bluuebunny/crossref_metadata_2025 huggingface dataset:
Fracture Toughness of Samarium Cobalt Magnets
Authors: Curtin Paul R. , Constantinides Steve , Iglesias Victoria Patricia
Published: March 2016

Samarium Cobalt (SmCo) magnets have been the magnet of choice for a variety of industries for many years due to their favorable magnetic properties. Their high coercivity, combined with a low temperature coefficient, make them the ideal permanent magnet for demanding high temperature applications. One of the biggest concerns with rare earth magnets is their brittleness. Samarium Cobalt magnets in particular are prone to fracturing during machining and assembly. In manufacturing, great care must be taken to avoid chipping or fracturing these magnets due to their brittle nature.

There are two main grades of Samarium Cobalt magnets, 1:5 and 2:17. These ratios define the nominal ratio of rare earth to transition metal content.

In this paper, an investigation is performed on the fracture toughness of permanent magnets based on the Samarium Cobalt 2:17 composition. Various techniques are used to characterize the microstructure of the material, and quantify the material properties.

Optical microscopy is used to characterize the grain structure of the material and quantify the porosity of the material after sintering. By comparing the average grain size and fracture toughness of several samples, grain size was shown to not affect fracture toughness in standard material. Latent cracks in defective material showed no preference to follow grain boundaries, oxides inclusions or voids.

River marks in fracture surfaces are seen through scanning electron microscopy, confirming the transgranular cracking pattern seen by Li et al [1]This suggests that the toughness of the material is an inherent property of the main phase, not of grain boundaries or contaminants.

Samarium Cobalt magnets exhibit both mechanical and magnetic anisotropy due to the alignment of their crystal structure in the manufacturing process.

Using Palmqvist indentation crack techniques, the magnetic orientation of the grains was seen to greatly influence the direction of crack propagation from the tip of the indenter. Measurements of fracture toughness using this technique produce highly scattered data due to this anisotropic nature of the material. Specimens loaded with the indenter axis parallel to the direction of orientation show normal Palmqvist cracks, while specimens loaded perpendicular to the direction of magnetization exhibit crack propagation initiating from the faces of the indenter.

To better quantify the material’s brittleness, fracture testing is performed on specially prepared samples to obtain an absolute measure of fracture toughness (K1c). Results show that SmCo is measurably weaker than other magnetic materials such as neodymium iron boron magnets[2]. Furthermore, neither relative concentration of Samarium nor source of raw material show notable effect on the fracture toughness of the material.
Combustion Characteristics of a Swirled Burner Fueled With Waste Cooking Oil
Authors: Abdelgawad Ahmed , Emara Ahmed , Gad Mohamed , Elfatih Ahmed
Published: March 2016

Due to the intensive and extensive consumption of fossil fuels in all life sectors such as transportation, power generation, industrial processes, and residential consumption lead to find other new alternative fuels should be the target to cover this fuel demand. Fossil fuel resources are considered non-renewable sources and they will be depleted in the near future. In addition to its environmental impact which causes global warming, harmful exhaust emissions, and its price instability. Waste cooking oil (WCO) was considered as one of these alternative fuels and additives which will provide the industry with low price fuel and may solve the problem of getting rid of waste cooking oil. The present work demonstrated a comparative study for combustion characteristics between light diesel oil (LDO) and waste cooking oil in a swirled oil burner. Waste cooking oil was used directly as a fuel inside a cylindrical combustor using a swirled liquid oil burner at different operating conditions. Waste cooking oil was preheated to 90 °C before entering oil burner to decrease its viscosity and near to light diesel oil. Physical and chemical properties of waste cooking oil were measured and characterized according to ASTM standards. Combustion characteristics of this swirled oil burner using waste cooking oil and light diesel oil were experimentally investigated. Axial and radial inflame temperatures; exhaust gas emissions concentrations and combustor efficiency were analyzed. The experimental results showed that the increase of primary air pressure led to increase in exhaust gas temperature for LDO and WCO. CO2 emissions values for LDO increased compared to WCO. Hydrocarbons a emissions for WCO were higher than LDO. Percentage of heat transferred to the combustor wall increased for WCO compared to LDO. Increase of radial inflame temperature of WCO compared to LDO was due to the increase in heat release at high equivalence ratio. Waste cooking oil tended to produce luminous flames compared to diesel oil due to higher carbon content in its chemical composition.
Simulation of Heat Flux Between Two Parallel Metal Plates With Thermic Fluid as a Media
Authors: Bharambe Ganesh , Patil A. M. , Kale Sandip , Sapate Kumar Digambar , Dabeer Prakash
Published: March 2016

Most of the house hold needs are served by either the electricity or the LPG gas.[1] All fuel supply from fossil fuels seems to be limited and can generate an acute shortage in the coming future. Availability of power will be a vital problem, to be faced by future generations. Harnessing the power from solar rays seems to be the most reliable path towards sustainability of energy. The use of solar energy in the form of photovoltaic has captured a firm base in markets. However thermal energy extraction seems to be a neglected area, which has a huge potential. Hence the present paper deals with the study of extraction of such solar thermal energy using thermic fluids. With this aim, the author has initiated a study to extract the heat from solar concentrated power (CSP) systems. This system will heat the thermic fluid due to thermal energy in solar rays. This hot fluid is then passed through a guided passages formed between two plates and is used for heating top and bottom surfaces of two metallic plates. These hot surfaces then can be used as source of energy for home and industrial purposes. However in the present experimentation work, the scope of work is limited to thermal heat handling through the plate surfaces. Hence the supply of thermal energy from CSP is equivalently replaced by electric heater/ gas burners and is not discussed in details.

