex and real-time polymerase chain reaction (PCR) analysis of bronchoalveolar lavage fluid (BALF) for detecting HHV reactivation in ALI/ARDS patients. Methods: Between August 2008 and July 2012, eighty-seven BALF samples were obtained from ALI/ARDS patients with unknown etiology and analyzed for HHVs. The types of HHVs in the BALF samples were determined using qualitative multiplex PCR followed by quantitative real-time PCR. Results: Multiplex PCR identified herpes simplex virus type 1 (HSV-1) (n = 11), Epstein-Barr virus (EBV) (n = 16), cytomegalovirus (CMV) (n = 21), HHV type 6 (HHV-6) (n = 2), and HHV-7 (n = 1) genomic DNA in 35 (40%) of the BALF samples, including 14 (16%) samples containing 2 or 3 HHV types. CMV and EBV reactivation was rare in immunocompetent patients, whereas reactivation of HSV-1 was predominantly observed in intubated patients regardless of their immune status. Overall, HHVs were almost exclusively found in patients with immunosuppression or endotracheal intubation. Real-time PCR detected 0.95-1.59 × 106 copies of viral DNA/μg human genome DNA, and HSV-1 (n = 4), CMV (n = 9), and HHV-6 (n = 1) were identified as potentially pathogenic agents. Conclusions: The implementation of multiplex and real-time PCR of BALF was feasible in ALI/ARDS patients, which allowed efficient detection and quantification of HHV DNA.
Human NELL1 Protein Augments Constructive Tissue Remodeling with Biologic Scaffolds
Authors: Turner Neill J. , Londono Ricardo , Dearth Christopher L. , Culiat Cymbeline T. , Badylak Stephen F.
Published: December 2013

Biologic scaffolds composed of extracellular matrix (ECM) derived from decellularized tissues effectively reprogram key stages of the mammalian response to injury, altering the wound microenvironment from one that promotes scar tissue formation to one that stimulates constructive and functional tissue remodeling. In contrast, engineered scaffolds, composed of purified ECM components such as collagen, lack the complex ultrastructure and composition of intact ECM and may promote wound healing but lack factors that facilitate constructive and functional tissue remodeling. The objective of the present study was to test the hypothesis that addition of NELL1, a signaling protein that controls cell growth and differentiation, enhances the constructive tissue remodeling of a purified collagen scaffold. An abdominal wall defect model in the rat of 1.5-cm2 partial thickness was used to compare the constructive remodeling of a bovine type I collagen scaffold to a biologic scaffold derived from small intestinal submucosa (SIS)-ECM with and without augmentation with 17 μg NELL1 protein. Samples were evaluated histologically at 14 days and 4 months. The contractile response of the defect site was also evaluated at 4 months. Addition of NELL1 protein improved the constructive remodeling of collagen scaffolds but not SIS-ECM scaffolds. Results showed an increase in the contractile force of the remodeled skeletal muscle and a fast:slow muscle composition similar to native tissue in the collagen-treated group. The already robust remodeling response to SIS-ECM was not enhanced by NELL1 at the dose tested. These findings suggest that NELL1 protein does contribute to the enhanced constructive remodeling of skeletal muscle.
Dopamine Ramps Are a Consequence of Reward Prediction Errors
Authors: Gershman Samuel J.
Published: December 2013

Temporal difference learning models of dopamine assert that phasic levels of dopamine encode a reward prediction error. However, this hypothesis has been challenged by recent observations of gradually ramping stratal dopamine levels as a goal is approached. This note describes conditions under which temporal difference learning models predict dopamine ramping. The key idea is representational: a quadratic transformation of proximity to the goal implies approximately linear ramping, as observed experimentally.
A Fire-Risk-Breakdown System for Electrical Power Lines in the North of Brazil
Authors: França Gutemberg Borges , Oliveira Antonio Nascimento de , Paiva Célia Maria , Peres Leonardo de Faria , Silva Michael Bezerra da , Oliveira Luciana Maria Temponi de
Published: December 2013

Anthropogenic or spontaneous fires (hotspots) are the main causes of unexpected breakdowns of electrical power lines in the northern region of Brazil. This research has tested, adapted, and implemented a preoperational system aiming to prevent electrical breakdowns for 382 km of electrical transmission lines in the state of Maranhão. The breakdown electrical fire risk is based on a combination of three variables: 1) the fire risk index, 2) the remotely sensed hotspot presence in the vicinity of electrical power lines, and 3) the vegetation stage. These variables are converted into Boolean variables, and their combination will classify the electrical fire risk as extreme, high, medium, low, or null. In regard to the system input variables, the fire risk index carries the highest representativeness in composition value of the breakdown electrical fire risk. Therefore, the results of two fire risk indices, calculated on the basis of the (a) Monte Alegre and (b) Angstrom methods, are presented and discussed. The validation of the fire risk indices is based on six categorical statistics (with the obtained final values also indicated in parentheses for the Monte Alegre and Angstrom methods, respectively): accuracy (0.91, 0.92), bias (1.05, 1.06), probability of detection (0.98, 0.99), false-alarm ratio (0.07, 0.07), probability of false detection (0.90, 0.80), and threat score (0.91, 0.92). The system presented here may be used as a tool within the electrical sector to prevent and respond to sudden electrical power line breakdowns.
Influence of Surface Observations in Mesoscale Data Assimilation Using an Ensemble Kalman Filter
Authors: Ha So-Young , Snyder Chris
Published: December 2013

The assimilation of surface observations using an ensemble Kalman filter (EnKF) approach was successfully performed in the Advanced Research version of the Weather Research and Forecasting Model (WRF) coupled with the Data Assimilation Research Testbed (DART) system. The mesoscale cycling experiment for the continuous ensemble data assimilation was verified against independent surface mesonet observations and demonstrated the positive impact on short-range forecasts over the contiguous U.S. (CONUS) domain throughout the month-long period of June 2008. The EnKF assimilation of surface observations was found useful for systematically improving the simulation of the depth and the structure of the planetary boundary layer (PBL) and the reduction of surface bias errors. These benefits were extended above PBL and resulted in a better precipitation forecast for up to 12 h. With the careful specification of observation errors, not only the reliability of the ensemble system but also the quality of the following forecast was improved, especially in moisture. In this retrospective case study of a squall line, assimilation of surface observations produced analysis increments consistent with the structure and dynamics of the boundary layer. As a result, it enhanced the horizontal gradient of temperature and moisture across the frontal system to provide a favorable condition for the convective initiation and the following heavy rainfall prediction in the Oklahoma Panhandle. Even with the assimilation of upper-level observations, the analysis without the assimilation of surface observations simulated a surface cold front that was much weaker and slower than observed.
Book Review: Medieval Indian Mindscapes: Space, Time, Society, Man
Authors: Mukhia Harbans
Published: December 2013

Eugenia Vanina, Medieval Indian Mindscapes: Space, Time, Society, Man, Primus Books, New Delhi, 2012, pp. 336, ₹995. ISBN: 978-93-80607-19-1.