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We determine the shear viscosity of a hot and dense Yukawa-Fermi gas, using the standard Green-Kubo relation, according to which the shear viscosity is given by the retarded correlator of the traceless part of viscous energy-momentum tensor. We approximate this retarded correlator using a one-loop skeleton expansion, and express the bosonic and fermionic shear viscosities, $\eta_{b}$ and $\eta_{f}$, in terms of bosonic and fermionic spectral widths, $\Gamma_{b}$ and $\Gamma_{\pm}$. Here, the subscripts $\pm$ correspond to normal and collective (plasmino) excitations of fermions. We study, in particular, the effect of these excitations on thermal properties of $\eta_{f}[\Gamma_{\pm}]$. To do this, we determine first the dependence of $\Gamma_{b}$ and $\Gamma_{\pm}$ on momentum $p$, temperature $T$, chemical potential $\mu$ and $\xi_{0}\equiv m_{b}^{0}/m_{f}^{0}$, in a one-loop perturbative expansion in the orders of the Yukawa coupling. Here, $m_{b}^{0}$ and $m_{f}^{0}$ are $T$ and $\mu$ independent bosonic and fermionic masses, respectively. We then numerically determine $\eta_{b}[\Gamma_{b}]$ and $\eta_{f}[\Gamma_{\pm}]$, and study their thermal properties. It turns out that whereas $\Gamma_{b}$ and $\Gamma_{+}$ decrease with increasing $T$ or $\mu$, $\Gamma_{-}$ increases with increasing $T$ or $\mu$. This behavior qualitatively changes by adding thermal corrections to $m_{b}^{0}$ and $m_{f}^{0}$, while the difference between $\Gamma_{+}$ and $\Gamma_{-}$ keeps increasing with increasing $T$ or $\mu$. Moreover, $\eta_{b}$ ($\eta_{f}$) increases (decreases) with increasing $T$ or $\mu$. We show that the effect of plasminos on $\eta_{f}$ becomes negligible with increasing (decreasing) $T$ ($\mu$)., Comment: V1: 25 pages, 18 figures; V2: 26 pages, 18 figures. Discussions improved, references added. Version accepted for publication in PRD

We consider the one-way ANOVA problem of testing the equality of several normal means when the variances are not assumed to be equal. This is a generalization of the Behrens-Fisher problem, but even in this special case there is no exact test and the actual size of any test depends on the values of the nuisance parameters. Therefore, controlling the actual size of the test is of main concern. In this article, we first consider a test using the concept of generalized p-value. Extensive simulation studies show that the actual size of this test does not exceed the nominal level, for practically all values of the nuisance parameters, but the test is not too conservative either, in the sense that the actual size of the test can be very close to the nominal level for some values of the nuisance parameters. We then use this test to propose a simple F-test, which has similar properties but avoids the computations associated with generalized p-values. Because of its simplicity, both conceptually as well as computa...

This article considers the two-piece normal-Laplace (TPNL) distribution, a split skew distribution consisting of a normal part, and a Laplace part. The distribution is indexed by three parameters, representing location, scale, and shape. As illustrated with several examples, the TPNL family of distributions provides a useful alternative to other families of asymmetric distributions on the real line. However, because the likelihood function is not well behaved, standard theory of maximum-likelihood (ML) estimation does not apply to the TPNL family. In particular, the likelihood function can have multiple local maxima. We provide a procedure for computing ML estimators, and prove consistency and asymptotic normality of ML estimators, using non standard methods.

Correction of a deviated nose is a challenging problem for which different approaches may be considered. This study was designed to introduce a new technique for correction of a deviated nose with a high success rate.The study was a prospective follow-up of 59 patients with deviated nose who had undergone corrective surgery.An extended osteocartilaginous spreader graft was harvested from the quadrangular septum and the perpendicular plate of the ethmoid. After a medial osteotomy that was performed on the concave side, the nasal bone was lateralized and an extended osteocartilaginous spreader graft was inserted between the nasal bone and the septum to prevent further retraction of the concave side due to fibrotic scar tissue. On the contralateral side, a low lateral osteotomy was done as routine.The operation was done on the 59 cases with deviated nose. The subjects were followed up during a period of 8 months to 4 years. According to physical examination, postoperative photography, and patients' satisfaction, the final results were categorized as excellent, fair, or poor.Forty-eight patients (81.3%) were categorized as having excellent results. Eight patients (13.6%) showed fair improvement, while the results of surgery in only 3 patients (5.1%) were classified as poor.An extended osteocartilaginous spreader graft, with medial osteotomy and lateralization of the nasal bone on the concave side, is a new technique with a high success rate for correction of deviated nose.