Different flow passages are considered for result generation. Computational Fluid Dynamics (CFD) using FLUENT as tool in ANSYS 14.5 software is used for studying and comparing the results. Mathematical model is generated using preselected option of passage. Further Experimental validation is sorted in the end to verify the above results with temperature of upto 150°C. Selection of heat transfer fluid is based on sustainable higher operating temeperature. Pressure drop across the oil passage has indicated the inherent energy losses of the system. With the use of flow control valve and hydraulic pump the flow through the passage is regulated. Thus the energy flow can be controlled with respect to the requirement of process being carried out at each of the top and bottom surface respectively.
Biomechanics Aspects for Silastic Implant Arthroplasty Simulation of the First Metatarsophalangeal Joint
Authors: Martínez Bocanegra Marco A. , Bayod Lopez Javier , Vidal-Lesso A. , Becerro de Bengoa Vallejo Ricardo , Lesso Arroyo Raúl , Hernández Humberto Corro
Published: March 2016

This work focuses on the biomechanical simulation of surgery for total replacement of the first metatarsophalangeal joint (MTPJ) allowed us to identify and analyze several key aspects for finite element simulation of hallux rigidus pathology. Predicting the optimal response of a finite element model (FEM) depends on proper characterization. At this part of the work, those conditions that have a direct or indirect influence on the model that can change its behavior should be considered.

For this purpose, we presented in this work a finite element model which include 26 bones: 14 phalanges, 5 metatarsals, 3 cuneiform bones, 1 cuboid, 1 navicular, 1 talus and 1 calcaneus, all of them include articular cartilage. In addition, the model also considers: thin ligaments, long ligaments, muscles and a joint implant.

Loads and boundary conditions included: a pretension in the flexor caused by position analysis, a distributed load in the talus in its normal and tangential component, a restriction of movement of some points in the phalanges and calcaneus and the contact conditions between flexor and extensor created from surfaces in the bone volumes.

Moreover, the selection of support and constrains regions in the phalanges and calcaneus area must be carefully selected to reproduce the conditions of real support and interaction with adjacent tissues not simulated. These conditions have influence in the structural biomechanical response of each tissue and in contact regions, leading to unexpected behavior if they are wrong selected. In addition, results showed that care must be taken in the mechanical characterization of each tissue, selecting the mechanical properties, pretension, geometry and critical position according to in vitro results or MRIs.

Biomechanical aspects reported in this work allow to take into account fundamental details to improve future simulations of this pathology as well as to improve the correlation with experimental results. These biomechanical aspects provide knowledge for finite element simulation of the arthroplasty for the first metatarsophalangeal joint, this allow us to generate a virtual model for arthroplasty of the hallux rigidus to predict, prevent and improve surgical techniques for implantation of prostheses in the first metatarsophalangeal joint.
Mobile Robot Coordinated Platooning: A Small-Scale Experimental Evaluation to Emulate Connected Vehicles
Authors: Goli Mohammad , Eskandarian Azim
Published: March 2016

This paper presents the problem of mobile robots specialized coordinated motion, namely platooning from an experimental point of view. An experimental set-up consisting of multiple mobile robots is developed to emulate a scaled version of real life connected vehicles which will move in a platoon formation for enhanced efficiency, safety, and energy conservations. The autonomous motion of multiple robots could be coordinated through wireless communications between them and a lead robot. Different aspects and requirements of an experimental platform to accomplish this mission are discussed. A platooning scenario using our connected mobile robots is demonstrated in this paper. The efficiency of the described platform in implementing vehicle platooning strategies and the behavior of propagation error when there is no communication between robots is observed from this experiment.
Experimental Determination of the Mass Moment of Inertia of a Flywheel Using Dynamics and Statistical Methods
Authors: Hassanpour Pezhman , Weaser Monica , Colquhoun Ray , Alghemlas Khaled , Alrashdan Abdullah
Published: March 2016

This paper presents the analysis of the mass moment of inertia (MMI) of a flywheel using experiment data. This analysis includes developing two models for determining the MMI of the flywheel. The first model considers the effect of mass moment of inertia only, while the second model takes the effect of friction in the ball bearings into consideration. The experiment results have been used along with both models to estimate the MMI of the flywheel. It has been demonstrated that while the model with no friction can be used for estimating the MMI to some extent, the model with friction produces the most accurate result. On the other hand, an effective application of the model with friction requires several experimental measurements using different standard masses. This translates into more expensive method in terms of experiment time and equipment cost.
Comparative Operation of Small Vuilleumier Cryocoolers Under Isothermal and Adiabatic Conditions
Authors: Rogdakis E. , Dogkas G.
Published: March 2016

Vuilleumier refrigerators capable of reaching cryogenic temperatures have been developed over the past years. A thermodynamic analysis can provide useful results concerning the energy quantities involved in this type of cryocoolers.

