bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sleep inertia, sleep homeostatic and circadian influences on higher‐order cognitive functions
Authors: Burke Tina M. , Scheer Frank A. J. L. , Ronda Joseph M. , Czeisler Charles A. , Wright Kenneth P. 
Published: March 2015

SummarySleep inertia, sleep homeostatic and circadian processes modulate cognition, including reaction time, memory, mood and alertness. How these processes influence higher‐order cognitive functions is not well known. Six participants completed a 73‐day‐long study that included two 14‐day‐long 28‐h forced desynchrony protocols to examine separate and interacting influences of sleep inertia, sleep homeostasis and circadian phase on higher‐order cognitive functions of inhibitory control and selective visual attention. Cognitive performance for most measures was impaired immediately after scheduled awakening and improved during the first ~2–4 h of wakefulness (decreasing sleep inertia); worsened thereafter until scheduled bedtime (increasing sleep homeostasis); and was worst at ~60° and best at ~240° (circadian modulation, with worst and best phases corresponding to ~09:00 and ~21:00 hours, respectively, in individuals with a habitual wake time of 07:00 hours). The relative influences of sleep inertia, sleep homeostasis and circadian phase depended on the specific higher‐order cognitive function task examined. Inhibitory control appeared to be modulated most strongly by circadian phase, whereas selective visual attention for a spatial‐configuration search task was modulated most strongly by sleep inertia. These findings demonstrate that some higher‐order cognitive processes are differentially sensitive to different sleep–wake regulatory processes. Differential modulation of cognitive functions by different sleep–wake regulatory processes has important implications for understanding mechanisms contributing to performance impairments during adverse circadian phases, sleep deprivation and/or upon awakening from sleep.
Enhanced diversity and aflatoxigenicity in interspecific hybrids ofAspergillus flavusandAspergillus parasiticus
Authors: Olarte Rodrigo A. , Worthington Carolyn J. , Horn Bruce W. , Moore Geromy G. , Singh Rakhi , Monacell James T. , Dorner Joe W. , Stone Eric A. , Xie De‐Yu , Carbone Ignazio 
Published: March 2015

AbstractAspergillus flavusandA. parasiticusare the two most important aflatoxin‐producing fungi responsible for the contamination of agricultural commodities worldwide. Both species are heterothallic and undergo sexual reproduction in laboratory crosses. Here we examine the possibility of interspecific matings betweenA. flavusandA. parasiticus. These species can be distinguished morphologically and genetically, as well as by their mycotoxin profiles.Aspergillus flavusproduces both B aflatoxins and cyclopiazonic acid (CPA), B aflatoxins orCPAalone, or neither mycotoxin;Aspergillus parasiticusproduces B and G aflatoxins or the aflatoxin precursorO‐methylsterigmatocystin, but notCPA. Only four of forty‐five attempted interspecific crosses between opposite mating types ofA. flavusandA. parasiticuswere fertile and produced viable ascospores. Single ascospore strains from each cross were shown to be recombinant hybrids using multilocus genotyping and array comparative genome hybridization. Conidia of parents and their hybrid progeny were haploid and predominantly monokaryons and dikaryons based on flow cytometry. Multilocus phylogenetic inference showed that experimental hybrid progeny were grouped with naturally occurringA. flavusL strain andA. parasiticus. Higher total aflatoxin concentrations in some F1 progeny strains compared to midpoint parent aflatoxin levels indicate synergism in aflatoxin production; moreover, three progeny strains synthesized G aflatoxins that were not produced by the parents, and there was evidence of allopolyploidization in one strain. These results suggest that hybridization is an important diversifying force resulting in the genesis of novel toxin profiles in these agriculturally important fungi.
Gas Turbine Powered Blue Riband Winner
Authors: Allen Robert , Lauriat T. B. 
Published: March 2015

The high speed yacht “Gentry Eagle” has set a new record for Atlantic Ocean crossing plus two other speed records. The British built, United States owner 110 ft. craft is powered by two diesels and a centerline 4,000 hp marine gas turbine.
The paper will describe all the power plants and the propulsion system for each. Gas turbine mounting, control, inlet and exhaust treatment, and operating scenario will be covered. Craft details will be included.
History of the vessel including performance and speed run details will be noted.
An Investigation of Convective Heat Transfer in a Rotating Coolant Channel
Authors: Medwell J. O. , Morris W. D. , Xia J. Y. , Taylor C. 
Published: March 2015

