bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Finite Element Analysis of Temperature Profiles and Cooling Rates of ERW Pipes during TIG Welding
Authors: Bhattacharya Tathagata , Bandyopadhyay Asish , Pal Pradip Kumar 
Published: March 2014

AbstractThe present investigation deals with the determination of temperature profile and subsequent cooling rates of certain points on the external surface of an ERW pipe with the help of ANSYS Finite Element Modeling and Analysis method, under simulated TIG welding conditions. A TIG welding condition for an ERW pipe is first simulated through ANSYS Finite Element Modeling. The physical and material properties along with the dimensions and size of the ERW pipe are all included in the modeling part. The TIG welding arc is simulated as a point heat source of a given power traversing the periphery of the pipe surface during welding. In the ANSYS program, after modeling the TIG welding problem, the same is run in the post – processing analysis part to get the temperature profile along the external surface of the pipe at various time intervals from the start of the welding. The rate of cooling of a few particular nodes on the modeled pipe surface, from the start of welding to the completion of one welding pass is also studied and results are indicated in graphical form. Later, these cooling rates on the modeled pipe surface are compared with those of an exactly similar ERW pipe, physically welded by TIG welding method in the workshop under similar welding conditions and welding parameters.
TALENs Mediate Efficient and Heritable Mutation of Endogenous Genes in the Marine Annelid Platynereis dumerilii
Authors: Bannister Stephanie , Antonova Olga , Polo Alessandra , Lohs Claudia , Hallay Natalia , Valinciute Agne , Raible Florian , Tessmar-Raible Kristin 
Published: March 2014

Abstract
Platynereis dumerilii is a marine polychaete and an established model system for studies of evolution and development. Platynereis is also a re-emerging model for studying the molecular basis of circalunar reproductive timing: a biological phenomenon observed in many marine species. While gene expression studies have provided new insight into patterns of gene regulation, a lack of reverse genetic tools has so far limited the depth of functional analyses in this species. To address this need, we established customized transcriptional activator-like effector nucleases (TALENs) as a tool to engineer targeted modifications in Platynereis genes. By adapting a workflow of TALEN construction protocols and mutation screening approaches for use in Platynereis, we engineered frameshift mutations in three endogenous Platynereis genes. We confirmed that such mutations are heritable, demonstrating that TALENs can be used to generate homozygous knockout lines in P. dumerilii. This is the first use of TALENs for generating genetic knockout mutations in an annelid model. These tools not only open the door for detailed in vivo functional analyses, but also can facilitate further technical development, such as targeted genome editing.
Evidence for Local Regulatory Control of Escape from Imprinted X Chromosome Inactivation
Authors: Mugford Joshua W , Starmer Joshua , Williams Rex L , Calabrese J Mauro , Mieczkowski Piotr , Yee Della , Magnuson Terry 
Published: March 2014

AbstractX chromosome inactivation (XCI) is an epigenetic process that almost completely inactivates one of two X chromosomes in somatic cells of mammalian females. A few genes are known to escape XCI and the mechanism for this escape remains unclear. Here, using mouse trophoblast stem (TS) cells, we address whether particular chromosomal interactions facilitate escape from imprinted XCI. We demonstrate that promoters of genes escaping XCI do not congregate to any particular region of the genome in TS cells. Further, the escape status of a gene was uncorrelated with the types of genomic features and gene activity located in contacted regions. Our results suggest that genes escaping imprinted XCI do so by using the same regulatory sequences as their expressed alleles on the active X chromosome. We suggest a model where regulatory control of escape from imprinted XCI is mediated by genomic elements located in close linear proximity to escaping genes.
Optical and electrical study of cap layer effect in QHE devices with double-2DEG
Authors: Zamora-Peredo L. , Cortes-Mestizo I. , García-Gonzáez L. , Hernández-Torres J. , Hernandez-Quiroz T. , Peres-Caro M. , Ramirez-López M. , Martinez-Veliz I. , Casallas-Moreno Y. L. , Gallardo-Hernández S. , Conde-Gallardo A. , López-López M. 
Published: March 2014

