bluuebunny/crossref_metadata_2025 huggingface dataset:
Wear Locations in Stainless Steel Pipe Fittings From the Turbulent Flow of a Liquid-Solid Slurry
Authors: Duignan Mark R. , Reigel Marissa M. , Imrich Kenneth J. , Restivo Michael L. , Fowley Mark D.
Published: March 2016

The United States Department of Energy (DOE) is building a Waste Treatment Plant (WTP) at the DOE Hanford Site in the state of Washington to process stored radioactive wastes for long-term storage and disposal. The Savannah River National Laboratory (SRNL) is helping resolve technical concerns with the WTP, which are related to piping erosion/corrosion (wear). SRNL is assisting in the design of a flow loop to obtain long term wear rates that will use prototypic simulant chemistry, operating conditions, and materials. The challenge is to accurately measure slurry wear to a pipe wall thickness tolerance of 47 microns/year anywhere in the test flow loop in a timely manner. A first step in such a test is to secure knowledge of high wear locations so that highly sensitive measurement techniques can be incorporated and properly located. Literature exists to help locate such wear locations in pipe and pipe fittings but most of the information deals with slurry flows that have significantly different velocities, different flows steams, e.g., steam, gas-liquid-solids, or made from different materials. To better estimate these high wear rate locations under the WTP conditions a separate pre-test flow loop was constructed and operated. This loop is referred to as the paint loop because it was internally coated with paint, which wears faster than the steel pipe, when a solids-laden slurry is circulated. The test flow conditions were a slurry velocity of 4 m/s in a 0.0762 -m (3-inch) Schedule 40 pipe system, resulting in Reynolds number just above 3 × 105, i.e., turbulent flow at a temperature of 25°C. The slurry was a mixture of water and sand, d50 ∼ 199 microns. This paper describes the test paint loop, its operation, and indicates the high slurry wear locations, as well as a comparison of those locations to existing literature sources.
A Study on the Effect of Mean Cyclic Temperature on the Thermal Fatigue Reliability of SAC Solder Joints Using Digital Image Correlation
Authors: Lall Pradeep , Mirza Kazi
Published: March 2016

Electronics in high reliability applications may be subjected to cyclic thermo-mechanical loads after being deployed for extended periods of time in harsh environment. Cyclic thermal excursion may result in solder joint fatigue leading to failure. Previous researchers have shown that exposure to high temperature for extended periods of time results in evolution of the mechanical properties of SnAgCu alloys. Deployment of leadfree electronics in harsh environment applications may result in exposure to a multitude of thermal cycles. The effect of cyclic thermal range and thermal aging on the thermal fatigue reliability has been widely documented; however the effect of the mean temperature on the thermal fatigue reliability and the strain evolution of during cyclic exposure has not been studied. In this paper, an experimental investigation has been undertaken using digital image correlation to quantify the evolution in the strain state under different mean temperatures and cyclic thermal intervals. Three different test vehicles including BGA144, BGA256 and BGA324 were used in this study under three different test conditions −50°C to +50°C, 0°C to 100°C, 50°C to 150°C. A framework to evaluate the effect of mean temperature of thermal cycle has been developed.
Fabrication of Plastic Micro-Channels for Microfluidics Solvent Extraction
Authors: Dankovic Tatjana , Hatch Gareth , Feinerman Alan
Published: March 2016

In this work plastic micro channel systems were investigated as a potential device for micro solvent extraction of rare earth elements. The proposed microfluidic structures are made by laser welding of three layers of inexpensive thermoplastic films which form separate paths (top and bottom channels) for each of the immiscible fluids. The middle layer is perforated in order to provide contact between two fluids and to enable the extraction process. Experiments were performed to show that two different immiscible fluids (water and 1-octanol) can flow through the fabricated device and exit at separate outlets without mixing even when those fluids get into close contact within the main channel. Experimental results for single devices show that immiscible fluids can be brought into intimate contact and then separated with compliant polymeric microfluidic devices. The transfer of a compound from one immiscible fluid to the other was verified by dye exchange between the immiscible fluids. The same fabrication method is a promising technique for fabrication of massively parallel systems with larger throughput.
Vehicle and Occupant Response in Low-Speed Go-Kart Crash Tests
Authors: Kloppenborg Nick , Amenson Tara , Wernik Jacob , Wiechel John
Published: March 2016

Go-karts are a common amusement park feature enjoyed by people of all ages. While intended for racing, contact between go-karts does occur. To investigate and quantify the accelerations and forces which result from contact, 44 low-speed impacts were conducted between a stationary (target) and a moving (bullet) go-kart. The occupant of the bullet go-kart was one of two human volunteers. The occupant of the target go-kart was a Hybrid III 50th percentile male anthropomorphic test device (ATD). Impact configurations consisted of rear-end impacts, frontal impacts, side impacts, and oblique impacts. Results demonstrated high repeatability for the vehicle performance and occupant response. Go-kart accelerations and velocity changes increased with increased impact speed. Impact duration and restitution generally decreased with increased impact speed. All ATD acceleration, force, and moment values increased with increased impact speed. Common injury metrics such as the Head Injury Criterion (HIC), Nij, and Nkm were calculated and were found to be fairly low. These results indicate that the potential for serious injury is low during low-speed go-kart impacts.
Influence of Gas Diluents on the Temperature of a Laminar Coflowing Jet Diffusion Flame in a Honeycomb Gaseous Burner
Authors: Attia Amr , Emara Ahmed
Published: March 2016