Comparison of an isothermal and an adiabatic model yields the differences of the performance under each condition. Adiabatic cooling capacity is higher than the isothermal, but the COP decreases. Additionally, the temperatures of the heat exchangers that reject heat and produce the cooling effect, affect the capacity and the performance of the cryocooler in opposite way. Furthermore, the cooling capacity is dependent on the pressure inside the machine and its speed, but the performance is not affected by these variables.
Similarity Scaling of Vuilleumier Heat Pumps
Authors: Rogdakis E. , Dogkas G.
Published: March 2016

Previous works on scaling methods for Stirling and regenerative machines, have yielded interesting results about the prediction of the performance of the machine. Information from existing Vuilleumier heat pump is utilized for a scaling correlation. Geometric and dynamic variables are selected for scaling investigation in terms of thermodynamic characteristics such as heat power input or heat power gain. This is accomplished with the aid of a specially developed computer program.

In addition, energy dissipation due to pressure drop, losses across the heat exchangers walls and thermally ineffective regenerators are introduced and the performance of the Vuilleumier heat pump is reevaluated. A combination of scaling factors with two or more dynamic variables is derived for a deeper examination of scaling influences.
Dynamic Analysis of a Cylindrical Roller Bearing With Time-Varying Localized Defects on Raceways
Authors: Wang Fengtao , Chen Li , Liu Heng , Jing Minqing , Chen Wei , Wu Tonghai , Liu Yi
Published: March 2016

An existing defect on the bearing raceway may evolve with the interactions between the bearing elements, and the evolutions of the defect may be divided into different stages. In this study, a dynamic model for a cylindrical roller bearing with localized defects on raceways is developed to investigate vibration character of the bearing in these stages. The coupling of centrifugal forces, gravity forces and the slipping of the roller are considered. The half sine function and step function are used to construct time-varying models of defects in different stages, which is reflected on the local deflection. The system dynamic equations are solved by the fourth-order Runge-Kutta integration method with variable steps. Time domains and frequency domains are used to analyze dynamic responses of the bearing in every defect stage, which can be used as a reference of fault diagnosis. An experimental comparison in the previous study is carried out to validate the proposed model.
A Low-Dissipation Second-Order Upwind Flux Formulation for Simulation of Complex Turbulent Flows
Authors: Poe Nicole M. W. , Walters D. Keith , Luke Edward A. , Morris Christopher I.
Published: March 2016

A numerical method is presented for low-dissipation, high-resolution finite-volume CFD simulations of turbulent flow. The convective fluxes in the governing equations are computed using a conventional upwind-biased second order scheme, with a modified linear reconstruction of face states from neighboring cells. The new scheme, dubbed optimization-based gradient reconstruction (OGRE), incorporates two key enhancements to improve performance. The first is an iterative least-square gradient computation procedure which minimizes the second-order dissipative error contribution to the face reconstruction on structured Cartesian meshes. The second is a slope limiting scheme which enforces local monotonicity near discontinuities without the detrimental effect of limiting in smooth regions of the flowfield. In addition, for density-based methods employing flux-difference splitting for the convective terms, a recently proposed weighted-average for obtaining the reconstructed face variable values is used, which improves accuracy in subsonic flow regions and eliminates the need for preconditioning. The new method has been implemented into the Ansys FLUENT and Loci-CHEM flow solvers, and is validated for several test cases by comparison to a conventional linear reconstruction implementation. Results clearly show the advantage of the new scheme over conventional upwind-biased second order schemes in terms of accuracy, particularly with regard to LES/DNS simulation. The most significant improvement is obtained for Cartesian meshes and low Mach number flows, but all test cases showed some level of improvement using the new scheme. The method is also quantified in terms of increased computational cost versus traditional methods. Based on results shown here, the method appears to represent a viable alternative to currently used centered and blended schemes in terms of accuracy, robustness, and computational expense.
Structural Reliability of Novel 3-D Integrated Thermal Packaging for Power Electronics
Authors: Khanna S. , McCluskey P. , Manno M. , Bar-Cohen A. , Yang B. , Ohadi M.
Published: March 2016

The continual increase of device power and package integration levels has driven the development of advanced power electronics packaging solutions. This study will focus on a numerical modeling approach to design analysis and material selection to improve solder joint reliability in one of these advanced solutions — a thermally integrated power electronics package that aims to dissipate hot-spot heat flux (5 kW/cm2) via mini-contact based thermo-electric (TE) cooling in addition to removing background heat flux (1 kW/cm2) by manifold-microchannel cooling. The methodology used for performing the structural reliability modeling is a non-linear finite element analysis (FEA) approach. Combined thermal and mechanical analyses were run to obtain stresses and strains in the solder joint used to integrate the TE cooler with the mini-contact and the mini-contact with the Silicon Carbide (SiC) chip. To predict the Mean Time to Failure (MTTF) of SAC305 at various levels of integration, a Physics of Failure (PoF) based methodology was applied using Engelmaier’s failure model.

