bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transmission and Reception Properties of an Equatorial Slot Antenna on a Reentry Sphere
Authors: Harrison Charles W. , Taylor Clayborne D. 
Published: November 2015

The reentry vehicle model employed in this study consists of a plasma‐clad sphere with a narrow circumferential slot cut at the equator. The slot is excited by a biconical transmission line driven at its center by a coaxial cable. The homogeneous plasma is assumed to be in contact with the sphere.The driving‐point impedance referred to the input terminals and the radiation field in terms of the input current are determined. The efficiency of transmission is calculated by taking the ratio of the power obtained by integrating the Poynting vector over the surface of a great sphere to the power supplied the linearly tapered radial transmission line by the coaxial cable. The voltage appearing across an impedance connected to the terminals of the biconical transmission line is evaluated in terms of the amplitude of an incident plane‐wave electromagnetic field.Numerical results are presented exhibiting the transmission and reception qualities of the equatorial slot antenna on the reentry sphere for a range of frequencies and plasma properties.
Propagation of VLF Waves Below an Anisotropic Stratified Ionosphere With a Transverse Static Magnetic Field
Authors: Galejs Janis 
Published: November 2015

The surface impedance of a cylindrically stratified anisotropic ionosphere has been computed in the presence of a transverse static magnetic field without requiring explicit representations of the individual cylindrical wave functions in the lower ionospheric layers. The propagation parameters are determined from the usual transcendental modal equation which is solved starting out with an initial real solution dependent on the reactive part of the ionospheric surface impedance. The surface impedance computations are continued below the ionospheric boundary height, and the impedance reflected to the ground level by the ionosphere is compared with the ground impedance. The accuracy of the computations is shown to be comparable to a few percent uncertainty of the ground impedance for low conductivity ground.The propagation parameters of the first three waveguide modes are calculated for a number of ionosphere models which include the recent D region models of Deeks (1966). For propagation in the east‐to‐west direction, the phase velocity of the second mode is shown to be discontinuous when the real part of the ionospheric reflection coefficient undergoes a sign change. This condition is characterized by an absorption peak and for ionosphere models of lower anisotropy (lower values of ωH/v, where ωH is the gyrofrequency and v is the effective collision frequency) the interference distance D of the two lowest modes is increased for propagation in the east‐to‐west direction relative to the West‐to‐east direction. but it is decreased for larger ωH/v ratios which are representative of available models of stratified ionosphere.
Subsurface Radio Propagation Experiments
Authors: Tsao Carson K. H. , deBettencourt J. T. 
Published: November 2015

Propagation experiments were conducted on Cape Cod, the Adirondack region of New York State, and in Cheyenne Mountain in Colorado to determine the feasibility of communication between vertical linear antennas located in drill holes in the rock below overburden, and similar antennas located on the surface of the ground.The bulk conductivity of the propagation media, i.e., the average conductivity along the path between the antennas, must be determined by measurements of propagation loss and transmission delay, because of the lack of homogeneity in the rock media. High values of bulk conductivity limited experiments to the VLF relation on Cape Cod and the Adirondacks, which involved ranges of 1.6 km and 5 km. respectively. Distances up to 48 km in the LF region were achieved by up‐and‐over transmissions from inside Cheyenne Mountain.Analysis of the experimental results and theoretical considerations indicate that the usefulness of the through‐the‐rock mechanism is severely limited by the bulk conductivity. For shallow antenna depths, particularly if the overburden is thin or absent, substantial transmission ranges can be achieved by using up‐over‐down propagation.
Radiation From an Oscillating Magnetic Dipole in a Streaming Plasma
Authors: Bergeson John E. 
Published: November 2015