A series of experiments were performed on a flat honeycomb burner with air coflow to ensure laminar flow in order to study the effect of Acetylene/Argon mixture to the natural gas (NG) on the temperature distribution and flame structure. The burner assembly could be traversed in the horizontal and vertical direction controlled by using a field point system to scan the flame radially and axially. The flow rate of fuel, diluents and air was measured using differential pressure flow meters. The whole supply lines were calibrated. Methane gas, air and Acetylene/Argon mixture were injected through mixing pipes controlled with solenoid valves handled with a LabVIEW program. The combustion flame was in room atmospheric conditions with room disturbances controlled to treat such flames as free jet diffusion flames. The laminar flame axial and radial temperature profile was measured using a shielded-aspirated platinum/ Platinum-13% Rhodium thermocouple (type R). Flame images were taken using Canon EOS camera with CMOS sensor, up to 3.7 fps. The fuel used was NG with flow rate from 180 up to 520 ml/min. Ar flow rate up to 350 ml/min and C2H2 up to 100 ml/min with a constant coflow air of 3 l/min. The choice of the different Investigated cases was based on flame stability. The results obtained indicate the following:

– In case of using air, NG and Ar, the fuel rich zone tends to vanish and in case of injecting Ar and acetylene mixture in addition of NG and air the front zone tends to vanish and the flame became mainly diffusion.

– Maximum temperature was at the flame tip in all cases. Increasing Ar percentage up to 50% decreases tip temperature to nearly 870°C compared to the typical case (about 1000 °C); increasing acetylene content over 15% resulted in dense soot formation.
Effects of Spray-Swirl Interactions on Heat Losses in a Light Duty Diesel Engine
Authors: Dahlström Jessica , Andersson Öivind , Tunér Martin , Persson Håkan
Published: March 2016

Heat loss is one of the greatest energy losses in engines. More than half of the heat is lost to cooling media and exhaust losses, and they thus dominate the internal combustion engine energy balance. Complex processes affect heat loss to the cylinder walls, including gas motion, spray-wall interaction and turbulence levels. The aim of this work was to study and improve the heat transfer characteristics of conventional diesel combustion. Speed, load, injection pressure, swirl level, EGR rate and air/fuel ratio (λ) were varied in a multi-cylinder engine. Temperature measurements in the engine cooling media were used to set up the engine energy balance and find out how much heat was lost to cooling media in different parts of the engine. Based on these calculations and heat release analysis, conclusions could be drawn regarding how heat losses in different parts of the engine were affected by changes in these parameters. Load was found to be more influential than speed, swirl did not have any effect on heat transfer, and EGR and λ both increased cooling water losses while piston losses were reduced.
An Intake System Optimization of a Heavy Duty DI Diesel Engine Using CFD Analysis
Authors: Emara Kareem , Emara Ahmed , Abdel Razek Elsayed
Published: March 2016

As the intake system design is significant for the optimal performance of internal combustion engines, this work aims to optimize the geometry of an intake system in a direct injection (DI) diesel engine. The study concerns the geometry effects of three different intake manifolds mounted consecutively on a fully instrumented, six cylinders, in line, water cooled, 19.1 liters displacement, DI heavy duty diesel engine. A 3D numerical simulation of the turbulent flow through these manifolds is applied. The model is based on solving Navier-Stokes and energy equations in conjunction with the standard K-ε turbulence model and hypothetical boundary conditions using ANSYS- CFX 15. Numerical results of this simulation are presented in the form of flow field velocity as well as pressure field. Optimal design of the intake system is performed and the modeling made it possible to provide a fine knowledge of in-flow structures, in order to examine the adequate manifold. Engine performance characteristics such as brake torque, brake power, thermal efficiency and specific fuel consumption are also carried out to evaluate the effects of the variation in the intake manifold geometry and to validate the optimal design. Simulation and experimental results confirmed the effectiveness of the optimized manifold geometry on the engine performances.
Simulation of Wind Turbine Flow Using the Actuator Line Method in NEK5000
Authors: O’Dea Murphy Leo , Guessous Laila
Published: March 2016

Wind turbine wake models are used to estimate the velocity profile and magnitude downstream of wind towers in large wind farms. Current models are based on simple geometric and empirical factors, which typically overestimate individual turbine output. Recent research has focused on using improved models of turbine rotors, combined with computational fluid dynamics (CFD) programs to simulate turbine wake flow.