ABSTRACTIn this work we report on the characteristics of GaAs/AlGaAs heterostructures with a symmetric double two-dimensional electron gas (D-2DEG). Optical characterization was made by room temperature photoreflectance (PR) spectroscopy as well as electrical properties were determinated using the quantum Hall effect measurements at 2K. In order to study the surface effects on the conduction band profile, three samples with different GaAs cap layer thickness (25, 60 and 80 nm) were grown by the molecular beam epitaxy. Photoreflectance spectra at room temperature show the wide-period Franz-Keldysh oscillations between 1.42 and 1.70 eV originated by the surface electric field. The analysis of these oscillations shows that the surface electric field varies from 503 to 120 kV/cm whereas the thickness of the cap layer increases that was produced by the reduction of the depletion zone near the surface. Using QHE measurements we found that electron density increases if the surface electric field decreases.
Focused Ion Beam (FIB) Milling and Automotive Catalysis Aging: A Novel Approach for the Direct Observation of Interfacial and Sub-Surface Chemical and Structural Properties Relevant to Catalyst Aging and Functionality
Authors: Kamp Carl J. , Sappok Alexander G. , Wong Victor W. 
Published: March 2014

ABSTRACTThe combined focused ion beam/scanning electron microscopy/energy dispersive X-ray spectroscopy (FIB/SEM/EDX) system is a novel tool for the automotive catalysis field. Automotive emissions such as SOx, NOx, and particulate matter (PM) are regulated to various extents throughout the world, requiring the use of multiple aftertreatment components such as the diesel particulate filter (DPF), diesel oxidation catalyst (DOC), three-way catalytic converter (TWC), Lean NOx trap (LNT) and selective catalytic reduction (SCR). While these aforementioned aftertreatment components are generally multifunctional and robust in design, thermal and chemical aging over the components’ useful lifetimes results in significantly degraded performance leading to increased engine emissions levels and decreased fuel economy. While the component sizes themselves are generally large (10s of cm to ≈1/2 m), component aging mechanisms usually dominate on the nm-µm scales. In particular, this study has used the FIB/SEM/EDX system to investigate the aging of the diesel particulate filter (DPF) due to engine lubricant-derived inorganic ash accumulation. The FIB/SEM/EDX system has been used in the automotive aftertreatment field for the first time with many surprising and significant findings. Although the samples used in this study are quite different to those typically found in FIB studies, the authors have shown that the FIB/SEM/EDX system is a valuable tool in this research area, especially for the investigation of µm-size intra-particle structure and nm-µm interfacial/sub-surface details around the aged catalyst surface.
Novel Methods of Nanoscale Wire Formation
Authors: Prokes S.M. , Wang Kang L. 
Published: March 2014

In recent years, tremendous interest has been generated in the fabrication and characterization of nanoscale structures such as quantum dots and wires. For example, there is interest in the electronic, magnetic, mechanical, and chemical properties of materials with reduced dimensions. In the case of nanoscale semiconductors, quantum effects are expected to play an increasingly prominent role in the physics of nanostructures, and a new class of electronic and optoelectronic devices may be possible. In addition to new and interesting physics, the formation and characterization of nanoscale magnetic structures could result in higher-density storage capacity in hard disks and optical-recording media. Likewise, phonon confinement leads to a drastic reduction of thermal conductivity and can be used to improve the performance of thermoelectric devices.In 1980, H. Sakaki predicted theoretically that quantum wires may have applications in high-performance transport devices, due to their sawtoothlike density of states (E1/2), where E is the electron energy. Since then, most quantum wires have been made by fabricating a gratinglike gate on top of a two-dimensional (2D) electron gas contained in a semiconductor heterojunction or in metal-oxide-semiconductor structures. By applying a negative gate voltage to the system, its structure can be changed from a 2D to a one-dimensional (1D) regime, where electron confinement is achieved by an electrostatic confining potential. It was not until recently that “physical” semiconductor quantum wires with the demonstrated 1D confinement by physical boundaries began to be fabricated.
Bulk Glass-Forming Metallic Alloys: Science and Technology
Authors: Johnson William L. 
Published: March 2014