In this paper, we will discuss the results of analyses of tapered, t-shaped, and lofted shaped mini-contacts made out of SiC, copper and diamond. Both structural design and material selection affect hot-spot heat dissipation and solder joint reliability. SiC has a good thermal conductivity at room temperature (RT), however, with increase in temperature, its thermal conductivity drops, and this can adversely affect device performance in high temperature applications. On the other hand, one can take advantage of high conductivity materials like copper, diamond or silver-diamond composite to keep the device cool and thus, improve package life time. However, for such high conductivity materials, one will need to take into account the cost of manufacturing complex shapes without any compromise in package thermal or reliability performance.

It was found that a ductile mini-contact material will share the thermal mismatch strain with the solder interconnection, while a brittle mini-contact material will shift the failure site inside the TE cooler. It was determined that a mini-contact structure tapered near its top base and lofted (constant cross-sectional area) near the chip (bottom base) would provide the best reliability results. Application of high conductivity composite material (silver-diamond composite) to enhance structural reliability is discussed.
Comparison Between the Coal-Fired Power Plant With CO2 Capture by Integrating MCFCs System and the Integrated Gasification Combined Cycle System Integrated MCFCs
Authors: Bian Jing , Sun Siyu , Xia Kun , Duan Liqiang , Desideri Umberto , Yang Yongping
Published: March 2016

In this paper the coal-fired power plant with CO2 capture by integrating MCFCs system and the integrated coal gasification with CO2 capture by integrating MCFCs combined cycle system are compared with each other in different ways. The effects of the key parameters of MCFC on the performance of two systems, such as CO2 utilization factor, fuel utilization factor and the current density of MCFC, have been analyzed and compared. Aspen Plus soft is used to develop the system models and the key parameters of MCFC are calculated, analyzed and optimized. The flue gas of the coal-fired power plant (CFPP) or the Integrated Gasification Combined Cycle (IGCC) system is used as the reactant gas of MCFC cathode side, reacting with fuel in the anode side and producing power. The anode exhaust gas burns with pure oxygen in the afterburner. The CO2 in the flue gas is further concentrated and captured with the lower energy consumption. The results show that, the efficiency of the coal-fired power plant integrating MCFCs system is about 45.75% when the CO2 capture rate is 88.07%, and the efficiency of the IGCC system integrating MCFCs is about 47.31% when the CO2 capture rate is 88.14%. Achievements in this paper will provide the valuable reference for CO2 capture of coal-fired power plant and IGCC with low energy penalty.
Color Emotion Under LED Light System Controlling Color Rendering Property
Authors: Watanuki Keiichi , Shinoda Hiroshi , Muramatsu Keiichi
Published: March 2016

Emotional responses to color stimuli are referred to as color emotions, and relationships between color attributes and them have been discussed in past studies. In the current study, we reveal relationships between color rendering properties and color emotions to provide a light system controlling color emotions along with color rendering property. We developed such a system and conducted two evaluations of the system performance and color emotions under the light generated by the system. The system we developed in the current study has four color (red, green, blue, and yellow) LEDs to enrich color rendering property.

In addition, we conducted a subjective assessment to explore relationships between color emotions and color rendering properties. In the assessment, we studied color emotions against facial skin irradiated by various illuminants with different color rendering properties. We prepared sixteen different light conditions and the participants of the study were asked to respond to the stimuli with fifteen Likert scales. As a result, we confirmed that the color rendering property certainly affects color emotions, and we obtained regression models to represent color emotions by color rendering properties. Furthermore, we found that male and female test subjects experience different color emotions based on skin color.
Reduction of Nanowire Agglomeration via an Intermediate Membrane in Nanowires Preparation for Nanosensors Application
Authors: Beheshti Mohammad , Park Sunggook , Choi Junseo , Geng X. , Podlaha-Murphy Elizabeth
Published: March 2016

Nanowires are widely used as sensing components for lab-on-a-chip devices. One major problem in utilizing pre-grown nanowires in lab-on-a-chip applications is the agglomeration of nanowires during their preparation process. The common methods to reduce the agglomeration of nanowires include stirring, sonication and using of surfactants. However, these methods break the long nanowires and are not efficient to produce enough single nanowires. This paper shows a new method to improve the deposition process of individual nanowires. An intermediate membrane was used for the deposition of the nanowires after their preparation process. The membrane helps to filter the nanowire agglomerates and to deposit separated individual nanowires over a silicon surface underneath. The study also shows that the number of single nanowires is increased by increasing the tilt angle of the membrane. The method also helps achieving single long nanowires.
Aerodynamic Performance Analysis of a Bobsleigh Body Shape
Authors: Shim Hyeon-Seok , Jung Hyo-Yeon , Kim Kwang-Yong
Published: March 2016