In this paper, we report on our efforts to simulate flow past wind turbines using a new adaptation of the actuator line method for turbine blade modeling. This method creates a geometric representation of each rotating turbine blade. Grid points in the CFD flow field are selected within the outline of the blades and near downstream planes, and the aerodynamic forces are calculated using traditional blade element equations. Blade forces are then input as body forces into the Navier Stokes equations in the host CFD program. This model is combined with the advanced parallel CFD code, NEK5000, which has been proven to provide high-resolution results with significantly reduced compute resources. Program subroutines are developed to generate the actuator line and blade geometry, and to calculate the blade lift and drag forces. Details of the actuator line setup and calculations, CFD flow simulation setup, and results from current development runs simulating a single turbine will be presented. Current results are consistent with published research. Lessons learned, and a roadmap to ongoing development are also discussed.
The Fatigue Life Prediction Methodology Based on the Unigrow Model
Authors: Bogdanov Sergey , Mikheevskiy Semyon , Glinka Grzegorz
Published: March 2016

This paper is concerned with the problem of prediction of the total life of an engineering structure based on the fatigue crack growth model. The life of an engineering component is generally modeled as a combination of the time required for a crack to initiate and then the time required for crack to propagate till the final fracture. Unfortunately the crack initiation size is a vaguely defined parameter. In order to overcome this ambiguity it is proposed to model the total life of an engineering structure by using the UniGrow fatigue crack growth model with assumption of the intrinsic material parameter ρ* as an initial crack size. The method to overcome the small crack problem in fatigue crack modeling is presented as well. The proposed model was successfully used to predict fatigue lives of misaligned cruciform welded joints under a constant amplitude loading. Results from the analysis and experiment are in a good agreement.
Finite Element Modelling of a Modified Kolsky Bar Developed for High Strain Rate Testing of Elastomers
Authors: Chaudhry M. S. , Carrick R. , Czekanski A.
Published: March 2016

Elastomers are finding a wide variety of dynamic applications in aerospace, automobile and biomedical industries. The response of these complex material is based on the loading conditions and the strain rate at which the loading is applied. To suit the designer’s requirement, there is an ever increasing need to characterize this application specific, dynamic behavior under high strain rates. The Kolsky bar apparatus, also known as the Split Hopkinson Bar, is the most common apparatus used to test engineering materials at strain rates between 100/s and 10000/s. In this paper a modified Kolsky bar to characterize soft material is numerically modeled using Finite Element Method. The focus of the study is to numerically analyze the modifications made to a conventional Kolsky bar to specifically test nonlinear hyperelastic, soft materials. The challenge for testing low strength materials is the impedance mismatch between the bar and specimen interfaces, which results in a very weak distorted signal. One of the solution is to use a hollow transmission bar instead of solid one. With the use of FEM it can be numerically verified that using a hollow bar increases the amplitude of the transmitted signal up to several times. It is known that the rise time of the elastic wave can be increased by using a copper pulse shaper. Different dimensions of pulse shaper are modeled and the effect on the incident pulse is analyzed. The main aim of this study is to provide a detailed numerical analysis on the testing parameters, and to model one way wave propagation in Kolsky bar experiment for hyperelastic materials. The constitutive equations used to model the parts of the apparatus are also discussed.
Influences of Variable Mass Flowrate of Refrigerant Blend R125/R290 on Heat Pump Performance
Authors: Wang Fang , Fan Xiaowei , Guo Zhuangyu , Zhang Lu , Zheng Huiyan
Published: March 2016

The off-design experimental performances of heat pump system using R125/R290 (25/75, mass fraction) blend are investigated by varying the mass flowrate of refrigerant blend. The influences of variable mass flowrate upon system coefficient of performance (COP), discharge temperature, temperature glide (GT) and temperature profile in condenser are analyzed, the system performance comparisons between R125/R290 and substituted refrigerant R22 are carried out. The results show that when the blend mass flowrate increases, compressor power increases linearly, the COP linearly increases at first and then gradually decreases, and an optimum COP of 3.04 is obtained when mixture mass flowrate reaches 1.12 kg/min. The compressor discharge temperature is almost decreased linearly whereas specific mass heating capacity is increased firstly and then it has a drop. The temperature differences between refrigerant and water at the inlet and in the middle of the condenser is gradually increased while the one at the outlet is decreased gradually with a heat transfer pinch point kept in the middle of the heat exchanger. Compared with that of R22, the overall performance has proved that the new refrigerant blend could be a promising substitute for R22, which are of significance for the application of the new refrigerant blends used in heat pump system.
Research on the Override Phenomenon in Railway Collision Accidents
Authors: Zhou Hechao , Zhang Jimin , Zhang Jitong
Published: March 2016

In this paper, a joint simulat ion method based on nonlinear FEM and MBD is proposed. Firstly, the force-deformation character of single vehicle is analysed using nonlinear FEM software Dytran. Then, override simulations of two train units in frontal collision are carried out using multi-body dynamics. Simulation results indicate that the pitching motion of vehicles has great effect to the overriding phenomenon. It also depends on several factors, such as collision mass, pitching frequency, height of the center of mass above the rail level. Besides that, it is shown in this paper the overriding phenomenon is more sensitive to variations in pitching frequency and height of the center of mass, compared to the factor of collision mass.
Multi-Objective Optimization of Micro Pin-Fin Arrays for Cooling of High Heat Flux Electronics
Authors: Reddy Sohail R. , Dulikravich George S.
Published: March 2016