The following article is based on the MRS Medal talk presented by William L. Johnson at the 1998 MRS Fall Meeting on December 2, 1998. The MRS Medal is awarded for a specific outstanding recent discovery or advancement that has a major impact on the progress of a materials-related field. Johnson received the honor for his development of bulk metallic glass-forming alloys, the fundamental understanding of the thermodynamics and kinetics that control glass formation and crystallization of glass-forming liquids, and the application of these materials in engineering.The development of bulk glass-forming metallic alloys has led to interesting advances in the science of liquid metals. This article begins with brief remarks about the history and background of the field, then follows with a discussion of multicomponent glass-forming alloys and deep eutectics, the chemical constitution of these new alloys, and how they differ from metallic glasses of a decade ago or earlier. Recent studies of deeply undercooled liquid alloys and the insights made possible by their exceptional stability with respect to crystallization will then be discussed. Advances in this area will be illustrated by several examples. The article then describes some of the physical and specific mechanical properties of bulk metallic glasses (BMGs), and concludes with some interesting potential applications.The first liquid-metal alloy vitrified by cooling from the molten state to the glass transition was Au-Si, as reported by Duwez at Caltech in 1960. Duwez made this discovery as a result of developing rapid quenching techniques for chilling metallic liquids at very high rates of 105–106 K/s.
Small Cracks and the Transition to Long Cracks
Authors: Morris W.L. , James M.R. 
Published: March 2014

The propagation of small fatigue cracks differs considerably from that of long cracks in the same material. Small cracks tend to grow more rapidly than would be expected from long-crack data. Following Suresh and Ritchie, cracks are small when (1) their length is small compared to the scale of local plasticity (a linear elastic fracture mechanics, LEFM, limitation); (2) their length is small compared to microstructural dimensions (a continuum mechanics limitation); or (3) they are merely physically small. The importance of understanding the anomalously rapid growth of small cracks has been the subject of recent reviews and two specialized conferences. The impact of small cracks on component design is to force the design of highly conservative structures.Many investigators have tried to correct LEFM to account for crack shortness. Since the early work of Kitagawa and Takahashi and Smith showing the limitations of LEFM, many procedures to modify, correct, or replace LEFM have been proposed to predict short-crack growth rates. These include mechanisms based on crack closure stress and crack deflection, elastic-plastic approaches such as theJintegral, or simply semi-empirical approaches. These methods have been reasonably successful when the crack length is a few times that of the relevant micro-structural size.
Environmental Effects on the Cracking of Engineering Materials
Authors: Kasul David B. , Heldt Lloyd A. 
Published: March 2014

A material's susceptibility to cracking may be significantly affected by its chemical environment. Stress corrosion cracking (SCC), liquid metal embrittle-ment (LME), hydrogen embrittlement (HE), and corrosion fatigue are examples of environmental effects which cause ductility or endurance losses through environment-assisted cracking (EAC). Under certain conditions, virtually all commercially important materials are susceptible to one or more of the above embrittlement processes. Cracking may occur intergranularly, transgranularly, or in a mixed mode, depending on conditions. Much is known about the metallurgical and environmental conditions which promote environment-assisted cracking, and prudent control of these is often successful in mitigating or preventing cracking. However, in spite of our understanding of the factors controlling SCC, LME, and HE, the responsible mechanisms remain elusive.This article will (1) review some of the important variables affecting these phenomena, such as stress, stress intensity, material microstructure, strain rate, electrochemical potential and pH, and (2) attempt to relate phenomeno-logical characteristics of environment-induced embrittlement to several mechanisms proposed for environment-assisted cracking, as they are understood today.The problem of stress corrosion cracking is unquestionably the most costly of environmental cracking phenomena, with losses occurring in a wide variety of service environments. Liquid metal embrittlement is of concern in nuclear power and other industries. Hydrogen embrittlement, first recognized as an embrittler of iron in 1873, causes cracking problems in applications ranging from welding to oil drilling. In all, the list of situations in which environment-assisted cracking occurs is long and is likely to grow as materials are increasingly challenged by the severity of their service conditions.
Recent Advances in Understanding Helium Embrittlement in Metals
Authors: Baskes M.I. 
Published: March 2014