Aerodynamic performance of a bobsleigh is one of the most important factors in reducing the race time. In this study, an investigation on the aerodynamic characteristics of a bobsleigh has been performed using three-dimensional Reynolds-averaged Navier-Stokes equations with the k-ε turbulence model. An unstructured tetrahedral grid system was constructed in the computational domain, and the optimal number of grids was selected through a grid-dependency test. The major axis length and thickness of ellipse-shaped front bumper, and the radii of the cowling on side and front views, were selected as four geometric parameters to be tested, and the drag coefficient was considered as an aerodynamic performance parameter. It was found that the drag coefficient was more sensitive to the thickness of the front bumper and the radius of the cowling on side view of the bobsleigh than on the other parameters.
Adenoviral Expression of a Bispecific VHH-Based Neutralizing Agent That Targets Protective Antigen Provides Prophylactic Protection from Anthrax in Mice
Authors: Moayeri Mahtab , Tremblay Jacqueline M. , Debatis Michelle , Dmitriev Igor P. , Kashentseva Elena A. , Yeh Anthony J. , Cheung Gordon Y. C. , Curiel David T. , Leppla Stephen , Shoemaker Charles B.
Published: March 2016

Bacillus anthracis
, the causative agent of anthrax, secretes three polypeptides, which form the bipartite lethal and edema toxins (LT and ET, respectively). The common component in these toxins, protective antigen (PA), is responsible for binding to cellular receptors and translocating the lethal factor (LF) and edema factor (EF) enzymatic moieties to the cytosol. Antibodies against PA protect against anthrax. We previously isolated toxin-neutralizing variable domains of camelid heavy-chain-only antibodies (VHHs) and demonstrated their
in vivo
efficacy. In this work, gene therapy with an adenoviral (Ad) vector (Ad/VNA2-PA) (VNA, VHH-based neutralizing agents) promoting the expression of a bispecific VHH-based neutralizing agent (VNA2-PA), consisting of two linked VHHs targeting different PA-neutralizing epitopes, was tested in two inbred mouse strains, BALB/cJ and C57BL/6J, and found to protect mice against anthrax toxin challenge and anthrax spore infection. Two weeks after a single treatment with Ad/VNA2-PA, serum VNA2-PA levels remained above 1 μg/ml, with some as high as 10 mg/ml. The levels were 10- to 100-fold higher and persisted longer in C57BL/6J than in BALB/cJ mice. Mice were challenged with a lethal dose of LT or spores at various times after Ad/VNA2-PA administration. The majority of BALB/cJ mice having serum VNA2-PA levels of >0.1 μg/ml survived LT challenge, and 9 of 10 C57BL/6J mice with serum levels of >1 μg/ml survived spore challenge. Our findings demonstrate the potential for genetic delivery of VNAs as an effective method for providing prophylactic protection from anthrax. We also extend prior findings of mouse strain-based differences in transgene expression and persistence by adenoviral vectors.
Poppers retinopathy
Authors: Luis Joshua , Virdi Meena , Nabili Shahriar
Published: March 2016

We present a case of a 52-year-old man with sudden, bilateral central loss of vision as a result of inhalation of ‘poppers’. He was found to have characteristic changes on optical coherence tomography. With conservative treatment, the patient's vision improved marginally at 3 months follow-up. An overview of previous published cases is also included.
Upper Middle to lower Upper Ordovician chitinozoans and conodonts from the Bliudziai-150 core, southern Lithuania
Authors: Stouge Svend , Bauert Garmen , Bauert Heikki , Nõlvak Jaak , Rasmussen Jan A.
Published: March 2016

Integration of chitinozoan and conodont biozones is based on detailed collections from the Bliudziai-150 well, southern Lithuania, that penetrated upper Darriwilian – lower Sandbian sedimentary carbonate rocks. The strata accumulated at the southeastern side of the Livonian Tongue and represent the transition from shallow shelf facies of the Lithuanian shallow-water shelf facies belt to the deeper-water shelf facies belt. Systematically collected and closely spaced samples of the carbonates from the Bliudziai-150 core yielded both chitinozoans and conodonts in abundance. The chitinozoans are assigned to the Laufeldochitina striata, Laufeldochitina stentor, Angochitina curvata – Armoricochitina granulifera, Lagenochitina dalbyensis, Belonechitina hirsuta, and Spinachitina cervicornis chitinozoan biozones, and the conodonts are assigned to the Pygodus serra Zone (with three subzones), Pygodus anserinus Zone (with two subzones), and the three subzones of the Amorphognathus tvaerensis Zone. The fossils are clearly of Baltoscandian affinity, and the integrated results support existing knowledge concerning the biostratigraphy of the two groups in Baltoscandia. Thus, the studied interval is confidently assigned to the Lasnamägi, Uhaku, Kukruse, and Haljala regional stages of the East Baltic regional chronostratigraphical scheme, corresponding to the global upper Darriwilian – lower Sandbian stages (Middle to Upper Ordovician). International correlation of the chitinozoan and conodont succession is presented, and the position of the base of the international Sandbian Stage is placed at 1380.00 m in the Bliudziai-150 core. A horizon marked by multiple discontinuity surfaces represents the base of Kegel depositional sequence and coincides with the appearance of Armoricochitina granulifera, Angochitina curvata, Lagenochitina dalbyensis, and Baltoniodus gerdae in the Bliudziai-150 core.
Two-faced families of non-commutative random variables having bi-free infinitely divisible distributions
Authors: Gao Mingchu
Published: March 2016