The thermal management capability of various candidates of micro-pin fin arrays is investigated. An integrated circuit having a footprint of 4 × 3 mm with micro-pin fin array having circular, airfoil and convex cross-section is considered. The three pin fin cross-sections along with the cooling schemes are optimized to handle a uniform heat flux of 500 W/cm2 applied to the top surface of the electronic chip. A fully three-dimensional, steady-state conjugate heat transfer analysis was performed on each cooling configuration and a constrained multi-objective optimization was carried out for each of the three micro-pin fin shapes to find pin fin designs configurations capable of cooling such high heat fluxes. The design variables were the geometric parameters defining each pin fin cross section, height of the chip and inlet speed of the coolant. The two simultaneous objectives were to minimize maximum temperature and pressure drop (pumping power), while keeping the maximum temperature below 85°C. A response surface was constructed for each objective function and was coupled with a genetic algorithm to arrive at a Pareto frontier of the best trade-off solutions. Stress-deformation analysis incorporating the hydrodynamic and thermal loads was performed on each of the three optimized configurations. The maximum displacement was found to be on the nano-level, and the Von-Mises stress for each configuration was found to be significantly below the yield strength of Silicon.
Experimental Study of the Spanwise Wake Compression of a Trapezoidal Pitching Panel
Authors: King Justin T. , Green Melissa A.
Published: March 2016

Aquatic animals can maneuver and propel themselves through a variety of means. Among these means, are the oscillation and undulation of the flukes and fins of different cetaceans and fishes. The motions of these species can be employed to develop thrust-producing, highly three-dimensional wakes. Recently, a great deal of interest in incorporating certain biological propulsion schemes into engineering designs has been generated. Experiments have shown that bio-inspired propulsors can develop large efficiencies, with some efficiencies being greater than those of a screw-propeller propulsion system.

In the current work, stereoscopic particle image velocimetry (PIV) was used to characterize the wake produced by a rigid, trapezoidal pitching panel. Prior work has shown that one of the dominant parameters governing wake structure is the Strouhal number. Detailed analysis in terms of Strouhal number is the focus of the current work, and the Strouhal number range tested was from 0.17 to 0.56.
Ultrasound viscoelasticity assessment using an adaptive torsional shear wave propagation method
Authors: Ouared Abderrahmane , Kazemirad Siavash , Montagnon Emmanuel , Cloutier Guy
Published: March 2016

Purpose:

Different approaches have been used in dynamic elastography to assess mechanical properties of biological tissues. Most techniques are based on a simple inversion based on the measurement of the shear wave speed to assess elasticity, whereas some recent strategies use more elaborated analytical or finite element method (FEM) models. In this study, a new method is proposed for the quantification of both shear storage and loss moduli of confined lesions, in the context of breast imaging, using adaptive torsional shear waves (ATSWs) generated remotely with radiation pressure.

Methods:

A FEM model was developed to solve the inverse wave propagation problem and obtain viscoelastic properties of interrogated media. The inverse problem was formulated and solved in the frequency domain and its robustness to noise and geometric constraints was evaluated. The proposed model was validated in vitro with two independent rheology methods on several homogeneous and heterogeneous breast tissue‐mimicking phantoms over a broad range of frequencies (up to 400 Hz).

Results:

Viscoelastic properties matched benchmark rheology methods with discrepancies of 8%–38% for the shear modulus G′ and 9%–67% for the loss modulus G″. The robustness study indicated good estimations of storage and loss moduli (maximum mean errors of 19% on G′ and 32% on G″) for signal‐to‐noise ratios between 19.5 and 8.5 dB. Larger errors were noticed in the case of biases in lesion dimension and position.

Conclusions:

The ATSW method revealed that it is possible to estimate the viscoelasticity of biological tissues with torsional shear waves when small biases in lesion geometry exist.
Evidence for a delay in diagnosis of Wilms’ tumour in the UK compared with Germany: implications for primary care for children
Authors: Pritchard-Jones Kathy , Graf Norbert , van Tinteren Harm , Craft Alan
Published: March 2016

The UK has a longstanding system of general practice which provides the vast majority of primary care, including that for children. It acts as a 'gatekeeper' to more specialist care. Parents may also use accident and emergency departments as their first point of medical contact for their children. Outcomes in the UK for many conditions in children appear to be worse than in comparable European countries where there is direct access to care by paediatricians. We have therefore looked at pathways to diagnosis and compared outcomes in the childhood kidney cancer, Wilms' tumour, which has been treated in the UK and Germany within the same clinical trial for over a decade. We find that Wilms' tumours are significantly larger in volume and have a more advanced tumour stage at diagnosis in the UK compared to Germany. There is a small (∼3%) difference in event free and overall survival between the two countries. Our data suggest that the system of primary care for children in the UK is less likely to result in the incidental finding of an abdominal mass in a child with no or vague symptoms. This may be a reason for the poorer outcome.
Oral ulcerations after placement of orthodontic braces and skin pustules after laser hair removal: novel inducers of pathergy reactions in new-onset Behçet's disease
Authors: van de Ree-Pellikaan Claire , Kiewiet-Kemper Rosalie M , Tchetverikov Ilja , Westerweel Peter E
Published: March 2016