The electromagnetic field of an oscillating magnetic dipole is calculated, assuming that the dipole is immersed in a cold, streaming plasma. The amplitude of the magnetic dipole moment is assumed to be sufficiently weak that the linearized cold‐plasma equations may be used to describe the response of the plasma.The resulting field of the dipole is rather different from the field that would result if the plasma were not streaming. In particular, a longitudinal electrostatic field appears as a consequence of the plasma's motion. The far field of the dipole is such that the Poynting vector is not purely radial, but is tilted against the direction of the zeroth‐order plasma flow.An outward flow of mechanical energy is associated with the electrostatic field. However the mechanical energy flow is negligible for streaming velocities small compared with the velocity of light. The force necessary to hold the dipole in place is also calculated. This force vanishes when the dipole axis is parallel to the streaming direction, as does the longitudinal electric field.
Guidance in the Magnetosphere Along Field‐Alined Irregularities
Authors: Gothard Nicholas 
Published: November 2015

A study is made of guidance of waves along an inhomogeneous field‐alined plasma stratum. A time invariant model of the ionosphere imbedded in the earth's dipole field is postulated. Along the lines of flux of the earth's magnetic field bell shaped plasma strata are alined. The theory presented here is based on the mode of theory of propagation in an inhomogeneous medium and is modified to account for anisotrophy. The two‐dimensional problem is reduced to a one‐dimensional integral equation, the modal condition, by using Booker's q parameter.The numerical results are calculated for the locked modes only, although the theory is capable of handling the leaky modes as well.
The numerical results indicate the existence of total guidance between the conjugate points for some frequencies, but only partial guidance for other frequencies.
Waveguide Excitation of Dielectric and Plasma Slabs
Authors: Bates C. P. , Mittra R. 
Published: November 2015

Time‐harmonic analyses are presented for the excitation of a dielectric slab and for the excitation of an isotropic, incompressible, plasma slab by means of a parallel‐plate waveguide with one plate truncated. Both TE and TM polarizations are considered in these open‐region problems.The principal contribution of the paper is the development of a procedure for factoring the function of a complex variable which appears in the formulation of each of these Wiener‐Hopf type boundary value problems. The technique obtains the factorization for the open‐region problem by a limiting procedure on a function and its factorization associated with a related closed‐region problem. The latter factorization is usually trivial. The technique is quite general and should find application to a wide range of Wiener‐Hopf problems involving open regions.Details of the investigation including the results of numerical computations are presented for the excitation problems. These include the average power reflected in the waveguide, radiated in the space wave, and transmitted by the surface waves. The radiation pattern of the space wave is also given.
A Modified Reflection Coefficient for Layered Media
Authors: Adams Roy N. 
Published: November 2015

The energy leaving an antenna is considered as a series of rays reflected to a distant antenna. Each ray forms many reflected rays at each layer and invariant imbedding is used to study those rays of interest (i.e., rays forming a triangular zone connecting the antennas) and all others are considered lost.The modified reflection coefficient differs by several dB in some cases from the conventional plane‐wave reflection coefficient.
Surface Wave Propagation Over a Thin Plasma Layer on a Ground Plane
Authors: Lee W. C.‐Y. , Walter C. H. 
Published: November 2015

A theoretical study is made of the propagation of surface waves along an infinite, perfectly conducting plane surface that is coated with a layer of plasma and subjected to an applied d‐c magnetic field perpendicular to the layer. The electric and magnetic fields are computed for the separate media and the relations arising from boundary conditions are expressed as transcendental equations.In the limiting case of small plasma layer thickness the fields and propagation constants may be expressed in simple forms. Curves of phase velocity versus plasma thickness are illustrated with different plasma frequencies and cyclotron frequencies. It is found that a backward wave occurs for a certain range of plasma frequencies.The thin slab approximation used in this paper is checked by comparing both exact solution and approximate solution in the case of no applied d‐c magnetic field. The error is found to be very small.
Scintillation Observations at Medium Latitude Geomagnetically Conjugate Stations
Authors: Yeh K. C. , Simonich D. , Mawdsley J. , Preddey G. F. 
Published: November 2015