A numerical method is presented for the determination of heat transfer rates in a cylindrical cooling duct within turbine blades which rotate about an axis orthogonal to its own axis of symmetry.
The equations of motion and energy are solved in conjunction with the k-ε model of turbulence using the finite element method. The predicted results are compared with experimental data and it is clearly demonstrated that conduction in the solid boundary must be taken into account if satisfactory agreement is to be achieved.
Excluding these effects can lead to an over-estimation of the maximum wall temperature by approximately 50%.
Water Treatment and Moisture Separation in Steam-Injected Gas Turbines
Authors: Kolp D. A. , Gagnon S. R. , Rosenbluth M. J. 
Published: March 2015

Steam injection has been employed in gas turbines for over twenty years. Initially the emphasis was on injection for small amounts of power augmentation and NOx reduction in the turbine exhaust gas. More recently it has been used for massive power increases (more than 50% on some gas turbines) and efficiency improvements (more than 20%). Equipment selection, operation and economics are essential ingredients in producing the high-purity steam required in a steam-injected gas turbine cycle.
The most common means of producing steam for the steam-injection cycle is by means of a waste heat boiler operating in the turbine exhaust gas stream. Steam generated in this boiler may then be injected into the compressor discharge, combustor or turbine sections of the gas turbine to improve performance.
Manufacturers require extremely high purity steam for injection into their gas turbines; less than 30 parts per billion (PPB) of some contaminants is not an unusual requirement. If this steam quality is not obtained, serious damage can occur, particularly in the turbine hot section. To meet these stringent steam quality requirements without excessive amounts of boiler blowdown, it is necessary to provide highly demineralized makeup water to the boiler, i.e. less than 1 PPM TDS (Total Dissolved Solids). Low silica concentrations are particularly important since silica can vaporize at higher boiler pressures, pass through the moisture separators and deposit on turbine components. The selection of equipment required to produce high quality makeup water from various grades of raw water is critical to the successful operation of the steam injection plant. Because the steam cannot be recovered effectively, it is necessary to install a large water treatment system to provide the quantities of makeup required for steam injection. Equally critical to the cycle is the type of drum moisture separation used in achieving manufacturers’ recommended steam quality.
Just as the steam injection cycle has a dramatic impact on the economics of a gas turbine power plant, so too do the operation and selection of steam purification equipment influence the overall economics of the steam injection cycle.
Thermo-Structural and Thermo-Fluid Dynamics Analyses Supporting the Design of the Cooling System of a Methane Liquid Rocket Engine
Authors: Ferraiuolo M. , Ricci D. , Battista F. , Roncioni P. , Salvatore V. 
Published: March 2015

The HYPROB Program, developed by the Italian Aerospace Research Centre, has the aim to increase the system design and manufacturing capabilities on liquid oxygen-methane rocket engines. It foresees the designing, manufacturing and testing of a ground engine demonstrator of three tons thrust. The demonstrator baseline concept is featured by 18 injectors and it is regeneratively cooled by using liquid methane. In particular, the cooling system is made by a constant number of axial channels and the counter-flow architecture has been chosen; methane enters the channels in the nozzle region in supercritical liquid condition, is heated by the combustion gases along the cooling jacket and then injected into the combustion chamber as a supercritical gas by means of the injection head.
The goal of this paper is to describe the thermo-structural and the thermo-fluid dynamic analyses that have been performed in order to support the design activities aiming at identifying the optimal configuration of the cooling jacket in terms of number of channels, rib height and width. In fact, a fully 3-D model, regarding a single channel, heated by the design input heat flux has been considered in order to perform CFD simulations aiming at describing the thermo-fluid dynamic behavior of methane. The results in terms of convective heat transfer coefficients have been taken into account as inputs for the thermo-structural simulations on the most critical sections of the cooling jacket. The thermo-structural activity has been conducted on the demonstrator by means of a Finite Element Method code taking into account the visco-plastic behavior of the adopted materials. In particular, transient thermal analyses and static structural analyses have been performed using ANSYS code on a 2-D model. These analyses have demonstrated that the cooling jacket can withstand the design goal of 5 thermo-mechanical cycles with a safety factor equal to 4 considering a firing time equal to 30 seconds.
Nanoscale Thermal Transport in Plasmonic Nanofocusing Structure With Strong Nonlocality
Authors: Chen Chen , Du Zhidong , Pan Liang 
Published: March 2015