Helium is formed in metals as a secondary product of fission/fusion energy technology. Even though helium is chemically inert and essentially insoluble in metals, under specific exposure conditions it is known to cause them to lose their ductility. At high temperatures, helium atoms produced from the transmutation of 10B or from a two-step process with 58Ni in amounts as low as a few parts per million migrate to grain boundaries to cause inter-granular failure. Ion implantation of helium may cause a similar effect. More recently it has been found that helium produced from tritium decay at or slightly above room temperature also markedly degrades the mechanical properties of metals. In order to design alloys of the future it is necessary to understand the mechanisms responsible for this helium embrittlement.Early experiments found that helium is strongly trapped at radiation-produced defects in metals. Atomistic calculations using pair potential interactions verified these findings. It was initially thought that the helium embrittlement in metals was due to the trapping and subsequent bubble formation at radiation-induced defects. It has been shown, however, that helium may be trapped in metals even in the absence of radiation damage. Thomas et al. found that 3He generated at low temperatures from tritium decay remained trapped in nickel upon heating to 500°C. In both this experimentand a subsequentone in gold the helium was introduced without the production of radiation damage. In this second experiment Thomas used transmission electron microscopy to see in the gold small (10Å) bubbles that had been implanted with low-energy (sub-damage threshold) helium.
The Effect of Concomitant Cardiac Resynchronization Therapy on Quality of Life in Patients with Heart Failure Undergoing Cardiac Surgery
Authors: Thorén Emma , Kesek Milos , Jidéus Lena 
Published: March 2014

Objectives:
To evaluate the effect of concomitant cardiac resynchronization therapy (CRT) on health related quality of life (QoL) in patients with heart failure (HF) and ventricular dyssynchrony undergoing cardiac surgery.

Methods:
Twenty-eight patients received permanent epicardial CRT in connection to coronary artery bypass grafting (CABG) and/or aortic valve replacement (AVR) (CRT group). Thirty-seven HF patients without concomitant CRT served as a comparison group (non-CRT group). SF-36 was used to assess QoL in the two groups and was also compared with the general Swedish population.

Results:
The median follow-up time was 28 months after surgery (range 8 to 44 months). No difference in QoL could be shown between the CRT group and the comparison group. Several subscales of QoL in the CRT group were in range with the general Swedish population.

Conclusion:
Concomitant CRT for patients with HF and ventricular dyssynchrony undergoing CABG and/or AVR did not result in a higher estimated QoL compared to HF patients without CRT.
Chaos synchronization of a fractional nonautonomous system
Authors: Hammouch Zakia , Mekkaoui Toufik 
Published: March 2014

AbstractIn this paper we investigate the dynamic behavior of a nonautonomous fractional-order biological system.With the stability criterion of active nonlinear fractional systems, the synchronization of the studied chaotic system is obtained. On the other hand, using a Phase-Locked-Loop (PLL) analogy we synchronize the same system. The numerical results demonstrate the efiectiveness of the proposed methods
Panentheism in the context of the theology and science dialogue
Authors: Bracken Joseph A. 
Published: March 2014

AbstractThe term “panentheism” (literally, everything in God) mediates between pantheism of the sort espoused by Spinoza and classical theism (God as transcendent Creator of the world). In this essay, in dialogue with the contemporary Danish theologian Niels Henrik Gregersen I review various historical positions re panentheism before concluding with a summary statement of my own understanding of the God-world relationship. The ancient Greek Orthodox tradition, for example, can be retrieved to set forth what might be called soteriological panentheism whereby the communitarian life of the three divine persons of the Christian doctrine of the Trinity is freely offered to all creatures at the end of the world. The German Idealists Krause, Hegel and Schelling focused instead on the progressive self-manifestation of God in the world of creation in and through a dialectical process governed by Divine Mind or Will. In the mid-20th century Charles Hartshorne, the disciple of Alfred North Whitehead, presented what he called dipolar panentheism: God as the “soul” of the world and the world as the “body of God.” The Jesuit paleontologist Pierre Teilhard de Chardin located the goal of cosmic evolution in the Pauline vision of the Cosmic Christ who thereby “personalizes” the whole of creation. Most current understandings of panentheism are derived from one or another of these earlier efforts at understanding how the world can be both in God and yet distinct from God. I myself use the notion of hierarchically ordered systems employed in the life-sciences to make clear how the higher-order system proper to the communitarian life of the three divine persons both conditions and is conditioned by the lower-order systems proper to the world of creation.
On a problem of Bertram Yood
Authors: Abel Mart , Abel Mati 
Published: March 2014