A 25-year-old man was admitted to our hospital, with fever, severe ulceration of the oral and pharyngeal mucosa, and pustules on his skin. These pathergy-like lesions had emerged after placement of orthodontic braces and laser therapy for hair removal, respectively. The patient's clinical condition, together with his ethnic background, pointed to the diagnosis of Behçet's disease. Treatment with colchicine and prednisone resulted in rapid improvement of his symptoms. Pathergy reactions in response to placement of dental braces and laser hair removal are a rare first presentation of Behçet's disease.
Primary renal carcinoid tumour with lung metastasis misdiagnosed as renal cell carcinoma
Authors: Daboul Nour , Monga Dulabh , Bunker Mark
Published: March 2016

A 58-year-old man with a history of metastatic renal cell carcinoma (RCC) diagnosed 10 years prior, status post right nephrectomy, presented for evaluation of pulmonary nodules. A year after the nephrectomy, he had undergone cutaneous metastasectomy in the right flank area, and a further 2 years later he had had his second cutaneous metastasectomy in the right chest wall. Both cutaneous pathologies had, at the time, shown metastatic neoplasm with histological features compatible with those of the previous renal tumour. He was treated with sorafenib. 3 years later he developed asymptomatic pulmonary nodules, which gradually doubled in size over the next 2.5 years. He underwent bronchoscopy and left lower lobe biopsy. Pathology revealed a metastatic renal carcinoid/neuroendocrine tumour. Second review of the previous renal neoplasm and the cutaneous metastatic pathology showed trabecular architecture, consistent with carcinoid, but mimicking the long parallel arrays that have been described in some cases of papillary RCC.
Adjunctive vagus nerve stimulation for treatment-resistant bipolar disorder: managing device failure or the end of battery life
Authors: Pardo José V
Published: March 2016

The vagus nerve stimulation (VNS) device is used not only to treat refractory seizure disorders but also mood disorders; the latter indication received CE Mark approval in 2001 and Food and Drug Administration approval in 2005. Original estimates for the end of battery life (EOBL) were approximately 6–10 years. Many neuropsychiatric patients have or will soon face EOBL. A patient with severe, life-threatening, treatment-resistant bipolar disorder underwent 9 years of stable remission following 20 months of adjunctive VNS. The device ceased operation at EOBL. Because of logistical issues, re-initiation of VNS was delayed over several months. The patient relapsed with depression, mania and mixed states, and regained remission 17 months after device replacement. This case dictates prudence in managing stable patients in remission with VNS. If the device malfunctions, urgent surgical replacement is warranted with subsequent rapid titration to previous parameters as tolerated. Several months’ delay may trigger relapse and prove difficult to re-establish remission.
Preventing intra-urethral migration of a guidewire during antegrade placement of a JJ stent: a technical modification
Authors: Bansal Ankur , Gupta Piyush , Dalela Disha , Dalela Diwakar
Published: March 2016

A JJ stent is usually inserted in antegrade fashion after percutaneous renal surgery. We describe a new technical modification for antegrade stent insertion that prevents intraoperative intra-urethral migration of the guidewire and saves operative time and cost.
Identification, stress tolerance, and antioxidant activity of lactic acid bacteria isolated from tropically grown fruits and leaves
Authors: Fessard Amandine , Bourdon Emmanuel , Payet Bertrand , Remize Fabienne
Published: March 2016

From 6 samples of tropically grown fruits and leaves, 10 lactic acid bacteria belonging Leuconostoc, Weissella, and Lactobacillus species were isolated and identified by 16S rRNA gene sequencing and (GTG)5 fingerprinting. Acidification kinetics determined from BHI broth cultures showed genus-related patterns. In particular, Weissella cibaria appeared to act as a potent acidifier. Tolerance of isolates to acid, oxidative, or salt stress was highly variable and strain dependent. Isolate S14 (Leuconostoc pseudomesenteroides) growth was not affected by the presence of 0.05% H2O2, while Lactobacillus spp. isolates (S17 and S29) were the most tolerant to pH 4.5. The growth of 4 isolates, S5 (Leuconostoc mesenteroides), S14 and S10 (Leuconostoc pseudomesenteroides), and S27 (W. cibaria), was not affected by 5% NaCl. Nutritional beneficial properties were examined through measurement of antioxidant activities of short-term fermented pineapple juice, such as LDL oxidation and polyphenol content, and through exopolysaccharide formation from sucrose. Two isolates, S14 and S27, increased the antioxidant capacity of pineapple juice. The robust capacity of W. cibaria and of Leuconostoc pseudomesenteroides for vegetable lactic fermentation aimed to ameliorate food nutritional and functional quality was highlighted.
Impact of hydrogen forming gas annealing on microwave properties of Ba(Zn1/3Ta2/3)O3 dielectric ceramics
Authors: Sezer N. , Saka E.
Published: March 2016

The effect of H2forming gas annealing on the microwave properties of [Formula: see text] (BZT) dielectric ceramics has been studied. The structural, microwave, DC electrical and optical properties were analyzed by experiment results. With elevated temperature annealing, the microwave loss of BZT was increased. This trend correlated with high DC conductivity of annealed samples, as well as dampened phonons found in Raman spectra. These evidences, together, prove that the enhancement of oxygen vacancy defects induced by oxygen deficient sintering environment is one of the main extrinsic root causes for the high microwave loss in practical ceramic materials.
A Hybrid Skin Detection Model from Multiple Color Spaces Based on a Dual-Threshold Bayesian Algorithm
Authors: Chen Fujunku , Hu Zhigang , Li Keqin , Liu Wei
Published: March 2016