The advent of Big Data has brought many challenges and opportunities in distributed systems, which have only amplified with the rate of growth of data. There is a need to rethink the software stack for supporting data intensive computing and big data analytics. Over the past decade, the data analytics applications have turned to finer granular tasks which are shorter in duration and much more in quantity. Such applications require new frameworks to handle their data flow. Distributed Message Queues have proven to be essential building blocks in distributed computing towards the support for fine granular workloads. Distributed message queues such as Amazon's SQS or Apache's Kafka have been used in handling massive data volumes, content delivery, and many more. They have also been used in large scale job scheduling on public clouds. However, even these frameworks have some limitations that make them incapable of handling large scale data with high efficiency. Those are not suitable for High Performance Computing (HPC) applications that require lower latency than what is available on the cloud. We propose Fabriq, a distributed message queue that runs on top of a Distributed Hash Table. The design goal of Fabriq is to achieve lower latency and higher efficiency while being able to handle large scales. Moreover, Fabriq is persistent, reliable and consistent. Also, unlike other state-of-the-art systems, Fabriq guarantees exactly once delivery of the messages. The results show that Fabriq was able to achieve high throughput in both small and large messages. At the scale of 128 nodes, Fabriq's throughput was as high as 1.8 Gigabytes/sec for 1 Megabytes messages, and more than 90,000 messages/sec for 50 bytes messages. At the same scale, Fabriq's latency was less than 1 millisecond. Our framework outperforms other state of the art systems including Kafka and SQS in throughput and latency. Furthermore, our experiments show that Fabriq provides a significantly better load balancing than Kafka. The load difference between Fabriq servers was less than 9.5% (compared to the even share), while in Kafka this difference was 100%, meaning that some servers did not receive any messages and remained idle.

Let H(x, y) be a continuous bivariate distribution function with known marginal distribution functions F(x) and G(y). Suppose the values of H are given at several points, H(x i , y i ) = θ i , i = 1, 2,…, n. We first discuss conditions for the existence of a distribution satisfying these conditions, and present a procedure for checking if such a distribution exists. We then consider finding lower and upper bounds for such distributions. These bounds may be used to establish bounds on the values of Spearman's ρ and Kendall's τ. For n = 2, we present necessary and sufficient conditions for existence of such a distribution function and derive best-possible upper and lower bounds for H(x, y). As shown by a counter-example, these bounds need not be proper distribution functions, and we find conditions for these bounds to be (proper) distribution functions. We also present some results for the general case, where the values of H(x, y) are known at more than two points. In view of the simplification in notation,...

Background The management of certain nasal deformities, especially after prior rhinoplasty, may require grafting material. In this study we describe the use of mastoid bone as a viable and low morbidity autologous graft. Methods Mastoid bone was used for nasal augmentation, smoothing dorsal nasal irregularities, or augmentation of radix. Candidates for mastoid bone graft were patients undergoing primary rhinoplasty suffering from low radix or saddle nose deformity and candidates for secondary rhinoplasty suffering from prior overresection of the osteocartilaginous structures. Results Fifty-six patients met the study criteria. Eighteen patients underwent secondary rhinoplasty and suffered from prior overresection of osteocartilaginous structures and 38 patients underwent primary rhinoplasty. Of these, 18 patients had a low radix and 20 patients had a saddle nose deformity. Follow-up was 6–49 months (mean, 23 months). All cases resulted in an augmented straightened nasal dorsum, increased tip projection, and adjusted radix. There were no cases of graft infection. In two cases the graft was displaced requiring revision. The amount of graft absorption even after 2 years follow-up was acceptable. There were no donor site complications. Conclusions The mastoid bone graft provides adequate autologous bone in most cases of primary or revision rhinoplasty. The donor site carries low morbidity and a well camouflaged scar. It is easily accessible especially for the otolaryngologist who is accustomed to operating on the mastoid bone.