We study two-faced families of non-commutative random variables having bi-free (additive) infinitely divisible distributions. We prove a limit theorem of the sums of bi-free two-faced families of random variables within a triangular array. As a corollary of our limit theorem, we get Voiculescu’s bi-free central limit theorem. Using the full Fock space operator model, we show that a two-faced pair of random variables has a bi-free (additive) infinitely divisible distribution if and only if its distribution is the limit distribution in our limit theorem. Finally, we characterize the bi-free (additive) infinite divisibility of the distribution of a two-faced pair of random variables in terms of bi-free Levy processes.
The Maaß space and Hecke operators
Authors: Gallenkämper Jonas , Heim Bernhard , Krieg Aloys
Published: March 2016

We give a new proof of the fact that the Maaß space is invariant under all Hecke operators. It is based on the characterization of the Maaß space by a symmetry relation and certain commutation relations of the Hecke algebra for the Jacobi group.
QCD breaks Lorentz invariance and colour
Authors: Balachandran A. P.
Published: March 2016

In the previous work [A. P. Balachandran and S. Vaidya, Eur. Phys. J. Plus 128, 118 (2013)], we have argued that the algebra of non-Abelian superselection rules is spontaneously broken to its maximal Abelian subalgebra, that is, the algebra generated by its completing commuting set (the two Casimirs, isospin and a basis of its Cartan subalgebra). In this paper, alternative arguments confirming these results are presented. In addition, Lorentz invariance is shown to be broken in quantum chromodynamics (QCD), just as it is in quantum electrodynamics (QED). The experimental consequences of these results include fuzzy mass and spin shells of coloured particles like quarks, and decay life times which depend on the frame of observation [D. Buchholz, Phys. Lett. B 174, 331 (1986); D. Buchholz and K. Fredenhagen, Commun. Math. Phys. 84, 1 (1982; J. Fröhlich, G. Morchio and F. Strocchi, Phys. Lett. B 89, 61 (1979); A. P. Balachandran, S. Kürkçüoğlu, A. R. de Queiroz and S. Vaidya, Eur. Phys. J. C 75, 89 (2015); A. P. Balachandran, S. Kürkçüoğlu and A. R. de Queiroz, Mod. Phys. Lett. A 28, 1350028 (2013)].

In a paper under preparation, these results are extended to the ADM Poincaré group and the local Lorentz group of frames. The renormalisation of the ADM energy by infrared gravitons is also studied and estimated.
New results at LHC confirming the vacuum stability and Multiple Point Principle
Authors: Laperashvili L. V. , Nielsen H. B. , Das C. R.
Published: March 2016

In the present paper we argue that the correction to the Higgs mass coming from the bound state of 6 top and 6 antitop quarks, predicted early by Froggatt and ourselves, leads to the Standard Model vacuum stability and confirms the accuracy of the multiple point principle (principle of degenerate vacua) for all experimentally valued parameters (Higgs mass, top-quark mass, etc.). Fitting to get the vacuum degeneracy requires a mass of the bound state, just in the region of the new two photon state in Large Hadron Collider, 750–760 GeV.
RG flow of AC conductivity in soft wall model of QCD
Authors: Bhatnagar Neha , Siwach Sanjay
Published: March 2016

We study the Renormalization Group (RG) flow of AC conductivity in soft wall model of holographic QCD. We consider the charged black hole metric and the explicit form of AC conductivity is obtained at the cutoff surface. We plot the numerical solution of conductivity flow as a function of radial coordinate. The equation of gauge field is also considered and the numerical solution is obtained for AC conductivity as a function of frequency. The results for AC conductivity are also obtained for different values of chemical potential and Gauss–Bonnet couplings.
Low Input Current Ripple Quasi-Single-Stage Power Supply Based on Double Resonant Tank LLC Converter for Maglev Control System Applications
Authors: Ma Hongbo , Yi Junhong , Shuai Jie , Yang Jie
Published: March 2016

High input voltage, multiple low voltage outputs and high working temperature are the main design challenges for magnetic levitation (maglev) control power supply. The traditional solutions have several problems, such as the uncontrolled duty ratio, the poor cross-regulation capability and low reliability. In order to solve these problems, a quasi-single-stage solution employing the double resonant tank LLC topology is proposed and developed in this paper. The proposed solution can increase significantly the overall conversion efficiency because of the achieved soft-switching over the entire operation range. Moreover, the low input current ripple, high magnetic utilization and high reliability can be achieved. Experimental results of a 210-W laboratory prototype with 220–380[Formula: see text]V input and four outputs are presented to demonstrate the declared features.
Efficient Parallel Architecture for Fixed-Coefficient and Variable-Coefficient FIR Filters Using Distributed Arithmetic
Authors: Singhal Subodh Kumar , Mohanty Basant Kumar
Published: March 2016