As a preliminary step of many applications, skin detection serves as an irreplaceable role in image processing applications, such as face recognition, gesture recognition, web image filtering, and image retrieval systems. Combining information from multiple color spaces improves the recognition rate and reduces the error rate because the same color is represented differently in other color spaces. Consequently, a hybrid skin detection model from multiple color spaces based on a dual-threshold Bayesian algorithm (DTBA) has been proposed. In each color space, the pixels of images are divided into three categories, namely, skin, nonskin, and undetermined, when using the DTBA. Then, nearly all skin pixels are obtained by using a specific rule that combines the recognition results from multiple color spaces. Furthermore, skin texture filtering and morphological filtering are applied to the results by effectively reducing false identified pixels. In addition, the proposed skin model can overcome interference from a complex background. The method has been validated in a series of experiments using the Compaq and the high-resolution image datasets (HRIDs). The findings have demonstrated the proposed approach produced an improvement, the true positive rate (TPR) improves more than 6% and the false positive rate (FPR) reduces more than 11%, compared with the Bayesian classifier. We confirm that the method is competitive. Meanwhile, this model is robust against skin distribution, scaling, partial occlusions, and illumination variations.
Double Stairs: A Fault-Tolerant Routing Algorithm for Networks-on-Chip
Authors: Fakhrali Saleh , Zarandi Hamid R.
Published: March 2016

Reliability is one of the main concerns in the design of networks-on-chip (NoCs) due to the use of deep submicron technologies in fabrication of such products. This paper presents a new fault-tolerant routing algorithm called double stairs for NoCs. Double stairs routing algorithm is a low overhead routing that has the ability to deal with fault. The proposed routing algorithm makes a redundant copy of each packet at the source node and routes the original and redundant packets in a new partially adaptive routing algorithm. The method is evaluated for various packet injection rates and fault rates. Experimental results show that the proposed routing algorithm offers the best trade-off between performance and fault tolerance compared to other routing algorithms, namely flooding, XYX and probabilistic flooding.
Central limit theorem for the solution to the heat equation with moving time
Authors: Liu Junfeng , Tudor Ciprian A.
Published: March 2016

We consider the solution to the stochastic heat equation driven by the time-space white noise and study the asymptotic behavior of its spatial quadratic variations with “moving time”, meaning that the time variable is not fixed and its values are allowed to be very big or very small. We investigate the limit distribution of these variations via Malliavin calculus.
What is an ideal a zero-class of?
Authors: Martins-Ferreira N. , Montoli A. , Ursini A. , Van der Linden T.
Published: March 2016

We characterise, in pointed regular categories, the ideals as the zero-classes of surjective relations. Moreover, we study a variation of the Smith is Huq condition: two surjective left split relations commute as soon as their zero-classes commute.
THREE-DIMENSIONAL GAIT ANALYSIS AS A POTENTIAL AND QUANTIFIABLE MEASUREMENT IN THE CLINICAL EVALUATION OF ANKYLOSING SPONDYLITIS
Authors: PIAO M. M. XUEMEI , XUE M. D. LUAN , JIANG M. D. SHUYUN , HU M. D. JIANDONG , LI M. M. GUOLING
Published: March 2016

The present study aimed to investigate the potential clinical value of three-dimensional gait analysis (3D-GA) system in evaluating ankylosing spondylitis (AS). Thirty-one patients with AS from September 2010 to August 2011, with 32 involved and 30 uninvolved lower limbs, were enrolled. Data of spatio-temporal parameters (step and stride length, velocity and cadence), time parameters (stance, single stance, double stance and swing phases) and kinematics parameters associated with spinal mobility (spinal lateral bending, spinal forward bending and spinal rotation) were analyzed by 3D-GA system, as well as curative effects of biologic therapy. Compared with normal values, AS patients showed decreased step and stride length ([Formula: see text]), increased cadence, longer swing and single stance phases ([Formula: see text]) and shorter stance and double stance phases ([Formula: see text]) in uninvolved lower limbs. In AS patients, reduced step length, stride length, velocity and cadence, shorter swing and single stance phases, longer stance and double stance phases ([Formula: see text]), increased lateral bending angle and decreased spinal rotation ([Formula: see text]) were detected by 3D-GA in involved lower limbs compared with uninvolved ones. In the 16 patients with decreased levels of ESR and CRP and improved ASAS scores after biology therapy, increased step length, stride length, velocity and cadence of the involved lower limbs were detected by 3D-GA ([Formula: see text]), as well as improved spinal mobility ([Formula: see text]). Hence, we concluded that 3D-GA has great potential value of clinical application for assessing and monitoring AS.
Novel User Modeling Approaches for Personalized Learning Environments
Authors: Kahraman H. Tolga , Sagiroglu Seref , Colak Ilhami
Published: March 2016