We consider the problem of testing normality against the logistic distribution, based on a random sample of observations. Since the two families are separate (non nested), the ratio of maximized likelihoods (RML) statistic does not have the usual asymptotic chi-square distribution. We derive the saddlepoint approximation to the distribution of the RML statistic and show that this approximation is more accurate than the normal and Edgeworth approximations, especially for tail probabilities that are the main values of interest in hypothesis testing. It is also shown that this test is almost identical to the most powerful invariant test.

For testing separate families of hypotheses, the likelihood ratio test does not have the usual asymptotic properties. This paper considers the asymptotic distribution of the ratio of maximized likelihoods (RML) statistic in the special case of testing separate scale or location-scale families of distributions. We derive saddlepoint approximations to the density and tail probabilities of the log of the RML statistic. These approximations are based on the expansion of the log of the RML statistic up to the second order, which is shown not to depend on the location and scale parameters. The resulting approximations are applied in several cases, including normal versus Laplace, normal versus Cauchy, and Weibull versus log-normal. Our results show that the saddlepoint approximations are satisfactory, even for fairly small sample sizes, and are more accurate than normal approximations and Edgeworth approximations, especially for tail probabilities that are the values of main interest in hypothesis testing problems.

For a two-way ANOVA table, with a single observation per cell, the standard approach is to assume that interaction between the two factors is negligible, and to base inferences about the main factors on the model without interaction. But there is no totally satisfactory method for testing if interaction can be ignored. The classical approach is to specify a functional form for the interaction terms, involving a small number of parameters, and then use an appropriate test. But, such tests have low power if the functional form is inappropriate. This has led researchers to propose tests which do not assume a specific form for the interactions. In this article, we present a new approach for testing interaction which also does not assume a specific form for the interaction. This approach is fairly simple and flexible, and its usefulness is illustrated with several examples. We also present a general result which shows that there is no test of interaction with good power properties against all types of interaction.

Motivated by an application in change point analysis, we derive a closed form for the density function of the sum of n independent, non-identically distributed, uniform random variables.

In this paper, we propose and implement a key-value store that supports MPI while allowing application access at any time without having to declaring in the same MPI communication world. This feature may significantly simplify the application design and allow programmers leverage the power of key-value store in an intuitive way. In our preliminary experiment results captured from a supercomputer at Los Alamos National Laboratory, our prototype shows linear scalability at up to 256 nodes.

In the era of big data and cloud, distributed key-value stores are increasingly used as building blocks of large-scale applications. Comparing to traditional relational databases, key-value stores are particularly compelling due to their low latency and excellent scalability. Many big companies, such as Facebook and Amazon, run multiple different applications and services on top of a single key-value store deployment to reduce the deployment and maintenance complexity as well as economic cost. However, every application has its performance requirement but most current key-value store systems are designed to serve every application request equally. This design works well when a single application accesses the key-value store, but it is not as good for the emerging concurrent multi-application scenario. In this paper, we present ZHT/Q, a flexible QoS (Quality of Service) fortified distributed key-value storage system for clouds and data centers. It improves the overall throughput by an order of magnitude and still satisfies different applications' latency requirements with QoS using dynamic and adaptive request batching mechanisms. The experiment results show that our new system delivers up to 28 times higher throughput than the base solution while more than 99% of requests' latency requirements are satisfied.

The emerging applications in big data and social networks issue rapidly increasing demands on graph processing. Graph query operations that involve a large number of vertices and edges can be tremendously slow on traditional databases. The state-of-the-art graph processing systems and databases usually adopt master/slave architecture that potentially impairs their The contributions of this paper are as follows: scalability. This work describes the design and implementation of a new graph processing system based on Bulk Synchronous Parallel model. Our system is built on top of ZHT, a scalable distributed key-value store, which benefits the graph processing in terms of scalability, performance and persistency. The experiment results imply excellent scalability.

Although cloud computing has become one of the most popular paradigms for executing data-intensive applications (for example, Hadoop), the storage subsystem is not optimized for scientific applications. We believe that when executing scientific applications in the cloud, a node-local distributed storage architecture is a key approach to overcome the challenges from the conventional shared/parallel storage systems. We analyze and evaluate four representative file systems (S3FS, HDFS, Ceph, and FusionFS) on three platforms (Kodiak cluster, Amazon EC2 and FermiCloud) with a variety of benchmarks to explore how well these storage systems can handle metadata intensive, write intensive, and read intensive workloads.