The present investigation is concerned with scintillation observations of radio signals at 40 MHz from satellite BE‐B recorded at Adak, Alaska, and at Wellington, New Zealand. The point conjugate to Adak is approximately 1000 km west of Wellington along a constant L shell. The nigttime irregularity patches that cause scintillation have a dimension 500 km in the north‐outh direction and much larger in the east‐west direction. Therefore, Adak and Wellington are sufficiently close to being a conjugate pair to permit a meaningful correlation of scintillation study.One year's data have been studied, extending from October 1964, through October 1965. The nighttime scintillation shows a semiannual variation especially equatorward of Adak and Wellington.Cross‐correlation studies indicate that the conjugate effect is statistically significant at night, but not in daytime. There is also an indication of slight asymmetry with respect to L shells. When the time difference of observations at the two stations is reduced from 2 ½ hr to ½ hr, the correlation coefficient is increased from 0.46 to 0.56. This suggests the time variability of the phenomenon under study.
Analysis of Spectra of Atmospheric Refractive Index Differences
Authors: Straiton A. W. , Deam A. P. , Dodd J. L. , Fannin B. M. 
Published: November 2015

When atmospheric refractive index is observed by measuring the index differences between two points, a filtering action is introduced in the fluctuation spectra. A filter function is obtained when the refractive index difference spectra frequency component is divided by the corresponding frequency component of the index spectra for a single‐point data. Test results of this filter function are compared with theoretical models.The measured filter functions for 12 data samples obtained with four refractometers on top of an 85‐m tower, are presented. These 12 cases are arranged in the order of increasing wind variability; that is, of increasing ratio of rms wind‐speed variation to the mean‐wind speed.The measured data are compared with theoretical filter functions derived assuming a “frozen‐atmosphere” model; a statistically homogeneous and isotropic invariant structure being assumed to be carried along at the mean‐wind velocity. A single mean‐wind velocity is assumed for those periods for which the measured wind data indicate a nearly constant flow. For more variable situations an integration over a range of mean‐wind speeds and wind directions is performed.Though there are numerous marked differences between the measured and calculated filter functions (as would be expected whenever a crude model is used to predict results for a truly complex situation), the model assumed does provide satisfactory explanations for many of the observed features.An unexplained anomaly, which appears in the measured filter function for many of the cases, is that at the high‐frequency end, the functions are lower than predicted.
Efficient production of gamma-aminobutyric acid using Escherichia coli by co-localization of glutamate synthase, glutamate decarboxylase, and GABA transporter
Authors: Dung Pham Van , Somasundaram Sivachandiran , Lee Seung Hwan , Park Si Jae , Hong Soon Ho 
Published: November 2015

Abstract
Gamma-aminobutyric acid (GABA) is an important bio-product, which is used in pharmaceutical formulations, nutritional supplements, and biopolymer monomer. The traditional GABA process involves the decarboxylation of glutamate. However, the direct production of GABA from glucose is a more efficient process. To construct the recombinant strains of Escherichia coli, a novel synthetic scaffold was introduced. By carrying out the co-localization of glutamate synthase, glutamate decarboxylase, and GABA transporter, we redirected the TCA cycle flux to GABA pathway. The genetically engineered E. coli strain produced 1.08 g/L of GABA from 10 g/L of initial glucose. Thus, with the introduction of a synthetic scaffold, we increased GABA production by 2.2-fold. The final GABA concentration was increased by 21.8 % by inactivating competing pathways.
Diagnosing Septic Arthritis in the Synovial White Cell Count “Gray Zone”
Authors: Ruzbarsky Joseph J. , Gladnick Brian P. , Dodwell Emily 
Published: November 2015

Differentiating septic arthritis of the pediatric hip from other causes of hip pain and effusion continues to present a diagnostic challenge for the clinician. Although septic arthritis traditionally has been reported to have a synovial white blood cell count of 75, 000 cells/mm3 or greater, lower counts can be seen in this condition. In cases where a synovial sample has been obtained and the cell count falls in the intermediate range between 25, 000 and 75, 000 cells/mm3, it is unclear what proportion of these cases may be truly septic hips. In this evidence-based review, we examine Heyworth et al's study focusing on the predictive value of this intermediate white cell count range in a Lyme-endemic region.
Hydrogen Susceptibility of Nanostructured Bainitic Steels
Authors: Peet Mathew James , Hojo Tomohiko 
Published: November 2015