Modeling user knowledge and creating user profiles not only for special web-based social media but also for complex and mixed personalized learning environments are important research challenges. The key component for adaptation is the user’s knowledge model. This paper introduces fuzzy metric (FM)-based novel and efficient similarity measurement method and adaptive artificial neural network (AANN) and artificial bee colony (ABC)-based knowledge classification approaches for personalized learning environments. For this purpose, FM-based method has been developed to measure distances more efficiently among the users and their knowledge model using the web logs/session data. In addition, a novel knowledge classifier based on ABC and AANN having combined with the generic object model has been developed for user modeling strategies and user modeling server of adaptive educational electric course (AEEC). Finally, the approaches have been tested to compare the classification performance of the user modeling methods developed for user modeling task. The experimental results have shown that proposed methods have improved similarity measurements considerably and decreased the misclassifications in user modeling processes. Thus, powerful user modeling approaches have been presented to the literature. It is expected that the approaches introduced in this article can be a reference to others researches and to develop more adaptive and personalized web applications in future.
Characterizations of dual multiwavelet frames of periodic functions
Authors: Atreas Nikolaos D.
Published: March 2016

We prove characterizations of dual multiwavelet frames for [Formula: see text] constructed from a pair of [Formula: see text]-periodic multirefinable generators. Based on the notion of the Mixed Fundamental sequence we derive Mixed Extension Principles dictating the construction of dual wavelet masks with respect to given refinement masks and we show that these Principles characterize dual framelets.
Geometrical structures on the cotangent bundle
Authors: Popescu Liviu
Published: March 2016

In this paper, we study the geometrical structures on the cotangent bundle using the notions of adapted tangent structure and regular vector fields. We prove that the dynamical covariant derivative on [Formula: see text] fix a nonlinear connection for a given [Formula: see text]-regular vector field. Using the Legendre transformation induced by a regular Hamiltonian, we show that a semi-Hamiltonian vector field on [Formula: see text] corresponds to a semispray on [Formula: see text] if and only if the nonlinear connection on [Formula: see text] is just the canonical nonlinear connection induced by the regular Lagrangian.
The spreading fronts in a mutualistic model with delay
Authors: Li Mei
Published: March 2016

This paper is concerned with a system of semilinear parabolic equations with two free boundaries describing the spreading fronts of the invasive species in a mutualistic ecological model. The local existence and uniqueness of a classical solution are obtained and the asymptotic behavior of the free boundary problem is studied. Our results indicate that two free boundaries tend monotonically to finite or infinite limits at the same time, and the free boundary problem admits a global slow solution with unbounded free boundaries if the intra-specific competitions are strong, while if the intra-specific competitions are weak, there exist the blowup solution and global fast solution.
The role of surface functionalization of silica nanoparticles for bioimaging
Authors: Gomes Maria C. , Cunha Ângela , Trindade Tito , Tomé João P. C.
Published: March 2016

Among the several types of inorganic nanoparticles available, silica nanoparticles (SNP) have earned their relevance in biological applications namely, as bioimaging agents. In fact, fluorescent SNP (FSNP) have been explored in this field as protective nanocarriers, overcoming some limitations presented by conventional organic dyes such as high photobleaching rates. A crucial aspect on the use of fluorescent SNP relates to their surface properties, since it determines the extent of interaction between nanoparticles and biological systems, namely in terms of colloidal stability in water, cellular recognition and internalization, tracking, biodistribution and specificity, among others. Therefore, it is imperative to understand the mechanisms underlying the interaction between biosystems and the SNP surfaces, making surface functionalization a relevant step in order to take full advantage of particle properties. The versatility of the surface chemistry on silica platforms, together with the intrinsic hydrophilicity and biocompatibility, make these systems suitable for bioimaging applications, such as those mentioned in this review.
Diameter and girth of the multiplicative zero-divisor graph of multiplicative lattices
Authors: Joshi Vinayak , Sarode Sachin
Published: March 2016

In this paper, we study the multiplicative zero-divisor graph [Formula: see text] of a multiplicative lattice [Formula: see text]. Under certain conditions, we prove that for a reduced multiplicative lattice [Formula: see text] having more than two minimal prime elements, [Formula: see text] contains a cycle and [Formula: see text]. This essentially settles the conjecture of Behboodi and Rakeei [The annihilating-ideal graph of commutative rings II, J. Algebra Appl. 10(4) (2011) 741–753]. Further, we have characterized the diameter of [Formula: see text].
Generalized μ(m,n)b-open and closed functions in bigeneralized topological spaces
Authors: Donesa Methos Kristy Villar , Rara Helen Moso
Published: March 2016

The purpose of this paper is to introduce the notions of [Formula: see text]-open, [Formula: see text]-closed, quasi [Formula: see text]-open, and quasi [Formula: see text]-closed functions in bigeneralized topological spaces. Basic properties, characterizations and relationships between these functions are obtained.
Numerical method for a system of integro-differential equations by Lagrange interpolation
Authors: Jafarzadeh Yousef , Keramati Bagher
Published: March 2016

In this paper, we present the Lagrange polynomial solutions to system of higher-order linear integro-differential Volterra–Fredholm equations (IDVFE). This method transforms the IDVFE into the matrix equations which is converted to a system of linear algebraic equations. Some numerical results are given to illustrate the efficiency of the method.
Government Debt Indicators:Understanding the Data
Authors: Bloch Debra , Fall Falilou
Published: March 2016