k = thermal conductivity of the medium, W/m-K M = number of increments in the X direction N = conduction-radiation parameter, k/4σ T 4 i D n = refractive index of the medium Q = incidence radiation, W/m2 q1, q2 = radiosity from the interior of the two boundaries, W/m2 q1, q2 = dimensionless radiosities, q1/σ T 4 i , q2/σ T 4 i R = dimensionless gradient of radiative heat flux S = source function T = absolute temperature, K Te = temperature of the surroundings, K Ti = initial temperature, K Tm = mean temperature, K t = dimensionless temperature, T/Ti tm = dimensionless mean temperature, Tm/Ti t∗ = temperature from the previous iteration X = dimensionless coordinate, x/D x = coordinate in direction across the layer, m

ARLEN is a heat-resistant, modified polyamide with a high melting point and a rigidity level comparable to super engineering plastics. It possesses strong dimensional stability and is widely used in engineering and high-temperature applications. At elevated temperatures, radiative transfer becomes important, and transient temperature responses, including radiation, can be significantly different from those by conduction alone. This work considers transient radiative and conductive heat transfer in a plane, absorbing, emitting and isotropically scattering layer of ARLEN. The solution includes the radiative two-flux equation, which is coupled with the transient energy equation, and both equations are solved simultaneously. The two-flux method is used as a simplification for obtaining the radiative heat source term in the energy equation. The external boundaries of the layer are exposed to a radiative environment and can be convectively heated or cooled.

A model is presented for the calculation of transient combined radiative and conductive heat transfer in a semitransparent layer of advanced fiber polymer. This model is based on optical material properties. Different boundary conditions were examined. Each side of the layer was exposed to hot or cold radiative surroundings, whereas each boundary was heated or cooled by convection. Emission within the layer and internal reflections depended on the layer refractive index. The reflected energy and heat conduction distributed energy across the layer and partially equalized the transient temperature distributions. The numerical method is an implicit finite difference procedure with nonuniform space and time increments that has been expanded to include external convection and incident radiation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:4181–4189, 2006

Transient radiative and conductive heat transfer in a translucent medium with isotropic optical properties is investigated. The radiative two-flux equation is coupled with the transient energy equation and both equations are solved simultaneously. Transient solutions are obtained for a plane layer with refractive index equal to or larger than one, and with external convection and radiation at each boundary. Illustrative results obtained with the two-flux method show the effects of changing parameters such as optical thicknesses, refractive index, conduction–radiation parameter, and scattering on the transient temperature distribution within the layer. Results are given at different instances during the transient, and the distribution for the largest time is at or very close to steady state. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2277–2283, 2006

A method is developed for obtaining transient temperature distribution in a cooling semitransparent layer of ceramic. The layer is emitting, absorbing, isotropically scattering and heat conducting with a refractive index ranging from 1 to 2. The solution involves solving simultaneously the energy equation and the integral equation for the radiative flux gradient. The energy equation is solved using an implicit finite volume scheme and the integral equation of radiative heat transfer is solved using the singularity technique and Gaussian integration. The effects of scattering are investigated. It is shown that scattering has a significant effect on the transient temperature distribution and the transient mean temperature of the layer.

An analysis is developed for computing transient thermal behavior in a layer of polyamide 6T. The radiative two-flux equation is coupled with the transient energy equation, and for the general boundary conditions of external convection and radiation on the layer with diffuse interfaces, it is shown that the two-flux method can be used to predict accurate steady-state temperature distributions. The layer refractive indices are larger than one and internal reflections are included. The analysis includes internal emission, absorption, and isotropic scattering and heat conduction. An advantage of the two-flux method is that isotropic scattering is included without any additional complication and some transient results with large scattering are given to illustrate scattering effects.

This work considers transient radiative and conductive heat transfer in a semitransparent layer of ceramic, submitted to several thermal and radiative boundary conditions. Each side of the layer is exposed to hot or cold radiative surroundings, while each boundary is heated or cooled by convection. The solution procedure must provide accurate temperature distribution in the layer, so a nodal analysis based on Hottel's zonal method extended by ray tracing method is carried out. A finite difference method with non-uniform space and time increments is used to solve the transient energy equation, including a radiative heat source, coupled to a equation of radiative transfer. Variable spacing was used to concentrate grid points in regions with large temperature gradients. The influence of refractive index, optical thicknesses and conduction–radiation parameters is investigated.