Abstract
Nanostructured steels with an ultimate tensile strength of 1.6 GPa were produced with austenite content varying from 0 to 35 vol pct. The effect on the mechanical properties was assessed after saturating the steel with hydrogen. Elongation was reduced to 2 to 5 pct and UTS to 65 to 70 pct of prior value. Thermal desorption measurements confirmed the higher solubility of hydrogen in the steel with higher austenite content. The level of hydrogen saturation was found to correlate to the total area of grain boundaries rather than to the volume fraction of retained austenite.
2‐Ethylhexanol Derivatives as Nonionic Surfactants: Synthesis and Properties
Authors: Hreczuch Wiesław , Dąbrowska Karolina , Chruściel Arkadiusz , Sznajdrowska Agata , Materna Katarzyna 
Published: November 2015

AbstractThe synthesis and basic properties of 2‐ethylhexanol based innovative nonionic surfactants are described in this paper. 2‐Ethylhexanol as an available and relatively inexpensive raw material was used as the hydrophobe source modified by propoxylation and followed by polyethoxylation. As the result, six series of 2‐ethylhexyl alcohol polyalkoxylates (EHPmEn) were obtained with three steps of propoxylation, each followed by polyethoxylation and two series only with polyethoxylation (EHEn). Two different catalysts were used, a dimetalcyanide and KOH. Values of average conversion rates and chemical content of the obtained products (GC, TG and GPC techniques) were compared. The influence of the applied catalyst and polyaddition degree on the homologue distribution, reactant conversion and amount of byproducts is discussed. The basic physicochemical parameters including refractive index, solubility in polar media, foaming properties and wettability were investigated and compared. Furthermore, surface activity parameters, i.e. surface tension (γCMC) and critical micelle concentrations were determined. Results are compared to C12–14 alcohol ethoxylates (LaEn). Accordingly, it was found that the studied 2‐ethylhexyl alcohol based compounds are effective, low foaming nonionic surfactants.
Revisiting Human Cholesterol Synthesis and Absorption: The Reciprocity Paradigm and its Key Regulators
Authors: Alphonse Peter A. S. , Jones Peter J. H. 
Published: November 2015

AbstractHypercholesterolemia is a major risk factor for cardiovascular disease. Cholesterol homeostasis in the body is governed by the interplay between absorption, synthesis, and excretion or conversion of cholesterol into bile acids. A reciprocal relationship between cholesterol synthesis and absorption is known to regulate circulating cholesterol in response to dietary or therapeutic interventions. However, the degree to which these factors affect synthesis and absorption and the extent to which one vector shifts in response to the other are not thoroughly understood. Also, huge inter‐individual variability exists in the manner in which the two systems act in response to any cholesterol‐lowering treatment. Various factors are known to account for this variability and in light of recent experimental advances new players such as gene–gene interactions, gene–environmental effects, and gut microbiome hold immense potential in offering an explanation to the complex traits of inter‐individual variability in human cholesterol metabolism. In this context, the objective of the present review is to provide an overview on cholesterol metabolism and discuss the role of potential factors such as genetics, epigenetics, epistasis, and gut microbiome, as well as other regulators in modulating cholesterol metabolism, especially emphasizing the reciprocal relationship between cholesterol synthesis and absorption. Furthermore, an evaluation of the implications of this push–pull mechanism on cholesterol‐lowering strategies is presented.
Enzymatic Interesterification of High Oleic Sunflower Oil and Tripalmitin or Tristearin
Authors: Ifeduba Ebenezer A. , Martini Silvana , Akoh Casimir C. 
Published: November 2015