In this paper, we performed the complexity analysis of fixed-coefficient and variable-coefficient distributed arithmetic (DA)-based finite impulse response (FIR) filter structures to observe the effect of LUT decomposition on the area complexity of DA structure. The complexity analysis reveals that the area complexity of different units of DA FIR filter structure does not increase proportionately with the level of parallelism. An appropriate selection of LUT decomposition factor, and introducing higher level of parallelism in the computation could improve the area-delay efficiency of both fixed-coefficient and variable-coefficient DA-based FIR structures. Based on these findings, we have proposed bit-parallel block-based DA structures, for fixed-coefficient and variable-coefficient FIR. The proposed structures process one block of input samples and produce one block of outputs in every clock cycle. Theoretical estimate shows that the proposed fixed-coefficient structure, for block-size 8 and filter-length 32, involves eight times more ROM-LUT words, eight times more adders, two less registers, and offers eight times higher throughput-rate than the existing similar structure. For the same block-size and filter-length, the proposed variable-coefficient structure involves 7.2 times more adders, the same number of registers, eight times more MUXes, and offers eight times higher throughput than the best available similar structure. Synthesis result shows that the proposed fixed-coefficient structure for block-size 8 and filter-length 32 involve 47% less area delay product (ADP) and 42% less energy per sample (EPS) than the existing structure and offers nearly eight times higher throughput than others. For the same block-size and filter-length, the proposed structure for variable-coefficient FIR involves 71% less ADP and 65% less EPS than the similar existing structures.
Power counting for nuclear forces in chiral effective field theory
Authors: Long Bingwei
Published: March 2016

The present note summarizes the discourse on power counting issues of chiral nuclear forces, with an emphasis on renormalization-group invariance. Given its introductory nature, I will lean toward narrating a coherent point of view on the concepts, rather than covering comprehensively the development of chiral nuclear forces in different approaches.
Surface layer effect on nuclear deformation energy
Authors: Kolomietz V. M. , Sanzhur A. I. , Reznychenko B. V.
Published: March 2016

In this paper, we apply the direct variational method to derive the nuclear deformation energy. The extended Thomas–Fermi approximation (ETFA) for the energy functional with Skyrme forces is used. We study the influence of the finite surface layer of the nuclear density profile function on the formation of the fission barrier and the scission configuration. Comparison of the variational approach with the traditional liquid drop model (LDM) is presented. We show the sensitivity of the numerical results to the surface diffuseness parameter.
Possible interrelations among chemical freeze-out conditions
Authors: Tawfik A. , El-Bakry M. Y. , Habashy D. M. , Mohamed M. T. , Abbas E.
Published: March 2016

At thermal equilibrium, different chemical freeze-out conditions have been proposed so far. They have an ultimate aim of proposing a universal description for the chemical freeze-out parameters ([Formula: see text] and [Formula: see text]), which are to be extracted from the statistical fitting of different particle ratios measured at various collision energies with calculations from thermal models. A systematic comparison between these conditions is presented. The physical meaning of each of them and their sensitivity to the hadron mass cuts are discussed. Based on availability, some of them are compared with recent lattice calculations. We found that most of these conditions are thermodynamically equivalent, especially at small baryon chemical potential. We propose that further crucial consistency tests should be performed at low energies. The fireball thermodynamics is another way of guessing conditions describing the chemical freeze-out parameters extracted from high-energy experiments. We endorse the possibility that the various chemical freeze-out conditions should be interpreted as different aspects of one universal condition.
DFT MODELING OF BENZOYL PEROXIDE ADSORPTION ON α-Cr2O3(0001) SURFACE
Authors: MALDONADO FRANK , STASHANS ARVIDS
Published: March 2016

Density functional theory (DFT) within the generalized gradient approximation (GGA) has been used to investigate possible adsorption configurations of benzoyl peroxide (BPO) molecule on the chromium oxide ([Formula: see text]-Cr2O[Formula: see text] (0001) surface. Two configurations are found to lead to the molecular adsorption with corresponding adsorption energies being equal to [Formula: see text]0.16 and [Formula: see text]0.48[Formula: see text]eV, respectively. Our work describes in detail atomic displacements for both crystalline surface and adsorbate as well as discusses electronic and magnetic properties of the system. The most favorable adsorption case is found when the chemical bond between one of the molecular oxygens and one of the surface Cr atoms has been formed.
Construction of Levi processes on path spaces of Lie groups
Authors: Kalinichenko A. A.
Published: March 2016

Given a compact Lie group and a conjugate-invariant Levi process on it, generated by the operator [Formula: see text], we construct the Levi process on the path space of [Formula: see text], associated with the convolution semigroup [Formula: see text] of probability measures, where [Formula: see text] is the distribution of the Levi process on [Formula: see text] generated by [Formula: see text]. The constructed process is obtained as the weak limit of piecewise constant paths, which, as well as proving its existence and properties, provides finite-dimensional approximations of Chernoff type to the integrals with respect to its distribution.
On function field Mordell–Lang and Manin–Mumford
Authors: Benoist Franck , Bouscaren Elisabeth , Pillay Anand
Published: March 2016

We give a reduction of the function field Mordell–Lang conjecture to the function field Manin–Mumford conjecture, for abelian varieties, in all characteristics, via model theory, but avoiding recourse to the dichotomy theorems for (generalized) Zariski geometries. Additional ingredients include the “Theorem of the Kernel”, and a result of Wagner on commutative groups of finite Morley rank without proper infinite definable subgroups. In positive characteristic, where the main interest lies, there is one more crucial ingredient: “quantifier-elimination” for the corresponding [Formula: see text] where [Formula: see text] is a saturated separably closed field.
Consensus properties and their large-scale applications for the gene duplication problem
Authors: Moon Jucheol , Lin Harris T. , Eulenstein Oliver
Published: March 2016