By the addition of metal and oxide particles to plastics, thermal transport properties, heat capacity, and density of polymers can be varied systematically. Radiation effects in a particle filled with various fillet become more important and transient temperature responses including radiation can be significantly different from those by conduction alone. Transient combined conduction-radiation heat transfer Is analyzed in a non-gray layer of plastics, submitted to several thermal and radiative boundary conditions. The numerical method is an implicit finite difference procedure with nonuniform space and time increments. Coupling problems for the prescribed temperatures, prescribed radiative-conductive heat exchange laws, and mixed kind thermal boundary conditions are worked out for opaque as well as vitreous interlaces with specular inflections. Solutions are given to demonstrate the effect of different parameters, such as radiation-conduction parameter, rediation-convection parameter, and emissivity of the surfaces on temperature distribution and heat flux profiles across the layer.

The behavior of a heat-conducting, absorbing, and emitting layer of ceramic is considered, during transient combined conductive–radiative heat transfer. The solution includes the equation of radiative transfer within the material coupled to a transient energy equation that contains both radiative and conductive terms. It is based on nodal analysis and Hottel's zonal method extended by the ray tracing method. The transient energy equation including a radiative internal energy source is solved using a time marching finite difference procedure with variable space and time increments. The effects of the influence parameters, optical thicknesses, and refractive index of the layer are considered carefully.

A numerical solution is carried out to treat the transient cooling problem with conduction and radiation for a hot spherical body covered with a cold coating material. The solution includes the equations of radiative transfer, coupled with a transient energy equation that contains both radiative and conductive terms. The radiative transfer equation was solved by the discrete ordinates method, and a parmetric study was performed by changing various physical parameters such as the optical thicknesses, thermal conductivity of the coating, emissivity, and diffusivity of the sphere. It was found that the properties of the coating have a direct effect on the cooling rate of the sphere.

The noncommutative dipole QED is studied in detail for the matter fields in the adjoint representation. The axial anomaly of this theory is calculated in two and four dimensions using various regularization methods. The Ward-Takahashi identity is proved by making use of a non-perturbative path integral method. The one-loop $\beta$-function of the theory is calculated explicitly. It turns out that the value of the $\beta$-function depends on the direction of the dipole length $\vec{L}$, which defines the noncommutativity. Finally using a semi-classical approximation a non-perturbative definition of the form factors is presented and the anomalous magnetic moment of this theory at one-loop order is computed., Comment: 1+30 pages, LaTeX, axodraw.sty, 7 figures

Task scheduling and execution over large scale, distributed systems plays an important role on achieving good performance and high system utilization. Due to the explosion of parallelism found in today's hardware, applications need to perform over-decomposition to deliver good performance; this over-decomposition is driving job management systems' requirements to support applications with a growing number of tasks with finer granularity. Our goal in this work is to provide a compact, light-weight, scalable, and distributed task execution framework (CloudKon) that builds upon cloud computing building blocks (Amazon EC2, SQS, and DynamoDB). Most of today's state-of-the-art job execution systems have predominantly Master/Slaves architectures, which have inherent limitations, such as scalability issues at extreme scales and single point of failures. On the other hand distributed job management systems are complex, and employ non-trivial load balancing algorithms to maintain good utilization. CloudKon is a distributed job management system that can support both HPC and MTC workloads with millions of tasks/jobs. We compare our work with other state-of-the-art job management systems including Sparrow and MATRIX. The results show that CloudKon delivers better scalability compared to other state-of-the-art systems for some metrics - all with a significantly smaller code-base (5%).

In today's world, distributed message queues are used in many systems and play different roles (e.g. content delivery, notification system and message delivery tools). It is important for the queue services to be able to deliver messages at large scales with a variety of message sizes with high concurrency. An example of a commercial state of the art distributed message queue is Amazon Simple Queuing Service (SQS). SQS is a distributed message delivery fabric that is highly scalable. It can queue unlimited number of short messages (maximum size: 256 KB) and deliver them to multiple users in parallel. In order to be able to provide such high throughput at large scales, SQS omits some of features that are provided by traditional queues. SQS does not guarantee the order of the messages, nor does it guarantee the exactly once delivery. This paper addresses these limitations through the design and implementation of HDMQ, a hierarchical distributed message queue. HDMQ consist of collection of area message nodes that can be used to store messages up to 512 KB. It utilizes a round robin local load balancer to save the message and scale across the area region accordingly. HDMQ provides replication for high reliability of messages. It also provides SQS-like APIs in order to provide compatibility with current systems that currently use SQS. We performed a detailed performance evaluation and compared HDMQ to the commonly used commercial distributed queues measuring throughput, latency and price per request. We found HDMQ to outperform SQS, Windows Azure Service bus, and IronMQ by up to 2--15x times in throughput, 1.6--39x times in latency, and all this for 13%-80% less costs.

