The effect of manganese oxide on the sinterability of hydroxyapatite

The sinterability of manganese oxide (MnO2) doped hydroxyapatite (HA) ranging from 0.05 to 1 wt% was investigated. Green samples were prepared and sintered in air at temperatures ranging from 1000 to 1400 °C. Sintered bodies were characterized to determine the phase stability, grain size, bulk density, hardness, fracture toughness and Young's modulus. XRD analysis revealed that the HA phase stability was not disrupted throughout the sintering regime employed. In general, samples containing less than 0.5 wt% MnO2 and when sintered at lower temperatures exhibited higher mechanical properties than the undoped HA. The study revealed that all the MnO2-doped HA achieved >99% relative density when sintered at 1100–1250 °C as compared to the undoped HA which could only attained highest value of 98.9% at 1150 °C. The addition of 0.05 wt% MnO2 was found to be most beneficial as the samples exhibited the highest hardness of 7.58 GPa and fracture toughness of 1.65 MPam1/2 as compared to 5.72 GPa and 1.22 MPam1/2 for the undoped HA when sintered at 1000 °C. Additionally, it was found that the MnO2-doped samples attained E values above 110 GPa when sintered at temperature as low as 1000 °C if compared to 1050 °C for the undoped HA

Potential conjunctive water resources use plan for the Grand Prairie region of Eastern Arkansas

The main objective of this study is to develop two conjunctive water use strategies that can satisfy maximum potential irrigation water demand in the Grand Prairie region of Arkansas. for climatically average growing seasons. To accomplish this. the potential irrigation demand in each 3 mile x 3 mile cell of the study area is first determined on a monthly and seasonal basis for average climatic conditions. The potential demand is also calculated for dry climatic conditions. although these latter demand figures are not used in developing the potential conjunctive water use strategies

Superfluid turbulence and pulsar glitch statistics

Experimental evidence is reviewed for the existence of superfluid turbulence in a differentially rotating, spherical shell at high Reynolds numbers (\Rey\gsim 10^3), such as the outer core of a neutron star. It is shown that torque variability increases with \Rey, suggesting that glitch activity in radio pulsars may be a function of \Rey as well. The \Rey distribution of the 67 glitching radio pulsars with characteristic ages $\tau_c \leq 10^6$ {\rm yr} is constructed from radio timing data and cooling curves and compared with the \Rey distribution of all 348 known pulsars with $\tau_c \leq 10^6$ {\rm yr}. The two distributions are different, with a Kolmogorov-Smirnov probability $\geq 1 - 3.9 \times 10^{-3}$. The conclusion holds for (modified) Urca and nonstandard cooling, and for Newtonian and superfluid viscosities

Verification of Java Bytecode using Analysis and Transformation of Logic Programs

State of the art analyzers in the Logic Programming (LP) paradigm are nowadays mature and sophisticated. They allow inferring a wide variety of global properties including termination, bounds on resource consumption, etc. The aim of this work is to automatically transfer the power of such analysis tools for LP to the analysis and verification of Java bytecode (JVML). In order to achieve our goal, we rely on well-known techniques for meta-programming and program specialization. More precisely, we propose to partially evaluate a JVML interpreter implemented in LP together with (an LP representation of) a JVML program and then analyze the residual program. Interestingly, at least for the examples we have studied, our approach produces very simple LP representations of the original JVML programs. This can be seen as a decompilation from JVML to high-level LP source. By reasoning about such residual programs, we can automatically prove in the CiaoPP system some non-trivial properties of JVML programs such as termination, run-time error freeness and infer bounds on its resource consumption. We are not aware of any other system which is able to verify such advanced properties of Java bytecode

Structural Design, Development and Testing of a Small Experimental Satellite: SATEX-1

A 50 kg. satellite is being developed at the University of Mexico as an engineering test bed. SATEX-1 is programmed to be launched to polar orbit early in 1995 by Ariane. The satellite structure comprises aluminum sandwich panels and composites in the form of a cube made with two matting U-shaped parts. This solution was selected for simplicity during assembly and testing. The s/c body is further stiffened by an internal panel which supports a pressurized gas tank and other hardware. All panels are joined by standard corner and edge close-outs and splices. At present, a finite element model for the validation of the design, regarding static and dynamic behavior is being conducted. The paper presents numerical results for quasi static and dynamic analysis, such as eigen-values, free vibration and sinusoidal vibrations. The testing program follows closely launcher agency requirements and is supported by previous similar experiences in our laboratory. Also, a general description of the project is included