Solving the gene duplication problem is a classical approach for species tree inference from gene trees that are confounded by gene duplications. This problem takes a collection of gene trees and seeks a species tree that implies the minimum number of gene duplications. Wilkinson et al. posed the conjecture that the gene duplication problem satisfies the desirable Pareto property for clusters. That is, for every instance of the problem, all clusters that are commonly present in the input gene trees of this instance, called strict consensus, will also be found in every solution to this instance. We prove that this conjecture does not generally hold. Despite this negative result we show that the gene duplication problem satisfies a weaker version of the Pareto property where the strict consensus is found in at least one solution (rather than all solutions). This weaker property contributes to our design of an efficient scalable algorithm for the gene duplication problem. We demonstrate the performance of our algorithm in analyzing large-scale empirical datasets. Finally, we utilize the algorithm to evaluate the accuracy of standard heuristics for the gene duplication problem using simulated datasets.
The Effect of the Fit Between Product Architecture and Competitive Action on Business Performance: An Empirical Study of the Taiwan IT Industry
Authors: Yung Ing-Shane , Tsai Chin-Fa
Published: March 2016

This study combines product architecture and competitive action by using a survey of the Taiwan IT industry. The analytic framework is applied to the theory of situational management to observe whether there is a good fit between product architecture (modular or integral), and inter-firm competitive action (homogeneous or heterogeneous), which corresponds to the level of business performance. This study thus seeks an in-depth understanding of the relationship between product architecture and competitive action, as well as confirmation for the development direction and competitive model of Taiwan’s IT industry, where some important characteristics have been found. First, to establish the competitive advantages, the product architecture needs to match the competitive action. Second, a firm usually adopts homogeneous action when its product architecture tends to be modular products; inversely, it usually adopts heterogeneous action when its product architecture tends to be integral products. Third, homogeneous competitive action has a mediating effect on modular architecture and business performance. Overall, this study provides a theoretical analytic framework to better understand the interactive relationship between product architecture and competitive action.
Development of Simple and Effective Dual-Readout Sensor Based on Gold Nanoparticles and Cadmium Telluride Quantum Dots for Cartap Analysis
Authors: Wu Huixiang , Hou Changjun , Fa Huanbao , Dong Liang , Ma Yi , Yang Mei , Shen Caihong , Zhou Jun , Huo Danqun
Published: March 2016

Cartap is among the most popular pesticides that are widely used to boost food production, however, its residues pose a great threat to human health and the environment. We presented simple and effective colorimetric sensor based on aggregation of gold nanoparticles (AuNPs) with appropriate diameter and fluorescent sensor via inner filter effect (IFE) of AuNPs on cadmium telluride quantum dots (CdTe QDs), respectively. Firstly, effect of diameter of AuNPs was investigated and the results indicated that AuNPs with diameter of 13[Formula: see text]nm (AuNPs[Formula: see text] showed better sensitivity toward cartap. Thus, AuNPs[Formula: see text] was chosen for colorimetric and fluorescent cartap assay. On one hand, mercaptoacetic acid (MA) was functionalized on AuNPs[Formula: see text] for the improvement of anti-disturbance ability for discrimination study. A decent linear relationship for cartap was obtained in the range from 1[Formula: see text][Formula: see text]M to 50[Formula: see text][Formula: see text]M with detection limit of 1.32[Formula: see text][Formula: see text]M for colorimetric readout; on the other hand, fluorescent sensor based on AuNPs[Formula: see text] displayed excellent linear relationship with cartap concentration varying from 20[Formula: see text]nM to 100[Formula: see text]nM with low detection limit of 4.02[Formula: see text]nM. And the above-mentioned sensor showed acceptable anti-disturbance ability for cartap discrimination. These results demonstrated that the sensor as-developed would be a great potential candidate for cartap detection in real application.
Dynamics on tumor immunotherapy model with periodic impulsive infusion
Authors: Zhu Huiyan , Ding Qian , Wang Fangjuan , Wang Huilan
Published: March 2016

A periodic pulse differential equation model of tumor immunotherapy is established by considering the periodic and transient behavior of infusing immune cells. Using comparison theorem and Floquet multiplier theory of the impulsive differential equation, the boundedness of the model solution, the existence and stability of the free-tumor periodic solution are given. Furthermore, the persistence of the system is analyzed. Numerical simulations are carried to confirm the main theorems.
On the decay of the smallest singular value of submatrices of rectangular matrices
Authors: Liu Yang , Wang Yang
Published: March 2016

In this paper, we study the decay of the smallest singular value of submatrices that consist of bounded column vectors. We find that the smallest singular value of submatrices is related to the minimal distance of points to the lines connecting other two points in a bounded point set. Using a technique from integral geometry and from the perspective of combinatorial geometry, we show the decay rate of the minimal distance for the sets of points if the number of the points that are on the boundary of the convex hull of any subset is not too large, relative to the cardinality of the set. In the numeral or computational aspect, we conduct some numerical experiments for many sets of points and analyze the smallest distance for some extremal configurations.