There is no single “best” indicator for analyzing general government debt. This paper examines the various issues in defining and measuring debt, and explores other data which could be useful, both within and beyond the general government debt concept, to better track and analyze fiscal risks and sustainability issues. Measures from the broadest view of debt — gross financial liabilities — to the most comprehensive accounting of asset and liability positions — net worth — are all helpful metrics. Narrower data on specific issues such as future pension liabilities, government guarantees and debt composition are useful indicators as well. Better data reporting, including more complete metadata and broader data collection are needed to allow for an arsenal of comparable debt concepts to better anticipate future fiscal pressures.
Are House Prices Driven by Capital Flows? Evidence from Singapore
Authors: Chow Hwee Kwan , Xie Taojun
Published: March 2016

This paper investigates whether real house price appreciations can be attributed to the surge in real capital inflows into Singapore. We proxy capital flows by using the amount of Foreign Direct Investments (FDI) to real estate capturing the foreign purchases of property in Singapore which we deflate by the private residential property price index. Notwithstanding the absence of a cointegrating relationship, our results support the hypothesis that lagged short term fluctuations in capital inflows are positively associated with the growth rates of house prices over the last decade. We also provide evidence that macroprudential measures implemented by Singapore reduced the impact of capital inflows on house price appreciation by more than half, suggesting the effectiveness of such market cooling measures in weakening the credit growth channel.
Practical Limits in the Sensitivity-Linearity Trade-off for Radio Telescope Front Ends in the HF and VHF-low Bands
Authors: Tillman R. H. , Ellingson S. W. , Brendler J.
Published: March 2016

Radio telescope front ends must have simultaneously low noise and sufficiently-high linearity to accommodate interfering signals. Typically these are opposing design goals. For modern radio telescopes operating in the HF (3–30[Formula: see text]MHz) and VHF-low (30–88[Formula: see text]MHz) bands, the problem is more nuanced in that front end noise temperature may be a relatively small component of the system temperature, and increased linearity may be required due to the particular interference problems associated with this spectrum. In this paper, we present an analysis of the sensitivity-linearity trade-off at these frequencies, applicable to existing commercially-available monolithic microwave integrated circuit (MMIC) amplifiers in single-ended, differential, and parallelized configurations. This analysis and associated findings should be useful in the design and upgrade of front ends for low frequency radio telescopes. The analysis is demonstrated explicitly for one of the better-performing amplifiers encountered in this study, the Mini-Circuits PGA-103, and is confirmed by hardware measurements. We also present a design based on the Mini-Circuits HELA-10 amplifier, which is better-suited for applications where linearity is a primary concern.
Bifurcation Behavior Analysis in a Predator-Prey Model
Authors: Wang Nan , Zhao Min , Yu Hengguo , Dai Chuanjun , Wang Beibei , Wang Pengfei
Published: March 2016

A predator-prey model is studied mathematically and numerically. The aim is to explore how some key factors influence dynamic evolutionary mechanism of steady conversion and bifurcation behavior in predator-prey model. The theoretical works have been pursuing the investigation of the existence and stability of the equilibria, as well as the occurrence of bifurcation behaviors (transcritical bifurcation, saddle-node bifurcation, and Hopf bifurcation), which can deduce a standard parameter controlled relationship and in turn provide a theoretical basis for the numerical simulation. Numerical analysis ensures reliability of the theoretical results and illustrates that three stable equilibria will arise simultaneously in the model. It testifies the existence of Bogdanov-Takens bifurcation, too. It should also be stressed that the dynamic evolutionary mechanism of steady conversion and bifurcation behavior mainly depend on a specific key parameter. In a word, all these results are expected to be of use in the study of the dynamic complexity of ecosystems.
Methylchloroisothiazolinone/Methylisothiazolinone and Methylisothiazolinone Sensitivity in Hungary
Authors: Pónyai Györgyi , Németh Ilona , Temesvári Erzsébet
Published: March 2016

Background. Due to allowing of methylisothiazolinone (MI) in cosmetics, cleaning products, and paints, an epidemic of MI-hypersensitivity emerged. Patch testing Kathon CG® (3:1 mixture of methylchloroisothiazolinone and methylisothiazolinone, MCI/MI) does not correctly detect MI contact allergy, due to the low concentration of MI in the test material.Methods. A retrospective survey was performed to estimate the prevalence of MCI/MI hypersensitivity in 14693 patients tested consecutively between 1993 and 2014. Moreover, currently 314 patients were prospectively tested with the allergens MCI/MI and with MI during one year.Results. MCI/MI hypersensitivity increased retrospectively from 0.5% to 6.0%. By current prospective testing we detected 25 patients (8%) with MCI/MI and/or MI positive reactions. Out of the 25 patients 10 were only MCI/MI positive, 9 were only MI positive, and 6 were MCI/MI and MI positive. If MI had not been tested separately, MI contact allergy would have missed in 36% of all detected cases and in 2.8% of the total 314 patients.Conclusions. The frequency of MCI/MI hypersensitivity is increasing also in Hungary. We confirm that, in order to detect MI contact allergy, it needs to be tested separately. A further increase of MI hypersensitivity might be expected in the future as products containing MI are still widely available.