Stationary waves and slowly moving features in the night upper clouds of Venus

At the cloud top level of Venus (65-70 km altitude) the atmosphere rotates 60 times faster than the underlying surface, a phenomenon known as superrotation. Whereas on Venus's dayside the cloud top motions are well determined and Venus general circulation models predict a mean zonal flow at the upper clouds similar on both day and nightside, the nightside circulation remains poorly studied except for the polar region. Here we report global measurements of the nightside circulation at the upper cloud level. We tracked individual features in thermal emission images at 3.8 and 5.0 $\mathrm{\mu m}$ obtained between 2006 and 2008 by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS-M) onboard Venus Express and in 2015 by ground-based measurements with the Medium-Resolution 0.8-5.5 Micron Spectrograph and Imager (SpeX) at the National Aeronautics and Space Administration Infrared Telescope Facility (NASA/IRTF). The zonal motions range from -110 to -60 m s$^{-1}$, consistent with those found for the dayside but with larger dispersion. Slow motions (-50 to -20 m s$^{-1}$) were also found and remain unexplained. In addition, abundant stationary wave patterns with zonal speeds from -10 to +10 m s$^{-1}$ dominate the night upper clouds and concentrate over the regions of higher surface elevation.Comment: 15 pages, 4 figures, 6 supplementary figure

Reflexiones en torno a la experiencia de coordinación de los estudios del Grado en Derecho en la Facultad de Derecho de la Universidad de Extremadura. La nueva realidad del profesor universitario ante el E.E.E.S.

El autor reflexiona desde su experiencia como Coordinador del Grado en Derecho de la Facultad de Derecho de la UEx, sobre la nueva realidad del E.E.E.S. que obliga al profesorado a tener que replantearse los tradicionales sistemas pedagógicos y metodológicos. Se resalta la necesaria formación activa y participación del alumnado. Se destaca el necesario esfuerzo del profesor destinado a preparar las vías de formación de los alumnos, tales como trabajos, seminarios, etc.; y en la propia formación al tener que estar preparados para afrontar cualquier espontanea duda que se nos platee, para conducir, tutelar y formar a los alumnos en el E.E.E.S.The author thinks from his experience as Coordinator of the Degree in Law of the Faculty of Law of the UEx, on the new reality of the E.E.E.S. that forces to the professorship to have to rethink the traditional pedagogic and methodological systems. There is highlighted the necessary active formation and participation of the student body. Is outlined the necessary effort of the teacher destined to prepare the routes of formation of the pupils, such as works, seminars, etc.; and in the own formation on having had to be prepared to confront any spontaneous doubt that silvers us, to drive, tutelary and to form the pupils in the E.E.E.S.peerReviewe

El arbitraje de consumo y los medios telemáticos

Análisis del Arbitraje de Consumo (sistema alternativo de resolución de conflictos) mediante el uso de sistemas telemáticos ante la contratación electrónica en el marco de la sociedad de la información.Analysis of Consumer Arbitration (Alternative Dispute Resolution [A.D.R.]) for use telematic system in electronic procurement in the framework of information society.peerReviewe

Two-particle irreducible effective action approach to nonlinear current conserving approximations in driven systems

Using closed-time path two-particle irreducible coarse-grained effective action (CTP 2PI CGEA) techniques, we study the response of an open interacting electronic system to time-dependent external electromagnetic fields. We show that the CTP 2PI CGEA is invariant under a simultaneous gauge transformation of the external field and the full Schwinger-Keldysh propagator, and that this property holds even when the loop expansion of the CTP 2PI CGEA is truncated at arbitrary order. The effective action approach provides a systematic way of calculating the propagator and response functions of the system, via the Schwinger-Dyson equation and the Bethe-Salpeter equations, respectively. We show that, due to the invariance of the CTP 2PI CGEA under external gauge transformations, the response functions calculated from it satisfy the Ward-Takahashi hierarchy, thus warranting the conservation of the electronic current beyond the expectation value level. We also clarify the connection between nonlinear response theory and the WT hierarchy, and discuss an example of an ad hoc approximation that violate it. These findings may be useful in the study of current fluctuations in correlated electronic pumping devices.Comment: 30 pages. Accepted for publication in JPC