Abstract
In 1964, Bertram Yood posed the following problem: whether the intersection of all closed maximal regular left ideals of a topological ring coincides with the intersection of all closed maximal regular right ideals of this ring. It is proved that these two intersections coincide for advertive and simplicial topological rings and, using this result, it is shown that the topological left radical and the topological right radical for every advertive and simplicial topological algebra coincide.
Objectively Measured Sedentary Time in Youth With Cerebral Palsy Compared With Age-, Sex-, and Season-Matched Youth Who Are Developing Typically: An Explorative Study
Authors: Obeid Joyce , Balemans Astrid C.J. , Noorduyn Stephen G. , Gorter Jan Willem , Timmons Brian W. 
Published: March 2014

Background
Children with cerebral palsy (CP) demonstrate reduced physical activity levels compared with children with typical development. Sedentary behavior, including the duration and frequency of sedentary bouts, has not yet been objectively examined in this population but may have clinical implications for the development of secondary health complications.

Objective
The aim of this study was to identify time spent sedentary and frequency of breaks interrupting sedentary time in youth with CP compared with youth without CP. It was hypothesized that individuals with CP would spend more hours sedentary than their peers and take fewer breaks to interrupt sedentary time.

Design
This was a cross-sectional, prospective study.

Methods
A convenience sample of 17 ambulatory children with CP (15 boys and 2 girls) (mean age=13.0 years, SD=2.2) and 17 age-, sex-, and season-matched youth who were developing typically (TD group) (mean age=12.9 years, SD=2.5) wore an accelerometer over a 7-day period. Sedentary time (in minutes) and number of breaks from sedentary time, corrected for monitoring and sedentary time, respectively, were examined. Differences between groups were determined with an independent-samples t test.

Results
Children with CP engaged in significantly more sedentary time (X̅=47.5 min/h, SD=4.9) compared with the TD group (X̅=43.6 min/h, SD=4.2), with significantly fewer breaks from sedentary time (CP group: X̅=179, SD=70; TD group: X̅=232 breaks/h sedentary, SD=61).

Limitations
The sample included only ambulatory youth with CP, classified as Gross Motor Function Classification System levels I to III.

Conclusions
Sedentary time was higher in the CP group and was characterized by less frequent breaks compared with the TD group. Future research should examine the extent to which sedentary time is associated with cardiovascular and metabolic risk in youth with CP.
Calculating balance velocities with a membrane stress correction
Authors: Williams C. Rosie , Hindmarsh Richard C.A. , Arthern Robert J. 
Published: March 2014

AbstractInverse methods, where surface data are ‘inverted’ in order to quantify basal properties of ice sheets, play a major role in initializations. The balance-velocity method is a unique linear initialization, in which accumulation, surface elevation and thickness data are used to calculate the velocities and basal conditions required to maintain the observed ice-sheet altimetric signal, resulting in an estimate of the basal sliding viscosity that is guaranteed to be non-negative. We examine the observation that balance velocities based on the shallow-ice approximation (SIA) are extremely dependent on grid size, showing that Antarctic balance velocities on a 1 km grid are excessively over-channelized. Incorporating the membrane-stress approximation into balance-velocity calculations and comparing them with a simplified analytical solution shows that numerical error monotonically decreases with grid resolution and over-channelization is eliminated for Newtonian and non-Newtonian rheology. In contrast, for the SIA reducing grid size below the membrane-stress coupling length fails to improve accuracy. However, since this approach is nonlinear, a unique viscosity solution is not guaranteed, and in practice ‘sliding viscosity’ estimates are noisy. This raises problems of the sensitivity of these estimates to data and model errors, which may mean using inverse or smoothing techniques in association with balance-velocity methods in many, if not all, practical applications.