Nanoscale optical energy concentration and focusing is crucial for many high-throughput nanomanufacturing applications, such as material processing, imaging and lithography. The use of surface plasmons has resulted in the rapid development of nanofocusing devices and techniques at spatial confinements as good as a few nanometers associated with strong nonlocal plasmonic response. However, operations of these plasmonic nanofocusing structures usually require extremely high optical energy density at nanoscale, which leads to intense structure heating and causes unreliable device functions and short device lifetimes. In many plasmonic applications, optical heating has become a very important issue, which has not been investigated intensively yet. In these structures, the ballistic transport and interface scattering of the energy carriers both become significant because the characteristic lengths of the devices are comparable to or smaller than the mean free paths of the carriers. A comprehensive model is desired to understand the heat generation and transport inside the plasmonic nanofocusing structures.
This work studied the electromagnetic and optothermal responses of plasmonic nanofocusing nanostructures. At the nanometer length scale, the local optical response and diffusive thermal model are no longer sufficient to describe the device optothermal response because of the strong interactions between energy carriers and the ballistic nature of carriers. Here, we used the hydrodynamic Drude model to consider the nonlocality of plasmonic response and calculate the heat generation inside the metallic nanostructures. Starting from Boltzmann transport equation, we derived the energy transport equations for both electron and phonon systems under the relaxation-time approximations. The obtained multi-carrier ballistic-diffusive model was used to study the non-equilibrium heat transports inside the structures. We assume that the ballistic electrons originate from boundaries and the electron-photon couplings inside the structure, experiencing out-scattering only in the material. The optically-generated “hot” electrons are considered as ballistic and are treated separately from the “ordinary” electrons which are in local thermal equilibrium and have significantly lower energies. Meanwhile, the electron-phonon couplings are considered under the non-equilibrium conditions between the electron and phonon systems. Using our model, we further investigated the transient optothermal responses of a one-dimensional (1D) plasmonic nanofocusing structure. In comparison to the diffusive transport description, our multi-carrier ballistic-diffusive model can more accurately describe the optothermal responses of the plasmonic nanofocusing structures which are crucial for predicting the performance and the lifetime of the plasmonic nanofocusing devices.
Probabilistic Assessment of Turbine Disk Considering Geometry Distribution Based on Surrogate Models
Authors: Fan Jiang , Wang Hao 
Published: March 2015

For rotating critical parts of aero engines, such as turbine disks, it is essential to perform reliable life predictions. Probabilistic methods are ideal to investigate these life predictions. Beside other system parameters, the distribution of geometrical parameters has a strong effect on the system behavior. However, as there are always so many geometry parameters, it always takes lots of time to complete such a probabilistic analysis considering geometry.
Within this paper, a probabilistic method based on two surrogate models is proposed and applied to an analysis of a turbine disk. In order to save the computation time as well as to get accurate results, this process is divided into two cycles. The purpose of the first cycle is to filter the parameters which have little influence on the life of the disk. In this cycle, DOE method is used and a normal response surface is created as a surrogate model to calculate the sensitivities of all the input parameters. With the sensitivities some key parameters can be selected as the inputs for the second cycle. In the second cycle DACE method is used and a more accurate Kriging model is created as the surrogate model. By conducting MCS on the calculated Kriging model, the reliability of the turbine disk can be get. In this way a huge number of computations can be avoided, thus much time can be saved and the computational efficiency can be improved.
Process Analysis of Expert and Non-Expert Engineer in Quartz Glass
Authors: Suda Masamichi , Qiu Peng , Takahashi Toru , Hattori Akio , Yang Yuqiu , Goto Akihiko , Hamada Hiroyuki 
Published: March 2015

Quartz glass is a special glass material known as “King of Glass”. The silicon purity of the quartz glass is very high, therefore it is excellent in heat resistance, chemical resistance and optical transparency as compared to other glasses, such as borosilicate glass.
At present, it is used in the production field of leading-edge. Now researches are carried out to develop it as key components of special manufacturing equipment, scientific instruments and analysis equipment that require high-precision, high purity, the high light transmittance. However, due to its high heat resistance, it is difficult to be processed into various shapes. As a result, manufactured quarts glass products, generally, might be different even in one batch. To respond to such products for precision instruments, it is preferable to select the heat molding process by flame called “fire-process” in many cases. “fire-process” is the process of forming a softening point of heated quartz glass material by a mixed combustion flame of hydrogen and oxygen. Therefore, a technique for forming a glass material softened by heating is required, and now it is done by human hand processing of engineers. While skilled human technique of long time experience is required in order to produce high precision and an efficient products. Therefore digitizing and analysis of the work of expert engineers with high level of hand skill is needed to increase the processing technology of the engineers less skilled and take advantage in the manufacture of high-precision products. In this study, the differences in the working process between engineers with different years of experience during the “fire-process” of quartz glass material were analyzed. Fire-process is of heating joint glass cylinders during rotating using a dedicated glass lathe machine. The working behaviors of three operators were recorded by videos during “fire-process”. And the thickness of jointed part of final products was measured by ultrasonic equipment to evaluate the quality of the jointed situation. It is found that these differences in the process of heating joint of glass cylinder have effects on the accuracy of finial production and the manufacturing efficiency.
Towards Automated Design of Fastening Systems for Accelerated Product Development
Authors: Friedrich C. , Hubbertz H. , Roser H. , Walker P. 
Published: March 2015