The effect of anomalous magnetic moment of quarks on thermodynamic properties of the chiral condensate is studied, using of a two-flavor Nambu--Jona-Lasinio model at finite temperature $T$, chemical potential $\mu$, and in the presence of a uniform magnetic field $eB$. To this purpose, the Schwinger linear-in-$B$ ansatz for the quark anomalous magnetic moment in term of the nonperturbative Bohr magneton is considered. In a two-dimensional flavor space, it leads to the correction $\hat{T}_{Sch}=\hat{\kappa}\hat{Q} eB$ in the energy dispersion relation of quarks. Here, $\hat{Q}$ is the quark charge matrix. We consider three different sets for $\hat{\kappa}$, and numerically determine the dependence of the constituent quark mass on $T,\mu$ and $eB$ for fixed $\hat{\kappa}$. By exploring the complete phase portrait of this model in $T$-$\mu$, $\mu$-$eB$, and $T$-$eB$ phase spaces for various fixed $eB$, $T$, $\mu$ and $\hat{\kappa}$, we observe that inverse magnetic catalysis occurs for large enough $\hat{\kappa}$. Moreover, in the regime of weak magnetic fields, the phenomenon of reentrance of chiral symmetry broken and restored phases occurs for $T, \mu$ and $eB$ dependent $\hat{\kappa}$., Comment: 22 pages, 14 figures

Steam reforming of methane in a packed bed reactor filled with Nickel based catalyst supported on Alumina, (Al2O3) is theoretically and experimentally studied and analyzed. State of the art Finite Element Method software, COMSOL Multiphysics is used to simulate a steady state two dimensional heterogeneous model, coupled with detailed reaction mechanisms modeling surface and gas-phase kinetics that takes into account the diffusion reaction phenomena inside the particles. The simulation results are compared favorably with experimental data. It is shown that strong axial and radial temperature gradients exist near the reactor wall The obtained results are important in design and optimizing of commercial reactors.Copyright © 2013 by ASME

The directional weak decay constants of neutral pions are determined at finite temperature T, chemical potential \mu and in the presence of a constant magnetic field B. To do this, we first derive the energy dispersion relation of neutral pions from the corresponding effective action of a two-flavor, hot and magnetized Nambu--Jona-Lasinio model. Using this dispersion relation, including nontrivial directional refraction indices, we then generalize the PCAC relation of neutral pions and derive the Goldberger-Treiman (GT) as well as the Gell--Mann-Oakes-Renner (GOR) relations consisting of directional quark-pion coupling constant g_{qq\pi^{0}}^{(\mu)} and weak decay constant f_{\pi^{0}}^{(\mu)} of neutral pions. The temperature dependence of g_{qq\pi^{0}}^{(\mu)} and f_{\pi^{0}}^{(\mu)}, are then determined for fixed chemical potential and various constant background magnetic fields. The GT and GOR relations are also verified at finite T,\mu and eB. It is shown that, because of the explicit breaking of the Lorentz invariance by the magnetic field, the directional quark-pion coupling and decay constants of neutral pions in the longitudinal and transverse directions with respect to the direction of the external magnetic field are different, i.e. g_{qq\pi^{0}}^{\|}\neq g_{qq\pi^{0}}^{\perp} and f_{\pi^{0}}^{\|}\neq f_{\pi^{0}}^{\perp}. As it turns out, for fixed T,\mu and B, g_{qq\pi^{0}}^{\|}> g_{qq\pi^{0}}^{\perp} and f_{\pi^{0}}^{\|}< f_{\pi^{0}}^{\perp}., Comment: V1: 25 pages, 15 figures; V2: 27 pages, 15 figures, 1 table. Discussions improved, references updated. Version accepted for publication in PRD