AbstractThe objective of this study was to produce low saturated, zero‐trans, interesterified fats with 20 or 30 % saturated fatty acids (SFA) such as C16:0 or C18:0. Tripalmitin (TP) or tristearin (TS) was blended with high oleic sunflower oil (HOSO) at different ratios (0.1:1, 0.3:1, and 0.5:1 [w/w]). Total C16:0 and C18:0 compositions of the resulting TP/HOSO and TS/HOSO blends, respectively, were plotted against blending ratios. Linear interpolation was used to estimate blending ratios that would yield physical blends (PB) with 20 or 30 % SFA. Interesterified blends (IB) were then synthesized from the customized PB using Lipozyme TL IM as the biocatalyst. Total and sn‐2 fatty acid compositions, triacylglycerol (TAG) molecular species, thermal behavior, and oxidative stability of PB and IB were compared. The total fatty acid compositions of PB and IB were similar but fatty acid positional distributions and TAG molecular species composition differed. IB contained 5–10 % more SFA at the sn‐2 position than corresponding PB. Furthermore, interesterification generated mono‐ and disaturated TAG species which resulted in broader melting profiles for IB. However, IB had lower oxidative stability than PB. The reformulation of food products with zero‐trans interesterified fats may be advantageous to the reduction of cardiovascular disease burden in the population.
Effect of Cyber-Golfing on Balance Amongst the Elderly in Hong Kong: A Pilot Randomised Trial
Authors: Chow Daniel H.K. , Mann Stephen K.F. 
Published: November 2015

Background/Objective Recent evidence showed that golf can develop balance amongst the elderly. This study aimed at evaluating if exergaming, in particular cyber-golfing, can be a feasible and inexpensive alternative to this valuable exercise. Methods Twenty healthy community-dwelling elderly were recruited, and they were randomly assigned to either the experimental group (n = 10) or the control group (n = 10). Daily cyber-golfing training for 2 weeks was assigned to the participants of the experimental group, where regular table games with equal lengths and durations were arranged for the control group. Results The results revealed that the participants in the experimental group showed significantly better post-training performances in the functional-reach test, F(2,17) = 5.16, p = .04, and single-leg-stance test, F(2,17) = 5.32, p = .03, than those in the control group. Conclusion The results of this study suggest that cyber-golfing might be an alternative to golfing, which is capable of enhancing balance ability amongst community-dwelling elderly. The potential of exergaming as a clinical tool for geriatric rehabilitation was discussed.
Estimating conductivity anisotropy of lower mantle from geomagnetic observatory data
Authors: Plotkin V.V. , Dyad’kov P.G. , Ovchinnikov S.G. 
Published: November 2015

Abstract
Anisotropy of electrical conductivity in the lower mantle, presumably caused by phase change of dielectric magnesiowüstite, can be estimated from geomagnetic records of the globally distributed geomagnetic array. The components of the conductivity tensor corresponding to the tangential components of the geomagnetic field are obtained from the magnetic mode alone recorded on the surface. Inversion by the perturbation method is applied to monthly means of geomagnetic variations along the X, Y, and Z components for the period from 1920 to 2009, borrowed from the World Monthly Means Database. The anisotropy contribution is expressed as corrections to the conductivity tensor components. The contribution of anisotropy to induction responses becomes notable for geomagnetic variations with at least decadal periods and increases with the period length.
Investigation of density contrasts and geologic structures of hot springs in the Markazi Province of Iran using the gravity method
Authors: Nouraliee J. , Porkhial S. , Mohammadzadeh-Moghaddam M. , Mirzaei S. , Ebrahimi D. , Rahmani M.R. 
Published: November 2015

Abstract
In 2012, the renewable energy organization of Iran (SUNA) performed a gravity survey around hot springs of the Mahallat geothermal field in the Markazi Province of Central Iran, as part of the explorations and developments of geothermal energy investigation program in the region. The Mahallat region has the greatest geothermal field in Iran. This work presents interpretation results of various gravity maps and a calculated 3D inversion model. The residual gravity map shows three negative gravity anomaly zones (A1, A2, and A3) associated with the geothermal reservoirs in the region. The horizontal gradient maps reveal a complex fault system. In order to attain more information about the Khorhe geothermal reservoir, a 3D density contrast model was calculated using the Li–Oldenburg method. The attained 3D model provides an in-depth image of the evolution, showing the density contrast and the A1 zone having a high potential for the geothermal reservoir in the region. The results also show that the rocks which exist between 1000 and 3000 meters under the Earth’s surface in the A1 zone are the most suitable aquifers for utilization of geothermal energy.