Although considered a well-established machine element, screw fastening systems are required to fulfill ever increasing demands for performance, reliability, economy, and sustainability. Yet there are limitations to the capabilities of existing design procedures which often neglect a comprehensive analysis of both soft and hard design parameters over the entire system life cycle.
This paper presents a holistic approach towards automated design of screw joints, going beyond established methods by incorporating soft (intangible) design parameters additionally. Based on the vectorial design method developed by Friedrich, a multi-objective optimization process is used to tradeoff various, often conflicting design parameters from the vectorial design approach (such as screw diameter, assembly method, preload loss, material strength, etc.) to derive an optimum solution with a high level of confidence.
For this, a complex network of strategy parameters and safety factors is used (optimization parameters). It is referred to geometry, material, contact, assembly and production for boundary conditions. A definite solution for the model of the fastening system must incorporate analytical functions, numerical relationships and correlation with technical and non-technical aspects (including cost and environmental impact).
This multi-objective approach entails inherent flexibility enabling designers to set application specific design priorities as a key part prior to defining an optimized solution. Overall, this gives the capability for an automated design process, which can be performed with computational engineering. A major benefit from this is saving product development time and therefore cost as well as evaluating influence-intensity of design parameters (rating of influencing values).
An example of a wheel bolt connection is provided to demonstrate this approach referring to a well-known application. From this it is outlined that conflicting safety factors lead to an optimum which is determined by the level of reliability or performance. The presented process offers considerable benefits in reduced development time particularly for complex, customized fastening systems, reducing unnecessary design iterations and empirical testing. The following process is intended to give a modern structure for fastener selection procedures linked with computational engineering capabilities and design experience.
Dosimetric characteristics of the novel 2D ionization chamber array OCTAVIUS Detector 1500
Authors: Stelljes T. S. , Harmeyer A. , Reuter J. , Looe H. K. , Chofor N. , Harder D. , Poppe B. 
Published: March 2015

Purpose:The dosimetric properties of the OCTAVIUS Detector 1500 (OD1500) ionization chamber array (PTW‐Freiburg, Freiburg, Germany) have been investigated. A comparative study was carried out with the OCTAVIUS Detector 729 and OCTAVIUS Detector 1000 SRS arrays.Methods:The OD1500 array is an air vented ionization chamber array with 1405 detectors in a 27 × 27 cm2 measurement area arranged in a checkerboard pattern with a chamber‐to‐chamber distance of 10 mm in each row. A sampling step width of 5 mm can be achieved by merging two measurements shifted by 5 mm, thus fulfilling the Nyquist theorem for intensity modulated dose distributions. The stability, linearity, and dose per pulse dependence were investigated using a Semiflex 31013 chamber (PTW‐Freiburg, Freiburg, Germany) as a reference detector. The effective depth of measurement was determined by measuring TPR curves with the array and a Roos chamber type 31004 (PTW‐Freiburg, Freiburg, Germany). Comparative output factor measurements were performed with the array, the Semiflex 31010 ionization chamber and the Diode 60012 (both PTW‐Freiburg, Freiburg, Germany). The energy dependence of the OD1500 was measured by comparing the array's readings to those of a Semiflex 31010 ionization chamber for varying mean photon energies at the depth of measurement, applying to the Semiflex chamber readings the correction factor kNR for nonreference conditions. The Gaussian lateral dose response function of a single array detector was determined by searching the convolution kernel suitable to convert the slit beam profiles measured with a Diode 60012 into those measured with the array's central chamber. An intensity modulated dose distribution measured with the array was verified by comparing a OD1500 measurement to TPS calculations and film measurements.Results:The stability and interchamber sensitivity variation of the OD1500 array were within ±0.2% and ±0.58%, respectively. Dose linearity was within 1% over the range from 5 to 1000 MU. The effective point of measurement of the OD1500 for dose measurements in RW3 phantoms was determined to be (8.7 ± 0.2) mm below its front surface. Output factors showed deviations below 1% for field sizes exceeding 4 × 4 cm2. The dose per pulse dependence was smaller than 0.4% for doses per pulse from 0.2 to 1 mGy. The energy dependence of the array did not exceed ±0.9%. The parameter σ of the Gaussian lateral dose response function was determined as σ6MV = (2.07 ± 0.02) mm for 6 MV and σ15MV = (2.09 ± 0.02) mm for 15 MV. An IMRT verification showed passing rates well above 90% for a local 3 mm/3% criterion.Conclusions:The OD1500 array's dosimetric properties showed the applicability of the array for clinical dosimetry with the possibility to increase the spatial sampling frequency and the coverage of a dose distribution with the sensitive areas of ionization chambers by merging two measurements.