Utilizing an extended two-flavor Nambu-Jona Lasinio (NJL) m odel, we review some of the effects of external magnetic fields on two-flavor color superconduct ing phase (2SC) at moderate baryon densities in the QCD phase diagram. The effective action of the extended NJL model consists of two mass gaps as functions of three intensive quantities, the temperature, the quark chemical potential and the external magnetic field. The nonzero value s of the mass gaps, chiral and diquark condensates, induce spontaneous chiral and color symmetry breaking, respectively, and as a result two different phases of quark matter appear. We find the trans ition curves between these phases as well as the critical points in the QCD phase diagram in terms of the intensive quantities. Imposing a constant strong magnetic field on these two phases, we show t hat the mass gaps increase with the magnetic field and the symmetry breaking region in the QCD phase diagram expands even to the larger values of temperature and quark chemical potential. This phenomenon is a consequence of the magnetic catalysis of dynamical symmetry breaking, which is proven before.

Hydrogen and synthesis gas are the most important energy carriers in the sustainable energy supply system of the future and play a key role in production of many chemical and petrochemicals in oil and energy industries. Steam reforming of light hydrocarbons, like methane, ethylene and propylene, produced from biomass gasification, is proven to have many advantages and environmental benefits. It is an efficient and economical option in industry and the most common process for hydrogen production. Steam reforming process converts light hydrocarbons from biomass into hydrogen and carbon monoxide at high temperatures in the presence of a nickel or noble metal based catalysts. The process uses fixed bed reactors, filled with catalyst particles in order to increase the reactive surface area between the flow phases and improve the efficiency of the reactions. Due to the strongly endothermic nature of the process, a large amount of heat is supplied to the reactor and therefore the tube wall and the catalyst particles are exposed to significant axial and radial temperature gradients. In developing such reactors, the knowledge of the temperature profile within the reactor is important for designing and optimizing the catalysts structure and the reactor geometry to achieve the best performance. However, due to insufficient room for a thermocouple or to potential interference with local fluid dynamics, temperature measurement within the reactor becomes difficult. Therefore, to evaluate not only the local temperature profiles but the whole reactor performance in terms of conversion and selectivity, accurate descriptive and predictive models are necessary. A steady state experimental and theoretical model is developed to investigate the performance of the catalytic steam reforming tubular reactor. A packed bed reactor consisting of cylindrical catalyst particles is simulated numerically to investigate the reforming chemistry and evaluate the diffusional resistances. The mathematical modeling and solutions consist of both pseudo-heterogeneous model and a pseudo-homogeneous model. Pseudo-homogeneous reactor models do not distinguish between the gas and solid phases in the fixed bed reactor. Averaged properties are used and the temperature, pressure and concentrations are equal inside the catalyst and in the gas phase. Heterogeneous models distinguish between the fluid phase and the solid phase to correctly account for the heat transfer in the reactor. Reaction kinetics, reaction rates, effectiveness factors and partial differential equations including mass transfer and energy balance equations are studied in detail. This thesis includes the extensive review of the already published research papers in this field to find empirically correlations for packed bed reactors, suitable for different cases. Wide varieties of correlations are used to calculate effectiveness factors, dispersion and diffusion coefficients according to the type and shape of the catalysts. Hydrogen sulfide is known to deactivate nickel based steam reforming catalysts by chemisorptions on the metal surface. The metal sulfur bond is so strong and even at extremely low gas phase concentrations of hydrogen sulfide the catalytic activity is substantially reduced. Using conventional sulfur cleaning has a negative effect on process efficiency and steam reforming has to be run without cleaning the gas prior to the reactor. This thesis aim is to describe and model sulfur deactivation effects and steam reforming process in a combined kinetic equation. All chemical reactions are mathematically solved and modeled by the state of the art, COMSOL Multiphysics 4.3 software, which represents a powerful and general class of finite element methods and techniques for approximate solution of partial differential equations. Choosing similar operating conditions in terms of inlet composition and temperature as in experiments allows a direct comparison between experimental and modeling results to validate and see how well the simulation predicts the experimental results. The result of the modeling shows temperature and pressure distribution, and gas composition along the reactor and predicts accurate results when the inlet and process conditions are changed. They are also able to find the optimum characteristics and geometry dimensions for a steam reformer used for a specific process. The effect of varying operating parameters like steam to carbon molar ratio, temperature, gas composition, space velocity, different amount of sulfur on the hydrocarbon conversion, hydrogen yield and reforming efficiency are investigated carefully.